xref: /freebsd/contrib/llvm-project/llvm/lib/Bitcode/Reader/BitcodeReader.cpp (revision ec0ea6efa1ad229d75c394c1a9b9cac33af2b1d3)
1 //===- BitcodeReader.cpp - Internal BitcodeReader implementation ----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Bitcode/BitcodeReader.h"
10 #include "MetadataLoader.h"
11 #include "ValueList.h"
12 #include "llvm/ADT/APFloat.h"
13 #include "llvm/ADT/APInt.h"
14 #include "llvm/ADT/ArrayRef.h"
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/Optional.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/ADT/Triple.h"
22 #include "llvm/ADT/Twine.h"
23 #include "llvm/Bitcode/BitcodeCommon.h"
24 #include "llvm/Bitcode/LLVMBitCodes.h"
25 #include "llvm/Bitstream/BitstreamReader.h"
26 #include "llvm/Config/llvm-config.h"
27 #include "llvm/IR/Argument.h"
28 #include "llvm/IR/Attributes.h"
29 #include "llvm/IR/AutoUpgrade.h"
30 #include "llvm/IR/BasicBlock.h"
31 #include "llvm/IR/CallingConv.h"
32 #include "llvm/IR/Comdat.h"
33 #include "llvm/IR/Constant.h"
34 #include "llvm/IR/Constants.h"
35 #include "llvm/IR/DataLayout.h"
36 #include "llvm/IR/DebugInfo.h"
37 #include "llvm/IR/DebugInfoMetadata.h"
38 #include "llvm/IR/DebugLoc.h"
39 #include "llvm/IR/DerivedTypes.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/GVMaterializer.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalIndirectSymbol.h"
45 #include "llvm/IR/GlobalObject.h"
46 #include "llvm/IR/GlobalValue.h"
47 #include "llvm/IR/GlobalVariable.h"
48 #include "llvm/IR/InlineAsm.h"
49 #include "llvm/IR/InstIterator.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/Intrinsics.h"
54 #include "llvm/IR/LLVMContext.h"
55 #include "llvm/IR/Metadata.h"
56 #include "llvm/IR/Module.h"
57 #include "llvm/IR/ModuleSummaryIndex.h"
58 #include "llvm/IR/Operator.h"
59 #include "llvm/IR/Type.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/Verifier.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Compiler.h"
66 #include "llvm/Support/Debug.h"
67 #include "llvm/Support/Error.h"
68 #include "llvm/Support/ErrorHandling.h"
69 #include "llvm/Support/ErrorOr.h"
70 #include "llvm/Support/ManagedStatic.h"
71 #include "llvm/Support/MathExtras.h"
72 #include "llvm/Support/MemoryBuffer.h"
73 #include "llvm/Support/raw_ostream.h"
74 #include <algorithm>
75 #include <cassert>
76 #include <cstddef>
77 #include <cstdint>
78 #include <deque>
79 #include <map>
80 #include <memory>
81 #include <set>
82 #include <string>
83 #include <system_error>
84 #include <tuple>
85 #include <utility>
86 #include <vector>
87 
88 using namespace llvm;
89 
90 static cl::opt<bool> PrintSummaryGUIDs(
91     "print-summary-global-ids", cl::init(false), cl::Hidden,
92     cl::desc(
93         "Print the global id for each value when reading the module summary"));
94 
95 namespace {
96 
97 enum {
98   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
99 };
100 
101 } // end anonymous namespace
102 
103 static Error error(const Twine &Message) {
104   return make_error<StringError>(
105       Message, make_error_code(BitcodeError::CorruptedBitcode));
106 }
107 
108 static Error hasInvalidBitcodeHeader(BitstreamCursor &Stream) {
109   if (!Stream.canSkipToPos(4))
110     return createStringError(std::errc::illegal_byte_sequence,
111                              "file too small to contain bitcode header");
112   for (unsigned C : {'B', 'C'})
113     if (Expected<SimpleBitstreamCursor::word_t> Res = Stream.Read(8)) {
114       if (Res.get() != C)
115         return createStringError(std::errc::illegal_byte_sequence,
116                                  "file doesn't start with bitcode header");
117     } else
118       return Res.takeError();
119   for (unsigned C : {0x0, 0xC, 0xE, 0xD})
120     if (Expected<SimpleBitstreamCursor::word_t> Res = Stream.Read(4)) {
121       if (Res.get() != C)
122         return createStringError(std::errc::illegal_byte_sequence,
123                                  "file doesn't start with bitcode header");
124     } else
125       return Res.takeError();
126   return Error::success();
127 }
128 
129 static Expected<BitstreamCursor> initStream(MemoryBufferRef Buffer) {
130   const unsigned char *BufPtr = (const unsigned char *)Buffer.getBufferStart();
131   const unsigned char *BufEnd = BufPtr + Buffer.getBufferSize();
132 
133   if (Buffer.getBufferSize() & 3)
134     return error("Invalid bitcode signature");
135 
136   // If we have a wrapper header, parse it and ignore the non-bc file contents.
137   // The magic number is 0x0B17C0DE stored in little endian.
138   if (isBitcodeWrapper(BufPtr, BufEnd))
139     if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
140       return error("Invalid bitcode wrapper header");
141 
142   BitstreamCursor Stream(ArrayRef<uint8_t>(BufPtr, BufEnd));
143   if (Error Err = hasInvalidBitcodeHeader(Stream))
144     return std::move(Err);
145 
146   return std::move(Stream);
147 }
148 
149 /// Convert a string from a record into an std::string, return true on failure.
150 template <typename StrTy>
151 static bool convertToString(ArrayRef<uint64_t> Record, unsigned Idx,
152                             StrTy &Result) {
153   if (Idx > Record.size())
154     return true;
155 
156   Result.append(Record.begin() + Idx, Record.end());
157   return false;
158 }
159 
160 // Strip all the TBAA attachment for the module.
161 static void stripTBAA(Module *M) {
162   for (auto &F : *M) {
163     if (F.isMaterializable())
164       continue;
165     for (auto &I : instructions(F))
166       I.setMetadata(LLVMContext::MD_tbaa, nullptr);
167   }
168 }
169 
170 /// Read the "IDENTIFICATION_BLOCK_ID" block, do some basic enforcement on the
171 /// "epoch" encoded in the bitcode, and return the producer name if any.
172 static Expected<std::string> readIdentificationBlock(BitstreamCursor &Stream) {
173   if (Error Err = Stream.EnterSubBlock(bitc::IDENTIFICATION_BLOCK_ID))
174     return std::move(Err);
175 
176   // Read all the records.
177   SmallVector<uint64_t, 64> Record;
178 
179   std::string ProducerIdentification;
180 
181   while (true) {
182     BitstreamEntry Entry;
183     if (Expected<BitstreamEntry> Res = Stream.advance())
184       Entry = Res.get();
185     else
186       return Res.takeError();
187 
188     switch (Entry.Kind) {
189     default:
190     case BitstreamEntry::Error:
191       return error("Malformed block");
192     case BitstreamEntry::EndBlock:
193       return ProducerIdentification;
194     case BitstreamEntry::Record:
195       // The interesting case.
196       break;
197     }
198 
199     // Read a record.
200     Record.clear();
201     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
202     if (!MaybeBitCode)
203       return MaybeBitCode.takeError();
204     switch (MaybeBitCode.get()) {
205     default: // Default behavior: reject
206       return error("Invalid value");
207     case bitc::IDENTIFICATION_CODE_STRING: // IDENTIFICATION: [strchr x N]
208       convertToString(Record, 0, ProducerIdentification);
209       break;
210     case bitc::IDENTIFICATION_CODE_EPOCH: { // EPOCH: [epoch#]
211       unsigned epoch = (unsigned)Record[0];
212       if (epoch != bitc::BITCODE_CURRENT_EPOCH) {
213         return error(
214           Twine("Incompatible epoch: Bitcode '") + Twine(epoch) +
215           "' vs current: '" + Twine(bitc::BITCODE_CURRENT_EPOCH) + "'");
216       }
217     }
218     }
219   }
220 }
221 
222 static Expected<std::string> readIdentificationCode(BitstreamCursor &Stream) {
223   // We expect a number of well-defined blocks, though we don't necessarily
224   // need to understand them all.
225   while (true) {
226     if (Stream.AtEndOfStream())
227       return "";
228 
229     BitstreamEntry Entry;
230     if (Expected<BitstreamEntry> Res = Stream.advance())
231       Entry = std::move(Res.get());
232     else
233       return Res.takeError();
234 
235     switch (Entry.Kind) {
236     case BitstreamEntry::EndBlock:
237     case BitstreamEntry::Error:
238       return error("Malformed block");
239 
240     case BitstreamEntry::SubBlock:
241       if (Entry.ID == bitc::IDENTIFICATION_BLOCK_ID)
242         return readIdentificationBlock(Stream);
243 
244       // Ignore other sub-blocks.
245       if (Error Err = Stream.SkipBlock())
246         return std::move(Err);
247       continue;
248     case BitstreamEntry::Record:
249       if (Expected<unsigned> Skipped = Stream.skipRecord(Entry.ID))
250         continue;
251       else
252         return Skipped.takeError();
253     }
254   }
255 }
256 
257 static Expected<bool> hasObjCCategoryInModule(BitstreamCursor &Stream) {
258   if (Error Err = Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
259     return std::move(Err);
260 
261   SmallVector<uint64_t, 64> Record;
262   // Read all the records for this module.
263 
264   while (true) {
265     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
266     if (!MaybeEntry)
267       return MaybeEntry.takeError();
268     BitstreamEntry Entry = MaybeEntry.get();
269 
270     switch (Entry.Kind) {
271     case BitstreamEntry::SubBlock: // Handled for us already.
272     case BitstreamEntry::Error:
273       return error("Malformed block");
274     case BitstreamEntry::EndBlock:
275       return false;
276     case BitstreamEntry::Record:
277       // The interesting case.
278       break;
279     }
280 
281     // Read a record.
282     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
283     if (!MaybeRecord)
284       return MaybeRecord.takeError();
285     switch (MaybeRecord.get()) {
286     default:
287       break; // Default behavior, ignore unknown content.
288     case bitc::MODULE_CODE_SECTIONNAME: { // SECTIONNAME: [strchr x N]
289       std::string S;
290       if (convertToString(Record, 0, S))
291         return error("Invalid record");
292       // Check for the i386 and other (x86_64, ARM) conventions
293       if (S.find("__DATA,__objc_catlist") != std::string::npos ||
294           S.find("__OBJC,__category") != std::string::npos)
295         return true;
296       break;
297     }
298     }
299     Record.clear();
300   }
301   llvm_unreachable("Exit infinite loop");
302 }
303 
304 static Expected<bool> hasObjCCategory(BitstreamCursor &Stream) {
305   // We expect a number of well-defined blocks, though we don't necessarily
306   // need to understand them all.
307   while (true) {
308     BitstreamEntry Entry;
309     if (Expected<BitstreamEntry> Res = Stream.advance())
310       Entry = std::move(Res.get());
311     else
312       return Res.takeError();
313 
314     switch (Entry.Kind) {
315     case BitstreamEntry::Error:
316       return error("Malformed block");
317     case BitstreamEntry::EndBlock:
318       return false;
319 
320     case BitstreamEntry::SubBlock:
321       if (Entry.ID == bitc::MODULE_BLOCK_ID)
322         return hasObjCCategoryInModule(Stream);
323 
324       // Ignore other sub-blocks.
325       if (Error Err = Stream.SkipBlock())
326         return std::move(Err);
327       continue;
328 
329     case BitstreamEntry::Record:
330       if (Expected<unsigned> Skipped = Stream.skipRecord(Entry.ID))
331         continue;
332       else
333         return Skipped.takeError();
334     }
335   }
336 }
337 
338 static Expected<std::string> readModuleTriple(BitstreamCursor &Stream) {
339   if (Error Err = Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
340     return std::move(Err);
341 
342   SmallVector<uint64_t, 64> Record;
343 
344   std::string Triple;
345 
346   // Read all the records for this module.
347   while (true) {
348     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
349     if (!MaybeEntry)
350       return MaybeEntry.takeError();
351     BitstreamEntry Entry = MaybeEntry.get();
352 
353     switch (Entry.Kind) {
354     case BitstreamEntry::SubBlock: // Handled for us already.
355     case BitstreamEntry::Error:
356       return error("Malformed block");
357     case BitstreamEntry::EndBlock:
358       return Triple;
359     case BitstreamEntry::Record:
360       // The interesting case.
361       break;
362     }
363 
364     // Read a record.
365     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
366     if (!MaybeRecord)
367       return MaybeRecord.takeError();
368     switch (MaybeRecord.get()) {
369     default: break;  // Default behavior, ignore unknown content.
370     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
371       std::string S;
372       if (convertToString(Record, 0, S))
373         return error("Invalid record");
374       Triple = S;
375       break;
376     }
377     }
378     Record.clear();
379   }
380   llvm_unreachable("Exit infinite loop");
381 }
382 
383 static Expected<std::string> readTriple(BitstreamCursor &Stream) {
384   // We expect a number of well-defined blocks, though we don't necessarily
385   // need to understand them all.
386   while (true) {
387     Expected<BitstreamEntry> MaybeEntry = Stream.advance();
388     if (!MaybeEntry)
389       return MaybeEntry.takeError();
390     BitstreamEntry Entry = MaybeEntry.get();
391 
392     switch (Entry.Kind) {
393     case BitstreamEntry::Error:
394       return error("Malformed block");
395     case BitstreamEntry::EndBlock:
396       return "";
397 
398     case BitstreamEntry::SubBlock:
399       if (Entry.ID == bitc::MODULE_BLOCK_ID)
400         return readModuleTriple(Stream);
401 
402       // Ignore other sub-blocks.
403       if (Error Err = Stream.SkipBlock())
404         return std::move(Err);
405       continue;
406 
407     case BitstreamEntry::Record:
408       if (llvm::Expected<unsigned> Skipped = Stream.skipRecord(Entry.ID))
409         continue;
410       else
411         return Skipped.takeError();
412     }
413   }
414 }
415 
416 namespace {
417 
418 class BitcodeReaderBase {
419 protected:
420   BitcodeReaderBase(BitstreamCursor Stream, StringRef Strtab)
421       : Stream(std::move(Stream)), Strtab(Strtab) {
422     this->Stream.setBlockInfo(&BlockInfo);
423   }
424 
425   BitstreamBlockInfo BlockInfo;
426   BitstreamCursor Stream;
427   StringRef Strtab;
428 
429   /// In version 2 of the bitcode we store names of global values and comdats in
430   /// a string table rather than in the VST.
431   bool UseStrtab = false;
432 
433   Expected<unsigned> parseVersionRecord(ArrayRef<uint64_t> Record);
434 
435   /// If this module uses a string table, pop the reference to the string table
436   /// and return the referenced string and the rest of the record. Otherwise
437   /// just return the record itself.
438   std::pair<StringRef, ArrayRef<uint64_t>>
439   readNameFromStrtab(ArrayRef<uint64_t> Record);
440 
441   bool readBlockInfo();
442 
443   // Contains an arbitrary and optional string identifying the bitcode producer
444   std::string ProducerIdentification;
445 
446   Error error(const Twine &Message);
447 };
448 
449 } // end anonymous namespace
450 
451 Error BitcodeReaderBase::error(const Twine &Message) {
452   std::string FullMsg = Message.str();
453   if (!ProducerIdentification.empty())
454     FullMsg += " (Producer: '" + ProducerIdentification + "' Reader: 'LLVM " +
455                LLVM_VERSION_STRING "')";
456   return ::error(FullMsg);
457 }
458 
459 Expected<unsigned>
460 BitcodeReaderBase::parseVersionRecord(ArrayRef<uint64_t> Record) {
461   if (Record.empty())
462     return error("Invalid record");
463   unsigned ModuleVersion = Record[0];
464   if (ModuleVersion > 2)
465     return error("Invalid value");
466   UseStrtab = ModuleVersion >= 2;
467   return ModuleVersion;
468 }
469 
470 std::pair<StringRef, ArrayRef<uint64_t>>
471 BitcodeReaderBase::readNameFromStrtab(ArrayRef<uint64_t> Record) {
472   if (!UseStrtab)
473     return {"", Record};
474   // Invalid reference. Let the caller complain about the record being empty.
475   if (Record[0] + Record[1] > Strtab.size())
476     return {"", {}};
477   return {StringRef(Strtab.data() + Record[0], Record[1]), Record.slice(2)};
478 }
479 
480 namespace {
481 
482 class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
483   LLVMContext &Context;
484   Module *TheModule = nullptr;
485   // Next offset to start scanning for lazy parsing of function bodies.
486   uint64_t NextUnreadBit = 0;
487   // Last function offset found in the VST.
488   uint64_t LastFunctionBlockBit = 0;
489   bool SeenValueSymbolTable = false;
490   uint64_t VSTOffset = 0;
491 
492   std::vector<std::string> SectionTable;
493   std::vector<std::string> GCTable;
494 
495   std::vector<Type*> TypeList;
496   DenseMap<Function *, FunctionType *> FunctionTypes;
497   BitcodeReaderValueList ValueList;
498   Optional<MetadataLoader> MDLoader;
499   std::vector<Comdat *> ComdatList;
500   SmallVector<Instruction *, 64> InstructionList;
501 
502   std::vector<std::pair<GlobalVariable *, unsigned>> GlobalInits;
503   std::vector<std::pair<GlobalIndirectSymbol *, unsigned>> IndirectSymbolInits;
504   std::vector<std::pair<Function *, unsigned>> FunctionPrefixes;
505   std::vector<std::pair<Function *, unsigned>> FunctionPrologues;
506   std::vector<std::pair<Function *, unsigned>> FunctionPersonalityFns;
507 
508   /// The set of attributes by index.  Index zero in the file is for null, and
509   /// is thus not represented here.  As such all indices are off by one.
510   std::vector<AttributeList> MAttributes;
511 
512   /// The set of attribute groups.
513   std::map<unsigned, AttributeList> MAttributeGroups;
514 
515   /// While parsing a function body, this is a list of the basic blocks for the
516   /// function.
517   std::vector<BasicBlock*> FunctionBBs;
518 
519   // When reading the module header, this list is populated with functions that
520   // have bodies later in the file.
521   std::vector<Function*> FunctionsWithBodies;
522 
523   // When intrinsic functions are encountered which require upgrading they are
524   // stored here with their replacement function.
525   using UpdatedIntrinsicMap = DenseMap<Function *, Function *>;
526   UpdatedIntrinsicMap UpgradedIntrinsics;
527   // Intrinsics which were remangled because of types rename
528   UpdatedIntrinsicMap RemangledIntrinsics;
529 
530   // Several operations happen after the module header has been read, but
531   // before function bodies are processed. This keeps track of whether
532   // we've done this yet.
533   bool SeenFirstFunctionBody = false;
534 
535   /// When function bodies are initially scanned, this map contains info about
536   /// where to find deferred function body in the stream.
537   DenseMap<Function*, uint64_t> DeferredFunctionInfo;
538 
539   /// When Metadata block is initially scanned when parsing the module, we may
540   /// choose to defer parsing of the metadata. This vector contains info about
541   /// which Metadata blocks are deferred.
542   std::vector<uint64_t> DeferredMetadataInfo;
543 
544   /// These are basic blocks forward-referenced by block addresses.  They are
545   /// inserted lazily into functions when they're loaded.  The basic block ID is
546   /// its index into the vector.
547   DenseMap<Function *, std::vector<BasicBlock *>> BasicBlockFwdRefs;
548   std::deque<Function *> BasicBlockFwdRefQueue;
549 
550   /// Indicates that we are using a new encoding for instruction operands where
551   /// most operands in the current FUNCTION_BLOCK are encoded relative to the
552   /// instruction number, for a more compact encoding.  Some instruction
553   /// operands are not relative to the instruction ID: basic block numbers, and
554   /// types. Once the old style function blocks have been phased out, we would
555   /// not need this flag.
556   bool UseRelativeIDs = false;
557 
558   /// True if all functions will be materialized, negating the need to process
559   /// (e.g.) blockaddress forward references.
560   bool WillMaterializeAllForwardRefs = false;
561 
562   bool StripDebugInfo = false;
563   TBAAVerifier TBAAVerifyHelper;
564 
565   std::vector<std::string> BundleTags;
566   SmallVector<SyncScope::ID, 8> SSIDs;
567 
568 public:
569   BitcodeReader(BitstreamCursor Stream, StringRef Strtab,
570                 StringRef ProducerIdentification, LLVMContext &Context);
571 
572   Error materializeForwardReferencedFunctions();
573 
574   Error materialize(GlobalValue *GV) override;
575   Error materializeModule() override;
576   std::vector<StructType *> getIdentifiedStructTypes() const override;
577 
578   /// Main interface to parsing a bitcode buffer.
579   /// \returns true if an error occurred.
580   Error parseBitcodeInto(
581       Module *M, bool ShouldLazyLoadMetadata = false, bool IsImporting = false,
582       DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
583 
584   static uint64_t decodeSignRotatedValue(uint64_t V);
585 
586   /// Materialize any deferred Metadata block.
587   Error materializeMetadata() override;
588 
589   void setStripDebugInfo() override;
590 
591 private:
592   std::vector<StructType *> IdentifiedStructTypes;
593   StructType *createIdentifiedStructType(LLVMContext &Context, StringRef Name);
594   StructType *createIdentifiedStructType(LLVMContext &Context);
595 
596   Type *getTypeByID(unsigned ID);
597 
598   Value *getFnValueByID(unsigned ID, Type *Ty) {
599     if (Ty && Ty->isMetadataTy())
600       return MetadataAsValue::get(Ty->getContext(), getFnMetadataByID(ID));
601     return ValueList.getValueFwdRef(ID, Ty);
602   }
603 
604   Metadata *getFnMetadataByID(unsigned ID) {
605     return MDLoader->getMetadataFwdRefOrLoad(ID);
606   }
607 
608   BasicBlock *getBasicBlock(unsigned ID) const {
609     if (ID >= FunctionBBs.size()) return nullptr; // Invalid ID
610     return FunctionBBs[ID];
611   }
612 
613   AttributeList getAttributes(unsigned i) const {
614     if (i-1 < MAttributes.size())
615       return MAttributes[i-1];
616     return AttributeList();
617   }
618 
619   /// Read a value/type pair out of the specified record from slot 'Slot'.
620   /// Increment Slot past the number of slots used in the record. Return true on
621   /// failure.
622   bool getValueTypePair(const SmallVectorImpl<uint64_t> &Record, unsigned &Slot,
623                         unsigned InstNum, Value *&ResVal) {
624     if (Slot == Record.size()) return true;
625     unsigned ValNo = (unsigned)Record[Slot++];
626     // Adjust the ValNo, if it was encoded relative to the InstNum.
627     if (UseRelativeIDs)
628       ValNo = InstNum - ValNo;
629     if (ValNo < InstNum) {
630       // If this is not a forward reference, just return the value we already
631       // have.
632       ResVal = getFnValueByID(ValNo, nullptr);
633       return ResVal == nullptr;
634     }
635     if (Slot == Record.size())
636       return true;
637 
638     unsigned TypeNo = (unsigned)Record[Slot++];
639     ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
640     return ResVal == nullptr;
641   }
642 
643   /// Read a value out of the specified record from slot 'Slot'. Increment Slot
644   /// past the number of slots used by the value in the record. Return true if
645   /// there is an error.
646   bool popValue(const SmallVectorImpl<uint64_t> &Record, unsigned &Slot,
647                 unsigned InstNum, Type *Ty, Value *&ResVal) {
648     if (getValue(Record, Slot, InstNum, Ty, ResVal))
649       return true;
650     // All values currently take a single record slot.
651     ++Slot;
652     return false;
653   }
654 
655   /// Like popValue, but does not increment the Slot number.
656   bool getValue(const SmallVectorImpl<uint64_t> &Record, unsigned Slot,
657                 unsigned InstNum, Type *Ty, Value *&ResVal) {
658     ResVal = getValue(Record, Slot, InstNum, Ty);
659     return ResVal == nullptr;
660   }
661 
662   /// Version of getValue that returns ResVal directly, or 0 if there is an
663   /// error.
664   Value *getValue(const SmallVectorImpl<uint64_t> &Record, unsigned Slot,
665                   unsigned InstNum, Type *Ty) {
666     if (Slot == Record.size()) return nullptr;
667     unsigned ValNo = (unsigned)Record[Slot];
668     // Adjust the ValNo, if it was encoded relative to the InstNum.
669     if (UseRelativeIDs)
670       ValNo = InstNum - ValNo;
671     return getFnValueByID(ValNo, Ty);
672   }
673 
674   /// Like getValue, but decodes signed VBRs.
675   Value *getValueSigned(const SmallVectorImpl<uint64_t> &Record, unsigned Slot,
676                         unsigned InstNum, Type *Ty) {
677     if (Slot == Record.size()) return nullptr;
678     unsigned ValNo = (unsigned)decodeSignRotatedValue(Record[Slot]);
679     // Adjust the ValNo, if it was encoded relative to the InstNum.
680     if (UseRelativeIDs)
681       ValNo = InstNum - ValNo;
682     return getFnValueByID(ValNo, Ty);
683   }
684 
685   /// Upgrades old-style typeless byval/sret/inalloca attributes by adding the
686   /// corresponding argument's pointee type. Also upgrades intrinsics that now
687   /// require an elementtype attribute.
688   void propagateAttributeTypes(CallBase *CB, ArrayRef<Type *> ArgsTys);
689 
690   /// Converts alignment exponent (i.e. power of two (or zero)) to the
691   /// corresponding alignment to use. If alignment is too large, returns
692   /// a corresponding error code.
693   Error parseAlignmentValue(uint64_t Exponent, MaybeAlign &Alignment);
694   Error parseAttrKind(uint64_t Code, Attribute::AttrKind *Kind);
695   Error parseModule(
696       uint64_t ResumeBit, bool ShouldLazyLoadMetadata = false,
697       DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
698 
699   Error parseComdatRecord(ArrayRef<uint64_t> Record);
700   Error parseGlobalVarRecord(ArrayRef<uint64_t> Record);
701   Error parseFunctionRecord(ArrayRef<uint64_t> Record);
702   Error parseGlobalIndirectSymbolRecord(unsigned BitCode,
703                                         ArrayRef<uint64_t> Record);
704 
705   Error parseAttributeBlock();
706   Error parseAttributeGroupBlock();
707   Error parseTypeTable();
708   Error parseTypeTableBody();
709   Error parseOperandBundleTags();
710   Error parseSyncScopeNames();
711 
712   Expected<Value *> recordValue(SmallVectorImpl<uint64_t> &Record,
713                                 unsigned NameIndex, Triple &TT);
714   void setDeferredFunctionInfo(unsigned FuncBitcodeOffsetDelta, Function *F,
715                                ArrayRef<uint64_t> Record);
716   Error parseValueSymbolTable(uint64_t Offset = 0);
717   Error parseGlobalValueSymbolTable();
718   Error parseConstants();
719   Error rememberAndSkipFunctionBodies();
720   Error rememberAndSkipFunctionBody();
721   /// Save the positions of the Metadata blocks and skip parsing the blocks.
722   Error rememberAndSkipMetadata();
723   Error typeCheckLoadStoreInst(Type *ValType, Type *PtrType);
724   Error parseFunctionBody(Function *F);
725   Error globalCleanup();
726   Error resolveGlobalAndIndirectSymbolInits();
727   Error parseUseLists();
728   Error findFunctionInStream(
729       Function *F,
730       DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator);
731 
732   SyncScope::ID getDecodedSyncScopeID(unsigned Val);
733 };
734 
735 /// Class to manage reading and parsing function summary index bitcode
736 /// files/sections.
737 class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
738   /// The module index built during parsing.
739   ModuleSummaryIndex &TheIndex;
740 
741   /// Indicates whether we have encountered a global value summary section
742   /// yet during parsing.
743   bool SeenGlobalValSummary = false;
744 
745   /// Indicates whether we have already parsed the VST, used for error checking.
746   bool SeenValueSymbolTable = false;
747 
748   /// Set to the offset of the VST recorded in the MODULE_CODE_VSTOFFSET record.
749   /// Used to enable on-demand parsing of the VST.
750   uint64_t VSTOffset = 0;
751 
752   // Map to save ValueId to ValueInfo association that was recorded in the
753   // ValueSymbolTable. It is used after the VST is parsed to convert
754   // call graph edges read from the function summary from referencing
755   // callees by their ValueId to using the ValueInfo instead, which is how
756   // they are recorded in the summary index being built.
757   // We save a GUID which refers to the same global as the ValueInfo, but
758   // ignoring the linkage, i.e. for values other than local linkage they are
759   // identical.
760   DenseMap<unsigned, std::pair<ValueInfo, GlobalValue::GUID>>
761       ValueIdToValueInfoMap;
762 
763   /// Map populated during module path string table parsing, from the
764   /// module ID to a string reference owned by the index's module
765   /// path string table, used to correlate with combined index
766   /// summary records.
767   DenseMap<uint64_t, StringRef> ModuleIdMap;
768 
769   /// Original source file name recorded in a bitcode record.
770   std::string SourceFileName;
771 
772   /// The string identifier given to this module by the client, normally the
773   /// path to the bitcode file.
774   StringRef ModulePath;
775 
776   /// For per-module summary indexes, the unique numerical identifier given to
777   /// this module by the client.
778   unsigned ModuleId;
779 
780 public:
781   ModuleSummaryIndexBitcodeReader(BitstreamCursor Stream, StringRef Strtab,
782                                   ModuleSummaryIndex &TheIndex,
783                                   StringRef ModulePath, unsigned ModuleId);
784 
785   Error parseModule();
786 
787 private:
788   void setValueGUID(uint64_t ValueID, StringRef ValueName,
789                     GlobalValue::LinkageTypes Linkage,
790                     StringRef SourceFileName);
791   Error parseValueSymbolTable(
792       uint64_t Offset,
793       DenseMap<unsigned, GlobalValue::LinkageTypes> &ValueIdToLinkageMap);
794   std::vector<ValueInfo> makeRefList(ArrayRef<uint64_t> Record);
795   std::vector<FunctionSummary::EdgeTy> makeCallList(ArrayRef<uint64_t> Record,
796                                                     bool IsOldProfileFormat,
797                                                     bool HasProfile,
798                                                     bool HasRelBF);
799   Error parseEntireSummary(unsigned ID);
800   Error parseModuleStringTable();
801   void parseTypeIdCompatibleVtableSummaryRecord(ArrayRef<uint64_t> Record);
802   void parseTypeIdCompatibleVtableInfo(ArrayRef<uint64_t> Record, size_t &Slot,
803                                        TypeIdCompatibleVtableInfo &TypeId);
804   std::vector<FunctionSummary::ParamAccess>
805   parseParamAccesses(ArrayRef<uint64_t> Record);
806 
807   std::pair<ValueInfo, GlobalValue::GUID>
808   getValueInfoFromValueId(unsigned ValueId);
809 
810   void addThisModule();
811   ModuleSummaryIndex::ModuleInfo *getThisModule();
812 };
813 
814 } // end anonymous namespace
815 
816 std::error_code llvm::errorToErrorCodeAndEmitErrors(LLVMContext &Ctx,
817                                                     Error Err) {
818   if (Err) {
819     std::error_code EC;
820     handleAllErrors(std::move(Err), [&](ErrorInfoBase &EIB) {
821       EC = EIB.convertToErrorCode();
822       Ctx.emitError(EIB.message());
823     });
824     return EC;
825   }
826   return std::error_code();
827 }
828 
829 BitcodeReader::BitcodeReader(BitstreamCursor Stream, StringRef Strtab,
830                              StringRef ProducerIdentification,
831                              LLVMContext &Context)
832     : BitcodeReaderBase(std::move(Stream), Strtab), Context(Context),
833       ValueList(Context, Stream.SizeInBytes()) {
834   this->ProducerIdentification = std::string(ProducerIdentification);
835 }
836 
837 Error BitcodeReader::materializeForwardReferencedFunctions() {
838   if (WillMaterializeAllForwardRefs)
839     return Error::success();
840 
841   // Prevent recursion.
842   WillMaterializeAllForwardRefs = true;
843 
844   while (!BasicBlockFwdRefQueue.empty()) {
845     Function *F = BasicBlockFwdRefQueue.front();
846     BasicBlockFwdRefQueue.pop_front();
847     assert(F && "Expected valid function");
848     if (!BasicBlockFwdRefs.count(F))
849       // Already materialized.
850       continue;
851 
852     // Check for a function that isn't materializable to prevent an infinite
853     // loop.  When parsing a blockaddress stored in a global variable, there
854     // isn't a trivial way to check if a function will have a body without a
855     // linear search through FunctionsWithBodies, so just check it here.
856     if (!F->isMaterializable())
857       return error("Never resolved function from blockaddress");
858 
859     // Try to materialize F.
860     if (Error Err = materialize(F))
861       return Err;
862   }
863   assert(BasicBlockFwdRefs.empty() && "Function missing from queue");
864 
865   // Reset state.
866   WillMaterializeAllForwardRefs = false;
867   return Error::success();
868 }
869 
870 //===----------------------------------------------------------------------===//
871 //  Helper functions to implement forward reference resolution, etc.
872 //===----------------------------------------------------------------------===//
873 
874 static bool hasImplicitComdat(size_t Val) {
875   switch (Val) {
876   default:
877     return false;
878   case 1:  // Old WeakAnyLinkage
879   case 4:  // Old LinkOnceAnyLinkage
880   case 10: // Old WeakODRLinkage
881   case 11: // Old LinkOnceODRLinkage
882     return true;
883   }
884 }
885 
886 static GlobalValue::LinkageTypes getDecodedLinkage(unsigned Val) {
887   switch (Val) {
888   default: // Map unknown/new linkages to external
889   case 0:
890     return GlobalValue::ExternalLinkage;
891   case 2:
892     return GlobalValue::AppendingLinkage;
893   case 3:
894     return GlobalValue::InternalLinkage;
895   case 5:
896     return GlobalValue::ExternalLinkage; // Obsolete DLLImportLinkage
897   case 6:
898     return GlobalValue::ExternalLinkage; // Obsolete DLLExportLinkage
899   case 7:
900     return GlobalValue::ExternalWeakLinkage;
901   case 8:
902     return GlobalValue::CommonLinkage;
903   case 9:
904     return GlobalValue::PrivateLinkage;
905   case 12:
906     return GlobalValue::AvailableExternallyLinkage;
907   case 13:
908     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateLinkage
909   case 14:
910     return GlobalValue::PrivateLinkage; // Obsolete LinkerPrivateWeakLinkage
911   case 15:
912     return GlobalValue::ExternalLinkage; // Obsolete LinkOnceODRAutoHideLinkage
913   case 1: // Old value with implicit comdat.
914   case 16:
915     return GlobalValue::WeakAnyLinkage;
916   case 10: // Old value with implicit comdat.
917   case 17:
918     return GlobalValue::WeakODRLinkage;
919   case 4: // Old value with implicit comdat.
920   case 18:
921     return GlobalValue::LinkOnceAnyLinkage;
922   case 11: // Old value with implicit comdat.
923   case 19:
924     return GlobalValue::LinkOnceODRLinkage;
925   }
926 }
927 
928 static FunctionSummary::FFlags getDecodedFFlags(uint64_t RawFlags) {
929   FunctionSummary::FFlags Flags;
930   Flags.ReadNone = RawFlags & 0x1;
931   Flags.ReadOnly = (RawFlags >> 1) & 0x1;
932   Flags.NoRecurse = (RawFlags >> 2) & 0x1;
933   Flags.ReturnDoesNotAlias = (RawFlags >> 3) & 0x1;
934   Flags.NoInline = (RawFlags >> 4) & 0x1;
935   Flags.AlwaysInline = (RawFlags >> 5) & 0x1;
936   return Flags;
937 }
938 
939 // Decode the flags for GlobalValue in the summary. The bits for each attribute:
940 //
941 // linkage: [0,4), notEligibleToImport: 4, live: 5, local: 6, canAutoHide: 7,
942 // visibility: [8, 10).
943 static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
944                                                             uint64_t Version) {
945   // Summary were not emitted before LLVM 3.9, we don't need to upgrade Linkage
946   // like getDecodedLinkage() above. Any future change to the linkage enum and
947   // to getDecodedLinkage() will need to be taken into account here as above.
948   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
949   auto Visibility = GlobalValue::VisibilityTypes((RawFlags >> 8) & 3); // 2 bits
950   RawFlags = RawFlags >> 4;
951   bool NotEligibleToImport = (RawFlags & 0x1) || Version < 3;
952   // The Live flag wasn't introduced until version 3. For dead stripping
953   // to work correctly on earlier versions, we must conservatively treat all
954   // values as live.
955   bool Live = (RawFlags & 0x2) || Version < 3;
956   bool Local = (RawFlags & 0x4);
957   bool AutoHide = (RawFlags & 0x8);
958 
959   return GlobalValueSummary::GVFlags(Linkage, Visibility, NotEligibleToImport,
960                                      Live, Local, AutoHide);
961 }
962 
963 // Decode the flags for GlobalVariable in the summary
964 static GlobalVarSummary::GVarFlags getDecodedGVarFlags(uint64_t RawFlags) {
965   return GlobalVarSummary::GVarFlags(
966       (RawFlags & 0x1) ? true : false, (RawFlags & 0x2) ? true : false,
967       (RawFlags & 0x4) ? true : false,
968       (GlobalObject::VCallVisibility)(RawFlags >> 3));
969 }
970 
971 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
972   switch (Val) {
973   default: // Map unknown visibilities to default.
974   case 0: return GlobalValue::DefaultVisibility;
975   case 1: return GlobalValue::HiddenVisibility;
976   case 2: return GlobalValue::ProtectedVisibility;
977   }
978 }
979 
980 static GlobalValue::DLLStorageClassTypes
981 getDecodedDLLStorageClass(unsigned Val) {
982   switch (Val) {
983   default: // Map unknown values to default.
984   case 0: return GlobalValue::DefaultStorageClass;
985   case 1: return GlobalValue::DLLImportStorageClass;
986   case 2: return GlobalValue::DLLExportStorageClass;
987   }
988 }
989 
990 static bool getDecodedDSOLocal(unsigned Val) {
991   switch(Val) {
992   default: // Map unknown values to preemptable.
993   case 0:  return false;
994   case 1:  return true;
995   }
996 }
997 
998 static GlobalVariable::ThreadLocalMode getDecodedThreadLocalMode(unsigned Val) {
999   switch (Val) {
1000     case 0: return GlobalVariable::NotThreadLocal;
1001     default: // Map unknown non-zero value to general dynamic.
1002     case 1: return GlobalVariable::GeneralDynamicTLSModel;
1003     case 2: return GlobalVariable::LocalDynamicTLSModel;
1004     case 3: return GlobalVariable::InitialExecTLSModel;
1005     case 4: return GlobalVariable::LocalExecTLSModel;
1006   }
1007 }
1008 
1009 static GlobalVariable::UnnamedAddr getDecodedUnnamedAddrType(unsigned Val) {
1010   switch (Val) {
1011     default: // Map unknown to UnnamedAddr::None.
1012     case 0: return GlobalVariable::UnnamedAddr::None;
1013     case 1: return GlobalVariable::UnnamedAddr::Global;
1014     case 2: return GlobalVariable::UnnamedAddr::Local;
1015   }
1016 }
1017 
1018 static int getDecodedCastOpcode(unsigned Val) {
1019   switch (Val) {
1020   default: return -1;
1021   case bitc::CAST_TRUNC   : return Instruction::Trunc;
1022   case bitc::CAST_ZEXT    : return Instruction::ZExt;
1023   case bitc::CAST_SEXT    : return Instruction::SExt;
1024   case bitc::CAST_FPTOUI  : return Instruction::FPToUI;
1025   case bitc::CAST_FPTOSI  : return Instruction::FPToSI;
1026   case bitc::CAST_UITOFP  : return Instruction::UIToFP;
1027   case bitc::CAST_SITOFP  : return Instruction::SIToFP;
1028   case bitc::CAST_FPTRUNC : return Instruction::FPTrunc;
1029   case bitc::CAST_FPEXT   : return Instruction::FPExt;
1030   case bitc::CAST_PTRTOINT: return Instruction::PtrToInt;
1031   case bitc::CAST_INTTOPTR: return Instruction::IntToPtr;
1032   case bitc::CAST_BITCAST : return Instruction::BitCast;
1033   case bitc::CAST_ADDRSPACECAST: return Instruction::AddrSpaceCast;
1034   }
1035 }
1036 
1037 static int getDecodedUnaryOpcode(unsigned Val, Type *Ty) {
1038   bool IsFP = Ty->isFPOrFPVectorTy();
1039   // UnOps are only valid for int/fp or vector of int/fp types
1040   if (!IsFP && !Ty->isIntOrIntVectorTy())
1041     return -1;
1042 
1043   switch (Val) {
1044   default:
1045     return -1;
1046   case bitc::UNOP_FNEG:
1047     return IsFP ? Instruction::FNeg : -1;
1048   }
1049 }
1050 
1051 static int getDecodedBinaryOpcode(unsigned Val, Type *Ty) {
1052   bool IsFP = Ty->isFPOrFPVectorTy();
1053   // BinOps are only valid for int/fp or vector of int/fp types
1054   if (!IsFP && !Ty->isIntOrIntVectorTy())
1055     return -1;
1056 
1057   switch (Val) {
1058   default:
1059     return -1;
1060   case bitc::BINOP_ADD:
1061     return IsFP ? Instruction::FAdd : Instruction::Add;
1062   case bitc::BINOP_SUB:
1063     return IsFP ? Instruction::FSub : Instruction::Sub;
1064   case bitc::BINOP_MUL:
1065     return IsFP ? Instruction::FMul : Instruction::Mul;
1066   case bitc::BINOP_UDIV:
1067     return IsFP ? -1 : Instruction::UDiv;
1068   case bitc::BINOP_SDIV:
1069     return IsFP ? Instruction::FDiv : Instruction::SDiv;
1070   case bitc::BINOP_UREM:
1071     return IsFP ? -1 : Instruction::URem;
1072   case bitc::BINOP_SREM:
1073     return IsFP ? Instruction::FRem : Instruction::SRem;
1074   case bitc::BINOP_SHL:
1075     return IsFP ? -1 : Instruction::Shl;
1076   case bitc::BINOP_LSHR:
1077     return IsFP ? -1 : Instruction::LShr;
1078   case bitc::BINOP_ASHR:
1079     return IsFP ? -1 : Instruction::AShr;
1080   case bitc::BINOP_AND:
1081     return IsFP ? -1 : Instruction::And;
1082   case bitc::BINOP_OR:
1083     return IsFP ? -1 : Instruction::Or;
1084   case bitc::BINOP_XOR:
1085     return IsFP ? -1 : Instruction::Xor;
1086   }
1087 }
1088 
1089 static AtomicRMWInst::BinOp getDecodedRMWOperation(unsigned Val) {
1090   switch (Val) {
1091   default: return AtomicRMWInst::BAD_BINOP;
1092   case bitc::RMW_XCHG: return AtomicRMWInst::Xchg;
1093   case bitc::RMW_ADD: return AtomicRMWInst::Add;
1094   case bitc::RMW_SUB: return AtomicRMWInst::Sub;
1095   case bitc::RMW_AND: return AtomicRMWInst::And;
1096   case bitc::RMW_NAND: return AtomicRMWInst::Nand;
1097   case bitc::RMW_OR: return AtomicRMWInst::Or;
1098   case bitc::RMW_XOR: return AtomicRMWInst::Xor;
1099   case bitc::RMW_MAX: return AtomicRMWInst::Max;
1100   case bitc::RMW_MIN: return AtomicRMWInst::Min;
1101   case bitc::RMW_UMAX: return AtomicRMWInst::UMax;
1102   case bitc::RMW_UMIN: return AtomicRMWInst::UMin;
1103   case bitc::RMW_FADD: return AtomicRMWInst::FAdd;
1104   case bitc::RMW_FSUB: return AtomicRMWInst::FSub;
1105   }
1106 }
1107 
1108 static AtomicOrdering getDecodedOrdering(unsigned Val) {
1109   switch (Val) {
1110   case bitc::ORDERING_NOTATOMIC: return AtomicOrdering::NotAtomic;
1111   case bitc::ORDERING_UNORDERED: return AtomicOrdering::Unordered;
1112   case bitc::ORDERING_MONOTONIC: return AtomicOrdering::Monotonic;
1113   case bitc::ORDERING_ACQUIRE: return AtomicOrdering::Acquire;
1114   case bitc::ORDERING_RELEASE: return AtomicOrdering::Release;
1115   case bitc::ORDERING_ACQREL: return AtomicOrdering::AcquireRelease;
1116   default: // Map unknown orderings to sequentially-consistent.
1117   case bitc::ORDERING_SEQCST: return AtomicOrdering::SequentiallyConsistent;
1118   }
1119 }
1120 
1121 static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
1122   switch (Val) {
1123   default: // Map unknown selection kinds to any.
1124   case bitc::COMDAT_SELECTION_KIND_ANY:
1125     return Comdat::Any;
1126   case bitc::COMDAT_SELECTION_KIND_EXACT_MATCH:
1127     return Comdat::ExactMatch;
1128   case bitc::COMDAT_SELECTION_KIND_LARGEST:
1129     return Comdat::Largest;
1130   case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
1131     return Comdat::NoDeduplicate;
1132   case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
1133     return Comdat::SameSize;
1134   }
1135 }
1136 
1137 static FastMathFlags getDecodedFastMathFlags(unsigned Val) {
1138   FastMathFlags FMF;
1139   if (0 != (Val & bitc::UnsafeAlgebra))
1140     FMF.setFast();
1141   if (0 != (Val & bitc::AllowReassoc))
1142     FMF.setAllowReassoc();
1143   if (0 != (Val & bitc::NoNaNs))
1144     FMF.setNoNaNs();
1145   if (0 != (Val & bitc::NoInfs))
1146     FMF.setNoInfs();
1147   if (0 != (Val & bitc::NoSignedZeros))
1148     FMF.setNoSignedZeros();
1149   if (0 != (Val & bitc::AllowReciprocal))
1150     FMF.setAllowReciprocal();
1151   if (0 != (Val & bitc::AllowContract))
1152     FMF.setAllowContract(true);
1153   if (0 != (Val & bitc::ApproxFunc))
1154     FMF.setApproxFunc();
1155   return FMF;
1156 }
1157 
1158 static void upgradeDLLImportExportLinkage(GlobalValue *GV, unsigned Val) {
1159   switch (Val) {
1160   case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
1161   case 6: GV->setDLLStorageClass(GlobalValue::DLLExportStorageClass); break;
1162   }
1163 }
1164 
1165 Type *BitcodeReader::getTypeByID(unsigned ID) {
1166   // The type table size is always specified correctly.
1167   if (ID >= TypeList.size())
1168     return nullptr;
1169 
1170   if (Type *Ty = TypeList[ID])
1171     return Ty;
1172 
1173   // If we have a forward reference, the only possible case is when it is to a
1174   // named struct.  Just create a placeholder for now.
1175   return TypeList[ID] = createIdentifiedStructType(Context);
1176 }
1177 
1178 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context,
1179                                                       StringRef Name) {
1180   auto *Ret = StructType::create(Context, Name);
1181   IdentifiedStructTypes.push_back(Ret);
1182   return Ret;
1183 }
1184 
1185 StructType *BitcodeReader::createIdentifiedStructType(LLVMContext &Context) {
1186   auto *Ret = StructType::create(Context);
1187   IdentifiedStructTypes.push_back(Ret);
1188   return Ret;
1189 }
1190 
1191 //===----------------------------------------------------------------------===//
1192 //  Functions for parsing blocks from the bitcode file
1193 //===----------------------------------------------------------------------===//
1194 
1195 static uint64_t getRawAttributeMask(Attribute::AttrKind Val) {
1196   switch (Val) {
1197   case Attribute::EndAttrKinds:
1198   case Attribute::EmptyKey:
1199   case Attribute::TombstoneKey:
1200     llvm_unreachable("Synthetic enumerators which should never get here");
1201 
1202   case Attribute::None:            return 0;
1203   case Attribute::ZExt:            return 1 << 0;
1204   case Attribute::SExt:            return 1 << 1;
1205   case Attribute::NoReturn:        return 1 << 2;
1206   case Attribute::InReg:           return 1 << 3;
1207   case Attribute::StructRet:       return 1 << 4;
1208   case Attribute::NoUnwind:        return 1 << 5;
1209   case Attribute::NoAlias:         return 1 << 6;
1210   case Attribute::ByVal:           return 1 << 7;
1211   case Attribute::Nest:            return 1 << 8;
1212   case Attribute::ReadNone:        return 1 << 9;
1213   case Attribute::ReadOnly:        return 1 << 10;
1214   case Attribute::NoInline:        return 1 << 11;
1215   case Attribute::AlwaysInline:    return 1 << 12;
1216   case Attribute::OptimizeForSize: return 1 << 13;
1217   case Attribute::StackProtect:    return 1 << 14;
1218   case Attribute::StackProtectReq: return 1 << 15;
1219   case Attribute::Alignment:       return 31 << 16;
1220   case Attribute::NoCapture:       return 1 << 21;
1221   case Attribute::NoRedZone:       return 1 << 22;
1222   case Attribute::NoImplicitFloat: return 1 << 23;
1223   case Attribute::Naked:           return 1 << 24;
1224   case Attribute::InlineHint:      return 1 << 25;
1225   case Attribute::StackAlignment:  return 7 << 26;
1226   case Attribute::ReturnsTwice:    return 1 << 29;
1227   case Attribute::UWTable:         return 1 << 30;
1228   case Attribute::NonLazyBind:     return 1U << 31;
1229   case Attribute::SanitizeAddress: return 1ULL << 32;
1230   case Attribute::MinSize:         return 1ULL << 33;
1231   case Attribute::NoDuplicate:     return 1ULL << 34;
1232   case Attribute::StackProtectStrong: return 1ULL << 35;
1233   case Attribute::SanitizeThread:  return 1ULL << 36;
1234   case Attribute::SanitizeMemory:  return 1ULL << 37;
1235   case Attribute::NoBuiltin:       return 1ULL << 38;
1236   case Attribute::Returned:        return 1ULL << 39;
1237   case Attribute::Cold:            return 1ULL << 40;
1238   case Attribute::Builtin:         return 1ULL << 41;
1239   case Attribute::OptimizeNone:    return 1ULL << 42;
1240   case Attribute::InAlloca:        return 1ULL << 43;
1241   case Attribute::NonNull:         return 1ULL << 44;
1242   case Attribute::JumpTable:       return 1ULL << 45;
1243   case Attribute::Convergent:      return 1ULL << 46;
1244   case Attribute::SafeStack:       return 1ULL << 47;
1245   case Attribute::NoRecurse:       return 1ULL << 48;
1246   case Attribute::InaccessibleMemOnly:         return 1ULL << 49;
1247   case Attribute::InaccessibleMemOrArgMemOnly: return 1ULL << 50;
1248   case Attribute::SwiftSelf:       return 1ULL << 51;
1249   case Attribute::SwiftError:      return 1ULL << 52;
1250   case Attribute::WriteOnly:       return 1ULL << 53;
1251   case Attribute::Speculatable:    return 1ULL << 54;
1252   case Attribute::StrictFP:        return 1ULL << 55;
1253   case Attribute::SanitizeHWAddress: return 1ULL << 56;
1254   case Attribute::NoCfCheck:       return 1ULL << 57;
1255   case Attribute::OptForFuzzing:   return 1ULL << 58;
1256   case Attribute::ShadowCallStack: return 1ULL << 59;
1257   case Attribute::SpeculativeLoadHardening:
1258     return 1ULL << 60;
1259   case Attribute::ImmArg:
1260     return 1ULL << 61;
1261   case Attribute::WillReturn:
1262     return 1ULL << 62;
1263   case Attribute::NoFree:
1264     return 1ULL << 63;
1265   default:
1266     // Other attributes are not supported in the raw format,
1267     // as we ran out of space.
1268     return 0;
1269   }
1270   llvm_unreachable("Unsupported attribute type");
1271 }
1272 
1273 static void addRawAttributeValue(AttrBuilder &B, uint64_t Val) {
1274   if (!Val) return;
1275 
1276   for (Attribute::AttrKind I = Attribute::None; I != Attribute::EndAttrKinds;
1277        I = Attribute::AttrKind(I + 1)) {
1278     if (uint64_t A = (Val & getRawAttributeMask(I))) {
1279       if (I == Attribute::Alignment)
1280         B.addAlignmentAttr(1ULL << ((A >> 16) - 1));
1281       else if (I == Attribute::StackAlignment)
1282         B.addStackAlignmentAttr(1ULL << ((A >> 26)-1));
1283       else if (Attribute::isTypeAttrKind(I))
1284         B.addTypeAttr(I, nullptr); // Type will be auto-upgraded.
1285       else
1286         B.addAttribute(I);
1287     }
1288   }
1289 }
1290 
1291 /// This fills an AttrBuilder object with the LLVM attributes that have
1292 /// been decoded from the given integer. This function must stay in sync with
1293 /// 'encodeLLVMAttributesForBitcode'.
1294 static void decodeLLVMAttributesForBitcode(AttrBuilder &B,
1295                                            uint64_t EncodedAttrs) {
1296   // The alignment is stored as a 16-bit raw value from bits 31--16.  We shift
1297   // the bits above 31 down by 11 bits.
1298   unsigned Alignment = (EncodedAttrs & (0xffffULL << 16)) >> 16;
1299   assert((!Alignment || isPowerOf2_32(Alignment)) &&
1300          "Alignment must be a power of two.");
1301 
1302   if (Alignment)
1303     B.addAlignmentAttr(Alignment);
1304   addRawAttributeValue(B, ((EncodedAttrs & (0xfffffULL << 32)) >> 11) |
1305                           (EncodedAttrs & 0xffff));
1306 }
1307 
1308 Error BitcodeReader::parseAttributeBlock() {
1309   if (Error Err = Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID))
1310     return Err;
1311 
1312   if (!MAttributes.empty())
1313     return error("Invalid multiple blocks");
1314 
1315   SmallVector<uint64_t, 64> Record;
1316 
1317   SmallVector<AttributeList, 8> Attrs;
1318 
1319   // Read all the records.
1320   while (true) {
1321     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
1322     if (!MaybeEntry)
1323       return MaybeEntry.takeError();
1324     BitstreamEntry Entry = MaybeEntry.get();
1325 
1326     switch (Entry.Kind) {
1327     case BitstreamEntry::SubBlock: // Handled for us already.
1328     case BitstreamEntry::Error:
1329       return error("Malformed block");
1330     case BitstreamEntry::EndBlock:
1331       return Error::success();
1332     case BitstreamEntry::Record:
1333       // The interesting case.
1334       break;
1335     }
1336 
1337     // Read a record.
1338     Record.clear();
1339     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
1340     if (!MaybeRecord)
1341       return MaybeRecord.takeError();
1342     switch (MaybeRecord.get()) {
1343     default:  // Default behavior: ignore.
1344       break;
1345     case bitc::PARAMATTR_CODE_ENTRY_OLD: // ENTRY: [paramidx0, attr0, ...]
1346       // Deprecated, but still needed to read old bitcode files.
1347       if (Record.size() & 1)
1348         return error("Invalid record");
1349 
1350       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
1351         AttrBuilder B;
1352         decodeLLVMAttributesForBitcode(B, Record[i+1]);
1353         Attrs.push_back(AttributeList::get(Context, Record[i], B));
1354       }
1355 
1356       MAttributes.push_back(AttributeList::get(Context, Attrs));
1357       Attrs.clear();
1358       break;
1359     case bitc::PARAMATTR_CODE_ENTRY: // ENTRY: [attrgrp0, attrgrp1, ...]
1360       for (unsigned i = 0, e = Record.size(); i != e; ++i)
1361         Attrs.push_back(MAttributeGroups[Record[i]]);
1362 
1363       MAttributes.push_back(AttributeList::get(Context, Attrs));
1364       Attrs.clear();
1365       break;
1366     }
1367   }
1368 }
1369 
1370 // Returns Attribute::None on unrecognized codes.
1371 static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
1372   switch (Code) {
1373   default:
1374     return Attribute::None;
1375   case bitc::ATTR_KIND_ALIGNMENT:
1376     return Attribute::Alignment;
1377   case bitc::ATTR_KIND_ALWAYS_INLINE:
1378     return Attribute::AlwaysInline;
1379   case bitc::ATTR_KIND_ARGMEMONLY:
1380     return Attribute::ArgMemOnly;
1381   case bitc::ATTR_KIND_BUILTIN:
1382     return Attribute::Builtin;
1383   case bitc::ATTR_KIND_BY_VAL:
1384     return Attribute::ByVal;
1385   case bitc::ATTR_KIND_IN_ALLOCA:
1386     return Attribute::InAlloca;
1387   case bitc::ATTR_KIND_COLD:
1388     return Attribute::Cold;
1389   case bitc::ATTR_KIND_CONVERGENT:
1390     return Attribute::Convergent;
1391   case bitc::ATTR_KIND_ELEMENTTYPE:
1392     return Attribute::ElementType;
1393   case bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY:
1394     return Attribute::InaccessibleMemOnly;
1395   case bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY:
1396     return Attribute::InaccessibleMemOrArgMemOnly;
1397   case bitc::ATTR_KIND_INLINE_HINT:
1398     return Attribute::InlineHint;
1399   case bitc::ATTR_KIND_IN_REG:
1400     return Attribute::InReg;
1401   case bitc::ATTR_KIND_JUMP_TABLE:
1402     return Attribute::JumpTable;
1403   case bitc::ATTR_KIND_MIN_SIZE:
1404     return Attribute::MinSize;
1405   case bitc::ATTR_KIND_NAKED:
1406     return Attribute::Naked;
1407   case bitc::ATTR_KIND_NEST:
1408     return Attribute::Nest;
1409   case bitc::ATTR_KIND_NO_ALIAS:
1410     return Attribute::NoAlias;
1411   case bitc::ATTR_KIND_NO_BUILTIN:
1412     return Attribute::NoBuiltin;
1413   case bitc::ATTR_KIND_NO_CALLBACK:
1414     return Attribute::NoCallback;
1415   case bitc::ATTR_KIND_NO_CAPTURE:
1416     return Attribute::NoCapture;
1417   case bitc::ATTR_KIND_NO_DUPLICATE:
1418     return Attribute::NoDuplicate;
1419   case bitc::ATTR_KIND_NOFREE:
1420     return Attribute::NoFree;
1421   case bitc::ATTR_KIND_NO_IMPLICIT_FLOAT:
1422     return Attribute::NoImplicitFloat;
1423   case bitc::ATTR_KIND_NO_INLINE:
1424     return Attribute::NoInline;
1425   case bitc::ATTR_KIND_NO_RECURSE:
1426     return Attribute::NoRecurse;
1427   case bitc::ATTR_KIND_NO_MERGE:
1428     return Attribute::NoMerge;
1429   case bitc::ATTR_KIND_NON_LAZY_BIND:
1430     return Attribute::NonLazyBind;
1431   case bitc::ATTR_KIND_NON_NULL:
1432     return Attribute::NonNull;
1433   case bitc::ATTR_KIND_DEREFERENCEABLE:
1434     return Attribute::Dereferenceable;
1435   case bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL:
1436     return Attribute::DereferenceableOrNull;
1437   case bitc::ATTR_KIND_ALLOC_SIZE:
1438     return Attribute::AllocSize;
1439   case bitc::ATTR_KIND_NO_RED_ZONE:
1440     return Attribute::NoRedZone;
1441   case bitc::ATTR_KIND_NO_RETURN:
1442     return Attribute::NoReturn;
1443   case bitc::ATTR_KIND_NOSYNC:
1444     return Attribute::NoSync;
1445   case bitc::ATTR_KIND_NOCF_CHECK:
1446     return Attribute::NoCfCheck;
1447   case bitc::ATTR_KIND_NO_PROFILE:
1448     return Attribute::NoProfile;
1449   case bitc::ATTR_KIND_NO_UNWIND:
1450     return Attribute::NoUnwind;
1451   case bitc::ATTR_KIND_NO_SANITIZE_COVERAGE:
1452     return Attribute::NoSanitizeCoverage;
1453   case bitc::ATTR_KIND_NULL_POINTER_IS_VALID:
1454     return Attribute::NullPointerIsValid;
1455   case bitc::ATTR_KIND_OPT_FOR_FUZZING:
1456     return Attribute::OptForFuzzing;
1457   case bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE:
1458     return Attribute::OptimizeForSize;
1459   case bitc::ATTR_KIND_OPTIMIZE_NONE:
1460     return Attribute::OptimizeNone;
1461   case bitc::ATTR_KIND_READ_NONE:
1462     return Attribute::ReadNone;
1463   case bitc::ATTR_KIND_READ_ONLY:
1464     return Attribute::ReadOnly;
1465   case bitc::ATTR_KIND_RETURNED:
1466     return Attribute::Returned;
1467   case bitc::ATTR_KIND_RETURNS_TWICE:
1468     return Attribute::ReturnsTwice;
1469   case bitc::ATTR_KIND_S_EXT:
1470     return Attribute::SExt;
1471   case bitc::ATTR_KIND_SPECULATABLE:
1472     return Attribute::Speculatable;
1473   case bitc::ATTR_KIND_STACK_ALIGNMENT:
1474     return Attribute::StackAlignment;
1475   case bitc::ATTR_KIND_STACK_PROTECT:
1476     return Attribute::StackProtect;
1477   case bitc::ATTR_KIND_STACK_PROTECT_REQ:
1478     return Attribute::StackProtectReq;
1479   case bitc::ATTR_KIND_STACK_PROTECT_STRONG:
1480     return Attribute::StackProtectStrong;
1481   case bitc::ATTR_KIND_SAFESTACK:
1482     return Attribute::SafeStack;
1483   case bitc::ATTR_KIND_SHADOWCALLSTACK:
1484     return Attribute::ShadowCallStack;
1485   case bitc::ATTR_KIND_STRICT_FP:
1486     return Attribute::StrictFP;
1487   case bitc::ATTR_KIND_STRUCT_RET:
1488     return Attribute::StructRet;
1489   case bitc::ATTR_KIND_SANITIZE_ADDRESS:
1490     return Attribute::SanitizeAddress;
1491   case bitc::ATTR_KIND_SANITIZE_HWADDRESS:
1492     return Attribute::SanitizeHWAddress;
1493   case bitc::ATTR_KIND_SANITIZE_THREAD:
1494     return Attribute::SanitizeThread;
1495   case bitc::ATTR_KIND_SANITIZE_MEMORY:
1496     return Attribute::SanitizeMemory;
1497   case bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING:
1498     return Attribute::SpeculativeLoadHardening;
1499   case bitc::ATTR_KIND_SWIFT_ERROR:
1500     return Attribute::SwiftError;
1501   case bitc::ATTR_KIND_SWIFT_SELF:
1502     return Attribute::SwiftSelf;
1503   case bitc::ATTR_KIND_SWIFT_ASYNC:
1504     return Attribute::SwiftAsync;
1505   case bitc::ATTR_KIND_UW_TABLE:
1506     return Attribute::UWTable;
1507   case bitc::ATTR_KIND_VSCALE_RANGE:
1508     return Attribute::VScaleRange;
1509   case bitc::ATTR_KIND_WILLRETURN:
1510     return Attribute::WillReturn;
1511   case bitc::ATTR_KIND_WRITEONLY:
1512     return Attribute::WriteOnly;
1513   case bitc::ATTR_KIND_Z_EXT:
1514     return Attribute::ZExt;
1515   case bitc::ATTR_KIND_IMMARG:
1516     return Attribute::ImmArg;
1517   case bitc::ATTR_KIND_SANITIZE_MEMTAG:
1518     return Attribute::SanitizeMemTag;
1519   case bitc::ATTR_KIND_PREALLOCATED:
1520     return Attribute::Preallocated;
1521   case bitc::ATTR_KIND_NOUNDEF:
1522     return Attribute::NoUndef;
1523   case bitc::ATTR_KIND_BYREF:
1524     return Attribute::ByRef;
1525   case bitc::ATTR_KIND_MUSTPROGRESS:
1526     return Attribute::MustProgress;
1527   case bitc::ATTR_KIND_HOT:
1528     return Attribute::Hot;
1529   }
1530 }
1531 
1532 Error BitcodeReader::parseAlignmentValue(uint64_t Exponent,
1533                                          MaybeAlign &Alignment) {
1534   // Note: Alignment in bitcode files is incremented by 1, so that zero
1535   // can be used for default alignment.
1536   if (Exponent > Value::MaxAlignmentExponent + 1)
1537     return error("Invalid alignment value");
1538   Alignment = decodeMaybeAlign(Exponent);
1539   return Error::success();
1540 }
1541 
1542 Error BitcodeReader::parseAttrKind(uint64_t Code, Attribute::AttrKind *Kind) {
1543   *Kind = getAttrFromCode(Code);
1544   if (*Kind == Attribute::None)
1545     return error("Unknown attribute kind (" + Twine(Code) + ")");
1546   return Error::success();
1547 }
1548 
1549 Error BitcodeReader::parseAttributeGroupBlock() {
1550   if (Error Err = Stream.EnterSubBlock(bitc::PARAMATTR_GROUP_BLOCK_ID))
1551     return Err;
1552 
1553   if (!MAttributeGroups.empty())
1554     return error("Invalid multiple blocks");
1555 
1556   SmallVector<uint64_t, 64> Record;
1557 
1558   // Read all the records.
1559   while (true) {
1560     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
1561     if (!MaybeEntry)
1562       return MaybeEntry.takeError();
1563     BitstreamEntry Entry = MaybeEntry.get();
1564 
1565     switch (Entry.Kind) {
1566     case BitstreamEntry::SubBlock: // Handled for us already.
1567     case BitstreamEntry::Error:
1568       return error("Malformed block");
1569     case BitstreamEntry::EndBlock:
1570       return Error::success();
1571     case BitstreamEntry::Record:
1572       // The interesting case.
1573       break;
1574     }
1575 
1576     // Read a record.
1577     Record.clear();
1578     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
1579     if (!MaybeRecord)
1580       return MaybeRecord.takeError();
1581     switch (MaybeRecord.get()) {
1582     default:  // Default behavior: ignore.
1583       break;
1584     case bitc::PARAMATTR_GRP_CODE_ENTRY: { // ENTRY: [grpid, idx, a0, a1, ...]
1585       if (Record.size() < 3)
1586         return error("Invalid record");
1587 
1588       uint64_t GrpID = Record[0];
1589       uint64_t Idx = Record[1]; // Index of the object this attribute refers to.
1590 
1591       AttrBuilder B;
1592       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
1593         if (Record[i] == 0) {        // Enum attribute
1594           Attribute::AttrKind Kind;
1595           if (Error Err = parseAttrKind(Record[++i], &Kind))
1596             return Err;
1597 
1598           // Upgrade old-style byval attribute to one with a type, even if it's
1599           // nullptr. We will have to insert the real type when we associate
1600           // this AttributeList with a function.
1601           if (Kind == Attribute::ByVal)
1602             B.addByValAttr(nullptr);
1603           else if (Kind == Attribute::StructRet)
1604             B.addStructRetAttr(nullptr);
1605           else if (Kind == Attribute::InAlloca)
1606             B.addInAllocaAttr(nullptr);
1607           else if (Attribute::isEnumAttrKind(Kind))
1608             B.addAttribute(Kind);
1609           else
1610             return error("Not an enum attribute");
1611         } else if (Record[i] == 1) { // Integer attribute
1612           Attribute::AttrKind Kind;
1613           if (Error Err = parseAttrKind(Record[++i], &Kind))
1614             return Err;
1615           if (!Attribute::isIntAttrKind(Kind))
1616             return error("Not an int attribute");
1617           if (Kind == Attribute::Alignment)
1618             B.addAlignmentAttr(Record[++i]);
1619           else if (Kind == Attribute::StackAlignment)
1620             B.addStackAlignmentAttr(Record[++i]);
1621           else if (Kind == Attribute::Dereferenceable)
1622             B.addDereferenceableAttr(Record[++i]);
1623           else if (Kind == Attribute::DereferenceableOrNull)
1624             B.addDereferenceableOrNullAttr(Record[++i]);
1625           else if (Kind == Attribute::AllocSize)
1626             B.addAllocSizeAttrFromRawRepr(Record[++i]);
1627           else if (Kind == Attribute::VScaleRange)
1628             B.addVScaleRangeAttrFromRawRepr(Record[++i]);
1629         } else if (Record[i] == 3 || Record[i] == 4) { // String attribute
1630           bool HasValue = (Record[i++] == 4);
1631           SmallString<64> KindStr;
1632           SmallString<64> ValStr;
1633 
1634           while (Record[i] != 0 && i != e)
1635             KindStr += Record[i++];
1636           assert(Record[i] == 0 && "Kind string not null terminated");
1637 
1638           if (HasValue) {
1639             // Has a value associated with it.
1640             ++i; // Skip the '0' that terminates the "kind" string.
1641             while (Record[i] != 0 && i != e)
1642               ValStr += Record[i++];
1643             assert(Record[i] == 0 && "Value string not null terminated");
1644           }
1645 
1646           B.addAttribute(KindStr.str(), ValStr.str());
1647         } else {
1648           assert((Record[i] == 5 || Record[i] == 6) &&
1649                  "Invalid attribute group entry");
1650           bool HasType = Record[i] == 6;
1651           Attribute::AttrKind Kind;
1652           if (Error Err = parseAttrKind(Record[++i], &Kind))
1653             return Err;
1654           if (!Attribute::isTypeAttrKind(Kind))
1655             return error("Not a type attribute");
1656 
1657           B.addTypeAttr(Kind, HasType ? getTypeByID(Record[++i]) : nullptr);
1658         }
1659       }
1660 
1661       UpgradeAttributes(B);
1662       MAttributeGroups[GrpID] = AttributeList::get(Context, Idx, B);
1663       break;
1664     }
1665     }
1666   }
1667 }
1668 
1669 Error BitcodeReader::parseTypeTable() {
1670   if (Error Err = Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
1671     return Err;
1672 
1673   return parseTypeTableBody();
1674 }
1675 
1676 Error BitcodeReader::parseTypeTableBody() {
1677   if (!TypeList.empty())
1678     return error("Invalid multiple blocks");
1679 
1680   SmallVector<uint64_t, 64> Record;
1681   unsigned NumRecords = 0;
1682 
1683   SmallString<64> TypeName;
1684 
1685   // Read all the records for this type table.
1686   while (true) {
1687     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
1688     if (!MaybeEntry)
1689       return MaybeEntry.takeError();
1690     BitstreamEntry Entry = MaybeEntry.get();
1691 
1692     switch (Entry.Kind) {
1693     case BitstreamEntry::SubBlock: // Handled for us already.
1694     case BitstreamEntry::Error:
1695       return error("Malformed block");
1696     case BitstreamEntry::EndBlock:
1697       if (NumRecords != TypeList.size())
1698         return error("Malformed block");
1699       return Error::success();
1700     case BitstreamEntry::Record:
1701       // The interesting case.
1702       break;
1703     }
1704 
1705     // Read a record.
1706     Record.clear();
1707     Type *ResultTy = nullptr;
1708     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
1709     if (!MaybeRecord)
1710       return MaybeRecord.takeError();
1711     switch (MaybeRecord.get()) {
1712     default:
1713       return error("Invalid value");
1714     case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
1715       // TYPE_CODE_NUMENTRY contains a count of the number of types in the
1716       // type list.  This allows us to reserve space.
1717       if (Record.empty())
1718         return error("Invalid record");
1719       TypeList.resize(Record[0]);
1720       continue;
1721     case bitc::TYPE_CODE_VOID:      // VOID
1722       ResultTy = Type::getVoidTy(Context);
1723       break;
1724     case bitc::TYPE_CODE_HALF:     // HALF
1725       ResultTy = Type::getHalfTy(Context);
1726       break;
1727     case bitc::TYPE_CODE_BFLOAT:    // BFLOAT
1728       ResultTy = Type::getBFloatTy(Context);
1729       break;
1730     case bitc::TYPE_CODE_FLOAT:     // FLOAT
1731       ResultTy = Type::getFloatTy(Context);
1732       break;
1733     case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
1734       ResultTy = Type::getDoubleTy(Context);
1735       break;
1736     case bitc::TYPE_CODE_X86_FP80:  // X86_FP80
1737       ResultTy = Type::getX86_FP80Ty(Context);
1738       break;
1739     case bitc::TYPE_CODE_FP128:     // FP128
1740       ResultTy = Type::getFP128Ty(Context);
1741       break;
1742     case bitc::TYPE_CODE_PPC_FP128: // PPC_FP128
1743       ResultTy = Type::getPPC_FP128Ty(Context);
1744       break;
1745     case bitc::TYPE_CODE_LABEL:     // LABEL
1746       ResultTy = Type::getLabelTy(Context);
1747       break;
1748     case bitc::TYPE_CODE_METADATA:  // METADATA
1749       ResultTy = Type::getMetadataTy(Context);
1750       break;
1751     case bitc::TYPE_CODE_X86_MMX:   // X86_MMX
1752       ResultTy = Type::getX86_MMXTy(Context);
1753       break;
1754     case bitc::TYPE_CODE_X86_AMX:   // X86_AMX
1755       ResultTy = Type::getX86_AMXTy(Context);
1756       break;
1757     case bitc::TYPE_CODE_TOKEN:     // TOKEN
1758       ResultTy = Type::getTokenTy(Context);
1759       break;
1760     case bitc::TYPE_CODE_INTEGER: { // INTEGER: [width]
1761       if (Record.empty())
1762         return error("Invalid record");
1763 
1764       uint64_t NumBits = Record[0];
1765       if (NumBits < IntegerType::MIN_INT_BITS ||
1766           NumBits > IntegerType::MAX_INT_BITS)
1767         return error("Bitwidth for integer type out of range");
1768       ResultTy = IntegerType::get(Context, NumBits);
1769       break;
1770     }
1771     case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
1772                                     //          [pointee type, address space]
1773       if (Record.empty())
1774         return error("Invalid record");
1775       unsigned AddressSpace = 0;
1776       if (Record.size() == 2)
1777         AddressSpace = Record[1];
1778       ResultTy = getTypeByID(Record[0]);
1779       if (!ResultTy ||
1780           !PointerType::isValidElementType(ResultTy))
1781         return error("Invalid type");
1782       ResultTy = PointerType::get(ResultTy, AddressSpace);
1783       break;
1784     }
1785     case bitc::TYPE_CODE_OPAQUE_POINTER: { // OPAQUE_POINTER: [addrspace]
1786       if (Record.size() != 1)
1787         return error("Invalid record");
1788       unsigned AddressSpace = Record[0];
1789       ResultTy = PointerType::get(Context, AddressSpace);
1790       break;
1791     }
1792     case bitc::TYPE_CODE_FUNCTION_OLD: {
1793       // Deprecated, but still needed to read old bitcode files.
1794       // FUNCTION: [vararg, attrid, retty, paramty x N]
1795       if (Record.size() < 3)
1796         return error("Invalid record");
1797       SmallVector<Type*, 8> ArgTys;
1798       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
1799         if (Type *T = getTypeByID(Record[i]))
1800           ArgTys.push_back(T);
1801         else
1802           break;
1803       }
1804 
1805       ResultTy = getTypeByID(Record[2]);
1806       if (!ResultTy || ArgTys.size() < Record.size()-3)
1807         return error("Invalid type");
1808 
1809       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1810       break;
1811     }
1812     case bitc::TYPE_CODE_FUNCTION: {
1813       // FUNCTION: [vararg, retty, paramty x N]
1814       if (Record.size() < 2)
1815         return error("Invalid record");
1816       SmallVector<Type*, 8> ArgTys;
1817       for (unsigned i = 2, e = Record.size(); i != e; ++i) {
1818         if (Type *T = getTypeByID(Record[i])) {
1819           if (!FunctionType::isValidArgumentType(T))
1820             return error("Invalid function argument type");
1821           ArgTys.push_back(T);
1822         }
1823         else
1824           break;
1825       }
1826 
1827       ResultTy = getTypeByID(Record[1]);
1828       if (!ResultTy || ArgTys.size() < Record.size()-2)
1829         return error("Invalid type");
1830 
1831       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
1832       break;
1833     }
1834     case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
1835       if (Record.empty())
1836         return error("Invalid record");
1837       SmallVector<Type*, 8> EltTys;
1838       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1839         if (Type *T = getTypeByID(Record[i]))
1840           EltTys.push_back(T);
1841         else
1842           break;
1843       }
1844       if (EltTys.size() != Record.size()-1)
1845         return error("Invalid type");
1846       ResultTy = StructType::get(Context, EltTys, Record[0]);
1847       break;
1848     }
1849     case bitc::TYPE_CODE_STRUCT_NAME:   // STRUCT_NAME: [strchr x N]
1850       if (convertToString(Record, 0, TypeName))
1851         return error("Invalid record");
1852       continue;
1853 
1854     case bitc::TYPE_CODE_STRUCT_NAMED: { // STRUCT: [ispacked, eltty x N]
1855       if (Record.empty())
1856         return error("Invalid record");
1857 
1858       if (NumRecords >= TypeList.size())
1859         return error("Invalid TYPE table");
1860 
1861       // Check to see if this was forward referenced, if so fill in the temp.
1862       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1863       if (Res) {
1864         Res->setName(TypeName);
1865         TypeList[NumRecords] = nullptr;
1866       } else  // Otherwise, create a new struct.
1867         Res = createIdentifiedStructType(Context, TypeName);
1868       TypeName.clear();
1869 
1870       SmallVector<Type*, 8> EltTys;
1871       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
1872         if (Type *T = getTypeByID(Record[i]))
1873           EltTys.push_back(T);
1874         else
1875           break;
1876       }
1877       if (EltTys.size() != Record.size()-1)
1878         return error("Invalid record");
1879       Res->setBody(EltTys, Record[0]);
1880       ResultTy = Res;
1881       break;
1882     }
1883     case bitc::TYPE_CODE_OPAQUE: {       // OPAQUE: []
1884       if (Record.size() != 1)
1885         return error("Invalid record");
1886 
1887       if (NumRecords >= TypeList.size())
1888         return error("Invalid TYPE table");
1889 
1890       // Check to see if this was forward referenced, if so fill in the temp.
1891       StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
1892       if (Res) {
1893         Res->setName(TypeName);
1894         TypeList[NumRecords] = nullptr;
1895       } else  // Otherwise, create a new struct with no body.
1896         Res = createIdentifiedStructType(Context, TypeName);
1897       TypeName.clear();
1898       ResultTy = Res;
1899       break;
1900     }
1901     case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
1902       if (Record.size() < 2)
1903         return error("Invalid record");
1904       ResultTy = getTypeByID(Record[1]);
1905       if (!ResultTy || !ArrayType::isValidElementType(ResultTy))
1906         return error("Invalid type");
1907       ResultTy = ArrayType::get(ResultTy, Record[0]);
1908       break;
1909     case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty] or
1910                                     //         [numelts, eltty, scalable]
1911       if (Record.size() < 2)
1912         return error("Invalid record");
1913       if (Record[0] == 0)
1914         return error("Invalid vector length");
1915       ResultTy = getTypeByID(Record[1]);
1916       if (!ResultTy || !StructType::isValidElementType(ResultTy))
1917         return error("Invalid type");
1918       bool Scalable = Record.size() > 2 ? Record[2] : false;
1919       ResultTy = VectorType::get(ResultTy, Record[0], Scalable);
1920       break;
1921     }
1922 
1923     if (NumRecords >= TypeList.size())
1924       return error("Invalid TYPE table");
1925     if (TypeList[NumRecords])
1926       return error(
1927           "Invalid TYPE table: Only named structs can be forward referenced");
1928     assert(ResultTy && "Didn't read a type?");
1929     TypeList[NumRecords++] = ResultTy;
1930   }
1931 }
1932 
1933 Error BitcodeReader::parseOperandBundleTags() {
1934   if (Error Err = Stream.EnterSubBlock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID))
1935     return Err;
1936 
1937   if (!BundleTags.empty())
1938     return error("Invalid multiple blocks");
1939 
1940   SmallVector<uint64_t, 64> Record;
1941 
1942   while (true) {
1943     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
1944     if (!MaybeEntry)
1945       return MaybeEntry.takeError();
1946     BitstreamEntry Entry = MaybeEntry.get();
1947 
1948     switch (Entry.Kind) {
1949     case BitstreamEntry::SubBlock: // Handled for us already.
1950     case BitstreamEntry::Error:
1951       return error("Malformed block");
1952     case BitstreamEntry::EndBlock:
1953       return Error::success();
1954     case BitstreamEntry::Record:
1955       // The interesting case.
1956       break;
1957     }
1958 
1959     // Tags are implicitly mapped to integers by their order.
1960 
1961     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
1962     if (!MaybeRecord)
1963       return MaybeRecord.takeError();
1964     if (MaybeRecord.get() != bitc::OPERAND_BUNDLE_TAG)
1965       return error("Invalid record");
1966 
1967     // OPERAND_BUNDLE_TAG: [strchr x N]
1968     BundleTags.emplace_back();
1969     if (convertToString(Record, 0, BundleTags.back()))
1970       return error("Invalid record");
1971     Record.clear();
1972   }
1973 }
1974 
1975 Error BitcodeReader::parseSyncScopeNames() {
1976   if (Error Err = Stream.EnterSubBlock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID))
1977     return Err;
1978 
1979   if (!SSIDs.empty())
1980     return error("Invalid multiple synchronization scope names blocks");
1981 
1982   SmallVector<uint64_t, 64> Record;
1983   while (true) {
1984     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
1985     if (!MaybeEntry)
1986       return MaybeEntry.takeError();
1987     BitstreamEntry Entry = MaybeEntry.get();
1988 
1989     switch (Entry.Kind) {
1990     case BitstreamEntry::SubBlock: // Handled for us already.
1991     case BitstreamEntry::Error:
1992       return error("Malformed block");
1993     case BitstreamEntry::EndBlock:
1994       if (SSIDs.empty())
1995         return error("Invalid empty synchronization scope names block");
1996       return Error::success();
1997     case BitstreamEntry::Record:
1998       // The interesting case.
1999       break;
2000     }
2001 
2002     // Synchronization scope names are implicitly mapped to synchronization
2003     // scope IDs by their order.
2004 
2005     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
2006     if (!MaybeRecord)
2007       return MaybeRecord.takeError();
2008     if (MaybeRecord.get() != bitc::SYNC_SCOPE_NAME)
2009       return error("Invalid record");
2010 
2011     SmallString<16> SSN;
2012     if (convertToString(Record, 0, SSN))
2013       return error("Invalid record");
2014 
2015     SSIDs.push_back(Context.getOrInsertSyncScopeID(SSN));
2016     Record.clear();
2017   }
2018 }
2019 
2020 /// Associate a value with its name from the given index in the provided record.
2021 Expected<Value *> BitcodeReader::recordValue(SmallVectorImpl<uint64_t> &Record,
2022                                              unsigned NameIndex, Triple &TT) {
2023   SmallString<128> ValueName;
2024   if (convertToString(Record, NameIndex, ValueName))
2025     return error("Invalid record");
2026   unsigned ValueID = Record[0];
2027   if (ValueID >= ValueList.size() || !ValueList[ValueID])
2028     return error("Invalid record");
2029   Value *V = ValueList[ValueID];
2030 
2031   StringRef NameStr(ValueName.data(), ValueName.size());
2032   if (NameStr.find_first_of(0) != StringRef::npos)
2033     return error("Invalid value name");
2034   V->setName(NameStr);
2035   auto *GO = dyn_cast<GlobalObject>(V);
2036   if (GO) {
2037     if (GO->getComdat() == reinterpret_cast<Comdat *>(1)) {
2038       if (TT.supportsCOMDAT())
2039         GO->setComdat(TheModule->getOrInsertComdat(V->getName()));
2040       else
2041         GO->setComdat(nullptr);
2042     }
2043   }
2044   return V;
2045 }
2046 
2047 /// Helper to note and return the current location, and jump to the given
2048 /// offset.
2049 static Expected<uint64_t> jumpToValueSymbolTable(uint64_t Offset,
2050                                                  BitstreamCursor &Stream) {
2051   // Save the current parsing location so we can jump back at the end
2052   // of the VST read.
2053   uint64_t CurrentBit = Stream.GetCurrentBitNo();
2054   if (Error JumpFailed = Stream.JumpToBit(Offset * 32))
2055     return std::move(JumpFailed);
2056   Expected<BitstreamEntry> MaybeEntry = Stream.advance();
2057   if (!MaybeEntry)
2058     return MaybeEntry.takeError();
2059   assert(MaybeEntry.get().Kind == BitstreamEntry::SubBlock);
2060   assert(MaybeEntry.get().ID == bitc::VALUE_SYMTAB_BLOCK_ID);
2061   return CurrentBit;
2062 }
2063 
2064 void BitcodeReader::setDeferredFunctionInfo(unsigned FuncBitcodeOffsetDelta,
2065                                             Function *F,
2066                                             ArrayRef<uint64_t> Record) {
2067   // Note that we subtract 1 here because the offset is relative to one word
2068   // before the start of the identification or module block, which was
2069   // historically always the start of the regular bitcode header.
2070   uint64_t FuncWordOffset = Record[1] - 1;
2071   uint64_t FuncBitOffset = FuncWordOffset * 32;
2072   DeferredFunctionInfo[F] = FuncBitOffset + FuncBitcodeOffsetDelta;
2073   // Set the LastFunctionBlockBit to point to the last function block.
2074   // Later when parsing is resumed after function materialization,
2075   // we can simply skip that last function block.
2076   if (FuncBitOffset > LastFunctionBlockBit)
2077     LastFunctionBlockBit = FuncBitOffset;
2078 }
2079 
2080 /// Read a new-style GlobalValue symbol table.
2081 Error BitcodeReader::parseGlobalValueSymbolTable() {
2082   unsigned FuncBitcodeOffsetDelta =
2083       Stream.getAbbrevIDWidth() + bitc::BlockIDWidth;
2084 
2085   if (Error Err = Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
2086     return Err;
2087 
2088   SmallVector<uint64_t, 64> Record;
2089   while (true) {
2090     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
2091     if (!MaybeEntry)
2092       return MaybeEntry.takeError();
2093     BitstreamEntry Entry = MaybeEntry.get();
2094 
2095     switch (Entry.Kind) {
2096     case BitstreamEntry::SubBlock:
2097     case BitstreamEntry::Error:
2098       return error("Malformed block");
2099     case BitstreamEntry::EndBlock:
2100       return Error::success();
2101     case BitstreamEntry::Record:
2102       break;
2103     }
2104 
2105     Record.clear();
2106     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
2107     if (!MaybeRecord)
2108       return MaybeRecord.takeError();
2109     switch (MaybeRecord.get()) {
2110     case bitc::VST_CODE_FNENTRY: // [valueid, offset]
2111       setDeferredFunctionInfo(FuncBitcodeOffsetDelta,
2112                               cast<Function>(ValueList[Record[0]]), Record);
2113       break;
2114     }
2115   }
2116 }
2117 
2118 /// Parse the value symbol table at either the current parsing location or
2119 /// at the given bit offset if provided.
2120 Error BitcodeReader::parseValueSymbolTable(uint64_t Offset) {
2121   uint64_t CurrentBit;
2122   // Pass in the Offset to distinguish between calling for the module-level
2123   // VST (where we want to jump to the VST offset) and the function-level
2124   // VST (where we don't).
2125   if (Offset > 0) {
2126     Expected<uint64_t> MaybeCurrentBit = jumpToValueSymbolTable(Offset, Stream);
2127     if (!MaybeCurrentBit)
2128       return MaybeCurrentBit.takeError();
2129     CurrentBit = MaybeCurrentBit.get();
2130     // If this module uses a string table, read this as a module-level VST.
2131     if (UseStrtab) {
2132       if (Error Err = parseGlobalValueSymbolTable())
2133         return Err;
2134       if (Error JumpFailed = Stream.JumpToBit(CurrentBit))
2135         return JumpFailed;
2136       return Error::success();
2137     }
2138     // Otherwise, the VST will be in a similar format to a function-level VST,
2139     // and will contain symbol names.
2140   }
2141 
2142   // Compute the delta between the bitcode indices in the VST (the word offset
2143   // to the word-aligned ENTER_SUBBLOCK for the function block, and that
2144   // expected by the lazy reader. The reader's EnterSubBlock expects to have
2145   // already read the ENTER_SUBBLOCK code (size getAbbrevIDWidth) and BlockID
2146   // (size BlockIDWidth). Note that we access the stream's AbbrevID width here
2147   // just before entering the VST subblock because: 1) the EnterSubBlock
2148   // changes the AbbrevID width; 2) the VST block is nested within the same
2149   // outer MODULE_BLOCK as the FUNCTION_BLOCKs and therefore have the same
2150   // AbbrevID width before calling EnterSubBlock; and 3) when we want to
2151   // jump to the FUNCTION_BLOCK using this offset later, we don't want
2152   // to rely on the stream's AbbrevID width being that of the MODULE_BLOCK.
2153   unsigned FuncBitcodeOffsetDelta =
2154       Stream.getAbbrevIDWidth() + bitc::BlockIDWidth;
2155 
2156   if (Error Err = Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
2157     return Err;
2158 
2159   SmallVector<uint64_t, 64> Record;
2160 
2161   Triple TT(TheModule->getTargetTriple());
2162 
2163   // Read all the records for this value table.
2164   SmallString<128> ValueName;
2165 
2166   while (true) {
2167     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
2168     if (!MaybeEntry)
2169       return MaybeEntry.takeError();
2170     BitstreamEntry Entry = MaybeEntry.get();
2171 
2172     switch (Entry.Kind) {
2173     case BitstreamEntry::SubBlock: // Handled for us already.
2174     case BitstreamEntry::Error:
2175       return error("Malformed block");
2176     case BitstreamEntry::EndBlock:
2177       if (Offset > 0)
2178         if (Error JumpFailed = Stream.JumpToBit(CurrentBit))
2179           return JumpFailed;
2180       return Error::success();
2181     case BitstreamEntry::Record:
2182       // The interesting case.
2183       break;
2184     }
2185 
2186     // Read a record.
2187     Record.clear();
2188     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
2189     if (!MaybeRecord)
2190       return MaybeRecord.takeError();
2191     switch (MaybeRecord.get()) {
2192     default:  // Default behavior: unknown type.
2193       break;
2194     case bitc::VST_CODE_ENTRY: {  // VST_CODE_ENTRY: [valueid, namechar x N]
2195       Expected<Value *> ValOrErr = recordValue(Record, 1, TT);
2196       if (Error Err = ValOrErr.takeError())
2197         return Err;
2198       ValOrErr.get();
2199       break;
2200     }
2201     case bitc::VST_CODE_FNENTRY: {
2202       // VST_CODE_FNENTRY: [valueid, offset, namechar x N]
2203       Expected<Value *> ValOrErr = recordValue(Record, 2, TT);
2204       if (Error Err = ValOrErr.takeError())
2205         return Err;
2206       Value *V = ValOrErr.get();
2207 
2208       // Ignore function offsets emitted for aliases of functions in older
2209       // versions of LLVM.
2210       if (auto *F = dyn_cast<Function>(V))
2211         setDeferredFunctionInfo(FuncBitcodeOffsetDelta, F, Record);
2212       break;
2213     }
2214     case bitc::VST_CODE_BBENTRY: {
2215       if (convertToString(Record, 1, ValueName))
2216         return error("Invalid record");
2217       BasicBlock *BB = getBasicBlock(Record[0]);
2218       if (!BB)
2219         return error("Invalid record");
2220 
2221       BB->setName(StringRef(ValueName.data(), ValueName.size()));
2222       ValueName.clear();
2223       break;
2224     }
2225     }
2226   }
2227 }
2228 
2229 /// Decode a signed value stored with the sign bit in the LSB for dense VBR
2230 /// encoding.
2231 uint64_t BitcodeReader::decodeSignRotatedValue(uint64_t V) {
2232   if ((V & 1) == 0)
2233     return V >> 1;
2234   if (V != 1)
2235     return -(V >> 1);
2236   // There is no such thing as -0 with integers.  "-0" really means MININT.
2237   return 1ULL << 63;
2238 }
2239 
2240 /// Resolve all of the initializers for global values and aliases that we can.
2241 Error BitcodeReader::resolveGlobalAndIndirectSymbolInits() {
2242   std::vector<std::pair<GlobalVariable *, unsigned>> GlobalInitWorklist;
2243   std::vector<std::pair<GlobalIndirectSymbol *, unsigned>>
2244       IndirectSymbolInitWorklist;
2245   std::vector<std::pair<Function *, unsigned>> FunctionPrefixWorklist;
2246   std::vector<std::pair<Function *, unsigned>> FunctionPrologueWorklist;
2247   std::vector<std::pair<Function *, unsigned>> FunctionPersonalityFnWorklist;
2248 
2249   GlobalInitWorklist.swap(GlobalInits);
2250   IndirectSymbolInitWorklist.swap(IndirectSymbolInits);
2251   FunctionPrefixWorklist.swap(FunctionPrefixes);
2252   FunctionPrologueWorklist.swap(FunctionPrologues);
2253   FunctionPersonalityFnWorklist.swap(FunctionPersonalityFns);
2254 
2255   while (!GlobalInitWorklist.empty()) {
2256     unsigned ValID = GlobalInitWorklist.back().second;
2257     if (ValID >= ValueList.size()) {
2258       // Not ready to resolve this yet, it requires something later in the file.
2259       GlobalInits.push_back(GlobalInitWorklist.back());
2260     } else {
2261       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
2262         GlobalInitWorklist.back().first->setInitializer(C);
2263       else
2264         return error("Expected a constant");
2265     }
2266     GlobalInitWorklist.pop_back();
2267   }
2268 
2269   while (!IndirectSymbolInitWorklist.empty()) {
2270     unsigned ValID = IndirectSymbolInitWorklist.back().second;
2271     if (ValID >= ValueList.size()) {
2272       IndirectSymbolInits.push_back(IndirectSymbolInitWorklist.back());
2273     } else {
2274       Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]);
2275       if (!C)
2276         return error("Expected a constant");
2277       GlobalIndirectSymbol *GIS = IndirectSymbolInitWorklist.back().first;
2278       if (isa<GlobalAlias>(GIS) && C->getType() != GIS->getType())
2279         return error("Alias and aliasee types don't match");
2280       GIS->setIndirectSymbol(C);
2281     }
2282     IndirectSymbolInitWorklist.pop_back();
2283   }
2284 
2285   while (!FunctionPrefixWorklist.empty()) {
2286     unsigned ValID = FunctionPrefixWorklist.back().second;
2287     if (ValID >= ValueList.size()) {
2288       FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
2289     } else {
2290       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
2291         FunctionPrefixWorklist.back().first->setPrefixData(C);
2292       else
2293         return error("Expected a constant");
2294     }
2295     FunctionPrefixWorklist.pop_back();
2296   }
2297 
2298   while (!FunctionPrologueWorklist.empty()) {
2299     unsigned ValID = FunctionPrologueWorklist.back().second;
2300     if (ValID >= ValueList.size()) {
2301       FunctionPrologues.push_back(FunctionPrologueWorklist.back());
2302     } else {
2303       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
2304         FunctionPrologueWorklist.back().first->setPrologueData(C);
2305       else
2306         return error("Expected a constant");
2307     }
2308     FunctionPrologueWorklist.pop_back();
2309   }
2310 
2311   while (!FunctionPersonalityFnWorklist.empty()) {
2312     unsigned ValID = FunctionPersonalityFnWorklist.back().second;
2313     if (ValID >= ValueList.size()) {
2314       FunctionPersonalityFns.push_back(FunctionPersonalityFnWorklist.back());
2315     } else {
2316       if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
2317         FunctionPersonalityFnWorklist.back().first->setPersonalityFn(C);
2318       else
2319         return error("Expected a constant");
2320     }
2321     FunctionPersonalityFnWorklist.pop_back();
2322   }
2323 
2324   return Error::success();
2325 }
2326 
2327 APInt llvm::readWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
2328   SmallVector<uint64_t, 8> Words(Vals.size());
2329   transform(Vals, Words.begin(),
2330                  BitcodeReader::decodeSignRotatedValue);
2331 
2332   return APInt(TypeBits, Words);
2333 }
2334 
2335 Error BitcodeReader::parseConstants() {
2336   if (Error Err = Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
2337     return Err;
2338 
2339   SmallVector<uint64_t, 64> Record;
2340 
2341   // Read all the records for this value table.
2342   Type *CurTy = Type::getInt32Ty(Context);
2343   unsigned NextCstNo = ValueList.size();
2344 
2345   struct DelayedShufTy {
2346     VectorType *OpTy;
2347     VectorType *RTy;
2348     uint64_t Op0Idx;
2349     uint64_t Op1Idx;
2350     uint64_t Op2Idx;
2351     unsigned CstNo;
2352   };
2353   std::vector<DelayedShufTy> DelayedShuffles;
2354   while (true) {
2355     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
2356     if (!MaybeEntry)
2357       return MaybeEntry.takeError();
2358     BitstreamEntry Entry = MaybeEntry.get();
2359 
2360     switch (Entry.Kind) {
2361     case BitstreamEntry::SubBlock: // Handled for us already.
2362     case BitstreamEntry::Error:
2363       return error("Malformed block");
2364     case BitstreamEntry::EndBlock:
2365       // Once all the constants have been read, go through and resolve forward
2366       // references.
2367       //
2368       // We have to treat shuffles specially because they don't have three
2369       // operands anymore.  We need to convert the shuffle mask into an array,
2370       // and we can't convert a forward reference.
2371       for (auto &DelayedShuffle : DelayedShuffles) {
2372         VectorType *OpTy = DelayedShuffle.OpTy;
2373         VectorType *RTy = DelayedShuffle.RTy;
2374         uint64_t Op0Idx = DelayedShuffle.Op0Idx;
2375         uint64_t Op1Idx = DelayedShuffle.Op1Idx;
2376         uint64_t Op2Idx = DelayedShuffle.Op2Idx;
2377         uint64_t CstNo = DelayedShuffle.CstNo;
2378         Constant *Op0 = ValueList.getConstantFwdRef(Op0Idx, OpTy);
2379         Constant *Op1 = ValueList.getConstantFwdRef(Op1Idx, OpTy);
2380         Type *ShufTy =
2381             VectorType::get(Type::getInt32Ty(Context), RTy->getElementCount());
2382         Constant *Op2 = ValueList.getConstantFwdRef(Op2Idx, ShufTy);
2383         if (!ShuffleVectorInst::isValidOperands(Op0, Op1, Op2))
2384           return error("Invalid shufflevector operands");
2385         SmallVector<int, 16> Mask;
2386         ShuffleVectorInst::getShuffleMask(Op2, Mask);
2387         Value *V = ConstantExpr::getShuffleVector(Op0, Op1, Mask);
2388         ValueList.assignValue(V, CstNo);
2389       }
2390 
2391       if (NextCstNo != ValueList.size())
2392         return error("Invalid constant reference");
2393 
2394       ValueList.resolveConstantForwardRefs();
2395       return Error::success();
2396     case BitstreamEntry::Record:
2397       // The interesting case.
2398       break;
2399     }
2400 
2401     // Read a record.
2402     Record.clear();
2403     Type *VoidType = Type::getVoidTy(Context);
2404     Value *V = nullptr;
2405     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
2406     if (!MaybeBitCode)
2407       return MaybeBitCode.takeError();
2408     switch (unsigned BitCode = MaybeBitCode.get()) {
2409     default:  // Default behavior: unknown constant
2410     case bitc::CST_CODE_UNDEF:     // UNDEF
2411       V = UndefValue::get(CurTy);
2412       break;
2413     case bitc::CST_CODE_POISON:    // POISON
2414       V = PoisonValue::get(CurTy);
2415       break;
2416     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
2417       if (Record.empty())
2418         return error("Invalid record");
2419       if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
2420         return error("Invalid record");
2421       if (TypeList[Record[0]] == VoidType)
2422         return error("Invalid constant type");
2423       CurTy = TypeList[Record[0]];
2424       continue;  // Skip the ValueList manipulation.
2425     case bitc::CST_CODE_NULL:      // NULL
2426       if (CurTy->isVoidTy() || CurTy->isFunctionTy() || CurTy->isLabelTy())
2427         return error("Invalid type for a constant null value");
2428       V = Constant::getNullValue(CurTy);
2429       break;
2430     case bitc::CST_CODE_INTEGER:   // INTEGER: [intval]
2431       if (!CurTy->isIntegerTy() || Record.empty())
2432         return error("Invalid record");
2433       V = ConstantInt::get(CurTy, decodeSignRotatedValue(Record[0]));
2434       break;
2435     case bitc::CST_CODE_WIDE_INTEGER: {// WIDE_INTEGER: [n x intval]
2436       if (!CurTy->isIntegerTy() || Record.empty())
2437         return error("Invalid record");
2438 
2439       APInt VInt =
2440           readWideAPInt(Record, cast<IntegerType>(CurTy)->getBitWidth());
2441       V = ConstantInt::get(Context, VInt);
2442 
2443       break;
2444     }
2445     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
2446       if (Record.empty())
2447         return error("Invalid record");
2448       if (CurTy->isHalfTy())
2449         V = ConstantFP::get(Context, APFloat(APFloat::IEEEhalf(),
2450                                              APInt(16, (uint16_t)Record[0])));
2451       else if (CurTy->isBFloatTy())
2452         V = ConstantFP::get(Context, APFloat(APFloat::BFloat(),
2453                                              APInt(16, (uint32_t)Record[0])));
2454       else if (CurTy->isFloatTy())
2455         V = ConstantFP::get(Context, APFloat(APFloat::IEEEsingle(),
2456                                              APInt(32, (uint32_t)Record[0])));
2457       else if (CurTy->isDoubleTy())
2458         V = ConstantFP::get(Context, APFloat(APFloat::IEEEdouble(),
2459                                              APInt(64, Record[0])));
2460       else if (CurTy->isX86_FP80Ty()) {
2461         // Bits are not stored the same way as a normal i80 APInt, compensate.
2462         uint64_t Rearrange[2];
2463         Rearrange[0] = (Record[1] & 0xffffLL) | (Record[0] << 16);
2464         Rearrange[1] = Record[0] >> 48;
2465         V = ConstantFP::get(Context, APFloat(APFloat::x87DoubleExtended(),
2466                                              APInt(80, Rearrange)));
2467       } else if (CurTy->isFP128Ty())
2468         V = ConstantFP::get(Context, APFloat(APFloat::IEEEquad(),
2469                                              APInt(128, Record)));
2470       else if (CurTy->isPPC_FP128Ty())
2471         V = ConstantFP::get(Context, APFloat(APFloat::PPCDoubleDouble(),
2472                                              APInt(128, Record)));
2473       else
2474         V = UndefValue::get(CurTy);
2475       break;
2476     }
2477 
2478     case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n x value number]
2479       if (Record.empty())
2480         return error("Invalid record");
2481 
2482       unsigned Size = Record.size();
2483       SmallVector<Constant*, 16> Elts;
2484 
2485       if (StructType *STy = dyn_cast<StructType>(CurTy)) {
2486         for (unsigned i = 0; i != Size; ++i)
2487           Elts.push_back(ValueList.getConstantFwdRef(Record[i],
2488                                                      STy->getElementType(i)));
2489         V = ConstantStruct::get(STy, Elts);
2490       } else if (ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
2491         Type *EltTy = ATy->getElementType();
2492         for (unsigned i = 0; i != Size; ++i)
2493           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
2494         V = ConstantArray::get(ATy, Elts);
2495       } else if (VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
2496         Type *EltTy = VTy->getElementType();
2497         for (unsigned i = 0; i != Size; ++i)
2498           Elts.push_back(ValueList.getConstantFwdRef(Record[i], EltTy));
2499         V = ConstantVector::get(Elts);
2500       } else {
2501         V = UndefValue::get(CurTy);
2502       }
2503       break;
2504     }
2505     case bitc::CST_CODE_STRING:    // STRING: [values]
2506     case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
2507       if (Record.empty())
2508         return error("Invalid record");
2509 
2510       SmallString<16> Elts(Record.begin(), Record.end());
2511       V = ConstantDataArray::getString(Context, Elts,
2512                                        BitCode == bitc::CST_CODE_CSTRING);
2513       break;
2514     }
2515     case bitc::CST_CODE_DATA: {// DATA: [n x value]
2516       if (Record.empty())
2517         return error("Invalid record");
2518 
2519       Type *EltTy;
2520       if (auto *Array = dyn_cast<ArrayType>(CurTy))
2521         EltTy = Array->getElementType();
2522       else
2523         EltTy = cast<VectorType>(CurTy)->getElementType();
2524       if (EltTy->isIntegerTy(8)) {
2525         SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
2526         if (isa<VectorType>(CurTy))
2527           V = ConstantDataVector::get(Context, Elts);
2528         else
2529           V = ConstantDataArray::get(Context, Elts);
2530       } else if (EltTy->isIntegerTy(16)) {
2531         SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
2532         if (isa<VectorType>(CurTy))
2533           V = ConstantDataVector::get(Context, Elts);
2534         else
2535           V = ConstantDataArray::get(Context, Elts);
2536       } else if (EltTy->isIntegerTy(32)) {
2537         SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
2538         if (isa<VectorType>(CurTy))
2539           V = ConstantDataVector::get(Context, Elts);
2540         else
2541           V = ConstantDataArray::get(Context, Elts);
2542       } else if (EltTy->isIntegerTy(64)) {
2543         SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
2544         if (isa<VectorType>(CurTy))
2545           V = ConstantDataVector::get(Context, Elts);
2546         else
2547           V = ConstantDataArray::get(Context, Elts);
2548       } else if (EltTy->isHalfTy()) {
2549         SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
2550         if (isa<VectorType>(CurTy))
2551           V = ConstantDataVector::getFP(EltTy, Elts);
2552         else
2553           V = ConstantDataArray::getFP(EltTy, Elts);
2554       } else if (EltTy->isBFloatTy()) {
2555         SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
2556         if (isa<VectorType>(CurTy))
2557           V = ConstantDataVector::getFP(EltTy, Elts);
2558         else
2559           V = ConstantDataArray::getFP(EltTy, Elts);
2560       } else if (EltTy->isFloatTy()) {
2561         SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
2562         if (isa<VectorType>(CurTy))
2563           V = ConstantDataVector::getFP(EltTy, Elts);
2564         else
2565           V = ConstantDataArray::getFP(EltTy, Elts);
2566       } else if (EltTy->isDoubleTy()) {
2567         SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
2568         if (isa<VectorType>(CurTy))
2569           V = ConstantDataVector::getFP(EltTy, Elts);
2570         else
2571           V = ConstantDataArray::getFP(EltTy, Elts);
2572       } else {
2573         return error("Invalid type for value");
2574       }
2575       break;
2576     }
2577     case bitc::CST_CODE_CE_UNOP: {  // CE_UNOP: [opcode, opval]
2578       if (Record.size() < 2)
2579         return error("Invalid record");
2580       int Opc = getDecodedUnaryOpcode(Record[0], CurTy);
2581       if (Opc < 0) {
2582         V = UndefValue::get(CurTy);  // Unknown unop.
2583       } else {
2584         Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
2585         unsigned Flags = 0;
2586         V = ConstantExpr::get(Opc, LHS, Flags);
2587       }
2588       break;
2589     }
2590     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
2591       if (Record.size() < 3)
2592         return error("Invalid record");
2593       int Opc = getDecodedBinaryOpcode(Record[0], CurTy);
2594       if (Opc < 0) {
2595         V = UndefValue::get(CurTy);  // Unknown binop.
2596       } else {
2597         Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
2598         Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
2599         unsigned Flags = 0;
2600         if (Record.size() >= 4) {
2601           if (Opc == Instruction::Add ||
2602               Opc == Instruction::Sub ||
2603               Opc == Instruction::Mul ||
2604               Opc == Instruction::Shl) {
2605             if (Record[3] & (1 << bitc::OBO_NO_SIGNED_WRAP))
2606               Flags |= OverflowingBinaryOperator::NoSignedWrap;
2607             if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
2608               Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
2609           } else if (Opc == Instruction::SDiv ||
2610                      Opc == Instruction::UDiv ||
2611                      Opc == Instruction::LShr ||
2612                      Opc == Instruction::AShr) {
2613             if (Record[3] & (1 << bitc::PEO_EXACT))
2614               Flags |= SDivOperator::IsExact;
2615           }
2616         }
2617         V = ConstantExpr::get(Opc, LHS, RHS, Flags);
2618       }
2619       break;
2620     }
2621     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
2622       if (Record.size() < 3)
2623         return error("Invalid record");
2624       int Opc = getDecodedCastOpcode(Record[0]);
2625       if (Opc < 0) {
2626         V = UndefValue::get(CurTy);  // Unknown cast.
2627       } else {
2628         Type *OpTy = getTypeByID(Record[1]);
2629         if (!OpTy)
2630           return error("Invalid record");
2631         Constant *Op = ValueList.getConstantFwdRef(Record[2], OpTy);
2632         V = UpgradeBitCastExpr(Opc, Op, CurTy);
2633         if (!V) V = ConstantExpr::getCast(Opc, Op, CurTy);
2634       }
2635       break;
2636     }
2637     case bitc::CST_CODE_CE_INBOUNDS_GEP: // [ty, n x operands]
2638     case bitc::CST_CODE_CE_GEP: // [ty, n x operands]
2639     case bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX: { // [ty, flags, n x
2640                                                      // operands]
2641       unsigned OpNum = 0;
2642       Type *PointeeType = nullptr;
2643       if (BitCode == bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX ||
2644           Record.size() % 2)
2645         PointeeType = getTypeByID(Record[OpNum++]);
2646 
2647       bool InBounds = false;
2648       Optional<unsigned> InRangeIndex;
2649       if (BitCode == bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX) {
2650         uint64_t Op = Record[OpNum++];
2651         InBounds = Op & 1;
2652         InRangeIndex = Op >> 1;
2653       } else if (BitCode == bitc::CST_CODE_CE_INBOUNDS_GEP)
2654         InBounds = true;
2655 
2656       SmallVector<Constant*, 16> Elts;
2657       Type *Elt0FullTy = nullptr;
2658       while (OpNum != Record.size()) {
2659         if (!Elt0FullTy)
2660           Elt0FullTy = getTypeByID(Record[OpNum]);
2661         Type *ElTy = getTypeByID(Record[OpNum++]);
2662         if (!ElTy)
2663           return error("Invalid record");
2664         Elts.push_back(ValueList.getConstantFwdRef(Record[OpNum++], ElTy));
2665       }
2666 
2667       if (Elts.size() < 1)
2668         return error("Invalid gep with no operands");
2669 
2670       PointerType *OrigPtrTy = cast<PointerType>(Elt0FullTy->getScalarType());
2671       if (!PointeeType)
2672         PointeeType = OrigPtrTy->getElementType();
2673       else if (!OrigPtrTy->isOpaqueOrPointeeTypeMatches(PointeeType))
2674         return error("Explicit gep operator type does not match pointee type "
2675                      "of pointer operand");
2676 
2677       ArrayRef<Constant *> Indices(Elts.begin() + 1, Elts.end());
2678       V = ConstantExpr::getGetElementPtr(PointeeType, Elts[0], Indices,
2679                                          InBounds, InRangeIndex);
2680       break;
2681     }
2682     case bitc::CST_CODE_CE_SELECT: {  // CE_SELECT: [opval#, opval#, opval#]
2683       if (Record.size() < 3)
2684         return error("Invalid record");
2685 
2686       Type *SelectorTy = Type::getInt1Ty(Context);
2687 
2688       // The selector might be an i1, an <n x i1>, or a <vscale x n x i1>
2689       // Get the type from the ValueList before getting a forward ref.
2690       if (VectorType *VTy = dyn_cast<VectorType>(CurTy))
2691         if (Value *V = ValueList[Record[0]])
2692           if (SelectorTy != V->getType())
2693             SelectorTy = VectorType::get(SelectorTy,
2694                                          VTy->getElementCount());
2695 
2696       V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
2697                                                               SelectorTy),
2698                                   ValueList.getConstantFwdRef(Record[1],CurTy),
2699                                   ValueList.getConstantFwdRef(Record[2],CurTy));
2700       break;
2701     }
2702     case bitc::CST_CODE_CE_EXTRACTELT
2703         : { // CE_EXTRACTELT: [opty, opval, opty, opval]
2704       if (Record.size() < 3)
2705         return error("Invalid record");
2706       VectorType *OpTy =
2707         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
2708       if (!OpTy)
2709         return error("Invalid record");
2710       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2711       Constant *Op1 = nullptr;
2712       if (Record.size() == 4) {
2713         Type *IdxTy = getTypeByID(Record[2]);
2714         if (!IdxTy)
2715           return error("Invalid record");
2716         Op1 = ValueList.getConstantFwdRef(Record[3], IdxTy);
2717       } else {
2718         // Deprecated, but still needed to read old bitcode files.
2719         Op1 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
2720       }
2721       if (!Op1)
2722         return error("Invalid record");
2723       V = ConstantExpr::getExtractElement(Op0, Op1);
2724       break;
2725     }
2726     case bitc::CST_CODE_CE_INSERTELT
2727         : { // CE_INSERTELT: [opval, opval, opty, opval]
2728       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2729       if (Record.size() < 3 || !OpTy)
2730         return error("Invalid record");
2731       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
2732       Constant *Op1 = ValueList.getConstantFwdRef(Record[1],
2733                                                   OpTy->getElementType());
2734       Constant *Op2 = nullptr;
2735       if (Record.size() == 4) {
2736         Type *IdxTy = getTypeByID(Record[2]);
2737         if (!IdxTy)
2738           return error("Invalid record");
2739         Op2 = ValueList.getConstantFwdRef(Record[3], IdxTy);
2740       } else {
2741         // Deprecated, but still needed to read old bitcode files.
2742         Op2 = ValueList.getConstantFwdRef(Record[2], Type::getInt32Ty(Context));
2743       }
2744       if (!Op2)
2745         return error("Invalid record");
2746       V = ConstantExpr::getInsertElement(Op0, Op1, Op2);
2747       break;
2748     }
2749     case bitc::CST_CODE_CE_SHUFFLEVEC: { // CE_SHUFFLEVEC: [opval, opval, opval]
2750       VectorType *OpTy = dyn_cast<VectorType>(CurTy);
2751       if (Record.size() < 3 || !OpTy)
2752         return error("Invalid record");
2753       DelayedShuffles.push_back(
2754           {OpTy, OpTy, Record[0], Record[1], Record[2], NextCstNo});
2755       ++NextCstNo;
2756       continue;
2757     }
2758     case bitc::CST_CODE_CE_SHUFVEC_EX: { // [opty, opval, opval, opval]
2759       VectorType *RTy = dyn_cast<VectorType>(CurTy);
2760       VectorType *OpTy =
2761         dyn_cast_or_null<VectorType>(getTypeByID(Record[0]));
2762       if (Record.size() < 4 || !RTy || !OpTy)
2763         return error("Invalid record");
2764       DelayedShuffles.push_back(
2765           {OpTy, RTy, Record[1], Record[2], Record[3], NextCstNo});
2766       ++NextCstNo;
2767       continue;
2768     }
2769     case bitc::CST_CODE_CE_CMP: {     // CE_CMP: [opty, opval, opval, pred]
2770       if (Record.size() < 4)
2771         return error("Invalid record");
2772       Type *OpTy = getTypeByID(Record[0]);
2773       if (!OpTy)
2774         return error("Invalid record");
2775       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
2776       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
2777 
2778       if (OpTy->isFPOrFPVectorTy())
2779         V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
2780       else
2781         V = ConstantExpr::getICmp(Record[3], Op0, Op1);
2782       break;
2783     }
2784     // This maintains backward compatibility, pre-asm dialect keywords.
2785     // Deprecated, but still needed to read old bitcode files.
2786     case bitc::CST_CODE_INLINEASM_OLD: {
2787       if (Record.size() < 2)
2788         return error("Invalid record");
2789       std::string AsmStr, ConstrStr;
2790       bool HasSideEffects = Record[0] & 1;
2791       bool IsAlignStack = Record[0] >> 1;
2792       unsigned AsmStrSize = Record[1];
2793       if (2+AsmStrSize >= Record.size())
2794         return error("Invalid record");
2795       unsigned ConstStrSize = Record[2+AsmStrSize];
2796       if (3+AsmStrSize+ConstStrSize > Record.size())
2797         return error("Invalid record");
2798 
2799       for (unsigned i = 0; i != AsmStrSize; ++i)
2800         AsmStr += (char)Record[2+i];
2801       for (unsigned i = 0; i != ConstStrSize; ++i)
2802         ConstrStr += (char)Record[3+AsmStrSize+i];
2803       UpgradeInlineAsmString(&AsmStr);
2804       V = InlineAsm::get(
2805           cast<FunctionType>(cast<PointerType>(CurTy)->getElementType()),
2806           AsmStr, ConstrStr, HasSideEffects, IsAlignStack);
2807       break;
2808     }
2809     // This version adds support for the asm dialect keywords (e.g.,
2810     // inteldialect).
2811     case bitc::CST_CODE_INLINEASM_OLD2: {
2812       if (Record.size() < 2)
2813         return error("Invalid record");
2814       std::string AsmStr, ConstrStr;
2815       bool HasSideEffects = Record[0] & 1;
2816       bool IsAlignStack = (Record[0] >> 1) & 1;
2817       unsigned AsmDialect = Record[0] >> 2;
2818       unsigned AsmStrSize = Record[1];
2819       if (2+AsmStrSize >= Record.size())
2820         return error("Invalid record");
2821       unsigned ConstStrSize = Record[2+AsmStrSize];
2822       if (3+AsmStrSize+ConstStrSize > Record.size())
2823         return error("Invalid record");
2824 
2825       for (unsigned i = 0; i != AsmStrSize; ++i)
2826         AsmStr += (char)Record[2+i];
2827       for (unsigned i = 0; i != ConstStrSize; ++i)
2828         ConstrStr += (char)Record[3+AsmStrSize+i];
2829       UpgradeInlineAsmString(&AsmStr);
2830       V = InlineAsm::get(
2831           cast<FunctionType>(cast<PointerType>(CurTy)->getElementType()),
2832           AsmStr, ConstrStr, HasSideEffects, IsAlignStack,
2833           InlineAsm::AsmDialect(AsmDialect));
2834       break;
2835     }
2836     // This version adds support for the unwind keyword.
2837     case bitc::CST_CODE_INLINEASM: {
2838       if (Record.size() < 2)
2839         return error("Invalid record");
2840       std::string AsmStr, ConstrStr;
2841       bool HasSideEffects = Record[0] & 1;
2842       bool IsAlignStack = (Record[0] >> 1) & 1;
2843       unsigned AsmDialect = (Record[0] >> 2) & 1;
2844       bool CanThrow = (Record[0] >> 3) & 1;
2845       unsigned AsmStrSize = Record[1];
2846       if (2 + AsmStrSize >= Record.size())
2847         return error("Invalid record");
2848       unsigned ConstStrSize = Record[2 + AsmStrSize];
2849       if (3 + AsmStrSize + ConstStrSize > Record.size())
2850         return error("Invalid record");
2851 
2852       for (unsigned i = 0; i != AsmStrSize; ++i)
2853         AsmStr += (char)Record[2 + i];
2854       for (unsigned i = 0; i != ConstStrSize; ++i)
2855         ConstrStr += (char)Record[3 + AsmStrSize + i];
2856       UpgradeInlineAsmString(&AsmStr);
2857       V = InlineAsm::get(
2858           cast<FunctionType>(cast<PointerType>(CurTy)->getElementType()),
2859           AsmStr, ConstrStr, HasSideEffects, IsAlignStack,
2860           InlineAsm::AsmDialect(AsmDialect), CanThrow);
2861       break;
2862     }
2863     case bitc::CST_CODE_BLOCKADDRESS:{
2864       if (Record.size() < 3)
2865         return error("Invalid record");
2866       Type *FnTy = getTypeByID(Record[0]);
2867       if (!FnTy)
2868         return error("Invalid record");
2869       Function *Fn =
2870         dyn_cast_or_null<Function>(ValueList.getConstantFwdRef(Record[1],FnTy));
2871       if (!Fn)
2872         return error("Invalid record");
2873 
2874       // If the function is already parsed we can insert the block address right
2875       // away.
2876       BasicBlock *BB;
2877       unsigned BBID = Record[2];
2878       if (!BBID)
2879         // Invalid reference to entry block.
2880         return error("Invalid ID");
2881       if (!Fn->empty()) {
2882         Function::iterator BBI = Fn->begin(), BBE = Fn->end();
2883         for (size_t I = 0, E = BBID; I != E; ++I) {
2884           if (BBI == BBE)
2885             return error("Invalid ID");
2886           ++BBI;
2887         }
2888         BB = &*BBI;
2889       } else {
2890         // Otherwise insert a placeholder and remember it so it can be inserted
2891         // when the function is parsed.
2892         auto &FwdBBs = BasicBlockFwdRefs[Fn];
2893         if (FwdBBs.empty())
2894           BasicBlockFwdRefQueue.push_back(Fn);
2895         if (FwdBBs.size() < BBID + 1)
2896           FwdBBs.resize(BBID + 1);
2897         if (!FwdBBs[BBID])
2898           FwdBBs[BBID] = BasicBlock::Create(Context);
2899         BB = FwdBBs[BBID];
2900       }
2901       V = BlockAddress::get(Fn, BB);
2902       break;
2903     }
2904     case bitc::CST_CODE_DSO_LOCAL_EQUIVALENT: {
2905       if (Record.size() < 2)
2906         return error("Invalid record");
2907       Type *GVTy = getTypeByID(Record[0]);
2908       if (!GVTy)
2909         return error("Invalid record");
2910       GlobalValue *GV = dyn_cast_or_null<GlobalValue>(
2911           ValueList.getConstantFwdRef(Record[1], GVTy));
2912       if (!GV)
2913         return error("Invalid record");
2914 
2915       V = DSOLocalEquivalent::get(GV);
2916       break;
2917     }
2918     }
2919 
2920     ValueList.assignValue(V, NextCstNo);
2921     ++NextCstNo;
2922   }
2923 }
2924 
2925 Error BitcodeReader::parseUseLists() {
2926   if (Error Err = Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
2927     return Err;
2928 
2929   // Read all the records.
2930   SmallVector<uint64_t, 64> Record;
2931 
2932   while (true) {
2933     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
2934     if (!MaybeEntry)
2935       return MaybeEntry.takeError();
2936     BitstreamEntry Entry = MaybeEntry.get();
2937 
2938     switch (Entry.Kind) {
2939     case BitstreamEntry::SubBlock: // Handled for us already.
2940     case BitstreamEntry::Error:
2941       return error("Malformed block");
2942     case BitstreamEntry::EndBlock:
2943       return Error::success();
2944     case BitstreamEntry::Record:
2945       // The interesting case.
2946       break;
2947     }
2948 
2949     // Read a use list record.
2950     Record.clear();
2951     bool IsBB = false;
2952     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
2953     if (!MaybeRecord)
2954       return MaybeRecord.takeError();
2955     switch (MaybeRecord.get()) {
2956     default:  // Default behavior: unknown type.
2957       break;
2958     case bitc::USELIST_CODE_BB:
2959       IsBB = true;
2960       LLVM_FALLTHROUGH;
2961     case bitc::USELIST_CODE_DEFAULT: {
2962       unsigned RecordLength = Record.size();
2963       if (RecordLength < 3)
2964         // Records should have at least an ID and two indexes.
2965         return error("Invalid record");
2966       unsigned ID = Record.pop_back_val();
2967 
2968       Value *V;
2969       if (IsBB) {
2970         assert(ID < FunctionBBs.size() && "Basic block not found");
2971         V = FunctionBBs[ID];
2972       } else
2973         V = ValueList[ID];
2974       unsigned NumUses = 0;
2975       SmallDenseMap<const Use *, unsigned, 16> Order;
2976       for (const Use &U : V->materialized_uses()) {
2977         if (++NumUses > Record.size())
2978           break;
2979         Order[&U] = Record[NumUses - 1];
2980       }
2981       if (Order.size() != Record.size() || NumUses > Record.size())
2982         // Mismatches can happen if the functions are being materialized lazily
2983         // (out-of-order), or a value has been upgraded.
2984         break;
2985 
2986       V->sortUseList([&](const Use &L, const Use &R) {
2987         return Order.lookup(&L) < Order.lookup(&R);
2988       });
2989       break;
2990     }
2991     }
2992   }
2993 }
2994 
2995 /// When we see the block for metadata, remember where it is and then skip it.
2996 /// This lets us lazily deserialize the metadata.
2997 Error BitcodeReader::rememberAndSkipMetadata() {
2998   // Save the current stream state.
2999   uint64_t CurBit = Stream.GetCurrentBitNo();
3000   DeferredMetadataInfo.push_back(CurBit);
3001 
3002   // Skip over the block for now.
3003   if (Error Err = Stream.SkipBlock())
3004     return Err;
3005   return Error::success();
3006 }
3007 
3008 Error BitcodeReader::materializeMetadata() {
3009   for (uint64_t BitPos : DeferredMetadataInfo) {
3010     // Move the bit stream to the saved position.
3011     if (Error JumpFailed = Stream.JumpToBit(BitPos))
3012       return JumpFailed;
3013     if (Error Err = MDLoader->parseModuleMetadata())
3014       return Err;
3015   }
3016 
3017   // Upgrade "Linker Options" module flag to "llvm.linker.options" module-level
3018   // metadata. Only upgrade if the new option doesn't exist to avoid upgrade
3019   // multiple times.
3020   if (!TheModule->getNamedMetadata("llvm.linker.options")) {
3021     if (Metadata *Val = TheModule->getModuleFlag("Linker Options")) {
3022       NamedMDNode *LinkerOpts =
3023           TheModule->getOrInsertNamedMetadata("llvm.linker.options");
3024       for (const MDOperand &MDOptions : cast<MDNode>(Val)->operands())
3025         LinkerOpts->addOperand(cast<MDNode>(MDOptions));
3026     }
3027   }
3028 
3029   DeferredMetadataInfo.clear();
3030   return Error::success();
3031 }
3032 
3033 void BitcodeReader::setStripDebugInfo() { StripDebugInfo = true; }
3034 
3035 /// When we see the block for a function body, remember where it is and then
3036 /// skip it.  This lets us lazily deserialize the functions.
3037 Error BitcodeReader::rememberAndSkipFunctionBody() {
3038   // Get the function we are talking about.
3039   if (FunctionsWithBodies.empty())
3040     return error("Insufficient function protos");
3041 
3042   Function *Fn = FunctionsWithBodies.back();
3043   FunctionsWithBodies.pop_back();
3044 
3045   // Save the current stream state.
3046   uint64_t CurBit = Stream.GetCurrentBitNo();
3047   assert(
3048       (DeferredFunctionInfo[Fn] == 0 || DeferredFunctionInfo[Fn] == CurBit) &&
3049       "Mismatch between VST and scanned function offsets");
3050   DeferredFunctionInfo[Fn] = CurBit;
3051 
3052   // Skip over the function block for now.
3053   if (Error Err = Stream.SkipBlock())
3054     return Err;
3055   return Error::success();
3056 }
3057 
3058 Error BitcodeReader::globalCleanup() {
3059   // Patch the initializers for globals and aliases up.
3060   if (Error Err = resolveGlobalAndIndirectSymbolInits())
3061     return Err;
3062   if (!GlobalInits.empty() || !IndirectSymbolInits.empty())
3063     return error("Malformed global initializer set");
3064 
3065   // Look for intrinsic functions which need to be upgraded at some point
3066   // and functions that need to have their function attributes upgraded.
3067   for (Function &F : *TheModule) {
3068     MDLoader->upgradeDebugIntrinsics(F);
3069     Function *NewFn;
3070     if (UpgradeIntrinsicFunction(&F, NewFn))
3071       UpgradedIntrinsics[&F] = NewFn;
3072     else if (auto Remangled = Intrinsic::remangleIntrinsicFunction(&F))
3073       // Some types could be renamed during loading if several modules are
3074       // loaded in the same LLVMContext (LTO scenario). In this case we should
3075       // remangle intrinsics names as well.
3076       RemangledIntrinsics[&F] = Remangled.getValue();
3077     // Look for functions that rely on old function attribute behavior.
3078     UpgradeFunctionAttributes(F);
3079   }
3080 
3081   // Look for global variables which need to be renamed.
3082   std::vector<std::pair<GlobalVariable *, GlobalVariable *>> UpgradedVariables;
3083   for (GlobalVariable &GV : TheModule->globals())
3084     if (GlobalVariable *Upgraded = UpgradeGlobalVariable(&GV))
3085       UpgradedVariables.emplace_back(&GV, Upgraded);
3086   for (auto &Pair : UpgradedVariables) {
3087     Pair.first->eraseFromParent();
3088     TheModule->getGlobalList().push_back(Pair.second);
3089   }
3090 
3091   // Force deallocation of memory for these vectors to favor the client that
3092   // want lazy deserialization.
3093   std::vector<std::pair<GlobalVariable *, unsigned>>().swap(GlobalInits);
3094   std::vector<std::pair<GlobalIndirectSymbol *, unsigned>>().swap(
3095       IndirectSymbolInits);
3096   return Error::success();
3097 }
3098 
3099 /// Support for lazy parsing of function bodies. This is required if we
3100 /// either have an old bitcode file without a VST forward declaration record,
3101 /// or if we have an anonymous function being materialized, since anonymous
3102 /// functions do not have a name and are therefore not in the VST.
3103 Error BitcodeReader::rememberAndSkipFunctionBodies() {
3104   if (Error JumpFailed = Stream.JumpToBit(NextUnreadBit))
3105     return JumpFailed;
3106 
3107   if (Stream.AtEndOfStream())
3108     return error("Could not find function in stream");
3109 
3110   if (!SeenFirstFunctionBody)
3111     return error("Trying to materialize functions before seeing function blocks");
3112 
3113   // An old bitcode file with the symbol table at the end would have
3114   // finished the parse greedily.
3115   assert(SeenValueSymbolTable);
3116 
3117   SmallVector<uint64_t, 64> Record;
3118 
3119   while (true) {
3120     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
3121     if (!MaybeEntry)
3122       return MaybeEntry.takeError();
3123     llvm::BitstreamEntry Entry = MaybeEntry.get();
3124 
3125     switch (Entry.Kind) {
3126     default:
3127       return error("Expect SubBlock");
3128     case BitstreamEntry::SubBlock:
3129       switch (Entry.ID) {
3130       default:
3131         return error("Expect function block");
3132       case bitc::FUNCTION_BLOCK_ID:
3133         if (Error Err = rememberAndSkipFunctionBody())
3134           return Err;
3135         NextUnreadBit = Stream.GetCurrentBitNo();
3136         return Error::success();
3137       }
3138     }
3139   }
3140 }
3141 
3142 bool BitcodeReaderBase::readBlockInfo() {
3143   Expected<Optional<BitstreamBlockInfo>> MaybeNewBlockInfo =
3144       Stream.ReadBlockInfoBlock();
3145   if (!MaybeNewBlockInfo)
3146     return true; // FIXME Handle the error.
3147   Optional<BitstreamBlockInfo> NewBlockInfo =
3148       std::move(MaybeNewBlockInfo.get());
3149   if (!NewBlockInfo)
3150     return true;
3151   BlockInfo = std::move(*NewBlockInfo);
3152   return false;
3153 }
3154 
3155 Error BitcodeReader::parseComdatRecord(ArrayRef<uint64_t> Record) {
3156   // v1: [selection_kind, name]
3157   // v2: [strtab_offset, strtab_size, selection_kind]
3158   StringRef Name;
3159   std::tie(Name, Record) = readNameFromStrtab(Record);
3160 
3161   if (Record.empty())
3162     return error("Invalid record");
3163   Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
3164   std::string OldFormatName;
3165   if (!UseStrtab) {
3166     if (Record.size() < 2)
3167       return error("Invalid record");
3168     unsigned ComdatNameSize = Record[1];
3169     OldFormatName.reserve(ComdatNameSize);
3170     for (unsigned i = 0; i != ComdatNameSize; ++i)
3171       OldFormatName += (char)Record[2 + i];
3172     Name = OldFormatName;
3173   }
3174   Comdat *C = TheModule->getOrInsertComdat(Name);
3175   C->setSelectionKind(SK);
3176   ComdatList.push_back(C);
3177   return Error::success();
3178 }
3179 
3180 static void inferDSOLocal(GlobalValue *GV) {
3181   // infer dso_local from linkage and visibility if it is not encoded.
3182   if (GV->hasLocalLinkage() ||
3183       (!GV->hasDefaultVisibility() && !GV->hasExternalWeakLinkage()))
3184     GV->setDSOLocal(true);
3185 }
3186 
3187 Error BitcodeReader::parseGlobalVarRecord(ArrayRef<uint64_t> Record) {
3188   // v1: [pointer type, isconst, initid, linkage, alignment, section,
3189   // visibility, threadlocal, unnamed_addr, externally_initialized,
3190   // dllstorageclass, comdat, attributes, preemption specifier,
3191   // partition strtab offset, partition strtab size] (name in VST)
3192   // v2: [strtab_offset, strtab_size, v1]
3193   StringRef Name;
3194   std::tie(Name, Record) = readNameFromStrtab(Record);
3195 
3196   if (Record.size() < 6)
3197     return error("Invalid record");
3198   Type *Ty = getTypeByID(Record[0]);
3199   if (!Ty)
3200     return error("Invalid record");
3201   bool isConstant = Record[1] & 1;
3202   bool explicitType = Record[1] & 2;
3203   unsigned AddressSpace;
3204   if (explicitType) {
3205     AddressSpace = Record[1] >> 2;
3206   } else {
3207     if (!Ty->isPointerTy())
3208       return error("Invalid type for value");
3209     AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
3210     Ty = cast<PointerType>(Ty)->getElementType();
3211   }
3212 
3213   uint64_t RawLinkage = Record[3];
3214   GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
3215   MaybeAlign Alignment;
3216   if (Error Err = parseAlignmentValue(Record[4], Alignment))
3217     return Err;
3218   std::string Section;
3219   if (Record[5]) {
3220     if (Record[5] - 1 >= SectionTable.size())
3221       return error("Invalid ID");
3222     Section = SectionTable[Record[5] - 1];
3223   }
3224   GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
3225   // Local linkage must have default visibility.
3226   // auto-upgrade `hidden` and `protected` for old bitcode.
3227   if (Record.size() > 6 && !GlobalValue::isLocalLinkage(Linkage))
3228     Visibility = getDecodedVisibility(Record[6]);
3229 
3230   GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
3231   if (Record.size() > 7)
3232     TLM = getDecodedThreadLocalMode(Record[7]);
3233 
3234   GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
3235   if (Record.size() > 8)
3236     UnnamedAddr = getDecodedUnnamedAddrType(Record[8]);
3237 
3238   bool ExternallyInitialized = false;
3239   if (Record.size() > 9)
3240     ExternallyInitialized = Record[9];
3241 
3242   GlobalVariable *NewGV =
3243       new GlobalVariable(*TheModule, Ty, isConstant, Linkage, nullptr, Name,
3244                          nullptr, TLM, AddressSpace, ExternallyInitialized);
3245   NewGV->setAlignment(Alignment);
3246   if (!Section.empty())
3247     NewGV->setSection(Section);
3248   NewGV->setVisibility(Visibility);
3249   NewGV->setUnnamedAddr(UnnamedAddr);
3250 
3251   if (Record.size() > 10)
3252     NewGV->setDLLStorageClass(getDecodedDLLStorageClass(Record[10]));
3253   else
3254     upgradeDLLImportExportLinkage(NewGV, RawLinkage);
3255 
3256   ValueList.push_back(NewGV);
3257 
3258   // Remember which value to use for the global initializer.
3259   if (unsigned InitID = Record[2])
3260     GlobalInits.push_back(std::make_pair(NewGV, InitID - 1));
3261 
3262   if (Record.size() > 11) {
3263     if (unsigned ComdatID = Record[11]) {
3264       if (ComdatID > ComdatList.size())
3265         return error("Invalid global variable comdat ID");
3266       NewGV->setComdat(ComdatList[ComdatID - 1]);
3267     }
3268   } else if (hasImplicitComdat(RawLinkage)) {
3269     NewGV->setComdat(reinterpret_cast<Comdat *>(1));
3270   }
3271 
3272   if (Record.size() > 12) {
3273     auto AS = getAttributes(Record[12]).getFnAttributes();
3274     NewGV->setAttributes(AS);
3275   }
3276 
3277   if (Record.size() > 13) {
3278     NewGV->setDSOLocal(getDecodedDSOLocal(Record[13]));
3279   }
3280   inferDSOLocal(NewGV);
3281 
3282   // Check whether we have enough values to read a partition name.
3283   if (Record.size() > 15)
3284     NewGV->setPartition(StringRef(Strtab.data() + Record[14], Record[15]));
3285 
3286   return Error::success();
3287 }
3288 
3289 Error BitcodeReader::parseFunctionRecord(ArrayRef<uint64_t> Record) {
3290   // v1: [type, callingconv, isproto, linkage, paramattr, alignment, section,
3291   // visibility, gc, unnamed_addr, prologuedata, dllstorageclass, comdat,
3292   // prefixdata,  personalityfn, preemption specifier, addrspace] (name in VST)
3293   // v2: [strtab_offset, strtab_size, v1]
3294   StringRef Name;
3295   std::tie(Name, Record) = readNameFromStrtab(Record);
3296 
3297   if (Record.size() < 8)
3298     return error("Invalid record");
3299   Type *FTy = getTypeByID(Record[0]);
3300   if (!FTy)
3301     return error("Invalid record");
3302   if (auto *PTy = dyn_cast<PointerType>(FTy))
3303     FTy = PTy->getElementType();
3304 
3305   if (!isa<FunctionType>(FTy))
3306     return error("Invalid type for value");
3307   auto CC = static_cast<CallingConv::ID>(Record[1]);
3308   if (CC & ~CallingConv::MaxID)
3309     return error("Invalid calling convention ID");
3310 
3311   unsigned AddrSpace = TheModule->getDataLayout().getProgramAddressSpace();
3312   if (Record.size() > 16)
3313     AddrSpace = Record[16];
3314 
3315   Function *Func =
3316       Function::Create(cast<FunctionType>(FTy), GlobalValue::ExternalLinkage,
3317                        AddrSpace, Name, TheModule);
3318 
3319   assert(Func->getFunctionType() == FTy &&
3320          "Incorrect fully specified type provided for function");
3321   FunctionTypes[Func] = cast<FunctionType>(FTy);
3322 
3323   Func->setCallingConv(CC);
3324   bool isProto = Record[2];
3325   uint64_t RawLinkage = Record[3];
3326   Func->setLinkage(getDecodedLinkage(RawLinkage));
3327   Func->setAttributes(getAttributes(Record[4]));
3328 
3329   // Upgrade any old-style byval or sret without a type by propagating the
3330   // argument's pointee type. There should be no opaque pointers where the byval
3331   // type is implicit.
3332   for (unsigned i = 0; i != Func->arg_size(); ++i) {
3333     for (Attribute::AttrKind Kind : {Attribute::ByVal, Attribute::StructRet,
3334                                      Attribute::InAlloca}) {
3335       if (!Func->hasParamAttribute(i, Kind))
3336         continue;
3337 
3338       if (Func->getParamAttribute(i, Kind).getValueAsType())
3339         continue;
3340 
3341       Func->removeParamAttr(i, Kind);
3342 
3343       Type *PTy = cast<FunctionType>(FTy)->getParamType(i);
3344       Type *PtrEltTy = cast<PointerType>(PTy)->getElementType();
3345       Attribute NewAttr;
3346       switch (Kind) {
3347       case Attribute::ByVal:
3348         NewAttr = Attribute::getWithByValType(Context, PtrEltTy);
3349         break;
3350       case Attribute::StructRet:
3351         NewAttr = Attribute::getWithStructRetType(Context, PtrEltTy);
3352         break;
3353       case Attribute::InAlloca:
3354         NewAttr = Attribute::getWithInAllocaType(Context, PtrEltTy);
3355         break;
3356       default:
3357         llvm_unreachable("not an upgraded type attribute");
3358       }
3359 
3360       Func->addParamAttr(i, NewAttr);
3361     }
3362   }
3363 
3364   MaybeAlign Alignment;
3365   if (Error Err = parseAlignmentValue(Record[5], Alignment))
3366     return Err;
3367   Func->setAlignment(Alignment);
3368   if (Record[6]) {
3369     if (Record[6] - 1 >= SectionTable.size())
3370       return error("Invalid ID");
3371     Func->setSection(SectionTable[Record[6] - 1]);
3372   }
3373   // Local linkage must have default visibility.
3374   // auto-upgrade `hidden` and `protected` for old bitcode.
3375   if (!Func->hasLocalLinkage())
3376     Func->setVisibility(getDecodedVisibility(Record[7]));
3377   if (Record.size() > 8 && Record[8]) {
3378     if (Record[8] - 1 >= GCTable.size())
3379       return error("Invalid ID");
3380     Func->setGC(GCTable[Record[8] - 1]);
3381   }
3382   GlobalValue::UnnamedAddr UnnamedAddr = GlobalValue::UnnamedAddr::None;
3383   if (Record.size() > 9)
3384     UnnamedAddr = getDecodedUnnamedAddrType(Record[9]);
3385   Func->setUnnamedAddr(UnnamedAddr);
3386   if (Record.size() > 10 && Record[10] != 0)
3387     FunctionPrologues.push_back(std::make_pair(Func, Record[10] - 1));
3388 
3389   if (Record.size() > 11)
3390     Func->setDLLStorageClass(getDecodedDLLStorageClass(Record[11]));
3391   else
3392     upgradeDLLImportExportLinkage(Func, RawLinkage);
3393 
3394   if (Record.size() > 12) {
3395     if (unsigned ComdatID = Record[12]) {
3396       if (ComdatID > ComdatList.size())
3397         return error("Invalid function comdat ID");
3398       Func->setComdat(ComdatList[ComdatID - 1]);
3399     }
3400   } else if (hasImplicitComdat(RawLinkage)) {
3401     Func->setComdat(reinterpret_cast<Comdat *>(1));
3402   }
3403 
3404   if (Record.size() > 13 && Record[13] != 0)
3405     FunctionPrefixes.push_back(std::make_pair(Func, Record[13] - 1));
3406 
3407   if (Record.size() > 14 && Record[14] != 0)
3408     FunctionPersonalityFns.push_back(std::make_pair(Func, Record[14] - 1));
3409 
3410   if (Record.size() > 15) {
3411     Func->setDSOLocal(getDecodedDSOLocal(Record[15]));
3412   }
3413   inferDSOLocal(Func);
3414 
3415   // Record[16] is the address space number.
3416 
3417   // Check whether we have enough values to read a partition name. Also make
3418   // sure Strtab has enough values.
3419   if (Record.size() > 18 && Strtab.data() &&
3420       Record[17] + Record[18] <= Strtab.size()) {
3421     Func->setPartition(StringRef(Strtab.data() + Record[17], Record[18]));
3422   }
3423 
3424   ValueList.push_back(Func);
3425 
3426   // If this is a function with a body, remember the prototype we are
3427   // creating now, so that we can match up the body with them later.
3428   if (!isProto) {
3429     Func->setIsMaterializable(true);
3430     FunctionsWithBodies.push_back(Func);
3431     DeferredFunctionInfo[Func] = 0;
3432   }
3433   return Error::success();
3434 }
3435 
3436 Error BitcodeReader::parseGlobalIndirectSymbolRecord(
3437     unsigned BitCode, ArrayRef<uint64_t> Record) {
3438   // v1 ALIAS_OLD: [alias type, aliasee val#, linkage] (name in VST)
3439   // v1 ALIAS: [alias type, addrspace, aliasee val#, linkage, visibility,
3440   // dllstorageclass, threadlocal, unnamed_addr,
3441   // preemption specifier] (name in VST)
3442   // v1 IFUNC: [alias type, addrspace, aliasee val#, linkage,
3443   // visibility, dllstorageclass, threadlocal, unnamed_addr,
3444   // preemption specifier] (name in VST)
3445   // v2: [strtab_offset, strtab_size, v1]
3446   StringRef Name;
3447   std::tie(Name, Record) = readNameFromStrtab(Record);
3448 
3449   bool NewRecord = BitCode != bitc::MODULE_CODE_ALIAS_OLD;
3450   if (Record.size() < (3 + (unsigned)NewRecord))
3451     return error("Invalid record");
3452   unsigned OpNum = 0;
3453   Type *Ty = getTypeByID(Record[OpNum++]);
3454   if (!Ty)
3455     return error("Invalid record");
3456 
3457   unsigned AddrSpace;
3458   if (!NewRecord) {
3459     auto *PTy = dyn_cast<PointerType>(Ty);
3460     if (!PTy)
3461       return error("Invalid type for value");
3462     Ty = PTy->getElementType();
3463     AddrSpace = PTy->getAddressSpace();
3464   } else {
3465     AddrSpace = Record[OpNum++];
3466   }
3467 
3468   auto Val = Record[OpNum++];
3469   auto Linkage = Record[OpNum++];
3470   GlobalIndirectSymbol *NewGA;
3471   if (BitCode == bitc::MODULE_CODE_ALIAS ||
3472       BitCode == bitc::MODULE_CODE_ALIAS_OLD)
3473     NewGA = GlobalAlias::create(Ty, AddrSpace, getDecodedLinkage(Linkage), Name,
3474                                 TheModule);
3475   else
3476     NewGA = GlobalIFunc::create(Ty, AddrSpace, getDecodedLinkage(Linkage), Name,
3477                                 nullptr, TheModule);
3478 
3479   // Local linkage must have default visibility.
3480   // auto-upgrade `hidden` and `protected` for old bitcode.
3481   if (OpNum != Record.size()) {
3482     auto VisInd = OpNum++;
3483     if (!NewGA->hasLocalLinkage())
3484       NewGA->setVisibility(getDecodedVisibility(Record[VisInd]));
3485   }
3486   if (BitCode == bitc::MODULE_CODE_ALIAS ||
3487       BitCode == bitc::MODULE_CODE_ALIAS_OLD) {
3488     if (OpNum != Record.size())
3489       NewGA->setDLLStorageClass(getDecodedDLLStorageClass(Record[OpNum++]));
3490     else
3491       upgradeDLLImportExportLinkage(NewGA, Linkage);
3492     if (OpNum != Record.size())
3493       NewGA->setThreadLocalMode(getDecodedThreadLocalMode(Record[OpNum++]));
3494     if (OpNum != Record.size())
3495       NewGA->setUnnamedAddr(getDecodedUnnamedAddrType(Record[OpNum++]));
3496   }
3497   if (OpNum != Record.size())
3498     NewGA->setDSOLocal(getDecodedDSOLocal(Record[OpNum++]));
3499   inferDSOLocal(NewGA);
3500 
3501   // Check whether we have enough values to read a partition name.
3502   if (OpNum + 1 < Record.size()) {
3503     NewGA->setPartition(
3504         StringRef(Strtab.data() + Record[OpNum], Record[OpNum + 1]));
3505     OpNum += 2;
3506   }
3507 
3508   ValueList.push_back(NewGA);
3509   IndirectSymbolInits.push_back(std::make_pair(NewGA, Val));
3510   return Error::success();
3511 }
3512 
3513 Error BitcodeReader::parseModule(uint64_t ResumeBit,
3514                                  bool ShouldLazyLoadMetadata,
3515                                  DataLayoutCallbackTy DataLayoutCallback) {
3516   if (ResumeBit) {
3517     if (Error JumpFailed = Stream.JumpToBit(ResumeBit))
3518       return JumpFailed;
3519   } else if (Error Err = Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
3520     return Err;
3521 
3522   SmallVector<uint64_t, 64> Record;
3523 
3524   // Parts of bitcode parsing depend on the datalayout.  Make sure we
3525   // finalize the datalayout before we run any of that code.
3526   bool ResolvedDataLayout = false;
3527   auto ResolveDataLayout = [&] {
3528     if (ResolvedDataLayout)
3529       return;
3530 
3531     // datalayout and triple can't be parsed after this point.
3532     ResolvedDataLayout = true;
3533 
3534     // Upgrade data layout string.
3535     std::string DL = llvm::UpgradeDataLayoutString(
3536         TheModule->getDataLayoutStr(), TheModule->getTargetTriple());
3537     TheModule->setDataLayout(DL);
3538 
3539     if (auto LayoutOverride =
3540             DataLayoutCallback(TheModule->getTargetTriple()))
3541       TheModule->setDataLayout(*LayoutOverride);
3542   };
3543 
3544   // Read all the records for this module.
3545   while (true) {
3546     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
3547     if (!MaybeEntry)
3548       return MaybeEntry.takeError();
3549     llvm::BitstreamEntry Entry = MaybeEntry.get();
3550 
3551     switch (Entry.Kind) {
3552     case BitstreamEntry::Error:
3553       return error("Malformed block");
3554     case BitstreamEntry::EndBlock:
3555       ResolveDataLayout();
3556       return globalCleanup();
3557 
3558     case BitstreamEntry::SubBlock:
3559       switch (Entry.ID) {
3560       default:  // Skip unknown content.
3561         if (Error Err = Stream.SkipBlock())
3562           return Err;
3563         break;
3564       case bitc::BLOCKINFO_BLOCK_ID:
3565         if (readBlockInfo())
3566           return error("Malformed block");
3567         break;
3568       case bitc::PARAMATTR_BLOCK_ID:
3569         if (Error Err = parseAttributeBlock())
3570           return Err;
3571         break;
3572       case bitc::PARAMATTR_GROUP_BLOCK_ID:
3573         if (Error Err = parseAttributeGroupBlock())
3574           return Err;
3575         break;
3576       case bitc::TYPE_BLOCK_ID_NEW:
3577         if (Error Err = parseTypeTable())
3578           return Err;
3579         break;
3580       case bitc::VALUE_SYMTAB_BLOCK_ID:
3581         if (!SeenValueSymbolTable) {
3582           // Either this is an old form VST without function index and an
3583           // associated VST forward declaration record (which would have caused
3584           // the VST to be jumped to and parsed before it was encountered
3585           // normally in the stream), or there were no function blocks to
3586           // trigger an earlier parsing of the VST.
3587           assert(VSTOffset == 0 || FunctionsWithBodies.empty());
3588           if (Error Err = parseValueSymbolTable())
3589             return Err;
3590           SeenValueSymbolTable = true;
3591         } else {
3592           // We must have had a VST forward declaration record, which caused
3593           // the parser to jump to and parse the VST earlier.
3594           assert(VSTOffset > 0);
3595           if (Error Err = Stream.SkipBlock())
3596             return Err;
3597         }
3598         break;
3599       case bitc::CONSTANTS_BLOCK_ID:
3600         if (Error Err = parseConstants())
3601           return Err;
3602         if (Error Err = resolveGlobalAndIndirectSymbolInits())
3603           return Err;
3604         break;
3605       case bitc::METADATA_BLOCK_ID:
3606         if (ShouldLazyLoadMetadata) {
3607           if (Error Err = rememberAndSkipMetadata())
3608             return Err;
3609           break;
3610         }
3611         assert(DeferredMetadataInfo.empty() && "Unexpected deferred metadata");
3612         if (Error Err = MDLoader->parseModuleMetadata())
3613           return Err;
3614         break;
3615       case bitc::METADATA_KIND_BLOCK_ID:
3616         if (Error Err = MDLoader->parseMetadataKinds())
3617           return Err;
3618         break;
3619       case bitc::FUNCTION_BLOCK_ID:
3620         ResolveDataLayout();
3621 
3622         // If this is the first function body we've seen, reverse the
3623         // FunctionsWithBodies list.
3624         if (!SeenFirstFunctionBody) {
3625           std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
3626           if (Error Err = globalCleanup())
3627             return Err;
3628           SeenFirstFunctionBody = true;
3629         }
3630 
3631         if (VSTOffset > 0) {
3632           // If we have a VST forward declaration record, make sure we
3633           // parse the VST now if we haven't already. It is needed to
3634           // set up the DeferredFunctionInfo vector for lazy reading.
3635           if (!SeenValueSymbolTable) {
3636             if (Error Err = BitcodeReader::parseValueSymbolTable(VSTOffset))
3637               return Err;
3638             SeenValueSymbolTable = true;
3639             // Fall through so that we record the NextUnreadBit below.
3640             // This is necessary in case we have an anonymous function that
3641             // is later materialized. Since it will not have a VST entry we
3642             // need to fall back to the lazy parse to find its offset.
3643           } else {
3644             // If we have a VST forward declaration record, but have already
3645             // parsed the VST (just above, when the first function body was
3646             // encountered here), then we are resuming the parse after
3647             // materializing functions. The ResumeBit points to the
3648             // start of the last function block recorded in the
3649             // DeferredFunctionInfo map. Skip it.
3650             if (Error Err = Stream.SkipBlock())
3651               return Err;
3652             continue;
3653           }
3654         }
3655 
3656         // Support older bitcode files that did not have the function
3657         // index in the VST, nor a VST forward declaration record, as
3658         // well as anonymous functions that do not have VST entries.
3659         // Build the DeferredFunctionInfo vector on the fly.
3660         if (Error Err = rememberAndSkipFunctionBody())
3661           return Err;
3662 
3663         // Suspend parsing when we reach the function bodies. Subsequent
3664         // materialization calls will resume it when necessary. If the bitcode
3665         // file is old, the symbol table will be at the end instead and will not
3666         // have been seen yet. In this case, just finish the parse now.
3667         if (SeenValueSymbolTable) {
3668           NextUnreadBit = Stream.GetCurrentBitNo();
3669           // After the VST has been parsed, we need to make sure intrinsic name
3670           // are auto-upgraded.
3671           return globalCleanup();
3672         }
3673         break;
3674       case bitc::USELIST_BLOCK_ID:
3675         if (Error Err = parseUseLists())
3676           return Err;
3677         break;
3678       case bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID:
3679         if (Error Err = parseOperandBundleTags())
3680           return Err;
3681         break;
3682       case bitc::SYNC_SCOPE_NAMES_BLOCK_ID:
3683         if (Error Err = parseSyncScopeNames())
3684           return Err;
3685         break;
3686       }
3687       continue;
3688 
3689     case BitstreamEntry::Record:
3690       // The interesting case.
3691       break;
3692     }
3693 
3694     // Read a record.
3695     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
3696     if (!MaybeBitCode)
3697       return MaybeBitCode.takeError();
3698     switch (unsigned BitCode = MaybeBitCode.get()) {
3699     default: break;  // Default behavior, ignore unknown content.
3700     case bitc::MODULE_CODE_VERSION: {
3701       Expected<unsigned> VersionOrErr = parseVersionRecord(Record);
3702       if (!VersionOrErr)
3703         return VersionOrErr.takeError();
3704       UseRelativeIDs = *VersionOrErr >= 1;
3705       break;
3706     }
3707     case bitc::MODULE_CODE_TRIPLE: {  // TRIPLE: [strchr x N]
3708       if (ResolvedDataLayout)
3709         return error("target triple too late in module");
3710       std::string S;
3711       if (convertToString(Record, 0, S))
3712         return error("Invalid record");
3713       TheModule->setTargetTriple(S);
3714       break;
3715     }
3716     case bitc::MODULE_CODE_DATALAYOUT: {  // DATALAYOUT: [strchr x N]
3717       if (ResolvedDataLayout)
3718         return error("datalayout too late in module");
3719       std::string S;
3720       if (convertToString(Record, 0, S))
3721         return error("Invalid record");
3722       TheModule->setDataLayout(S);
3723       break;
3724     }
3725     case bitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
3726       std::string S;
3727       if (convertToString(Record, 0, S))
3728         return error("Invalid record");
3729       TheModule->setModuleInlineAsm(S);
3730       break;
3731     }
3732     case bitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strchr x N]
3733       // Deprecated, but still needed to read old bitcode files.
3734       std::string S;
3735       if (convertToString(Record, 0, S))
3736         return error("Invalid record");
3737       // Ignore value.
3738       break;
3739     }
3740     case bitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
3741       std::string S;
3742       if (convertToString(Record, 0, S))
3743         return error("Invalid record");
3744       SectionTable.push_back(S);
3745       break;
3746     }
3747     case bitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
3748       std::string S;
3749       if (convertToString(Record, 0, S))
3750         return error("Invalid record");
3751       GCTable.push_back(S);
3752       break;
3753     }
3754     case bitc::MODULE_CODE_COMDAT:
3755       if (Error Err = parseComdatRecord(Record))
3756         return Err;
3757       break;
3758     case bitc::MODULE_CODE_GLOBALVAR:
3759       if (Error Err = parseGlobalVarRecord(Record))
3760         return Err;
3761       break;
3762     case bitc::MODULE_CODE_FUNCTION:
3763       ResolveDataLayout();
3764       if (Error Err = parseFunctionRecord(Record))
3765         return Err;
3766       break;
3767     case bitc::MODULE_CODE_IFUNC:
3768     case bitc::MODULE_CODE_ALIAS:
3769     case bitc::MODULE_CODE_ALIAS_OLD:
3770       if (Error Err = parseGlobalIndirectSymbolRecord(BitCode, Record))
3771         return Err;
3772       break;
3773     /// MODULE_CODE_VSTOFFSET: [offset]
3774     case bitc::MODULE_CODE_VSTOFFSET:
3775       if (Record.empty())
3776         return error("Invalid record");
3777       // Note that we subtract 1 here because the offset is relative to one word
3778       // before the start of the identification or module block, which was
3779       // historically always the start of the regular bitcode header.
3780       VSTOffset = Record[0] - 1;
3781       break;
3782     /// MODULE_CODE_SOURCE_FILENAME: [namechar x N]
3783     case bitc::MODULE_CODE_SOURCE_FILENAME:
3784       SmallString<128> ValueName;
3785       if (convertToString(Record, 0, ValueName))
3786         return error("Invalid record");
3787       TheModule->setSourceFileName(ValueName);
3788       break;
3789     }
3790     Record.clear();
3791   }
3792 }
3793 
3794 Error BitcodeReader::parseBitcodeInto(Module *M, bool ShouldLazyLoadMetadata,
3795                                       bool IsImporting,
3796                                       DataLayoutCallbackTy DataLayoutCallback) {
3797   TheModule = M;
3798   MDLoader = MetadataLoader(Stream, *M, ValueList, IsImporting,
3799                             [&](unsigned ID) { return getTypeByID(ID); });
3800   return parseModule(0, ShouldLazyLoadMetadata, DataLayoutCallback);
3801 }
3802 
3803 Error BitcodeReader::typeCheckLoadStoreInst(Type *ValType, Type *PtrType) {
3804   if (!isa<PointerType>(PtrType))
3805     return error("Load/Store operand is not a pointer type");
3806 
3807   if (!cast<PointerType>(PtrType)->isOpaqueOrPointeeTypeMatches(ValType))
3808     return error("Explicit load/store type does not match pointee "
3809                  "type of pointer operand");
3810   if (!PointerType::isLoadableOrStorableType(ValType))
3811     return error("Cannot load/store from pointer");
3812   return Error::success();
3813 }
3814 
3815 void BitcodeReader::propagateAttributeTypes(CallBase *CB,
3816                                             ArrayRef<Type *> ArgsTys) {
3817   for (unsigned i = 0; i != CB->arg_size(); ++i) {
3818     for (Attribute::AttrKind Kind : {Attribute::ByVal, Attribute::StructRet,
3819                                      Attribute::InAlloca}) {
3820       if (!CB->paramHasAttr(i, Kind))
3821         continue;
3822 
3823       CB->removeParamAttr(i, Kind);
3824 
3825       Type *PtrEltTy = cast<PointerType>(ArgsTys[i])->getElementType();
3826       Attribute NewAttr;
3827       switch (Kind) {
3828       case Attribute::ByVal:
3829         NewAttr = Attribute::getWithByValType(Context, PtrEltTy);
3830         break;
3831       case Attribute::StructRet:
3832         NewAttr = Attribute::getWithStructRetType(Context, PtrEltTy);
3833         break;
3834       case Attribute::InAlloca:
3835         NewAttr = Attribute::getWithInAllocaType(Context, PtrEltTy);
3836         break;
3837       default:
3838         llvm_unreachable("not an upgraded type attribute");
3839       }
3840 
3841       CB->addParamAttr(i, NewAttr);
3842     }
3843   }
3844 
3845   switch (CB->getIntrinsicID()) {
3846   case Intrinsic::preserve_array_access_index:
3847   case Intrinsic::preserve_struct_access_index:
3848     if (!CB->getAttributes().getParamElementType(0)) {
3849       Type *ElTy = cast<PointerType>(ArgsTys[0])->getElementType();
3850       Attribute NewAttr = Attribute::get(Context, Attribute::ElementType, ElTy);
3851       CB->addParamAttr(0, NewAttr);
3852     }
3853     break;
3854   default:
3855     break;
3856   }
3857 }
3858 
3859 /// Lazily parse the specified function body block.
3860 Error BitcodeReader::parseFunctionBody(Function *F) {
3861   if (Error Err = Stream.EnterSubBlock(bitc::FUNCTION_BLOCK_ID))
3862     return Err;
3863 
3864   // Unexpected unresolved metadata when parsing function.
3865   if (MDLoader->hasFwdRefs())
3866     return error("Invalid function metadata: incoming forward references");
3867 
3868   InstructionList.clear();
3869   unsigned ModuleValueListSize = ValueList.size();
3870   unsigned ModuleMDLoaderSize = MDLoader->size();
3871 
3872   // Add all the function arguments to the value table.
3873 #ifndef NDEBUG
3874   unsigned ArgNo = 0;
3875   FunctionType *FTy = FunctionTypes[F];
3876 #endif
3877   for (Argument &I : F->args()) {
3878     assert(I.getType() == FTy->getParamType(ArgNo++) &&
3879            "Incorrect fully specified type for Function Argument");
3880     ValueList.push_back(&I);
3881   }
3882   unsigned NextValueNo = ValueList.size();
3883   BasicBlock *CurBB = nullptr;
3884   unsigned CurBBNo = 0;
3885 
3886   DebugLoc LastLoc;
3887   auto getLastInstruction = [&]() -> Instruction * {
3888     if (CurBB && !CurBB->empty())
3889       return &CurBB->back();
3890     else if (CurBBNo && FunctionBBs[CurBBNo - 1] &&
3891              !FunctionBBs[CurBBNo - 1]->empty())
3892       return &FunctionBBs[CurBBNo - 1]->back();
3893     return nullptr;
3894   };
3895 
3896   std::vector<OperandBundleDef> OperandBundles;
3897 
3898   // Read all the records.
3899   SmallVector<uint64_t, 64> Record;
3900 
3901   while (true) {
3902     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
3903     if (!MaybeEntry)
3904       return MaybeEntry.takeError();
3905     llvm::BitstreamEntry Entry = MaybeEntry.get();
3906 
3907     switch (Entry.Kind) {
3908     case BitstreamEntry::Error:
3909       return error("Malformed block");
3910     case BitstreamEntry::EndBlock:
3911       goto OutOfRecordLoop;
3912 
3913     case BitstreamEntry::SubBlock:
3914       switch (Entry.ID) {
3915       default:  // Skip unknown content.
3916         if (Error Err = Stream.SkipBlock())
3917           return Err;
3918         break;
3919       case bitc::CONSTANTS_BLOCK_ID:
3920         if (Error Err = parseConstants())
3921           return Err;
3922         NextValueNo = ValueList.size();
3923         break;
3924       case bitc::VALUE_SYMTAB_BLOCK_ID:
3925         if (Error Err = parseValueSymbolTable())
3926           return Err;
3927         break;
3928       case bitc::METADATA_ATTACHMENT_ID:
3929         if (Error Err = MDLoader->parseMetadataAttachment(*F, InstructionList))
3930           return Err;
3931         break;
3932       case bitc::METADATA_BLOCK_ID:
3933         assert(DeferredMetadataInfo.empty() &&
3934                "Must read all module-level metadata before function-level");
3935         if (Error Err = MDLoader->parseFunctionMetadata())
3936           return Err;
3937         break;
3938       case bitc::USELIST_BLOCK_ID:
3939         if (Error Err = parseUseLists())
3940           return Err;
3941         break;
3942       }
3943       continue;
3944 
3945     case BitstreamEntry::Record:
3946       // The interesting case.
3947       break;
3948     }
3949 
3950     // Read a record.
3951     Record.clear();
3952     Instruction *I = nullptr;
3953     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
3954     if (!MaybeBitCode)
3955       return MaybeBitCode.takeError();
3956     switch (unsigned BitCode = MaybeBitCode.get()) {
3957     default: // Default behavior: reject
3958       return error("Invalid value");
3959     case bitc::FUNC_CODE_DECLAREBLOCKS: {   // DECLAREBLOCKS: [nblocks]
3960       if (Record.empty() || Record[0] == 0)
3961         return error("Invalid record");
3962       // Create all the basic blocks for the function.
3963       FunctionBBs.resize(Record[0]);
3964 
3965       // See if anything took the address of blocks in this function.
3966       auto BBFRI = BasicBlockFwdRefs.find(F);
3967       if (BBFRI == BasicBlockFwdRefs.end()) {
3968         for (unsigned i = 0, e = FunctionBBs.size(); i != e; ++i)
3969           FunctionBBs[i] = BasicBlock::Create(Context, "", F);
3970       } else {
3971         auto &BBRefs = BBFRI->second;
3972         // Check for invalid basic block references.
3973         if (BBRefs.size() > FunctionBBs.size())
3974           return error("Invalid ID");
3975         assert(!BBRefs.empty() && "Unexpected empty array");
3976         assert(!BBRefs.front() && "Invalid reference to entry block");
3977         for (unsigned I = 0, E = FunctionBBs.size(), RE = BBRefs.size(); I != E;
3978              ++I)
3979           if (I < RE && BBRefs[I]) {
3980             BBRefs[I]->insertInto(F);
3981             FunctionBBs[I] = BBRefs[I];
3982           } else {
3983             FunctionBBs[I] = BasicBlock::Create(Context, "", F);
3984           }
3985 
3986         // Erase from the table.
3987         BasicBlockFwdRefs.erase(BBFRI);
3988       }
3989 
3990       CurBB = FunctionBBs[0];
3991       continue;
3992     }
3993 
3994     case bitc::FUNC_CODE_DEBUG_LOC_AGAIN:  // DEBUG_LOC_AGAIN
3995       // This record indicates that the last instruction is at the same
3996       // location as the previous instruction with a location.
3997       I = getLastInstruction();
3998 
3999       if (!I)
4000         return error("Invalid record");
4001       I->setDebugLoc(LastLoc);
4002       I = nullptr;
4003       continue;
4004 
4005     case bitc::FUNC_CODE_DEBUG_LOC: {      // DEBUG_LOC: [line, col, scope, ia]
4006       I = getLastInstruction();
4007       if (!I || Record.size() < 4)
4008         return error("Invalid record");
4009 
4010       unsigned Line = Record[0], Col = Record[1];
4011       unsigned ScopeID = Record[2], IAID = Record[3];
4012       bool isImplicitCode = Record.size() == 5 && Record[4];
4013 
4014       MDNode *Scope = nullptr, *IA = nullptr;
4015       if (ScopeID) {
4016         Scope = dyn_cast_or_null<MDNode>(
4017             MDLoader->getMetadataFwdRefOrLoad(ScopeID - 1));
4018         if (!Scope)
4019           return error("Invalid record");
4020       }
4021       if (IAID) {
4022         IA = dyn_cast_or_null<MDNode>(
4023             MDLoader->getMetadataFwdRefOrLoad(IAID - 1));
4024         if (!IA)
4025           return error("Invalid record");
4026       }
4027       LastLoc = DILocation::get(Scope->getContext(), Line, Col, Scope, IA,
4028                                 isImplicitCode);
4029       I->setDebugLoc(LastLoc);
4030       I = nullptr;
4031       continue;
4032     }
4033     case bitc::FUNC_CODE_INST_UNOP: {    // UNOP: [opval, ty, opcode]
4034       unsigned OpNum = 0;
4035       Value *LHS;
4036       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
4037           OpNum+1 > Record.size())
4038         return error("Invalid record");
4039 
4040       int Opc = getDecodedUnaryOpcode(Record[OpNum++], LHS->getType());
4041       if (Opc == -1)
4042         return error("Invalid record");
4043       I = UnaryOperator::Create((Instruction::UnaryOps)Opc, LHS);
4044       InstructionList.push_back(I);
4045       if (OpNum < Record.size()) {
4046         if (isa<FPMathOperator>(I)) {
4047           FastMathFlags FMF = getDecodedFastMathFlags(Record[OpNum]);
4048           if (FMF.any())
4049             I->setFastMathFlags(FMF);
4050         }
4051       }
4052       break;
4053     }
4054     case bitc::FUNC_CODE_INST_BINOP: {    // BINOP: [opval, ty, opval, opcode]
4055       unsigned OpNum = 0;
4056       Value *LHS, *RHS;
4057       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
4058           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS) ||
4059           OpNum+1 > Record.size())
4060         return error("Invalid record");
4061 
4062       int Opc = getDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
4063       if (Opc == -1)
4064         return error("Invalid record");
4065       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
4066       InstructionList.push_back(I);
4067       if (OpNum < Record.size()) {
4068         if (Opc == Instruction::Add ||
4069             Opc == Instruction::Sub ||
4070             Opc == Instruction::Mul ||
4071             Opc == Instruction::Shl) {
4072           if (Record[OpNum] & (1 << bitc::OBO_NO_SIGNED_WRAP))
4073             cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
4074           if (Record[OpNum] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
4075             cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
4076         } else if (Opc == Instruction::SDiv ||
4077                    Opc == Instruction::UDiv ||
4078                    Opc == Instruction::LShr ||
4079                    Opc == Instruction::AShr) {
4080           if (Record[OpNum] & (1 << bitc::PEO_EXACT))
4081             cast<BinaryOperator>(I)->setIsExact(true);
4082         } else if (isa<FPMathOperator>(I)) {
4083           FastMathFlags FMF = getDecodedFastMathFlags(Record[OpNum]);
4084           if (FMF.any())
4085             I->setFastMathFlags(FMF);
4086         }
4087 
4088       }
4089       break;
4090     }
4091     case bitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, opty, destty, castopc]
4092       unsigned OpNum = 0;
4093       Value *Op;
4094       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
4095           OpNum+2 != Record.size())
4096         return error("Invalid record");
4097 
4098       Type *ResTy = getTypeByID(Record[OpNum]);
4099       int Opc = getDecodedCastOpcode(Record[OpNum + 1]);
4100       if (Opc == -1 || !ResTy)
4101         return error("Invalid record");
4102       Instruction *Temp = nullptr;
4103       if ((I = UpgradeBitCastInst(Opc, Op, ResTy, Temp))) {
4104         if (Temp) {
4105           InstructionList.push_back(Temp);
4106           assert(CurBB && "No current BB?");
4107           CurBB->getInstList().push_back(Temp);
4108         }
4109       } else {
4110         auto CastOp = (Instruction::CastOps)Opc;
4111         if (!CastInst::castIsValid(CastOp, Op, ResTy))
4112           return error("Invalid cast");
4113         I = CastInst::Create(CastOp, Op, ResTy);
4114       }
4115       InstructionList.push_back(I);
4116       break;
4117     }
4118     case bitc::FUNC_CODE_INST_INBOUNDS_GEP_OLD:
4119     case bitc::FUNC_CODE_INST_GEP_OLD:
4120     case bitc::FUNC_CODE_INST_GEP: { // GEP: type, [n x operands]
4121       unsigned OpNum = 0;
4122 
4123       Type *Ty;
4124       bool InBounds;
4125 
4126       if (BitCode == bitc::FUNC_CODE_INST_GEP) {
4127         InBounds = Record[OpNum++];
4128         Ty = getTypeByID(Record[OpNum++]);
4129       } else {
4130         InBounds = BitCode == bitc::FUNC_CODE_INST_INBOUNDS_GEP_OLD;
4131         Ty = nullptr;
4132       }
4133 
4134       Value *BasePtr;
4135       if (getValueTypePair(Record, OpNum, NextValueNo, BasePtr))
4136         return error("Invalid record");
4137 
4138       if (!Ty) {
4139         Ty = cast<PointerType>(BasePtr->getType()->getScalarType())
4140                  ->getElementType();
4141       } else if (!cast<PointerType>(BasePtr->getType()->getScalarType())
4142                       ->isOpaqueOrPointeeTypeMatches(Ty)) {
4143         return error(
4144             "Explicit gep type does not match pointee type of pointer operand");
4145       }
4146 
4147       SmallVector<Value*, 16> GEPIdx;
4148       while (OpNum != Record.size()) {
4149         Value *Op;
4150         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
4151           return error("Invalid record");
4152         GEPIdx.push_back(Op);
4153       }
4154 
4155       I = GetElementPtrInst::Create(Ty, BasePtr, GEPIdx);
4156 
4157       InstructionList.push_back(I);
4158       if (InBounds)
4159         cast<GetElementPtrInst>(I)->setIsInBounds(true);
4160       break;
4161     }
4162 
4163     case bitc::FUNC_CODE_INST_EXTRACTVAL: {
4164                                        // EXTRACTVAL: [opty, opval, n x indices]
4165       unsigned OpNum = 0;
4166       Value *Agg;
4167       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
4168         return error("Invalid record");
4169       Type *Ty = Agg->getType();
4170 
4171       unsigned RecSize = Record.size();
4172       if (OpNum == RecSize)
4173         return error("EXTRACTVAL: Invalid instruction with 0 indices");
4174 
4175       SmallVector<unsigned, 4> EXTRACTVALIdx;
4176       for (; OpNum != RecSize; ++OpNum) {
4177         bool IsArray = Ty->isArrayTy();
4178         bool IsStruct = Ty->isStructTy();
4179         uint64_t Index = Record[OpNum];
4180 
4181         if (!IsStruct && !IsArray)
4182           return error("EXTRACTVAL: Invalid type");
4183         if ((unsigned)Index != Index)
4184           return error("Invalid value");
4185         if (IsStruct && Index >= Ty->getStructNumElements())
4186           return error("EXTRACTVAL: Invalid struct index");
4187         if (IsArray && Index >= Ty->getArrayNumElements())
4188           return error("EXTRACTVAL: Invalid array index");
4189         EXTRACTVALIdx.push_back((unsigned)Index);
4190 
4191         if (IsStruct)
4192           Ty = Ty->getStructElementType(Index);
4193         else
4194           Ty = Ty->getArrayElementType();
4195       }
4196 
4197       I = ExtractValueInst::Create(Agg, EXTRACTVALIdx);
4198       InstructionList.push_back(I);
4199       break;
4200     }
4201 
4202     case bitc::FUNC_CODE_INST_INSERTVAL: {
4203                            // INSERTVAL: [opty, opval, opty, opval, n x indices]
4204       unsigned OpNum = 0;
4205       Value *Agg;
4206       if (getValueTypePair(Record, OpNum, NextValueNo, Agg))
4207         return error("Invalid record");
4208       Value *Val;
4209       if (getValueTypePair(Record, OpNum, NextValueNo, Val))
4210         return error("Invalid record");
4211 
4212       unsigned RecSize = Record.size();
4213       if (OpNum == RecSize)
4214         return error("INSERTVAL: Invalid instruction with 0 indices");
4215 
4216       SmallVector<unsigned, 4> INSERTVALIdx;
4217       Type *CurTy = Agg->getType();
4218       for (; OpNum != RecSize; ++OpNum) {
4219         bool IsArray = CurTy->isArrayTy();
4220         bool IsStruct = CurTy->isStructTy();
4221         uint64_t Index = Record[OpNum];
4222 
4223         if (!IsStruct && !IsArray)
4224           return error("INSERTVAL: Invalid type");
4225         if ((unsigned)Index != Index)
4226           return error("Invalid value");
4227         if (IsStruct && Index >= CurTy->getStructNumElements())
4228           return error("INSERTVAL: Invalid struct index");
4229         if (IsArray && Index >= CurTy->getArrayNumElements())
4230           return error("INSERTVAL: Invalid array index");
4231 
4232         INSERTVALIdx.push_back((unsigned)Index);
4233         if (IsStruct)
4234           CurTy = CurTy->getStructElementType(Index);
4235         else
4236           CurTy = CurTy->getArrayElementType();
4237       }
4238 
4239       if (CurTy != Val->getType())
4240         return error("Inserted value type doesn't match aggregate type");
4241 
4242       I = InsertValueInst::Create(Agg, Val, INSERTVALIdx);
4243       InstructionList.push_back(I);
4244       break;
4245     }
4246 
4247     case bitc::FUNC_CODE_INST_SELECT: { // SELECT: [opval, ty, opval, opval]
4248       // obsolete form of select
4249       // handles select i1 ... in old bitcode
4250       unsigned OpNum = 0;
4251       Value *TrueVal, *FalseVal, *Cond;
4252       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
4253           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
4254           popValue(Record, OpNum, NextValueNo, Type::getInt1Ty(Context), Cond))
4255         return error("Invalid record");
4256 
4257       I = SelectInst::Create(Cond, TrueVal, FalseVal);
4258       InstructionList.push_back(I);
4259       break;
4260     }
4261 
4262     case bitc::FUNC_CODE_INST_VSELECT: {// VSELECT: [ty,opval,opval,predty,pred]
4263       // new form of select
4264       // handles select i1 or select [N x i1]
4265       unsigned OpNum = 0;
4266       Value *TrueVal, *FalseVal, *Cond;
4267       if (getValueTypePair(Record, OpNum, NextValueNo, TrueVal) ||
4268           popValue(Record, OpNum, NextValueNo, TrueVal->getType(), FalseVal) ||
4269           getValueTypePair(Record, OpNum, NextValueNo, Cond))
4270         return error("Invalid record");
4271 
4272       // select condition can be either i1 or [N x i1]
4273       if (VectorType* vector_type =
4274           dyn_cast<VectorType>(Cond->getType())) {
4275         // expect <n x i1>
4276         if (vector_type->getElementType() != Type::getInt1Ty(Context))
4277           return error("Invalid type for value");
4278       } else {
4279         // expect i1
4280         if (Cond->getType() != Type::getInt1Ty(Context))
4281           return error("Invalid type for value");
4282       }
4283 
4284       I = SelectInst::Create(Cond, TrueVal, FalseVal);
4285       InstructionList.push_back(I);
4286       if (OpNum < Record.size() && isa<FPMathOperator>(I)) {
4287         FastMathFlags FMF = getDecodedFastMathFlags(Record[OpNum]);
4288         if (FMF.any())
4289           I->setFastMathFlags(FMF);
4290       }
4291       break;
4292     }
4293 
4294     case bitc::FUNC_CODE_INST_EXTRACTELT: { // EXTRACTELT: [opty, opval, opval]
4295       unsigned OpNum = 0;
4296       Value *Vec, *Idx;
4297       if (getValueTypePair(Record, OpNum, NextValueNo, Vec) ||
4298           getValueTypePair(Record, OpNum, NextValueNo, Idx))
4299         return error("Invalid record");
4300       if (!Vec->getType()->isVectorTy())
4301         return error("Invalid type for value");
4302       I = ExtractElementInst::Create(Vec, Idx);
4303       InstructionList.push_back(I);
4304       break;
4305     }
4306 
4307     case bitc::FUNC_CODE_INST_INSERTELT: { // INSERTELT: [ty, opval,opval,opval]
4308       unsigned OpNum = 0;
4309       Value *Vec, *Elt, *Idx;
4310       if (getValueTypePair(Record, OpNum, NextValueNo, Vec))
4311         return error("Invalid record");
4312       if (!Vec->getType()->isVectorTy())
4313         return error("Invalid type for value");
4314       if (popValue(Record, OpNum, NextValueNo,
4315                    cast<VectorType>(Vec->getType())->getElementType(), Elt) ||
4316           getValueTypePair(Record, OpNum, NextValueNo, Idx))
4317         return error("Invalid record");
4318       I = InsertElementInst::Create(Vec, Elt, Idx);
4319       InstructionList.push_back(I);
4320       break;
4321     }
4322 
4323     case bitc::FUNC_CODE_INST_SHUFFLEVEC: {// SHUFFLEVEC: [opval,ty,opval,opval]
4324       unsigned OpNum = 0;
4325       Value *Vec1, *Vec2, *Mask;
4326       if (getValueTypePair(Record, OpNum, NextValueNo, Vec1) ||
4327           popValue(Record, OpNum, NextValueNo, Vec1->getType(), Vec2))
4328         return error("Invalid record");
4329 
4330       if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
4331         return error("Invalid record");
4332       if (!Vec1->getType()->isVectorTy() || !Vec2->getType()->isVectorTy())
4333         return error("Invalid type for value");
4334 
4335       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
4336       InstructionList.push_back(I);
4337       break;
4338     }
4339 
4340     case bitc::FUNC_CODE_INST_CMP:   // CMP: [opty, opval, opval, pred]
4341       // Old form of ICmp/FCmp returning bool
4342       // Existed to differentiate between icmp/fcmp and vicmp/vfcmp which were
4343       // both legal on vectors but had different behaviour.
4344     case bitc::FUNC_CODE_INST_CMP2: { // CMP2: [opty, opval, opval, pred]
4345       // FCmp/ICmp returning bool or vector of bool
4346 
4347       unsigned OpNum = 0;
4348       Value *LHS, *RHS;
4349       if (getValueTypePair(Record, OpNum, NextValueNo, LHS) ||
4350           popValue(Record, OpNum, NextValueNo, LHS->getType(), RHS))
4351         return error("Invalid record");
4352 
4353       if (OpNum >= Record.size())
4354         return error(
4355             "Invalid record: operand number exceeded available operands");
4356 
4357       unsigned PredVal = Record[OpNum];
4358       bool IsFP = LHS->getType()->isFPOrFPVectorTy();
4359       FastMathFlags FMF;
4360       if (IsFP && Record.size() > OpNum+1)
4361         FMF = getDecodedFastMathFlags(Record[++OpNum]);
4362 
4363       if (OpNum+1 != Record.size())
4364         return error("Invalid record");
4365 
4366       if (LHS->getType()->isFPOrFPVectorTy())
4367         I = new FCmpInst((FCmpInst::Predicate)PredVal, LHS, RHS);
4368       else
4369         I = new ICmpInst((ICmpInst::Predicate)PredVal, LHS, RHS);
4370 
4371       if (FMF.any())
4372         I->setFastMathFlags(FMF);
4373       InstructionList.push_back(I);
4374       break;
4375     }
4376 
4377     case bitc::FUNC_CODE_INST_RET: // RET: [opty,opval<optional>]
4378       {
4379         unsigned Size = Record.size();
4380         if (Size == 0) {
4381           I = ReturnInst::Create(Context);
4382           InstructionList.push_back(I);
4383           break;
4384         }
4385 
4386         unsigned OpNum = 0;
4387         Value *Op = nullptr;
4388         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
4389           return error("Invalid record");
4390         if (OpNum != Record.size())
4391           return error("Invalid record");
4392 
4393         I = ReturnInst::Create(Context, Op);
4394         InstructionList.push_back(I);
4395         break;
4396       }
4397     case bitc::FUNC_CODE_INST_BR: { // BR: [bb#, bb#, opval] or [bb#]
4398       if (Record.size() != 1 && Record.size() != 3)
4399         return error("Invalid record");
4400       BasicBlock *TrueDest = getBasicBlock(Record[0]);
4401       if (!TrueDest)
4402         return error("Invalid record");
4403 
4404       if (Record.size() == 1) {
4405         I = BranchInst::Create(TrueDest);
4406         InstructionList.push_back(I);
4407       }
4408       else {
4409         BasicBlock *FalseDest = getBasicBlock(Record[1]);
4410         Value *Cond = getValue(Record, 2, NextValueNo,
4411                                Type::getInt1Ty(Context));
4412         if (!FalseDest || !Cond)
4413           return error("Invalid record");
4414         I = BranchInst::Create(TrueDest, FalseDest, Cond);
4415         InstructionList.push_back(I);
4416       }
4417       break;
4418     }
4419     case bitc::FUNC_CODE_INST_CLEANUPRET: { // CLEANUPRET: [val] or [val,bb#]
4420       if (Record.size() != 1 && Record.size() != 2)
4421         return error("Invalid record");
4422       unsigned Idx = 0;
4423       Value *CleanupPad =
4424           getValue(Record, Idx++, NextValueNo, Type::getTokenTy(Context));
4425       if (!CleanupPad)
4426         return error("Invalid record");
4427       BasicBlock *UnwindDest = nullptr;
4428       if (Record.size() == 2) {
4429         UnwindDest = getBasicBlock(Record[Idx++]);
4430         if (!UnwindDest)
4431           return error("Invalid record");
4432       }
4433 
4434       I = CleanupReturnInst::Create(CleanupPad, UnwindDest);
4435       InstructionList.push_back(I);
4436       break;
4437     }
4438     case bitc::FUNC_CODE_INST_CATCHRET: { // CATCHRET: [val,bb#]
4439       if (Record.size() != 2)
4440         return error("Invalid record");
4441       unsigned Idx = 0;
4442       Value *CatchPad =
4443           getValue(Record, Idx++, NextValueNo, Type::getTokenTy(Context));
4444       if (!CatchPad)
4445         return error("Invalid record");
4446       BasicBlock *BB = getBasicBlock(Record[Idx++]);
4447       if (!BB)
4448         return error("Invalid record");
4449 
4450       I = CatchReturnInst::Create(CatchPad, BB);
4451       InstructionList.push_back(I);
4452       break;
4453     }
4454     case bitc::FUNC_CODE_INST_CATCHSWITCH: { // CATCHSWITCH: [tok,num,(bb)*,bb?]
4455       // We must have, at minimum, the outer scope and the number of arguments.
4456       if (Record.size() < 2)
4457         return error("Invalid record");
4458 
4459       unsigned Idx = 0;
4460 
4461       Value *ParentPad =
4462           getValue(Record, Idx++, NextValueNo, Type::getTokenTy(Context));
4463 
4464       unsigned NumHandlers = Record[Idx++];
4465 
4466       SmallVector<BasicBlock *, 2> Handlers;
4467       for (unsigned Op = 0; Op != NumHandlers; ++Op) {
4468         BasicBlock *BB = getBasicBlock(Record[Idx++]);
4469         if (!BB)
4470           return error("Invalid record");
4471         Handlers.push_back(BB);
4472       }
4473 
4474       BasicBlock *UnwindDest = nullptr;
4475       if (Idx + 1 == Record.size()) {
4476         UnwindDest = getBasicBlock(Record[Idx++]);
4477         if (!UnwindDest)
4478           return error("Invalid record");
4479       }
4480 
4481       if (Record.size() != Idx)
4482         return error("Invalid record");
4483 
4484       auto *CatchSwitch =
4485           CatchSwitchInst::Create(ParentPad, UnwindDest, NumHandlers);
4486       for (BasicBlock *Handler : Handlers)
4487         CatchSwitch->addHandler(Handler);
4488       I = CatchSwitch;
4489       InstructionList.push_back(I);
4490       break;
4491     }
4492     case bitc::FUNC_CODE_INST_CATCHPAD:
4493     case bitc::FUNC_CODE_INST_CLEANUPPAD: { // [tok,num,(ty,val)*]
4494       // We must have, at minimum, the outer scope and the number of arguments.
4495       if (Record.size() < 2)
4496         return error("Invalid record");
4497 
4498       unsigned Idx = 0;
4499 
4500       Value *ParentPad =
4501           getValue(Record, Idx++, NextValueNo, Type::getTokenTy(Context));
4502 
4503       unsigned NumArgOperands = Record[Idx++];
4504 
4505       SmallVector<Value *, 2> Args;
4506       for (unsigned Op = 0; Op != NumArgOperands; ++Op) {
4507         Value *Val;
4508         if (getValueTypePair(Record, Idx, NextValueNo, Val))
4509           return error("Invalid record");
4510         Args.push_back(Val);
4511       }
4512 
4513       if (Record.size() != Idx)
4514         return error("Invalid record");
4515 
4516       if (BitCode == bitc::FUNC_CODE_INST_CLEANUPPAD)
4517         I = CleanupPadInst::Create(ParentPad, Args);
4518       else
4519         I = CatchPadInst::Create(ParentPad, Args);
4520       InstructionList.push_back(I);
4521       break;
4522     }
4523     case bitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
4524       // Check magic
4525       if ((Record[0] >> 16) == SWITCH_INST_MAGIC) {
4526         // "New" SwitchInst format with case ranges. The changes to write this
4527         // format were reverted but we still recognize bitcode that uses it.
4528         // Hopefully someday we will have support for case ranges and can use
4529         // this format again.
4530 
4531         Type *OpTy = getTypeByID(Record[1]);
4532         unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
4533 
4534         Value *Cond = getValue(Record, 2, NextValueNo, OpTy);
4535         BasicBlock *Default = getBasicBlock(Record[3]);
4536         if (!OpTy || !Cond || !Default)
4537           return error("Invalid record");
4538 
4539         unsigned NumCases = Record[4];
4540 
4541         SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
4542         InstructionList.push_back(SI);
4543 
4544         unsigned CurIdx = 5;
4545         for (unsigned i = 0; i != NumCases; ++i) {
4546           SmallVector<ConstantInt*, 1> CaseVals;
4547           unsigned NumItems = Record[CurIdx++];
4548           for (unsigned ci = 0; ci != NumItems; ++ci) {
4549             bool isSingleNumber = Record[CurIdx++];
4550 
4551             APInt Low;
4552             unsigned ActiveWords = 1;
4553             if (ValueBitWidth > 64)
4554               ActiveWords = Record[CurIdx++];
4555             Low = readWideAPInt(makeArrayRef(&Record[CurIdx], ActiveWords),
4556                                 ValueBitWidth);
4557             CurIdx += ActiveWords;
4558 
4559             if (!isSingleNumber) {
4560               ActiveWords = 1;
4561               if (ValueBitWidth > 64)
4562                 ActiveWords = Record[CurIdx++];
4563               APInt High = readWideAPInt(
4564                   makeArrayRef(&Record[CurIdx], ActiveWords), ValueBitWidth);
4565               CurIdx += ActiveWords;
4566 
4567               // FIXME: It is not clear whether values in the range should be
4568               // compared as signed or unsigned values. The partially
4569               // implemented changes that used this format in the past used
4570               // unsigned comparisons.
4571               for ( ; Low.ule(High); ++Low)
4572                 CaseVals.push_back(ConstantInt::get(Context, Low));
4573             } else
4574               CaseVals.push_back(ConstantInt::get(Context, Low));
4575           }
4576           BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
4577           for (SmallVector<ConstantInt*, 1>::iterator cvi = CaseVals.begin(),
4578                  cve = CaseVals.end(); cvi != cve; ++cvi)
4579             SI->addCase(*cvi, DestBB);
4580         }
4581         I = SI;
4582         break;
4583       }
4584 
4585       // Old SwitchInst format without case ranges.
4586 
4587       if (Record.size() < 3 || (Record.size() & 1) == 0)
4588         return error("Invalid record");
4589       Type *OpTy = getTypeByID(Record[0]);
4590       Value *Cond = getValue(Record, 1, NextValueNo, OpTy);
4591       BasicBlock *Default = getBasicBlock(Record[2]);
4592       if (!OpTy || !Cond || !Default)
4593         return error("Invalid record");
4594       unsigned NumCases = (Record.size()-3)/2;
4595       SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
4596       InstructionList.push_back(SI);
4597       for (unsigned i = 0, e = NumCases; i != e; ++i) {
4598         ConstantInt *CaseVal =
4599           dyn_cast_or_null<ConstantInt>(getFnValueByID(Record[3+i*2], OpTy));
4600         BasicBlock *DestBB = getBasicBlock(Record[1+3+i*2]);
4601         if (!CaseVal || !DestBB) {
4602           delete SI;
4603           return error("Invalid record");
4604         }
4605         SI->addCase(CaseVal, DestBB);
4606       }
4607       I = SI;
4608       break;
4609     }
4610     case bitc::FUNC_CODE_INST_INDIRECTBR: { // INDIRECTBR: [opty, op0, op1, ...]
4611       if (Record.size() < 2)
4612         return error("Invalid record");
4613       Type *OpTy = getTypeByID(Record[0]);
4614       Value *Address = getValue(Record, 1, NextValueNo, OpTy);
4615       if (!OpTy || !Address)
4616         return error("Invalid record");
4617       unsigned NumDests = Record.size()-2;
4618       IndirectBrInst *IBI = IndirectBrInst::Create(Address, NumDests);
4619       InstructionList.push_back(IBI);
4620       for (unsigned i = 0, e = NumDests; i != e; ++i) {
4621         if (BasicBlock *DestBB = getBasicBlock(Record[2+i])) {
4622           IBI->addDestination(DestBB);
4623         } else {
4624           delete IBI;
4625           return error("Invalid record");
4626         }
4627       }
4628       I = IBI;
4629       break;
4630     }
4631 
4632     case bitc::FUNC_CODE_INST_INVOKE: {
4633       // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
4634       if (Record.size() < 4)
4635         return error("Invalid record");
4636       unsigned OpNum = 0;
4637       AttributeList PAL = getAttributes(Record[OpNum++]);
4638       unsigned CCInfo = Record[OpNum++];
4639       BasicBlock *NormalBB = getBasicBlock(Record[OpNum++]);
4640       BasicBlock *UnwindBB = getBasicBlock(Record[OpNum++]);
4641 
4642       FunctionType *FTy = nullptr;
4643       if ((CCInfo >> 13) & 1) {
4644         FTy = dyn_cast<FunctionType>(getTypeByID(Record[OpNum++]));
4645         if (!FTy)
4646           return error("Explicit invoke type is not a function type");
4647       }
4648 
4649       Value *Callee;
4650       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
4651         return error("Invalid record");
4652 
4653       PointerType *CalleeTy = dyn_cast<PointerType>(Callee->getType());
4654       if (!CalleeTy)
4655         return error("Callee is not a pointer");
4656       if (!FTy) {
4657         FTy = dyn_cast<FunctionType>(
4658             cast<PointerType>(Callee->getType())->getElementType());
4659         if (!FTy)
4660           return error("Callee is not of pointer to function type");
4661       } else if (!CalleeTy->isOpaqueOrPointeeTypeMatches(FTy))
4662         return error("Explicit invoke type does not match pointee type of "
4663                      "callee operand");
4664       if (Record.size() < FTy->getNumParams() + OpNum)
4665         return error("Insufficient operands to call");
4666 
4667       SmallVector<Value*, 16> Ops;
4668       SmallVector<Type *, 16> ArgsTys;
4669       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
4670         Ops.push_back(getValue(Record, OpNum, NextValueNo,
4671                                FTy->getParamType(i)));
4672         ArgsTys.push_back(FTy->getParamType(i));
4673         if (!Ops.back())
4674           return error("Invalid record");
4675       }
4676 
4677       if (!FTy->isVarArg()) {
4678         if (Record.size() != OpNum)
4679           return error("Invalid record");
4680       } else {
4681         // Read type/value pairs for varargs params.
4682         while (OpNum != Record.size()) {
4683           Value *Op;
4684           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
4685             return error("Invalid record");
4686           Ops.push_back(Op);
4687           ArgsTys.push_back(Op->getType());
4688         }
4689       }
4690 
4691       I = InvokeInst::Create(FTy, Callee, NormalBB, UnwindBB, Ops,
4692                              OperandBundles);
4693       OperandBundles.clear();
4694       InstructionList.push_back(I);
4695       cast<InvokeInst>(I)->setCallingConv(
4696           static_cast<CallingConv::ID>(CallingConv::MaxID & CCInfo));
4697       cast<InvokeInst>(I)->setAttributes(PAL);
4698       propagateAttributeTypes(cast<CallBase>(I), ArgsTys);
4699 
4700       break;
4701     }
4702     case bitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
4703       unsigned Idx = 0;
4704       Value *Val = nullptr;
4705       if (getValueTypePair(Record, Idx, NextValueNo, Val))
4706         return error("Invalid record");
4707       I = ResumeInst::Create(Val);
4708       InstructionList.push_back(I);
4709       break;
4710     }
4711     case bitc::FUNC_CODE_INST_CALLBR: {
4712       // CALLBR: [attr, cc, norm, transfs, fty, fnid, args]
4713       unsigned OpNum = 0;
4714       AttributeList PAL = getAttributes(Record[OpNum++]);
4715       unsigned CCInfo = Record[OpNum++];
4716 
4717       BasicBlock *DefaultDest = getBasicBlock(Record[OpNum++]);
4718       unsigned NumIndirectDests = Record[OpNum++];
4719       SmallVector<BasicBlock *, 16> IndirectDests;
4720       for (unsigned i = 0, e = NumIndirectDests; i != e; ++i)
4721         IndirectDests.push_back(getBasicBlock(Record[OpNum++]));
4722 
4723       FunctionType *FTy = nullptr;
4724       if ((CCInfo >> bitc::CALL_EXPLICIT_TYPE) & 1) {
4725         FTy = dyn_cast<FunctionType>(getTypeByID(Record[OpNum++]));
4726         if (!FTy)
4727           return error("Explicit call type is not a function type");
4728       }
4729 
4730       Value *Callee;
4731       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
4732         return error("Invalid record");
4733 
4734       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
4735       if (!OpTy)
4736         return error("Callee is not a pointer type");
4737       if (!FTy) {
4738         FTy = dyn_cast<FunctionType>(
4739             cast<PointerType>(Callee->getType())->getElementType());
4740         if (!FTy)
4741           return error("Callee is not of pointer to function type");
4742       } else if (cast<PointerType>(Callee->getType())->getElementType() != FTy)
4743         return error("Explicit call type does not match pointee type of "
4744                      "callee operand");
4745       if (Record.size() < FTy->getNumParams() + OpNum)
4746         return error("Insufficient operands to call");
4747 
4748       SmallVector<Value*, 16> Args;
4749       // Read the fixed params.
4750       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
4751         if (FTy->getParamType(i)->isLabelTy())
4752           Args.push_back(getBasicBlock(Record[OpNum]));
4753         else
4754           Args.push_back(getValue(Record, OpNum, NextValueNo,
4755                                   FTy->getParamType(i)));
4756         if (!Args.back())
4757           return error("Invalid record");
4758       }
4759 
4760       // Read type/value pairs for varargs params.
4761       if (!FTy->isVarArg()) {
4762         if (OpNum != Record.size())
4763           return error("Invalid record");
4764       } else {
4765         while (OpNum != Record.size()) {
4766           Value *Op;
4767           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
4768             return error("Invalid record");
4769           Args.push_back(Op);
4770         }
4771       }
4772 
4773       I = CallBrInst::Create(FTy, Callee, DefaultDest, IndirectDests, Args,
4774                              OperandBundles);
4775       OperandBundles.clear();
4776       InstructionList.push_back(I);
4777       cast<CallBrInst>(I)->setCallingConv(
4778           static_cast<CallingConv::ID>((0x7ff & CCInfo) >> bitc::CALL_CCONV));
4779       cast<CallBrInst>(I)->setAttributes(PAL);
4780       break;
4781     }
4782     case bitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
4783       I = new UnreachableInst(Context);
4784       InstructionList.push_back(I);
4785       break;
4786     case bitc::FUNC_CODE_INST_PHI: { // PHI: [ty, val0,bb0, ...]
4787       if (Record.empty())
4788         return error("Invalid record");
4789       // The first record specifies the type.
4790       Type *Ty = getTypeByID(Record[0]);
4791       if (!Ty)
4792         return error("Invalid record");
4793 
4794       // Phi arguments are pairs of records of [value, basic block].
4795       // There is an optional final record for fast-math-flags if this phi has a
4796       // floating-point type.
4797       size_t NumArgs = (Record.size() - 1) / 2;
4798       PHINode *PN = PHINode::Create(Ty, NumArgs);
4799       if ((Record.size() - 1) % 2 == 1 && !isa<FPMathOperator>(PN))
4800         return error("Invalid record");
4801       InstructionList.push_back(PN);
4802 
4803       for (unsigned i = 0; i != NumArgs; i++) {
4804         Value *V;
4805         // With the new function encoding, it is possible that operands have
4806         // negative IDs (for forward references).  Use a signed VBR
4807         // representation to keep the encoding small.
4808         if (UseRelativeIDs)
4809           V = getValueSigned(Record, i * 2 + 1, NextValueNo, Ty);
4810         else
4811           V = getValue(Record, i * 2 + 1, NextValueNo, Ty);
4812         BasicBlock *BB = getBasicBlock(Record[i * 2 + 2]);
4813         if (!V || !BB)
4814           return error("Invalid record");
4815         PN->addIncoming(V, BB);
4816       }
4817       I = PN;
4818 
4819       // If there are an even number of records, the final record must be FMF.
4820       if (Record.size() % 2 == 0) {
4821         assert(isa<FPMathOperator>(I) && "Unexpected phi type");
4822         FastMathFlags FMF = getDecodedFastMathFlags(Record[Record.size() - 1]);
4823         if (FMF.any())
4824           I->setFastMathFlags(FMF);
4825       }
4826 
4827       break;
4828     }
4829 
4830     case bitc::FUNC_CODE_INST_LANDINGPAD:
4831     case bitc::FUNC_CODE_INST_LANDINGPAD_OLD: {
4832       // LANDINGPAD: [ty, val, val, num, (id0,val0 ...)?]
4833       unsigned Idx = 0;
4834       if (BitCode == bitc::FUNC_CODE_INST_LANDINGPAD) {
4835         if (Record.size() < 3)
4836           return error("Invalid record");
4837       } else {
4838         assert(BitCode == bitc::FUNC_CODE_INST_LANDINGPAD_OLD);
4839         if (Record.size() < 4)
4840           return error("Invalid record");
4841       }
4842       Type *Ty = getTypeByID(Record[Idx++]);
4843       if (!Ty)
4844         return error("Invalid record");
4845       if (BitCode == bitc::FUNC_CODE_INST_LANDINGPAD_OLD) {
4846         Value *PersFn = nullptr;
4847         if (getValueTypePair(Record, Idx, NextValueNo, PersFn))
4848           return error("Invalid record");
4849 
4850         if (!F->hasPersonalityFn())
4851           F->setPersonalityFn(cast<Constant>(PersFn));
4852         else if (F->getPersonalityFn() != cast<Constant>(PersFn))
4853           return error("Personality function mismatch");
4854       }
4855 
4856       bool IsCleanup = !!Record[Idx++];
4857       unsigned NumClauses = Record[Idx++];
4858       LandingPadInst *LP = LandingPadInst::Create(Ty, NumClauses);
4859       LP->setCleanup(IsCleanup);
4860       for (unsigned J = 0; J != NumClauses; ++J) {
4861         LandingPadInst::ClauseType CT =
4862           LandingPadInst::ClauseType(Record[Idx++]); (void)CT;
4863         Value *Val;
4864 
4865         if (getValueTypePair(Record, Idx, NextValueNo, Val)) {
4866           delete LP;
4867           return error("Invalid record");
4868         }
4869 
4870         assert((CT != LandingPadInst::Catch ||
4871                 !isa<ArrayType>(Val->getType())) &&
4872                "Catch clause has a invalid type!");
4873         assert((CT != LandingPadInst::Filter ||
4874                 isa<ArrayType>(Val->getType())) &&
4875                "Filter clause has invalid type!");
4876         LP->addClause(cast<Constant>(Val));
4877       }
4878 
4879       I = LP;
4880       InstructionList.push_back(I);
4881       break;
4882     }
4883 
4884     case bitc::FUNC_CODE_INST_ALLOCA: { // ALLOCA: [instty, opty, op, align]
4885       if (Record.size() != 4)
4886         return error("Invalid record");
4887       using APV = AllocaPackedValues;
4888       const uint64_t Rec = Record[3];
4889       const bool InAlloca = Bitfield::get<APV::UsedWithInAlloca>(Rec);
4890       const bool SwiftError = Bitfield::get<APV::SwiftError>(Rec);
4891       Type *Ty = getTypeByID(Record[0]);
4892       if (!Bitfield::get<APV::ExplicitType>(Rec)) {
4893         auto *PTy = dyn_cast_or_null<PointerType>(Ty);
4894         if (!PTy)
4895           return error("Old-style alloca with a non-pointer type");
4896         Ty = PTy->getElementType();
4897       }
4898       Type *OpTy = getTypeByID(Record[1]);
4899       Value *Size = getFnValueByID(Record[2], OpTy);
4900       MaybeAlign Align;
4901       if (Error Err =
4902               parseAlignmentValue(Bitfield::get<APV::Align>(Rec), Align)) {
4903         return Err;
4904       }
4905       if (!Ty || !Size)
4906         return error("Invalid record");
4907 
4908       // FIXME: Make this an optional field.
4909       const DataLayout &DL = TheModule->getDataLayout();
4910       unsigned AS = DL.getAllocaAddrSpace();
4911 
4912       SmallPtrSet<Type *, 4> Visited;
4913       if (!Align && !Ty->isSized(&Visited))
4914         return error("alloca of unsized type");
4915       if (!Align)
4916         Align = DL.getPrefTypeAlign(Ty);
4917 
4918       AllocaInst *AI = new AllocaInst(Ty, AS, Size, *Align);
4919       AI->setUsedWithInAlloca(InAlloca);
4920       AI->setSwiftError(SwiftError);
4921       I = AI;
4922       InstructionList.push_back(I);
4923       break;
4924     }
4925     case bitc::FUNC_CODE_INST_LOAD: { // LOAD: [opty, op, align, vol]
4926       unsigned OpNum = 0;
4927       Value *Op;
4928       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
4929           (OpNum + 2 != Record.size() && OpNum + 3 != Record.size()))
4930         return error("Invalid record");
4931 
4932       if (!isa<PointerType>(Op->getType()))
4933         return error("Load operand is not a pointer type");
4934 
4935       Type *Ty = nullptr;
4936       if (OpNum + 3 == Record.size()) {
4937         Ty = getTypeByID(Record[OpNum++]);
4938       } else {
4939         Ty = cast<PointerType>(Op->getType())->getElementType();
4940       }
4941 
4942       if (Error Err = typeCheckLoadStoreInst(Ty, Op->getType()))
4943         return Err;
4944 
4945       MaybeAlign Align;
4946       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
4947         return Err;
4948       SmallPtrSet<Type *, 4> Visited;
4949       if (!Align && !Ty->isSized(&Visited))
4950         return error("load of unsized type");
4951       if (!Align)
4952         Align = TheModule->getDataLayout().getABITypeAlign(Ty);
4953       I = new LoadInst(Ty, Op, "", Record[OpNum + 1], *Align);
4954       InstructionList.push_back(I);
4955       break;
4956     }
4957     case bitc::FUNC_CODE_INST_LOADATOMIC: {
4958        // LOADATOMIC: [opty, op, align, vol, ordering, ssid]
4959       unsigned OpNum = 0;
4960       Value *Op;
4961       if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
4962           (OpNum + 4 != Record.size() && OpNum + 5 != Record.size()))
4963         return error("Invalid record");
4964 
4965       if (!isa<PointerType>(Op->getType()))
4966         return error("Load operand is not a pointer type");
4967 
4968       Type *Ty = nullptr;
4969       if (OpNum + 5 == Record.size()) {
4970         Ty = getTypeByID(Record[OpNum++]);
4971       } else {
4972         Ty = cast<PointerType>(Op->getType())->getElementType();
4973       }
4974 
4975       if (Error Err = typeCheckLoadStoreInst(Ty, Op->getType()))
4976         return Err;
4977 
4978       AtomicOrdering Ordering = getDecodedOrdering(Record[OpNum + 2]);
4979       if (Ordering == AtomicOrdering::NotAtomic ||
4980           Ordering == AtomicOrdering::Release ||
4981           Ordering == AtomicOrdering::AcquireRelease)
4982         return error("Invalid record");
4983       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
4984         return error("Invalid record");
4985       SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
4986 
4987       MaybeAlign Align;
4988       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
4989         return Err;
4990       if (!Align)
4991         return error("Alignment missing from atomic load");
4992       I = new LoadInst(Ty, Op, "", Record[OpNum + 1], *Align, Ordering, SSID);
4993       InstructionList.push_back(I);
4994       break;
4995     }
4996     case bitc::FUNC_CODE_INST_STORE:
4997     case bitc::FUNC_CODE_INST_STORE_OLD: { // STORE2:[ptrty, ptr, val, align, vol]
4998       unsigned OpNum = 0;
4999       Value *Val, *Ptr;
5000       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
5001           (BitCode == bitc::FUNC_CODE_INST_STORE
5002                ? getValueTypePair(Record, OpNum, NextValueNo, Val)
5003                : popValue(Record, OpNum, NextValueNo,
5004                           cast<PointerType>(Ptr->getType())->getElementType(),
5005                           Val)) ||
5006           OpNum + 2 != Record.size())
5007         return error("Invalid record");
5008 
5009       if (Error Err = typeCheckLoadStoreInst(Val->getType(), Ptr->getType()))
5010         return Err;
5011       MaybeAlign Align;
5012       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
5013         return Err;
5014       SmallPtrSet<Type *, 4> Visited;
5015       if (!Align && !Val->getType()->isSized(&Visited))
5016         return error("store of unsized type");
5017       if (!Align)
5018         Align = TheModule->getDataLayout().getABITypeAlign(Val->getType());
5019       I = new StoreInst(Val, Ptr, Record[OpNum + 1], *Align);
5020       InstructionList.push_back(I);
5021       break;
5022     }
5023     case bitc::FUNC_CODE_INST_STOREATOMIC:
5024     case bitc::FUNC_CODE_INST_STOREATOMIC_OLD: {
5025       // STOREATOMIC: [ptrty, ptr, val, align, vol, ordering, ssid]
5026       unsigned OpNum = 0;
5027       Value *Val, *Ptr;
5028       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) ||
5029           !isa<PointerType>(Ptr->getType()) ||
5030           (BitCode == bitc::FUNC_CODE_INST_STOREATOMIC
5031                ? getValueTypePair(Record, OpNum, NextValueNo, Val)
5032                : popValue(Record, OpNum, NextValueNo,
5033                           cast<PointerType>(Ptr->getType())->getElementType(),
5034                           Val)) ||
5035           OpNum + 4 != Record.size())
5036         return error("Invalid record");
5037 
5038       if (Error Err = typeCheckLoadStoreInst(Val->getType(), Ptr->getType()))
5039         return Err;
5040       AtomicOrdering Ordering = getDecodedOrdering(Record[OpNum + 2]);
5041       if (Ordering == AtomicOrdering::NotAtomic ||
5042           Ordering == AtomicOrdering::Acquire ||
5043           Ordering == AtomicOrdering::AcquireRelease)
5044         return error("Invalid record");
5045       SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
5046       if (Ordering != AtomicOrdering::NotAtomic && Record[OpNum] == 0)
5047         return error("Invalid record");
5048 
5049       MaybeAlign Align;
5050       if (Error Err = parseAlignmentValue(Record[OpNum], Align))
5051         return Err;
5052       if (!Align)
5053         return error("Alignment missing from atomic store");
5054       I = new StoreInst(Val, Ptr, Record[OpNum + 1], *Align, Ordering, SSID);
5055       InstructionList.push_back(I);
5056       break;
5057     }
5058     case bitc::FUNC_CODE_INST_CMPXCHG_OLD: {
5059       // CMPXCHG_OLD: [ptrty, ptr, cmp, val, vol, ordering, synchscope,
5060       // failure_ordering?, weak?]
5061       const size_t NumRecords = Record.size();
5062       unsigned OpNum = 0;
5063       Value *Ptr = nullptr;
5064       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr))
5065         return error("Invalid record");
5066 
5067       if (!isa<PointerType>(Ptr->getType()))
5068         return error("Cmpxchg operand is not a pointer type");
5069 
5070       Value *Cmp = nullptr;
5071       if (popValue(Record, OpNum, NextValueNo,
5072                    cast<PointerType>(Ptr->getType())->getPointerElementType(),
5073                    Cmp))
5074         return error("Invalid record");
5075 
5076       Value *New = nullptr;
5077       if (popValue(Record, OpNum, NextValueNo, Cmp->getType(), New) ||
5078           NumRecords < OpNum + 3 || NumRecords > OpNum + 5)
5079         return error("Invalid record");
5080 
5081       const AtomicOrdering SuccessOrdering =
5082           getDecodedOrdering(Record[OpNum + 1]);
5083       if (SuccessOrdering == AtomicOrdering::NotAtomic ||
5084           SuccessOrdering == AtomicOrdering::Unordered)
5085         return error("Invalid record");
5086 
5087       const SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 2]);
5088 
5089       if (Error Err = typeCheckLoadStoreInst(Cmp->getType(), Ptr->getType()))
5090         return Err;
5091 
5092       const AtomicOrdering FailureOrdering =
5093           NumRecords < 7
5094               ? AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrdering)
5095               : getDecodedOrdering(Record[OpNum + 3]);
5096 
5097       if (FailureOrdering == AtomicOrdering::NotAtomic ||
5098           FailureOrdering == AtomicOrdering::Unordered)
5099         return error("Invalid record");
5100 
5101       const Align Alignment(
5102           TheModule->getDataLayout().getTypeStoreSize(Cmp->getType()));
5103 
5104       I = new AtomicCmpXchgInst(Ptr, Cmp, New, Alignment, SuccessOrdering,
5105                                 FailureOrdering, SSID);
5106       cast<AtomicCmpXchgInst>(I)->setVolatile(Record[OpNum]);
5107 
5108       if (NumRecords < 8) {
5109         // Before weak cmpxchgs existed, the instruction simply returned the
5110         // value loaded from memory, so bitcode files from that era will be
5111         // expecting the first component of a modern cmpxchg.
5112         CurBB->getInstList().push_back(I);
5113         I = ExtractValueInst::Create(I, 0);
5114       } else {
5115         cast<AtomicCmpXchgInst>(I)->setWeak(Record[OpNum + 4]);
5116       }
5117 
5118       InstructionList.push_back(I);
5119       break;
5120     }
5121     case bitc::FUNC_CODE_INST_CMPXCHG: {
5122       // CMPXCHG: [ptrty, ptr, cmp, val, vol, success_ordering, synchscope,
5123       // failure_ordering, weak, align?]
5124       const size_t NumRecords = Record.size();
5125       unsigned OpNum = 0;
5126       Value *Ptr = nullptr;
5127       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr))
5128         return error("Invalid record");
5129 
5130       if (!isa<PointerType>(Ptr->getType()))
5131         return error("Cmpxchg operand is not a pointer type");
5132 
5133       Value *Cmp = nullptr;
5134       if (getValueTypePair(Record, OpNum, NextValueNo, Cmp))
5135         return error("Invalid record");
5136 
5137       Value *Val = nullptr;
5138       if (popValue(Record, OpNum, NextValueNo, Cmp->getType(), Val))
5139         return error("Invalid record");
5140 
5141       if (NumRecords < OpNum + 3 || NumRecords > OpNum + 6)
5142         return error("Invalid record");
5143 
5144       const bool IsVol = Record[OpNum];
5145 
5146       const AtomicOrdering SuccessOrdering =
5147           getDecodedOrdering(Record[OpNum + 1]);
5148       if (!AtomicCmpXchgInst::isValidSuccessOrdering(SuccessOrdering))
5149         return error("Invalid cmpxchg success ordering");
5150 
5151       const SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 2]);
5152 
5153       if (Error Err = typeCheckLoadStoreInst(Cmp->getType(), Ptr->getType()))
5154         return Err;
5155 
5156       const AtomicOrdering FailureOrdering =
5157           getDecodedOrdering(Record[OpNum + 3]);
5158       if (!AtomicCmpXchgInst::isValidFailureOrdering(FailureOrdering))
5159         return error("Invalid cmpxchg failure ordering");
5160 
5161       const bool IsWeak = Record[OpNum + 4];
5162 
5163       MaybeAlign Alignment;
5164 
5165       if (NumRecords == (OpNum + 6)) {
5166         if (Error Err = parseAlignmentValue(Record[OpNum + 5], Alignment))
5167           return Err;
5168       }
5169       if (!Alignment)
5170         Alignment =
5171             Align(TheModule->getDataLayout().getTypeStoreSize(Cmp->getType()));
5172 
5173       I = new AtomicCmpXchgInst(Ptr, Cmp, Val, *Alignment, SuccessOrdering,
5174                                 FailureOrdering, SSID);
5175       cast<AtomicCmpXchgInst>(I)->setVolatile(IsVol);
5176       cast<AtomicCmpXchgInst>(I)->setWeak(IsWeak);
5177 
5178       InstructionList.push_back(I);
5179       break;
5180     }
5181     case bitc::FUNC_CODE_INST_ATOMICRMW_OLD:
5182     case bitc::FUNC_CODE_INST_ATOMICRMW: {
5183       // ATOMICRMW_OLD: [ptrty, ptr, val, op, vol, ordering, ssid, align?]
5184       // ATOMICRMW: [ptrty, ptr, valty, val, op, vol, ordering, ssid, align?]
5185       const size_t NumRecords = Record.size();
5186       unsigned OpNum = 0;
5187 
5188       Value *Ptr = nullptr;
5189       if (getValueTypePair(Record, OpNum, NextValueNo, Ptr))
5190         return error("Invalid record");
5191 
5192       if (!isa<PointerType>(Ptr->getType()))
5193         return error("Invalid record");
5194 
5195       Value *Val = nullptr;
5196       if (BitCode == bitc::FUNC_CODE_INST_ATOMICRMW_OLD) {
5197         if (popValue(Record, OpNum, NextValueNo,
5198                      cast<PointerType>(Ptr->getType())->getPointerElementType(),
5199                      Val))
5200           return error("Invalid record");
5201       } else {
5202         if (getValueTypePair(Record, OpNum, NextValueNo, Val))
5203           return error("Invalid record");
5204       }
5205 
5206       if (!(NumRecords == (OpNum + 4) || NumRecords == (OpNum + 5)))
5207         return error("Invalid record");
5208 
5209       const AtomicRMWInst::BinOp Operation =
5210           getDecodedRMWOperation(Record[OpNum]);
5211       if (Operation < AtomicRMWInst::FIRST_BINOP ||
5212           Operation > AtomicRMWInst::LAST_BINOP)
5213         return error("Invalid record");
5214 
5215       const bool IsVol = Record[OpNum + 1];
5216 
5217       const AtomicOrdering Ordering = getDecodedOrdering(Record[OpNum + 2]);
5218       if (Ordering == AtomicOrdering::NotAtomic ||
5219           Ordering == AtomicOrdering::Unordered)
5220         return error("Invalid record");
5221 
5222       const SyncScope::ID SSID = getDecodedSyncScopeID(Record[OpNum + 3]);
5223 
5224       MaybeAlign Alignment;
5225 
5226       if (NumRecords == (OpNum + 5)) {
5227         if (Error Err = parseAlignmentValue(Record[OpNum + 4], Alignment))
5228           return Err;
5229       }
5230 
5231       if (!Alignment)
5232         Alignment =
5233             Align(TheModule->getDataLayout().getTypeStoreSize(Val->getType()));
5234 
5235       I = new AtomicRMWInst(Operation, Ptr, Val, *Alignment, Ordering, SSID);
5236       cast<AtomicRMWInst>(I)->setVolatile(IsVol);
5237 
5238       InstructionList.push_back(I);
5239       break;
5240     }
5241     case bitc::FUNC_CODE_INST_FENCE: { // FENCE:[ordering, ssid]
5242       if (2 != Record.size())
5243         return error("Invalid record");
5244       AtomicOrdering Ordering = getDecodedOrdering(Record[0]);
5245       if (Ordering == AtomicOrdering::NotAtomic ||
5246           Ordering == AtomicOrdering::Unordered ||
5247           Ordering == AtomicOrdering::Monotonic)
5248         return error("Invalid record");
5249       SyncScope::ID SSID = getDecodedSyncScopeID(Record[1]);
5250       I = new FenceInst(Context, Ordering, SSID);
5251       InstructionList.push_back(I);
5252       break;
5253     }
5254     case bitc::FUNC_CODE_INST_CALL: {
5255       // CALL: [paramattrs, cc, fmf, fnty, fnid, arg0, arg1...]
5256       if (Record.size() < 3)
5257         return error("Invalid record");
5258 
5259       unsigned OpNum = 0;
5260       AttributeList PAL = getAttributes(Record[OpNum++]);
5261       unsigned CCInfo = Record[OpNum++];
5262 
5263       FastMathFlags FMF;
5264       if ((CCInfo >> bitc::CALL_FMF) & 1) {
5265         FMF = getDecodedFastMathFlags(Record[OpNum++]);
5266         if (!FMF.any())
5267           return error("Fast math flags indicator set for call with no FMF");
5268       }
5269 
5270       FunctionType *FTy = nullptr;
5271       if ((CCInfo >> bitc::CALL_EXPLICIT_TYPE) & 1) {
5272         FTy = dyn_cast<FunctionType>(getTypeByID(Record[OpNum++]));
5273         if (!FTy)
5274           return error("Explicit call type is not a function type");
5275       }
5276 
5277       Value *Callee;
5278       if (getValueTypePair(Record, OpNum, NextValueNo, Callee))
5279         return error("Invalid record");
5280 
5281       PointerType *OpTy = dyn_cast<PointerType>(Callee->getType());
5282       if (!OpTy)
5283         return error("Callee is not a pointer type");
5284       if (!FTy) {
5285         FTy = dyn_cast<FunctionType>(
5286             cast<PointerType>(Callee->getType())->getElementType());
5287         if (!FTy)
5288           return error("Callee is not of pointer to function type");
5289       } else if (!OpTy->isOpaqueOrPointeeTypeMatches(FTy))
5290         return error("Explicit call type does not match pointee type of "
5291                      "callee operand");
5292       if (Record.size() < FTy->getNumParams() + OpNum)
5293         return error("Insufficient operands to call");
5294 
5295       SmallVector<Value*, 16> Args;
5296       SmallVector<Type *, 16> ArgsTys;
5297       // Read the fixed params.
5298       for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i, ++OpNum) {
5299         if (FTy->getParamType(i)->isLabelTy())
5300           Args.push_back(getBasicBlock(Record[OpNum]));
5301         else
5302           Args.push_back(getValue(Record, OpNum, NextValueNo,
5303                                   FTy->getParamType(i)));
5304         ArgsTys.push_back(FTy->getParamType(i));
5305         if (!Args.back())
5306           return error("Invalid record");
5307       }
5308 
5309       // Read type/value pairs for varargs params.
5310       if (!FTy->isVarArg()) {
5311         if (OpNum != Record.size())
5312           return error("Invalid record");
5313       } else {
5314         while (OpNum != Record.size()) {
5315           Value *Op;
5316           if (getValueTypePair(Record, OpNum, NextValueNo, Op))
5317             return error("Invalid record");
5318           Args.push_back(Op);
5319           ArgsTys.push_back(Op->getType());
5320         }
5321       }
5322 
5323       I = CallInst::Create(FTy, Callee, Args, OperandBundles);
5324       OperandBundles.clear();
5325       InstructionList.push_back(I);
5326       cast<CallInst>(I)->setCallingConv(
5327           static_cast<CallingConv::ID>((0x7ff & CCInfo) >> bitc::CALL_CCONV));
5328       CallInst::TailCallKind TCK = CallInst::TCK_None;
5329       if (CCInfo & 1 << bitc::CALL_TAIL)
5330         TCK = CallInst::TCK_Tail;
5331       if (CCInfo & (1 << bitc::CALL_MUSTTAIL))
5332         TCK = CallInst::TCK_MustTail;
5333       if (CCInfo & (1 << bitc::CALL_NOTAIL))
5334         TCK = CallInst::TCK_NoTail;
5335       cast<CallInst>(I)->setTailCallKind(TCK);
5336       cast<CallInst>(I)->setAttributes(PAL);
5337       propagateAttributeTypes(cast<CallBase>(I), ArgsTys);
5338       if (FMF.any()) {
5339         if (!isa<FPMathOperator>(I))
5340           return error("Fast-math-flags specified for call without "
5341                        "floating-point scalar or vector return type");
5342         I->setFastMathFlags(FMF);
5343       }
5344       break;
5345     }
5346     case bitc::FUNC_CODE_INST_VAARG: { // VAARG: [valistty, valist, instty]
5347       if (Record.size() < 3)
5348         return error("Invalid record");
5349       Type *OpTy = getTypeByID(Record[0]);
5350       Value *Op = getValue(Record, 1, NextValueNo, OpTy);
5351       Type *ResTy = getTypeByID(Record[2]);
5352       if (!OpTy || !Op || !ResTy)
5353         return error("Invalid record");
5354       I = new VAArgInst(Op, ResTy);
5355       InstructionList.push_back(I);
5356       break;
5357     }
5358 
5359     case bitc::FUNC_CODE_OPERAND_BUNDLE: {
5360       // A call or an invoke can be optionally prefixed with some variable
5361       // number of operand bundle blocks.  These blocks are read into
5362       // OperandBundles and consumed at the next call or invoke instruction.
5363 
5364       if (Record.empty() || Record[0] >= BundleTags.size())
5365         return error("Invalid record");
5366 
5367       std::vector<Value *> Inputs;
5368 
5369       unsigned OpNum = 1;
5370       while (OpNum != Record.size()) {
5371         Value *Op;
5372         if (getValueTypePair(Record, OpNum, NextValueNo, Op))
5373           return error("Invalid record");
5374         Inputs.push_back(Op);
5375       }
5376 
5377       OperandBundles.emplace_back(BundleTags[Record[0]], std::move(Inputs));
5378       continue;
5379     }
5380 
5381     case bitc::FUNC_CODE_INST_FREEZE: { // FREEZE: [opty,opval]
5382       unsigned OpNum = 0;
5383       Value *Op = nullptr;
5384       if (getValueTypePair(Record, OpNum, NextValueNo, Op))
5385         return error("Invalid record");
5386       if (OpNum != Record.size())
5387         return error("Invalid record");
5388 
5389       I = new FreezeInst(Op);
5390       InstructionList.push_back(I);
5391       break;
5392     }
5393     }
5394 
5395     // Add instruction to end of current BB.  If there is no current BB, reject
5396     // this file.
5397     if (!CurBB) {
5398       I->deleteValue();
5399       return error("Invalid instruction with no BB");
5400     }
5401     if (!OperandBundles.empty()) {
5402       I->deleteValue();
5403       return error("Operand bundles found with no consumer");
5404     }
5405     CurBB->getInstList().push_back(I);
5406 
5407     // If this was a terminator instruction, move to the next block.
5408     if (I->isTerminator()) {
5409       ++CurBBNo;
5410       CurBB = CurBBNo < FunctionBBs.size() ? FunctionBBs[CurBBNo] : nullptr;
5411     }
5412 
5413     // Non-void values get registered in the value table for future use.
5414     if (!I->getType()->isVoidTy())
5415       ValueList.assignValue(I, NextValueNo++);
5416   }
5417 
5418 OutOfRecordLoop:
5419 
5420   if (!OperandBundles.empty())
5421     return error("Operand bundles found with no consumer");
5422 
5423   // Check the function list for unresolved values.
5424   if (Argument *A = dyn_cast<Argument>(ValueList.back())) {
5425     if (!A->getParent()) {
5426       // We found at least one unresolved value.  Nuke them all to avoid leaks.
5427       for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
5428         if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && !A->getParent()) {
5429           A->replaceAllUsesWith(UndefValue::get(A->getType()));
5430           delete A;
5431         }
5432       }
5433       return error("Never resolved value found in function");
5434     }
5435   }
5436 
5437   // Unexpected unresolved metadata about to be dropped.
5438   if (MDLoader->hasFwdRefs())
5439     return error("Invalid function metadata: outgoing forward refs");
5440 
5441   // Trim the value list down to the size it was before we parsed this function.
5442   ValueList.shrinkTo(ModuleValueListSize);
5443   MDLoader->shrinkTo(ModuleMDLoaderSize);
5444   std::vector<BasicBlock*>().swap(FunctionBBs);
5445   return Error::success();
5446 }
5447 
5448 /// Find the function body in the bitcode stream
5449 Error BitcodeReader::findFunctionInStream(
5450     Function *F,
5451     DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
5452   while (DeferredFunctionInfoIterator->second == 0) {
5453     // This is the fallback handling for the old format bitcode that
5454     // didn't contain the function index in the VST, or when we have
5455     // an anonymous function which would not have a VST entry.
5456     // Assert that we have one of those two cases.
5457     assert(VSTOffset == 0 || !F->hasName());
5458     // Parse the next body in the stream and set its position in the
5459     // DeferredFunctionInfo map.
5460     if (Error Err = rememberAndSkipFunctionBodies())
5461       return Err;
5462   }
5463   return Error::success();
5464 }
5465 
5466 SyncScope::ID BitcodeReader::getDecodedSyncScopeID(unsigned Val) {
5467   if (Val == SyncScope::SingleThread || Val == SyncScope::System)
5468     return SyncScope::ID(Val);
5469   if (Val >= SSIDs.size())
5470     return SyncScope::System; // Map unknown synchronization scopes to system.
5471   return SSIDs[Val];
5472 }
5473 
5474 //===----------------------------------------------------------------------===//
5475 // GVMaterializer implementation
5476 //===----------------------------------------------------------------------===//
5477 
5478 Error BitcodeReader::materialize(GlobalValue *GV) {
5479   Function *F = dyn_cast<Function>(GV);
5480   // If it's not a function or is already material, ignore the request.
5481   if (!F || !F->isMaterializable())
5482     return Error::success();
5483 
5484   DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
5485   assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
5486   // If its position is recorded as 0, its body is somewhere in the stream
5487   // but we haven't seen it yet.
5488   if (DFII->second == 0)
5489     if (Error Err = findFunctionInStream(F, DFII))
5490       return Err;
5491 
5492   // Materialize metadata before parsing any function bodies.
5493   if (Error Err = materializeMetadata())
5494     return Err;
5495 
5496   // Move the bit stream to the saved position of the deferred function body.
5497   if (Error JumpFailed = Stream.JumpToBit(DFII->second))
5498     return JumpFailed;
5499   if (Error Err = parseFunctionBody(F))
5500     return Err;
5501   F->setIsMaterializable(false);
5502 
5503   if (StripDebugInfo)
5504     stripDebugInfo(*F);
5505 
5506   // Upgrade any old intrinsic calls in the function.
5507   for (auto &I : UpgradedIntrinsics) {
5508     for (auto UI = I.first->materialized_user_begin(), UE = I.first->user_end();
5509          UI != UE;) {
5510       User *U = *UI;
5511       ++UI;
5512       if (CallInst *CI = dyn_cast<CallInst>(U))
5513         UpgradeIntrinsicCall(CI, I.second);
5514     }
5515   }
5516 
5517   // Update calls to the remangled intrinsics
5518   for (auto &I : RemangledIntrinsics)
5519     for (auto UI = I.first->materialized_user_begin(), UE = I.first->user_end();
5520          UI != UE;)
5521       // Don't expect any other users than call sites
5522       cast<CallBase>(*UI++)->setCalledFunction(I.second);
5523 
5524   // Finish fn->subprogram upgrade for materialized functions.
5525   if (DISubprogram *SP = MDLoader->lookupSubprogramForFunction(F))
5526     F->setSubprogram(SP);
5527 
5528   // Check if the TBAA Metadata are valid, otherwise we will need to strip them.
5529   if (!MDLoader->isStrippingTBAA()) {
5530     for (auto &I : instructions(F)) {
5531       MDNode *TBAA = I.getMetadata(LLVMContext::MD_tbaa);
5532       if (!TBAA || TBAAVerifyHelper.visitTBAAMetadata(I, TBAA))
5533         continue;
5534       MDLoader->setStripTBAA(true);
5535       stripTBAA(F->getParent());
5536     }
5537   }
5538 
5539   for (auto &I : instructions(F)) {
5540     // "Upgrade" older incorrect branch weights by dropping them.
5541     if (auto *MD = I.getMetadata(LLVMContext::MD_prof)) {
5542       if (MD->getOperand(0) != nullptr && isa<MDString>(MD->getOperand(0))) {
5543         MDString *MDS = cast<MDString>(MD->getOperand(0));
5544         StringRef ProfName = MDS->getString();
5545         // Check consistency of !prof branch_weights metadata.
5546         if (!ProfName.equals("branch_weights"))
5547           continue;
5548         unsigned ExpectedNumOperands = 0;
5549         if (BranchInst *BI = dyn_cast<BranchInst>(&I))
5550           ExpectedNumOperands = BI->getNumSuccessors();
5551         else if (SwitchInst *SI = dyn_cast<SwitchInst>(&I))
5552           ExpectedNumOperands = SI->getNumSuccessors();
5553         else if (isa<CallInst>(&I))
5554           ExpectedNumOperands = 1;
5555         else if (IndirectBrInst *IBI = dyn_cast<IndirectBrInst>(&I))
5556           ExpectedNumOperands = IBI->getNumDestinations();
5557         else if (isa<SelectInst>(&I))
5558           ExpectedNumOperands = 2;
5559         else
5560           continue; // ignore and continue.
5561 
5562         // If branch weight doesn't match, just strip branch weight.
5563         if (MD->getNumOperands() != 1 + ExpectedNumOperands)
5564           I.setMetadata(LLVMContext::MD_prof, nullptr);
5565       }
5566     }
5567 
5568     // Remove incompatible attributes on function calls.
5569     if (auto *CI = dyn_cast<CallBase>(&I)) {
5570       CI->removeAttributes(AttributeList::ReturnIndex,
5571                            AttributeFuncs::typeIncompatible(
5572                                CI->getFunctionType()->getReturnType()));
5573 
5574       for (unsigned ArgNo = 0; ArgNo < CI->arg_size(); ++ArgNo)
5575         CI->removeParamAttrs(ArgNo, AttributeFuncs::typeIncompatible(
5576                                         CI->getArgOperand(ArgNo)->getType()));
5577     }
5578   }
5579 
5580   // Look for functions that rely on old function attribute behavior.
5581   UpgradeFunctionAttributes(*F);
5582 
5583   // Bring in any functions that this function forward-referenced via
5584   // blockaddresses.
5585   return materializeForwardReferencedFunctions();
5586 }
5587 
5588 Error BitcodeReader::materializeModule() {
5589   if (Error Err = materializeMetadata())
5590     return Err;
5591 
5592   // Promise to materialize all forward references.
5593   WillMaterializeAllForwardRefs = true;
5594 
5595   // Iterate over the module, deserializing any functions that are still on
5596   // disk.
5597   for (Function &F : *TheModule) {
5598     if (Error Err = materialize(&F))
5599       return Err;
5600   }
5601   // At this point, if there are any function bodies, parse the rest of
5602   // the bits in the module past the last function block we have recorded
5603   // through either lazy scanning or the VST.
5604   if (LastFunctionBlockBit || NextUnreadBit)
5605     if (Error Err = parseModule(LastFunctionBlockBit > NextUnreadBit
5606                                     ? LastFunctionBlockBit
5607                                     : NextUnreadBit))
5608       return Err;
5609 
5610   // Check that all block address forward references got resolved (as we
5611   // promised above).
5612   if (!BasicBlockFwdRefs.empty())
5613     return error("Never resolved function from blockaddress");
5614 
5615   // Upgrade any intrinsic calls that slipped through (should not happen!) and
5616   // delete the old functions to clean up. We can't do this unless the entire
5617   // module is materialized because there could always be another function body
5618   // with calls to the old function.
5619   for (auto &I : UpgradedIntrinsics) {
5620     for (auto *U : I.first->users()) {
5621       if (CallInst *CI = dyn_cast<CallInst>(U))
5622         UpgradeIntrinsicCall(CI, I.second);
5623     }
5624     if (!I.first->use_empty())
5625       I.first->replaceAllUsesWith(I.second);
5626     I.first->eraseFromParent();
5627   }
5628   UpgradedIntrinsics.clear();
5629   // Do the same for remangled intrinsics
5630   for (auto &I : RemangledIntrinsics) {
5631     I.first->replaceAllUsesWith(I.second);
5632     I.first->eraseFromParent();
5633   }
5634   RemangledIntrinsics.clear();
5635 
5636   UpgradeDebugInfo(*TheModule);
5637 
5638   UpgradeModuleFlags(*TheModule);
5639 
5640   UpgradeARCRuntime(*TheModule);
5641 
5642   return Error::success();
5643 }
5644 
5645 std::vector<StructType *> BitcodeReader::getIdentifiedStructTypes() const {
5646   return IdentifiedStructTypes;
5647 }
5648 
5649 ModuleSummaryIndexBitcodeReader::ModuleSummaryIndexBitcodeReader(
5650     BitstreamCursor Cursor, StringRef Strtab, ModuleSummaryIndex &TheIndex,
5651     StringRef ModulePath, unsigned ModuleId)
5652     : BitcodeReaderBase(std::move(Cursor), Strtab), TheIndex(TheIndex),
5653       ModulePath(ModulePath), ModuleId(ModuleId) {}
5654 
5655 void ModuleSummaryIndexBitcodeReader::addThisModule() {
5656   TheIndex.addModule(ModulePath, ModuleId);
5657 }
5658 
5659 ModuleSummaryIndex::ModuleInfo *
5660 ModuleSummaryIndexBitcodeReader::getThisModule() {
5661   return TheIndex.getModule(ModulePath);
5662 }
5663 
5664 std::pair<ValueInfo, GlobalValue::GUID>
5665 ModuleSummaryIndexBitcodeReader::getValueInfoFromValueId(unsigned ValueId) {
5666   auto VGI = ValueIdToValueInfoMap[ValueId];
5667   assert(VGI.first);
5668   return VGI;
5669 }
5670 
5671 void ModuleSummaryIndexBitcodeReader::setValueGUID(
5672     uint64_t ValueID, StringRef ValueName, GlobalValue::LinkageTypes Linkage,
5673     StringRef SourceFileName) {
5674   std::string GlobalId =
5675       GlobalValue::getGlobalIdentifier(ValueName, Linkage, SourceFileName);
5676   auto ValueGUID = GlobalValue::getGUID(GlobalId);
5677   auto OriginalNameID = ValueGUID;
5678   if (GlobalValue::isLocalLinkage(Linkage))
5679     OriginalNameID = GlobalValue::getGUID(ValueName);
5680   if (PrintSummaryGUIDs)
5681     dbgs() << "GUID " << ValueGUID << "(" << OriginalNameID << ") is "
5682            << ValueName << "\n";
5683 
5684   // UseStrtab is false for legacy summary formats and value names are
5685   // created on stack. In that case we save the name in a string saver in
5686   // the index so that the value name can be recorded.
5687   ValueIdToValueInfoMap[ValueID] = std::make_pair(
5688       TheIndex.getOrInsertValueInfo(
5689           ValueGUID,
5690           UseStrtab ? ValueName : TheIndex.saveString(ValueName)),
5691       OriginalNameID);
5692 }
5693 
5694 // Specialized value symbol table parser used when reading module index
5695 // blocks where we don't actually create global values. The parsed information
5696 // is saved in the bitcode reader for use when later parsing summaries.
5697 Error ModuleSummaryIndexBitcodeReader::parseValueSymbolTable(
5698     uint64_t Offset,
5699     DenseMap<unsigned, GlobalValue::LinkageTypes> &ValueIdToLinkageMap) {
5700   // With a strtab the VST is not required to parse the summary.
5701   if (UseStrtab)
5702     return Error::success();
5703 
5704   assert(Offset > 0 && "Expected non-zero VST offset");
5705   Expected<uint64_t> MaybeCurrentBit = jumpToValueSymbolTable(Offset, Stream);
5706   if (!MaybeCurrentBit)
5707     return MaybeCurrentBit.takeError();
5708   uint64_t CurrentBit = MaybeCurrentBit.get();
5709 
5710   if (Error Err = Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
5711     return Err;
5712 
5713   SmallVector<uint64_t, 64> Record;
5714 
5715   // Read all the records for this value table.
5716   SmallString<128> ValueName;
5717 
5718   while (true) {
5719     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
5720     if (!MaybeEntry)
5721       return MaybeEntry.takeError();
5722     BitstreamEntry Entry = MaybeEntry.get();
5723 
5724     switch (Entry.Kind) {
5725     case BitstreamEntry::SubBlock: // Handled for us already.
5726     case BitstreamEntry::Error:
5727       return error("Malformed block");
5728     case BitstreamEntry::EndBlock:
5729       // Done parsing VST, jump back to wherever we came from.
5730       if (Error JumpFailed = Stream.JumpToBit(CurrentBit))
5731         return JumpFailed;
5732       return Error::success();
5733     case BitstreamEntry::Record:
5734       // The interesting case.
5735       break;
5736     }
5737 
5738     // Read a record.
5739     Record.clear();
5740     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
5741     if (!MaybeRecord)
5742       return MaybeRecord.takeError();
5743     switch (MaybeRecord.get()) {
5744     default: // Default behavior: ignore (e.g. VST_CODE_BBENTRY records).
5745       break;
5746     case bitc::VST_CODE_ENTRY: { // VST_CODE_ENTRY: [valueid, namechar x N]
5747       if (convertToString(Record, 1, ValueName))
5748         return error("Invalid record");
5749       unsigned ValueID = Record[0];
5750       assert(!SourceFileName.empty());
5751       auto VLI = ValueIdToLinkageMap.find(ValueID);
5752       assert(VLI != ValueIdToLinkageMap.end() &&
5753              "No linkage found for VST entry?");
5754       auto Linkage = VLI->second;
5755       setValueGUID(ValueID, ValueName, Linkage, SourceFileName);
5756       ValueName.clear();
5757       break;
5758     }
5759     case bitc::VST_CODE_FNENTRY: {
5760       // VST_CODE_FNENTRY: [valueid, offset, namechar x N]
5761       if (convertToString(Record, 2, ValueName))
5762         return error("Invalid record");
5763       unsigned ValueID = Record[0];
5764       assert(!SourceFileName.empty());
5765       auto VLI = ValueIdToLinkageMap.find(ValueID);
5766       assert(VLI != ValueIdToLinkageMap.end() &&
5767              "No linkage found for VST entry?");
5768       auto Linkage = VLI->second;
5769       setValueGUID(ValueID, ValueName, Linkage, SourceFileName);
5770       ValueName.clear();
5771       break;
5772     }
5773     case bitc::VST_CODE_COMBINED_ENTRY: {
5774       // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
5775       unsigned ValueID = Record[0];
5776       GlobalValue::GUID RefGUID = Record[1];
5777       // The "original name", which is the second value of the pair will be
5778       // overriden later by a FS_COMBINED_ORIGINAL_NAME in the combined index.
5779       ValueIdToValueInfoMap[ValueID] =
5780           std::make_pair(TheIndex.getOrInsertValueInfo(RefGUID), RefGUID);
5781       break;
5782     }
5783     }
5784   }
5785 }
5786 
5787 // Parse just the blocks needed for building the index out of the module.
5788 // At the end of this routine the module Index is populated with a map
5789 // from global value id to GlobalValueSummary objects.
5790 Error ModuleSummaryIndexBitcodeReader::parseModule() {
5791   if (Error Err = Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
5792     return Err;
5793 
5794   SmallVector<uint64_t, 64> Record;
5795   DenseMap<unsigned, GlobalValue::LinkageTypes> ValueIdToLinkageMap;
5796   unsigned ValueId = 0;
5797 
5798   // Read the index for this module.
5799   while (true) {
5800     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
5801     if (!MaybeEntry)
5802       return MaybeEntry.takeError();
5803     llvm::BitstreamEntry Entry = MaybeEntry.get();
5804 
5805     switch (Entry.Kind) {
5806     case BitstreamEntry::Error:
5807       return error("Malformed block");
5808     case BitstreamEntry::EndBlock:
5809       return Error::success();
5810 
5811     case BitstreamEntry::SubBlock:
5812       switch (Entry.ID) {
5813       default: // Skip unknown content.
5814         if (Error Err = Stream.SkipBlock())
5815           return Err;
5816         break;
5817       case bitc::BLOCKINFO_BLOCK_ID:
5818         // Need to parse these to get abbrev ids (e.g. for VST)
5819         if (readBlockInfo())
5820           return error("Malformed block");
5821         break;
5822       case bitc::VALUE_SYMTAB_BLOCK_ID:
5823         // Should have been parsed earlier via VSTOffset, unless there
5824         // is no summary section.
5825         assert(((SeenValueSymbolTable && VSTOffset > 0) ||
5826                 !SeenGlobalValSummary) &&
5827                "Expected early VST parse via VSTOffset record");
5828         if (Error Err = Stream.SkipBlock())
5829           return Err;
5830         break;
5831       case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
5832       case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
5833         // Add the module if it is a per-module index (has a source file name).
5834         if (!SourceFileName.empty())
5835           addThisModule();
5836         assert(!SeenValueSymbolTable &&
5837                "Already read VST when parsing summary block?");
5838         // We might not have a VST if there were no values in the
5839         // summary. An empty summary block generated when we are
5840         // performing ThinLTO compiles so we don't later invoke
5841         // the regular LTO process on them.
5842         if (VSTOffset > 0) {
5843           if (Error Err = parseValueSymbolTable(VSTOffset, ValueIdToLinkageMap))
5844             return Err;
5845           SeenValueSymbolTable = true;
5846         }
5847         SeenGlobalValSummary = true;
5848         if (Error Err = parseEntireSummary(Entry.ID))
5849           return Err;
5850         break;
5851       case bitc::MODULE_STRTAB_BLOCK_ID:
5852         if (Error Err = parseModuleStringTable())
5853           return Err;
5854         break;
5855       }
5856       continue;
5857 
5858     case BitstreamEntry::Record: {
5859         Record.clear();
5860         Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
5861         if (!MaybeBitCode)
5862           return MaybeBitCode.takeError();
5863         switch (MaybeBitCode.get()) {
5864         default:
5865           break; // Default behavior, ignore unknown content.
5866         case bitc::MODULE_CODE_VERSION: {
5867           if (Error Err = parseVersionRecord(Record).takeError())
5868             return Err;
5869           break;
5870         }
5871         /// MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5872         case bitc::MODULE_CODE_SOURCE_FILENAME: {
5873           SmallString<128> ValueName;
5874           if (convertToString(Record, 0, ValueName))
5875             return error("Invalid record");
5876           SourceFileName = ValueName.c_str();
5877           break;
5878         }
5879         /// MODULE_CODE_HASH: [5*i32]
5880         case bitc::MODULE_CODE_HASH: {
5881           if (Record.size() != 5)
5882             return error("Invalid hash length " + Twine(Record.size()).str());
5883           auto &Hash = getThisModule()->second.second;
5884           int Pos = 0;
5885           for (auto &Val : Record) {
5886             assert(!(Val >> 32) && "Unexpected high bits set");
5887             Hash[Pos++] = Val;
5888           }
5889           break;
5890         }
5891         /// MODULE_CODE_VSTOFFSET: [offset]
5892         case bitc::MODULE_CODE_VSTOFFSET:
5893           if (Record.empty())
5894             return error("Invalid record");
5895           // Note that we subtract 1 here because the offset is relative to one
5896           // word before the start of the identification or module block, which
5897           // was historically always the start of the regular bitcode header.
5898           VSTOffset = Record[0] - 1;
5899           break;
5900         // v1 GLOBALVAR: [pointer type, isconst,     initid,       linkage, ...]
5901         // v1 FUNCTION:  [type,         callingconv, isproto,      linkage, ...]
5902         // v1 ALIAS:     [alias type,   addrspace,   aliasee val#, linkage, ...]
5903         // v2: [strtab offset, strtab size, v1]
5904         case bitc::MODULE_CODE_GLOBALVAR:
5905         case bitc::MODULE_CODE_FUNCTION:
5906         case bitc::MODULE_CODE_ALIAS: {
5907           StringRef Name;
5908           ArrayRef<uint64_t> GVRecord;
5909           std::tie(Name, GVRecord) = readNameFromStrtab(Record);
5910           if (GVRecord.size() <= 3)
5911             return error("Invalid record");
5912           uint64_t RawLinkage = GVRecord[3];
5913           GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
5914           if (!UseStrtab) {
5915             ValueIdToLinkageMap[ValueId++] = Linkage;
5916             break;
5917           }
5918 
5919           setValueGUID(ValueId++, Name, Linkage, SourceFileName);
5920           break;
5921         }
5922         }
5923       }
5924       continue;
5925     }
5926   }
5927 }
5928 
5929 std::vector<ValueInfo>
5930 ModuleSummaryIndexBitcodeReader::makeRefList(ArrayRef<uint64_t> Record) {
5931   std::vector<ValueInfo> Ret;
5932   Ret.reserve(Record.size());
5933   for (uint64_t RefValueId : Record)
5934     Ret.push_back(getValueInfoFromValueId(RefValueId).first);
5935   return Ret;
5936 }
5937 
5938 std::vector<FunctionSummary::EdgeTy>
5939 ModuleSummaryIndexBitcodeReader::makeCallList(ArrayRef<uint64_t> Record,
5940                                               bool IsOldProfileFormat,
5941                                               bool HasProfile, bool HasRelBF) {
5942   std::vector<FunctionSummary::EdgeTy> Ret;
5943   Ret.reserve(Record.size());
5944   for (unsigned I = 0, E = Record.size(); I != E; ++I) {
5945     CalleeInfo::HotnessType Hotness = CalleeInfo::HotnessType::Unknown;
5946     uint64_t RelBF = 0;
5947     ValueInfo Callee = getValueInfoFromValueId(Record[I]).first;
5948     if (IsOldProfileFormat) {
5949       I += 1; // Skip old callsitecount field
5950       if (HasProfile)
5951         I += 1; // Skip old profilecount field
5952     } else if (HasProfile)
5953       Hotness = static_cast<CalleeInfo::HotnessType>(Record[++I]);
5954     else if (HasRelBF)
5955       RelBF = Record[++I];
5956     Ret.push_back(FunctionSummary::EdgeTy{Callee, CalleeInfo(Hotness, RelBF)});
5957   }
5958   return Ret;
5959 }
5960 
5961 static void
5962 parseWholeProgramDevirtResolutionByArg(ArrayRef<uint64_t> Record, size_t &Slot,
5963                                        WholeProgramDevirtResolution &Wpd) {
5964   uint64_t ArgNum = Record[Slot++];
5965   WholeProgramDevirtResolution::ByArg &B =
5966       Wpd.ResByArg[{Record.begin() + Slot, Record.begin() + Slot + ArgNum}];
5967   Slot += ArgNum;
5968 
5969   B.TheKind =
5970       static_cast<WholeProgramDevirtResolution::ByArg::Kind>(Record[Slot++]);
5971   B.Info = Record[Slot++];
5972   B.Byte = Record[Slot++];
5973   B.Bit = Record[Slot++];
5974 }
5975 
5976 static void parseWholeProgramDevirtResolution(ArrayRef<uint64_t> Record,
5977                                               StringRef Strtab, size_t &Slot,
5978                                               TypeIdSummary &TypeId) {
5979   uint64_t Id = Record[Slot++];
5980   WholeProgramDevirtResolution &Wpd = TypeId.WPDRes[Id];
5981 
5982   Wpd.TheKind = static_cast<WholeProgramDevirtResolution::Kind>(Record[Slot++]);
5983   Wpd.SingleImplName = {Strtab.data() + Record[Slot],
5984                         static_cast<size_t>(Record[Slot + 1])};
5985   Slot += 2;
5986 
5987   uint64_t ResByArgNum = Record[Slot++];
5988   for (uint64_t I = 0; I != ResByArgNum; ++I)
5989     parseWholeProgramDevirtResolutionByArg(Record, Slot, Wpd);
5990 }
5991 
5992 static void parseTypeIdSummaryRecord(ArrayRef<uint64_t> Record,
5993                                      StringRef Strtab,
5994                                      ModuleSummaryIndex &TheIndex) {
5995   size_t Slot = 0;
5996   TypeIdSummary &TypeId = TheIndex.getOrInsertTypeIdSummary(
5997       {Strtab.data() + Record[Slot], static_cast<size_t>(Record[Slot + 1])});
5998   Slot += 2;
5999 
6000   TypeId.TTRes.TheKind = static_cast<TypeTestResolution::Kind>(Record[Slot++]);
6001   TypeId.TTRes.SizeM1BitWidth = Record[Slot++];
6002   TypeId.TTRes.AlignLog2 = Record[Slot++];
6003   TypeId.TTRes.SizeM1 = Record[Slot++];
6004   TypeId.TTRes.BitMask = Record[Slot++];
6005   TypeId.TTRes.InlineBits = Record[Slot++];
6006 
6007   while (Slot < Record.size())
6008     parseWholeProgramDevirtResolution(Record, Strtab, Slot, TypeId);
6009 }
6010 
6011 std::vector<FunctionSummary::ParamAccess>
6012 ModuleSummaryIndexBitcodeReader::parseParamAccesses(ArrayRef<uint64_t> Record) {
6013   auto ReadRange = [&]() {
6014     APInt Lower(FunctionSummary::ParamAccess::RangeWidth,
6015                 BitcodeReader::decodeSignRotatedValue(Record.front()));
6016     Record = Record.drop_front();
6017     APInt Upper(FunctionSummary::ParamAccess::RangeWidth,
6018                 BitcodeReader::decodeSignRotatedValue(Record.front()));
6019     Record = Record.drop_front();
6020     ConstantRange Range{Lower, Upper};
6021     assert(!Range.isFullSet());
6022     assert(!Range.isUpperSignWrapped());
6023     return Range;
6024   };
6025 
6026   std::vector<FunctionSummary::ParamAccess> PendingParamAccesses;
6027   while (!Record.empty()) {
6028     PendingParamAccesses.emplace_back();
6029     FunctionSummary::ParamAccess &ParamAccess = PendingParamAccesses.back();
6030     ParamAccess.ParamNo = Record.front();
6031     Record = Record.drop_front();
6032     ParamAccess.Use = ReadRange();
6033     ParamAccess.Calls.resize(Record.front());
6034     Record = Record.drop_front();
6035     for (auto &Call : ParamAccess.Calls) {
6036       Call.ParamNo = Record.front();
6037       Record = Record.drop_front();
6038       Call.Callee = getValueInfoFromValueId(Record.front()).first;
6039       Record = Record.drop_front();
6040       Call.Offsets = ReadRange();
6041     }
6042   }
6043   return PendingParamAccesses;
6044 }
6045 
6046 void ModuleSummaryIndexBitcodeReader::parseTypeIdCompatibleVtableInfo(
6047     ArrayRef<uint64_t> Record, size_t &Slot,
6048     TypeIdCompatibleVtableInfo &TypeId) {
6049   uint64_t Offset = Record[Slot++];
6050   ValueInfo Callee = getValueInfoFromValueId(Record[Slot++]).first;
6051   TypeId.push_back({Offset, Callee});
6052 }
6053 
6054 void ModuleSummaryIndexBitcodeReader::parseTypeIdCompatibleVtableSummaryRecord(
6055     ArrayRef<uint64_t> Record) {
6056   size_t Slot = 0;
6057   TypeIdCompatibleVtableInfo &TypeId =
6058       TheIndex.getOrInsertTypeIdCompatibleVtableSummary(
6059           {Strtab.data() + Record[Slot],
6060            static_cast<size_t>(Record[Slot + 1])});
6061   Slot += 2;
6062 
6063   while (Slot < Record.size())
6064     parseTypeIdCompatibleVtableInfo(Record, Slot, TypeId);
6065 }
6066 
6067 static void setSpecialRefs(std::vector<ValueInfo> &Refs, unsigned ROCnt,
6068                            unsigned WOCnt) {
6069   // Readonly and writeonly refs are in the end of the refs list.
6070   assert(ROCnt + WOCnt <= Refs.size());
6071   unsigned FirstWORef = Refs.size() - WOCnt;
6072   unsigned RefNo = FirstWORef - ROCnt;
6073   for (; RefNo < FirstWORef; ++RefNo)
6074     Refs[RefNo].setReadOnly();
6075   for (; RefNo < Refs.size(); ++RefNo)
6076     Refs[RefNo].setWriteOnly();
6077 }
6078 
6079 // Eagerly parse the entire summary block. This populates the GlobalValueSummary
6080 // objects in the index.
6081 Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
6082   if (Error Err = Stream.EnterSubBlock(ID))
6083     return Err;
6084   SmallVector<uint64_t, 64> Record;
6085 
6086   // Parse version
6087   {
6088     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
6089     if (!MaybeEntry)
6090       return MaybeEntry.takeError();
6091     BitstreamEntry Entry = MaybeEntry.get();
6092 
6093     if (Entry.Kind != BitstreamEntry::Record)
6094       return error("Invalid Summary Block: record for version expected");
6095     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
6096     if (!MaybeRecord)
6097       return MaybeRecord.takeError();
6098     if (MaybeRecord.get() != bitc::FS_VERSION)
6099       return error("Invalid Summary Block: version expected");
6100   }
6101   const uint64_t Version = Record[0];
6102   const bool IsOldProfileFormat = Version == 1;
6103   if (Version < 1 || Version > ModuleSummaryIndex::BitcodeSummaryVersion)
6104     return error("Invalid summary version " + Twine(Version) +
6105                  ". Version should be in the range [1-" +
6106                  Twine(ModuleSummaryIndex::BitcodeSummaryVersion) +
6107                  "].");
6108   Record.clear();
6109 
6110   // Keep around the last seen summary to be used when we see an optional
6111   // "OriginalName" attachement.
6112   GlobalValueSummary *LastSeenSummary = nullptr;
6113   GlobalValue::GUID LastSeenGUID = 0;
6114 
6115   // We can expect to see any number of type ID information records before
6116   // each function summary records; these variables store the information
6117   // collected so far so that it can be used to create the summary object.
6118   std::vector<GlobalValue::GUID> PendingTypeTests;
6119   std::vector<FunctionSummary::VFuncId> PendingTypeTestAssumeVCalls,
6120       PendingTypeCheckedLoadVCalls;
6121   std::vector<FunctionSummary::ConstVCall> PendingTypeTestAssumeConstVCalls,
6122       PendingTypeCheckedLoadConstVCalls;
6123   std::vector<FunctionSummary::ParamAccess> PendingParamAccesses;
6124 
6125   while (true) {
6126     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
6127     if (!MaybeEntry)
6128       return MaybeEntry.takeError();
6129     BitstreamEntry Entry = MaybeEntry.get();
6130 
6131     switch (Entry.Kind) {
6132     case BitstreamEntry::SubBlock: // Handled for us already.
6133     case BitstreamEntry::Error:
6134       return error("Malformed block");
6135     case BitstreamEntry::EndBlock:
6136       return Error::success();
6137     case BitstreamEntry::Record:
6138       // The interesting case.
6139       break;
6140     }
6141 
6142     // Read a record. The record format depends on whether this
6143     // is a per-module index or a combined index file. In the per-module
6144     // case the records contain the associated value's ID for correlation
6145     // with VST entries. In the combined index the correlation is done
6146     // via the bitcode offset of the summary records (which were saved
6147     // in the combined index VST entries). The records also contain
6148     // information used for ThinLTO renaming and importing.
6149     Record.clear();
6150     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
6151     if (!MaybeBitCode)
6152       return MaybeBitCode.takeError();
6153     switch (unsigned BitCode = MaybeBitCode.get()) {
6154     default: // Default behavior: ignore.
6155       break;
6156     case bitc::FS_FLAGS: {  // [flags]
6157       TheIndex.setFlags(Record[0]);
6158       break;
6159     }
6160     case bitc::FS_VALUE_GUID: { // [valueid, refguid]
6161       uint64_t ValueID = Record[0];
6162       GlobalValue::GUID RefGUID = Record[1];
6163       ValueIdToValueInfoMap[ValueID] =
6164           std::make_pair(TheIndex.getOrInsertValueInfo(RefGUID), RefGUID);
6165       break;
6166     }
6167     // FS_PERMODULE: [valueid, flags, instcount, fflags, numrefs,
6168     //                numrefs x valueid, n x (valueid)]
6169     // FS_PERMODULE_PROFILE: [valueid, flags, instcount, fflags, numrefs,
6170     //                        numrefs x valueid,
6171     //                        n x (valueid, hotness)]
6172     // FS_PERMODULE_RELBF: [valueid, flags, instcount, fflags, numrefs,
6173     //                      numrefs x valueid,
6174     //                      n x (valueid, relblockfreq)]
6175     case bitc::FS_PERMODULE:
6176     case bitc::FS_PERMODULE_RELBF:
6177     case bitc::FS_PERMODULE_PROFILE: {
6178       unsigned ValueID = Record[0];
6179       uint64_t RawFlags = Record[1];
6180       unsigned InstCount = Record[2];
6181       uint64_t RawFunFlags = 0;
6182       unsigned NumRefs = Record[3];
6183       unsigned NumRORefs = 0, NumWORefs = 0;
6184       int RefListStartIndex = 4;
6185       if (Version >= 4) {
6186         RawFunFlags = Record[3];
6187         NumRefs = Record[4];
6188         RefListStartIndex = 5;
6189         if (Version >= 5) {
6190           NumRORefs = Record[5];
6191           RefListStartIndex = 6;
6192           if (Version >= 7) {
6193             NumWORefs = Record[6];
6194             RefListStartIndex = 7;
6195           }
6196         }
6197       }
6198 
6199       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6200       // The module path string ref set in the summary must be owned by the
6201       // index's module string table. Since we don't have a module path
6202       // string table section in the per-module index, we create a single
6203       // module path string table entry with an empty (0) ID to take
6204       // ownership.
6205       int CallGraphEdgeStartIndex = RefListStartIndex + NumRefs;
6206       assert(Record.size() >= RefListStartIndex + NumRefs &&
6207              "Record size inconsistent with number of references");
6208       std::vector<ValueInfo> Refs = makeRefList(
6209           ArrayRef<uint64_t>(Record).slice(RefListStartIndex, NumRefs));
6210       bool HasProfile = (BitCode == bitc::FS_PERMODULE_PROFILE);
6211       bool HasRelBF = (BitCode == bitc::FS_PERMODULE_RELBF);
6212       std::vector<FunctionSummary::EdgeTy> Calls = makeCallList(
6213           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
6214           IsOldProfileFormat, HasProfile, HasRelBF);
6215       setSpecialRefs(Refs, NumRORefs, NumWORefs);
6216       auto FS = std::make_unique<FunctionSummary>(
6217           Flags, InstCount, getDecodedFFlags(RawFunFlags), /*EntryCount=*/0,
6218           std::move(Refs), std::move(Calls), std::move(PendingTypeTests),
6219           std::move(PendingTypeTestAssumeVCalls),
6220           std::move(PendingTypeCheckedLoadVCalls),
6221           std::move(PendingTypeTestAssumeConstVCalls),
6222           std::move(PendingTypeCheckedLoadConstVCalls),
6223           std::move(PendingParamAccesses));
6224       auto VIAndOriginalGUID = getValueInfoFromValueId(ValueID);
6225       FS->setModulePath(getThisModule()->first());
6226       FS->setOriginalName(VIAndOriginalGUID.second);
6227       TheIndex.addGlobalValueSummary(VIAndOriginalGUID.first, std::move(FS));
6228       break;
6229     }
6230     // FS_ALIAS: [valueid, flags, valueid]
6231     // Aliases must be emitted (and parsed) after all FS_PERMODULE entries, as
6232     // they expect all aliasee summaries to be available.
6233     case bitc::FS_ALIAS: {
6234       unsigned ValueID = Record[0];
6235       uint64_t RawFlags = Record[1];
6236       unsigned AliaseeID = Record[2];
6237       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6238       auto AS = std::make_unique<AliasSummary>(Flags);
6239       // The module path string ref set in the summary must be owned by the
6240       // index's module string table. Since we don't have a module path
6241       // string table section in the per-module index, we create a single
6242       // module path string table entry with an empty (0) ID to take
6243       // ownership.
6244       AS->setModulePath(getThisModule()->first());
6245 
6246       auto AliaseeVI = getValueInfoFromValueId(AliaseeID).first;
6247       auto AliaseeInModule = TheIndex.findSummaryInModule(AliaseeVI, ModulePath);
6248       if (!AliaseeInModule)
6249         return error("Alias expects aliasee summary to be parsed");
6250       AS->setAliasee(AliaseeVI, AliaseeInModule);
6251 
6252       auto GUID = getValueInfoFromValueId(ValueID);
6253       AS->setOriginalName(GUID.second);
6254       TheIndex.addGlobalValueSummary(GUID.first, std::move(AS));
6255       break;
6256     }
6257     // FS_PERMODULE_GLOBALVAR_INIT_REFS: [valueid, flags, varflags, n x valueid]
6258     case bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS: {
6259       unsigned ValueID = Record[0];
6260       uint64_t RawFlags = Record[1];
6261       unsigned RefArrayStart = 2;
6262       GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
6263                                       /* WriteOnly */ false,
6264                                       /* Constant */ false,
6265                                       GlobalObject::VCallVisibilityPublic);
6266       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6267       if (Version >= 5) {
6268         GVF = getDecodedGVarFlags(Record[2]);
6269         RefArrayStart = 3;
6270       }
6271       std::vector<ValueInfo> Refs =
6272           makeRefList(ArrayRef<uint64_t>(Record).slice(RefArrayStart));
6273       auto FS =
6274           std::make_unique<GlobalVarSummary>(Flags, GVF, std::move(Refs));
6275       FS->setModulePath(getThisModule()->first());
6276       auto GUID = getValueInfoFromValueId(ValueID);
6277       FS->setOriginalName(GUID.second);
6278       TheIndex.addGlobalValueSummary(GUID.first, std::move(FS));
6279       break;
6280     }
6281     // FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS: [valueid, flags, varflags,
6282     //                        numrefs, numrefs x valueid,
6283     //                        n x (valueid, offset)]
6284     case bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS: {
6285       unsigned ValueID = Record[0];
6286       uint64_t RawFlags = Record[1];
6287       GlobalVarSummary::GVarFlags GVF = getDecodedGVarFlags(Record[2]);
6288       unsigned NumRefs = Record[3];
6289       unsigned RefListStartIndex = 4;
6290       unsigned VTableListStartIndex = RefListStartIndex + NumRefs;
6291       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6292       std::vector<ValueInfo> Refs = makeRefList(
6293           ArrayRef<uint64_t>(Record).slice(RefListStartIndex, NumRefs));
6294       VTableFuncList VTableFuncs;
6295       for (unsigned I = VTableListStartIndex, E = Record.size(); I != E; ++I) {
6296         ValueInfo Callee = getValueInfoFromValueId(Record[I]).first;
6297         uint64_t Offset = Record[++I];
6298         VTableFuncs.push_back({Callee, Offset});
6299       }
6300       auto VS =
6301           std::make_unique<GlobalVarSummary>(Flags, GVF, std::move(Refs));
6302       VS->setModulePath(getThisModule()->first());
6303       VS->setVTableFuncs(VTableFuncs);
6304       auto GUID = getValueInfoFromValueId(ValueID);
6305       VS->setOriginalName(GUID.second);
6306       TheIndex.addGlobalValueSummary(GUID.first, std::move(VS));
6307       break;
6308     }
6309     // FS_COMBINED: [valueid, modid, flags, instcount, fflags, numrefs,
6310     //               numrefs x valueid, n x (valueid)]
6311     // FS_COMBINED_PROFILE: [valueid, modid, flags, instcount, fflags, numrefs,
6312     //                       numrefs x valueid, n x (valueid, hotness)]
6313     case bitc::FS_COMBINED:
6314     case bitc::FS_COMBINED_PROFILE: {
6315       unsigned ValueID = Record[0];
6316       uint64_t ModuleId = Record[1];
6317       uint64_t RawFlags = Record[2];
6318       unsigned InstCount = Record[3];
6319       uint64_t RawFunFlags = 0;
6320       uint64_t EntryCount = 0;
6321       unsigned NumRefs = Record[4];
6322       unsigned NumRORefs = 0, NumWORefs = 0;
6323       int RefListStartIndex = 5;
6324 
6325       if (Version >= 4) {
6326         RawFunFlags = Record[4];
6327         RefListStartIndex = 6;
6328         size_t NumRefsIndex = 5;
6329         if (Version >= 5) {
6330           unsigned NumRORefsOffset = 1;
6331           RefListStartIndex = 7;
6332           if (Version >= 6) {
6333             NumRefsIndex = 6;
6334             EntryCount = Record[5];
6335             RefListStartIndex = 8;
6336             if (Version >= 7) {
6337               RefListStartIndex = 9;
6338               NumWORefs = Record[8];
6339               NumRORefsOffset = 2;
6340             }
6341           }
6342           NumRORefs = Record[RefListStartIndex - NumRORefsOffset];
6343         }
6344         NumRefs = Record[NumRefsIndex];
6345       }
6346 
6347       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6348       int CallGraphEdgeStartIndex = RefListStartIndex + NumRefs;
6349       assert(Record.size() >= RefListStartIndex + NumRefs &&
6350              "Record size inconsistent with number of references");
6351       std::vector<ValueInfo> Refs = makeRefList(
6352           ArrayRef<uint64_t>(Record).slice(RefListStartIndex, NumRefs));
6353       bool HasProfile = (BitCode == bitc::FS_COMBINED_PROFILE);
6354       std::vector<FunctionSummary::EdgeTy> Edges = makeCallList(
6355           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
6356           IsOldProfileFormat, HasProfile, false);
6357       ValueInfo VI = getValueInfoFromValueId(ValueID).first;
6358       setSpecialRefs(Refs, NumRORefs, NumWORefs);
6359       auto FS = std::make_unique<FunctionSummary>(
6360           Flags, InstCount, getDecodedFFlags(RawFunFlags), EntryCount,
6361           std::move(Refs), std::move(Edges), std::move(PendingTypeTests),
6362           std::move(PendingTypeTestAssumeVCalls),
6363           std::move(PendingTypeCheckedLoadVCalls),
6364           std::move(PendingTypeTestAssumeConstVCalls),
6365           std::move(PendingTypeCheckedLoadConstVCalls),
6366           std::move(PendingParamAccesses));
6367       LastSeenSummary = FS.get();
6368       LastSeenGUID = VI.getGUID();
6369       FS->setModulePath(ModuleIdMap[ModuleId]);
6370       TheIndex.addGlobalValueSummary(VI, std::move(FS));
6371       break;
6372     }
6373     // FS_COMBINED_ALIAS: [valueid, modid, flags, valueid]
6374     // Aliases must be emitted (and parsed) after all FS_COMBINED entries, as
6375     // they expect all aliasee summaries to be available.
6376     case bitc::FS_COMBINED_ALIAS: {
6377       unsigned ValueID = Record[0];
6378       uint64_t ModuleId = Record[1];
6379       uint64_t RawFlags = Record[2];
6380       unsigned AliaseeValueId = Record[3];
6381       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6382       auto AS = std::make_unique<AliasSummary>(Flags);
6383       LastSeenSummary = AS.get();
6384       AS->setModulePath(ModuleIdMap[ModuleId]);
6385 
6386       auto AliaseeVI = getValueInfoFromValueId(AliaseeValueId).first;
6387       auto AliaseeInModule = TheIndex.findSummaryInModule(AliaseeVI, AS->modulePath());
6388       AS->setAliasee(AliaseeVI, AliaseeInModule);
6389 
6390       ValueInfo VI = getValueInfoFromValueId(ValueID).first;
6391       LastSeenGUID = VI.getGUID();
6392       TheIndex.addGlobalValueSummary(VI, std::move(AS));
6393       break;
6394     }
6395     // FS_COMBINED_GLOBALVAR_INIT_REFS: [valueid, modid, flags, n x valueid]
6396     case bitc::FS_COMBINED_GLOBALVAR_INIT_REFS: {
6397       unsigned ValueID = Record[0];
6398       uint64_t ModuleId = Record[1];
6399       uint64_t RawFlags = Record[2];
6400       unsigned RefArrayStart = 3;
6401       GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
6402                                       /* WriteOnly */ false,
6403                                       /* Constant */ false,
6404                                       GlobalObject::VCallVisibilityPublic);
6405       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
6406       if (Version >= 5) {
6407         GVF = getDecodedGVarFlags(Record[3]);
6408         RefArrayStart = 4;
6409       }
6410       std::vector<ValueInfo> Refs =
6411           makeRefList(ArrayRef<uint64_t>(Record).slice(RefArrayStart));
6412       auto FS =
6413           std::make_unique<GlobalVarSummary>(Flags, GVF, std::move(Refs));
6414       LastSeenSummary = FS.get();
6415       FS->setModulePath(ModuleIdMap[ModuleId]);
6416       ValueInfo VI = getValueInfoFromValueId(ValueID).first;
6417       LastSeenGUID = VI.getGUID();
6418       TheIndex.addGlobalValueSummary(VI, std::move(FS));
6419       break;
6420     }
6421     // FS_COMBINED_ORIGINAL_NAME: [original_name]
6422     case bitc::FS_COMBINED_ORIGINAL_NAME: {
6423       uint64_t OriginalName = Record[0];
6424       if (!LastSeenSummary)
6425         return error("Name attachment that does not follow a combined record");
6426       LastSeenSummary->setOriginalName(OriginalName);
6427       TheIndex.addOriginalName(LastSeenGUID, OriginalName);
6428       // Reset the LastSeenSummary
6429       LastSeenSummary = nullptr;
6430       LastSeenGUID = 0;
6431       break;
6432     }
6433     case bitc::FS_TYPE_TESTS:
6434       assert(PendingTypeTests.empty());
6435       llvm::append_range(PendingTypeTests, Record);
6436       break;
6437 
6438     case bitc::FS_TYPE_TEST_ASSUME_VCALLS:
6439       assert(PendingTypeTestAssumeVCalls.empty());
6440       for (unsigned I = 0; I != Record.size(); I += 2)
6441         PendingTypeTestAssumeVCalls.push_back({Record[I], Record[I+1]});
6442       break;
6443 
6444     case bitc::FS_TYPE_CHECKED_LOAD_VCALLS:
6445       assert(PendingTypeCheckedLoadVCalls.empty());
6446       for (unsigned I = 0; I != Record.size(); I += 2)
6447         PendingTypeCheckedLoadVCalls.push_back({Record[I], Record[I+1]});
6448       break;
6449 
6450     case bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL:
6451       PendingTypeTestAssumeConstVCalls.push_back(
6452           {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
6453       break;
6454 
6455     case bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL:
6456       PendingTypeCheckedLoadConstVCalls.push_back(
6457           {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
6458       break;
6459 
6460     case bitc::FS_CFI_FUNCTION_DEFS: {
6461       std::set<std::string> &CfiFunctionDefs = TheIndex.cfiFunctionDefs();
6462       for (unsigned I = 0; I != Record.size(); I += 2)
6463         CfiFunctionDefs.insert(
6464             {Strtab.data() + Record[I], static_cast<size_t>(Record[I + 1])});
6465       break;
6466     }
6467 
6468     case bitc::FS_CFI_FUNCTION_DECLS: {
6469       std::set<std::string> &CfiFunctionDecls = TheIndex.cfiFunctionDecls();
6470       for (unsigned I = 0; I != Record.size(); I += 2)
6471         CfiFunctionDecls.insert(
6472             {Strtab.data() + Record[I], static_cast<size_t>(Record[I + 1])});
6473       break;
6474     }
6475 
6476     case bitc::FS_TYPE_ID:
6477       parseTypeIdSummaryRecord(Record, Strtab, TheIndex);
6478       break;
6479 
6480     case bitc::FS_TYPE_ID_METADATA:
6481       parseTypeIdCompatibleVtableSummaryRecord(Record);
6482       break;
6483 
6484     case bitc::FS_BLOCK_COUNT:
6485       TheIndex.addBlockCount(Record[0]);
6486       break;
6487 
6488     case bitc::FS_PARAM_ACCESS: {
6489       PendingParamAccesses = parseParamAccesses(Record);
6490       break;
6491     }
6492     }
6493   }
6494   llvm_unreachable("Exit infinite loop");
6495 }
6496 
6497 // Parse the  module string table block into the Index.
6498 // This populates the ModulePathStringTable map in the index.
6499 Error ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {
6500   if (Error Err = Stream.EnterSubBlock(bitc::MODULE_STRTAB_BLOCK_ID))
6501     return Err;
6502 
6503   SmallVector<uint64_t, 64> Record;
6504 
6505   SmallString<128> ModulePath;
6506   ModuleSummaryIndex::ModuleInfo *LastSeenModule = nullptr;
6507 
6508   while (true) {
6509     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
6510     if (!MaybeEntry)
6511       return MaybeEntry.takeError();
6512     BitstreamEntry Entry = MaybeEntry.get();
6513 
6514     switch (Entry.Kind) {
6515     case BitstreamEntry::SubBlock: // Handled for us already.
6516     case BitstreamEntry::Error:
6517       return error("Malformed block");
6518     case BitstreamEntry::EndBlock:
6519       return Error::success();
6520     case BitstreamEntry::Record:
6521       // The interesting case.
6522       break;
6523     }
6524 
6525     Record.clear();
6526     Expected<unsigned> MaybeRecord = Stream.readRecord(Entry.ID, Record);
6527     if (!MaybeRecord)
6528       return MaybeRecord.takeError();
6529     switch (MaybeRecord.get()) {
6530     default: // Default behavior: ignore.
6531       break;
6532     case bitc::MST_CODE_ENTRY: {
6533       // MST_ENTRY: [modid, namechar x N]
6534       uint64_t ModuleId = Record[0];
6535 
6536       if (convertToString(Record, 1, ModulePath))
6537         return error("Invalid record");
6538 
6539       LastSeenModule = TheIndex.addModule(ModulePath, ModuleId);
6540       ModuleIdMap[ModuleId] = LastSeenModule->first();
6541 
6542       ModulePath.clear();
6543       break;
6544     }
6545     /// MST_CODE_HASH: [5*i32]
6546     case bitc::MST_CODE_HASH: {
6547       if (Record.size() != 5)
6548         return error("Invalid hash length " + Twine(Record.size()).str());
6549       if (!LastSeenModule)
6550         return error("Invalid hash that does not follow a module path");
6551       int Pos = 0;
6552       for (auto &Val : Record) {
6553         assert(!(Val >> 32) && "Unexpected high bits set");
6554         LastSeenModule->second.second[Pos++] = Val;
6555       }
6556       // Reset LastSeenModule to avoid overriding the hash unexpectedly.
6557       LastSeenModule = nullptr;
6558       break;
6559     }
6560     }
6561   }
6562   llvm_unreachable("Exit infinite loop");
6563 }
6564 
6565 namespace {
6566 
6567 // FIXME: This class is only here to support the transition to llvm::Error. It
6568 // will be removed once this transition is complete. Clients should prefer to
6569 // deal with the Error value directly, rather than converting to error_code.
6570 class BitcodeErrorCategoryType : public std::error_category {
6571   const char *name() const noexcept override {
6572     return "llvm.bitcode";
6573   }
6574 
6575   std::string message(int IE) const override {
6576     BitcodeError E = static_cast<BitcodeError>(IE);
6577     switch (E) {
6578     case BitcodeError::CorruptedBitcode:
6579       return "Corrupted bitcode";
6580     }
6581     llvm_unreachable("Unknown error type!");
6582   }
6583 };
6584 
6585 } // end anonymous namespace
6586 
6587 static ManagedStatic<BitcodeErrorCategoryType> ErrorCategory;
6588 
6589 const std::error_category &llvm::BitcodeErrorCategory() {
6590   return *ErrorCategory;
6591 }
6592 
6593 static Expected<StringRef> readBlobInRecord(BitstreamCursor &Stream,
6594                                             unsigned Block, unsigned RecordID) {
6595   if (Error Err = Stream.EnterSubBlock(Block))
6596     return std::move(Err);
6597 
6598   StringRef Strtab;
6599   while (true) {
6600     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
6601     if (!MaybeEntry)
6602       return MaybeEntry.takeError();
6603     llvm::BitstreamEntry Entry = MaybeEntry.get();
6604 
6605     switch (Entry.Kind) {
6606     case BitstreamEntry::EndBlock:
6607       return Strtab;
6608 
6609     case BitstreamEntry::Error:
6610       return error("Malformed block");
6611 
6612     case BitstreamEntry::SubBlock:
6613       if (Error Err = Stream.SkipBlock())
6614         return std::move(Err);
6615       break;
6616 
6617     case BitstreamEntry::Record:
6618       StringRef Blob;
6619       SmallVector<uint64_t, 1> Record;
6620       Expected<unsigned> MaybeRecord =
6621           Stream.readRecord(Entry.ID, Record, &Blob);
6622       if (!MaybeRecord)
6623         return MaybeRecord.takeError();
6624       if (MaybeRecord.get() == RecordID)
6625         Strtab = Blob;
6626       break;
6627     }
6628   }
6629 }
6630 
6631 //===----------------------------------------------------------------------===//
6632 // External interface
6633 //===----------------------------------------------------------------------===//
6634 
6635 Expected<std::vector<BitcodeModule>>
6636 llvm::getBitcodeModuleList(MemoryBufferRef Buffer) {
6637   auto FOrErr = getBitcodeFileContents(Buffer);
6638   if (!FOrErr)
6639     return FOrErr.takeError();
6640   return std::move(FOrErr->Mods);
6641 }
6642 
6643 Expected<BitcodeFileContents>
6644 llvm::getBitcodeFileContents(MemoryBufferRef Buffer) {
6645   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
6646   if (!StreamOrErr)
6647     return StreamOrErr.takeError();
6648   BitstreamCursor &Stream = *StreamOrErr;
6649 
6650   BitcodeFileContents F;
6651   while (true) {
6652     uint64_t BCBegin = Stream.getCurrentByteNo();
6653 
6654     // We may be consuming bitcode from a client that leaves garbage at the end
6655     // of the bitcode stream (e.g. Apple's ar tool). If we are close enough to
6656     // the end that there cannot possibly be another module, stop looking.
6657     if (BCBegin + 8 >= Stream.getBitcodeBytes().size())
6658       return F;
6659 
6660     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
6661     if (!MaybeEntry)
6662       return MaybeEntry.takeError();
6663     llvm::BitstreamEntry Entry = MaybeEntry.get();
6664 
6665     switch (Entry.Kind) {
6666     case BitstreamEntry::EndBlock:
6667     case BitstreamEntry::Error:
6668       return error("Malformed block");
6669 
6670     case BitstreamEntry::SubBlock: {
6671       uint64_t IdentificationBit = -1ull;
6672       if (Entry.ID == bitc::IDENTIFICATION_BLOCK_ID) {
6673         IdentificationBit = Stream.GetCurrentBitNo() - BCBegin * 8;
6674         if (Error Err = Stream.SkipBlock())
6675           return std::move(Err);
6676 
6677         {
6678           Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
6679           if (!MaybeEntry)
6680             return MaybeEntry.takeError();
6681           Entry = MaybeEntry.get();
6682         }
6683 
6684         if (Entry.Kind != BitstreamEntry::SubBlock ||
6685             Entry.ID != bitc::MODULE_BLOCK_ID)
6686           return error("Malformed block");
6687       }
6688 
6689       if (Entry.ID == bitc::MODULE_BLOCK_ID) {
6690         uint64_t ModuleBit = Stream.GetCurrentBitNo() - BCBegin * 8;
6691         if (Error Err = Stream.SkipBlock())
6692           return std::move(Err);
6693 
6694         F.Mods.push_back({Stream.getBitcodeBytes().slice(
6695                               BCBegin, Stream.getCurrentByteNo() - BCBegin),
6696                           Buffer.getBufferIdentifier(), IdentificationBit,
6697                           ModuleBit});
6698         continue;
6699       }
6700 
6701       if (Entry.ID == bitc::STRTAB_BLOCK_ID) {
6702         Expected<StringRef> Strtab =
6703             readBlobInRecord(Stream, bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB);
6704         if (!Strtab)
6705           return Strtab.takeError();
6706         // This string table is used by every preceding bitcode module that does
6707         // not have its own string table. A bitcode file may have multiple
6708         // string tables if it was created by binary concatenation, for example
6709         // with "llvm-cat -b".
6710         for (auto I = F.Mods.rbegin(), E = F.Mods.rend(); I != E; ++I) {
6711           if (!I->Strtab.empty())
6712             break;
6713           I->Strtab = *Strtab;
6714         }
6715         // Similarly, the string table is used by every preceding symbol table;
6716         // normally there will be just one unless the bitcode file was created
6717         // by binary concatenation.
6718         if (!F.Symtab.empty() && F.StrtabForSymtab.empty())
6719           F.StrtabForSymtab = *Strtab;
6720         continue;
6721       }
6722 
6723       if (Entry.ID == bitc::SYMTAB_BLOCK_ID) {
6724         Expected<StringRef> SymtabOrErr =
6725             readBlobInRecord(Stream, bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB);
6726         if (!SymtabOrErr)
6727           return SymtabOrErr.takeError();
6728 
6729         // We can expect the bitcode file to have multiple symbol tables if it
6730         // was created by binary concatenation. In that case we silently
6731         // ignore any subsequent symbol tables, which is fine because this is a
6732         // low level function. The client is expected to notice that the number
6733         // of modules in the symbol table does not match the number of modules
6734         // in the input file and regenerate the symbol table.
6735         if (F.Symtab.empty())
6736           F.Symtab = *SymtabOrErr;
6737         continue;
6738       }
6739 
6740       if (Error Err = Stream.SkipBlock())
6741         return std::move(Err);
6742       continue;
6743     }
6744     case BitstreamEntry::Record:
6745       if (Expected<unsigned> StreamFailed = Stream.skipRecord(Entry.ID))
6746         continue;
6747       else
6748         return StreamFailed.takeError();
6749     }
6750   }
6751 }
6752 
6753 /// Get a lazy one-at-time loading module from bitcode.
6754 ///
6755 /// This isn't always used in a lazy context.  In particular, it's also used by
6756 /// \a parseModule().  If this is truly lazy, then we need to eagerly pull
6757 /// in forward-referenced functions from block address references.
6758 ///
6759 /// \param[in] MaterializeAll Set to \c true if we should materialize
6760 /// everything.
6761 Expected<std::unique_ptr<Module>>
6762 BitcodeModule::getModuleImpl(LLVMContext &Context, bool MaterializeAll,
6763                              bool ShouldLazyLoadMetadata, bool IsImporting,
6764                              DataLayoutCallbackTy DataLayoutCallback) {
6765   BitstreamCursor Stream(Buffer);
6766 
6767   std::string ProducerIdentification;
6768   if (IdentificationBit != -1ull) {
6769     if (Error JumpFailed = Stream.JumpToBit(IdentificationBit))
6770       return std::move(JumpFailed);
6771     Expected<std::string> ProducerIdentificationOrErr =
6772         readIdentificationBlock(Stream);
6773     if (!ProducerIdentificationOrErr)
6774       return ProducerIdentificationOrErr.takeError();
6775 
6776     ProducerIdentification = *ProducerIdentificationOrErr;
6777   }
6778 
6779   if (Error JumpFailed = Stream.JumpToBit(ModuleBit))
6780     return std::move(JumpFailed);
6781   auto *R = new BitcodeReader(std::move(Stream), Strtab, ProducerIdentification,
6782                               Context);
6783 
6784   std::unique_ptr<Module> M =
6785       std::make_unique<Module>(ModuleIdentifier, Context);
6786   M->setMaterializer(R);
6787 
6788   // Delay parsing Metadata if ShouldLazyLoadMetadata is true.
6789   if (Error Err = R->parseBitcodeInto(M.get(), ShouldLazyLoadMetadata,
6790                                       IsImporting, DataLayoutCallback))
6791     return std::move(Err);
6792 
6793   if (MaterializeAll) {
6794     // Read in the entire module, and destroy the BitcodeReader.
6795     if (Error Err = M->materializeAll())
6796       return std::move(Err);
6797   } else {
6798     // Resolve forward references from blockaddresses.
6799     if (Error Err = R->materializeForwardReferencedFunctions())
6800       return std::move(Err);
6801   }
6802   return std::move(M);
6803 }
6804 
6805 Expected<std::unique_ptr<Module>>
6806 BitcodeModule::getLazyModule(LLVMContext &Context, bool ShouldLazyLoadMetadata,
6807                              bool IsImporting) {
6808   return getModuleImpl(Context, false, ShouldLazyLoadMetadata, IsImporting,
6809                        [](StringRef) { return None; });
6810 }
6811 
6812 // Parse the specified bitcode buffer and merge the index into CombinedIndex.
6813 // We don't use ModuleIdentifier here because the client may need to control the
6814 // module path used in the combined summary (e.g. when reading summaries for
6815 // regular LTO modules).
6816 Error BitcodeModule::readSummary(ModuleSummaryIndex &CombinedIndex,
6817                                  StringRef ModulePath, uint64_t ModuleId) {
6818   BitstreamCursor Stream(Buffer);
6819   if (Error JumpFailed = Stream.JumpToBit(ModuleBit))
6820     return JumpFailed;
6821 
6822   ModuleSummaryIndexBitcodeReader R(std::move(Stream), Strtab, CombinedIndex,
6823                                     ModulePath, ModuleId);
6824   return R.parseModule();
6825 }
6826 
6827 // Parse the specified bitcode buffer, returning the function info index.
6828 Expected<std::unique_ptr<ModuleSummaryIndex>> BitcodeModule::getSummary() {
6829   BitstreamCursor Stream(Buffer);
6830   if (Error JumpFailed = Stream.JumpToBit(ModuleBit))
6831     return std::move(JumpFailed);
6832 
6833   auto Index = std::make_unique<ModuleSummaryIndex>(/*HaveGVs=*/false);
6834   ModuleSummaryIndexBitcodeReader R(std::move(Stream), Strtab, *Index,
6835                                     ModuleIdentifier, 0);
6836 
6837   if (Error Err = R.parseModule())
6838     return std::move(Err);
6839 
6840   return std::move(Index);
6841 }
6842 
6843 static Expected<bool> getEnableSplitLTOUnitFlag(BitstreamCursor &Stream,
6844                                                 unsigned ID) {
6845   if (Error Err = Stream.EnterSubBlock(ID))
6846     return std::move(Err);
6847   SmallVector<uint64_t, 64> Record;
6848 
6849   while (true) {
6850     Expected<BitstreamEntry> MaybeEntry = Stream.advanceSkippingSubblocks();
6851     if (!MaybeEntry)
6852       return MaybeEntry.takeError();
6853     BitstreamEntry Entry = MaybeEntry.get();
6854 
6855     switch (Entry.Kind) {
6856     case BitstreamEntry::SubBlock: // Handled for us already.
6857     case BitstreamEntry::Error:
6858       return error("Malformed block");
6859     case BitstreamEntry::EndBlock:
6860       // If no flags record found, conservatively return true to mimic
6861       // behavior before this flag was added.
6862       return true;
6863     case BitstreamEntry::Record:
6864       // The interesting case.
6865       break;
6866     }
6867 
6868     // Look for the FS_FLAGS record.
6869     Record.clear();
6870     Expected<unsigned> MaybeBitCode = Stream.readRecord(Entry.ID, Record);
6871     if (!MaybeBitCode)
6872       return MaybeBitCode.takeError();
6873     switch (MaybeBitCode.get()) {
6874     default: // Default behavior: ignore.
6875       break;
6876     case bitc::FS_FLAGS: { // [flags]
6877       uint64_t Flags = Record[0];
6878       // Scan flags.
6879       assert(Flags <= 0x7f && "Unexpected bits in flag");
6880 
6881       return Flags & 0x8;
6882     }
6883     }
6884   }
6885   llvm_unreachable("Exit infinite loop");
6886 }
6887 
6888 // Check if the given bitcode buffer contains a global value summary block.
6889 Expected<BitcodeLTOInfo> BitcodeModule::getLTOInfo() {
6890   BitstreamCursor Stream(Buffer);
6891   if (Error JumpFailed = Stream.JumpToBit(ModuleBit))
6892     return std::move(JumpFailed);
6893 
6894   if (Error Err = Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
6895     return std::move(Err);
6896 
6897   while (true) {
6898     Expected<llvm::BitstreamEntry> MaybeEntry = Stream.advance();
6899     if (!MaybeEntry)
6900       return MaybeEntry.takeError();
6901     llvm::BitstreamEntry Entry = MaybeEntry.get();
6902 
6903     switch (Entry.Kind) {
6904     case BitstreamEntry::Error:
6905       return error("Malformed block");
6906     case BitstreamEntry::EndBlock:
6907       return BitcodeLTOInfo{/*IsThinLTO=*/false, /*HasSummary=*/false,
6908                             /*EnableSplitLTOUnit=*/false};
6909 
6910     case BitstreamEntry::SubBlock:
6911       if (Entry.ID == bitc::GLOBALVAL_SUMMARY_BLOCK_ID) {
6912         Expected<bool> EnableSplitLTOUnit =
6913             getEnableSplitLTOUnitFlag(Stream, Entry.ID);
6914         if (!EnableSplitLTOUnit)
6915           return EnableSplitLTOUnit.takeError();
6916         return BitcodeLTOInfo{/*IsThinLTO=*/true, /*HasSummary=*/true,
6917                               *EnableSplitLTOUnit};
6918       }
6919 
6920       if (Entry.ID == bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID) {
6921         Expected<bool> EnableSplitLTOUnit =
6922             getEnableSplitLTOUnitFlag(Stream, Entry.ID);
6923         if (!EnableSplitLTOUnit)
6924           return EnableSplitLTOUnit.takeError();
6925         return BitcodeLTOInfo{/*IsThinLTO=*/false, /*HasSummary=*/true,
6926                               *EnableSplitLTOUnit};
6927       }
6928 
6929       // Ignore other sub-blocks.
6930       if (Error Err = Stream.SkipBlock())
6931         return std::move(Err);
6932       continue;
6933 
6934     case BitstreamEntry::Record:
6935       if (Expected<unsigned> StreamFailed = Stream.skipRecord(Entry.ID))
6936         continue;
6937       else
6938         return StreamFailed.takeError();
6939     }
6940   }
6941 }
6942 
6943 static Expected<BitcodeModule> getSingleModule(MemoryBufferRef Buffer) {
6944   Expected<std::vector<BitcodeModule>> MsOrErr = getBitcodeModuleList(Buffer);
6945   if (!MsOrErr)
6946     return MsOrErr.takeError();
6947 
6948   if (MsOrErr->size() != 1)
6949     return error("Expected a single module");
6950 
6951   return (*MsOrErr)[0];
6952 }
6953 
6954 Expected<std::unique_ptr<Module>>
6955 llvm::getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,
6956                            bool ShouldLazyLoadMetadata, bool IsImporting) {
6957   Expected<BitcodeModule> BM = getSingleModule(Buffer);
6958   if (!BM)
6959     return BM.takeError();
6960 
6961   return BM->getLazyModule(Context, ShouldLazyLoadMetadata, IsImporting);
6962 }
6963 
6964 Expected<std::unique_ptr<Module>> llvm::getOwningLazyBitcodeModule(
6965     std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext &Context,
6966     bool ShouldLazyLoadMetadata, bool IsImporting) {
6967   auto MOrErr = getLazyBitcodeModule(*Buffer, Context, ShouldLazyLoadMetadata,
6968                                      IsImporting);
6969   if (MOrErr)
6970     (*MOrErr)->setOwnedMemoryBuffer(std::move(Buffer));
6971   return MOrErr;
6972 }
6973 
6974 Expected<std::unique_ptr<Module>>
6975 BitcodeModule::parseModule(LLVMContext &Context,
6976                            DataLayoutCallbackTy DataLayoutCallback) {
6977   return getModuleImpl(Context, true, false, false, DataLayoutCallback);
6978   // TODO: Restore the use-lists to the in-memory state when the bitcode was
6979   // written.  We must defer until the Module has been fully materialized.
6980 }
6981 
6982 Expected<std::unique_ptr<Module>>
6983 llvm::parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
6984                        DataLayoutCallbackTy DataLayoutCallback) {
6985   Expected<BitcodeModule> BM = getSingleModule(Buffer);
6986   if (!BM)
6987     return BM.takeError();
6988 
6989   return BM->parseModule(Context, DataLayoutCallback);
6990 }
6991 
6992 Expected<std::string> llvm::getBitcodeTargetTriple(MemoryBufferRef Buffer) {
6993   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
6994   if (!StreamOrErr)
6995     return StreamOrErr.takeError();
6996 
6997   return readTriple(*StreamOrErr);
6998 }
6999 
7000 Expected<bool> llvm::isBitcodeContainingObjCCategory(MemoryBufferRef Buffer) {
7001   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
7002   if (!StreamOrErr)
7003     return StreamOrErr.takeError();
7004 
7005   return hasObjCCategory(*StreamOrErr);
7006 }
7007 
7008 Expected<std::string> llvm::getBitcodeProducerString(MemoryBufferRef Buffer) {
7009   Expected<BitstreamCursor> StreamOrErr = initStream(Buffer);
7010   if (!StreamOrErr)
7011     return StreamOrErr.takeError();
7012 
7013   return readIdentificationCode(*StreamOrErr);
7014 }
7015 
7016 Error llvm::readModuleSummaryIndex(MemoryBufferRef Buffer,
7017                                    ModuleSummaryIndex &CombinedIndex,
7018                                    uint64_t ModuleId) {
7019   Expected<BitcodeModule> BM = getSingleModule(Buffer);
7020   if (!BM)
7021     return BM.takeError();
7022 
7023   return BM->readSummary(CombinedIndex, BM->getModuleIdentifier(), ModuleId);
7024 }
7025 
7026 Expected<std::unique_ptr<ModuleSummaryIndex>>
7027 llvm::getModuleSummaryIndex(MemoryBufferRef Buffer) {
7028   Expected<BitcodeModule> BM = getSingleModule(Buffer);
7029   if (!BM)
7030     return BM.takeError();
7031 
7032   return BM->getSummary();
7033 }
7034 
7035 Expected<BitcodeLTOInfo> llvm::getBitcodeLTOInfo(MemoryBufferRef Buffer) {
7036   Expected<BitcodeModule> BM = getSingleModule(Buffer);
7037   if (!BM)
7038     return BM.takeError();
7039 
7040   return BM->getLTOInfo();
7041 }
7042 
7043 Expected<std::unique_ptr<ModuleSummaryIndex>>
7044 llvm::getModuleSummaryIndexForFile(StringRef Path,
7045                                    bool IgnoreEmptyThinLTOIndexFile) {
7046   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
7047       MemoryBuffer::getFileOrSTDIN(Path);
7048   if (!FileOrErr)
7049     return errorCodeToError(FileOrErr.getError());
7050   if (IgnoreEmptyThinLTOIndexFile && !(*FileOrErr)->getBufferSize())
7051     return nullptr;
7052   return getModuleSummaryIndex(**FileOrErr);
7053 }
7054