xref: /freebsd/contrib/llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 770cf0a5f02dc8983a89c6568d741fbc25baa999)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
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 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SetVector.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/Analysis/MemoryProfileInfo.h"
27 #include "llvm/BinaryFormat/Dwarf.h"
28 #include "llvm/Bitcode/BitcodeCommon.h"
29 #include "llvm/Bitcode/BitcodeReader.h"
30 #include "llvm/Bitcode/LLVMBitCodes.h"
31 #include "llvm/Bitstream/BitCodes.h"
32 #include "llvm/Bitstream/BitstreamWriter.h"
33 #include "llvm/Config/llvm-config.h"
34 #include "llvm/IR/Attributes.h"
35 #include "llvm/IR/BasicBlock.h"
36 #include "llvm/IR/Comdat.h"
37 #include "llvm/IR/Constant.h"
38 #include "llvm/IR/ConstantRangeList.h"
39 #include "llvm/IR/Constants.h"
40 #include "llvm/IR/DebugInfoMetadata.h"
41 #include "llvm/IR/DebugLoc.h"
42 #include "llvm/IR/DerivedTypes.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/GlobalAlias.h"
45 #include "llvm/IR/GlobalIFunc.h"
46 #include "llvm/IR/GlobalObject.h"
47 #include "llvm/IR/GlobalValue.h"
48 #include "llvm/IR/GlobalVariable.h"
49 #include "llvm/IR/InlineAsm.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/LLVMContext.h"
54 #include "llvm/IR/Metadata.h"
55 #include "llvm/IR/Module.h"
56 #include "llvm/IR/ModuleSummaryIndex.h"
57 #include "llvm/IR/Operator.h"
58 #include "llvm/IR/Type.h"
59 #include "llvm/IR/UseListOrder.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/ValueSymbolTable.h"
62 #include "llvm/MC/StringTableBuilder.h"
63 #include "llvm/MC/TargetRegistry.h"
64 #include "llvm/Object/IRSymtab.h"
65 #include "llvm/ProfileData/MemProf.h"
66 #include "llvm/ProfileData/MemProfRadixTree.h"
67 #include "llvm/Support/AtomicOrdering.h"
68 #include "llvm/Support/Casting.h"
69 #include "llvm/Support/CommandLine.h"
70 #include "llvm/Support/Compiler.h"
71 #include "llvm/Support/Endian.h"
72 #include "llvm/Support/Error.h"
73 #include "llvm/Support/ErrorHandling.h"
74 #include "llvm/Support/MathExtras.h"
75 #include "llvm/Support/SHA1.h"
76 #include "llvm/Support/raw_ostream.h"
77 #include "llvm/TargetParser/Triple.h"
78 #include <algorithm>
79 #include <cassert>
80 #include <cstddef>
81 #include <cstdint>
82 #include <iterator>
83 #include <map>
84 #include <memory>
85 #include <optional>
86 #include <string>
87 #include <utility>
88 #include <vector>
89 
90 using namespace llvm;
91 using namespace llvm::memprof;
92 
93 static cl::opt<unsigned>
94     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
95                    cl::desc("Number of metadatas above which we emit an index "
96                             "to enable lazy-loading"));
97 static cl::opt<uint32_t> FlushThreshold(
98     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
99     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
100 
101 static cl::opt<bool> WriteRelBFToSummary(
102     "write-relbf-to-summary", cl::Hidden, cl::init(false),
103     cl::desc("Write relative block frequency to function summary "));
104 
105 // Since we only use the context information in the memprof summary records in
106 // the LTO backends to do assertion checking, save time and space by only
107 // serializing the context for non-NDEBUG builds.
108 // TODO: Currently this controls writing context of the allocation info records,
109 // which are larger and more expensive, but we should do this for the callsite
110 // records as well.
111 // FIXME: Convert to a const once this has undergone more sigificant testing.
112 static cl::opt<bool>
113     CombinedIndexMemProfContext("combined-index-memprof-context", cl::Hidden,
114 #ifdef NDEBUG
115                                 cl::init(false),
116 #else
117                                 cl::init(true),
118 #endif
119                                 cl::desc(""));
120 
121 namespace llvm {
122 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
123 }
124 
125 namespace {
126 
127 /// These are manifest constants used by the bitcode writer. They do not need to
128 /// be kept in sync with the reader, but need to be consistent within this file.
129 enum {
130   // VALUE_SYMTAB_BLOCK abbrev id's.
131   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
132   VST_ENTRY_7_ABBREV,
133   VST_ENTRY_6_ABBREV,
134   VST_BBENTRY_6_ABBREV,
135 
136   // CONSTANTS_BLOCK abbrev id's.
137   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
138   CONSTANTS_INTEGER_ABBREV,
139   CONSTANTS_CE_CAST_Abbrev,
140   CONSTANTS_NULL_Abbrev,
141 
142   // FUNCTION_BLOCK abbrev id's.
143   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
144   FUNCTION_INST_STORE_ABBREV,
145   FUNCTION_INST_UNOP_ABBREV,
146   FUNCTION_INST_UNOP_FLAGS_ABBREV,
147   FUNCTION_INST_BINOP_ABBREV,
148   FUNCTION_INST_BINOP_FLAGS_ABBREV,
149   FUNCTION_INST_CAST_ABBREV,
150   FUNCTION_INST_CAST_FLAGS_ABBREV,
151   FUNCTION_INST_RET_VOID_ABBREV,
152   FUNCTION_INST_RET_VAL_ABBREV,
153   FUNCTION_INST_BR_UNCOND_ABBREV,
154   FUNCTION_INST_BR_COND_ABBREV,
155   FUNCTION_INST_UNREACHABLE_ABBREV,
156   FUNCTION_INST_GEP_ABBREV,
157   FUNCTION_INST_CMP_ABBREV,
158   FUNCTION_INST_CMP_FLAGS_ABBREV,
159   FUNCTION_DEBUG_RECORD_VALUE_ABBREV,
160   FUNCTION_DEBUG_LOC_ABBREV,
161 };
162 
163 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
164 /// file type.
165 class BitcodeWriterBase {
166 protected:
167   /// The stream created and owned by the client.
168   BitstreamWriter &Stream;
169 
170   StringTableBuilder &StrtabBuilder;
171 
172 public:
173   /// Constructs a BitcodeWriterBase object that writes to the provided
174   /// \p Stream.
175   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
176       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
177 
178 protected:
179   void writeModuleVersion();
180 };
181 
182 void BitcodeWriterBase::writeModuleVersion() {
183   // VERSION: [version#]
184   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
185 }
186 
187 /// Base class to manage the module bitcode writing, currently subclassed for
188 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
189 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
190 protected:
191   /// The Module to write to bitcode.
192   const Module &M;
193 
194   /// Enumerates ids for all values in the module.
195   ValueEnumerator VE;
196 
197   /// Optional per-module index to write for ThinLTO.
198   const ModuleSummaryIndex *Index;
199 
200   /// Map that holds the correspondence between GUIDs in the summary index,
201   /// that came from indirect call profiles, and a value id generated by this
202   /// class to use in the VST and summary block records.
203   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
204 
205   /// Tracks the last value id recorded in the GUIDToValueMap.
206   unsigned GlobalValueId;
207 
208   /// Saves the offset of the VSTOffset record that must eventually be
209   /// backpatched with the offset of the actual VST.
210   uint64_t VSTOffsetPlaceholder = 0;
211 
212 public:
213   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
214   /// writing to the provided \p Buffer.
215   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
216                           BitstreamWriter &Stream,
217                           bool ShouldPreserveUseListOrder,
218                           const ModuleSummaryIndex *Index)
219       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
220         VE(M, ShouldPreserveUseListOrder), Index(Index) {
221     // Assign ValueIds to any callee values in the index that came from
222     // indirect call profiles and were recorded as a GUID not a Value*
223     // (which would have been assigned an ID by the ValueEnumerator).
224     // The starting ValueId is just after the number of values in the
225     // ValueEnumerator, so that they can be emitted in the VST.
226     GlobalValueId = VE.getValues().size();
227     if (!Index)
228       return;
229     for (const auto &GUIDSummaryLists : *Index)
230       // Examine all summaries for this GUID.
231       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
232         if (auto FS = dyn_cast<FunctionSummary>(Summary.get())) {
233           // For each call in the function summary, see if the call
234           // is to a GUID (which means it is for an indirect call,
235           // otherwise we would have a Value for it). If so, synthesize
236           // a value id.
237           for (auto &CallEdge : FS->calls())
238             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
239               assignValueId(CallEdge.first.getGUID());
240 
241           // For each referenced variables in the function summary, see if the
242           // variable is represented by a GUID (as opposed to a symbol to
243           // declarations or definitions in the module). If so, synthesize a
244           // value id.
245           for (auto &RefEdge : FS->refs())
246             if (!RefEdge.haveGVs() || !RefEdge.getValue())
247               assignValueId(RefEdge.getGUID());
248         }
249   }
250 
251 protected:
252   void writePerModuleGlobalValueSummary();
253 
254 private:
255   void writePerModuleFunctionSummaryRecord(
256       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
257       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
258       unsigned CallsiteAbbrev, unsigned AllocAbbrev, unsigned ContextIdAbbvId,
259       const Function &F, DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
260       CallStackId &CallStackCount);
261   void writeModuleLevelReferences(const GlobalVariable &V,
262                                   SmallVector<uint64_t, 64> &NameVals,
263                                   unsigned FSModRefsAbbrev,
264                                   unsigned FSModVTableRefsAbbrev);
265 
266   void assignValueId(GlobalValue::GUID ValGUID) {
267     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
268   }
269 
270   unsigned getValueId(GlobalValue::GUID ValGUID) {
271     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
272     // Expect that any GUID value had a value Id assigned by an
273     // earlier call to assignValueId.
274     assert(VMI != GUIDToValueIdMap.end() &&
275            "GUID does not have assigned value Id");
276     return VMI->second;
277   }
278 
279   // Helper to get the valueId for the type of value recorded in VI.
280   unsigned getValueId(ValueInfo VI) {
281     if (!VI.haveGVs() || !VI.getValue())
282       return getValueId(VI.getGUID());
283     return VE.getValueID(VI.getValue());
284   }
285 
286   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
287 };
288 
289 /// Class to manage the bitcode writing for a module.
290 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
291   /// True if a module hash record should be written.
292   bool GenerateHash;
293 
294   /// If non-null, when GenerateHash is true, the resulting hash is written
295   /// into ModHash.
296   ModuleHash *ModHash;
297 
298   SHA1 Hasher;
299 
300   /// The start bit of the identification block.
301   uint64_t BitcodeStartBit;
302 
303 public:
304   /// Constructs a ModuleBitcodeWriter object for the given Module,
305   /// writing to the provided \p Buffer.
306   ModuleBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
307                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
308                       const ModuleSummaryIndex *Index, bool GenerateHash,
309                       ModuleHash *ModHash = nullptr)
310       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
311                                 ShouldPreserveUseListOrder, Index),
312         GenerateHash(GenerateHash), ModHash(ModHash),
313         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
314 
315   /// Emit the current module to the bitstream.
316   void write();
317 
318 private:
319   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
320 
321   size_t addToStrtab(StringRef Str);
322 
323   void writeAttributeGroupTable();
324   void writeAttributeTable();
325   void writeTypeTable();
326   void writeComdats();
327   void writeValueSymbolTableForwardDecl();
328   void writeModuleInfo();
329   void writeValueAsMetadata(const ValueAsMetadata *MD,
330                             SmallVectorImpl<uint64_t> &Record);
331   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
332                     unsigned Abbrev);
333   unsigned createDILocationAbbrev();
334   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
335                        unsigned &Abbrev);
336   unsigned createGenericDINodeAbbrev();
337   void writeGenericDINode(const GenericDINode *N,
338                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
339   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
340                        unsigned Abbrev);
341   void writeDIGenericSubrange(const DIGenericSubrange *N,
342                               SmallVectorImpl<uint64_t> &Record,
343                               unsigned Abbrev);
344   void writeDIEnumerator(const DIEnumerator *N,
345                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
346   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
347                         unsigned Abbrev);
348   void writeDIFixedPointType(const DIFixedPointType *N,
349                              SmallVectorImpl<uint64_t> &Record,
350                              unsigned Abbrev);
351   void writeDIStringType(const DIStringType *N,
352                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
353   void writeDIDerivedType(const DIDerivedType *N,
354                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDISubrangeType(const DISubrangeType *N,
356                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDICompositeType(const DICompositeType *N,
358                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
359   void writeDISubroutineType(const DISubroutineType *N,
360                              SmallVectorImpl<uint64_t> &Record,
361                              unsigned Abbrev);
362   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
363                    unsigned Abbrev);
364   void writeDICompileUnit(const DICompileUnit *N,
365                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
366   void writeDISubprogram(const DISubprogram *N,
367                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
368   void writeDILexicalBlock(const DILexicalBlock *N,
369                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
370   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
371                                SmallVectorImpl<uint64_t> &Record,
372                                unsigned Abbrev);
373   void writeDICommonBlock(const DICommonBlock *N,
374                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
375   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
376                         unsigned Abbrev);
377   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
378                     unsigned Abbrev);
379   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
380                         unsigned Abbrev);
381   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record);
382   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
383                      unsigned Abbrev);
384   void writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
385                        unsigned Abbrev);
386   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
387                                     SmallVectorImpl<uint64_t> &Record,
388                                     unsigned Abbrev);
389   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
390                                      SmallVectorImpl<uint64_t> &Record,
391                                      unsigned Abbrev);
392   void writeDIGlobalVariable(const DIGlobalVariable *N,
393                              SmallVectorImpl<uint64_t> &Record,
394                              unsigned Abbrev);
395   void writeDILocalVariable(const DILocalVariable *N,
396                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
397   void writeDILabel(const DILabel *N,
398                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
399   void writeDIExpression(const DIExpression *N,
400                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
401   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
402                                        SmallVectorImpl<uint64_t> &Record,
403                                        unsigned Abbrev);
404   void writeDIObjCProperty(const DIObjCProperty *N,
405                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
406   void writeDIImportedEntity(const DIImportedEntity *N,
407                              SmallVectorImpl<uint64_t> &Record,
408                              unsigned Abbrev);
409   unsigned createNamedMetadataAbbrev();
410   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
411   unsigned createMetadataStringsAbbrev();
412   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
413                             SmallVectorImpl<uint64_t> &Record);
414   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
415                             SmallVectorImpl<uint64_t> &Record,
416                             std::vector<unsigned> *MDAbbrevs = nullptr,
417                             std::vector<uint64_t> *IndexPos = nullptr);
418   void writeModuleMetadata();
419   void writeFunctionMetadata(const Function &F);
420   void writeFunctionMetadataAttachment(const Function &F);
421   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
422                                     const GlobalObject &GO);
423   void writeModuleMetadataKinds();
424   void writeOperandBundleTags();
425   void writeSyncScopeNames();
426   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
427   void writeModuleConstants();
428   bool pushValueAndType(const Value *V, unsigned InstID,
429                         SmallVectorImpl<unsigned> &Vals);
430   bool pushValueOrMetadata(const Value *V, unsigned InstID,
431                            SmallVectorImpl<unsigned> &Vals);
432   void writeOperandBundles(const CallBase &CB, unsigned InstID);
433   void pushValue(const Value *V, unsigned InstID,
434                  SmallVectorImpl<unsigned> &Vals);
435   void pushValueSigned(const Value *V, unsigned InstID,
436                        SmallVectorImpl<uint64_t> &Vals);
437   void writeInstruction(const Instruction &I, unsigned InstID,
438                         SmallVectorImpl<unsigned> &Vals);
439   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
440   void writeGlobalValueSymbolTable(
441       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
442   void writeUseList(UseListOrder &&Order);
443   void writeUseListBlock(const Function *F);
444   void
445   writeFunction(const Function &F,
446                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
447   void writeBlockInfo();
448   void writeModuleHash(StringRef View);
449 
450   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
451     return unsigned(SSID);
452   }
453 
454   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
455 };
456 
457 /// Class to manage the bitcode writing for a combined index.
458 class IndexBitcodeWriter : public BitcodeWriterBase {
459   /// The combined index to write to bitcode.
460   const ModuleSummaryIndex &Index;
461 
462   /// When writing combined summaries, provides the set of global value
463   /// summaries for which the value (function, function alias, etc) should be
464   /// imported as a declaration.
465   const GVSummaryPtrSet *DecSummaries = nullptr;
466 
467   /// When writing a subset of the index for distributed backends, client
468   /// provides a map of modules to the corresponding GUIDs/summaries to write.
469   const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex;
470 
471   /// Map that holds the correspondence between the GUID used in the combined
472   /// index and a value id generated by this class to use in references.
473   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
474 
475   // The stack ids used by this index, which will be a subset of those in
476   // the full index in the case of distributed indexes.
477   std::vector<uint64_t> StackIds;
478 
479   // Keep a map of the stack id indices used by records being written for this
480   // index to the index of the corresponding stack id in the above StackIds
481   // vector. Ensures we write each referenced stack id once.
482   DenseMap<unsigned, unsigned> StackIdIndicesToIndex;
483 
484   /// Tracks the last value id recorded in the GUIDToValueMap.
485   unsigned GlobalValueId = 0;
486 
487   /// Tracks the assignment of module paths in the module path string table to
488   /// an id assigned for use in summary references to the module path.
489   DenseMap<StringRef, uint64_t> ModuleIdMap;
490 
491 public:
492   /// Constructs a IndexBitcodeWriter object for the given combined index,
493   /// writing to the provided \p Buffer. When writing a subset of the index
494   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
495   /// If provided, \p DecSummaries specifies the set of summaries for which
496   /// the corresponding functions or aliased functions should be imported as a
497   /// declaration (but not definition) for each module.
498   IndexBitcodeWriter(
499       BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
500       const ModuleSummaryIndex &Index,
501       const GVSummaryPtrSet *DecSummaries = nullptr,
502       const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex = nullptr)
503       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
504         DecSummaries(DecSummaries),
505         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
506 
507     // See if the StackIdIndex was already added to the StackId map and
508     // vector. If not, record it.
509     auto RecordStackIdReference = [&](unsigned StackIdIndex) {
510       // If the StackIdIndex is not yet in the map, the below insert ensures
511       // that it will point to the new StackIds vector entry we push to just
512       // below.
513       auto Inserted =
514           StackIdIndicesToIndex.insert({StackIdIndex, StackIds.size()});
515       if (Inserted.second)
516         StackIds.push_back(Index.getStackIdAtIndex(StackIdIndex));
517     };
518 
519     // Assign unique value ids to all summaries to be written, for use
520     // in writing out the call graph edges. Save the mapping from GUID
521     // to the new global value id to use when writing those edges, which
522     // are currently saved in the index in terms of GUID.
523     forEachSummary([&](GVInfo I, bool IsAliasee) {
524       GUIDToValueIdMap[I.first] = ++GlobalValueId;
525       // If this is invoked for an aliasee, we want to record the above mapping,
526       // but not the information needed for its summary entry (if the aliasee is
527       // to be imported, we will invoke this separately with IsAliasee=false).
528       if (IsAliasee)
529         return;
530       auto *FS = dyn_cast<FunctionSummary>(I.second);
531       if (!FS)
532         return;
533       // Record all stack id indices actually used in the summary entries being
534       // written, so that we can compact them in the case of distributed ThinLTO
535       // indexes.
536       for (auto &CI : FS->callsites()) {
537         // If the stack id list is empty, this callsite info was synthesized for
538         // a missing tail call frame. Ensure that the callee's GUID gets a value
539         // id. Normally we only generate these for defined summaries, which in
540         // the case of distributed ThinLTO is only the functions already defined
541         // in the module or that we want to import. We don't bother to include
542         // all the callee symbols as they aren't normally needed in the backend.
543         // However, for the synthesized callsite infos we do need the callee
544         // GUID in the backend so that we can correlate the identified callee
545         // with this callsite info (which for non-tail calls is done by the
546         // ordering of the callsite infos and verified via stack ids).
547         if (CI.StackIdIndices.empty()) {
548           GUIDToValueIdMap[CI.Callee.getGUID()] = ++GlobalValueId;
549           continue;
550         }
551         for (auto Idx : CI.StackIdIndices)
552           RecordStackIdReference(Idx);
553       }
554       if (CombinedIndexMemProfContext) {
555         for (auto &AI : FS->allocs())
556           for (auto &MIB : AI.MIBs)
557             for (auto Idx : MIB.StackIdIndices)
558               RecordStackIdReference(Idx);
559       }
560     });
561   }
562 
563   /// The below iterator returns the GUID and associated summary.
564   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
565 
566   /// Calls the callback for each value GUID and summary to be written to
567   /// bitcode. This hides the details of whether they are being pulled from the
568   /// entire index or just those in a provided ModuleToSummariesForIndex map.
569   template<typename Functor>
570   void forEachSummary(Functor Callback) {
571     if (ModuleToSummariesForIndex) {
572       for (auto &M : *ModuleToSummariesForIndex)
573         for (auto &Summary : M.second) {
574           Callback(Summary, false);
575           // Ensure aliasee is handled, e.g. for assigning a valueId,
576           // even if we are not importing the aliasee directly (the
577           // imported alias will contain a copy of aliasee).
578           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
579             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
580         }
581     } else {
582       for (auto &Summaries : Index)
583         for (auto &Summary : Summaries.second.SummaryList)
584           Callback({Summaries.first, Summary.get()}, false);
585     }
586   }
587 
588   /// Calls the callback for each entry in the modulePaths StringMap that
589   /// should be written to the module path string table. This hides the details
590   /// of whether they are being pulled from the entire index or just those in a
591   /// provided ModuleToSummariesForIndex map.
592   template <typename Functor> void forEachModule(Functor Callback) {
593     if (ModuleToSummariesForIndex) {
594       for (const auto &M : *ModuleToSummariesForIndex) {
595         const auto &MPI = Index.modulePaths().find(M.first);
596         if (MPI == Index.modulePaths().end()) {
597           // This should only happen if the bitcode file was empty, in which
598           // case we shouldn't be importing (the ModuleToSummariesForIndex
599           // would only include the module we are writing and index for).
600           assert(ModuleToSummariesForIndex->size() == 1);
601           continue;
602         }
603         Callback(*MPI);
604       }
605     } else {
606       // Since StringMap iteration order isn't guaranteed, order by path string
607       // first.
608       // FIXME: Make this a vector of StringMapEntry instead to avoid the later
609       // map lookup.
610       std::vector<StringRef> ModulePaths;
611       for (auto &[ModPath, _] : Index.modulePaths())
612         ModulePaths.push_back(ModPath);
613       llvm::sort(ModulePaths.begin(), ModulePaths.end());
614       for (auto &ModPath : ModulePaths)
615         Callback(*Index.modulePaths().find(ModPath));
616     }
617   }
618 
619   /// Main entry point for writing a combined index to bitcode.
620   void write();
621 
622 private:
623   void writeModStrings();
624   void writeCombinedGlobalValueSummary();
625 
626   std::optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
627     auto VMI = GUIDToValueIdMap.find(ValGUID);
628     if (VMI == GUIDToValueIdMap.end())
629       return std::nullopt;
630     return VMI->second;
631   }
632 
633   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
634 };
635 
636 } // end anonymous namespace
637 
638 static unsigned getEncodedCastOpcode(unsigned Opcode) {
639   switch (Opcode) {
640   default: llvm_unreachable("Unknown cast instruction!");
641   case Instruction::Trunc   : return bitc::CAST_TRUNC;
642   case Instruction::ZExt    : return bitc::CAST_ZEXT;
643   case Instruction::SExt    : return bitc::CAST_SEXT;
644   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
645   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
646   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
647   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
648   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
649   case Instruction::FPExt   : return bitc::CAST_FPEXT;
650   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
651   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
652   case Instruction::BitCast : return bitc::CAST_BITCAST;
653   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
654   }
655 }
656 
657 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
658   switch (Opcode) {
659   default: llvm_unreachable("Unknown binary instruction!");
660   case Instruction::FNeg: return bitc::UNOP_FNEG;
661   }
662 }
663 
664 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
665   switch (Opcode) {
666   default: llvm_unreachable("Unknown binary instruction!");
667   case Instruction::Add:
668   case Instruction::FAdd: return bitc::BINOP_ADD;
669   case Instruction::Sub:
670   case Instruction::FSub: return bitc::BINOP_SUB;
671   case Instruction::Mul:
672   case Instruction::FMul: return bitc::BINOP_MUL;
673   case Instruction::UDiv: return bitc::BINOP_UDIV;
674   case Instruction::FDiv:
675   case Instruction::SDiv: return bitc::BINOP_SDIV;
676   case Instruction::URem: return bitc::BINOP_UREM;
677   case Instruction::FRem:
678   case Instruction::SRem: return bitc::BINOP_SREM;
679   case Instruction::Shl:  return bitc::BINOP_SHL;
680   case Instruction::LShr: return bitc::BINOP_LSHR;
681   case Instruction::AShr: return bitc::BINOP_ASHR;
682   case Instruction::And:  return bitc::BINOP_AND;
683   case Instruction::Or:   return bitc::BINOP_OR;
684   case Instruction::Xor:  return bitc::BINOP_XOR;
685   }
686 }
687 
688 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
689   switch (Op) {
690   default: llvm_unreachable("Unknown RMW operation!");
691   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
692   case AtomicRMWInst::Add: return bitc::RMW_ADD;
693   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
694   case AtomicRMWInst::And: return bitc::RMW_AND;
695   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
696   case AtomicRMWInst::Or: return bitc::RMW_OR;
697   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
698   case AtomicRMWInst::Max: return bitc::RMW_MAX;
699   case AtomicRMWInst::Min: return bitc::RMW_MIN;
700   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
701   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
702   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
703   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
704   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
705   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
706   case AtomicRMWInst::FMaximum:
707     return bitc::RMW_FMAXIMUM;
708   case AtomicRMWInst::FMinimum:
709     return bitc::RMW_FMINIMUM;
710   case AtomicRMWInst::UIncWrap:
711     return bitc::RMW_UINC_WRAP;
712   case AtomicRMWInst::UDecWrap:
713     return bitc::RMW_UDEC_WRAP;
714   case AtomicRMWInst::USubCond:
715     return bitc::RMW_USUB_COND;
716   case AtomicRMWInst::USubSat:
717     return bitc::RMW_USUB_SAT;
718   }
719 }
720 
721 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
722   switch (Ordering) {
723   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
724   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
725   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
726   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
727   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
728   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
729   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
730   }
731   llvm_unreachable("Invalid ordering");
732 }
733 
734 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
735                               StringRef Str, unsigned AbbrevToUse) {
736   SmallVector<unsigned, 64> Vals;
737 
738   // Code: [strchar x N]
739   for (char C : Str) {
740     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
741       AbbrevToUse = 0;
742     Vals.push_back(C);
743   }
744 
745   // Emit the finished record.
746   Stream.EmitRecord(Code, Vals, AbbrevToUse);
747 }
748 
749 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
750   switch (Kind) {
751   case Attribute::Alignment:
752     return bitc::ATTR_KIND_ALIGNMENT;
753   case Attribute::AllocAlign:
754     return bitc::ATTR_KIND_ALLOC_ALIGN;
755   case Attribute::AllocSize:
756     return bitc::ATTR_KIND_ALLOC_SIZE;
757   case Attribute::AlwaysInline:
758     return bitc::ATTR_KIND_ALWAYS_INLINE;
759   case Attribute::Builtin:
760     return bitc::ATTR_KIND_BUILTIN;
761   case Attribute::ByVal:
762     return bitc::ATTR_KIND_BY_VAL;
763   case Attribute::Convergent:
764     return bitc::ATTR_KIND_CONVERGENT;
765   case Attribute::InAlloca:
766     return bitc::ATTR_KIND_IN_ALLOCA;
767   case Attribute::Cold:
768     return bitc::ATTR_KIND_COLD;
769   case Attribute::DisableSanitizerInstrumentation:
770     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
771   case Attribute::FnRetThunkExtern:
772     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
773   case Attribute::Hot:
774     return bitc::ATTR_KIND_HOT;
775   case Attribute::ElementType:
776     return bitc::ATTR_KIND_ELEMENTTYPE;
777   case Attribute::HybridPatchable:
778     return bitc::ATTR_KIND_HYBRID_PATCHABLE;
779   case Attribute::InlineHint:
780     return bitc::ATTR_KIND_INLINE_HINT;
781   case Attribute::InReg:
782     return bitc::ATTR_KIND_IN_REG;
783   case Attribute::JumpTable:
784     return bitc::ATTR_KIND_JUMP_TABLE;
785   case Attribute::MinSize:
786     return bitc::ATTR_KIND_MIN_SIZE;
787   case Attribute::AllocatedPointer:
788     return bitc::ATTR_KIND_ALLOCATED_POINTER;
789   case Attribute::AllocKind:
790     return bitc::ATTR_KIND_ALLOC_KIND;
791   case Attribute::Memory:
792     return bitc::ATTR_KIND_MEMORY;
793   case Attribute::NoFPClass:
794     return bitc::ATTR_KIND_NOFPCLASS;
795   case Attribute::Naked:
796     return bitc::ATTR_KIND_NAKED;
797   case Attribute::Nest:
798     return bitc::ATTR_KIND_NEST;
799   case Attribute::NoAlias:
800     return bitc::ATTR_KIND_NO_ALIAS;
801   case Attribute::NoBuiltin:
802     return bitc::ATTR_KIND_NO_BUILTIN;
803   case Attribute::NoCallback:
804     return bitc::ATTR_KIND_NO_CALLBACK;
805   case Attribute::NoDivergenceSource:
806     return bitc::ATTR_KIND_NO_DIVERGENCE_SOURCE;
807   case Attribute::NoDuplicate:
808     return bitc::ATTR_KIND_NO_DUPLICATE;
809   case Attribute::NoFree:
810     return bitc::ATTR_KIND_NOFREE;
811   case Attribute::NoImplicitFloat:
812     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
813   case Attribute::NoInline:
814     return bitc::ATTR_KIND_NO_INLINE;
815   case Attribute::NoRecurse:
816     return bitc::ATTR_KIND_NO_RECURSE;
817   case Attribute::NoMerge:
818     return bitc::ATTR_KIND_NO_MERGE;
819   case Attribute::NonLazyBind:
820     return bitc::ATTR_KIND_NON_LAZY_BIND;
821   case Attribute::NonNull:
822     return bitc::ATTR_KIND_NON_NULL;
823   case Attribute::Dereferenceable:
824     return bitc::ATTR_KIND_DEREFERENCEABLE;
825   case Attribute::DereferenceableOrNull:
826     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
827   case Attribute::NoRedZone:
828     return bitc::ATTR_KIND_NO_RED_ZONE;
829   case Attribute::NoReturn:
830     return bitc::ATTR_KIND_NO_RETURN;
831   case Attribute::NoSync:
832     return bitc::ATTR_KIND_NOSYNC;
833   case Attribute::NoCfCheck:
834     return bitc::ATTR_KIND_NOCF_CHECK;
835   case Attribute::NoProfile:
836     return bitc::ATTR_KIND_NO_PROFILE;
837   case Attribute::SkipProfile:
838     return bitc::ATTR_KIND_SKIP_PROFILE;
839   case Attribute::NoUnwind:
840     return bitc::ATTR_KIND_NO_UNWIND;
841   case Attribute::NoSanitizeBounds:
842     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
843   case Attribute::NoSanitizeCoverage:
844     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
845   case Attribute::NullPointerIsValid:
846     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
847   case Attribute::OptimizeForDebugging:
848     return bitc::ATTR_KIND_OPTIMIZE_FOR_DEBUGGING;
849   case Attribute::OptForFuzzing:
850     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
851   case Attribute::OptimizeForSize:
852     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
853   case Attribute::OptimizeNone:
854     return bitc::ATTR_KIND_OPTIMIZE_NONE;
855   case Attribute::ReadNone:
856     return bitc::ATTR_KIND_READ_NONE;
857   case Attribute::ReadOnly:
858     return bitc::ATTR_KIND_READ_ONLY;
859   case Attribute::Returned:
860     return bitc::ATTR_KIND_RETURNED;
861   case Attribute::ReturnsTwice:
862     return bitc::ATTR_KIND_RETURNS_TWICE;
863   case Attribute::SExt:
864     return bitc::ATTR_KIND_S_EXT;
865   case Attribute::Speculatable:
866     return bitc::ATTR_KIND_SPECULATABLE;
867   case Attribute::StackAlignment:
868     return bitc::ATTR_KIND_STACK_ALIGNMENT;
869   case Attribute::StackProtect:
870     return bitc::ATTR_KIND_STACK_PROTECT;
871   case Attribute::StackProtectReq:
872     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
873   case Attribute::StackProtectStrong:
874     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
875   case Attribute::SafeStack:
876     return bitc::ATTR_KIND_SAFESTACK;
877   case Attribute::ShadowCallStack:
878     return bitc::ATTR_KIND_SHADOWCALLSTACK;
879   case Attribute::StrictFP:
880     return bitc::ATTR_KIND_STRICT_FP;
881   case Attribute::StructRet:
882     return bitc::ATTR_KIND_STRUCT_RET;
883   case Attribute::SanitizeAddress:
884     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
885   case Attribute::SanitizeHWAddress:
886     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
887   case Attribute::SanitizeThread:
888     return bitc::ATTR_KIND_SANITIZE_THREAD;
889   case Attribute::SanitizeType:
890     return bitc::ATTR_KIND_SANITIZE_TYPE;
891   case Attribute::SanitizeMemory:
892     return bitc::ATTR_KIND_SANITIZE_MEMORY;
893   case Attribute::SanitizeNumericalStability:
894     return bitc::ATTR_KIND_SANITIZE_NUMERICAL_STABILITY;
895   case Attribute::SanitizeRealtime:
896     return bitc::ATTR_KIND_SANITIZE_REALTIME;
897   case Attribute::SanitizeRealtimeBlocking:
898     return bitc::ATTR_KIND_SANITIZE_REALTIME_BLOCKING;
899   case Attribute::SpeculativeLoadHardening:
900     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
901   case Attribute::SwiftError:
902     return bitc::ATTR_KIND_SWIFT_ERROR;
903   case Attribute::SwiftSelf:
904     return bitc::ATTR_KIND_SWIFT_SELF;
905   case Attribute::SwiftAsync:
906     return bitc::ATTR_KIND_SWIFT_ASYNC;
907   case Attribute::UWTable:
908     return bitc::ATTR_KIND_UW_TABLE;
909   case Attribute::VScaleRange:
910     return bitc::ATTR_KIND_VSCALE_RANGE;
911   case Attribute::WillReturn:
912     return bitc::ATTR_KIND_WILLRETURN;
913   case Attribute::WriteOnly:
914     return bitc::ATTR_KIND_WRITEONLY;
915   case Attribute::ZExt:
916     return bitc::ATTR_KIND_Z_EXT;
917   case Attribute::ImmArg:
918     return bitc::ATTR_KIND_IMMARG;
919   case Attribute::SanitizeMemTag:
920     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
921   case Attribute::Preallocated:
922     return bitc::ATTR_KIND_PREALLOCATED;
923   case Attribute::NoUndef:
924     return bitc::ATTR_KIND_NOUNDEF;
925   case Attribute::ByRef:
926     return bitc::ATTR_KIND_BYREF;
927   case Attribute::MustProgress:
928     return bitc::ATTR_KIND_MUSTPROGRESS;
929   case Attribute::PresplitCoroutine:
930     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
931   case Attribute::Writable:
932     return bitc::ATTR_KIND_WRITABLE;
933   case Attribute::CoroDestroyOnlyWhenComplete:
934     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
935   case Attribute::CoroElideSafe:
936     return bitc::ATTR_KIND_CORO_ELIDE_SAFE;
937   case Attribute::DeadOnUnwind:
938     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
939   case Attribute::Range:
940     return bitc::ATTR_KIND_RANGE;
941   case Attribute::Initializes:
942     return bitc::ATTR_KIND_INITIALIZES;
943   case Attribute::NoExt:
944     return bitc::ATTR_KIND_NO_EXT;
945   case Attribute::Captures:
946     return bitc::ATTR_KIND_CAPTURES;
947   case Attribute::DeadOnReturn:
948     return bitc::ATTR_KIND_DEAD_ON_RETURN;
949   case Attribute::EndAttrKinds:
950     llvm_unreachable("Can not encode end-attribute kinds marker.");
951   case Attribute::None:
952     llvm_unreachable("Can not encode none-attribute.");
953   case Attribute::EmptyKey:
954   case Attribute::TombstoneKey:
955     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
956   }
957 
958   llvm_unreachable("Trying to encode unknown attribute");
959 }
960 
961 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
962   if ((int64_t)V >= 0)
963     Vals.push_back(V << 1);
964   else
965     Vals.push_back((-V << 1) | 1);
966 }
967 
968 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
969   // We have an arbitrary precision integer value to write whose
970   // bit width is > 64. However, in canonical unsigned integer
971   // format it is likely that the high bits are going to be zero.
972   // So, we only write the number of active words.
973   unsigned NumWords = A.getActiveWords();
974   const uint64_t *RawData = A.getRawData();
975   for (unsigned i = 0; i < NumWords; i++)
976     emitSignedInt64(Vals, RawData[i]);
977 }
978 
979 static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
980                               const ConstantRange &CR, bool EmitBitWidth) {
981   unsigned BitWidth = CR.getBitWidth();
982   if (EmitBitWidth)
983     Record.push_back(BitWidth);
984   if (BitWidth > 64) {
985     Record.push_back(CR.getLower().getActiveWords() |
986                      (uint64_t(CR.getUpper().getActiveWords()) << 32));
987     emitWideAPInt(Record, CR.getLower());
988     emitWideAPInt(Record, CR.getUpper());
989   } else {
990     emitSignedInt64(Record, CR.getLower().getSExtValue());
991     emitSignedInt64(Record, CR.getUpper().getSExtValue());
992   }
993 }
994 
995 void ModuleBitcodeWriter::writeAttributeGroupTable() {
996   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
997       VE.getAttributeGroups();
998   if (AttrGrps.empty()) return;
999 
1000   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
1001 
1002   SmallVector<uint64_t, 64> Record;
1003   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
1004     unsigned AttrListIndex = Pair.first;
1005     AttributeSet AS = Pair.second;
1006     Record.push_back(VE.getAttributeGroupID(Pair));
1007     Record.push_back(AttrListIndex);
1008 
1009     for (Attribute Attr : AS) {
1010       if (Attr.isEnumAttribute()) {
1011         Record.push_back(0);
1012         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
1013       } else if (Attr.isIntAttribute()) {
1014         Record.push_back(1);
1015         Attribute::AttrKind Kind = Attr.getKindAsEnum();
1016         Record.push_back(getAttrKindEncoding(Kind));
1017         if (Kind == Attribute::Memory) {
1018           // Version field for upgrading old memory effects.
1019           const uint64_t Version = 1;
1020           Record.push_back((Version << 56) | Attr.getValueAsInt());
1021         } else {
1022           Record.push_back(Attr.getValueAsInt());
1023         }
1024       } else if (Attr.isStringAttribute()) {
1025         StringRef Kind = Attr.getKindAsString();
1026         StringRef Val = Attr.getValueAsString();
1027 
1028         Record.push_back(Val.empty() ? 3 : 4);
1029         Record.append(Kind.begin(), Kind.end());
1030         Record.push_back(0);
1031         if (!Val.empty()) {
1032           Record.append(Val.begin(), Val.end());
1033           Record.push_back(0);
1034         }
1035       } else if (Attr.isTypeAttribute()) {
1036         Type *Ty = Attr.getValueAsType();
1037         Record.push_back(Ty ? 6 : 5);
1038         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
1039         if (Ty)
1040           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
1041       } else if (Attr.isConstantRangeAttribute()) {
1042         Record.push_back(7);
1043         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
1044         emitConstantRange(Record, Attr.getValueAsConstantRange(),
1045                           /*EmitBitWidth=*/true);
1046       } else {
1047         assert(Attr.isConstantRangeListAttribute());
1048         Record.push_back(8);
1049         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
1050         ArrayRef<ConstantRange> Val = Attr.getValueAsConstantRangeList();
1051         Record.push_back(Val.size());
1052         Record.push_back(Val[0].getBitWidth());
1053         for (auto &CR : Val)
1054           emitConstantRange(Record, CR, /*EmitBitWidth=*/false);
1055       }
1056     }
1057 
1058     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
1059     Record.clear();
1060   }
1061 
1062   Stream.ExitBlock();
1063 }
1064 
1065 void ModuleBitcodeWriter::writeAttributeTable() {
1066   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
1067   if (Attrs.empty()) return;
1068 
1069   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
1070 
1071   SmallVector<uint64_t, 64> Record;
1072   for (const AttributeList &AL : Attrs) {
1073     for (unsigned i : AL.indexes()) {
1074       AttributeSet AS = AL.getAttributes(i);
1075       if (AS.hasAttributes())
1076         Record.push_back(VE.getAttributeGroupID({i, AS}));
1077     }
1078 
1079     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
1080     Record.clear();
1081   }
1082 
1083   Stream.ExitBlock();
1084 }
1085 
1086 /// WriteTypeTable - Write out the type table for a module.
1087 void ModuleBitcodeWriter::writeTypeTable() {
1088   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
1089 
1090   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
1091   SmallVector<uint64_t, 64> TypeVals;
1092 
1093   uint64_t NumBits = VE.computeBitsRequiredForTypeIndices();
1094 
1095   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
1096   auto Abbv = std::make_shared<BitCodeAbbrev>();
1097   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
1098   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
1099   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1100 
1101   // Abbrev for TYPE_CODE_FUNCTION.
1102   Abbv = std::make_shared<BitCodeAbbrev>();
1103   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
1104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
1105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1107   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1108 
1109   // Abbrev for TYPE_CODE_STRUCT_ANON.
1110   Abbv = std::make_shared<BitCodeAbbrev>();
1111   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
1112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1115   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1116 
1117   // Abbrev for TYPE_CODE_STRUCT_NAME.
1118   Abbv = std::make_shared<BitCodeAbbrev>();
1119   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
1120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1122   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1123 
1124   // Abbrev for TYPE_CODE_STRUCT_NAMED.
1125   Abbv = std::make_shared<BitCodeAbbrev>();
1126   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
1127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1130   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1131 
1132   // Abbrev for TYPE_CODE_ARRAY.
1133   Abbv = std::make_shared<BitCodeAbbrev>();
1134   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
1135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
1136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1137   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1138 
1139   // Emit an entry count so the reader can reserve space.
1140   TypeVals.push_back(TypeList.size());
1141   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
1142   TypeVals.clear();
1143 
1144   // Loop over all of the types, emitting each in turn.
1145   for (Type *T : TypeList) {
1146     int AbbrevToUse = 0;
1147     unsigned Code = 0;
1148 
1149     switch (T->getTypeID()) {
1150     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
1151     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
1152     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
1153     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
1154     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
1155     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
1156     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
1157     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
1158     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
1159     case Type::MetadataTyID:
1160       Code = bitc::TYPE_CODE_METADATA;
1161       break;
1162     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
1163     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
1164     case Type::IntegerTyID:
1165       // INTEGER: [width]
1166       Code = bitc::TYPE_CODE_INTEGER;
1167       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
1168       break;
1169     case Type::PointerTyID: {
1170       PointerType *PTy = cast<PointerType>(T);
1171       unsigned AddressSpace = PTy->getAddressSpace();
1172       // OPAQUE_POINTER: [address space]
1173       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1174       TypeVals.push_back(AddressSpace);
1175       if (AddressSpace == 0)
1176         AbbrevToUse = OpaquePtrAbbrev;
1177       break;
1178     }
1179     case Type::FunctionTyID: {
1180       FunctionType *FT = cast<FunctionType>(T);
1181       // FUNCTION: [isvararg, retty, paramty x N]
1182       Code = bitc::TYPE_CODE_FUNCTION;
1183       TypeVals.push_back(FT->isVarArg());
1184       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1185       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1186         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1187       AbbrevToUse = FunctionAbbrev;
1188       break;
1189     }
1190     case Type::StructTyID: {
1191       StructType *ST = cast<StructType>(T);
1192       // STRUCT: [ispacked, eltty x N]
1193       TypeVals.push_back(ST->isPacked());
1194       // Output all of the element types.
1195       for (Type *ET : ST->elements())
1196         TypeVals.push_back(VE.getTypeID(ET));
1197 
1198       if (ST->isLiteral()) {
1199         Code = bitc::TYPE_CODE_STRUCT_ANON;
1200         AbbrevToUse = StructAnonAbbrev;
1201       } else {
1202         if (ST->isOpaque()) {
1203           Code = bitc::TYPE_CODE_OPAQUE;
1204         } else {
1205           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1206           AbbrevToUse = StructNamedAbbrev;
1207         }
1208 
1209         // Emit the name if it is present.
1210         if (!ST->getName().empty())
1211           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1212                             StructNameAbbrev);
1213       }
1214       break;
1215     }
1216     case Type::ArrayTyID: {
1217       ArrayType *AT = cast<ArrayType>(T);
1218       // ARRAY: [numelts, eltty]
1219       Code = bitc::TYPE_CODE_ARRAY;
1220       TypeVals.push_back(AT->getNumElements());
1221       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1222       AbbrevToUse = ArrayAbbrev;
1223       break;
1224     }
1225     case Type::FixedVectorTyID:
1226     case Type::ScalableVectorTyID: {
1227       VectorType *VT = cast<VectorType>(T);
1228       // VECTOR [numelts, eltty] or
1229       //        [numelts, eltty, scalable]
1230       Code = bitc::TYPE_CODE_VECTOR;
1231       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1232       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1233       if (isa<ScalableVectorType>(VT))
1234         TypeVals.push_back(true);
1235       break;
1236     }
1237     case Type::TargetExtTyID: {
1238       TargetExtType *TET = cast<TargetExtType>(T);
1239       Code = bitc::TYPE_CODE_TARGET_TYPE;
1240       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1241                         StructNameAbbrev);
1242       TypeVals.push_back(TET->getNumTypeParameters());
1243       for (Type *InnerTy : TET->type_params())
1244         TypeVals.push_back(VE.getTypeID(InnerTy));
1245       llvm::append_range(TypeVals, TET->int_params());
1246       break;
1247     }
1248     case Type::TypedPointerTyID:
1249       llvm_unreachable("Typed pointers cannot be added to IR modules");
1250     }
1251 
1252     // Emit the finished record.
1253     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1254     TypeVals.clear();
1255   }
1256 
1257   Stream.ExitBlock();
1258 }
1259 
1260 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1261   switch (Linkage) {
1262   case GlobalValue::ExternalLinkage:
1263     return 0;
1264   case GlobalValue::WeakAnyLinkage:
1265     return 16;
1266   case GlobalValue::AppendingLinkage:
1267     return 2;
1268   case GlobalValue::InternalLinkage:
1269     return 3;
1270   case GlobalValue::LinkOnceAnyLinkage:
1271     return 18;
1272   case GlobalValue::ExternalWeakLinkage:
1273     return 7;
1274   case GlobalValue::CommonLinkage:
1275     return 8;
1276   case GlobalValue::PrivateLinkage:
1277     return 9;
1278   case GlobalValue::WeakODRLinkage:
1279     return 17;
1280   case GlobalValue::LinkOnceODRLinkage:
1281     return 19;
1282   case GlobalValue::AvailableExternallyLinkage:
1283     return 12;
1284   }
1285   llvm_unreachable("Invalid linkage");
1286 }
1287 
1288 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1289   return getEncodedLinkage(GV.getLinkage());
1290 }
1291 
1292 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1293   uint64_t RawFlags = 0;
1294   RawFlags |= Flags.ReadNone;
1295   RawFlags |= (Flags.ReadOnly << 1);
1296   RawFlags |= (Flags.NoRecurse << 2);
1297   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1298   RawFlags |= (Flags.NoInline << 4);
1299   RawFlags |= (Flags.AlwaysInline << 5);
1300   RawFlags |= (Flags.NoUnwind << 6);
1301   RawFlags |= (Flags.MayThrow << 7);
1302   RawFlags |= (Flags.HasUnknownCall << 8);
1303   RawFlags |= (Flags.MustBeUnreachable << 9);
1304   return RawFlags;
1305 }
1306 
1307 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1308 // in BitcodeReader.cpp.
1309 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
1310                                          bool ImportAsDecl = false) {
1311   uint64_t RawFlags = 0;
1312 
1313   RawFlags |= Flags.NotEligibleToImport; // bool
1314   RawFlags |= (Flags.Live << 1);
1315   RawFlags |= (Flags.DSOLocal << 2);
1316   RawFlags |= (Flags.CanAutoHide << 3);
1317 
1318   // Linkage don't need to be remapped at that time for the summary. Any future
1319   // change to the getEncodedLinkage() function will need to be taken into
1320   // account here as well.
1321   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1322 
1323   RawFlags |= (Flags.Visibility << 8); // 2 bits
1324 
1325   unsigned ImportType = Flags.ImportType | ImportAsDecl;
1326   RawFlags |= (ImportType << 10); // 1 bit
1327 
1328   return RawFlags;
1329 }
1330 
1331 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1332   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1333                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1334   return RawFlags;
1335 }
1336 
1337 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1338   uint64_t RawFlags = 0;
1339 
1340   RawFlags |= CI.Hotness;            // 3 bits
1341   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1342 
1343   return RawFlags;
1344 }
1345 
1346 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1347   uint64_t RawFlags = 0;
1348 
1349   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1350   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1351 
1352   return RawFlags;
1353 }
1354 
1355 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1356   switch (GV.getVisibility()) {
1357   case GlobalValue::DefaultVisibility:   return 0;
1358   case GlobalValue::HiddenVisibility:    return 1;
1359   case GlobalValue::ProtectedVisibility: return 2;
1360   }
1361   llvm_unreachable("Invalid visibility");
1362 }
1363 
1364 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1365   switch (GV.getDLLStorageClass()) {
1366   case GlobalValue::DefaultStorageClass:   return 0;
1367   case GlobalValue::DLLImportStorageClass: return 1;
1368   case GlobalValue::DLLExportStorageClass: return 2;
1369   }
1370   llvm_unreachable("Invalid DLL storage class");
1371 }
1372 
1373 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1374   switch (GV.getThreadLocalMode()) {
1375     case GlobalVariable::NotThreadLocal:         return 0;
1376     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1377     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1378     case GlobalVariable::InitialExecTLSModel:    return 3;
1379     case GlobalVariable::LocalExecTLSModel:      return 4;
1380   }
1381   llvm_unreachable("Invalid TLS model");
1382 }
1383 
1384 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1385   switch (C.getSelectionKind()) {
1386   case Comdat::Any:
1387     return bitc::COMDAT_SELECTION_KIND_ANY;
1388   case Comdat::ExactMatch:
1389     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1390   case Comdat::Largest:
1391     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1392   case Comdat::NoDeduplicate:
1393     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1394   case Comdat::SameSize:
1395     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1396   }
1397   llvm_unreachable("Invalid selection kind");
1398 }
1399 
1400 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1401   switch (GV.getUnnamedAddr()) {
1402   case GlobalValue::UnnamedAddr::None:   return 0;
1403   case GlobalValue::UnnamedAddr::Local:  return 2;
1404   case GlobalValue::UnnamedAddr::Global: return 1;
1405   }
1406   llvm_unreachable("Invalid unnamed_addr");
1407 }
1408 
1409 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1410   if (GenerateHash)
1411     Hasher.update(Str);
1412   return StrtabBuilder.add(Str);
1413 }
1414 
1415 void ModuleBitcodeWriter::writeComdats() {
1416   SmallVector<unsigned, 64> Vals;
1417   for (const Comdat *C : VE.getComdats()) {
1418     // COMDAT: [strtab offset, strtab size, selection_kind]
1419     Vals.push_back(addToStrtab(C->getName()));
1420     Vals.push_back(C->getName().size());
1421     Vals.push_back(getEncodedComdatSelectionKind(*C));
1422     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1423     Vals.clear();
1424   }
1425 }
1426 
1427 /// Write a record that will eventually hold the word offset of the
1428 /// module-level VST. For now the offset is 0, which will be backpatched
1429 /// after the real VST is written. Saves the bit offset to backpatch.
1430 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1431   // Write a placeholder value in for the offset of the real VST,
1432   // which is written after the function blocks so that it can include
1433   // the offset of each function. The placeholder offset will be
1434   // updated when the real VST is written.
1435   auto Abbv = std::make_shared<BitCodeAbbrev>();
1436   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1437   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1438   // hold the real VST offset. Must use fixed instead of VBR as we don't
1439   // know how many VBR chunks to reserve ahead of time.
1440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1441   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1442 
1443   // Emit the placeholder
1444   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1445   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1446 
1447   // Compute and save the bit offset to the placeholder, which will be
1448   // patched when the real VST is written. We can simply subtract the 32-bit
1449   // fixed size from the current bit number to get the location to backpatch.
1450   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1451 }
1452 
1453 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1454 
1455 /// Determine the encoding to use for the given string name and length.
1456 static StringEncoding getStringEncoding(StringRef Str) {
1457   bool isChar6 = true;
1458   for (char C : Str) {
1459     if (isChar6)
1460       isChar6 = BitCodeAbbrevOp::isChar6(C);
1461     if ((unsigned char)C & 128)
1462       // don't bother scanning the rest.
1463       return SE_Fixed8;
1464   }
1465   if (isChar6)
1466     return SE_Char6;
1467   return SE_Fixed7;
1468 }
1469 
1470 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1471               "Sanitizer Metadata is too large for naive serialization.");
1472 static unsigned
1473 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1474   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1475          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1476 }
1477 
1478 /// Emit top-level description of module, including target triple, inline asm,
1479 /// descriptors for global variables, and function prototype info.
1480 /// Returns the bit offset to backpatch with the location of the real VST.
1481 void ModuleBitcodeWriter::writeModuleInfo() {
1482   // Emit various pieces of data attached to a module.
1483   if (!M.getTargetTriple().empty())
1484     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE,
1485                       M.getTargetTriple().str(), 0 /*TODO*/);
1486   const std::string &DL = M.getDataLayoutStr();
1487   if (!DL.empty())
1488     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1489   if (!M.getModuleInlineAsm().empty())
1490     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1491                       0 /*TODO*/);
1492 
1493   // Emit information about sections and GC, computing how many there are. Also
1494   // compute the maximum alignment value.
1495   std::map<std::string, unsigned> SectionMap;
1496   std::map<std::string, unsigned> GCMap;
1497   MaybeAlign MaxAlignment;
1498   unsigned MaxGlobalType = 0;
1499   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1500     if (A)
1501       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1502   };
1503   for (const GlobalVariable &GV : M.globals()) {
1504     UpdateMaxAlignment(GV.getAlign());
1505     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1506     if (GV.hasSection()) {
1507       // Give section names unique ID's.
1508       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1509       if (!Entry) {
1510         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1511                           0 /*TODO*/);
1512         Entry = SectionMap.size();
1513       }
1514     }
1515   }
1516   for (const Function &F : M) {
1517     UpdateMaxAlignment(F.getAlign());
1518     if (F.hasSection()) {
1519       // Give section names unique ID's.
1520       unsigned &Entry = SectionMap[std::string(F.getSection())];
1521       if (!Entry) {
1522         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1523                           0 /*TODO*/);
1524         Entry = SectionMap.size();
1525       }
1526     }
1527     if (F.hasGC()) {
1528       // Same for GC names.
1529       unsigned &Entry = GCMap[F.getGC()];
1530       if (!Entry) {
1531         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1532                           0 /*TODO*/);
1533         Entry = GCMap.size();
1534       }
1535     }
1536   }
1537 
1538   // Emit abbrev for globals, now that we know # sections and max alignment.
1539   unsigned SimpleGVarAbbrev = 0;
1540   if (!M.global_empty()) {
1541     // Add an abbrev for common globals with no visibility or thread localness.
1542     auto Abbv = std::make_shared<BitCodeAbbrev>();
1543     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1544     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1547                               Log2_32_Ceil(MaxGlobalType+1)));
1548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1549                                                            //| explicitType << 1
1550                                                            //| constant
1551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1552     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1553     if (!MaxAlignment)                                     // Alignment.
1554       Abbv->Add(BitCodeAbbrevOp(0));
1555     else {
1556       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1557       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1558                                Log2_32_Ceil(MaxEncAlignment+1)));
1559     }
1560     if (SectionMap.empty())                                    // Section.
1561       Abbv->Add(BitCodeAbbrevOp(0));
1562     else
1563       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1564                                Log2_32_Ceil(SectionMap.size()+1)));
1565     // Don't bother emitting vis + thread local.
1566     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1567   }
1568 
1569   SmallVector<unsigned, 64> Vals;
1570   // Emit the module's source file name.
1571   {
1572     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1573     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1574     if (Bits == SE_Char6)
1575       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1576     else if (Bits == SE_Fixed7)
1577       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1578 
1579     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1580     auto Abbv = std::make_shared<BitCodeAbbrev>();
1581     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1583     Abbv->Add(AbbrevOpToUse);
1584     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1585 
1586     for (const auto P : M.getSourceFileName())
1587       Vals.push_back((unsigned char)P);
1588 
1589     // Emit the finished record.
1590     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1591     Vals.clear();
1592   }
1593 
1594   // Emit the global variable information.
1595   for (const GlobalVariable &GV : M.globals()) {
1596     unsigned AbbrevToUse = 0;
1597 
1598     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1599     //             linkage, alignment, section, visibility, threadlocal,
1600     //             unnamed_addr, externally_initialized, dllstorageclass,
1601     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1602     Vals.push_back(addToStrtab(GV.getName()));
1603     Vals.push_back(GV.getName().size());
1604     Vals.push_back(VE.getTypeID(GV.getValueType()));
1605     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1606     Vals.push_back(GV.isDeclaration() ? 0 :
1607                    (VE.getValueID(GV.getInitializer()) + 1));
1608     Vals.push_back(getEncodedLinkage(GV));
1609     Vals.push_back(getEncodedAlign(GV.getAlign()));
1610     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1611                                    : 0);
1612     if (GV.isThreadLocal() ||
1613         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1614         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1615         GV.isExternallyInitialized() ||
1616         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1617         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1618         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1619       Vals.push_back(getEncodedVisibility(GV));
1620       Vals.push_back(getEncodedThreadLocalMode(GV));
1621       Vals.push_back(getEncodedUnnamedAddr(GV));
1622       Vals.push_back(GV.isExternallyInitialized());
1623       Vals.push_back(getEncodedDLLStorageClass(GV));
1624       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1625 
1626       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1627       Vals.push_back(VE.getAttributeListID(AL));
1628 
1629       Vals.push_back(GV.isDSOLocal());
1630       Vals.push_back(addToStrtab(GV.getPartition()));
1631       Vals.push_back(GV.getPartition().size());
1632 
1633       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1634                                                       GV.getSanitizerMetadata())
1635                                                 : 0));
1636       Vals.push_back(GV.getCodeModelRaw());
1637     } else {
1638       AbbrevToUse = SimpleGVarAbbrev;
1639     }
1640 
1641     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1642     Vals.clear();
1643   }
1644 
1645   // Emit the function proto information.
1646   for (const Function &F : M) {
1647     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1648     //             linkage, paramattrs, alignment, section, visibility, gc,
1649     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1650     //             prefixdata, personalityfn, DSO_Local, addrspace]
1651     Vals.push_back(addToStrtab(F.getName()));
1652     Vals.push_back(F.getName().size());
1653     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1654     Vals.push_back(F.getCallingConv());
1655     Vals.push_back(F.isDeclaration());
1656     Vals.push_back(getEncodedLinkage(F));
1657     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1658     Vals.push_back(getEncodedAlign(F.getAlign()));
1659     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1660                                   : 0);
1661     Vals.push_back(getEncodedVisibility(F));
1662     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1663     Vals.push_back(getEncodedUnnamedAddr(F));
1664     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1665                                        : 0);
1666     Vals.push_back(getEncodedDLLStorageClass(F));
1667     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1668     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1669                                      : 0);
1670     Vals.push_back(
1671         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1672 
1673     Vals.push_back(F.isDSOLocal());
1674     Vals.push_back(F.getAddressSpace());
1675     Vals.push_back(addToStrtab(F.getPartition()));
1676     Vals.push_back(F.getPartition().size());
1677 
1678     unsigned AbbrevToUse = 0;
1679     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1680     Vals.clear();
1681   }
1682 
1683   // Emit the alias information.
1684   for (const GlobalAlias &A : M.aliases()) {
1685     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1686     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1687     //         DSO_Local]
1688     Vals.push_back(addToStrtab(A.getName()));
1689     Vals.push_back(A.getName().size());
1690     Vals.push_back(VE.getTypeID(A.getValueType()));
1691     Vals.push_back(A.getType()->getAddressSpace());
1692     Vals.push_back(VE.getValueID(A.getAliasee()));
1693     Vals.push_back(getEncodedLinkage(A));
1694     Vals.push_back(getEncodedVisibility(A));
1695     Vals.push_back(getEncodedDLLStorageClass(A));
1696     Vals.push_back(getEncodedThreadLocalMode(A));
1697     Vals.push_back(getEncodedUnnamedAddr(A));
1698     Vals.push_back(A.isDSOLocal());
1699     Vals.push_back(addToStrtab(A.getPartition()));
1700     Vals.push_back(A.getPartition().size());
1701 
1702     unsigned AbbrevToUse = 0;
1703     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1704     Vals.clear();
1705   }
1706 
1707   // Emit the ifunc information.
1708   for (const GlobalIFunc &I : M.ifuncs()) {
1709     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1710     //         val#, linkage, visibility, DSO_Local]
1711     Vals.push_back(addToStrtab(I.getName()));
1712     Vals.push_back(I.getName().size());
1713     Vals.push_back(VE.getTypeID(I.getValueType()));
1714     Vals.push_back(I.getType()->getAddressSpace());
1715     Vals.push_back(VE.getValueID(I.getResolver()));
1716     Vals.push_back(getEncodedLinkage(I));
1717     Vals.push_back(getEncodedVisibility(I));
1718     Vals.push_back(I.isDSOLocal());
1719     Vals.push_back(addToStrtab(I.getPartition()));
1720     Vals.push_back(I.getPartition().size());
1721     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1722     Vals.clear();
1723   }
1724 
1725   writeValueSymbolTableForwardDecl();
1726 }
1727 
1728 static uint64_t getOptimizationFlags(const Value *V) {
1729   uint64_t Flags = 0;
1730 
1731   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1732     if (OBO->hasNoSignedWrap())
1733       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1734     if (OBO->hasNoUnsignedWrap())
1735       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1736   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1737     if (PEO->isExact())
1738       Flags |= 1 << bitc::PEO_EXACT;
1739   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1740     if (PDI->isDisjoint())
1741       Flags |= 1 << bitc::PDI_DISJOINT;
1742   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1743     if (FPMO->hasAllowReassoc())
1744       Flags |= bitc::AllowReassoc;
1745     if (FPMO->hasNoNaNs())
1746       Flags |= bitc::NoNaNs;
1747     if (FPMO->hasNoInfs())
1748       Flags |= bitc::NoInfs;
1749     if (FPMO->hasNoSignedZeros())
1750       Flags |= bitc::NoSignedZeros;
1751     if (FPMO->hasAllowReciprocal())
1752       Flags |= bitc::AllowReciprocal;
1753     if (FPMO->hasAllowContract())
1754       Flags |= bitc::AllowContract;
1755     if (FPMO->hasApproxFunc())
1756       Flags |= bitc::ApproxFunc;
1757   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1758     if (NNI->hasNonNeg())
1759       Flags |= 1 << bitc::PNNI_NON_NEG;
1760   } else if (const auto *TI = dyn_cast<TruncInst>(V)) {
1761     if (TI->hasNoSignedWrap())
1762       Flags |= 1 << bitc::TIO_NO_SIGNED_WRAP;
1763     if (TI->hasNoUnsignedWrap())
1764       Flags |= 1 << bitc::TIO_NO_UNSIGNED_WRAP;
1765   } else if (const auto *GEP = dyn_cast<GEPOperator>(V)) {
1766     if (GEP->isInBounds())
1767       Flags |= 1 << bitc::GEP_INBOUNDS;
1768     if (GEP->hasNoUnsignedSignedWrap())
1769       Flags |= 1 << bitc::GEP_NUSW;
1770     if (GEP->hasNoUnsignedWrap())
1771       Flags |= 1 << bitc::GEP_NUW;
1772   } else if (const auto *ICmp = dyn_cast<ICmpInst>(V)) {
1773     if (ICmp->hasSameSign())
1774       Flags |= 1 << bitc::ICMP_SAME_SIGN;
1775   }
1776 
1777   return Flags;
1778 }
1779 
1780 void ModuleBitcodeWriter::writeValueAsMetadata(
1781     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1782   // Mimic an MDNode with a value as one operand.
1783   Value *V = MD->getValue();
1784   Record.push_back(VE.getTypeID(V->getType()));
1785   Record.push_back(VE.getValueID(V));
1786   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1787   Record.clear();
1788 }
1789 
1790 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1791                                        SmallVectorImpl<uint64_t> &Record,
1792                                        unsigned Abbrev) {
1793   for (const MDOperand &MDO : N->operands()) {
1794     Metadata *MD = MDO;
1795     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1796            "Unexpected function-local metadata");
1797     Record.push_back(VE.getMetadataOrNullID(MD));
1798   }
1799   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1800                                     : bitc::METADATA_NODE,
1801                     Record, Abbrev);
1802   Record.clear();
1803 }
1804 
1805 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1806   // Assume the column is usually under 128, and always output the inlined-at
1807   // location (it's never more expensive than building an array size 1).
1808   auto Abbv = std::make_shared<BitCodeAbbrev>();
1809   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1810   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isDistinct
1811   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // line
1812   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // column
1813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // scope
1814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // inlinedAt
1815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // isImplicitCode
1816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // atomGroup
1817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // atomRank
1818   return Stream.EmitAbbrev(std::move(Abbv));
1819 }
1820 
1821 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1822                                           SmallVectorImpl<uint64_t> &Record,
1823                                           unsigned &Abbrev) {
1824   if (!Abbrev)
1825     Abbrev = createDILocationAbbrev();
1826 
1827   Record.push_back(N->isDistinct());
1828   Record.push_back(N->getLine());
1829   Record.push_back(N->getColumn());
1830   Record.push_back(VE.getMetadataID(N->getScope()));
1831   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1832   Record.push_back(N->isImplicitCode());
1833   Record.push_back(N->getAtomGroup());
1834   Record.push_back(N->getAtomRank());
1835   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1836   Record.clear();
1837 }
1838 
1839 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1840   // Assume the column is usually under 128, and always output the inlined-at
1841   // location (it's never more expensive than building an array size 1).
1842   auto Abbv = std::make_shared<BitCodeAbbrev>();
1843   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1847   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1848   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1850   return Stream.EmitAbbrev(std::move(Abbv));
1851 }
1852 
1853 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1854                                              SmallVectorImpl<uint64_t> &Record,
1855                                              unsigned &Abbrev) {
1856   if (!Abbrev)
1857     Abbrev = createGenericDINodeAbbrev();
1858 
1859   Record.push_back(N->isDistinct());
1860   Record.push_back(N->getTag());
1861   Record.push_back(0); // Per-tag version field; unused for now.
1862 
1863   for (auto &I : N->operands())
1864     Record.push_back(VE.getMetadataOrNullID(I));
1865 
1866   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1867   Record.clear();
1868 }
1869 
1870 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1871                                           SmallVectorImpl<uint64_t> &Record,
1872                                           unsigned Abbrev) {
1873   const uint64_t Version = 2 << 1;
1874   Record.push_back((uint64_t)N->isDistinct() | Version);
1875   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1876   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1877   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1878   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1879 
1880   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1881   Record.clear();
1882 }
1883 
1884 void ModuleBitcodeWriter::writeDIGenericSubrange(
1885     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1886     unsigned Abbrev) {
1887   Record.push_back((uint64_t)N->isDistinct());
1888   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1889   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1890   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1891   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1892 
1893   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1894   Record.clear();
1895 }
1896 
1897 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1898                                             SmallVectorImpl<uint64_t> &Record,
1899                                             unsigned Abbrev) {
1900   const uint64_t IsBigInt = 1 << 2;
1901   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1902   Record.push_back(N->getValue().getBitWidth());
1903   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1904   emitWideAPInt(Record, N->getValue());
1905 
1906   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1907   Record.clear();
1908 }
1909 
1910 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1911                                            SmallVectorImpl<uint64_t> &Record,
1912                                            unsigned Abbrev) {
1913   const unsigned SizeIsMetadata = 0x2;
1914   Record.push_back(SizeIsMetadata | (unsigned)N->isDistinct());
1915   Record.push_back(N->getTag());
1916   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1917   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
1918   Record.push_back(N->getAlignInBits());
1919   Record.push_back(N->getEncoding());
1920   Record.push_back(N->getFlags());
1921   Record.push_back(N->getNumExtraInhabitants());
1922 
1923   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1924   Record.clear();
1925 }
1926 
1927 void ModuleBitcodeWriter::writeDIFixedPointType(
1928     const DIFixedPointType *N, SmallVectorImpl<uint64_t> &Record,
1929     unsigned Abbrev) {
1930   const unsigned SizeIsMetadata = 0x2;
1931   Record.push_back(SizeIsMetadata | (unsigned)N->isDistinct());
1932   Record.push_back(N->getTag());
1933   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
1935   Record.push_back(N->getAlignInBits());
1936   Record.push_back(N->getEncoding());
1937   Record.push_back(N->getFlags());
1938   Record.push_back(N->getKind());
1939   Record.push_back(N->getFactorRaw());
1940 
1941   auto WriteWideInt = [&](const APInt &Value) {
1942     // Write an encoded word that holds the number of active words and
1943     // the number of bits.
1944     uint64_t NumWords = Value.getActiveWords();
1945     uint64_t Encoded = (NumWords << 32) | Value.getBitWidth();
1946     Record.push_back(Encoded);
1947     emitWideAPInt(Record, Value);
1948   };
1949 
1950   WriteWideInt(N->getNumeratorRaw());
1951   WriteWideInt(N->getDenominatorRaw());
1952 
1953   Stream.EmitRecord(bitc::METADATA_FIXED_POINT_TYPE, Record, Abbrev);
1954   Record.clear();
1955 }
1956 
1957 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1958                                             SmallVectorImpl<uint64_t> &Record,
1959                                             unsigned Abbrev) {
1960   const unsigned SizeIsMetadata = 0x2;
1961   Record.push_back(SizeIsMetadata | (unsigned)N->isDistinct());
1962   Record.push_back(N->getTag());
1963   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1964   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1965   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1966   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1967   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
1968   Record.push_back(N->getAlignInBits());
1969   Record.push_back(N->getEncoding());
1970 
1971   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1972   Record.clear();
1973 }
1974 
1975 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1976                                              SmallVectorImpl<uint64_t> &Record,
1977                                              unsigned Abbrev) {
1978   const unsigned SizeIsMetadata = 0x2;
1979   Record.push_back(SizeIsMetadata | (unsigned)N->isDistinct());
1980   Record.push_back(N->getTag());
1981   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1982   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1983   Record.push_back(N->getLine());
1984   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1985   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1986   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
1987   Record.push_back(N->getAlignInBits());
1988   Record.push_back(VE.getMetadataOrNullID(N->getRawOffsetInBits()));
1989   Record.push_back(N->getFlags());
1990   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1991 
1992   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1993   // that there is no DWARF address space associated with DIDerivedType.
1994   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1995     Record.push_back(*DWARFAddressSpace + 1);
1996   else
1997     Record.push_back(0);
1998 
1999   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2000 
2001   if (auto PtrAuthData = N->getPtrAuthData())
2002     Record.push_back(PtrAuthData->RawData);
2003   else
2004     Record.push_back(0);
2005 
2006   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
2007   Record.clear();
2008 }
2009 
2010 void ModuleBitcodeWriter::writeDISubrangeType(const DISubrangeType *N,
2011                                               SmallVectorImpl<uint64_t> &Record,
2012                                               unsigned Abbrev) {
2013   const unsigned SizeIsMetadata = 0x2;
2014   Record.push_back(SizeIsMetadata | (unsigned)N->isDistinct());
2015   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2017   Record.push_back(N->getLine());
2018   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
2020   Record.push_back(N->getAlignInBits());
2021   Record.push_back(N->getFlags());
2022   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
2023   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
2024   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
2025   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
2026   Record.push_back(VE.getMetadataOrNullID(N->getRawBias()));
2027 
2028   Stream.EmitRecord(bitc::METADATA_SUBRANGE_TYPE, Record, Abbrev);
2029   Record.clear();
2030 }
2031 
2032 void ModuleBitcodeWriter::writeDICompositeType(
2033     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
2034     unsigned Abbrev) {
2035   const unsigned IsNotUsedInOldTypeRef = 0x2;
2036   const unsigned SizeIsMetadata = 0x4;
2037   Record.push_back(SizeIsMetadata | IsNotUsedInOldTypeRef |
2038                    (unsigned)N->isDistinct());
2039   Record.push_back(N->getTag());
2040   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2041   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2042   Record.push_back(N->getLine());
2043   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2044   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
2045   Record.push_back(VE.getMetadataOrNullID(N->getRawSizeInBits()));
2046   Record.push_back(N->getAlignInBits());
2047   Record.push_back(VE.getMetadataOrNullID(N->getRawOffsetInBits()));
2048   Record.push_back(N->getFlags());
2049   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2050   Record.push_back(N->getRuntimeLang());
2051   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
2052   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2053   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
2054   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
2055   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
2056   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
2057   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
2058   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2060   Record.push_back(N->getNumExtraInhabitants());
2061   Record.push_back(VE.getMetadataOrNullID(N->getRawSpecification()));
2062   Record.push_back(
2063       N->getEnumKind().value_or(dwarf::DW_APPLE_ENUM_KIND_invalid));
2064   Record.push_back(VE.getMetadataOrNullID(N->getRawBitStride()));
2065 
2066   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
2067   Record.clear();
2068 }
2069 
2070 void ModuleBitcodeWriter::writeDISubroutineType(
2071     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
2072     unsigned Abbrev) {
2073   const unsigned HasNoOldTypeRefs = 0x2;
2074   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
2075   Record.push_back(N->getFlags());
2076   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
2077   Record.push_back(N->getCC());
2078 
2079   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
2080   Record.clear();
2081 }
2082 
2083 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
2084                                       SmallVectorImpl<uint64_t> &Record,
2085                                       unsigned Abbrev) {
2086   Record.push_back(N->isDistinct());
2087   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
2088   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
2089   if (N->getRawChecksum()) {
2090     Record.push_back(N->getRawChecksum()->Kind);
2091     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
2092   } else {
2093     // Maintain backwards compatibility with the old internal representation of
2094     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
2095     Record.push_back(0);
2096     Record.push_back(VE.getMetadataOrNullID(nullptr));
2097   }
2098   auto Source = N->getRawSource();
2099   if (Source)
2100     Record.push_back(VE.getMetadataOrNullID(Source));
2101 
2102   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
2103   Record.clear();
2104 }
2105 
2106 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
2107                                              SmallVectorImpl<uint64_t> &Record,
2108                                              unsigned Abbrev) {
2109   assert(N->isDistinct() && "Expected distinct compile units");
2110   Record.push_back(/* IsDistinct */ true);
2111   Record.push_back(N->getSourceLanguage());
2112   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2113   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
2114   Record.push_back(N->isOptimized());
2115   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
2116   Record.push_back(N->getRuntimeVersion());
2117   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
2118   Record.push_back(N->getEmissionKind());
2119   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
2120   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
2121   Record.push_back(/* subprograms */ 0);
2122   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
2123   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
2124   Record.push_back(N->getDWOId());
2125   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
2126   Record.push_back(N->getSplitDebugInlining());
2127   Record.push_back(N->getDebugInfoForProfiling());
2128   Record.push_back((unsigned)N->getNameTableKind());
2129   Record.push_back(N->getRangesBaseAddress());
2130   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
2131   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
2132 
2133   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
2134   Record.clear();
2135 }
2136 
2137 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
2138                                             SmallVectorImpl<uint64_t> &Record,
2139                                             unsigned Abbrev) {
2140   const uint64_t HasUnitFlag = 1 << 1;
2141   const uint64_t HasSPFlagsFlag = 1 << 2;
2142   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
2143   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2144   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2145   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2146   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2147   Record.push_back(N->getLine());
2148   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2149   Record.push_back(N->getScopeLine());
2150   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
2151   Record.push_back(N->getSPFlags());
2152   Record.push_back(N->getVirtualIndex());
2153   Record.push_back(N->getFlags());
2154   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
2155   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2156   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
2157   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
2158   Record.push_back(N->getThisAdjustment());
2159   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
2160   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2161   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
2162   Record.push_back(N->getKeyInstructionsEnabled());
2163 
2164   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
2165   Record.clear();
2166 }
2167 
2168 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
2169                                               SmallVectorImpl<uint64_t> &Record,
2170                                               unsigned Abbrev) {
2171   Record.push_back(N->isDistinct());
2172   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2173   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2174   Record.push_back(N->getLine());
2175   Record.push_back(N->getColumn());
2176 
2177   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
2178   Record.clear();
2179 }
2180 
2181 void ModuleBitcodeWriter::writeDILexicalBlockFile(
2182     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
2183     unsigned Abbrev) {
2184   Record.push_back(N->isDistinct());
2185   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2186   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2187   Record.push_back(N->getDiscriminator());
2188 
2189   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
2190   Record.clear();
2191 }
2192 
2193 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
2194                                              SmallVectorImpl<uint64_t> &Record,
2195                                              unsigned Abbrev) {
2196   Record.push_back(N->isDistinct());
2197   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2198   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
2199   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2200   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2201   Record.push_back(N->getLineNo());
2202 
2203   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
2204   Record.clear();
2205 }
2206 
2207 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
2208                                            SmallVectorImpl<uint64_t> &Record,
2209                                            unsigned Abbrev) {
2210   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
2211   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2212   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2213 
2214   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
2215   Record.clear();
2216 }
2217 
2218 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
2219                                        SmallVectorImpl<uint64_t> &Record,
2220                                        unsigned Abbrev) {
2221   Record.push_back(N->isDistinct());
2222   Record.push_back(N->getMacinfoType());
2223   Record.push_back(N->getLine());
2224   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2225   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
2226 
2227   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
2228   Record.clear();
2229 }
2230 
2231 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
2232                                            SmallVectorImpl<uint64_t> &Record,
2233                                            unsigned Abbrev) {
2234   Record.push_back(N->isDistinct());
2235   Record.push_back(N->getMacinfoType());
2236   Record.push_back(N->getLine());
2237   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2238   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2239 
2240   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
2241   Record.clear();
2242 }
2243 
2244 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2245                                          SmallVectorImpl<uint64_t> &Record) {
2246   Record.reserve(N->getArgs().size());
2247   for (ValueAsMetadata *MD : N->getArgs())
2248     Record.push_back(VE.getMetadataID(MD));
2249 
2250   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2251   Record.clear();
2252 }
2253 
2254 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2255                                         SmallVectorImpl<uint64_t> &Record,
2256                                         unsigned Abbrev) {
2257   Record.push_back(N->isDistinct());
2258   for (auto &I : N->operands())
2259     Record.push_back(VE.getMetadataOrNullID(I));
2260   Record.push_back(N->getLineNo());
2261   Record.push_back(N->getIsDecl());
2262 
2263   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2264   Record.clear();
2265 }
2266 
2267 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2268                                           SmallVectorImpl<uint64_t> &Record,
2269                                           unsigned Abbrev) {
2270   // There are no arguments for this metadata type.
2271   Record.push_back(N->isDistinct());
2272   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2273   Record.clear();
2274 }
2275 
2276 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2277     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2278     unsigned Abbrev) {
2279   Record.push_back(N->isDistinct());
2280   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2281   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2282   Record.push_back(N->isDefault());
2283 
2284   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2285   Record.clear();
2286 }
2287 
2288 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2289     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2290     unsigned Abbrev) {
2291   Record.push_back(N->isDistinct());
2292   Record.push_back(N->getTag());
2293   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2294   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2295   Record.push_back(N->isDefault());
2296   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2297 
2298   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2299   Record.clear();
2300 }
2301 
2302 void ModuleBitcodeWriter::writeDIGlobalVariable(
2303     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2304     unsigned Abbrev) {
2305   const uint64_t Version = 2 << 1;
2306   Record.push_back((uint64_t)N->isDistinct() | Version);
2307   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2308   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2309   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2310   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2311   Record.push_back(N->getLine());
2312   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2313   Record.push_back(N->isLocalToUnit());
2314   Record.push_back(N->isDefinition());
2315   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2316   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2317   Record.push_back(N->getAlignInBits());
2318   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2319 
2320   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2321   Record.clear();
2322 }
2323 
2324 void ModuleBitcodeWriter::writeDILocalVariable(
2325     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2326     unsigned Abbrev) {
2327   // In order to support all possible bitcode formats in BitcodeReader we need
2328   // to distinguish the following cases:
2329   // 1) Record has no artificial tag (Record[1]),
2330   //   has no obsolete inlinedAt field (Record[9]).
2331   //   In this case Record size will be 8, HasAlignment flag is false.
2332   // 2) Record has artificial tag (Record[1]),
2333   //   has no obsolete inlignedAt field (Record[9]).
2334   //   In this case Record size will be 9, HasAlignment flag is false.
2335   // 3) Record has both artificial tag (Record[1]) and
2336   //   obsolete inlignedAt field (Record[9]).
2337   //   In this case Record size will be 10, HasAlignment flag is false.
2338   // 4) Record has neither artificial tag, nor inlignedAt field, but
2339   //   HasAlignment flag is true and Record[8] contains alignment value.
2340   const uint64_t HasAlignmentFlag = 1 << 1;
2341   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2342   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2343   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2344   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2345   Record.push_back(N->getLine());
2346   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2347   Record.push_back(N->getArg());
2348   Record.push_back(N->getFlags());
2349   Record.push_back(N->getAlignInBits());
2350   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2351 
2352   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2353   Record.clear();
2354 }
2355 
2356 void ModuleBitcodeWriter::writeDILabel(
2357     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2358     unsigned Abbrev) {
2359   uint64_t IsArtificialFlag = uint64_t(N->isArtificial()) << 1;
2360   Record.push_back((uint64_t)N->isDistinct() | IsArtificialFlag);
2361   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2362   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2363   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2364   Record.push_back(N->getLine());
2365   Record.push_back(N->getColumn());
2366   Record.push_back(N->getCoroSuspendIdx().has_value()
2367                        ? (uint64_t)N->getCoroSuspendIdx().value()
2368                        : std::numeric_limits<uint64_t>::max());
2369 
2370   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2371   Record.clear();
2372 }
2373 
2374 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2375                                             SmallVectorImpl<uint64_t> &Record,
2376                                             unsigned Abbrev) {
2377   Record.reserve(N->getElements().size() + 1);
2378   const uint64_t Version = 3 << 1;
2379   Record.push_back((uint64_t)N->isDistinct() | Version);
2380   Record.append(N->elements_begin(), N->elements_end());
2381 
2382   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2383   Record.clear();
2384 }
2385 
2386 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2387     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2388     unsigned Abbrev) {
2389   Record.push_back(N->isDistinct());
2390   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2391   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2392 
2393   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2394   Record.clear();
2395 }
2396 
2397 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2398                                               SmallVectorImpl<uint64_t> &Record,
2399                                               unsigned Abbrev) {
2400   Record.push_back(N->isDistinct());
2401   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2402   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2403   Record.push_back(N->getLine());
2404   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2405   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2406   Record.push_back(N->getAttributes());
2407   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2408 
2409   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2410   Record.clear();
2411 }
2412 
2413 void ModuleBitcodeWriter::writeDIImportedEntity(
2414     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2415     unsigned Abbrev) {
2416   Record.push_back(N->isDistinct());
2417   Record.push_back(N->getTag());
2418   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2419   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2420   Record.push_back(N->getLine());
2421   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2422   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2423   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2424 
2425   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2426   Record.clear();
2427 }
2428 
2429 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2430   auto Abbv = std::make_shared<BitCodeAbbrev>();
2431   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2434   return Stream.EmitAbbrev(std::move(Abbv));
2435 }
2436 
2437 void ModuleBitcodeWriter::writeNamedMetadata(
2438     SmallVectorImpl<uint64_t> &Record) {
2439   if (M.named_metadata_empty())
2440     return;
2441 
2442   unsigned Abbrev = createNamedMetadataAbbrev();
2443   for (const NamedMDNode &NMD : M.named_metadata()) {
2444     // Write name.
2445     StringRef Str = NMD.getName();
2446     Record.append(Str.bytes_begin(), Str.bytes_end());
2447     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2448     Record.clear();
2449 
2450     // Write named metadata operands.
2451     for (const MDNode *N : NMD.operands())
2452       Record.push_back(VE.getMetadataID(N));
2453     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2454     Record.clear();
2455   }
2456 }
2457 
2458 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2459   auto Abbv = std::make_shared<BitCodeAbbrev>();
2460   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2461   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2464   return Stream.EmitAbbrev(std::move(Abbv));
2465 }
2466 
2467 /// Write out a record for MDString.
2468 ///
2469 /// All the metadata strings in a metadata block are emitted in a single
2470 /// record.  The sizes and strings themselves are shoved into a blob.
2471 void ModuleBitcodeWriter::writeMetadataStrings(
2472     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2473   if (Strings.empty())
2474     return;
2475 
2476   // Start the record with the number of strings.
2477   Record.push_back(bitc::METADATA_STRINGS);
2478   Record.push_back(Strings.size());
2479 
2480   // Emit the sizes of the strings in the blob.
2481   SmallString<256> Blob;
2482   {
2483     BitstreamWriter W(Blob);
2484     for (const Metadata *MD : Strings)
2485       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2486     W.FlushToWord();
2487   }
2488 
2489   // Add the offset to the strings to the record.
2490   Record.push_back(Blob.size());
2491 
2492   // Add the strings to the blob.
2493   for (const Metadata *MD : Strings)
2494     Blob.append(cast<MDString>(MD)->getString());
2495 
2496   // Emit the final record.
2497   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2498   Record.clear();
2499 }
2500 
2501 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2502 enum MetadataAbbrev : unsigned {
2503 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2504 #include "llvm/IR/Metadata.def"
2505   LastPlusOne
2506 };
2507 
2508 void ModuleBitcodeWriter::writeMetadataRecords(
2509     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2510     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2511   if (MDs.empty())
2512     return;
2513 
2514   // Initialize MDNode abbreviations.
2515 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2516 #include "llvm/IR/Metadata.def"
2517 
2518   for (const Metadata *MD : MDs) {
2519     if (IndexPos)
2520       IndexPos->push_back(Stream.GetCurrentBitNo());
2521     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2522       assert(N->isResolved() && "Expected forward references to be resolved");
2523 
2524       switch (N->getMetadataID()) {
2525       default:
2526         llvm_unreachable("Invalid MDNode subclass");
2527 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2528   case Metadata::CLASS##Kind:                                                  \
2529     if (MDAbbrevs)                                                             \
2530       write##CLASS(cast<CLASS>(N), Record,                                     \
2531                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2532     else                                                                       \
2533       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2534     continue;
2535 #include "llvm/IR/Metadata.def"
2536       }
2537     }
2538     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2539       writeDIArgList(AL, Record);
2540       continue;
2541     }
2542     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2543   }
2544 }
2545 
2546 void ModuleBitcodeWriter::writeModuleMetadata() {
2547   if (!VE.hasMDs() && M.named_metadata_empty())
2548     return;
2549 
2550   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2551   SmallVector<uint64_t, 64> Record;
2552 
2553   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2554   // block and load any metadata.
2555   std::vector<unsigned> MDAbbrevs;
2556 
2557   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2558   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2559   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2560       createGenericDINodeAbbrev();
2561 
2562   auto Abbv = std::make_shared<BitCodeAbbrev>();
2563   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2564   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2566   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2567 
2568   Abbv = std::make_shared<BitCodeAbbrev>();
2569   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2570   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2571   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2572   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2573 
2574   // Emit MDStrings together upfront.
2575   writeMetadataStrings(VE.getMDStrings(), Record);
2576 
2577   // We only emit an index for the metadata record if we have more than a given
2578   // (naive) threshold of metadatas, otherwise it is not worth it.
2579   if (VE.getNonMDStrings().size() > IndexThreshold) {
2580     // Write a placeholder value in for the offset of the metadata index,
2581     // which is written after the records, so that it can include
2582     // the offset of each entry. The placeholder offset will be
2583     // updated after all records are emitted.
2584     uint64_t Vals[] = {0, 0};
2585     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2586   }
2587 
2588   // Compute and save the bit offset to the current position, which will be
2589   // patched when we emit the index later. We can simply subtract the 64-bit
2590   // fixed size from the current bit number to get the location to backpatch.
2591   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2592 
2593   // This index will contain the bitpos for each individual record.
2594   std::vector<uint64_t> IndexPos;
2595   IndexPos.reserve(VE.getNonMDStrings().size());
2596 
2597   // Write all the records
2598   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2599 
2600   if (VE.getNonMDStrings().size() > IndexThreshold) {
2601     // Now that we have emitted all the records we will emit the index. But
2602     // first
2603     // backpatch the forward reference so that the reader can skip the records
2604     // efficiently.
2605     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2606                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2607 
2608     // Delta encode the index.
2609     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2610     for (auto &Elt : IndexPos) {
2611       auto EltDelta = Elt - PreviousValue;
2612       PreviousValue = Elt;
2613       Elt = EltDelta;
2614     }
2615     // Emit the index record.
2616     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2617     IndexPos.clear();
2618   }
2619 
2620   // Write the named metadata now.
2621   writeNamedMetadata(Record);
2622 
2623   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2624     SmallVector<uint64_t, 4> Record;
2625     Record.push_back(VE.getValueID(&GO));
2626     pushGlobalMetadataAttachment(Record, GO);
2627     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2628   };
2629   for (const Function &F : M)
2630     if (F.isDeclaration() && F.hasMetadata())
2631       AddDeclAttachedMetadata(F);
2632   // FIXME: Only store metadata for declarations here, and move data for global
2633   // variable definitions to a separate block (PR28134).
2634   for (const GlobalVariable &GV : M.globals())
2635     if (GV.hasMetadata())
2636       AddDeclAttachedMetadata(GV);
2637 
2638   Stream.ExitBlock();
2639 }
2640 
2641 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2642   if (!VE.hasMDs())
2643     return;
2644 
2645   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2646   SmallVector<uint64_t, 64> Record;
2647   writeMetadataStrings(VE.getMDStrings(), Record);
2648   writeMetadataRecords(VE.getNonMDStrings(), Record);
2649   Stream.ExitBlock();
2650 }
2651 
2652 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2653     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2654   // [n x [id, mdnode]]
2655   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2656   GO.getAllMetadata(MDs);
2657   for (const auto &I : MDs) {
2658     Record.push_back(I.first);
2659     Record.push_back(VE.getMetadataID(I.second));
2660   }
2661 }
2662 
2663 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2664   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2665 
2666   SmallVector<uint64_t, 64> Record;
2667 
2668   if (F.hasMetadata()) {
2669     pushGlobalMetadataAttachment(Record, F);
2670     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2671     Record.clear();
2672   }
2673 
2674   // Write metadata attachments
2675   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2676   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2677   for (const BasicBlock &BB : F)
2678     for (const Instruction &I : BB) {
2679       MDs.clear();
2680       I.getAllMetadataOtherThanDebugLoc(MDs);
2681 
2682       // If no metadata, ignore instruction.
2683       if (MDs.empty()) continue;
2684 
2685       Record.push_back(VE.getInstructionID(&I));
2686 
2687       for (const auto &[ID, MD] : MDs) {
2688         Record.push_back(ID);
2689         Record.push_back(VE.getMetadataID(MD));
2690       }
2691       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2692       Record.clear();
2693     }
2694 
2695   Stream.ExitBlock();
2696 }
2697 
2698 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2699   SmallVector<uint64_t, 64> Record;
2700 
2701   // Write metadata kinds
2702   // METADATA_KIND - [n x [id, name]]
2703   SmallVector<StringRef, 8> Names;
2704   M.getMDKindNames(Names);
2705 
2706   if (Names.empty()) return;
2707 
2708   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2709 
2710   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2711     Record.push_back(MDKindID);
2712     StringRef KName = Names[MDKindID];
2713     Record.append(KName.begin(), KName.end());
2714 
2715     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2716     Record.clear();
2717   }
2718 
2719   Stream.ExitBlock();
2720 }
2721 
2722 void ModuleBitcodeWriter::writeOperandBundleTags() {
2723   // Write metadata kinds
2724   //
2725   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2726   //
2727   // OPERAND_BUNDLE_TAG - [strchr x N]
2728 
2729   SmallVector<StringRef, 8> Tags;
2730   M.getOperandBundleTags(Tags);
2731 
2732   if (Tags.empty())
2733     return;
2734 
2735   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2736 
2737   SmallVector<uint64_t, 64> Record;
2738 
2739   for (auto Tag : Tags) {
2740     Record.append(Tag.begin(), Tag.end());
2741 
2742     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2743     Record.clear();
2744   }
2745 
2746   Stream.ExitBlock();
2747 }
2748 
2749 void ModuleBitcodeWriter::writeSyncScopeNames() {
2750   SmallVector<StringRef, 8> SSNs;
2751   M.getContext().getSyncScopeNames(SSNs);
2752   if (SSNs.empty())
2753     return;
2754 
2755   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2756 
2757   SmallVector<uint64_t, 64> Record;
2758   for (auto SSN : SSNs) {
2759     Record.append(SSN.begin(), SSN.end());
2760     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2761     Record.clear();
2762   }
2763 
2764   Stream.ExitBlock();
2765 }
2766 
2767 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2768                                          bool isGlobal) {
2769   if (FirstVal == LastVal) return;
2770 
2771   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2772 
2773   unsigned AggregateAbbrev = 0;
2774   unsigned String8Abbrev = 0;
2775   unsigned CString7Abbrev = 0;
2776   unsigned CString6Abbrev = 0;
2777   // If this is a constant pool for the module, emit module-specific abbrevs.
2778   if (isGlobal) {
2779     // Abbrev for CST_CODE_AGGREGATE.
2780     auto Abbv = std::make_shared<BitCodeAbbrev>();
2781     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2782     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2784     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2785 
2786     // Abbrev for CST_CODE_STRING.
2787     Abbv = std::make_shared<BitCodeAbbrev>();
2788     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2790     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2791     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2792     // Abbrev for CST_CODE_CSTRING.
2793     Abbv = std::make_shared<BitCodeAbbrev>();
2794     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2797     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2798     // Abbrev for CST_CODE_CSTRING.
2799     Abbv = std::make_shared<BitCodeAbbrev>();
2800     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2801     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2802     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2803     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2804   }
2805 
2806   SmallVector<uint64_t, 64> Record;
2807 
2808   const ValueEnumerator::ValueList &Vals = VE.getValues();
2809   Type *LastTy = nullptr;
2810   for (unsigned i = FirstVal; i != LastVal; ++i) {
2811     const Value *V = Vals[i].first;
2812     // If we need to switch types, do so now.
2813     if (V->getType() != LastTy) {
2814       LastTy = V->getType();
2815       Record.push_back(VE.getTypeID(LastTy));
2816       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2817                         CONSTANTS_SETTYPE_ABBREV);
2818       Record.clear();
2819     }
2820 
2821     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2822       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2823       Record.push_back(
2824           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2825           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2826 
2827       // Add the asm string.
2828       StringRef AsmStr = IA->getAsmString();
2829       Record.push_back(AsmStr.size());
2830       Record.append(AsmStr.begin(), AsmStr.end());
2831 
2832       // Add the constraint string.
2833       StringRef ConstraintStr = IA->getConstraintString();
2834       Record.push_back(ConstraintStr.size());
2835       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2836       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2837       Record.clear();
2838       continue;
2839     }
2840     const Constant *C = cast<Constant>(V);
2841     unsigned Code = -1U;
2842     unsigned AbbrevToUse = 0;
2843     if (C->isNullValue()) {
2844       Code = bitc::CST_CODE_NULL;
2845     } else if (isa<PoisonValue>(C)) {
2846       Code = bitc::CST_CODE_POISON;
2847     } else if (isa<UndefValue>(C)) {
2848       Code = bitc::CST_CODE_UNDEF;
2849     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2850       if (IV->getBitWidth() <= 64) {
2851         uint64_t V = IV->getSExtValue();
2852         emitSignedInt64(Record, V);
2853         Code = bitc::CST_CODE_INTEGER;
2854         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2855       } else {                             // Wide integers, > 64 bits in size.
2856         emitWideAPInt(Record, IV->getValue());
2857         Code = bitc::CST_CODE_WIDE_INTEGER;
2858       }
2859     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2860       Code = bitc::CST_CODE_FLOAT;
2861       Type *Ty = CFP->getType()->getScalarType();
2862       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2863           Ty->isDoubleTy()) {
2864         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2865       } else if (Ty->isX86_FP80Ty()) {
2866         // api needed to prevent premature destruction
2867         // bits are not in the same order as a normal i80 APInt, compensate.
2868         APInt api = CFP->getValueAPF().bitcastToAPInt();
2869         const uint64_t *p = api.getRawData();
2870         Record.push_back((p[1] << 48) | (p[0] >> 16));
2871         Record.push_back(p[0] & 0xffffLL);
2872       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2873         APInt api = CFP->getValueAPF().bitcastToAPInt();
2874         const uint64_t *p = api.getRawData();
2875         Record.push_back(p[0]);
2876         Record.push_back(p[1]);
2877       } else {
2878         assert(0 && "Unknown FP type!");
2879       }
2880     } else if (isa<ConstantDataSequential>(C) &&
2881                cast<ConstantDataSequential>(C)->isString()) {
2882       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2883       // Emit constant strings specially.
2884       uint64_t NumElts = Str->getNumElements();
2885       // If this is a null-terminated string, use the denser CSTRING encoding.
2886       if (Str->isCString()) {
2887         Code = bitc::CST_CODE_CSTRING;
2888         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2889       } else {
2890         Code = bitc::CST_CODE_STRING;
2891         AbbrevToUse = String8Abbrev;
2892       }
2893       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2894       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2895       for (uint64_t i = 0; i != NumElts; ++i) {
2896         unsigned char V = Str->getElementAsInteger(i);
2897         Record.push_back(V);
2898         isCStr7 &= (V & 128) == 0;
2899         if (isCStrChar6)
2900           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2901       }
2902 
2903       if (isCStrChar6)
2904         AbbrevToUse = CString6Abbrev;
2905       else if (isCStr7)
2906         AbbrevToUse = CString7Abbrev;
2907     } else if (const ConstantDataSequential *CDS =
2908                   dyn_cast<ConstantDataSequential>(C)) {
2909       Code = bitc::CST_CODE_DATA;
2910       Type *EltTy = CDS->getElementType();
2911       if (isa<IntegerType>(EltTy)) {
2912         for (uint64_t i = 0, e = CDS->getNumElements(); i != e; ++i)
2913           Record.push_back(CDS->getElementAsInteger(i));
2914       } else {
2915         for (uint64_t i = 0, e = CDS->getNumElements(); i != e; ++i)
2916           Record.push_back(
2917               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2918       }
2919     } else if (isa<ConstantAggregate>(C)) {
2920       Code = bitc::CST_CODE_AGGREGATE;
2921       for (const Value *Op : C->operands())
2922         Record.push_back(VE.getValueID(Op));
2923       AbbrevToUse = AggregateAbbrev;
2924     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2925       switch (CE->getOpcode()) {
2926       default:
2927         if (Instruction::isCast(CE->getOpcode())) {
2928           Code = bitc::CST_CODE_CE_CAST;
2929           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2930           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2931           Record.push_back(VE.getValueID(C->getOperand(0)));
2932           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2933         } else {
2934           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2935           Code = bitc::CST_CODE_CE_BINOP;
2936           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2937           Record.push_back(VE.getValueID(C->getOperand(0)));
2938           Record.push_back(VE.getValueID(C->getOperand(1)));
2939           uint64_t Flags = getOptimizationFlags(CE);
2940           if (Flags != 0)
2941             Record.push_back(Flags);
2942         }
2943         break;
2944       case Instruction::FNeg: {
2945         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2946         Code = bitc::CST_CODE_CE_UNOP;
2947         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2948         Record.push_back(VE.getValueID(C->getOperand(0)));
2949         uint64_t Flags = getOptimizationFlags(CE);
2950         if (Flags != 0)
2951           Record.push_back(Flags);
2952         break;
2953       }
2954       case Instruction::GetElementPtr: {
2955         Code = bitc::CST_CODE_CE_GEP;
2956         const auto *GO = cast<GEPOperator>(C);
2957         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2958         Record.push_back(getOptimizationFlags(GO));
2959         if (std::optional<ConstantRange> Range = GO->getInRange()) {
2960           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE;
2961           emitConstantRange(Record, *Range, /*EmitBitWidth=*/true);
2962         }
2963         for (const Value *Op : CE->operands()) {
2964           Record.push_back(VE.getTypeID(Op->getType()));
2965           Record.push_back(VE.getValueID(Op));
2966         }
2967         break;
2968       }
2969       case Instruction::ExtractElement:
2970         Code = bitc::CST_CODE_CE_EXTRACTELT;
2971         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2972         Record.push_back(VE.getValueID(C->getOperand(0)));
2973         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2974         Record.push_back(VE.getValueID(C->getOperand(1)));
2975         break;
2976       case Instruction::InsertElement:
2977         Code = bitc::CST_CODE_CE_INSERTELT;
2978         Record.push_back(VE.getValueID(C->getOperand(0)));
2979         Record.push_back(VE.getValueID(C->getOperand(1)));
2980         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2981         Record.push_back(VE.getValueID(C->getOperand(2)));
2982         break;
2983       case Instruction::ShuffleVector:
2984         // If the return type and argument types are the same, this is a
2985         // standard shufflevector instruction.  If the types are different,
2986         // then the shuffle is widening or truncating the input vectors, and
2987         // the argument type must also be encoded.
2988         if (C->getType() == C->getOperand(0)->getType()) {
2989           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2990         } else {
2991           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2992           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2993         }
2994         Record.push_back(VE.getValueID(C->getOperand(0)));
2995         Record.push_back(VE.getValueID(C->getOperand(1)));
2996         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2997         break;
2998       }
2999     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
3000       Code = bitc::CST_CODE_BLOCKADDRESS;
3001       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
3002       Record.push_back(VE.getValueID(BA->getFunction()));
3003       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
3004     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
3005       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
3006       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
3007       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
3008     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
3009       Code = bitc::CST_CODE_NO_CFI_VALUE;
3010       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
3011       Record.push_back(VE.getValueID(NC->getGlobalValue()));
3012     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
3013       Code = bitc::CST_CODE_PTRAUTH;
3014       Record.push_back(VE.getValueID(CPA->getPointer()));
3015       Record.push_back(VE.getValueID(CPA->getKey()));
3016       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
3017       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
3018     } else {
3019 #ifndef NDEBUG
3020       C->dump();
3021 #endif
3022       llvm_unreachable("Unknown constant!");
3023     }
3024     Stream.EmitRecord(Code, Record, AbbrevToUse);
3025     Record.clear();
3026   }
3027 
3028   Stream.ExitBlock();
3029 }
3030 
3031 void ModuleBitcodeWriter::writeModuleConstants() {
3032   const ValueEnumerator::ValueList &Vals = VE.getValues();
3033 
3034   // Find the first constant to emit, which is the first non-globalvalue value.
3035   // We know globalvalues have been emitted by WriteModuleInfo.
3036   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
3037     if (!isa<GlobalValue>(Vals[i].first)) {
3038       writeConstants(i, Vals.size(), true);
3039       return;
3040     }
3041   }
3042 }
3043 
3044 /// pushValueAndType - The file has to encode both the value and type id for
3045 /// many values, because we need to know what type to create for forward
3046 /// references.  However, most operands are not forward references, so this type
3047 /// field is not needed.
3048 ///
3049 /// This function adds V's value ID to Vals.  If the value ID is higher than the
3050 /// instruction ID, then it is a forward reference, and it also includes the
3051 /// type ID.  The value ID that is written is encoded relative to the InstID.
3052 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
3053                                            SmallVectorImpl<unsigned> &Vals) {
3054   unsigned ValID = VE.getValueID(V);
3055   // Make encoding relative to the InstID.
3056   Vals.push_back(InstID - ValID);
3057   if (ValID >= InstID) {
3058     Vals.push_back(VE.getTypeID(V->getType()));
3059     return true;
3060   }
3061   return false;
3062 }
3063 
3064 bool ModuleBitcodeWriter::pushValueOrMetadata(const Value *V, unsigned InstID,
3065                                               SmallVectorImpl<unsigned> &Vals) {
3066   bool IsMetadata = V->getType()->isMetadataTy();
3067   if (IsMetadata) {
3068     Vals.push_back(bitc::OB_METADATA);
3069     Metadata *MD = cast<MetadataAsValue>(V)->getMetadata();
3070     unsigned ValID = VE.getMetadataID(MD);
3071     Vals.push_back(InstID - ValID);
3072     return false;
3073   }
3074   return pushValueAndType(V, InstID, Vals);
3075 }
3076 
3077 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
3078                                               unsigned InstID) {
3079   SmallVector<unsigned, 64> Record;
3080   LLVMContext &C = CS.getContext();
3081 
3082   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
3083     const auto &Bundle = CS.getOperandBundleAt(i);
3084     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
3085 
3086     for (auto &Input : Bundle.Inputs)
3087       pushValueOrMetadata(Input, InstID, Record);
3088 
3089     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
3090     Record.clear();
3091   }
3092 }
3093 
3094 /// pushValue - Like pushValueAndType, but where the type of the value is
3095 /// omitted (perhaps it was already encoded in an earlier operand).
3096 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
3097                                     SmallVectorImpl<unsigned> &Vals) {
3098   unsigned ValID = VE.getValueID(V);
3099   Vals.push_back(InstID - ValID);
3100 }
3101 
3102 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
3103                                           SmallVectorImpl<uint64_t> &Vals) {
3104   unsigned ValID = VE.getValueID(V);
3105   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
3106   emitSignedInt64(Vals, diff);
3107 }
3108 
3109 /// WriteInstruction - Emit an instruction to the specified stream.
3110 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
3111                                            unsigned InstID,
3112                                            SmallVectorImpl<unsigned> &Vals) {
3113   unsigned Code = 0;
3114   unsigned AbbrevToUse = 0;
3115   VE.setInstructionID(&I);
3116   switch (I.getOpcode()) {
3117   default:
3118     if (Instruction::isCast(I.getOpcode())) {
3119       Code = bitc::FUNC_CODE_INST_CAST;
3120       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3121         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
3122       Vals.push_back(VE.getTypeID(I.getType()));
3123       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
3124       uint64_t Flags = getOptimizationFlags(&I);
3125       if (Flags != 0) {
3126         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
3127           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
3128         Vals.push_back(Flags);
3129       }
3130     } else {
3131       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
3132       Code = bitc::FUNC_CODE_INST_BINOP;
3133       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3134         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
3135       pushValue(I.getOperand(1), InstID, Vals);
3136       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
3137       uint64_t Flags = getOptimizationFlags(&I);
3138       if (Flags != 0) {
3139         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
3140           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
3141         Vals.push_back(Flags);
3142       }
3143     }
3144     break;
3145   case Instruction::FNeg: {
3146     Code = bitc::FUNC_CODE_INST_UNOP;
3147     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3148       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
3149     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
3150     uint64_t Flags = getOptimizationFlags(&I);
3151     if (Flags != 0) {
3152       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
3153         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
3154       Vals.push_back(Flags);
3155     }
3156     break;
3157   }
3158   case Instruction::GetElementPtr: {
3159     Code = bitc::FUNC_CODE_INST_GEP;
3160     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
3161     auto &GEPInst = cast<GetElementPtrInst>(I);
3162     Vals.push_back(getOptimizationFlags(&I));
3163     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
3164     for (const Value *Op : I.operands())
3165       pushValueAndType(Op, InstID, Vals);
3166     break;
3167   }
3168   case Instruction::ExtractValue: {
3169     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
3170     pushValueAndType(I.getOperand(0), InstID, Vals);
3171     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
3172     Vals.append(EVI->idx_begin(), EVI->idx_end());
3173     break;
3174   }
3175   case Instruction::InsertValue: {
3176     Code = bitc::FUNC_CODE_INST_INSERTVAL;
3177     pushValueAndType(I.getOperand(0), InstID, Vals);
3178     pushValueAndType(I.getOperand(1), InstID, Vals);
3179     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
3180     Vals.append(IVI->idx_begin(), IVI->idx_end());
3181     break;
3182   }
3183   case Instruction::Select: {
3184     Code = bitc::FUNC_CODE_INST_VSELECT;
3185     pushValueAndType(I.getOperand(1), InstID, Vals);
3186     pushValue(I.getOperand(2), InstID, Vals);
3187     pushValueAndType(I.getOperand(0), InstID, Vals);
3188     uint64_t Flags = getOptimizationFlags(&I);
3189     if (Flags != 0)
3190       Vals.push_back(Flags);
3191     break;
3192   }
3193   case Instruction::ExtractElement:
3194     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
3195     pushValueAndType(I.getOperand(0), InstID, Vals);
3196     pushValueAndType(I.getOperand(1), InstID, Vals);
3197     break;
3198   case Instruction::InsertElement:
3199     Code = bitc::FUNC_CODE_INST_INSERTELT;
3200     pushValueAndType(I.getOperand(0), InstID, Vals);
3201     pushValue(I.getOperand(1), InstID, Vals);
3202     pushValueAndType(I.getOperand(2), InstID, Vals);
3203     break;
3204   case Instruction::ShuffleVector:
3205     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
3206     pushValueAndType(I.getOperand(0), InstID, Vals);
3207     pushValue(I.getOperand(1), InstID, Vals);
3208     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
3209               Vals);
3210     break;
3211   case Instruction::ICmp:
3212   case Instruction::FCmp: {
3213     // compare returning Int1Ty or vector of Int1Ty
3214     Code = bitc::FUNC_CODE_INST_CMP2;
3215     AbbrevToUse = FUNCTION_INST_CMP_ABBREV;
3216     if (pushValueAndType(I.getOperand(0), InstID, Vals))
3217       AbbrevToUse = 0;
3218     pushValue(I.getOperand(1), InstID, Vals);
3219     Vals.push_back(cast<CmpInst>(I).getPredicate());
3220     uint64_t Flags = getOptimizationFlags(&I);
3221     if (Flags != 0) {
3222       Vals.push_back(Flags);
3223       if (AbbrevToUse)
3224         AbbrevToUse = FUNCTION_INST_CMP_FLAGS_ABBREV;
3225     }
3226     break;
3227   }
3228 
3229   case Instruction::Ret:
3230     {
3231       Code = bitc::FUNC_CODE_INST_RET;
3232       unsigned NumOperands = I.getNumOperands();
3233       if (NumOperands == 0)
3234         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
3235       else if (NumOperands == 1) {
3236         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3237           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
3238       } else {
3239         for (const Value *Op : I.operands())
3240           pushValueAndType(Op, InstID, Vals);
3241       }
3242     }
3243     break;
3244   case Instruction::Br:
3245     {
3246       Code = bitc::FUNC_CODE_INST_BR;
3247       AbbrevToUse = FUNCTION_INST_BR_UNCOND_ABBREV;
3248       const BranchInst &II = cast<BranchInst>(I);
3249       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
3250       if (II.isConditional()) {
3251         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
3252         pushValue(II.getCondition(), InstID, Vals);
3253         AbbrevToUse = FUNCTION_INST_BR_COND_ABBREV;
3254       }
3255     }
3256     break;
3257   case Instruction::Switch:
3258     {
3259       Code = bitc::FUNC_CODE_INST_SWITCH;
3260       const SwitchInst &SI = cast<SwitchInst>(I);
3261       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
3262       pushValue(SI.getCondition(), InstID, Vals);
3263       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
3264       for (auto Case : SI.cases()) {
3265         Vals.push_back(VE.getValueID(Case.getCaseValue()));
3266         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3267       }
3268     }
3269     break;
3270   case Instruction::IndirectBr:
3271     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3272     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3273     // Encode the address operand as relative, but not the basic blocks.
3274     pushValue(I.getOperand(0), InstID, Vals);
3275     for (const Value *Op : drop_begin(I.operands()))
3276       Vals.push_back(VE.getValueID(Op));
3277     break;
3278 
3279   case Instruction::Invoke: {
3280     const InvokeInst *II = cast<InvokeInst>(&I);
3281     const Value *Callee = II->getCalledOperand();
3282     FunctionType *FTy = II->getFunctionType();
3283 
3284     if (II->hasOperandBundles())
3285       writeOperandBundles(*II, InstID);
3286 
3287     Code = bitc::FUNC_CODE_INST_INVOKE;
3288 
3289     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3290     Vals.push_back(II->getCallingConv() | 1 << 13);
3291     Vals.push_back(VE.getValueID(II->getNormalDest()));
3292     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3293     Vals.push_back(VE.getTypeID(FTy));
3294     pushValueAndType(Callee, InstID, Vals);
3295 
3296     // Emit value #'s for the fixed parameters.
3297     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3298       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3299 
3300     // Emit type/value pairs for varargs params.
3301     if (FTy->isVarArg()) {
3302       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3303         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3304     }
3305     break;
3306   }
3307   case Instruction::Resume:
3308     Code = bitc::FUNC_CODE_INST_RESUME;
3309     pushValueAndType(I.getOperand(0), InstID, Vals);
3310     break;
3311   case Instruction::CleanupRet: {
3312     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3313     const auto &CRI = cast<CleanupReturnInst>(I);
3314     pushValue(CRI.getCleanupPad(), InstID, Vals);
3315     if (CRI.hasUnwindDest())
3316       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3317     break;
3318   }
3319   case Instruction::CatchRet: {
3320     Code = bitc::FUNC_CODE_INST_CATCHRET;
3321     const auto &CRI = cast<CatchReturnInst>(I);
3322     pushValue(CRI.getCatchPad(), InstID, Vals);
3323     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3324     break;
3325   }
3326   case Instruction::CleanupPad:
3327   case Instruction::CatchPad: {
3328     const auto &FuncletPad = cast<FuncletPadInst>(I);
3329     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3330                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3331     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3332 
3333     unsigned NumArgOperands = FuncletPad.arg_size();
3334     Vals.push_back(NumArgOperands);
3335     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3336       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3337     break;
3338   }
3339   case Instruction::CatchSwitch: {
3340     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3341     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3342 
3343     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3344 
3345     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3346     Vals.push_back(NumHandlers);
3347     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3348       Vals.push_back(VE.getValueID(CatchPadBB));
3349 
3350     if (CatchSwitch.hasUnwindDest())
3351       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3352     break;
3353   }
3354   case Instruction::CallBr: {
3355     const CallBrInst *CBI = cast<CallBrInst>(&I);
3356     const Value *Callee = CBI->getCalledOperand();
3357     FunctionType *FTy = CBI->getFunctionType();
3358 
3359     if (CBI->hasOperandBundles())
3360       writeOperandBundles(*CBI, InstID);
3361 
3362     Code = bitc::FUNC_CODE_INST_CALLBR;
3363 
3364     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3365 
3366     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3367                    1 << bitc::CALL_EXPLICIT_TYPE);
3368 
3369     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3370     Vals.push_back(CBI->getNumIndirectDests());
3371     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3372       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3373 
3374     Vals.push_back(VE.getTypeID(FTy));
3375     pushValueAndType(Callee, InstID, Vals);
3376 
3377     // Emit value #'s for the fixed parameters.
3378     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3379       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3380 
3381     // Emit type/value pairs for varargs params.
3382     if (FTy->isVarArg()) {
3383       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3384         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3385     }
3386     break;
3387   }
3388   case Instruction::Unreachable:
3389     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3390     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3391     break;
3392 
3393   case Instruction::PHI: {
3394     const PHINode &PN = cast<PHINode>(I);
3395     Code = bitc::FUNC_CODE_INST_PHI;
3396     // With the newer instruction encoding, forward references could give
3397     // negative valued IDs.  This is most common for PHIs, so we use
3398     // signed VBRs.
3399     SmallVector<uint64_t, 128> Vals64;
3400     Vals64.push_back(VE.getTypeID(PN.getType()));
3401     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3402       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3403       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3404     }
3405 
3406     uint64_t Flags = getOptimizationFlags(&I);
3407     if (Flags != 0)
3408       Vals64.push_back(Flags);
3409 
3410     // Emit a Vals64 vector and exit.
3411     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3412     Vals64.clear();
3413     return;
3414   }
3415 
3416   case Instruction::LandingPad: {
3417     const LandingPadInst &LP = cast<LandingPadInst>(I);
3418     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3419     Vals.push_back(VE.getTypeID(LP.getType()));
3420     Vals.push_back(LP.isCleanup());
3421     Vals.push_back(LP.getNumClauses());
3422     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3423       if (LP.isCatch(I))
3424         Vals.push_back(LandingPadInst::Catch);
3425       else
3426         Vals.push_back(LandingPadInst::Filter);
3427       pushValueAndType(LP.getClause(I), InstID, Vals);
3428     }
3429     break;
3430   }
3431 
3432   case Instruction::Alloca: {
3433     Code = bitc::FUNC_CODE_INST_ALLOCA;
3434     const AllocaInst &AI = cast<AllocaInst>(I);
3435     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3436     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3437     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3438     using APV = AllocaPackedValues;
3439     unsigned Record = 0;
3440     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3441     Bitfield::set<APV::AlignLower>(
3442         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3443     Bitfield::set<APV::AlignUpper>(Record,
3444                                    EncodedAlign >> APV::AlignLower::Bits);
3445     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3446     Bitfield::set<APV::ExplicitType>(Record, true);
3447     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3448     Vals.push_back(Record);
3449 
3450     unsigned AS = AI.getAddressSpace();
3451     if (AS != M.getDataLayout().getAllocaAddrSpace())
3452       Vals.push_back(AS);
3453     break;
3454   }
3455 
3456   case Instruction::Load:
3457     if (cast<LoadInst>(I).isAtomic()) {
3458       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3459       pushValueAndType(I.getOperand(0), InstID, Vals);
3460     } else {
3461       Code = bitc::FUNC_CODE_INST_LOAD;
3462       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3463         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3464     }
3465     Vals.push_back(VE.getTypeID(I.getType()));
3466     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3467     Vals.push_back(cast<LoadInst>(I).isVolatile());
3468     if (cast<LoadInst>(I).isAtomic()) {
3469       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3470       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3471     }
3472     break;
3473   case Instruction::Store:
3474     if (cast<StoreInst>(I).isAtomic()) {
3475       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3476     } else {
3477       Code = bitc::FUNC_CODE_INST_STORE;
3478       AbbrevToUse = FUNCTION_INST_STORE_ABBREV;
3479     }
3480     if (pushValueAndType(I.getOperand(1), InstID, Vals)) // ptrty + ptr
3481       AbbrevToUse = 0;
3482     if (pushValueAndType(I.getOperand(0), InstID, Vals)) // valty + val
3483       AbbrevToUse = 0;
3484     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3485     Vals.push_back(cast<StoreInst>(I).isVolatile());
3486     if (cast<StoreInst>(I).isAtomic()) {
3487       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3488       Vals.push_back(
3489           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3490     }
3491     break;
3492   case Instruction::AtomicCmpXchg:
3493     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3494     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3495     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3496     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3497     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3498     Vals.push_back(
3499         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3500     Vals.push_back(
3501         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3502     Vals.push_back(
3503         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3504     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3505     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3506     break;
3507   case Instruction::AtomicRMW:
3508     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3509     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3510     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3511     Vals.push_back(
3512         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3513     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3514     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3515     Vals.push_back(
3516         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3517     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3518     break;
3519   case Instruction::Fence:
3520     Code = bitc::FUNC_CODE_INST_FENCE;
3521     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3522     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3523     break;
3524   case Instruction::Call: {
3525     const CallInst &CI = cast<CallInst>(I);
3526     FunctionType *FTy = CI.getFunctionType();
3527 
3528     if (CI.hasOperandBundles())
3529       writeOperandBundles(CI, InstID);
3530 
3531     Code = bitc::FUNC_CODE_INST_CALL;
3532 
3533     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3534 
3535     unsigned Flags = getOptimizationFlags(&I);
3536     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3537                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3538                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3539                    1 << bitc::CALL_EXPLICIT_TYPE |
3540                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3541                    unsigned(Flags != 0) << bitc::CALL_FMF);
3542     if (Flags != 0)
3543       Vals.push_back(Flags);
3544 
3545     Vals.push_back(VE.getTypeID(FTy));
3546     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3547 
3548     // Emit value #'s for the fixed parameters.
3549     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3550       pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3551 
3552     // Emit type/value pairs for varargs params.
3553     if (FTy->isVarArg()) {
3554       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3555         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3556     }
3557     break;
3558   }
3559   case Instruction::VAArg:
3560     Code = bitc::FUNC_CODE_INST_VAARG;
3561     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3562     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3563     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3564     break;
3565   case Instruction::Freeze:
3566     Code = bitc::FUNC_CODE_INST_FREEZE;
3567     pushValueAndType(I.getOperand(0), InstID, Vals);
3568     break;
3569   }
3570 
3571   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3572   Vals.clear();
3573 }
3574 
3575 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3576 /// to allow clients to efficiently find the function body.
3577 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3578   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3579   // Get the offset of the VST we are writing, and backpatch it into
3580   // the VST forward declaration record.
3581   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3582   // The BitcodeStartBit was the stream offset of the identification block.
3583   VSTOffset -= bitcodeStartBit();
3584   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3585   // Note that we add 1 here because the offset is relative to one word
3586   // before the start of the identification block, which was historically
3587   // always the start of the regular bitcode header.
3588   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3589 
3590   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3591 
3592   auto Abbv = std::make_shared<BitCodeAbbrev>();
3593   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3596   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3597 
3598   for (const Function &F : M) {
3599     uint64_t Record[2];
3600 
3601     if (F.isDeclaration())
3602       continue;
3603 
3604     Record[0] = VE.getValueID(&F);
3605 
3606     // Save the word offset of the function (from the start of the
3607     // actual bitcode written to the stream).
3608     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3609     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3610     // Note that we add 1 here because the offset is relative to one word
3611     // before the start of the identification block, which was historically
3612     // always the start of the regular bitcode header.
3613     Record[1] = BitcodeIndex / 32 + 1;
3614 
3615     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3616   }
3617 
3618   Stream.ExitBlock();
3619 }
3620 
3621 /// Emit names for arguments, instructions and basic blocks in a function.
3622 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3623     const ValueSymbolTable &VST) {
3624   if (VST.empty())
3625     return;
3626 
3627   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3628 
3629   // FIXME: Set up the abbrev, we know how many values there are!
3630   // FIXME: We know if the type names can use 7-bit ascii.
3631   SmallVector<uint64_t, 64> NameVals;
3632 
3633   for (const ValueName &Name : VST) {
3634     // Figure out the encoding to use for the name.
3635     StringEncoding Bits = getStringEncoding(Name.getKey());
3636 
3637     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3638     NameVals.push_back(VE.getValueID(Name.getValue()));
3639 
3640     // VST_CODE_ENTRY:   [valueid, namechar x N]
3641     // VST_CODE_BBENTRY: [bbid, namechar x N]
3642     unsigned Code;
3643     if (isa<BasicBlock>(Name.getValue())) {
3644       Code = bitc::VST_CODE_BBENTRY;
3645       if (Bits == SE_Char6)
3646         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3647     } else {
3648       Code = bitc::VST_CODE_ENTRY;
3649       if (Bits == SE_Char6)
3650         AbbrevToUse = VST_ENTRY_6_ABBREV;
3651       else if (Bits == SE_Fixed7)
3652         AbbrevToUse = VST_ENTRY_7_ABBREV;
3653     }
3654 
3655     for (const auto P : Name.getKey())
3656       NameVals.push_back((unsigned char)P);
3657 
3658     // Emit the finished record.
3659     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3660     NameVals.clear();
3661   }
3662 
3663   Stream.ExitBlock();
3664 }
3665 
3666 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3667   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3668   unsigned Code;
3669   if (isa<BasicBlock>(Order.V))
3670     Code = bitc::USELIST_CODE_BB;
3671   else
3672     Code = bitc::USELIST_CODE_DEFAULT;
3673 
3674   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3675   Record.push_back(VE.getValueID(Order.V));
3676   Stream.EmitRecord(Code, Record);
3677 }
3678 
3679 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3680   assert(VE.shouldPreserveUseListOrder() &&
3681          "Expected to be preserving use-list order");
3682 
3683   auto hasMore = [&]() {
3684     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3685   };
3686   if (!hasMore())
3687     // Nothing to do.
3688     return;
3689 
3690   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3691   while (hasMore()) {
3692     writeUseList(std::move(VE.UseListOrders.back()));
3693     VE.UseListOrders.pop_back();
3694   }
3695   Stream.ExitBlock();
3696 }
3697 
3698 /// Emit a function body to the module stream.
3699 void ModuleBitcodeWriter::writeFunction(
3700     const Function &F,
3701     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3702   // Save the bitcode index of the start of this function block for recording
3703   // in the VST.
3704   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3705 
3706   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 5);
3707   VE.incorporateFunction(F);
3708 
3709   SmallVector<unsigned, 64> Vals;
3710 
3711   // Emit the number of basic blocks, so the reader can create them ahead of
3712   // time.
3713   Vals.push_back(VE.getBasicBlocks().size());
3714   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3715   Vals.clear();
3716 
3717   // If there are function-local constants, emit them now.
3718   unsigned CstStart, CstEnd;
3719   VE.getFunctionConstantRange(CstStart, CstEnd);
3720   writeConstants(CstStart, CstEnd, false);
3721 
3722   // If there is function-local metadata, emit it now.
3723   writeFunctionMetadata(F);
3724 
3725   // Keep a running idea of what the instruction ID is.
3726   unsigned InstID = CstEnd;
3727 
3728   bool NeedsMetadataAttachment = F.hasMetadata();
3729 
3730   DILocation *LastDL = nullptr;
3731   SmallSetVector<Function *, 4> BlockAddressUsers;
3732 
3733   // Finally, emit all the instructions, in order.
3734   for (const BasicBlock &BB : F) {
3735     for (const Instruction &I : BB) {
3736       writeInstruction(I, InstID, Vals);
3737 
3738       if (!I.getType()->isVoidTy())
3739         ++InstID;
3740 
3741       // If the instruction has metadata, write a metadata attachment later.
3742       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3743 
3744       // If the instruction has a debug location, emit it.
3745       if (DILocation *DL = I.getDebugLoc()) {
3746         if (DL == LastDL) {
3747           // Just repeat the same debug loc as last time.
3748           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3749         } else {
3750           Vals.push_back(DL->getLine());
3751           Vals.push_back(DL->getColumn());
3752           Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3753           Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3754           Vals.push_back(DL->isImplicitCode());
3755           Vals.push_back(DL->getAtomGroup());
3756           Vals.push_back(DL->getAtomRank());
3757           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals,
3758                             FUNCTION_DEBUG_LOC_ABBREV);
3759           Vals.clear();
3760           LastDL = DL;
3761         }
3762       }
3763 
3764       // If the instruction has DbgRecords attached to it, emit them. Note that
3765       // they come after the instruction so that it's easy to attach them again
3766       // when reading the bitcode, even though conceptually the debug locations
3767       // start "before" the instruction.
3768       if (I.hasDbgRecords()) {
3769         /// Try to push the value only (unwrapped), otherwise push the
3770         /// metadata wrapped value. Returns true if the value was pushed
3771         /// without the ValueAsMetadata wrapper.
3772         auto PushValueOrMetadata = [&Vals, InstID,
3773                                     this](Metadata *RawLocation) {
3774           assert(RawLocation &&
3775                  "RawLocation unexpectedly null in DbgVariableRecord");
3776           if (ValueAsMetadata *VAM = dyn_cast<ValueAsMetadata>(RawLocation)) {
3777             SmallVector<unsigned, 2> ValAndType;
3778             // If the value is a fwd-ref the type is also pushed. We don't
3779             // want the type, so fwd-refs are kept wrapped (pushValueAndType
3780             // returns false if the value is pushed without type).
3781             if (!pushValueAndType(VAM->getValue(), InstID, ValAndType)) {
3782               Vals.push_back(ValAndType[0]);
3783               return true;
3784             }
3785           }
3786           // The metadata is a DIArgList, or ValueAsMetadata wrapping a
3787           // fwd-ref. Push the metadata ID.
3788           Vals.push_back(VE.getMetadataID(RawLocation));
3789           return false;
3790         };
3791 
3792         // Write out non-instruction debug information attached to this
3793         // instruction. Write it after the instruction so that it's easy to
3794         // re-attach to the instruction reading the records in.
3795         for (DbgRecord &DR : I.DebugMarker->getDbgRecordRange()) {
3796           if (DbgLabelRecord *DLR = dyn_cast<DbgLabelRecord>(&DR)) {
3797             Vals.push_back(VE.getMetadataID(&*DLR->getDebugLoc()));
3798             Vals.push_back(VE.getMetadataID(DLR->getLabel()));
3799             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_LABEL, Vals);
3800             Vals.clear();
3801             continue;
3802           }
3803 
3804           // First 3 fields are common to all kinds:
3805           //   DILocation, DILocalVariable, DIExpression
3806           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE)
3807           //   ..., LocationMetadata
3808           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE - abbrev'd)
3809           //   ..., Value
3810           // dbg_declare (FUNC_CODE_DEBUG_RECORD_DECLARE)
3811           //   ..., LocationMetadata
3812           // dbg_assign (FUNC_CODE_DEBUG_RECORD_ASSIGN)
3813           //   ..., LocationMetadata, DIAssignID, DIExpression, LocationMetadata
3814           DbgVariableRecord &DVR = cast<DbgVariableRecord>(DR);
3815           Vals.push_back(VE.getMetadataID(&*DVR.getDebugLoc()));
3816           Vals.push_back(VE.getMetadataID(DVR.getVariable()));
3817           Vals.push_back(VE.getMetadataID(DVR.getExpression()));
3818           if (DVR.isDbgValue()) {
3819             if (PushValueOrMetadata(DVR.getRawLocation()))
3820               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE, Vals,
3821                                 FUNCTION_DEBUG_RECORD_VALUE_ABBREV);
3822             else
3823               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE, Vals);
3824           } else if (DVR.isDbgDeclare()) {
3825             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3826             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_DECLARE, Vals);
3827           } else {
3828             assert(DVR.isDbgAssign() && "Unexpected DbgRecord kind");
3829             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3830             Vals.push_back(VE.getMetadataID(DVR.getAssignID()));
3831             Vals.push_back(VE.getMetadataID(DVR.getAddressExpression()));
3832             Vals.push_back(VE.getMetadataID(DVR.getRawAddress()));
3833             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_ASSIGN, Vals);
3834           }
3835           Vals.clear();
3836         }
3837       }
3838     }
3839 
3840     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3841       SmallVector<Value *> Worklist{BA};
3842       SmallPtrSet<Value *, 8> Visited{BA};
3843       while (!Worklist.empty()) {
3844         Value *V = Worklist.pop_back_val();
3845         for (User *U : V->users()) {
3846           if (auto *I = dyn_cast<Instruction>(U)) {
3847             Function *P = I->getFunction();
3848             if (P != &F)
3849               BlockAddressUsers.insert(P);
3850           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3851                      Visited.insert(U).second)
3852             Worklist.push_back(U);
3853         }
3854       }
3855     }
3856   }
3857 
3858   if (!BlockAddressUsers.empty()) {
3859     Vals.resize(BlockAddressUsers.size());
3860     for (auto I : llvm::enumerate(BlockAddressUsers))
3861       Vals[I.index()] = VE.getValueID(I.value());
3862     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3863     Vals.clear();
3864   }
3865 
3866   // Emit names for all the instructions etc.
3867   if (auto *Symtab = F.getValueSymbolTable())
3868     writeFunctionLevelValueSymbolTable(*Symtab);
3869 
3870   if (NeedsMetadataAttachment)
3871     writeFunctionMetadataAttachment(F);
3872   if (VE.shouldPreserveUseListOrder())
3873     writeUseListBlock(&F);
3874   VE.purgeFunction();
3875   Stream.ExitBlock();
3876 }
3877 
3878 // Emit blockinfo, which defines the standard abbreviations etc.
3879 void ModuleBitcodeWriter::writeBlockInfo() {
3880   // We only want to emit block info records for blocks that have multiple
3881   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3882   // Other blocks can define their abbrevs inline.
3883   Stream.EnterBlockInfoBlock();
3884 
3885   // Encode type indices using fixed size based on number of types.
3886   BitCodeAbbrevOp TypeAbbrevOp(BitCodeAbbrevOp::Fixed,
3887                                VE.computeBitsRequiredForTypeIndices());
3888   // Encode value indices as 6-bit VBR.
3889   BitCodeAbbrevOp ValAbbrevOp(BitCodeAbbrevOp::VBR, 6);
3890 
3891   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3892     auto Abbv = std::make_shared<BitCodeAbbrev>();
3893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3895     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3897     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3898         VST_ENTRY_8_ABBREV)
3899       llvm_unreachable("Unexpected abbrev ordering!");
3900   }
3901 
3902   { // 7-bit fixed width VST_CODE_ENTRY strings.
3903     auto Abbv = std::make_shared<BitCodeAbbrev>();
3904     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3905     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3906     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3907     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3908     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3909         VST_ENTRY_7_ABBREV)
3910       llvm_unreachable("Unexpected abbrev ordering!");
3911   }
3912   { // 6-bit char6 VST_CODE_ENTRY strings.
3913     auto Abbv = std::make_shared<BitCodeAbbrev>();
3914     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3915     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3916     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3917     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3918     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3919         VST_ENTRY_6_ABBREV)
3920       llvm_unreachable("Unexpected abbrev ordering!");
3921   }
3922   { // 6-bit char6 VST_CODE_BBENTRY strings.
3923     auto Abbv = std::make_shared<BitCodeAbbrev>();
3924     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3925     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3926     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3928     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3929         VST_BBENTRY_6_ABBREV)
3930       llvm_unreachable("Unexpected abbrev ordering!");
3931   }
3932 
3933   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3934     auto Abbv = std::make_shared<BitCodeAbbrev>();
3935     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3936     Abbv->Add(TypeAbbrevOp);
3937     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3938         CONSTANTS_SETTYPE_ABBREV)
3939       llvm_unreachable("Unexpected abbrev ordering!");
3940   }
3941 
3942   { // INTEGER abbrev for CONSTANTS_BLOCK.
3943     auto Abbv = std::make_shared<BitCodeAbbrev>();
3944     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3945     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3946     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3947         CONSTANTS_INTEGER_ABBREV)
3948       llvm_unreachable("Unexpected abbrev ordering!");
3949   }
3950 
3951   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3952     auto Abbv = std::make_shared<BitCodeAbbrev>();
3953     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3954     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3955     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3956                               VE.computeBitsRequiredForTypeIndices()));
3957     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3958 
3959     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3960         CONSTANTS_CE_CAST_Abbrev)
3961       llvm_unreachable("Unexpected abbrev ordering!");
3962   }
3963   { // NULL abbrev for CONSTANTS_BLOCK.
3964     auto Abbv = std::make_shared<BitCodeAbbrev>();
3965     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3966     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3967         CONSTANTS_NULL_Abbrev)
3968       llvm_unreachable("Unexpected abbrev ordering!");
3969   }
3970 
3971   // FIXME: This should only use space for first class types!
3972 
3973   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3974     auto Abbv = std::make_shared<BitCodeAbbrev>();
3975     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3976     Abbv->Add(ValAbbrevOp); // Ptr
3977     Abbv->Add(TypeAbbrevOp); // dest ty
3978     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3979     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3980     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3981         FUNCTION_INST_LOAD_ABBREV)
3982       llvm_unreachable("Unexpected abbrev ordering!");
3983   }
3984   {
3985     auto Abbv = std::make_shared<BitCodeAbbrev>();
3986     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_STORE));
3987     Abbv->Add(ValAbbrevOp);                                // op1
3988     Abbv->Add(ValAbbrevOp);                                // op0
3989     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // align
3990     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3991     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3992         FUNCTION_INST_STORE_ABBREV)
3993       llvm_unreachable("Unexpected abbrev ordering!");
3994   }
3995   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3996     auto Abbv = std::make_shared<BitCodeAbbrev>();
3997     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3998     Abbv->Add(ValAbbrevOp); // LHS
3999     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4000     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4001         FUNCTION_INST_UNOP_ABBREV)
4002       llvm_unreachable("Unexpected abbrev ordering!");
4003   }
4004   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
4005     auto Abbv = std::make_shared<BitCodeAbbrev>();
4006     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
4007     Abbv->Add(ValAbbrevOp); // LHS
4008     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4009     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
4010     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4011         FUNCTION_INST_UNOP_FLAGS_ABBREV)
4012       llvm_unreachable("Unexpected abbrev ordering!");
4013   }
4014   { // INST_BINOP abbrev for FUNCTION_BLOCK.
4015     auto Abbv = std::make_shared<BitCodeAbbrev>();
4016     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
4017     Abbv->Add(ValAbbrevOp); // LHS
4018     Abbv->Add(ValAbbrevOp); // RHS
4019     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4020     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4021         FUNCTION_INST_BINOP_ABBREV)
4022       llvm_unreachable("Unexpected abbrev ordering!");
4023   }
4024   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
4025     auto Abbv = std::make_shared<BitCodeAbbrev>();
4026     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
4027     Abbv->Add(ValAbbrevOp); // LHS
4028     Abbv->Add(ValAbbrevOp); // RHS
4029     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4030     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
4031     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4032         FUNCTION_INST_BINOP_FLAGS_ABBREV)
4033       llvm_unreachable("Unexpected abbrev ordering!");
4034   }
4035   { // INST_CAST abbrev for FUNCTION_BLOCK.
4036     auto Abbv = std::make_shared<BitCodeAbbrev>();
4037     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
4038     Abbv->Add(ValAbbrevOp); // OpVal
4039     Abbv->Add(TypeAbbrevOp); // dest ty
4040     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4041     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4042         FUNCTION_INST_CAST_ABBREV)
4043       llvm_unreachable("Unexpected abbrev ordering!");
4044   }
4045   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
4046     auto Abbv = std::make_shared<BitCodeAbbrev>();
4047     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
4048     Abbv->Add(ValAbbrevOp); // OpVal
4049     Abbv->Add(TypeAbbrevOp); // dest ty
4050     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
4051     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
4052     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4053         FUNCTION_INST_CAST_FLAGS_ABBREV)
4054       llvm_unreachable("Unexpected abbrev ordering!");
4055   }
4056 
4057   { // INST_RET abbrev for FUNCTION_BLOCK.
4058     auto Abbv = std::make_shared<BitCodeAbbrev>();
4059     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
4060     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4061         FUNCTION_INST_RET_VOID_ABBREV)
4062       llvm_unreachable("Unexpected abbrev ordering!");
4063   }
4064   { // INST_RET abbrev for FUNCTION_BLOCK.
4065     auto Abbv = std::make_shared<BitCodeAbbrev>();
4066     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
4067     Abbv->Add(ValAbbrevOp);
4068     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4069         FUNCTION_INST_RET_VAL_ABBREV)
4070       llvm_unreachable("Unexpected abbrev ordering!");
4071   }
4072   {
4073     auto Abbv = std::make_shared<BitCodeAbbrev>();
4074     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BR));
4075     // TODO: Use different abbrev for absolute value reference (succ0)?
4076     Abbv->Add(ValAbbrevOp); // succ0
4077     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4078         FUNCTION_INST_BR_UNCOND_ABBREV)
4079       llvm_unreachable("Unexpected abbrev ordering!");
4080   }
4081   {
4082     auto Abbv = std::make_shared<BitCodeAbbrev>();
4083     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BR));
4084     // TODO: Use different abbrev for absolute value references (succ0, succ1)?
4085     Abbv->Add(ValAbbrevOp); // succ0
4086     Abbv->Add(ValAbbrevOp); // succ1
4087     Abbv->Add(ValAbbrevOp); // cond
4088     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4089         FUNCTION_INST_BR_COND_ABBREV)
4090       llvm_unreachable("Unexpected abbrev ordering!");
4091   }
4092   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
4093     auto Abbv = std::make_shared<BitCodeAbbrev>();
4094     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
4095     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4096         FUNCTION_INST_UNREACHABLE_ABBREV)
4097       llvm_unreachable("Unexpected abbrev ordering!");
4098   }
4099   {
4100     auto Abbv = std::make_shared<BitCodeAbbrev>();
4101     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
4102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); // flags
4103     Abbv->Add(TypeAbbrevOp); // dest ty
4104     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4105     Abbv->Add(ValAbbrevOp);
4106     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4107         FUNCTION_INST_GEP_ABBREV)
4108       llvm_unreachable("Unexpected abbrev ordering!");
4109   }
4110   {
4111     auto Abbv = std::make_shared<BitCodeAbbrev>();
4112     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CMP2));
4113     Abbv->Add(ValAbbrevOp);                                // op0
4114     Abbv->Add(ValAbbrevOp);                                // op1
4115     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // pred
4116     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4117         FUNCTION_INST_CMP_ABBREV)
4118       llvm_unreachable("Unexpected abbrev ordering!");
4119   }
4120   {
4121     auto Abbv = std::make_shared<BitCodeAbbrev>();
4122     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CMP2));
4123     Abbv->Add(ValAbbrevOp);                                // op0
4124     Abbv->Add(ValAbbrevOp);                                // op1
4125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 6)); // pred
4126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
4127     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4128         FUNCTION_INST_CMP_FLAGS_ABBREV)
4129       llvm_unreachable("Unexpected abbrev ordering!");
4130   }
4131   {
4132     auto Abbv = std::make_shared<BitCodeAbbrev>();
4133     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE));
4134     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // dbgloc
4135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // var
4136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // expr
4137     Abbv->Add(ValAbbrevOp); // val
4138     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4139         FUNCTION_DEBUG_RECORD_VALUE_ABBREV)
4140       llvm_unreachable("Unexpected abbrev ordering! 1");
4141   }
4142   {
4143     auto Abbv = std::make_shared<BitCodeAbbrev>();
4144     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_LOC));
4145     // NOTE: No IsDistinct field for FUNC_CODE_DEBUG_LOC.
4146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
4151     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Atom group.
4152     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 3)); // Atom rank.
4153     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
4154         FUNCTION_DEBUG_LOC_ABBREV)
4155       llvm_unreachable("Unexpected abbrev ordering!");
4156   }
4157   Stream.ExitBlock();
4158 }
4159 
4160 /// Write the module path strings, currently only used when generating
4161 /// a combined index file.
4162 void IndexBitcodeWriter::writeModStrings() {
4163   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
4164 
4165   // TODO: See which abbrev sizes we actually need to emit
4166 
4167   // 8-bit fixed-width MST_ENTRY strings.
4168   auto Abbv = std::make_shared<BitCodeAbbrev>();
4169   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
4173   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
4174 
4175   // 7-bit fixed width MST_ENTRY strings.
4176   Abbv = std::make_shared<BitCodeAbbrev>();
4177   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
4181   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
4182 
4183   // 6-bit char6 MST_ENTRY strings.
4184   Abbv = std::make_shared<BitCodeAbbrev>();
4185   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4189   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
4190 
4191   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
4192   Abbv = std::make_shared<BitCodeAbbrev>();
4193   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4199   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
4200 
4201   SmallVector<unsigned, 64> Vals;
4202   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
4203     StringRef Key = MPSE.getKey();
4204     const auto &Hash = MPSE.getValue();
4205     StringEncoding Bits = getStringEncoding(Key);
4206     unsigned AbbrevToUse = Abbrev8Bit;
4207     if (Bits == SE_Char6)
4208       AbbrevToUse = Abbrev6Bit;
4209     else if (Bits == SE_Fixed7)
4210       AbbrevToUse = Abbrev7Bit;
4211 
4212     auto ModuleId = ModuleIdMap.size();
4213     ModuleIdMap[Key] = ModuleId;
4214     Vals.push_back(ModuleId);
4215     Vals.append(Key.begin(), Key.end());
4216 
4217     // Emit the finished record.
4218     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
4219 
4220     // Emit an optional hash for the module now
4221     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
4222       Vals.assign(Hash.begin(), Hash.end());
4223       // Emit the hash record.
4224       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
4225     }
4226 
4227     Vals.clear();
4228   });
4229   Stream.ExitBlock();
4230 }
4231 
4232 /// Write the function type metadata related records that need to appear before
4233 /// a function summary entry (whether per-module or combined).
4234 template <typename Fn>
4235 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
4236                                              FunctionSummary *FS,
4237                                              Fn GetValueID) {
4238   if (!FS->type_tests().empty())
4239     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
4240 
4241   SmallVector<uint64_t, 64> Record;
4242 
4243   auto WriteVFuncIdVec = [&](uint64_t Ty,
4244                              ArrayRef<FunctionSummary::VFuncId> VFs) {
4245     if (VFs.empty())
4246       return;
4247     Record.clear();
4248     for (auto &VF : VFs) {
4249       Record.push_back(VF.GUID);
4250       Record.push_back(VF.Offset);
4251     }
4252     Stream.EmitRecord(Ty, Record);
4253   };
4254 
4255   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
4256                   FS->type_test_assume_vcalls());
4257   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
4258                   FS->type_checked_load_vcalls());
4259 
4260   auto WriteConstVCallVec = [&](uint64_t Ty,
4261                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
4262     for (auto &VC : VCs) {
4263       Record.clear();
4264       Record.push_back(VC.VFunc.GUID);
4265       Record.push_back(VC.VFunc.Offset);
4266       llvm::append_range(Record, VC.Args);
4267       Stream.EmitRecord(Ty, Record);
4268     }
4269   };
4270 
4271   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
4272                      FS->type_test_assume_const_vcalls());
4273   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
4274                      FS->type_checked_load_const_vcalls());
4275 
4276   auto WriteRange = [&](ConstantRange Range) {
4277     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
4278     assert(Range.getLower().getNumWords() == 1);
4279     assert(Range.getUpper().getNumWords() == 1);
4280     emitSignedInt64(Record, *Range.getLower().getRawData());
4281     emitSignedInt64(Record, *Range.getUpper().getRawData());
4282   };
4283 
4284   if (!FS->paramAccesses().empty()) {
4285     Record.clear();
4286     for (auto &Arg : FS->paramAccesses()) {
4287       size_t UndoSize = Record.size();
4288       Record.push_back(Arg.ParamNo);
4289       WriteRange(Arg.Use);
4290       Record.push_back(Arg.Calls.size());
4291       for (auto &Call : Arg.Calls) {
4292         Record.push_back(Call.ParamNo);
4293         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
4294         if (!ValueID) {
4295           // If ValueID is unknown we can't drop just this call, we must drop
4296           // entire parameter.
4297           Record.resize(UndoSize);
4298           break;
4299         }
4300         Record.push_back(*ValueID);
4301         WriteRange(Call.Offsets);
4302       }
4303     }
4304     if (!Record.empty())
4305       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
4306   }
4307 }
4308 
4309 /// Collect type IDs from type tests used by function.
4310 static void
4311 getReferencedTypeIds(FunctionSummary *FS,
4312                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
4313   if (!FS->type_tests().empty())
4314     for (auto &TT : FS->type_tests())
4315       ReferencedTypeIds.insert(TT);
4316 
4317   auto GetReferencedTypesFromVFuncIdVec =
4318       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
4319         for (auto &VF : VFs)
4320           ReferencedTypeIds.insert(VF.GUID);
4321       };
4322 
4323   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
4324   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
4325 
4326   auto GetReferencedTypesFromConstVCallVec =
4327       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
4328         for (auto &VC : VCs)
4329           ReferencedTypeIds.insert(VC.VFunc.GUID);
4330       };
4331 
4332   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
4333   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
4334 }
4335 
4336 static void writeWholeProgramDevirtResolutionByArg(
4337     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
4338     const WholeProgramDevirtResolution::ByArg &ByArg) {
4339   NameVals.push_back(args.size());
4340   llvm::append_range(NameVals, args);
4341 
4342   NameVals.push_back(ByArg.TheKind);
4343   NameVals.push_back(ByArg.Info);
4344   NameVals.push_back(ByArg.Byte);
4345   NameVals.push_back(ByArg.Bit);
4346 }
4347 
4348 static void writeWholeProgramDevirtResolution(
4349     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4350     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
4351   NameVals.push_back(Id);
4352 
4353   NameVals.push_back(Wpd.TheKind);
4354   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
4355   NameVals.push_back(Wpd.SingleImplName.size());
4356 
4357   NameVals.push_back(Wpd.ResByArg.size());
4358   for (auto &A : Wpd.ResByArg)
4359     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
4360 }
4361 
4362 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
4363                                      StringTableBuilder &StrtabBuilder,
4364                                      StringRef Id,
4365                                      const TypeIdSummary &Summary) {
4366   NameVals.push_back(StrtabBuilder.add(Id));
4367   NameVals.push_back(Id.size());
4368 
4369   NameVals.push_back(Summary.TTRes.TheKind);
4370   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
4371   NameVals.push_back(Summary.TTRes.AlignLog2);
4372   NameVals.push_back(Summary.TTRes.SizeM1);
4373   NameVals.push_back(Summary.TTRes.BitMask);
4374   NameVals.push_back(Summary.TTRes.InlineBits);
4375 
4376   for (auto &W : Summary.WPDRes)
4377     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
4378                                       W.second);
4379 }
4380 
4381 static void writeTypeIdCompatibleVtableSummaryRecord(
4382     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4383     StringRef Id, const TypeIdCompatibleVtableInfo &Summary,
4384     ValueEnumerator &VE) {
4385   NameVals.push_back(StrtabBuilder.add(Id));
4386   NameVals.push_back(Id.size());
4387 
4388   for (auto &P : Summary) {
4389     NameVals.push_back(P.AddressPointOffset);
4390     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
4391   }
4392 }
4393 
4394 // Adds the allocation contexts to the CallStacks map. We simply use the
4395 // size at the time the context was added as the CallStackId. This works because
4396 // when we look up the call stacks later on we process the function summaries
4397 // and their allocation records in the same exact order.
4398 static void collectMemProfCallStacks(
4399     FunctionSummary *FS, std::function<LinearFrameId(unsigned)> GetStackIndex,
4400     MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> &CallStacks) {
4401   // The interfaces in ProfileData/MemProf.h use a type alias for a stack frame
4402   // id offset into the index of the full stack frames. The ModuleSummaryIndex
4403   // currently uses unsigned. Make sure these stay in sync.
4404   static_assert(std::is_same_v<LinearFrameId, unsigned>);
4405   for (auto &AI : FS->allocs()) {
4406     for (auto &MIB : AI.MIBs) {
4407       SmallVector<unsigned> StackIdIndices;
4408       StackIdIndices.reserve(MIB.StackIdIndices.size());
4409       for (auto Id : MIB.StackIdIndices)
4410         StackIdIndices.push_back(GetStackIndex(Id));
4411       // The CallStackId is the size at the time this context was inserted.
4412       CallStacks.insert({CallStacks.size(), StackIdIndices});
4413     }
4414   }
4415 }
4416 
4417 // Build the radix tree from the accumulated CallStacks, write out the resulting
4418 // linearized radix tree array, and return the map of call stack positions into
4419 // this array for use when writing the allocation records. The returned map is
4420 // indexed by a CallStackId which in this case is implicitly determined by the
4421 // order of function summaries and their allocation infos being written.
4422 static DenseMap<CallStackId, LinearCallStackId> writeMemoryProfileRadixTree(
4423     MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> &&CallStacks,
4424     BitstreamWriter &Stream, unsigned RadixAbbrev) {
4425   assert(!CallStacks.empty());
4426   DenseMap<unsigned, FrameStat> FrameHistogram =
4427       computeFrameHistogram<LinearFrameId>(CallStacks);
4428   CallStackRadixTreeBuilder<LinearFrameId> Builder;
4429   // We don't need a MemProfFrameIndexes map as we have already converted the
4430   // full stack id hash to a linear offset into the StackIds array.
4431   Builder.build(std::move(CallStacks), /*MemProfFrameIndexes=*/nullptr,
4432                 FrameHistogram);
4433   Stream.EmitRecord(bitc::FS_CONTEXT_RADIX_TREE_ARRAY, Builder.getRadixArray(),
4434                     RadixAbbrev);
4435   return Builder.takeCallStackPos();
4436 }
4437 
4438 static void writeFunctionHeapProfileRecords(
4439     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
4440     unsigned AllocAbbrev, unsigned ContextIdAbbvId, bool PerModule,
4441     std::function<unsigned(const ValueInfo &VI)> GetValueID,
4442     std::function<unsigned(unsigned)> GetStackIndex,
4443     bool WriteContextSizeInfoIndex,
4444     DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
4445     CallStackId &CallStackCount) {
4446   SmallVector<uint64_t> Record;
4447 
4448   for (auto &CI : FS->callsites()) {
4449     Record.clear();
4450     // Per module callsite clones should always have a single entry of
4451     // value 0.
4452     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
4453     Record.push_back(GetValueID(CI.Callee));
4454     if (!PerModule) {
4455       Record.push_back(CI.StackIdIndices.size());
4456       Record.push_back(CI.Clones.size());
4457     }
4458     for (auto Id : CI.StackIdIndices)
4459       Record.push_back(GetStackIndex(Id));
4460     if (!PerModule)
4461       llvm::append_range(Record, CI.Clones);
4462     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4463                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4464                       Record, CallsiteAbbrev);
4465   }
4466 
4467   for (auto &AI : FS->allocs()) {
4468     Record.clear();
4469     // Per module alloc versions should always have a single entry of
4470     // value 0.
4471     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4472     Record.push_back(AI.MIBs.size());
4473     if (!PerModule)
4474       Record.push_back(AI.Versions.size());
4475     for (auto &MIB : AI.MIBs) {
4476       Record.push_back((uint8_t)MIB.AllocType);
4477       // The per-module summary always needs to include the alloc context, as we
4478       // use it during the thin link. For the combined index it is optional (see
4479       // comments where CombinedIndexMemProfContext is defined).
4480       if (PerModule || CombinedIndexMemProfContext) {
4481         // Record the index into the radix tree array for this context.
4482         assert(CallStackCount <= CallStackPos.size());
4483         Record.push_back(CallStackPos[CallStackCount++]);
4484       }
4485     }
4486     if (!PerModule)
4487       llvm::append_range(Record, AI.Versions);
4488     assert(AI.ContextSizeInfos.empty() ||
4489            AI.ContextSizeInfos.size() == AI.MIBs.size());
4490     // Optionally emit the context size information if it exists.
4491     if (WriteContextSizeInfoIndex && !AI.ContextSizeInfos.empty()) {
4492       // The abbreviation id for the context ids record should have been created
4493       // if we are emitting the per-module index, which is where we write this
4494       // info.
4495       assert(ContextIdAbbvId);
4496       SmallVector<uint32_t> ContextIds;
4497       // At least one context id per ContextSizeInfos entry (MIB), broken into 2
4498       // halves.
4499       ContextIds.reserve(AI.ContextSizeInfos.size() * 2);
4500       for (auto &Infos : AI.ContextSizeInfos) {
4501         Record.push_back(Infos.size());
4502         for (auto [FullStackId, TotalSize] : Infos) {
4503           // The context ids are emitted separately as a fixed width array,
4504           // which is more efficient than a VBR given that these hashes are
4505           // typically close to 64-bits. The max fixed width entry is 32 bits so
4506           // it is split into 2.
4507           ContextIds.push_back(static_cast<uint32_t>(FullStackId >> 32));
4508           ContextIds.push_back(static_cast<uint32_t>(FullStackId));
4509           Record.push_back(TotalSize);
4510         }
4511       }
4512       // The context ids are expected by the reader to immediately precede the
4513       // associated alloc info record.
4514       Stream.EmitRecord(bitc::FS_ALLOC_CONTEXT_IDS, ContextIds,
4515                         ContextIdAbbvId);
4516     }
4517     Stream.EmitRecord(PerModule
4518                           ? bitc::FS_PERMODULE_ALLOC_INFO
4519                           : (CombinedIndexMemProfContext
4520                                  ? bitc::FS_COMBINED_ALLOC_INFO
4521                                  : bitc::FS_COMBINED_ALLOC_INFO_NO_CONTEXT),
4522                       Record, AllocAbbrev);
4523   }
4524 }
4525 
4526 // Helper to emit a single function summary record.
4527 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4528     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4529     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4530     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4531     unsigned AllocAbbrev, unsigned ContextIdAbbvId, const Function &F,
4532     DenseMap<CallStackId, LinearCallStackId> &CallStackPos,
4533     CallStackId &CallStackCount) {
4534   NameVals.push_back(ValueID);
4535 
4536   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4537 
4538   writeFunctionTypeMetadataRecords(
4539       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4540         return {VE.getValueID(VI.getValue())};
4541       });
4542 
4543   writeFunctionHeapProfileRecords(
4544       Stream, FS, CallsiteAbbrev, AllocAbbrev, ContextIdAbbvId,
4545       /*PerModule*/ true,
4546       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4547       /*GetStackIndex*/ [&](unsigned I) { return I; },
4548       /*WriteContextSizeInfoIndex*/ true, CallStackPos, CallStackCount);
4549 
4550   auto SpecialRefCnts = FS->specialRefCounts();
4551   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4552   NameVals.push_back(FS->instCount());
4553   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4554   NameVals.push_back(FS->refs().size());
4555   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4556   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4557 
4558   for (auto &RI : FS->refs())
4559     NameVals.push_back(getValueId(RI));
4560 
4561   const bool UseRelBFRecord =
4562       WriteRelBFToSummary && !F.hasProfileData() &&
4563       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4564   for (auto &ECI : FS->calls()) {
4565     NameVals.push_back(getValueId(ECI.first));
4566     if (UseRelBFRecord)
4567       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4568     else
4569       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4570   }
4571 
4572   unsigned FSAbbrev =
4573       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4574   unsigned Code =
4575       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4576 
4577   // Emit the finished record.
4578   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4579   NameVals.clear();
4580 }
4581 
4582 // Collect the global value references in the given variable's initializer,
4583 // and emit them in a summary record.
4584 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4585     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4586     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4587   auto VI = Index->getValueInfo(V.getGUID());
4588   if (!VI || VI.getSummaryList().empty()) {
4589     // Only declarations should not have a summary (a declaration might however
4590     // have a summary if the def was in module level asm).
4591     assert(V.isDeclaration());
4592     return;
4593   }
4594   auto *Summary = VI.getSummaryList()[0].get();
4595   NameVals.push_back(VE.getValueID(&V));
4596   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4597   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4598   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4599 
4600   auto VTableFuncs = VS->vTableFuncs();
4601   if (!VTableFuncs.empty())
4602     NameVals.push_back(VS->refs().size());
4603 
4604   unsigned SizeBeforeRefs = NameVals.size();
4605   for (auto &RI : VS->refs())
4606     NameVals.push_back(VE.getValueID(RI.getValue()));
4607   // Sort the refs for determinism output, the vector returned by FS->refs() has
4608   // been initialized from a DenseSet.
4609   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4610 
4611   if (VTableFuncs.empty())
4612     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4613                       FSModRefsAbbrev);
4614   else {
4615     // VTableFuncs pairs should already be sorted by offset.
4616     for (auto &P : VTableFuncs) {
4617       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4618       NameVals.push_back(P.VTableOffset);
4619     }
4620 
4621     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4622                       FSModVTableRefsAbbrev);
4623   }
4624   NameVals.clear();
4625 }
4626 
4627 /// Emit the per-module summary section alongside the rest of
4628 /// the module's bitcode.
4629 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4630   // By default we compile with ThinLTO if the module has a summary, but the
4631   // client can request full LTO with a module flag.
4632   bool IsThinLTO = true;
4633   if (auto *MD =
4634           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4635     IsThinLTO = MD->getZExtValue();
4636   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4637                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4638                        4);
4639 
4640   Stream.EmitRecord(
4641       bitc::FS_VERSION,
4642       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4643 
4644   // Write the index flags.
4645   uint64_t Flags = 0;
4646   // Bits 1-3 are set only in the combined index, skip them.
4647   if (Index->enableSplitLTOUnit())
4648     Flags |= 0x8;
4649   if (Index->hasUnifiedLTO())
4650     Flags |= 0x200;
4651 
4652   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4653 
4654   if (Index->begin() == Index->end()) {
4655     Stream.ExitBlock();
4656     return;
4657   }
4658 
4659   auto Abbv = std::make_shared<BitCodeAbbrev>();
4660   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4661   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4662   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4663   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4664   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4665   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4666 
4667   for (const auto &GVI : valueIds()) {
4668     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4669                       ArrayRef<uint32_t>{GVI.second,
4670                                          static_cast<uint32_t>(GVI.first >> 32),
4671                                          static_cast<uint32_t>(GVI.first)},
4672                       ValueGuidAbbrev);
4673   }
4674 
4675   if (!Index->stackIds().empty()) {
4676     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4677     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4678     // numids x stackid
4679     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4680     // The stack ids are hashes that are close to 64 bits in size, so emitting
4681     // as a pair of 32-bit fixed-width values is more efficient than a VBR.
4682     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4683     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4684     SmallVector<uint32_t> Vals;
4685     Vals.reserve(Index->stackIds().size() * 2);
4686     for (auto Id : Index->stackIds()) {
4687       Vals.push_back(static_cast<uint32_t>(Id >> 32));
4688       Vals.push_back(static_cast<uint32_t>(Id));
4689     }
4690     Stream.EmitRecord(bitc::FS_STACK_IDS, Vals, StackIdAbbvId);
4691   }
4692 
4693   unsigned ContextIdAbbvId = 0;
4694   if (metadataMayIncludeContextSizeInfo()) {
4695     // n x context id
4696     auto ContextIdAbbv = std::make_shared<BitCodeAbbrev>();
4697     ContextIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_ALLOC_CONTEXT_IDS));
4698     ContextIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4699     // The context ids are hashes that are close to 64 bits in size, so emitting
4700     // as a pair of 32-bit fixed-width values is more efficient than a VBR if we
4701     // are emitting them for all MIBs. Otherwise we use VBR to better compress 0
4702     // values that are expected to more frequently occur in an alloc's memprof
4703     // summary.
4704     if (metadataIncludesAllContextSizeInfo())
4705       ContextIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4706     else
4707       ContextIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4708     ContextIdAbbvId = Stream.EmitAbbrev(std::move(ContextIdAbbv));
4709   }
4710 
4711   // Abbrev for FS_PERMODULE_PROFILE.
4712   Abbv = std::make_shared<BitCodeAbbrev>();
4713   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4714   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4715   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4719   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4720   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4721   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4722   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4723   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4724   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4725 
4726   // Abbrev for FS_PERMODULE_RELBF.
4727   Abbv = std::make_shared<BitCodeAbbrev>();
4728   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4729   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4730   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4731   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4732   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4733   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4734   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4735   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4736   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4737   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4738   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4739   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4740 
4741   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4742   Abbv = std::make_shared<BitCodeAbbrev>();
4743   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4744   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4745   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4746   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4747   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4748   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4749 
4750   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4751   Abbv = std::make_shared<BitCodeAbbrev>();
4752   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4756   // numrefs x valueid, n x (valueid , offset)
4757   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4759   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4760 
4761   // Abbrev for FS_ALIAS.
4762   Abbv = std::make_shared<BitCodeAbbrev>();
4763   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4764   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4765   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4766   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4767   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4768 
4769   // Abbrev for FS_TYPE_ID_METADATA
4770   Abbv = std::make_shared<BitCodeAbbrev>();
4771   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4772   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4773   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4774   // n x (valueid , offset)
4775   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4777   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4778 
4779   Abbv = std::make_shared<BitCodeAbbrev>();
4780   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4781   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4782   // n x stackidindex
4783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4785   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4786 
4787   Abbv = std::make_shared<BitCodeAbbrev>();
4788   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4790   // n x (alloc type, context radix tree index)
4791   // optional: nummib x (numcontext x total size)
4792   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4794   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4795 
4796   Abbv = std::make_shared<BitCodeAbbrev>();
4797   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
4798   // n x entry
4799   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4800   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4801   unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4802 
4803   // First walk through all the functions and collect the allocation contexts in
4804   // their associated summaries, for use in constructing a radix tree of
4805   // contexts. Note that we need to do this in the same order as the functions
4806   // are processed further below since the call stack positions in the resulting
4807   // radix tree array are identified based on this order.
4808   MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
4809   for (const Function &F : M) {
4810     // Summary emission does not support anonymous functions, they have to be
4811     // renamed using the anonymous function renaming pass.
4812     if (!F.hasName())
4813       report_fatal_error("Unexpected anonymous function when writing summary");
4814 
4815     ValueInfo VI = Index->getValueInfo(F.getGUID());
4816     if (!VI || VI.getSummaryList().empty()) {
4817       // Only declarations should not have a summary (a declaration might
4818       // however have a summary if the def was in module level asm).
4819       assert(F.isDeclaration());
4820       continue;
4821     }
4822     auto *Summary = VI.getSummaryList()[0].get();
4823     FunctionSummary *FS = cast<FunctionSummary>(Summary);
4824     collectMemProfCallStacks(
4825         FS, /*GetStackIndex*/ [](unsigned I) { return I; }, CallStacks);
4826   }
4827   // Finalize the radix tree, write it out, and get the map of positions in the
4828   // linearized tree array.
4829   DenseMap<CallStackId, LinearCallStackId> CallStackPos;
4830   if (!CallStacks.empty()) {
4831     CallStackPos =
4832         writeMemoryProfileRadixTree(std::move(CallStacks), Stream, RadixAbbrev);
4833   }
4834 
4835   // Keep track of the current index into the CallStackPos map.
4836   CallStackId CallStackCount = 0;
4837 
4838   SmallVector<uint64_t, 64> NameVals;
4839   // Iterate over the list of functions instead of the Index to
4840   // ensure the ordering is stable.
4841   for (const Function &F : M) {
4842     // Summary emission does not support anonymous functions, they have to
4843     // renamed using the anonymous function renaming pass.
4844     if (!F.hasName())
4845       report_fatal_error("Unexpected anonymous function when writing summary");
4846 
4847     ValueInfo VI = Index->getValueInfo(F.getGUID());
4848     if (!VI || VI.getSummaryList().empty()) {
4849       // Only declarations should not have a summary (a declaration might
4850       // however have a summary if the def was in module level asm).
4851       assert(F.isDeclaration());
4852       continue;
4853     }
4854     auto *Summary = VI.getSummaryList()[0].get();
4855     writePerModuleFunctionSummaryRecord(
4856         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4857         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, ContextIdAbbvId, F,
4858         CallStackPos, CallStackCount);
4859   }
4860 
4861   // Capture references from GlobalVariable initializers, which are outside
4862   // of a function scope.
4863   for (const GlobalVariable &G : M.globals())
4864     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4865                                FSModVTableRefsAbbrev);
4866 
4867   for (const GlobalAlias &A : M.aliases()) {
4868     auto *Aliasee = A.getAliaseeObject();
4869     // Skip ifunc and nameless functions which don't have an entry in the
4870     // summary.
4871     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4872       continue;
4873     auto AliasId = VE.getValueID(&A);
4874     auto AliaseeId = VE.getValueID(Aliasee);
4875     NameVals.push_back(AliasId);
4876     auto *Summary = Index->getGlobalValueSummary(A);
4877     AliasSummary *AS = cast<AliasSummary>(Summary);
4878     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4879     NameVals.push_back(AliaseeId);
4880     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4881     NameVals.clear();
4882   }
4883 
4884   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4885     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4886                                              S.second, VE);
4887     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4888                       TypeIdCompatibleVtableAbbrev);
4889     NameVals.clear();
4890   }
4891 
4892   if (Index->getBlockCount())
4893     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4894                       ArrayRef<uint64_t>{Index->getBlockCount()});
4895 
4896   Stream.ExitBlock();
4897 }
4898 
4899 /// Emit the combined summary section into the combined index file.
4900 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4901   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4902   Stream.EmitRecord(
4903       bitc::FS_VERSION,
4904       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4905 
4906   // Write the index flags.
4907   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4908 
4909   auto Abbv = std::make_shared<BitCodeAbbrev>();
4910   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4912   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4915   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4916 
4917   for (const auto &GVI : valueIds()) {
4918     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4919                       ArrayRef<uint32_t>{GVI.second,
4920                                          static_cast<uint32_t>(GVI.first >> 32),
4921                                          static_cast<uint32_t>(GVI.first)},
4922                       ValueGuidAbbrev);
4923   }
4924 
4925   // Write the stack ids used by this index, which will be a subset of those in
4926   // the full index in the case of distributed indexes.
4927   if (!StackIds.empty()) {
4928     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4929     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4930     // numids x stackid
4931     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4932     // The stack ids are hashes that are close to 64 bits in size, so emitting
4933     // as a pair of 32-bit fixed-width values is more efficient than a VBR.
4934     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4935     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4936     SmallVector<uint32_t> Vals;
4937     Vals.reserve(StackIds.size() * 2);
4938     for (auto Id : StackIds) {
4939       Vals.push_back(static_cast<uint32_t>(Id >> 32));
4940       Vals.push_back(static_cast<uint32_t>(Id));
4941     }
4942     Stream.EmitRecord(bitc::FS_STACK_IDS, Vals, StackIdAbbvId);
4943   }
4944 
4945   // Abbrev for FS_COMBINED_PROFILE.
4946   Abbv = std::make_shared<BitCodeAbbrev>();
4947   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4957   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4960   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4961 
4962   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4963   Abbv = std::make_shared<BitCodeAbbrev>();
4964   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4970   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4971 
4972   // Abbrev for FS_COMBINED_ALIAS.
4973   Abbv = std::make_shared<BitCodeAbbrev>();
4974   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4979   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4980 
4981   Abbv = std::make_shared<BitCodeAbbrev>();
4982   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4986   // numstackindices x stackidindex, numver x version
4987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4989   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4990 
4991   Abbv = std::make_shared<BitCodeAbbrev>();
4992   Abbv->Add(BitCodeAbbrevOp(CombinedIndexMemProfContext
4993                                 ? bitc::FS_COMBINED_ALLOC_INFO
4994                                 : bitc::FS_COMBINED_ALLOC_INFO_NO_CONTEXT));
4995   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4997   // nummib x (alloc type, context radix tree index),
4998   // numver x version
4999   // optional: nummib x total size
5000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
5002   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5003 
5004   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
5005     if (DecSummaries == nullptr)
5006       return false;
5007     return DecSummaries->count(GVS);
5008   };
5009 
5010   // The aliases are emitted as a post-pass, and will point to the value
5011   // id of the aliasee. Save them in a vector for post-processing.
5012   SmallVector<AliasSummary *, 64> Aliases;
5013 
5014   // Save the value id for each summary for alias emission.
5015   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
5016 
5017   SmallVector<uint64_t, 64> NameVals;
5018 
5019   // Set that will be populated during call to writeFunctionTypeMetadataRecords
5020   // with the type ids referenced by this index file.
5021   std::set<GlobalValue::GUID> ReferencedTypeIds;
5022 
5023   // For local linkage, we also emit the original name separately
5024   // immediately after the record.
5025   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
5026     // We don't need to emit the original name if we are writing the index for
5027     // distributed backends (in which case ModuleToSummariesForIndex is
5028     // non-null). The original name is only needed during the thin link, since
5029     // for SamplePGO the indirect call targets for local functions have
5030     // have the original name annotated in profile.
5031     // Continue to emit it when writing out the entire combined index, which is
5032     // used in testing the thin link via llvm-lto.
5033     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
5034       return;
5035     NameVals.push_back(S.getOriginalName());
5036     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
5037     NameVals.clear();
5038   };
5039 
5040   DenseMap<CallStackId, LinearCallStackId> CallStackPos;
5041   if (CombinedIndexMemProfContext) {
5042     Abbv = std::make_shared<BitCodeAbbrev>();
5043     Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
5044     // n x entry
5045     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5046     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
5047     unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5048 
5049     // First walk through all the functions and collect the allocation contexts
5050     // in their associated summaries, for use in constructing a radix tree of
5051     // contexts. Note that we need to do this in the same order as the functions
5052     // are processed further below since the call stack positions in the
5053     // resulting radix tree array are identified based on this order.
5054     MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
5055     forEachSummary([&](GVInfo I, bool IsAliasee) {
5056       // Don't collect this when invoked for an aliasee, as it is not needed for
5057       // the alias summary. If the aliasee is to be imported, we will invoke
5058       // this separately with IsAliasee=false.
5059       if (IsAliasee)
5060         return;
5061       GlobalValueSummary *S = I.second;
5062       assert(S);
5063       auto *FS = dyn_cast<FunctionSummary>(S);
5064       if (!FS)
5065         return;
5066       collectMemProfCallStacks(
5067           FS,
5068           /*GetStackIndex*/
5069           [&](unsigned I) {
5070             // Get the corresponding index into the list of StackIds actually
5071             // being written for this combined index (which may be a subset in
5072             // the case of distributed indexes).
5073             assert(StackIdIndicesToIndex.contains(I));
5074             return StackIdIndicesToIndex[I];
5075           },
5076           CallStacks);
5077     });
5078     // Finalize the radix tree, write it out, and get the map of positions in
5079     // the linearized tree array.
5080     if (!CallStacks.empty()) {
5081       CallStackPos = writeMemoryProfileRadixTree(std::move(CallStacks), Stream,
5082                                                  RadixAbbrev);
5083     }
5084   }
5085 
5086   // Keep track of the current index into the CallStackPos map. Not used if
5087   // CombinedIndexMemProfContext is false.
5088   CallStackId CallStackCount = 0;
5089 
5090   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
5091   forEachSummary([&](GVInfo I, bool IsAliasee) {
5092     GlobalValueSummary *S = I.second;
5093     assert(S);
5094     DefOrUseGUIDs.insert(I.first);
5095     for (const ValueInfo &VI : S->refs())
5096       DefOrUseGUIDs.insert(VI.getGUID());
5097 
5098     auto ValueId = getValueId(I.first);
5099     assert(ValueId);
5100     SummaryToValueIdMap[S] = *ValueId;
5101 
5102     // If this is invoked for an aliasee, we want to record the above
5103     // mapping, but then not emit a summary entry (if the aliasee is
5104     // to be imported, we will invoke this separately with IsAliasee=false).
5105     if (IsAliasee)
5106       return;
5107 
5108     if (auto *AS = dyn_cast<AliasSummary>(S)) {
5109       // Will process aliases as a post-pass because the reader wants all
5110       // global to be loaded first.
5111       Aliases.push_back(AS);
5112       return;
5113     }
5114 
5115     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
5116       NameVals.push_back(*ValueId);
5117       assert(ModuleIdMap.count(VS->modulePath()));
5118       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
5119       NameVals.push_back(
5120           getEncodedGVSummaryFlags(VS->flags(), shouldImportValueAsDecl(VS)));
5121       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
5122       for (auto &RI : VS->refs()) {
5123         auto RefValueId = getValueId(RI.getGUID());
5124         if (!RefValueId)
5125           continue;
5126         NameVals.push_back(*RefValueId);
5127       }
5128 
5129       // Emit the finished record.
5130       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
5131                         FSModRefsAbbrev);
5132       NameVals.clear();
5133       MaybeEmitOriginalName(*S);
5134       return;
5135     }
5136 
5137     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
5138       if (!VI)
5139         return std::nullopt;
5140       return getValueId(VI.getGUID());
5141     };
5142 
5143     auto *FS = cast<FunctionSummary>(S);
5144     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
5145     getReferencedTypeIds(FS, ReferencedTypeIds);
5146 
5147     writeFunctionHeapProfileRecords(
5148         Stream, FS, CallsiteAbbrev, AllocAbbrev, /*ContextIdAbbvId*/ 0,
5149         /*PerModule*/ false,
5150         /*GetValueId*/
5151         [&](const ValueInfo &VI) -> unsigned {
5152           std::optional<unsigned> ValueID = GetValueId(VI);
5153           // This can happen in shared index files for distributed ThinLTO if
5154           // the callee function summary is not included. Record 0 which we
5155           // will have to deal with conservatively when doing any kind of
5156           // validation in the ThinLTO backends.
5157           if (!ValueID)
5158             return 0;
5159           return *ValueID;
5160         },
5161         /*GetStackIndex*/
5162         [&](unsigned I) {
5163           // Get the corresponding index into the list of StackIds actually
5164           // being written for this combined index (which may be a subset in
5165           // the case of distributed indexes).
5166           assert(StackIdIndicesToIndex.contains(I));
5167           return StackIdIndicesToIndex[I];
5168         },
5169         /*WriteContextSizeInfoIndex*/ false, CallStackPos, CallStackCount);
5170 
5171     NameVals.push_back(*ValueId);
5172     assert(ModuleIdMap.count(FS->modulePath()));
5173     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
5174     NameVals.push_back(
5175         getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
5176     NameVals.push_back(FS->instCount());
5177     NameVals.push_back(getEncodedFFlags(FS->fflags()));
5178     // TODO: Stop writing entry count and bump bitcode version.
5179     NameVals.push_back(0 /* EntryCount */);
5180 
5181     // Fill in below
5182     NameVals.push_back(0); // numrefs
5183     NameVals.push_back(0); // rorefcnt
5184     NameVals.push_back(0); // worefcnt
5185 
5186     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
5187     for (auto &RI : FS->refs()) {
5188       auto RefValueId = getValueId(RI.getGUID());
5189       if (!RefValueId)
5190         continue;
5191       NameVals.push_back(*RefValueId);
5192       if (RI.isReadOnly())
5193         RORefCnt++;
5194       else if (RI.isWriteOnly())
5195         WORefCnt++;
5196       Count++;
5197     }
5198     NameVals[6] = Count;
5199     NameVals[7] = RORefCnt;
5200     NameVals[8] = WORefCnt;
5201 
5202     for (auto &EI : FS->calls()) {
5203       // If this GUID doesn't have a value id, it doesn't have a function
5204       // summary and we don't need to record any calls to it.
5205       std::optional<unsigned> CallValueId = GetValueId(EI.first);
5206       if (!CallValueId)
5207         continue;
5208       NameVals.push_back(*CallValueId);
5209       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
5210     }
5211 
5212     // Emit the finished record.
5213     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
5214                       FSCallsProfileAbbrev);
5215     NameVals.clear();
5216     MaybeEmitOriginalName(*S);
5217   });
5218 
5219   for (auto *AS : Aliases) {
5220     auto AliasValueId = SummaryToValueIdMap[AS];
5221     assert(AliasValueId);
5222     NameVals.push_back(AliasValueId);
5223     assert(ModuleIdMap.count(AS->modulePath()));
5224     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
5225     NameVals.push_back(
5226         getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
5227     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
5228     assert(AliaseeValueId);
5229     NameVals.push_back(AliaseeValueId);
5230 
5231     // Emit the finished record.
5232     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
5233     NameVals.clear();
5234     MaybeEmitOriginalName(*AS);
5235 
5236     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
5237       getReferencedTypeIds(FS, ReferencedTypeIds);
5238   }
5239 
5240   SmallVector<StringRef, 4> Functions;
5241   auto EmitCfiFunctions = [&](const CfiFunctionIndex &CfiIndex,
5242                               bitc::GlobalValueSummarySymtabCodes Code) {
5243     if (CfiIndex.empty())
5244       return;
5245     for (GlobalValue::GUID GUID : DefOrUseGUIDs) {
5246       auto Defs = CfiIndex.forGuid(GUID);
5247       llvm::append_range(Functions, Defs);
5248     }
5249     if (Functions.empty())
5250       return;
5251     llvm::sort(Functions);
5252     for (const auto &S : Functions) {
5253       NameVals.push_back(StrtabBuilder.add(S));
5254       NameVals.push_back(S.size());
5255     }
5256     Stream.EmitRecord(Code, NameVals);
5257     NameVals.clear();
5258     Functions.clear();
5259   };
5260 
5261   EmitCfiFunctions(Index.cfiFunctionDefs(), bitc::FS_CFI_FUNCTION_DEFS);
5262   EmitCfiFunctions(Index.cfiFunctionDecls(), bitc::FS_CFI_FUNCTION_DECLS);
5263 
5264   // Walk the GUIDs that were referenced, and write the
5265   // corresponding type id records.
5266   for (auto &T : ReferencedTypeIds) {
5267     auto TidIter = Index.typeIds().equal_range(T);
5268     for (const auto &[GUID, TypeIdPair] : make_range(TidIter)) {
5269       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, TypeIdPair.first,
5270                                TypeIdPair.second);
5271       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
5272       NameVals.clear();
5273     }
5274   }
5275 
5276   if (Index.getBlockCount())
5277     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
5278                       ArrayRef<uint64_t>{Index.getBlockCount()});
5279 
5280   Stream.ExitBlock();
5281 }
5282 
5283 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
5284 /// current llvm version, and a record for the epoch number.
5285 static void writeIdentificationBlock(BitstreamWriter &Stream) {
5286   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
5287 
5288   // Write the "user readable" string identifying the bitcode producer
5289   auto Abbv = std::make_shared<BitCodeAbbrev>();
5290   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
5291   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5292   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
5293   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5294   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
5295                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
5296 
5297   // Write the epoch version
5298   Abbv = std::make_shared<BitCodeAbbrev>();
5299   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
5300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
5301   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5302   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
5303   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
5304   Stream.ExitBlock();
5305 }
5306 
5307 void ModuleBitcodeWriter::writeModuleHash(StringRef View) {
5308   // Emit the module's hash.
5309   // MODULE_CODE_HASH: [5*i32]
5310   if (GenerateHash) {
5311     uint32_t Vals[5];
5312     Hasher.update(ArrayRef<uint8_t>(
5313         reinterpret_cast<const uint8_t *>(View.data()), View.size()));
5314     std::array<uint8_t, 20> Hash = Hasher.result();
5315     for (int Pos = 0; Pos < 20; Pos += 4) {
5316       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
5317     }
5318 
5319     // Emit the finished record.
5320     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
5321 
5322     if (ModHash)
5323       // Save the written hash value.
5324       llvm::copy(Vals, std::begin(*ModHash));
5325   }
5326 }
5327 
5328 void ModuleBitcodeWriter::write() {
5329   writeIdentificationBlock(Stream);
5330 
5331   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5332   // We will want to write the module hash at this point. Block any flushing so
5333   // we can have access to the whole underlying data later.
5334   Stream.markAndBlockFlushing();
5335 
5336   writeModuleVersion();
5337 
5338   // Emit blockinfo, which defines the standard abbreviations etc.
5339   writeBlockInfo();
5340 
5341   // Emit information describing all of the types in the module.
5342   writeTypeTable();
5343 
5344   // Emit information about attribute groups.
5345   writeAttributeGroupTable();
5346 
5347   // Emit information about parameter attributes.
5348   writeAttributeTable();
5349 
5350   writeComdats();
5351 
5352   // Emit top-level description of module, including target triple, inline asm,
5353   // descriptors for global variables, and function prototype info.
5354   writeModuleInfo();
5355 
5356   // Emit constants.
5357   writeModuleConstants();
5358 
5359   // Emit metadata kind names.
5360   writeModuleMetadataKinds();
5361 
5362   // Emit metadata.
5363   writeModuleMetadata();
5364 
5365   // Emit module-level use-lists.
5366   if (VE.shouldPreserveUseListOrder())
5367     writeUseListBlock(nullptr);
5368 
5369   writeOperandBundleTags();
5370   writeSyncScopeNames();
5371 
5372   // Emit function bodies.
5373   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
5374   for (const Function &F : M)
5375     if (!F.isDeclaration())
5376       writeFunction(F, FunctionToBitcodeIndex);
5377 
5378   // Need to write after the above call to WriteFunction which populates
5379   // the summary information in the index.
5380   if (Index)
5381     writePerModuleGlobalValueSummary();
5382 
5383   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
5384 
5385   writeModuleHash(Stream.getMarkedBufferAndResumeFlushing());
5386 
5387   Stream.ExitBlock();
5388 }
5389 
5390 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
5391                                uint32_t &Position) {
5392   support::endian::write32le(&Buffer[Position], Value);
5393   Position += 4;
5394 }
5395 
5396 /// If generating a bc file on darwin, we have to emit a
5397 /// header and trailer to make it compatible with the system archiver.  To do
5398 /// this we emit the following header, and then emit a trailer that pads the
5399 /// file out to be a multiple of 16 bytes.
5400 ///
5401 /// struct bc_header {
5402 ///   uint32_t Magic;         // 0x0B17C0DE
5403 ///   uint32_t Version;       // Version, currently always 0.
5404 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
5405 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
5406 ///   uint32_t CPUType;       // CPU specifier.
5407 ///   ... potentially more later ...
5408 /// };
5409 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
5410                                          const Triple &TT) {
5411   unsigned CPUType = ~0U;
5412 
5413   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
5414   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
5415   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
5416   // specific constants here because they are implicitly part of the Darwin ABI.
5417   enum {
5418     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
5419     DARWIN_CPU_TYPE_X86        = 7,
5420     DARWIN_CPU_TYPE_ARM        = 12,
5421     DARWIN_CPU_TYPE_POWERPC    = 18
5422   };
5423 
5424   Triple::ArchType Arch = TT.getArch();
5425   if (Arch == Triple::x86_64)
5426     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
5427   else if (Arch == Triple::x86)
5428     CPUType = DARWIN_CPU_TYPE_X86;
5429   else if (Arch == Triple::ppc)
5430     CPUType = DARWIN_CPU_TYPE_POWERPC;
5431   else if (Arch == Triple::ppc64)
5432     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
5433   else if (Arch == Triple::arm || Arch == Triple::thumb)
5434     CPUType = DARWIN_CPU_TYPE_ARM;
5435 
5436   // Traditional Bitcode starts after header.
5437   assert(Buffer.size() >= BWH_HeaderSize &&
5438          "Expected header size to be reserved");
5439   unsigned BCOffset = BWH_HeaderSize;
5440   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
5441 
5442   // Write the magic and version.
5443   unsigned Position = 0;
5444   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
5445   writeInt32ToBuffer(0, Buffer, Position); // Version.
5446   writeInt32ToBuffer(BCOffset, Buffer, Position);
5447   writeInt32ToBuffer(BCSize, Buffer, Position);
5448   writeInt32ToBuffer(CPUType, Buffer, Position);
5449 
5450   // If the file is not a multiple of 16 bytes, insert dummy padding.
5451   while (Buffer.size() & 15)
5452     Buffer.push_back(0);
5453 }
5454 
5455 /// Helper to write the header common to all bitcode files.
5456 static void writeBitcodeHeader(BitstreamWriter &Stream) {
5457   // Emit the file header.
5458   Stream.Emit((unsigned)'B', 8);
5459   Stream.Emit((unsigned)'C', 8);
5460   Stream.Emit(0x0, 4);
5461   Stream.Emit(0xC, 4);
5462   Stream.Emit(0xE, 4);
5463   Stream.Emit(0xD, 4);
5464 }
5465 
5466 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
5467     : Stream(new BitstreamWriter(Buffer)) {
5468   writeBitcodeHeader(*Stream);
5469 }
5470 
5471 BitcodeWriter::BitcodeWriter(raw_ostream &FS)
5472     : Stream(new BitstreamWriter(FS, FlushThreshold)) {
5473   writeBitcodeHeader(*Stream);
5474 }
5475 
5476 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
5477 
5478 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
5479   Stream->EnterSubblock(Block, 3);
5480 
5481   auto Abbv = std::make_shared<BitCodeAbbrev>();
5482   Abbv->Add(BitCodeAbbrevOp(Record));
5483   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
5484   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
5485 
5486   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
5487 
5488   Stream->ExitBlock();
5489 }
5490 
5491 void BitcodeWriter::writeSymtab() {
5492   assert(!WroteStrtab && !WroteSymtab);
5493 
5494   // If any module has module-level inline asm, we will require a registered asm
5495   // parser for the target so that we can create an accurate symbol table for
5496   // the module.
5497   for (Module *M : Mods) {
5498     if (M->getModuleInlineAsm().empty())
5499       continue;
5500 
5501     std::string Err;
5502     const Triple TT(M->getTargetTriple());
5503     const Target *T = TargetRegistry::lookupTarget(TT, Err);
5504     if (!T || !T->hasMCAsmParser())
5505       return;
5506   }
5507 
5508   WroteSymtab = true;
5509   SmallVector<char, 0> Symtab;
5510   // The irsymtab::build function may be unable to create a symbol table if the
5511   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
5512   // table is not required for correctness, but we still want to be able to
5513   // write malformed modules to bitcode files, so swallow the error.
5514   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
5515     consumeError(std::move(E));
5516     return;
5517   }
5518 
5519   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
5520             {Symtab.data(), Symtab.size()});
5521 }
5522 
5523 void BitcodeWriter::writeStrtab() {
5524   assert(!WroteStrtab);
5525 
5526   std::vector<char> Strtab;
5527   StrtabBuilder.finalizeInOrder();
5528   Strtab.resize(StrtabBuilder.getSize());
5529   StrtabBuilder.write((uint8_t *)Strtab.data());
5530 
5531   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
5532             {Strtab.data(), Strtab.size()});
5533 
5534   WroteStrtab = true;
5535 }
5536 
5537 void BitcodeWriter::copyStrtab(StringRef Strtab) {
5538   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
5539   WroteStrtab = true;
5540 }
5541 
5542 void BitcodeWriter::writeModule(const Module &M,
5543                                 bool ShouldPreserveUseListOrder,
5544                                 const ModuleSummaryIndex *Index,
5545                                 bool GenerateHash, ModuleHash *ModHash) {
5546   assert(!WroteStrtab);
5547 
5548   // The Mods vector is used by irsymtab::build, which requires non-const
5549   // Modules in case it needs to materialize metadata. But the bitcode writer
5550   // requires that the module is materialized, so we can cast to non-const here,
5551   // after checking that it is in fact materialized.
5552   assert(M.isMaterialized());
5553   Mods.push_back(const_cast<Module *>(&M));
5554 
5555   ModuleBitcodeWriter ModuleWriter(M, StrtabBuilder, *Stream,
5556                                    ShouldPreserveUseListOrder, Index,
5557                                    GenerateHash, ModHash);
5558   ModuleWriter.write();
5559 }
5560 
5561 void BitcodeWriter::writeIndex(
5562     const ModuleSummaryIndex *Index,
5563     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5564     const GVSummaryPtrSet *DecSummaries) {
5565   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
5566                                  ModuleToSummariesForIndex);
5567   IndexWriter.write();
5568 }
5569 
5570 /// Write the specified module to the specified output stream.
5571 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
5572                               bool ShouldPreserveUseListOrder,
5573                               const ModuleSummaryIndex *Index,
5574                               bool GenerateHash, ModuleHash *ModHash) {
5575   auto Write = [&](BitcodeWriter &Writer) {
5576     Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
5577                        ModHash);
5578     Writer.writeSymtab();
5579     Writer.writeStrtab();
5580   };
5581   Triple TT(M.getTargetTriple());
5582   if (TT.isOSDarwin() || TT.isOSBinFormatMachO()) {
5583     // If this is darwin or another generic macho target, reserve space for the
5584     // header. Note that the header is computed *after* the output is known, so
5585     // we currently explicitly use a buffer, write to it, and then subsequently
5586     // flush to Out.
5587     SmallVector<char, 0> Buffer;
5588     Buffer.reserve(256 * 1024);
5589     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
5590     BitcodeWriter Writer(Buffer);
5591     Write(Writer);
5592     emitDarwinBCHeaderAndTrailer(Buffer, TT);
5593     Out.write(Buffer.data(), Buffer.size());
5594   } else {
5595     BitcodeWriter Writer(Out);
5596     Write(Writer);
5597   }
5598 }
5599 
5600 void IndexBitcodeWriter::write() {
5601   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5602 
5603   writeModuleVersion();
5604 
5605   // Write the module paths in the combined index.
5606   writeModStrings();
5607 
5608   // Write the summary combined index records.
5609   writeCombinedGlobalValueSummary();
5610 
5611   Stream.ExitBlock();
5612 }
5613 
5614 // Write the specified module summary index to the given raw output stream,
5615 // where it will be written in a new bitcode block. This is used when
5616 // writing the combined index file for ThinLTO. When writing a subset of the
5617 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
5618 void llvm::writeIndexToFile(
5619     const ModuleSummaryIndex &Index, raw_ostream &Out,
5620     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5621     const GVSummaryPtrSet *DecSummaries) {
5622   SmallVector<char, 0> Buffer;
5623   Buffer.reserve(256 * 1024);
5624 
5625   BitcodeWriter Writer(Buffer);
5626   Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
5627   Writer.writeStrtab();
5628 
5629   Out.write((char *)&Buffer.front(), Buffer.size());
5630 }
5631 
5632 namespace {
5633 
5634 /// Class to manage the bitcode writing for a thin link bitcode file.
5635 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
5636   /// ModHash is for use in ThinLTO incremental build, generated while writing
5637   /// the module bitcode file.
5638   const ModuleHash *ModHash;
5639 
5640 public:
5641   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
5642                         BitstreamWriter &Stream,
5643                         const ModuleSummaryIndex &Index,
5644                         const ModuleHash &ModHash)
5645       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
5646                                 /*ShouldPreserveUseListOrder=*/false, &Index),
5647         ModHash(&ModHash) {}
5648 
5649   void write();
5650 
5651 private:
5652   void writeSimplifiedModuleInfo();
5653 };
5654 
5655 } // end anonymous namespace
5656 
5657 // This function writes a simpilified module info for thin link bitcode file.
5658 // It only contains the source file name along with the name(the offset and
5659 // size in strtab) and linkage for global values. For the global value info
5660 // entry, in order to keep linkage at offset 5, there are three zeros used
5661 // as padding.
5662 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
5663   SmallVector<unsigned, 64> Vals;
5664   // Emit the module's source file name.
5665   {
5666     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
5667     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
5668     if (Bits == SE_Char6)
5669       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
5670     else if (Bits == SE_Fixed7)
5671       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5672 
5673     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5674     auto Abbv = std::make_shared<BitCodeAbbrev>();
5675     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5677     Abbv->Add(AbbrevOpToUse);
5678     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5679 
5680     for (const auto P : M.getSourceFileName())
5681       Vals.push_back((unsigned char)P);
5682 
5683     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5684     Vals.clear();
5685   }
5686 
5687   // Emit the global variable information.
5688   for (const GlobalVariable &GV : M.globals()) {
5689     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5690     Vals.push_back(StrtabBuilder.add(GV.getName()));
5691     Vals.push_back(GV.getName().size());
5692     Vals.push_back(0);
5693     Vals.push_back(0);
5694     Vals.push_back(0);
5695     Vals.push_back(getEncodedLinkage(GV));
5696 
5697     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5698     Vals.clear();
5699   }
5700 
5701   // Emit the function proto information.
5702   for (const Function &F : M) {
5703     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5704     Vals.push_back(StrtabBuilder.add(F.getName()));
5705     Vals.push_back(F.getName().size());
5706     Vals.push_back(0);
5707     Vals.push_back(0);
5708     Vals.push_back(0);
5709     Vals.push_back(getEncodedLinkage(F));
5710 
5711     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5712     Vals.clear();
5713   }
5714 
5715   // Emit the alias information.
5716   for (const GlobalAlias &A : M.aliases()) {
5717     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5718     Vals.push_back(StrtabBuilder.add(A.getName()));
5719     Vals.push_back(A.getName().size());
5720     Vals.push_back(0);
5721     Vals.push_back(0);
5722     Vals.push_back(0);
5723     Vals.push_back(getEncodedLinkage(A));
5724 
5725     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5726     Vals.clear();
5727   }
5728 
5729   // Emit the ifunc information.
5730   for (const GlobalIFunc &I : M.ifuncs()) {
5731     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5732     Vals.push_back(StrtabBuilder.add(I.getName()));
5733     Vals.push_back(I.getName().size());
5734     Vals.push_back(0);
5735     Vals.push_back(0);
5736     Vals.push_back(0);
5737     Vals.push_back(getEncodedLinkage(I));
5738 
5739     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5740     Vals.clear();
5741   }
5742 }
5743 
5744 void ThinLinkBitcodeWriter::write() {
5745   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5746 
5747   writeModuleVersion();
5748 
5749   writeSimplifiedModuleInfo();
5750 
5751   writePerModuleGlobalValueSummary();
5752 
5753   // Write module hash.
5754   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5755 
5756   Stream.ExitBlock();
5757 }
5758 
5759 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5760                                          const ModuleSummaryIndex &Index,
5761                                          const ModuleHash &ModHash) {
5762   assert(!WroteStrtab);
5763 
5764   // The Mods vector is used by irsymtab::build, which requires non-const
5765   // Modules in case it needs to materialize metadata. But the bitcode writer
5766   // requires that the module is materialized, so we can cast to non-const here,
5767   // after checking that it is in fact materialized.
5768   assert(M.isMaterialized());
5769   Mods.push_back(const_cast<Module *>(&M));
5770 
5771   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5772                                        ModHash);
5773   ThinLinkWriter.write();
5774 }
5775 
5776 // Write the specified thin link bitcode file to the given raw output stream,
5777 // where it will be written in a new bitcode block. This is used when
5778 // writing the per-module index file for ThinLTO.
5779 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5780                                       const ModuleSummaryIndex &Index,
5781                                       const ModuleHash &ModHash) {
5782   SmallVector<char, 0> Buffer;
5783   Buffer.reserve(256 * 1024);
5784 
5785   BitcodeWriter Writer(Buffer);
5786   Writer.writeThinLinkBitcode(M, Index, ModHash);
5787   Writer.writeSymtab();
5788   Writer.writeStrtab();
5789 
5790   Out.write((char *)&Buffer.front(), Buffer.size());
5791 }
5792 
5793 static const char *getSectionNameForBitcode(const Triple &T) {
5794   switch (T.getObjectFormat()) {
5795   case Triple::MachO:
5796     return "__LLVM,__bitcode";
5797   case Triple::COFF:
5798   case Triple::ELF:
5799   case Triple::Wasm:
5800   case Triple::UnknownObjectFormat:
5801     return ".llvmbc";
5802   case Triple::GOFF:
5803     llvm_unreachable("GOFF is not yet implemented");
5804     break;
5805   case Triple::SPIRV:
5806     if (T.getVendor() == Triple::AMD)
5807       return ".llvmbc";
5808     llvm_unreachable("SPIRV is not yet implemented");
5809     break;
5810   case Triple::XCOFF:
5811     llvm_unreachable("XCOFF is not yet implemented");
5812     break;
5813   case Triple::DXContainer:
5814     llvm_unreachable("DXContainer is not yet implemented");
5815     break;
5816   }
5817   llvm_unreachable("Unimplemented ObjectFormatType");
5818 }
5819 
5820 static const char *getSectionNameForCommandline(const Triple &T) {
5821   switch (T.getObjectFormat()) {
5822   case Triple::MachO:
5823     return "__LLVM,__cmdline";
5824   case Triple::COFF:
5825   case Triple::ELF:
5826   case Triple::Wasm:
5827   case Triple::UnknownObjectFormat:
5828     return ".llvmcmd";
5829   case Triple::GOFF:
5830     llvm_unreachable("GOFF is not yet implemented");
5831     break;
5832   case Triple::SPIRV:
5833     if (T.getVendor() == Triple::AMD)
5834       return ".llvmcmd";
5835     llvm_unreachable("SPIRV is not yet implemented");
5836     break;
5837   case Triple::XCOFF:
5838     llvm_unreachable("XCOFF is not yet implemented");
5839     break;
5840   case Triple::DXContainer:
5841     llvm_unreachable("DXC is not yet implemented");
5842     break;
5843   }
5844   llvm_unreachable("Unimplemented ObjectFormatType");
5845 }
5846 
5847 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5848                                 bool EmbedBitcode, bool EmbedCmdline,
5849                                 const std::vector<uint8_t> &CmdArgs) {
5850   // Save llvm.compiler.used and remove it.
5851   SmallVector<Constant *, 2> UsedArray;
5852   SmallVector<GlobalValue *, 4> UsedGlobals;
5853   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5854   Type *UsedElementType = Used ? Used->getValueType()->getArrayElementType()
5855                                : PointerType::getUnqual(M.getContext());
5856   for (auto *GV : UsedGlobals) {
5857     if (GV->getName() != "llvm.embedded.module" &&
5858         GV->getName() != "llvm.cmdline")
5859       UsedArray.push_back(
5860           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5861   }
5862   if (Used)
5863     Used->eraseFromParent();
5864 
5865   // Embed the bitcode for the llvm module.
5866   std::string Data;
5867   ArrayRef<uint8_t> ModuleData;
5868   Triple T(M.getTargetTriple());
5869 
5870   if (EmbedBitcode) {
5871     if (Buf.getBufferSize() == 0 ||
5872         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5873                    (const unsigned char *)Buf.getBufferEnd())) {
5874       // If the input is LLVM Assembly, bitcode is produced by serializing
5875       // the module. Use-lists order need to be preserved in this case.
5876       llvm::raw_string_ostream OS(Data);
5877       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5878       ModuleData =
5879           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5880     } else
5881       // If the input is LLVM bitcode, write the input byte stream directly.
5882       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5883                                      Buf.getBufferSize());
5884   }
5885   llvm::Constant *ModuleConstant =
5886       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5887   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5888       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5889       ModuleConstant);
5890   GV->setSection(getSectionNameForBitcode(T));
5891   // Set alignment to 1 to prevent padding between two contributions from input
5892   // sections after linking.
5893   GV->setAlignment(Align(1));
5894   UsedArray.push_back(
5895       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5896   if (llvm::GlobalVariable *Old =
5897           M.getGlobalVariable("llvm.embedded.module", true)) {
5898     assert(Old->hasZeroLiveUses() &&
5899            "llvm.embedded.module can only be used once in llvm.compiler.used");
5900     GV->takeName(Old);
5901     Old->eraseFromParent();
5902   } else {
5903     GV->setName("llvm.embedded.module");
5904   }
5905 
5906   // Skip if only bitcode needs to be embedded.
5907   if (EmbedCmdline) {
5908     // Embed command-line options.
5909     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5910                               CmdArgs.size());
5911     llvm::Constant *CmdConstant =
5912         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5913     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5914                                   llvm::GlobalValue::PrivateLinkage,
5915                                   CmdConstant);
5916     GV->setSection(getSectionNameForCommandline(T));
5917     GV->setAlignment(Align(1));
5918     UsedArray.push_back(
5919         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5920     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5921       assert(Old->hasZeroLiveUses() &&
5922              "llvm.cmdline can only be used once in llvm.compiler.used");
5923       GV->takeName(Old);
5924       Old->eraseFromParent();
5925     } else {
5926       GV->setName("llvm.cmdline");
5927     }
5928   }
5929 
5930   if (UsedArray.empty())
5931     return;
5932 
5933   // Recreate llvm.compiler.used.
5934   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5935   auto *NewUsed = new GlobalVariable(
5936       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5937       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5938   NewUsed->setSection("llvm.metadata");
5939 }
5940