xref: /freebsd/contrib/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp (revision ec0ea6efa1ad229d75c394c1a9b9cac33af2b1d3)
1 //===- DWARFDebugLine.cpp -------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
10 #include "llvm/ADT/Optional.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/BinaryFormat/Dwarf.h"
15 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
16 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
17 #include "llvm/Support/Errc.h"
18 #include "llvm/Support/Format.h"
19 #include "llvm/Support/FormatVariadic.h"
20 #include "llvm/Support/WithColor.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <algorithm>
23 #include <cassert>
24 #include <cinttypes>
25 #include <cstdint>
26 #include <cstdio>
27 #include <utility>
28 
29 using namespace llvm;
30 using namespace dwarf;
31 
32 using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;
33 
34 namespace {
35 
36 struct ContentDescriptor {
37   dwarf::LineNumberEntryFormat Type;
38   dwarf::Form Form;
39 };
40 
41 using ContentDescriptors = SmallVector<ContentDescriptor, 4>;
42 
43 } // end anonymous namespace
44 
45 static bool versionIsSupported(uint16_t Version) {
46   return Version >= 2 && Version <= 5;
47 }
48 
49 void DWARFDebugLine::ContentTypeTracker::trackContentType(
50     dwarf::LineNumberEntryFormat ContentType) {
51   switch (ContentType) {
52   case dwarf::DW_LNCT_timestamp:
53     HasModTime = true;
54     break;
55   case dwarf::DW_LNCT_size:
56     HasLength = true;
57     break;
58   case dwarf::DW_LNCT_MD5:
59     HasMD5 = true;
60     break;
61   case dwarf::DW_LNCT_LLVM_source:
62     HasSource = true;
63     break;
64   default:
65     // We only care about values we consider optional, and new values may be
66     // added in the vendor extension range, so we do not match exhaustively.
67     break;
68   }
69 }
70 
71 DWARFDebugLine::Prologue::Prologue() { clear(); }
72 
73 bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
74   uint16_t DwarfVersion = getVersion();
75   assert(DwarfVersion != 0 &&
76          "line table prologue has no dwarf version information");
77   if (DwarfVersion >= 5)
78     return FileIndex < FileNames.size();
79   return FileIndex != 0 && FileIndex <= FileNames.size();
80 }
81 
82 Optional<uint64_t> DWARFDebugLine::Prologue::getLastValidFileIndex() const {
83   if (FileNames.empty())
84     return None;
85   uint16_t DwarfVersion = getVersion();
86   assert(DwarfVersion != 0 &&
87          "line table prologue has no dwarf version information");
88   // In DWARF v5 the file names are 0-indexed.
89   if (DwarfVersion >= 5)
90     return FileNames.size() - 1;
91   return FileNames.size();
92 }
93 
94 const llvm::DWARFDebugLine::FileNameEntry &
95 DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
96   uint16_t DwarfVersion = getVersion();
97   assert(DwarfVersion != 0 &&
98          "line table prologue has no dwarf version information");
99   // In DWARF v5 the file names are 0-indexed.
100   if (DwarfVersion >= 5)
101     return FileNames[Index];
102   return FileNames[Index - 1];
103 }
104 
105 void DWARFDebugLine::Prologue::clear() {
106   TotalLength = PrologueLength = 0;
107   SegSelectorSize = 0;
108   MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
109   OpcodeBase = 0;
110   FormParams = dwarf::FormParams({0, 0, DWARF32});
111   ContentTypes = ContentTypeTracker();
112   StandardOpcodeLengths.clear();
113   IncludeDirectories.clear();
114   FileNames.clear();
115 }
116 
117 void DWARFDebugLine::Prologue::dump(raw_ostream &OS,
118                                     DIDumpOptions DumpOptions) const {
119   if (!totalLengthIsValid())
120     return;
121   int OffsetDumpWidth = 2 * dwarf::getDwarfOffsetByteSize(FormParams.Format);
122   OS << "Line table prologue:\n"
123      << format("    total_length: 0x%0*" PRIx64 "\n", OffsetDumpWidth,
124                TotalLength)
125      << "          format: " << dwarf::FormatString(FormParams.Format) << "\n"
126      << format("         version: %u\n", getVersion());
127   if (!versionIsSupported(getVersion()))
128     return;
129   if (getVersion() >= 5)
130     OS << format("    address_size: %u\n", getAddressSize())
131        << format(" seg_select_size: %u\n", SegSelectorSize);
132   OS << format(" prologue_length: 0x%0*" PRIx64 "\n", OffsetDumpWidth,
133                PrologueLength)
134      << format(" min_inst_length: %u\n", MinInstLength)
135      << format(getVersion() >= 4 ? "max_ops_per_inst: %u\n" : "", MaxOpsPerInst)
136      << format(" default_is_stmt: %u\n", DefaultIsStmt)
137      << format("       line_base: %i\n", LineBase)
138      << format("      line_range: %u\n", LineRange)
139      << format("     opcode_base: %u\n", OpcodeBase);
140 
141   for (uint32_t I = 0; I != StandardOpcodeLengths.size(); ++I)
142     OS << formatv("standard_opcode_lengths[{0}] = {1}\n",
143                   static_cast<dwarf::LineNumberOps>(I + 1),
144                   StandardOpcodeLengths[I]);
145 
146   if (!IncludeDirectories.empty()) {
147     // DWARF v5 starts directory indexes at 0.
148     uint32_t DirBase = getVersion() >= 5 ? 0 : 1;
149     for (uint32_t I = 0; I != IncludeDirectories.size(); ++I) {
150       OS << format("include_directories[%3u] = ", I + DirBase);
151       IncludeDirectories[I].dump(OS, DumpOptions);
152       OS << '\n';
153     }
154   }
155 
156   if (!FileNames.empty()) {
157     // DWARF v5 starts file indexes at 0.
158     uint32_t FileBase = getVersion() >= 5 ? 0 : 1;
159     for (uint32_t I = 0; I != FileNames.size(); ++I) {
160       const FileNameEntry &FileEntry = FileNames[I];
161       OS <<   format("file_names[%3u]:\n", I + FileBase);
162       OS <<          "           name: ";
163       FileEntry.Name.dump(OS, DumpOptions);
164       OS << '\n'
165          <<   format("      dir_index: %" PRIu64 "\n", FileEntry.DirIdx);
166       if (ContentTypes.HasMD5)
167         OS <<        "   md5_checksum: " << FileEntry.Checksum.digest() << '\n';
168       if (ContentTypes.HasModTime)
169         OS << format("       mod_time: 0x%8.8" PRIx64 "\n", FileEntry.ModTime);
170       if (ContentTypes.HasLength)
171         OS << format("         length: 0x%8.8" PRIx64 "\n", FileEntry.Length);
172       if (ContentTypes.HasSource) {
173         OS <<        "         source: ";
174         FileEntry.Source.dump(OS, DumpOptions);
175         OS << '\n';
176       }
177     }
178   }
179 }
180 
181 // Parse v2-v4 directory and file tables.
182 static Error
183 parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
184                      uint64_t *OffsetPtr,
185                      DWARFDebugLine::ContentTypeTracker &ContentTypes,
186                      std::vector<DWARFFormValue> &IncludeDirectories,
187                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
188   while (true) {
189     Error Err = Error::success();
190     StringRef S = DebugLineData.getCStrRef(OffsetPtr, &Err);
191     if (Err) {
192       consumeError(std::move(Err));
193       return createStringError(errc::invalid_argument,
194                                "include directories table was not null "
195                                "terminated before the end of the prologue");
196     }
197     if (S.empty())
198       break;
199     DWARFFormValue Dir =
200         DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, S.data());
201     IncludeDirectories.push_back(Dir);
202   }
203 
204   ContentTypes.HasModTime = true;
205   ContentTypes.HasLength = true;
206 
207   while (true) {
208     Error Err = Error::success();
209     StringRef Name = DebugLineData.getCStrRef(OffsetPtr, &Err);
210     if (!Err && Name.empty())
211       break;
212 
213     DWARFDebugLine::FileNameEntry FileEntry;
214     FileEntry.Name =
215         DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name.data());
216     FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr, &Err);
217     FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr, &Err);
218     FileEntry.Length = DebugLineData.getULEB128(OffsetPtr, &Err);
219 
220     if (Err) {
221       consumeError(std::move(Err));
222       return createStringError(
223           errc::invalid_argument,
224           "file names table was not null terminated before "
225           "the end of the prologue");
226     }
227     FileNames.push_back(FileEntry);
228   }
229 
230   return Error::success();
231 }
232 
233 // Parse v5 directory/file entry content descriptions.
234 // Returns the descriptors, or an error if we did not find a path or ran off
235 // the end of the prologue.
236 static llvm::Expected<ContentDescriptors>
237 parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
238                    DWARFDebugLine::ContentTypeTracker *ContentTypes) {
239   Error Err = Error::success();
240   ContentDescriptors Descriptors;
241   int FormatCount = DebugLineData.getU8(OffsetPtr, &Err);
242   bool HasPath = false;
243   for (int I = 0; I != FormatCount && !Err; ++I) {
244     ContentDescriptor Descriptor;
245     Descriptor.Type =
246         dwarf::LineNumberEntryFormat(DebugLineData.getULEB128(OffsetPtr, &Err));
247     Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr, &Err));
248     if (Descriptor.Type == dwarf::DW_LNCT_path)
249       HasPath = true;
250     if (ContentTypes)
251       ContentTypes->trackContentType(Descriptor.Type);
252     Descriptors.push_back(Descriptor);
253   }
254 
255   if (Err)
256     return createStringError(errc::invalid_argument,
257                              "failed to parse entry content descriptors: %s",
258                              toString(std::move(Err)).c_str());
259 
260   if (!HasPath)
261     return createStringError(errc::invalid_argument,
262                              "failed to parse entry content descriptions"
263                              " because no path was found");
264   return Descriptors;
265 }
266 
267 static Error
268 parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
269                      uint64_t *OffsetPtr, const dwarf::FormParams &FormParams,
270                      const DWARFContext &Ctx, const DWARFUnit *U,
271                      DWARFDebugLine::ContentTypeTracker &ContentTypes,
272                      std::vector<DWARFFormValue> &IncludeDirectories,
273                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
274   // Get the directory entry description.
275   llvm::Expected<ContentDescriptors> DirDescriptors =
276       parseV5EntryFormat(DebugLineData, OffsetPtr, nullptr);
277   if (!DirDescriptors)
278     return DirDescriptors.takeError();
279 
280   // Get the directory entries, according to the format described above.
281   uint64_t DirEntryCount = DebugLineData.getULEB128(OffsetPtr);
282   for (uint64_t I = 0; I != DirEntryCount; ++I) {
283     for (auto Descriptor : *DirDescriptors) {
284       DWARFFormValue Value(Descriptor.Form);
285       switch (Descriptor.Type) {
286       case DW_LNCT_path:
287         if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
288           return createStringError(errc::invalid_argument,
289                                    "failed to parse directory entry because "
290                                    "extracting the form value failed");
291         IncludeDirectories.push_back(Value);
292         break;
293       default:
294         if (!Value.skipValue(DebugLineData, OffsetPtr, FormParams))
295           return createStringError(errc::invalid_argument,
296                                    "failed to parse directory entry because "
297                                    "skipping the form value failed");
298       }
299     }
300   }
301 
302   // Get the file entry description.
303   llvm::Expected<ContentDescriptors> FileDescriptors =
304       parseV5EntryFormat(DebugLineData, OffsetPtr, &ContentTypes);
305   if (!FileDescriptors)
306     return FileDescriptors.takeError();
307 
308   // Get the file entries, according to the format described above.
309   uint64_t FileEntryCount = DebugLineData.getULEB128(OffsetPtr);
310   for (uint64_t I = 0; I != FileEntryCount; ++I) {
311     DWARFDebugLine::FileNameEntry FileEntry;
312     for (auto Descriptor : *FileDescriptors) {
313       DWARFFormValue Value(Descriptor.Form);
314       if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
315         return createStringError(errc::invalid_argument,
316                                  "failed to parse file entry because "
317                                  "extracting the form value failed");
318       switch (Descriptor.Type) {
319       case DW_LNCT_path:
320         FileEntry.Name = Value;
321         break;
322       case DW_LNCT_LLVM_source:
323         FileEntry.Source = Value;
324         break;
325       case DW_LNCT_directory_index:
326         FileEntry.DirIdx = Value.getAsUnsignedConstant().getValue();
327         break;
328       case DW_LNCT_timestamp:
329         FileEntry.ModTime = Value.getAsUnsignedConstant().getValue();
330         break;
331       case DW_LNCT_size:
332         FileEntry.Length = Value.getAsUnsignedConstant().getValue();
333         break;
334       case DW_LNCT_MD5:
335         if (!Value.getAsBlock() || Value.getAsBlock().getValue().size() != 16)
336           return createStringError(
337               errc::invalid_argument,
338               "failed to parse file entry because the MD5 hash is invalid");
339         std::uninitialized_copy_n(Value.getAsBlock().getValue().begin(), 16,
340                                   FileEntry.Checksum.Bytes.begin());
341         break;
342       default:
343         break;
344       }
345     }
346     FileNames.push_back(FileEntry);
347   }
348   return Error::success();
349 }
350 
351 uint64_t DWARFDebugLine::Prologue::getLength() const {
352   uint64_t Length = PrologueLength + sizeofTotalLength() +
353                     sizeof(getVersion()) + sizeofPrologueLength();
354   if (getVersion() >= 5)
355     Length += 2; // Address + Segment selector sizes.
356   return Length;
357 }
358 
359 Error DWARFDebugLine::Prologue::parse(
360     DWARFDataExtractor DebugLineData, uint64_t *OffsetPtr,
361     function_ref<void(Error)> RecoverableErrorHandler, const DWARFContext &Ctx,
362     const DWARFUnit *U) {
363   const uint64_t PrologueOffset = *OffsetPtr;
364 
365   clear();
366   DataExtractor::Cursor Cursor(*OffsetPtr);
367   std::tie(TotalLength, FormParams.Format) =
368       DebugLineData.getInitialLength(Cursor);
369 
370   DebugLineData =
371       DWARFDataExtractor(DebugLineData, Cursor.tell() + TotalLength);
372   FormParams.Version = DebugLineData.getU16(Cursor);
373   if (Cursor && !versionIsSupported(getVersion())) {
374     // Treat this error as unrecoverable - we cannot be sure what any of
375     // the data represents including the length field, so cannot skip it or make
376     // any reasonable assumptions.
377     *OffsetPtr = Cursor.tell();
378     return createStringError(
379         errc::not_supported,
380         "parsing line table prologue at offset 0x%8.8" PRIx64
381         ": unsupported version %" PRIu16,
382         PrologueOffset, getVersion());
383   }
384 
385   if (getVersion() >= 5) {
386     FormParams.AddrSize = DebugLineData.getU8(Cursor);
387     assert((!Cursor || DebugLineData.getAddressSize() == 0 ||
388             DebugLineData.getAddressSize() == getAddressSize()) &&
389            "Line table header and data extractor disagree");
390     SegSelectorSize = DebugLineData.getU8(Cursor);
391   }
392 
393   PrologueLength =
394       DebugLineData.getRelocatedValue(Cursor, sizeofPrologueLength());
395   const uint64_t EndPrologueOffset = PrologueLength + Cursor.tell();
396   DebugLineData = DWARFDataExtractor(DebugLineData, EndPrologueOffset);
397   MinInstLength = DebugLineData.getU8(Cursor);
398   if (getVersion() >= 4)
399     MaxOpsPerInst = DebugLineData.getU8(Cursor);
400   DefaultIsStmt = DebugLineData.getU8(Cursor);
401   LineBase = DebugLineData.getU8(Cursor);
402   LineRange = DebugLineData.getU8(Cursor);
403   OpcodeBase = DebugLineData.getU8(Cursor);
404 
405   if (Cursor && OpcodeBase == 0) {
406     // If the opcode base is 0, we cannot read the standard opcode lengths (of
407     // which there are supposed to be one fewer than the opcode base). Assume
408     // there are no standard opcodes and continue parsing.
409     RecoverableErrorHandler(createStringError(
410         errc::invalid_argument,
411         "parsing line table prologue at offset 0x%8.8" PRIx64
412         " found opcode base of 0. Assuming no standard opcodes",
413         PrologueOffset));
414   } else if (Cursor) {
415     StandardOpcodeLengths.reserve(OpcodeBase - 1);
416     for (uint32_t I = 1; I < OpcodeBase; ++I) {
417       uint8_t OpLen = DebugLineData.getU8(Cursor);
418       StandardOpcodeLengths.push_back(OpLen);
419     }
420   }
421 
422   *OffsetPtr = Cursor.tell();
423   // A corrupt file name or directory table does not prevent interpretation of
424   // the main line program, so check the cursor state now so that its errors can
425   // be handled separately.
426   if (!Cursor)
427     return createStringError(
428         errc::invalid_argument,
429         "parsing line table prologue at offset 0x%8.8" PRIx64 ": %s",
430         PrologueOffset, toString(Cursor.takeError()).c_str());
431 
432   Error E =
433       getVersion() >= 5
434           ? parseV5DirFileTables(DebugLineData, OffsetPtr, FormParams, Ctx, U,
435                                  ContentTypes, IncludeDirectories, FileNames)
436           : parseV2DirFileTables(DebugLineData, OffsetPtr, ContentTypes,
437                                  IncludeDirectories, FileNames);
438   if (E) {
439     RecoverableErrorHandler(joinErrors(
440         createStringError(
441             errc::invalid_argument,
442             "parsing line table prologue at 0x%8.8" PRIx64
443             " found an invalid directory or file table description at"
444             " 0x%8.8" PRIx64,
445             PrologueOffset, *OffsetPtr),
446         std::move(E)));
447     return Error::success();
448   }
449 
450   assert(*OffsetPtr <= EndPrologueOffset);
451   if (*OffsetPtr != EndPrologueOffset) {
452     RecoverableErrorHandler(createStringError(
453         errc::invalid_argument,
454         "unknown data in line table prologue at offset 0x%8.8" PRIx64
455         ": parsing ended (at offset 0x%8.8" PRIx64
456         ") before reaching the prologue end at offset 0x%8.8" PRIx64,
457         PrologueOffset, *OffsetPtr, EndPrologueOffset));
458   }
459   return Error::success();
460 }
461 
462 DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }
463 
464 void DWARFDebugLine::Row::postAppend() {
465   Discriminator = 0;
466   BasicBlock = false;
467   PrologueEnd = false;
468   EpilogueBegin = false;
469 }
470 
471 void DWARFDebugLine::Row::reset(bool DefaultIsStmt) {
472   Address.Address = 0;
473   Address.SectionIndex = object::SectionedAddress::UndefSection;
474   Line = 1;
475   Column = 0;
476   File = 1;
477   Isa = 0;
478   Discriminator = 0;
479   IsStmt = DefaultIsStmt;
480   BasicBlock = false;
481   EndSequence = false;
482   PrologueEnd = false;
483   EpilogueBegin = false;
484 }
485 
486 void DWARFDebugLine::Row::dumpTableHeader(raw_ostream &OS, unsigned Indent) {
487   OS.indent(Indent)
488       << "Address            Line   Column File   ISA Discriminator Flags\n";
489   OS.indent(Indent)
490       << "------------------ ------ ------ ------ --- ------------- "
491          "-------------\n";
492 }
493 
494 void DWARFDebugLine::Row::dump(raw_ostream &OS) const {
495   OS << format("0x%16.16" PRIx64 " %6u %6u", Address.Address, Line, Column)
496      << format(" %6u %3u %13u ", File, Isa, Discriminator)
497      << (IsStmt ? " is_stmt" : "") << (BasicBlock ? " basic_block" : "")
498      << (PrologueEnd ? " prologue_end" : "")
499      << (EpilogueBegin ? " epilogue_begin" : "")
500      << (EndSequence ? " end_sequence" : "") << '\n';
501 }
502 
503 DWARFDebugLine::Sequence::Sequence() { reset(); }
504 
505 void DWARFDebugLine::Sequence::reset() {
506   LowPC = 0;
507   HighPC = 0;
508   SectionIndex = object::SectionedAddress::UndefSection;
509   FirstRowIndex = 0;
510   LastRowIndex = 0;
511   Empty = true;
512 }
513 
514 DWARFDebugLine::LineTable::LineTable() { clear(); }
515 
516 void DWARFDebugLine::LineTable::dump(raw_ostream &OS,
517                                      DIDumpOptions DumpOptions) const {
518   Prologue.dump(OS, DumpOptions);
519 
520   if (!Rows.empty()) {
521     OS << '\n';
522     Row::dumpTableHeader(OS, 0);
523     for (const Row &R : Rows) {
524       R.dump(OS);
525     }
526   }
527 
528   // Terminate the table with a final blank line to clearly delineate it from
529   // later dumps.
530   OS << '\n';
531 }
532 
533 void DWARFDebugLine::LineTable::clear() {
534   Prologue.clear();
535   Rows.clear();
536   Sequences.clear();
537 }
538 
539 DWARFDebugLine::ParsingState::ParsingState(
540     struct LineTable *LT, uint64_t TableOffset,
541     function_ref<void(Error)> ErrorHandler)
542     : LineTable(LT), LineTableOffset(TableOffset), ErrorHandler(ErrorHandler) {
543   resetRowAndSequence();
544 }
545 
546 void DWARFDebugLine::ParsingState::resetRowAndSequence() {
547   Row.reset(LineTable->Prologue.DefaultIsStmt);
548   Sequence.reset();
549 }
550 
551 void DWARFDebugLine::ParsingState::appendRowToMatrix() {
552   unsigned RowNumber = LineTable->Rows.size();
553   if (Sequence.Empty) {
554     // Record the beginning of instruction sequence.
555     Sequence.Empty = false;
556     Sequence.LowPC = Row.Address.Address;
557     Sequence.FirstRowIndex = RowNumber;
558   }
559   LineTable->appendRow(Row);
560   if (Row.EndSequence) {
561     // Record the end of instruction sequence.
562     Sequence.HighPC = Row.Address.Address;
563     Sequence.LastRowIndex = RowNumber + 1;
564     Sequence.SectionIndex = Row.Address.SectionIndex;
565     if (Sequence.isValid())
566       LineTable->appendSequence(Sequence);
567     Sequence.reset();
568   }
569   Row.postAppend();
570 }
571 
572 const DWARFDebugLine::LineTable *
573 DWARFDebugLine::getLineTable(uint64_t Offset) const {
574   LineTableConstIter Pos = LineTableMap.find(Offset);
575   if (Pos != LineTableMap.end())
576     return &Pos->second;
577   return nullptr;
578 }
579 
580 Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
581     DWARFDataExtractor &DebugLineData, uint64_t Offset, const DWARFContext &Ctx,
582     const DWARFUnit *U, function_ref<void(Error)> RecoverableErrorHandler) {
583   if (!DebugLineData.isValidOffset(Offset))
584     return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx64
585                        " is not a valid debug line section offset",
586                        Offset);
587 
588   std::pair<LineTableIter, bool> Pos =
589       LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
590   LineTable *LT = &Pos.first->second;
591   if (Pos.second) {
592     if (Error Err =
593             LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorHandler))
594       return std::move(Err);
595     return LT;
596   }
597   return LT;
598 }
599 
600 static StringRef getOpcodeName(uint8_t Opcode, uint8_t OpcodeBase) {
601   assert(Opcode != 0);
602   if (Opcode < OpcodeBase)
603     return LNStandardString(Opcode);
604   return "special";
605 }
606 
607 uint64_t DWARFDebugLine::ParsingState::advanceAddr(uint64_t OperationAdvance,
608                                                    uint8_t Opcode,
609                                                    uint64_t OpcodeOffset) {
610   StringRef OpcodeName = getOpcodeName(Opcode, LineTable->Prologue.OpcodeBase);
611   // For versions less than 4, the MaxOpsPerInst member is set to 0, as the
612   // maximum_operations_per_instruction field wasn't introduced until DWARFv4.
613   // Don't warn about bad values in this situation.
614   if (ReportAdvanceAddrProblem && LineTable->Prologue.getVersion() >= 4 &&
615       LineTable->Prologue.MaxOpsPerInst != 1)
616     ErrorHandler(createStringError(
617         errc::not_supported,
618         "line table program at offset 0x%8.8" PRIx64
619         " contains a %s opcode at offset 0x%8.8" PRIx64
620         ", but the prologue maximum_operations_per_instruction value is %" PRId8
621         ", which is unsupported. Assuming a value of 1 instead",
622         LineTableOffset, OpcodeName.data(), OpcodeOffset,
623         LineTable->Prologue.MaxOpsPerInst));
624   if (ReportAdvanceAddrProblem && LineTable->Prologue.MinInstLength == 0)
625     ErrorHandler(
626         createStringError(errc::invalid_argument,
627                           "line table program at offset 0x%8.8" PRIx64
628                           " contains a %s opcode at offset 0x%8.8" PRIx64
629                           ", but the prologue minimum_instruction_length value "
630                           "is 0, which prevents any address advancing",
631                           LineTableOffset, OpcodeName.data(), OpcodeOffset));
632   ReportAdvanceAddrProblem = false;
633   uint64_t AddrOffset = OperationAdvance * LineTable->Prologue.MinInstLength;
634   Row.Address.Address += AddrOffset;
635   return AddrOffset;
636 }
637 
638 DWARFDebugLine::ParsingState::AddrAndAdjustedOpcode
639 DWARFDebugLine::ParsingState::advanceAddrForOpcode(uint8_t Opcode,
640                                                    uint64_t OpcodeOffset) {
641   assert(Opcode == DW_LNS_const_add_pc ||
642          Opcode >= LineTable->Prologue.OpcodeBase);
643   if (ReportBadLineRange && LineTable->Prologue.LineRange == 0) {
644     StringRef OpcodeName =
645         getOpcodeName(Opcode, LineTable->Prologue.OpcodeBase);
646     ErrorHandler(
647         createStringError(errc::not_supported,
648                           "line table program at offset 0x%8.8" PRIx64
649                           " contains a %s opcode at offset 0x%8.8" PRIx64
650                           ", but the prologue line_range value is 0. The "
651                           "address and line will not be adjusted",
652                           LineTableOffset, OpcodeName.data(), OpcodeOffset));
653     ReportBadLineRange = false;
654   }
655 
656   uint8_t OpcodeValue = Opcode;
657   if (Opcode == DW_LNS_const_add_pc)
658     OpcodeValue = 255;
659   uint8_t AdjustedOpcode = OpcodeValue - LineTable->Prologue.OpcodeBase;
660   uint64_t OperationAdvance =
661       LineTable->Prologue.LineRange != 0
662           ? AdjustedOpcode / LineTable->Prologue.LineRange
663           : 0;
664   uint64_t AddrOffset = advanceAddr(OperationAdvance, Opcode, OpcodeOffset);
665   return {AddrOffset, AdjustedOpcode};
666 }
667 
668 DWARFDebugLine::ParsingState::AddrAndLineDelta
669 DWARFDebugLine::ParsingState::handleSpecialOpcode(uint8_t Opcode,
670                                                   uint64_t OpcodeOffset) {
671   // A special opcode value is chosen based on the amount that needs
672   // to be added to the line and address registers. The maximum line
673   // increment for a special opcode is the value of the line_base
674   // field in the header, plus the value of the line_range field,
675   // minus 1 (line base + line range - 1). If the desired line
676   // increment is greater than the maximum line increment, a standard
677   // opcode must be used instead of a special opcode. The "address
678   // advance" is calculated by dividing the desired address increment
679   // by the minimum_instruction_length field from the header. The
680   // special opcode is then calculated using the following formula:
681   //
682   //  opcode = (desired line increment - line_base) +
683   //           (line_range * address advance) + opcode_base
684   //
685   // If the resulting opcode is greater than 255, a standard opcode
686   // must be used instead.
687   //
688   // To decode a special opcode, subtract the opcode_base from the
689   // opcode itself to give the adjusted opcode. The amount to
690   // increment the address register is the result of the adjusted
691   // opcode divided by the line_range multiplied by the
692   // minimum_instruction_length field from the header. That is:
693   //
694   //  address increment = (adjusted opcode / line_range) *
695   //                      minimum_instruction_length
696   //
697   // The amount to increment the line register is the line_base plus
698   // the result of the adjusted opcode modulo the line_range. That is:
699   //
700   // line increment = line_base + (adjusted opcode % line_range)
701 
702   DWARFDebugLine::ParsingState::AddrAndAdjustedOpcode AddrAdvanceResult =
703       advanceAddrForOpcode(Opcode, OpcodeOffset);
704   int32_t LineOffset = 0;
705   if (LineTable->Prologue.LineRange != 0)
706     LineOffset =
707         LineTable->Prologue.LineBase +
708         (AddrAdvanceResult.AdjustedOpcode % LineTable->Prologue.LineRange);
709   Row.Line += LineOffset;
710   return {AddrAdvanceResult.AddrDelta, LineOffset};
711 }
712 
713 /// Parse a ULEB128 using the specified \p Cursor. \returns the parsed value on
714 /// success, or None if \p Cursor is in a failing state.
715 template <typename T>
716 static Optional<T> parseULEB128(DWARFDataExtractor &Data,
717                                 DataExtractor::Cursor &Cursor) {
718   T Value = Data.getULEB128(Cursor);
719   if (Cursor)
720     return Value;
721   return None;
722 }
723 
724 Error DWARFDebugLine::LineTable::parse(
725     DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
726     const DWARFContext &Ctx, const DWARFUnit *U,
727     function_ref<void(Error)> RecoverableErrorHandler, raw_ostream *OS,
728     bool Verbose) {
729   assert((OS || !Verbose) && "cannot have verbose output without stream");
730   const uint64_t DebugLineOffset = *OffsetPtr;
731 
732   clear();
733 
734   Error PrologueErr =
735       Prologue.parse(DebugLineData, OffsetPtr, RecoverableErrorHandler, Ctx, U);
736 
737   if (OS) {
738     DIDumpOptions DumpOptions;
739     DumpOptions.Verbose = Verbose;
740     Prologue.dump(*OS, DumpOptions);
741   }
742 
743   if (PrologueErr) {
744     // Ensure there is a blank line after the prologue to clearly delineate it
745     // from later dumps.
746     if (OS)
747       *OS << "\n";
748     return PrologueErr;
749   }
750 
751   uint64_t ProgramLength = Prologue.TotalLength + Prologue.sizeofTotalLength();
752   if (!DebugLineData.isValidOffsetForDataOfSize(DebugLineOffset,
753                                                 ProgramLength)) {
754     assert(DebugLineData.size() > DebugLineOffset &&
755            "prologue parsing should handle invalid offset");
756     uint64_t BytesRemaining = DebugLineData.size() - DebugLineOffset;
757     RecoverableErrorHandler(
758         createStringError(errc::invalid_argument,
759                           "line table program with offset 0x%8.8" PRIx64
760                           " has length 0x%8.8" PRIx64 " but only 0x%8.8" PRIx64
761                           " bytes are available",
762                           DebugLineOffset, ProgramLength, BytesRemaining));
763     // Continue by capping the length at the number of remaining bytes.
764     ProgramLength = BytesRemaining;
765   }
766 
767   // Create a DataExtractor which can only see the data up to the end of the
768   // table, to prevent reading past the end.
769   const uint64_t EndOffset = DebugLineOffset + ProgramLength;
770   DWARFDataExtractor TableData(DebugLineData, EndOffset);
771 
772   // See if we should tell the data extractor the address size.
773   if (TableData.getAddressSize() == 0)
774     TableData.setAddressSize(Prologue.getAddressSize());
775   else
776     assert(Prologue.getAddressSize() == 0 ||
777            Prologue.getAddressSize() == TableData.getAddressSize());
778 
779   ParsingState State(this, DebugLineOffset, RecoverableErrorHandler);
780 
781   *OffsetPtr = DebugLineOffset + Prologue.getLength();
782   if (OS && *OffsetPtr < EndOffset) {
783     *OS << '\n';
784     Row::dumpTableHeader(*OS, /*Indent=*/Verbose ? 12 : 0);
785   }
786   bool TombstonedAddress = false;
787   auto EmitRow = [&] {
788     if (!TombstonedAddress) {
789       if (Verbose) {
790         *OS << "\n";
791         OS->indent(12);
792       }
793       if (OS)
794         State.Row.dump(*OS);
795       State.appendRowToMatrix();
796     }
797   };
798   while (*OffsetPtr < EndOffset) {
799     DataExtractor::Cursor Cursor(*OffsetPtr);
800 
801     if (Verbose)
802       *OS << format("0x%08.08" PRIx64 ": ", *OffsetPtr);
803 
804     uint64_t OpcodeOffset = *OffsetPtr;
805     uint8_t Opcode = TableData.getU8(Cursor);
806     size_t RowCount = Rows.size();
807 
808     if (Cursor && Verbose)
809       *OS << format("%02.02" PRIx8 " ", Opcode);
810 
811     if (Opcode == 0) {
812       // Extended Opcodes always start with a zero opcode followed by
813       // a uleb128 length so you can skip ones you don't know about
814       uint64_t Len = TableData.getULEB128(Cursor);
815       uint64_t ExtOffset = Cursor.tell();
816 
817       // Tolerate zero-length; assume length is correct and soldier on.
818       if (Len == 0) {
819         if (Cursor && Verbose)
820           *OS << "Badly formed extended line op (length 0)\n";
821         if (!Cursor) {
822           if (Verbose)
823             *OS << "\n";
824           RecoverableErrorHandler(Cursor.takeError());
825         }
826         *OffsetPtr = Cursor.tell();
827         continue;
828       }
829 
830       uint8_t SubOpcode = TableData.getU8(Cursor);
831       // OperandOffset will be the same as ExtOffset, if it was not possible to
832       // read the SubOpcode.
833       uint64_t OperandOffset = Cursor.tell();
834       if (Verbose)
835         *OS << LNExtendedString(SubOpcode);
836       switch (SubOpcode) {
837       case DW_LNE_end_sequence:
838         // Set the end_sequence register of the state machine to true and
839         // append a row to the matrix using the current values of the
840         // state-machine registers. Then reset the registers to the initial
841         // values specified above. Every statement program sequence must end
842         // with a DW_LNE_end_sequence instruction which creates a row whose
843         // address is that of the byte after the last target machine instruction
844         // of the sequence.
845         State.Row.EndSequence = true;
846         // No need to test the Cursor is valid here, since it must be to get
847         // into this code path - if it were invalid, the default case would be
848         // followed.
849         EmitRow();
850         State.resetRowAndSequence();
851         break;
852 
853       case DW_LNE_set_address:
854         // Takes a single relocatable address as an operand. The size of the
855         // operand is the size appropriate to hold an address on the target
856         // machine. Set the address register to the value given by the
857         // relocatable address. All of the other statement program opcodes
858         // that affect the address register add a delta to it. This instruction
859         // stores a relocatable value into it instead.
860         //
861         // Make sure the extractor knows the address size.  If not, infer it
862         // from the size of the operand.
863         {
864           uint8_t ExtractorAddressSize = TableData.getAddressSize();
865           uint64_t OpcodeAddressSize = Len - 1;
866           if (ExtractorAddressSize != OpcodeAddressSize &&
867               ExtractorAddressSize != 0)
868             RecoverableErrorHandler(createStringError(
869                 errc::invalid_argument,
870                 "mismatching address size at offset 0x%8.8" PRIx64
871                 " expected 0x%2.2" PRIx8 " found 0x%2.2" PRIx64,
872                 ExtOffset, ExtractorAddressSize, Len - 1));
873 
874           // Assume that the line table is correct and temporarily override the
875           // address size. If the size is unsupported, give up trying to read
876           // the address and continue to the next opcode.
877           if (OpcodeAddressSize != 1 && OpcodeAddressSize != 2 &&
878               OpcodeAddressSize != 4 && OpcodeAddressSize != 8) {
879             RecoverableErrorHandler(createStringError(
880                 errc::invalid_argument,
881                 "address size 0x%2.2" PRIx64
882                 " of DW_LNE_set_address opcode at offset 0x%8.8" PRIx64
883                 " is unsupported",
884                 OpcodeAddressSize, ExtOffset));
885             TableData.skip(Cursor, OpcodeAddressSize);
886           } else {
887             TableData.setAddressSize(OpcodeAddressSize);
888             State.Row.Address.Address = TableData.getRelocatedAddress(
889                 Cursor, &State.Row.Address.SectionIndex);
890 
891             uint64_t Tombstone =
892                 dwarf::computeTombstoneAddress(OpcodeAddressSize);
893             TombstonedAddress = State.Row.Address.Address == Tombstone;
894 
895             // Restore the address size if the extractor already had it.
896             if (ExtractorAddressSize != 0)
897               TableData.setAddressSize(ExtractorAddressSize);
898           }
899 
900           if (Cursor && Verbose) {
901             *OS << " (";
902             DWARFFormValue::dumpAddress(*OS, OpcodeAddressSize, State.Row.Address.Address);
903             *OS << ')';
904           }
905         }
906         break;
907 
908       case DW_LNE_define_file:
909         // Takes 4 arguments. The first is a null terminated string containing
910         // a source file name. The second is an unsigned LEB128 number
911         // representing the directory index of the directory in which the file
912         // was found. The third is an unsigned LEB128 number representing the
913         // time of last modification of the file. The fourth is an unsigned
914         // LEB128 number representing the length in bytes of the file. The time
915         // and length fields may contain LEB128(0) if the information is not
916         // available.
917         //
918         // The directory index represents an entry in the include_directories
919         // section of the statement program prologue. The index is LEB128(0)
920         // if the file was found in the current directory of the compilation,
921         // LEB128(1) if it was found in the first directory in the
922         // include_directories section, and so on. The directory index is
923         // ignored for file names that represent full path names.
924         //
925         // The files are numbered, starting at 1, in the order in which they
926         // appear; the names in the prologue come before names defined by
927         // the DW_LNE_define_file instruction. These numbers are used in the
928         // the file register of the state machine.
929         {
930           FileNameEntry FileEntry;
931           const char *Name = TableData.getCStr(Cursor);
932           FileEntry.Name =
933               DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name);
934           FileEntry.DirIdx = TableData.getULEB128(Cursor);
935           FileEntry.ModTime = TableData.getULEB128(Cursor);
936           FileEntry.Length = TableData.getULEB128(Cursor);
937           Prologue.FileNames.push_back(FileEntry);
938           if (Cursor && Verbose)
939             *OS << " (" << Name << ", dir=" << FileEntry.DirIdx << ", mod_time="
940                 << format("(0x%16.16" PRIx64 ")", FileEntry.ModTime)
941                 << ", length=" << FileEntry.Length << ")";
942         }
943         break;
944 
945       case DW_LNE_set_discriminator:
946         State.Row.Discriminator = TableData.getULEB128(Cursor);
947         if (Cursor && Verbose)
948           *OS << " (" << State.Row.Discriminator << ")";
949         break;
950 
951       default:
952         if (Cursor && Verbose)
953           *OS << format("Unrecognized extended op 0x%02.02" PRIx8, SubOpcode)
954               << format(" length %" PRIx64, Len);
955         // Len doesn't include the zero opcode byte or the length itself, but
956         // it does include the sub_opcode, so we have to adjust for that.
957         TableData.skip(Cursor, Len - 1);
958         break;
959       }
960       // Make sure the length as recorded in the table and the standard length
961       // for the opcode match. If they don't, continue from the end as claimed
962       // by the table. Similarly, continue from the claimed end in the event of
963       // a parsing error.
964       uint64_t End = ExtOffset + Len;
965       if (Cursor && Cursor.tell() != End)
966         RecoverableErrorHandler(createStringError(
967             errc::illegal_byte_sequence,
968             "unexpected line op length at offset 0x%8.8" PRIx64
969             " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx64,
970             ExtOffset, Len, Cursor.tell() - ExtOffset));
971       if (!Cursor && Verbose) {
972         DWARFDataExtractor::Cursor ByteCursor(OperandOffset);
973         uint8_t Byte = TableData.getU8(ByteCursor);
974         if (ByteCursor) {
975           *OS << " (<parsing error>";
976           do {
977             *OS << format(" %2.2" PRIx8, Byte);
978             Byte = TableData.getU8(ByteCursor);
979           } while (ByteCursor);
980           *OS << ")";
981         }
982 
983         // The only parse failure in this case should be if the end was reached.
984         // In that case, throw away the error, as the main Cursor's error will
985         // be sufficient.
986         consumeError(ByteCursor.takeError());
987       }
988       *OffsetPtr = End;
989     } else if (Opcode < Prologue.OpcodeBase) {
990       if (Verbose)
991         *OS << LNStandardString(Opcode);
992       switch (Opcode) {
993       // Standard Opcodes
994       case DW_LNS_copy:
995         // Takes no arguments. Append a row to the matrix using the
996         // current values of the state-machine registers.
997         EmitRow();
998         break;
999 
1000       case DW_LNS_advance_pc:
1001         // Takes a single unsigned LEB128 operand, multiplies it by the
1002         // min_inst_length field of the prologue, and adds the
1003         // result to the address register of the state machine.
1004         if (Optional<uint64_t> Operand =
1005                 parseULEB128<uint64_t>(TableData, Cursor)) {
1006           uint64_t AddrOffset =
1007               State.advanceAddr(*Operand, Opcode, OpcodeOffset);
1008           if (Verbose)
1009             *OS << " (" << AddrOffset << ")";
1010         }
1011         break;
1012 
1013       case DW_LNS_advance_line:
1014         // Takes a single signed LEB128 operand and adds that value to
1015         // the line register of the state machine.
1016         {
1017           int64_t LineDelta = TableData.getSLEB128(Cursor);
1018           if (Cursor) {
1019             State.Row.Line += LineDelta;
1020             if (Verbose)
1021               *OS << " (" << State.Row.Line << ")";
1022           }
1023         }
1024         break;
1025 
1026       case DW_LNS_set_file:
1027         // Takes a single unsigned LEB128 operand and stores it in the file
1028         // register of the state machine.
1029         if (Optional<uint16_t> File =
1030                 parseULEB128<uint16_t>(TableData, Cursor)) {
1031           State.Row.File = *File;
1032           if (Verbose)
1033             *OS << " (" << State.Row.File << ")";
1034         }
1035         break;
1036 
1037       case DW_LNS_set_column:
1038         // Takes a single unsigned LEB128 operand and stores it in the
1039         // column register of the state machine.
1040         if (Optional<uint16_t> Column =
1041                 parseULEB128<uint16_t>(TableData, Cursor)) {
1042           State.Row.Column = *Column;
1043           if (Verbose)
1044             *OS << " (" << State.Row.Column << ")";
1045         }
1046         break;
1047 
1048       case DW_LNS_negate_stmt:
1049         // Takes no arguments. Set the is_stmt register of the state
1050         // machine to the logical negation of its current value.
1051         State.Row.IsStmt = !State.Row.IsStmt;
1052         break;
1053 
1054       case DW_LNS_set_basic_block:
1055         // Takes no arguments. Set the basic_block register of the
1056         // state machine to true
1057         State.Row.BasicBlock = true;
1058         break;
1059 
1060       case DW_LNS_const_add_pc:
1061         // Takes no arguments. Add to the address register of the state
1062         // machine the address increment value corresponding to special
1063         // opcode 255. The motivation for DW_LNS_const_add_pc is this:
1064         // when the statement program needs to advance the address by a
1065         // small amount, it can use a single special opcode, which occupies
1066         // a single byte. When it needs to advance the address by up to
1067         // twice the range of the last special opcode, it can use
1068         // DW_LNS_const_add_pc followed by a special opcode, for a total
1069         // of two bytes. Only if it needs to advance the address by more
1070         // than twice that range will it need to use both DW_LNS_advance_pc
1071         // and a special opcode, requiring three or more bytes.
1072         {
1073           uint64_t AddrOffset =
1074               State.advanceAddrForOpcode(Opcode, OpcodeOffset).AddrDelta;
1075           if (Verbose)
1076             *OS << format(" (0x%16.16" PRIx64 ")", AddrOffset);
1077         }
1078         break;
1079 
1080       case DW_LNS_fixed_advance_pc:
1081         // Takes a single uhalf operand. Add to the address register of
1082         // the state machine the value of the (unencoded) operand. This
1083         // is the only extended opcode that takes an argument that is not
1084         // a variable length number. The motivation for DW_LNS_fixed_advance_pc
1085         // is this: existing assemblers cannot emit DW_LNS_advance_pc or
1086         // special opcodes because they cannot encode LEB128 numbers or
1087         // judge when the computation of a special opcode overflows and
1088         // requires the use of DW_LNS_advance_pc. Such assemblers, however,
1089         // can use DW_LNS_fixed_advance_pc instead, sacrificing compression.
1090         {
1091           uint16_t PCOffset =
1092               TableData.getRelocatedValue(Cursor, 2);
1093           if (Cursor) {
1094             State.Row.Address.Address += PCOffset;
1095             if (Verbose)
1096               *OS << format(" (0x%4.4" PRIx16 ")", PCOffset);
1097           }
1098         }
1099         break;
1100 
1101       case DW_LNS_set_prologue_end:
1102         // Takes no arguments. Set the prologue_end register of the
1103         // state machine to true
1104         State.Row.PrologueEnd = true;
1105         break;
1106 
1107       case DW_LNS_set_epilogue_begin:
1108         // Takes no arguments. Set the basic_block register of the
1109         // state machine to true
1110         State.Row.EpilogueBegin = true;
1111         break;
1112 
1113       case DW_LNS_set_isa:
1114         // Takes a single unsigned LEB128 operand and stores it in the
1115         // ISA register of the state machine.
1116         if (Optional<uint8_t> Isa = parseULEB128<uint8_t>(TableData, Cursor)) {
1117           State.Row.Isa = *Isa;
1118           if (Verbose)
1119             *OS << " (" << (uint64_t)State.Row.Isa << ")";
1120         }
1121         break;
1122 
1123       default:
1124         // Handle any unknown standard opcodes here. We know the lengths
1125         // of such opcodes because they are specified in the prologue
1126         // as a multiple of LEB128 operands for each opcode.
1127         {
1128           assert(Opcode - 1U < Prologue.StandardOpcodeLengths.size());
1129           if (Verbose)
1130             *OS << "Unrecognized standard opcode";
1131           uint8_t OpcodeLength = Prologue.StandardOpcodeLengths[Opcode - 1];
1132           std::vector<uint64_t> Operands;
1133           for (uint8_t I = 0; I < OpcodeLength; ++I) {
1134             if (Optional<uint64_t> Value =
1135                     parseULEB128<uint64_t>(TableData, Cursor))
1136               Operands.push_back(*Value);
1137             else
1138               break;
1139           }
1140           if (Verbose && !Operands.empty()) {
1141             *OS << " (operands: ";
1142             bool First = true;
1143             for (uint64_t Value : Operands) {
1144               if (!First)
1145                 *OS << ", ";
1146               First = false;
1147               *OS << format("0x%16.16" PRIx64, Value);
1148             }
1149             if (Verbose)
1150               *OS << ')';
1151           }
1152         }
1153         break;
1154       }
1155 
1156       *OffsetPtr = Cursor.tell();
1157     } else {
1158       // Special Opcodes.
1159       ParsingState::AddrAndLineDelta Delta =
1160           State.handleSpecialOpcode(Opcode, OpcodeOffset);
1161 
1162       if (Verbose)
1163         *OS << "address += " << Delta.Address << ",  line += " << Delta.Line;
1164       EmitRow();
1165       *OffsetPtr = Cursor.tell();
1166     }
1167 
1168     // When a row is added to the matrix, it is also dumped, which includes a
1169     // new line already, so don't add an extra one.
1170     if (Verbose && Rows.size() == RowCount)
1171       *OS << "\n";
1172 
1173     // Most parse failures other than when parsing extended opcodes are due to
1174     // failures to read ULEBs. Bail out of parsing, since we don't know where to
1175     // continue reading from as there is no stated length for such byte
1176     // sequences. Print the final trailing new line if needed before doing so.
1177     if (!Cursor && Opcode != 0) {
1178       if (Verbose)
1179         *OS << "\n";
1180       return Cursor.takeError();
1181     }
1182 
1183     if (!Cursor)
1184       RecoverableErrorHandler(Cursor.takeError());
1185   }
1186 
1187   if (!State.Sequence.Empty)
1188     RecoverableErrorHandler(createStringError(
1189         errc::illegal_byte_sequence,
1190         "last sequence in debug line table at offset 0x%8.8" PRIx64
1191         " is not terminated",
1192         DebugLineOffset));
1193 
1194   // Sort all sequences so that address lookup will work faster.
1195   if (!Sequences.empty()) {
1196     llvm::sort(Sequences, Sequence::orderByHighPC);
1197     // Note: actually, instruction address ranges of sequences should not
1198     // overlap (in shared objects and executables). If they do, the address
1199     // lookup would still work, though, but result would be ambiguous.
1200     // We don't report warning in this case. For example,
1201     // sometimes .so compiled from multiple object files contains a few
1202     // rudimentary sequences for address ranges [0x0, 0xsomething).
1203   }
1204 
1205   // Terminate the table with a final blank line to clearly delineate it from
1206   // later dumps.
1207   if (OS)
1208     *OS << "\n";
1209 
1210   return Error::success();
1211 }
1212 
1213 uint32_t DWARFDebugLine::LineTable::findRowInSeq(
1214     const DWARFDebugLine::Sequence &Seq,
1215     object::SectionedAddress Address) const {
1216   if (!Seq.containsPC(Address))
1217     return UnknownRowIndex;
1218   assert(Seq.SectionIndex == Address.SectionIndex);
1219   // In some cases, e.g. first instruction in a function, the compiler generates
1220   // two entries, both with the same address. We want the last one.
1221   //
1222   // In general we want a non-empty range: the last row whose address is less
1223   // than or equal to Address. This can be computed as upper_bound - 1.
1224   DWARFDebugLine::Row Row;
1225   Row.Address = Address;
1226   RowIter FirstRow = Rows.begin() + Seq.FirstRowIndex;
1227   RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
1228   assert(FirstRow->Address.Address <= Row.Address.Address &&
1229          Row.Address.Address < LastRow[-1].Address.Address);
1230   RowIter RowPos = std::upper_bound(FirstRow + 1, LastRow - 1, Row,
1231                                     DWARFDebugLine::Row::orderByAddress) -
1232                    1;
1233   assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
1234   return RowPos - Rows.begin();
1235 }
1236 
1237 uint32_t DWARFDebugLine::LineTable::lookupAddress(
1238     object::SectionedAddress Address) const {
1239 
1240   // Search for relocatable addresses
1241   uint32_t Result = lookupAddressImpl(Address);
1242 
1243   if (Result != UnknownRowIndex ||
1244       Address.SectionIndex == object::SectionedAddress::UndefSection)
1245     return Result;
1246 
1247   // Search for absolute addresses
1248   Address.SectionIndex = object::SectionedAddress::UndefSection;
1249   return lookupAddressImpl(Address);
1250 }
1251 
1252 uint32_t DWARFDebugLine::LineTable::lookupAddressImpl(
1253     object::SectionedAddress Address) const {
1254   // First, find an instruction sequence containing the given address.
1255   DWARFDebugLine::Sequence Sequence;
1256   Sequence.SectionIndex = Address.SectionIndex;
1257   Sequence.HighPC = Address.Address;
1258   SequenceIter It = llvm::upper_bound(Sequences, Sequence,
1259                                       DWARFDebugLine::Sequence::orderByHighPC);
1260   if (It == Sequences.end() || It->SectionIndex != Address.SectionIndex)
1261     return UnknownRowIndex;
1262   return findRowInSeq(*It, Address);
1263 }
1264 
1265 bool DWARFDebugLine::LineTable::lookupAddressRange(
1266     object::SectionedAddress Address, uint64_t Size,
1267     std::vector<uint32_t> &Result) const {
1268 
1269   // Search for relocatable addresses
1270   if (lookupAddressRangeImpl(Address, Size, Result))
1271     return true;
1272 
1273   if (Address.SectionIndex == object::SectionedAddress::UndefSection)
1274     return false;
1275 
1276   // Search for absolute addresses
1277   Address.SectionIndex = object::SectionedAddress::UndefSection;
1278   return lookupAddressRangeImpl(Address, Size, Result);
1279 }
1280 
1281 bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
1282     object::SectionedAddress Address, uint64_t Size,
1283     std::vector<uint32_t> &Result) const {
1284   if (Sequences.empty())
1285     return false;
1286   uint64_t EndAddr = Address.Address + Size;
1287   // First, find an instruction sequence containing the given address.
1288   DWARFDebugLine::Sequence Sequence;
1289   Sequence.SectionIndex = Address.SectionIndex;
1290   Sequence.HighPC = Address.Address;
1291   SequenceIter LastSeq = Sequences.end();
1292   SequenceIter SeqPos = llvm::upper_bound(
1293       Sequences, Sequence, DWARFDebugLine::Sequence::orderByHighPC);
1294   if (SeqPos == LastSeq || !SeqPos->containsPC(Address))
1295     return false;
1296 
1297   SequenceIter StartPos = SeqPos;
1298 
1299   // Add the rows from the first sequence to the vector, starting with the
1300   // index we just calculated
1301 
1302   while (SeqPos != LastSeq && SeqPos->LowPC < EndAddr) {
1303     const DWARFDebugLine::Sequence &CurSeq = *SeqPos;
1304     // For the first sequence, we need to find which row in the sequence is the
1305     // first in our range.
1306     uint32_t FirstRowIndex = CurSeq.FirstRowIndex;
1307     if (SeqPos == StartPos)
1308       FirstRowIndex = findRowInSeq(CurSeq, Address);
1309 
1310     // Figure out the last row in the range.
1311     uint32_t LastRowIndex =
1312         findRowInSeq(CurSeq, {EndAddr - 1, Address.SectionIndex});
1313     if (LastRowIndex == UnknownRowIndex)
1314       LastRowIndex = CurSeq.LastRowIndex - 1;
1315 
1316     assert(FirstRowIndex != UnknownRowIndex);
1317     assert(LastRowIndex != UnknownRowIndex);
1318 
1319     for (uint32_t I = FirstRowIndex; I <= LastRowIndex; ++I) {
1320       Result.push_back(I);
1321     }
1322 
1323     ++SeqPos;
1324   }
1325 
1326   return true;
1327 }
1328 
1329 Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
1330                                                                 FileLineInfoKind Kind) const {
1331   if (Kind == FileLineInfoKind::None || !Prologue.hasFileAtIndex(FileIndex))
1332     return None;
1333   const FileNameEntry &Entry = Prologue.getFileNameEntry(FileIndex);
1334   if (Optional<const char *> source = Entry.Source.getAsCString())
1335     return StringRef(*source);
1336   return None;
1337 }
1338 
1339 static bool isPathAbsoluteOnWindowsOrPosix(const Twine &Path) {
1340   // Debug info can contain paths from any OS, not necessarily
1341   // an OS we're currently running on. Moreover different compilation units can
1342   // be compiled on different operating systems and linked together later.
1343   return sys::path::is_absolute(Path, sys::path::Style::posix) ||
1344          sys::path::is_absolute(Path, sys::path::Style::windows);
1345 }
1346 
1347 bool DWARFDebugLine::Prologue::getFileNameByIndex(
1348     uint64_t FileIndex, StringRef CompDir, FileLineInfoKind Kind,
1349     std::string &Result, sys::path::Style Style) const {
1350   if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
1351     return false;
1352   const FileNameEntry &Entry = getFileNameEntry(FileIndex);
1353   Optional<const char *> Name = Entry.Name.getAsCString();
1354   if (!Name)
1355     return false;
1356   StringRef FileName = *Name;
1357   if (Kind == FileLineInfoKind::RawValue ||
1358       isPathAbsoluteOnWindowsOrPosix(FileName)) {
1359     Result = std::string(FileName);
1360     return true;
1361   }
1362   if (Kind == FileLineInfoKind::BaseNameOnly) {
1363     Result = std::string(llvm::sys::path::filename(FileName));
1364     return true;
1365   }
1366 
1367   SmallString<16> FilePath;
1368   StringRef IncludeDir;
1369   // Be defensive about the contents of Entry.
1370   if (getVersion() >= 5) {
1371     // DirIdx 0 is the compilation directory, so don't include it for
1372     // relative names.
1373     if ((Entry.DirIdx != 0 || Kind != FileLineInfoKind::RelativeFilePath) &&
1374         Entry.DirIdx < IncludeDirectories.size())
1375       IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
1376   } else {
1377     if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
1378       IncludeDir =
1379           IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();
1380   }
1381 
1382   // For absolute paths only, include the compilation directory of compile unit.
1383   // We know that FileName is not absolute, the only way to have an absolute
1384   // path at this point would be if IncludeDir is absolute.
1385   if (Kind == FileLineInfoKind::AbsoluteFilePath && !CompDir.empty() &&
1386       !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
1387     sys::path::append(FilePath, Style, CompDir);
1388 
1389   assert((Kind == FileLineInfoKind::AbsoluteFilePath ||
1390           Kind == FileLineInfoKind::RelativeFilePath) &&
1391          "invalid FileLineInfo Kind");
1392 
1393   // sys::path::append skips empty strings.
1394   sys::path::append(FilePath, Style, IncludeDir, FileName);
1395   Result = std::string(FilePath.str());
1396   return true;
1397 }
1398 
1399 bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(
1400     object::SectionedAddress Address, const char *CompDir,
1401     FileLineInfoKind Kind, DILineInfo &Result) const {
1402   // Get the index of row we're looking for in the line table.
1403   uint32_t RowIndex = lookupAddress(Address);
1404   if (RowIndex == -1U)
1405     return false;
1406   // Take file number and line/column from the row.
1407   const auto &Row = Rows[RowIndex];
1408   if (!getFileNameByIndex(Row.File, CompDir, Kind, Result.FileName))
1409     return false;
1410   Result.Line = Row.Line;
1411   Result.Column = Row.Column;
1412   Result.Discriminator = Row.Discriminator;
1413   Result.Source = getSourceByIndex(Row.File, Kind);
1414   return true;
1415 }
1416 
1417 // We want to supply the Unit associated with a .debug_line[.dwo] table when
1418 // we dump it, if possible, but still dump the table even if there isn't a Unit.
1419 // Therefore, collect up handles on all the Units that point into the
1420 // line-table section.
1421 static DWARFDebugLine::SectionParser::LineToUnitMap
1422 buildLineToUnitMap(DWARFUnitVector::iterator_range Units) {
1423   DWARFDebugLine::SectionParser::LineToUnitMap LineToUnit;
1424   for (const auto &U : Units)
1425     if (auto CUDIE = U->getUnitDIE())
1426       if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list)))
1427         LineToUnit.insert(std::make_pair(*StmtOffset, &*U));
1428   return LineToUnit;
1429 }
1430 
1431 DWARFDebugLine::SectionParser::SectionParser(
1432     DWARFDataExtractor &Data, const DWARFContext &C,
1433     DWARFUnitVector::iterator_range Units)
1434     : DebugLineData(Data), Context(C) {
1435   LineToUnit = buildLineToUnitMap(Units);
1436   if (!DebugLineData.isValidOffset(Offset))
1437     Done = true;
1438 }
1439 
1440 bool DWARFDebugLine::Prologue::totalLengthIsValid() const {
1441   return TotalLength != 0u;
1442 }
1443 
1444 DWARFDebugLine::LineTable DWARFDebugLine::SectionParser::parseNext(
1445     function_ref<void(Error)> RecoverableErrorHandler,
1446     function_ref<void(Error)> UnrecoverableErrorHandler, raw_ostream *OS,
1447     bool Verbose) {
1448   assert(DebugLineData.isValidOffset(Offset) &&
1449          "parsing should have terminated");
1450   DWARFUnit *U = prepareToParse(Offset);
1451   uint64_t OldOffset = Offset;
1452   LineTable LT;
1453   if (Error Err = LT.parse(DebugLineData, &Offset, Context, U,
1454                            RecoverableErrorHandler, OS, Verbose))
1455     UnrecoverableErrorHandler(std::move(Err));
1456   moveToNextTable(OldOffset, LT.Prologue);
1457   return LT;
1458 }
1459 
1460 void DWARFDebugLine::SectionParser::skip(
1461     function_ref<void(Error)> RecoverableErrorHandler,
1462     function_ref<void(Error)> UnrecoverableErrorHandler) {
1463   assert(DebugLineData.isValidOffset(Offset) &&
1464          "parsing should have terminated");
1465   DWARFUnit *U = prepareToParse(Offset);
1466   uint64_t OldOffset = Offset;
1467   LineTable LT;
1468   if (Error Err = LT.Prologue.parse(DebugLineData, &Offset,
1469                                     RecoverableErrorHandler, Context, U))
1470     UnrecoverableErrorHandler(std::move(Err));
1471   moveToNextTable(OldOffset, LT.Prologue);
1472 }
1473 
1474 DWARFUnit *DWARFDebugLine::SectionParser::prepareToParse(uint64_t Offset) {
1475   DWARFUnit *U = nullptr;
1476   auto It = LineToUnit.find(Offset);
1477   if (It != LineToUnit.end())
1478     U = It->second;
1479   DebugLineData.setAddressSize(U ? U->getAddressByteSize() : 0);
1480   return U;
1481 }
1482 
1483 void DWARFDebugLine::SectionParser::moveToNextTable(uint64_t OldOffset,
1484                                                     const Prologue &P) {
1485   // If the length field is not valid, we don't know where the next table is, so
1486   // cannot continue to parse. Mark the parser as done, and leave the Offset
1487   // value as it currently is. This will be the end of the bad length field.
1488   if (!P.totalLengthIsValid()) {
1489     Done = true;
1490     return;
1491   }
1492 
1493   Offset = OldOffset + P.TotalLength + P.sizeofTotalLength();
1494   if (!DebugLineData.isValidOffset(Offset)) {
1495     Done = true;
1496   }
1497 }
1498