xref: /llvm-project/llvm/lib/DWARFLinker/Classic/DWARFStreamer.cpp (revision 12285cca5ed713dfd483bd96422a5607b8af0085) 
1 //===- DwarfStreamer.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/DWARFLinker/Classic/DWARFStreamer.h"
10 #include "llvm/CodeGen/NonRelocatableStringpool.h"
11 #include "llvm/DWARFLinker/Classic/DWARFLinkerCompileUnit.h"
12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
13 #include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
14 #include "llvm/MC/MCAsmBackend.h"
15 #include "llvm/MC/MCCodeEmitter.h"
16 #include "llvm/MC/MCDwarf.h"
17 #include "llvm/MC/MCObjectWriter.h"
18 #include "llvm/MC/MCSection.h"
19 #include "llvm/MC/MCStreamer.h"
20 #include "llvm/MC/MCSubtargetInfo.h"
21 #include "llvm/MC/MCTargetOptions.h"
22 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
23 #include "llvm/MC/TargetRegistry.h"
24 #include "llvm/Support/FormatVariadic.h"
25 #include "llvm/Support/LEB128.h"
26 #include "llvm/Target/TargetOptions.h"
27 #include "llvm/TargetParser/Triple.h"
28 
29 using namespace llvm;
30 using namespace dwarf_linker;
31 using namespace dwarf_linker::classic;
32 
33 Expected<std::unique_ptr<DwarfStreamer>> DwarfStreamer::createStreamer(
34     const Triple &TheTriple, DWARFLinkerBase::OutputFileType FileType,
35     raw_pwrite_stream &OutFile, DWARFLinkerBase::MessageHandlerTy Warning) {
36   std::unique_ptr<DwarfStreamer> Streamer =
37       std::make_unique<DwarfStreamer>(FileType, OutFile, Warning);
38   if (Error Err = Streamer->init(TheTriple, "__DWARF"))
39     return std::move(Err);
40 
41   return std::move(Streamer);
42 }
43 
44 Error DwarfStreamer::init(Triple TheTriple,
45                           StringRef Swift5ReflectionSegmentName) {
46   std::string ErrorStr;
47   std::string TripleName;
48 
49   // Get the target.
50   const Target *TheTarget =
51       TargetRegistry::lookupTarget(TripleName, TheTriple, ErrorStr);
52   if (!TheTarget)
53     return createStringError(std::errc::invalid_argument, ErrorStr.c_str());
54 
55   TripleName = TheTriple.getTriple();
56 
57   // Create all the MC Objects.
58   MRI.reset(TheTarget->createMCRegInfo(TripleName));
59   if (!MRI)
60     return createStringError(std::errc::invalid_argument,
61                              "no register info for target %s",
62                              TripleName.c_str());
63 
64   MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
65   MCOptions.AsmVerbose = true;
66   MCOptions.MCUseDwarfDirectory = MCTargetOptions::EnableDwarfDirectory;
67   MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
68   if (!MAI)
69     return createStringError(std::errc::invalid_argument,
70                              "no asm info for target %s", TripleName.c_str());
71 
72   MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
73   if (!MSTI)
74     return createStringError(std::errc::invalid_argument,
75                              "no subtarget info for target %s",
76                              TripleName.c_str());
77 
78   MC.reset(new MCContext(TheTriple, MAI.get(), MRI.get(), MSTI.get(), nullptr,
79                          nullptr, true, Swift5ReflectionSegmentName));
80   MOFI.reset(TheTarget->createMCObjectFileInfo(*MC, /*PIC=*/false, false));
81   MC->setObjectFileInfo(MOFI.get());
82 
83   MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, MCOptions);
84   if (!MAB)
85     return createStringError(std::errc::invalid_argument,
86                              "no asm backend for target %s",
87                              TripleName.c_str());
88 
89   MII.reset(TheTarget->createMCInstrInfo());
90   if (!MII)
91     return createStringError(std::errc::invalid_argument,
92                              "no instr info info for target %s",
93                              TripleName.c_str());
94 
95   MCE = TheTarget->createMCCodeEmitter(*MII, *MC);
96   if (!MCE)
97     return createStringError(std::errc::invalid_argument,
98                              "no code emitter for target %s",
99                              TripleName.c_str());
100 
101   switch (OutFileType) {
102   case DWARFLinker::OutputFileType::Assembly: {
103     MIP = TheTarget->createMCInstPrinter(TheTriple, MAI->getAssemblerDialect(),
104                                          *MAI, *MII, *MRI);
105     MS = TheTarget->createAsmStreamer(
106         *MC, std::make_unique<formatted_raw_ostream>(OutFile), MIP,
107         std::unique_ptr<MCCodeEmitter>(MCE),
108         std::unique_ptr<MCAsmBackend>(MAB));
109     break;
110   }
111   case DWARFLinker::OutputFileType::Object: {
112     MS = TheTarget->createMCObjectStreamer(
113         TheTriple, *MC, std::unique_ptr<MCAsmBackend>(MAB),
114         MAB->createObjectWriter(OutFile), std::unique_ptr<MCCodeEmitter>(MCE),
115         *MSTI);
116     break;
117   }
118   }
119 
120   if (!MS)
121     return createStringError(std::errc::invalid_argument,
122                              "no object streamer for target %s",
123                              TripleName.c_str());
124 
125   // Finally create the AsmPrinter we'll use to emit the DIEs.
126   TM.reset(TheTarget->createTargetMachine(TripleName, "", "", TargetOptions(),
127                                           std::nullopt));
128   if (!TM)
129     return createStringError(std::errc::invalid_argument,
130                              "no target machine for target %s",
131                              TripleName.c_str());
132 
133   Asm.reset(TheTarget->createAsmPrinter(*TM, std::unique_ptr<MCStreamer>(MS)));
134   if (!Asm)
135     return createStringError(std::errc::invalid_argument,
136                              "no asm printer for target %s",
137                              TripleName.c_str());
138   Asm->setDwarfUsesRelocationsAcrossSections(false);
139 
140   RangesSectionSize = 0;
141   RngListsSectionSize = 0;
142   LocSectionSize = 0;
143   LocListsSectionSize = 0;
144   LineSectionSize = 0;
145   FrameSectionSize = 0;
146   DebugInfoSectionSize = 0;
147   MacInfoSectionSize = 0;
148   MacroSectionSize = 0;
149 
150   return Error::success();
151 }
152 
153 void DwarfStreamer::finish() { MS->finish(); }
154 
155 void DwarfStreamer::switchToDebugInfoSection(unsigned DwarfVersion) {
156   MS->switchSection(MOFI->getDwarfInfoSection());
157   MC->setDwarfVersion(DwarfVersion);
158 }
159 
160 /// Emit the compilation unit header for \p Unit in the debug_info section.
161 ///
162 /// A Dwarf 4 section header is encoded as:
163 ///  uint32_t   Unit length (omitting this field)
164 ///  uint16_t   Version
165 ///  uint32_t   Abbreviation table offset
166 ///  uint8_t    Address size
167 /// Leading to a total of 11 bytes.
168 ///
169 /// A Dwarf 5 section header is encoded as:
170 ///  uint32_t   Unit length (omitting this field)
171 ///  uint16_t   Version
172 ///  uint8_t    Unit type
173 ///  uint8_t    Address size
174 ///  uint32_t   Abbreviation table offset
175 /// Leading to a total of 12 bytes.
176 void DwarfStreamer::emitCompileUnitHeader(CompileUnit &Unit,
177                                           unsigned DwarfVersion) {
178   switchToDebugInfoSection(DwarfVersion);
179 
180   /// The start of the unit within its section.
181   Unit.setLabelBegin(Asm->createTempSymbol("cu_begin"));
182   Asm->OutStreamer->emitLabel(Unit.getLabelBegin());
183 
184   // Emit size of content not including length itself. The size has already
185   // been computed in CompileUnit::computeOffsets(). Subtract 4 to that size to
186   // account for the length field.
187   Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset() - 4);
188   Asm->emitInt16(DwarfVersion);
189 
190   if (DwarfVersion >= 5) {
191     Asm->emitInt8(dwarf::DW_UT_compile);
192     Asm->emitInt8(Unit.getOrigUnit().getAddressByteSize());
193     // We share one abbreviations table across all units so it's always at the
194     // start of the section.
195     Asm->emitInt32(0);
196     DebugInfoSectionSize += 12;
197   } else {
198     // We share one abbreviations table across all units so it's always at the
199     // start of the section.
200     Asm->emitInt32(0);
201     Asm->emitInt8(Unit.getOrigUnit().getAddressByteSize());
202     DebugInfoSectionSize += 11;
203   }
204 
205   // Remember this CU.
206   EmittedUnits.push_back({Unit.getUniqueID(), Unit.getLabelBegin()});
207 }
208 
209 /// Emit the \p Abbrevs array as the shared abbreviation table
210 /// for the linked Dwarf file.
211 void DwarfStreamer::emitAbbrevs(
212     const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
213     unsigned DwarfVersion) {
214   MS->switchSection(MOFI->getDwarfAbbrevSection());
215   MC->setDwarfVersion(DwarfVersion);
216   Asm->emitDwarfAbbrevs(Abbrevs);
217 }
218 
219 /// Recursively emit the DIE tree rooted at \p Die.
220 void DwarfStreamer::emitDIE(DIE &Die) {
221   MS->switchSection(MOFI->getDwarfInfoSection());
222   Asm->emitDwarfDIE(Die);
223   DebugInfoSectionSize += Die.getSize();
224 }
225 
226 /// Emit contents of section SecName From Obj.
227 void DwarfStreamer::emitSectionContents(StringRef SecData,
228                                         DebugSectionKind SecKind) {
229   if (SecData.empty())
230     return;
231 
232   if (MCSection *Section = getMCSection(SecKind)) {
233     MS->switchSection(Section);
234 
235     MS->emitBytes(SecData);
236   }
237 }
238 
239 MCSection *DwarfStreamer::getMCSection(DebugSectionKind SecKind) {
240   switch (SecKind) {
241   case DebugSectionKind::DebugInfo:
242     return MC->getObjectFileInfo()->getDwarfInfoSection();
243   case DebugSectionKind::DebugLine:
244     return MC->getObjectFileInfo()->getDwarfLineSection();
245   case DebugSectionKind::DebugFrame:
246     return MC->getObjectFileInfo()->getDwarfFrameSection();
247   case DebugSectionKind::DebugRange:
248     return MC->getObjectFileInfo()->getDwarfRangesSection();
249   case DebugSectionKind::DebugRngLists:
250     return MC->getObjectFileInfo()->getDwarfRnglistsSection();
251   case DebugSectionKind::DebugLoc:
252     return MC->getObjectFileInfo()->getDwarfLocSection();
253   case DebugSectionKind::DebugLocLists:
254     return MC->getObjectFileInfo()->getDwarfLoclistsSection();
255   case DebugSectionKind::DebugARanges:
256     return MC->getObjectFileInfo()->getDwarfARangesSection();
257   case DebugSectionKind::DebugAbbrev:
258     return MC->getObjectFileInfo()->getDwarfAbbrevSection();
259   case DebugSectionKind::DebugMacinfo:
260     return MC->getObjectFileInfo()->getDwarfMacinfoSection();
261   case DebugSectionKind::DebugMacro:
262     return MC->getObjectFileInfo()->getDwarfMacroSection();
263   case DebugSectionKind::DebugAddr:
264     return MC->getObjectFileInfo()->getDwarfAddrSection();
265   case DebugSectionKind::DebugStr:
266     return MC->getObjectFileInfo()->getDwarfStrSection();
267   case DebugSectionKind::DebugLineStr:
268     return MC->getObjectFileInfo()->getDwarfLineStrSection();
269   case DebugSectionKind::DebugStrOffsets:
270     return MC->getObjectFileInfo()->getDwarfStrOffSection();
271   case DebugSectionKind::DebugPubNames:
272     return MC->getObjectFileInfo()->getDwarfPubNamesSection();
273   case DebugSectionKind::DebugPubTypes:
274     return MC->getObjectFileInfo()->getDwarfPubTypesSection();
275   case DebugSectionKind::DebugNames:
276     return MC->getObjectFileInfo()->getDwarfDebugNamesSection();
277   case DebugSectionKind::AppleNames:
278     return MC->getObjectFileInfo()->getDwarfAccelNamesSection();
279   case DebugSectionKind::AppleNamespaces:
280     return MC->getObjectFileInfo()->getDwarfAccelNamespaceSection();
281   case DebugSectionKind::AppleObjC:
282     return MC->getObjectFileInfo()->getDwarfAccelObjCSection();
283   case DebugSectionKind::AppleTypes:
284     return MC->getObjectFileInfo()->getDwarfAccelTypesSection();
285   case DebugSectionKind::NumberOfEnumEntries:
286     llvm_unreachable("Unknown DebugSectionKind value");
287     break;
288   }
289 
290   return nullptr;
291 }
292 
293 /// Emit the debug_str section stored in \p Pool.
294 void DwarfStreamer::emitStrings(const NonRelocatableStringpool &Pool) {
295   Asm->OutStreamer->switchSection(MOFI->getDwarfStrSection());
296   std::vector<DwarfStringPoolEntryRef> Entries = Pool.getEntriesForEmission();
297   for (auto Entry : Entries) {
298     // Emit the string itself.
299     Asm->OutStreamer->emitBytes(Entry.getString());
300     // Emit a null terminator.
301     Asm->emitInt8(0);
302   }
303 }
304 
305 /// Emit the debug string offset table described by \p StringOffsets into the
306 /// .debug_str_offsets table.
307 void DwarfStreamer::emitStringOffsets(
308     const SmallVector<uint64_t> &StringOffsets, uint16_t TargetDWARFVersion) {
309 
310   if (TargetDWARFVersion < 5 || StringOffsets.empty())
311     return;
312 
313   Asm->OutStreamer->switchSection(MOFI->getDwarfStrOffSection());
314 
315   MCSymbol *BeginLabel = Asm->createTempSymbol("Bdebugstroff");
316   MCSymbol *EndLabel = Asm->createTempSymbol("Edebugstroff");
317 
318   // Length.
319   Asm->emitLabelDifference(EndLabel, BeginLabel, sizeof(uint32_t));
320   Asm->OutStreamer->emitLabel(BeginLabel);
321   StrOffsetSectionSize += sizeof(uint32_t);
322 
323   // Version.
324   MS->emitInt16(5);
325   StrOffsetSectionSize += sizeof(uint16_t);
326 
327   // Padding.
328   MS->emitInt16(0);
329   StrOffsetSectionSize += sizeof(uint16_t);
330 
331   for (auto Off : StringOffsets) {
332     Asm->OutStreamer->emitInt32(Off);
333     StrOffsetSectionSize += sizeof(uint32_t);
334   }
335   Asm->OutStreamer->emitLabel(EndLabel);
336 }
337 
338 /// Emit the debug_line_str section stored in \p Pool.
339 void DwarfStreamer::emitLineStrings(const NonRelocatableStringpool &Pool) {
340   Asm->OutStreamer->switchSection(MOFI->getDwarfLineStrSection());
341   std::vector<DwarfStringPoolEntryRef> Entries = Pool.getEntriesForEmission();
342   for (auto Entry : Entries) {
343     // Emit the string itself.
344     Asm->OutStreamer->emitBytes(Entry.getString());
345     // Emit a null terminator.
346     Asm->emitInt8(0);
347   }
348 }
349 
350 void DwarfStreamer::emitDebugNames(DWARF5AccelTable &Table) {
351   if (EmittedUnits.empty())
352     return;
353 
354   // Build up data structures needed to emit this section.
355   std::vector<std::variant<MCSymbol *, uint64_t>> CompUnits;
356   DenseMap<unsigned, unsigned> UniqueIdToCuMap;
357   unsigned Id = 0;
358   for (auto &CU : EmittedUnits) {
359     CompUnits.push_back(CU.LabelBegin);
360     // We might be omitting CUs, so we need to remap them.
361     UniqueIdToCuMap[CU.ID] = Id++;
362   }
363 
364   Asm->OutStreamer->switchSection(MOFI->getDwarfDebugNamesSection());
365   dwarf::Form Form = DIEInteger::BestForm(/*IsSigned*/ false,
366                                           (uint64_t)UniqueIdToCuMap.size() - 1);
367   /// llvm-dwarfutil doesn't support type units + .debug_names right now.
368   // FIXME: add support for type units + .debug_names. For now the behavior is
369   // unsuported.
370   emitDWARF5AccelTable(
371       Asm.get(), Table, CompUnits,
372       [&](const DWARF5AccelTableData &Entry)
373           -> std::optional<DWARF5AccelTable::UnitIndexAndEncoding> {
374         if (UniqueIdToCuMap.size() > 1)
375           return {{UniqueIdToCuMap[Entry.getUnitID()],
376                    {dwarf::DW_IDX_compile_unit, Form}}};
377         return std::nullopt;
378       });
379 }
380 
381 void DwarfStreamer::emitAppleNamespaces(
382     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
383   Asm->OutStreamer->switchSection(MOFI->getDwarfAccelNamespaceSection());
384   auto *SectionBegin = Asm->createTempSymbol("namespac_begin");
385   Asm->OutStreamer->emitLabel(SectionBegin);
386   emitAppleAccelTable(Asm.get(), Table, "namespac", SectionBegin);
387 }
388 
389 void DwarfStreamer::emitAppleNames(
390     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
391   Asm->OutStreamer->switchSection(MOFI->getDwarfAccelNamesSection());
392   auto *SectionBegin = Asm->createTempSymbol("names_begin");
393   Asm->OutStreamer->emitLabel(SectionBegin);
394   emitAppleAccelTable(Asm.get(), Table, "names", SectionBegin);
395 }
396 
397 void DwarfStreamer::emitAppleObjc(
398     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
399   Asm->OutStreamer->switchSection(MOFI->getDwarfAccelObjCSection());
400   auto *SectionBegin = Asm->createTempSymbol("objc_begin");
401   Asm->OutStreamer->emitLabel(SectionBegin);
402   emitAppleAccelTable(Asm.get(), Table, "objc", SectionBegin);
403 }
404 
405 void DwarfStreamer::emitAppleTypes(
406     AccelTable<AppleAccelTableStaticTypeData> &Table) {
407   Asm->OutStreamer->switchSection(MOFI->getDwarfAccelTypesSection());
408   auto *SectionBegin = Asm->createTempSymbol("types_begin");
409   Asm->OutStreamer->emitLabel(SectionBegin);
410   emitAppleAccelTable(Asm.get(), Table, "types", SectionBegin);
411 }
412 
413 /// Emit the swift_ast section stored in \p Buffers.
414 void DwarfStreamer::emitSwiftAST(StringRef Buffer) {
415   MCSection *SwiftASTSection = MOFI->getDwarfSwiftASTSection();
416   SwiftASTSection->setAlignment(Align(32));
417   MS->switchSection(SwiftASTSection);
418   MS->emitBytes(Buffer);
419 }
420 
421 void DwarfStreamer::emitSwiftReflectionSection(
422     llvm::binaryformat::Swift5ReflectionSectionKind ReflSectionKind,
423     StringRef Buffer, uint32_t Alignment, uint32_t Size) {
424   MCSection *ReflectionSection =
425       MOFI->getSwift5ReflectionSection(ReflSectionKind);
426   if (ReflectionSection == nullptr)
427     return;
428   ReflectionSection->setAlignment(Align(Alignment));
429   MS->switchSection(ReflectionSection);
430   MS->emitBytes(Buffer);
431 }
432 
433 void DwarfStreamer::emitDwarfDebugArangesTable(
434     const CompileUnit &Unit, const AddressRanges &LinkedRanges) {
435   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
436 
437   // Make .debug_aranges to be current section.
438   MS->switchSection(MC->getObjectFileInfo()->getDwarfARangesSection());
439 
440   // Emit Header.
441   MCSymbol *BeginLabel = Asm->createTempSymbol("Barange");
442   MCSymbol *EndLabel = Asm->createTempSymbol("Earange");
443 
444   unsigned HeaderSize =
445       sizeof(int32_t) + // Size of contents (w/o this field
446       sizeof(int16_t) + // DWARF ARange version number
447       sizeof(int32_t) + // Offset of CU in the .debug_info section
448       sizeof(int8_t) +  // Pointer Size (in bytes)
449       sizeof(int8_t);   // Segment Size (in bytes)
450 
451   unsigned TupleSize = AddressSize * 2;
452   unsigned Padding = offsetToAlignment(HeaderSize, Align(TupleSize));
453 
454   Asm->emitLabelDifference(EndLabel, BeginLabel, 4); // Arange length
455   Asm->OutStreamer->emitLabel(BeginLabel);
456   Asm->emitInt16(dwarf::DW_ARANGES_VERSION); // Version number
457   Asm->emitInt32(Unit.getStartOffset());     // Corresponding unit's offset
458   Asm->emitInt8(AddressSize);                // Address size
459   Asm->emitInt8(0);                          // Segment size
460 
461   Asm->OutStreamer->emitFill(Padding, 0x0);
462 
463   // Emit linked ranges.
464   for (const AddressRange &Range : LinkedRanges) {
465     MS->emitIntValue(Range.start(), AddressSize);
466     MS->emitIntValue(Range.end() - Range.start(), AddressSize);
467   }
468 
469   // Emit terminator.
470   Asm->OutStreamer->emitIntValue(0, AddressSize);
471   Asm->OutStreamer->emitIntValue(0, AddressSize);
472   Asm->OutStreamer->emitLabel(EndLabel);
473 }
474 
475 void DwarfStreamer::emitDwarfDebugRangesTableFragment(
476     const CompileUnit &Unit, const AddressRanges &LinkedRanges,
477     PatchLocation Patch) {
478   Patch.set(RangesSectionSize);
479 
480   // Make .debug_ranges to be current section.
481   MS->switchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
482   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
483 
484   // Emit ranges.
485   uint64_t BaseAddress = 0;
486   if (std::optional<uint64_t> LowPC = Unit.getLowPc())
487     BaseAddress = *LowPC;
488 
489   for (const AddressRange &Range : LinkedRanges) {
490     MS->emitIntValue(Range.start() - BaseAddress, AddressSize);
491     MS->emitIntValue(Range.end() - BaseAddress, AddressSize);
492 
493     RangesSectionSize += AddressSize;
494     RangesSectionSize += AddressSize;
495   }
496 
497   // Add the terminator entry.
498   MS->emitIntValue(0, AddressSize);
499   MS->emitIntValue(0, AddressSize);
500 
501   RangesSectionSize += AddressSize;
502   RangesSectionSize += AddressSize;
503 }
504 
505 MCSymbol *
506 DwarfStreamer::emitDwarfDebugRangeListHeader(const CompileUnit &Unit) {
507   if (Unit.getOrigUnit().getVersion() < 5)
508     return nullptr;
509 
510   // Make .debug_rnglists to be current section.
511   MS->switchSection(MC->getObjectFileInfo()->getDwarfRnglistsSection());
512 
513   MCSymbol *BeginLabel = Asm->createTempSymbol("Brnglists");
514   MCSymbol *EndLabel = Asm->createTempSymbol("Ernglists");
515   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
516 
517   // Length
518   Asm->emitLabelDifference(EndLabel, BeginLabel, sizeof(uint32_t));
519   Asm->OutStreamer->emitLabel(BeginLabel);
520   RngListsSectionSize += sizeof(uint32_t);
521 
522   // Version.
523   MS->emitInt16(5);
524   RngListsSectionSize += sizeof(uint16_t);
525 
526   // Address size.
527   MS->emitInt8(AddressSize);
528   RngListsSectionSize++;
529 
530   // Seg_size
531   MS->emitInt8(0);
532   RngListsSectionSize++;
533 
534   // Offset entry count
535   MS->emitInt32(0);
536   RngListsSectionSize += sizeof(uint32_t);
537 
538   return EndLabel;
539 }
540 
541 void DwarfStreamer::emitDwarfDebugRangeListFragment(
542     const CompileUnit &Unit, const AddressRanges &LinkedRanges,
543     PatchLocation Patch, DebugDieValuePool &AddrPool) {
544   if (Unit.getOrigUnit().getVersion() < 5) {
545     emitDwarfDebugRangesTableFragment(Unit, LinkedRanges, Patch);
546     return;
547   }
548 
549   emitDwarfDebugRngListsTableFragment(Unit, LinkedRanges, Patch, AddrPool);
550 }
551 
552 void DwarfStreamer::emitDwarfDebugRangeListFooter(const CompileUnit &Unit,
553                                                   MCSymbol *EndLabel) {
554   if (Unit.getOrigUnit().getVersion() < 5)
555     return;
556 
557   // Make .debug_rnglists to be current section.
558   MS->switchSection(MC->getObjectFileInfo()->getDwarfRnglistsSection());
559 
560   if (EndLabel != nullptr)
561     Asm->OutStreamer->emitLabel(EndLabel);
562 }
563 
564 void DwarfStreamer::emitDwarfDebugRngListsTableFragment(
565     const CompileUnit &Unit, const AddressRanges &LinkedRanges,
566     PatchLocation Patch, DebugDieValuePool &AddrPool) {
567   Patch.set(RngListsSectionSize);
568 
569   // Make .debug_rnglists to be current section.
570   MS->switchSection(MC->getObjectFileInfo()->getDwarfRnglistsSection());
571   std::optional<uint64_t> BaseAddress;
572 
573   for (const AddressRange &Range : LinkedRanges) {
574 
575     if (!BaseAddress) {
576       BaseAddress = Range.start();
577 
578       // Emit base address.
579       MS->emitInt8(dwarf::DW_RLE_base_addressx);
580       RngListsSectionSize += 1;
581       RngListsSectionSize +=
582           MS->emitULEB128IntValue(AddrPool.getValueIndex(*BaseAddress));
583     }
584 
585     // Emit type of entry.
586     MS->emitInt8(dwarf::DW_RLE_offset_pair);
587     RngListsSectionSize += 1;
588 
589     // Emit start offset relative to base address.
590     RngListsSectionSize +=
591         MS->emitULEB128IntValue(Range.start() - *BaseAddress);
592 
593     // Emit end offset relative to base address.
594     RngListsSectionSize += MS->emitULEB128IntValue(Range.end() - *BaseAddress);
595   }
596 
597   // Emit the terminator entry.
598   MS->emitInt8(dwarf::DW_RLE_end_of_list);
599   RngListsSectionSize += 1;
600 }
601 
602 /// Emit debug locations(.debug_loc, .debug_loclists) header.
603 MCSymbol *DwarfStreamer::emitDwarfDebugLocListHeader(const CompileUnit &Unit) {
604   if (Unit.getOrigUnit().getVersion() < 5)
605     return nullptr;
606 
607   // Make .debug_loclists the current section.
608   MS->switchSection(MC->getObjectFileInfo()->getDwarfLoclistsSection());
609 
610   MCSymbol *BeginLabel = Asm->createTempSymbol("Bloclists");
611   MCSymbol *EndLabel = Asm->createTempSymbol("Eloclists");
612   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
613 
614   // Length
615   Asm->emitLabelDifference(EndLabel, BeginLabel, sizeof(uint32_t));
616   Asm->OutStreamer->emitLabel(BeginLabel);
617   LocListsSectionSize += sizeof(uint32_t);
618 
619   // Version.
620   MS->emitInt16(5);
621   LocListsSectionSize += sizeof(uint16_t);
622 
623   // Address size.
624   MS->emitInt8(AddressSize);
625   LocListsSectionSize++;
626 
627   // Seg_size
628   MS->emitInt8(0);
629   LocListsSectionSize++;
630 
631   // Offset entry count
632   MS->emitInt32(0);
633   LocListsSectionSize += sizeof(uint32_t);
634 
635   return EndLabel;
636 }
637 
638 /// Emit debug locations(.debug_loc, .debug_loclists) fragment.
639 void DwarfStreamer::emitDwarfDebugLocListFragment(
640     const CompileUnit &Unit,
641     const DWARFLocationExpressionsVector &LinkedLocationExpression,
642     PatchLocation Patch, DebugDieValuePool &AddrPool) {
643   if (Unit.getOrigUnit().getVersion() < 5) {
644     emitDwarfDebugLocTableFragment(Unit, LinkedLocationExpression, Patch);
645     return;
646   }
647 
648   emitDwarfDebugLocListsTableFragment(Unit, LinkedLocationExpression, Patch,
649                                       AddrPool);
650 }
651 
652 /// Emit debug locations(.debug_loc, .debug_loclists) footer.
653 void DwarfStreamer::emitDwarfDebugLocListFooter(const CompileUnit &Unit,
654                                                 MCSymbol *EndLabel) {
655   if (Unit.getOrigUnit().getVersion() < 5)
656     return;
657 
658   // Make .debug_loclists the current section.
659   MS->switchSection(MC->getObjectFileInfo()->getDwarfLoclistsSection());
660 
661   if (EndLabel != nullptr)
662     Asm->OutStreamer->emitLabel(EndLabel);
663 }
664 
665 /// Emit piece of .debug_loc for \p LinkedLocationExpression.
666 void DwarfStreamer::emitDwarfDebugLocTableFragment(
667     const CompileUnit &Unit,
668     const DWARFLocationExpressionsVector &LinkedLocationExpression,
669     PatchLocation Patch) {
670   Patch.set(LocSectionSize);
671 
672   // Make .debug_loc to be current section.
673   MS->switchSection(MC->getObjectFileInfo()->getDwarfLocSection());
674   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
675 
676   // Emit ranges.
677   uint64_t BaseAddress = 0;
678   if (std::optional<uint64_t> LowPC = Unit.getLowPc())
679     BaseAddress = *LowPC;
680 
681   for (const DWARFLocationExpression &LocExpression :
682        LinkedLocationExpression) {
683     if (LocExpression.Range) {
684       MS->emitIntValue(LocExpression.Range->LowPC - BaseAddress, AddressSize);
685       MS->emitIntValue(LocExpression.Range->HighPC - BaseAddress, AddressSize);
686 
687       LocSectionSize += AddressSize;
688       LocSectionSize += AddressSize;
689     }
690 
691     Asm->OutStreamer->emitIntValue(LocExpression.Expr.size(), 2);
692     Asm->OutStreamer->emitBytes(StringRef(
693         (const char *)LocExpression.Expr.data(), LocExpression.Expr.size()));
694     LocSectionSize += LocExpression.Expr.size() + 2;
695   }
696 
697   // Add the terminator entry.
698   MS->emitIntValue(0, AddressSize);
699   MS->emitIntValue(0, AddressSize);
700 
701   LocSectionSize += AddressSize;
702   LocSectionSize += AddressSize;
703 }
704 
705 /// Emit .debug_addr header.
706 MCSymbol *DwarfStreamer::emitDwarfDebugAddrsHeader(const CompileUnit &Unit) {
707 
708   // Make .debug_addr the current section.
709   MS->switchSection(MC->getObjectFileInfo()->getDwarfAddrSection());
710 
711   MCSymbol *BeginLabel = Asm->createTempSymbol("Bdebugaddr");
712   MCSymbol *EndLabel = Asm->createTempSymbol("Edebugaddr");
713   unsigned AddrSize = Unit.getOrigUnit().getAddressByteSize();
714 
715   // Emit length.
716   Asm->emitLabelDifference(EndLabel, BeginLabel, sizeof(uint32_t));
717   Asm->OutStreamer->emitLabel(BeginLabel);
718   AddrSectionSize += sizeof(uint32_t);
719 
720   // Emit version.
721   Asm->emitInt16(5);
722   AddrSectionSize += 2;
723 
724   // Emit address size.
725   Asm->emitInt8(AddrSize);
726   AddrSectionSize += 1;
727 
728   // Emit segment size.
729   Asm->emitInt8(0);
730   AddrSectionSize += 1;
731 
732   return EndLabel;
733 }
734 
735 /// Emit the .debug_addr addresses stored in \p Addrs.
736 void DwarfStreamer::emitDwarfDebugAddrs(const SmallVector<uint64_t> &Addrs,
737                                         uint8_t AddrSize) {
738   Asm->OutStreamer->switchSection(MOFI->getDwarfAddrSection());
739   for (auto Addr : Addrs) {
740     Asm->OutStreamer->emitIntValue(Addr, AddrSize);
741     AddrSectionSize += AddrSize;
742   }
743 }
744 
745 /// Emit .debug_addr footer.
746 void DwarfStreamer::emitDwarfDebugAddrsFooter(const CompileUnit &Unit,
747                                               MCSymbol *EndLabel) {
748 
749   // Make .debug_addr the current section.
750   MS->switchSection(MC->getObjectFileInfo()->getDwarfAddrSection());
751 
752   if (EndLabel != nullptr)
753     Asm->OutStreamer->emitLabel(EndLabel);
754 }
755 
756 /// Emit piece of .debug_loclists for \p LinkedLocationExpression.
757 void DwarfStreamer::emitDwarfDebugLocListsTableFragment(
758     const CompileUnit &Unit,
759     const DWARFLocationExpressionsVector &LinkedLocationExpression,
760     PatchLocation Patch, DebugDieValuePool &AddrPool) {
761   Patch.set(LocListsSectionSize);
762 
763   // Make .debug_loclists the current section.
764   MS->switchSection(MC->getObjectFileInfo()->getDwarfLoclistsSection());
765   std::optional<uint64_t> BaseAddress;
766 
767   for (const DWARFLocationExpression &LocExpression :
768        LinkedLocationExpression) {
769     if (LocExpression.Range) {
770 
771       if (!BaseAddress) {
772 
773         BaseAddress = LocExpression.Range->LowPC;
774 
775         // Emit base address.
776         MS->emitInt8(dwarf::DW_LLE_base_addressx);
777         LocListsSectionSize += 1;
778         LocListsSectionSize +=
779             MS->emitULEB128IntValue(AddrPool.getValueIndex(*BaseAddress));
780       }
781 
782       // Emit type of entry.
783       MS->emitInt8(dwarf::DW_LLE_offset_pair);
784       LocListsSectionSize += 1;
785 
786       // Emit start offset relative to base address.
787       LocListsSectionSize +=
788           MS->emitULEB128IntValue(LocExpression.Range->LowPC - *BaseAddress);
789 
790       // Emit end offset relative to base address.
791       LocListsSectionSize +=
792           MS->emitULEB128IntValue(LocExpression.Range->HighPC - *BaseAddress);
793     } else {
794       // Emit type of entry.
795       MS->emitInt8(dwarf::DW_LLE_default_location);
796       LocListsSectionSize += 1;
797     }
798 
799     LocListsSectionSize += MS->emitULEB128IntValue(LocExpression.Expr.size());
800     Asm->OutStreamer->emitBytes(StringRef(
801         (const char *)LocExpression.Expr.data(), LocExpression.Expr.size()));
802     LocListsSectionSize += LocExpression.Expr.size();
803   }
804 
805   // Emit the terminator entry.
806   MS->emitInt8(dwarf::DW_LLE_end_of_list);
807   LocListsSectionSize += 1;
808 }
809 
810 void DwarfStreamer::emitLineTableForUnit(
811     const DWARFDebugLine::LineTable &LineTable, const CompileUnit &Unit,
812     OffsetsStringPool &DebugStrPool, OffsetsStringPool &DebugLineStrPool) {
813   // Switch to the section where the table will be emitted into.
814   MS->switchSection(MC->getObjectFileInfo()->getDwarfLineSection());
815 
816   MCSymbol *LineStartSym = MC->createTempSymbol();
817   MCSymbol *LineEndSym = MC->createTempSymbol();
818 
819   // unit_length.
820   if (LineTable.Prologue.FormParams.Format == dwarf::DwarfFormat::DWARF64) {
821     MS->emitInt32(dwarf::DW_LENGTH_DWARF64);
822     LineSectionSize += 4;
823   }
824   emitLabelDifference(LineEndSym, LineStartSym,
825                       LineTable.Prologue.FormParams.Format, LineSectionSize);
826   Asm->OutStreamer->emitLabel(LineStartSym);
827 
828   // Emit prologue.
829   emitLineTablePrologue(LineTable.Prologue, DebugStrPool, DebugLineStrPool);
830 
831   // Emit rows.
832   emitLineTableRows(LineTable, LineEndSym,
833                     Unit.getOrigUnit().getAddressByteSize());
834 }
835 
836 void DwarfStreamer::emitLineTablePrologue(const DWARFDebugLine::Prologue &P,
837                                           OffsetsStringPool &DebugStrPool,
838                                           OffsetsStringPool &DebugLineStrPool) {
839   MCSymbol *PrologueStartSym = MC->createTempSymbol();
840   MCSymbol *PrologueEndSym = MC->createTempSymbol();
841 
842   // version (uhalf).
843   MS->emitInt16(P.getVersion());
844   LineSectionSize += 2;
845   if (P.getVersion() == 5) {
846     // address_size (ubyte).
847     MS->emitInt8(P.getAddressSize());
848     LineSectionSize += 1;
849 
850     // segment_selector_size (ubyte).
851     MS->emitInt8(P.SegSelectorSize);
852     LineSectionSize += 1;
853   }
854 
855   // header_length.
856   emitLabelDifference(PrologueEndSym, PrologueStartSym, P.FormParams.Format,
857                       LineSectionSize);
858 
859   Asm->OutStreamer->emitLabel(PrologueStartSym);
860   emitLineTableProloguePayload(P, DebugStrPool, DebugLineStrPool);
861   Asm->OutStreamer->emitLabel(PrologueEndSym);
862 }
863 
864 void DwarfStreamer::emitLineTablePrologueV2IncludeAndFileTable(
865     const DWARFDebugLine::Prologue &P, OffsetsStringPool &DebugStrPool,
866     OffsetsStringPool &DebugLineStrPool) {
867   // include_directories (sequence of path names).
868   for (const DWARFFormValue &Include : P.IncludeDirectories)
869     emitLineTableString(P, Include, DebugStrPool, DebugLineStrPool);
870   // The last entry is followed by a single null byte.
871   MS->emitInt8(0);
872   LineSectionSize += 1;
873 
874   // file_names (sequence of file entries).
875   for (const DWARFDebugLine::FileNameEntry &File : P.FileNames) {
876     // A null-terminated string containing the full or relative path name of a
877     // source file.
878     emitLineTableString(P, File.Name, DebugStrPool, DebugLineStrPool);
879     // An unsigned LEB128 number representing the directory index of a directory
880     // in the include_directories section.
881     LineSectionSize += MS->emitULEB128IntValue(File.DirIdx);
882     // An unsigned LEB128 number representing the (implementation-defined) time
883     // of last modification for the file, or 0 if not available.
884     LineSectionSize += MS->emitULEB128IntValue(File.ModTime);
885     // An unsigned LEB128 number representing the length in bytes of the file,
886     // or 0 if not available.
887     LineSectionSize += MS->emitULEB128IntValue(File.Length);
888   }
889   // The last entry is followed by a single null byte.
890   MS->emitInt8(0);
891   LineSectionSize += 1;
892 }
893 
894 void DwarfStreamer::emitLineTablePrologueV5IncludeAndFileTable(
895     const DWARFDebugLine::Prologue &P, OffsetsStringPool &DebugStrPool,
896     OffsetsStringPool &DebugLineStrPool) {
897   if (P.IncludeDirectories.empty()) {
898     // directory_entry_format_count(ubyte).
899     MS->emitInt8(0);
900     LineSectionSize += 1;
901   } else {
902     // directory_entry_format_count(ubyte).
903     MS->emitInt8(1);
904     LineSectionSize += 1;
905 
906     // directory_entry_format (sequence of ULEB128 pairs).
907     LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_path);
908     LineSectionSize +=
909         MS->emitULEB128IntValue(P.IncludeDirectories[0].getForm());
910   }
911 
912   // directories_count (ULEB128).
913   LineSectionSize += MS->emitULEB128IntValue(P.IncludeDirectories.size());
914   // directories (sequence of directory names).
915   for (auto Include : P.IncludeDirectories)
916     emitLineTableString(P, Include, DebugStrPool, DebugLineStrPool);
917 
918   bool HasChecksums = P.ContentTypes.HasMD5;
919   bool HasInlineSources = P.ContentTypes.HasSource;
920 
921   if (P.FileNames.empty()) {
922     // file_name_entry_format_count (ubyte).
923     MS->emitInt8(0);
924     LineSectionSize += 1;
925   } else {
926     // file_name_entry_format_count (ubyte).
927     MS->emitInt8(2 + (HasChecksums ? 1 : 0) + (HasInlineSources ? 1 : 0));
928     LineSectionSize += 1;
929 
930     // file_name_entry_format (sequence of ULEB128 pairs).
931     auto StrForm = P.FileNames[0].Name.getForm();
932     LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_path);
933     LineSectionSize += MS->emitULEB128IntValue(StrForm);
934 
935     LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_directory_index);
936     LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_FORM_udata);
937 
938     if (HasChecksums) {
939       LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_MD5);
940       LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_FORM_data16);
941     }
942 
943     if (HasInlineSources) {
944       LineSectionSize += MS->emitULEB128IntValue(dwarf::DW_LNCT_LLVM_source);
945       LineSectionSize += MS->emitULEB128IntValue(StrForm);
946     }
947   }
948 
949   // file_names_count (ULEB128).
950   LineSectionSize += MS->emitULEB128IntValue(P.FileNames.size());
951 
952   // file_names (sequence of file name entries).
953   for (auto File : P.FileNames) {
954     emitLineTableString(P, File.Name, DebugStrPool, DebugLineStrPool);
955     LineSectionSize += MS->emitULEB128IntValue(File.DirIdx);
956     if (HasChecksums) {
957       MS->emitBinaryData(
958           StringRef(reinterpret_cast<const char *>(File.Checksum.data()),
959                     File.Checksum.size()));
960       LineSectionSize += File.Checksum.size();
961     }
962     if (HasInlineSources)
963       emitLineTableString(P, File.Source, DebugStrPool, DebugLineStrPool);
964   }
965 }
966 
967 void DwarfStreamer::emitLineTableString(const DWARFDebugLine::Prologue &P,
968                                         const DWARFFormValue &String,
969                                         OffsetsStringPool &DebugStrPool,
970                                         OffsetsStringPool &DebugLineStrPool) {
971   std::optional<const char *> StringVal = dwarf::toString(String);
972   if (!StringVal) {
973     warn("Cann't read string from line table.");
974     return;
975   }
976 
977   switch (String.getForm()) {
978   case dwarf::DW_FORM_string: {
979     StringRef Str = *StringVal;
980     Asm->OutStreamer->emitBytes(Str.data());
981     Asm->emitInt8(0);
982     LineSectionSize += Str.size() + 1;
983   } break;
984   case dwarf::DW_FORM_strp:
985   case dwarf::DW_FORM_line_strp: {
986     DwarfStringPoolEntryRef StringRef =
987         String.getForm() == dwarf::DW_FORM_strp
988             ? DebugStrPool.getEntry(*StringVal)
989             : DebugLineStrPool.getEntry(*StringVal);
990 
991     emitIntOffset(StringRef.getOffset(), P.FormParams.Format, LineSectionSize);
992   } break;
993   default:
994     warn("Unsupported string form inside line table.");
995     break;
996   };
997 }
998 
999 void DwarfStreamer::emitLineTableProloguePayload(
1000     const DWARFDebugLine::Prologue &P, OffsetsStringPool &DebugStrPool,
1001     OffsetsStringPool &DebugLineStrPool) {
1002   // minimum_instruction_length (ubyte).
1003   MS->emitInt8(P.MinInstLength);
1004   LineSectionSize += 1;
1005   if (P.FormParams.Version >= 4) {
1006     // maximum_operations_per_instruction (ubyte).
1007     MS->emitInt8(P.MaxOpsPerInst);
1008     LineSectionSize += 1;
1009   }
1010   // default_is_stmt (ubyte).
1011   MS->emitInt8(P.DefaultIsStmt);
1012   LineSectionSize += 1;
1013   // line_base (sbyte).
1014   MS->emitInt8(P.LineBase);
1015   LineSectionSize += 1;
1016   // line_range (ubyte).
1017   MS->emitInt8(P.LineRange);
1018   LineSectionSize += 1;
1019   // opcode_base (ubyte).
1020   MS->emitInt8(P.OpcodeBase);
1021   LineSectionSize += 1;
1022 
1023   // standard_opcode_lengths (array of ubyte).
1024   for (auto Length : P.StandardOpcodeLengths) {
1025     MS->emitInt8(Length);
1026     LineSectionSize += 1;
1027   }
1028 
1029   if (P.FormParams.Version < 5)
1030     emitLineTablePrologueV2IncludeAndFileTable(P, DebugStrPool,
1031                                                DebugLineStrPool);
1032   else
1033     emitLineTablePrologueV5IncludeAndFileTable(P, DebugStrPool,
1034                                                DebugLineStrPool);
1035 }
1036 
1037 void DwarfStreamer::emitLineTableRows(
1038     const DWARFDebugLine::LineTable &LineTable, MCSymbol *LineEndSym,
1039     unsigned AddressByteSize) {
1040 
1041   MCDwarfLineTableParams Params;
1042   Params.DWARF2LineOpcodeBase = LineTable.Prologue.OpcodeBase;
1043   Params.DWARF2LineBase = LineTable.Prologue.LineBase;
1044   Params.DWARF2LineRange = LineTable.Prologue.LineRange;
1045 
1046   SmallString<128> EncodingBuffer;
1047 
1048   if (LineTable.Rows.empty()) {
1049     // We only have the dummy entry, dsymutil emits an entry with a 0
1050     // address in that case.
1051     MCDwarfLineAddr::encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
1052                             EncodingBuffer);
1053     MS->emitBytes(EncodingBuffer);
1054     LineSectionSize += EncodingBuffer.size();
1055     MS->emitLabel(LineEndSym);
1056     return;
1057   }
1058 
1059   // Line table state machine fields
1060   unsigned FileNum = 1;
1061   unsigned LastLine = 1;
1062   unsigned Column = 0;
1063   unsigned Discriminator = 0;
1064   unsigned IsStatement = 1;
1065   unsigned Isa = 0;
1066   uint64_t Address = -1ULL;
1067 
1068   unsigned RowsSinceLastSequence = 0;
1069 
1070   for (const DWARFDebugLine::Row &Row : LineTable.Rows) {
1071     int64_t AddressDelta;
1072     if (Address == -1ULL) {
1073       MS->emitIntValue(dwarf::DW_LNS_extended_op, 1);
1074       MS->emitULEB128IntValue(AddressByteSize + 1);
1075       MS->emitIntValue(dwarf::DW_LNE_set_address, 1);
1076       MS->emitIntValue(Row.Address.Address, AddressByteSize);
1077       LineSectionSize +=
1078           2 + AddressByteSize + getULEB128Size(AddressByteSize + 1);
1079       AddressDelta = 0;
1080     } else {
1081       AddressDelta =
1082           (Row.Address.Address - Address) / LineTable.Prologue.MinInstLength;
1083     }
1084 
1085     // FIXME: code copied and transformed from MCDwarf.cpp::EmitDwarfLineTable.
1086     // We should find a way to share this code, but the current compatibility
1087     // requirement with classic dsymutil makes it hard. Revisit that once this
1088     // requirement is dropped.
1089 
1090     if (FileNum != Row.File) {
1091       FileNum = Row.File;
1092       MS->emitIntValue(dwarf::DW_LNS_set_file, 1);
1093       MS->emitULEB128IntValue(FileNum);
1094       LineSectionSize += 1 + getULEB128Size(FileNum);
1095     }
1096     if (Column != Row.Column) {
1097       Column = Row.Column;
1098       MS->emitIntValue(dwarf::DW_LNS_set_column, 1);
1099       MS->emitULEB128IntValue(Column);
1100       LineSectionSize += 1 + getULEB128Size(Column);
1101     }
1102     if (Discriminator != Row.Discriminator &&
1103         MS->getContext().getDwarfVersion() >= 4) {
1104       Discriminator = Row.Discriminator;
1105       unsigned Size = getULEB128Size(Discriminator);
1106       MS->emitIntValue(dwarf::DW_LNS_extended_op, 1);
1107       MS->emitULEB128IntValue(Size + 1);
1108       MS->emitIntValue(dwarf::DW_LNE_set_discriminator, 1);
1109       MS->emitULEB128IntValue(Discriminator);
1110       LineSectionSize += /* extended op */ 1 + getULEB128Size(Size + 1) +
1111                          /* discriminator */ 1 + Size;
1112     }
1113     Discriminator = 0;
1114 
1115     if (Isa != Row.Isa) {
1116       Isa = Row.Isa;
1117       MS->emitIntValue(dwarf::DW_LNS_set_isa, 1);
1118       MS->emitULEB128IntValue(Isa);
1119       LineSectionSize += 1 + getULEB128Size(Isa);
1120     }
1121     if (IsStatement != Row.IsStmt) {
1122       IsStatement = Row.IsStmt;
1123       MS->emitIntValue(dwarf::DW_LNS_negate_stmt, 1);
1124       LineSectionSize += 1;
1125     }
1126     if (Row.BasicBlock) {
1127       MS->emitIntValue(dwarf::DW_LNS_set_basic_block, 1);
1128       LineSectionSize += 1;
1129     }
1130 
1131     if (Row.PrologueEnd) {
1132       MS->emitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
1133       LineSectionSize += 1;
1134     }
1135 
1136     if (Row.EpilogueBegin) {
1137       MS->emitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
1138       LineSectionSize += 1;
1139     }
1140 
1141     int64_t LineDelta = int64_t(Row.Line) - LastLine;
1142     if (!Row.EndSequence) {
1143       MCDwarfLineAddr::encode(*MC, Params, LineDelta, AddressDelta,
1144                               EncodingBuffer);
1145       MS->emitBytes(EncodingBuffer);
1146       LineSectionSize += EncodingBuffer.size();
1147       EncodingBuffer.resize(0);
1148       Address = Row.Address.Address;
1149       LastLine = Row.Line;
1150       RowsSinceLastSequence++;
1151     } else {
1152       if (LineDelta) {
1153         MS->emitIntValue(dwarf::DW_LNS_advance_line, 1);
1154         MS->emitSLEB128IntValue(LineDelta);
1155         LineSectionSize += 1 + getSLEB128Size(LineDelta);
1156       }
1157       if (AddressDelta) {
1158         MS->emitIntValue(dwarf::DW_LNS_advance_pc, 1);
1159         MS->emitULEB128IntValue(AddressDelta);
1160         LineSectionSize += 1 + getULEB128Size(AddressDelta);
1161       }
1162       MCDwarfLineAddr::encode(*MC, Params, std::numeric_limits<int64_t>::max(),
1163                               0, EncodingBuffer);
1164       MS->emitBytes(EncodingBuffer);
1165       LineSectionSize += EncodingBuffer.size();
1166       EncodingBuffer.resize(0);
1167       Address = -1ULL;
1168       LastLine = FileNum = IsStatement = 1;
1169       RowsSinceLastSequence = Column = Discriminator = Isa = 0;
1170     }
1171   }
1172 
1173   if (RowsSinceLastSequence) {
1174     MCDwarfLineAddr::encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
1175                             EncodingBuffer);
1176     MS->emitBytes(EncodingBuffer);
1177     LineSectionSize += EncodingBuffer.size();
1178     EncodingBuffer.resize(0);
1179   }
1180 
1181   MS->emitLabel(LineEndSym);
1182 }
1183 
1184 void DwarfStreamer::emitIntOffset(uint64_t Offset, dwarf::DwarfFormat Format,
1185                                   uint64_t &SectionSize) {
1186   uint8_t Size = dwarf::getDwarfOffsetByteSize(Format);
1187   MS->emitIntValue(Offset, Size);
1188   SectionSize += Size;
1189 }
1190 
1191 void DwarfStreamer::emitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1192                                         dwarf::DwarfFormat Format,
1193                                         uint64_t &SectionSize) {
1194   uint8_t Size = dwarf::getDwarfOffsetByteSize(Format);
1195   Asm->emitLabelDifference(Hi, Lo, Size);
1196   SectionSize += Size;
1197 }
1198 
1199 /// Emit the pubnames or pubtypes section contribution for \p
1200 /// Unit into \p Sec. The data is provided in \p Names.
1201 void DwarfStreamer::emitPubSectionForUnit(
1202     MCSection *Sec, StringRef SecName, const CompileUnit &Unit,
1203     const std::vector<CompileUnit::AccelInfo> &Names) {
1204   if (Names.empty())
1205     return;
1206 
1207   // Start the dwarf pubnames section.
1208   Asm->OutStreamer->switchSection(Sec);
1209   MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + SecName + "_begin");
1210   MCSymbol *EndLabel = Asm->createTempSymbol("pub" + SecName + "_end");
1211 
1212   bool HeaderEmitted = false;
1213   // Emit the pubnames for this compilation unit.
1214   for (const auto &Name : Names) {
1215     if (Name.SkipPubSection)
1216       continue;
1217 
1218     if (!HeaderEmitted) {
1219       // Emit the header.
1220       Asm->emitLabelDifference(EndLabel, BeginLabel, 4); // Length
1221       Asm->OutStreamer->emitLabel(BeginLabel);
1222       Asm->emitInt16(dwarf::DW_PUBNAMES_VERSION); // Version
1223       Asm->emitInt32(Unit.getStartOffset());      // Unit offset
1224       Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset()); // Size
1225       HeaderEmitted = true;
1226     }
1227     Asm->emitInt32(Name.Die->getOffset());
1228 
1229     // Emit the string itself.
1230     Asm->OutStreamer->emitBytes(Name.Name.getString());
1231     // Emit a null terminator.
1232     Asm->emitInt8(0);
1233   }
1234 
1235   if (!HeaderEmitted)
1236     return;
1237   Asm->emitInt32(0); // End marker.
1238   Asm->OutStreamer->emitLabel(EndLabel);
1239 }
1240 
1241 /// Emit .debug_pubnames for \p Unit.
1242 void DwarfStreamer::emitPubNamesForUnit(const CompileUnit &Unit) {
1243   emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubNamesSection(),
1244                         "names", Unit, Unit.getPubnames());
1245 }
1246 
1247 /// Emit .debug_pubtypes for \p Unit.
1248 void DwarfStreamer::emitPubTypesForUnit(const CompileUnit &Unit) {
1249   emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubTypesSection(),
1250                         "types", Unit, Unit.getPubtypes());
1251 }
1252 
1253 /// Emit a CIE into the debug_frame section.
1254 void DwarfStreamer::emitCIE(StringRef CIEBytes) {
1255   MS->switchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
1256 
1257   MS->emitBytes(CIEBytes);
1258   FrameSectionSize += CIEBytes.size();
1259 }
1260 
1261 /// Emit a FDE into the debug_frame section. \p FDEBytes
1262 /// contains the FDE data without the length, CIE offset and address
1263 /// which will be replaced with the parameter values.
1264 void DwarfStreamer::emitFDE(uint32_t CIEOffset, uint32_t AddrSize,
1265                             uint64_t Address, StringRef FDEBytes) {
1266   MS->switchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
1267 
1268   MS->emitIntValue(FDEBytes.size() + 4 + AddrSize, 4);
1269   MS->emitIntValue(CIEOffset, 4);
1270   MS->emitIntValue(Address, AddrSize);
1271   MS->emitBytes(FDEBytes);
1272   FrameSectionSize += FDEBytes.size() + 8 + AddrSize;
1273 }
1274 
1275 void DwarfStreamer::emitMacroTables(DWARFContext *Context,
1276                                     const Offset2UnitMap &UnitMacroMap,
1277                                     OffsetsStringPool &StringPool) {
1278   assert(Context != nullptr && "Empty DWARF context");
1279 
1280   // Check for .debug_macinfo table.
1281   if (const DWARFDebugMacro *Table = Context->getDebugMacinfo()) {
1282     MS->switchSection(MC->getObjectFileInfo()->getDwarfMacinfoSection());
1283     emitMacroTableImpl(Table, UnitMacroMap, StringPool, MacInfoSectionSize);
1284   }
1285 
1286   // Check for .debug_macro table.
1287   if (const DWARFDebugMacro *Table = Context->getDebugMacro()) {
1288     MS->switchSection(MC->getObjectFileInfo()->getDwarfMacroSection());
1289     emitMacroTableImpl(Table, UnitMacroMap, StringPool, MacroSectionSize);
1290   }
1291 }
1292 
1293 void DwarfStreamer::emitMacroTableImpl(const DWARFDebugMacro *MacroTable,
1294                                        const Offset2UnitMap &UnitMacroMap,
1295                                        OffsetsStringPool &StringPool,
1296                                        uint64_t &OutOffset) {
1297   bool DefAttributeIsReported = false;
1298   bool UndefAttributeIsReported = false;
1299   bool ImportAttributeIsReported = false;
1300   for (const DWARFDebugMacro::MacroList &List : MacroTable->MacroLists) {
1301     Offset2UnitMap::const_iterator UnitIt = UnitMacroMap.find(List.Offset);
1302     if (UnitIt == UnitMacroMap.end()) {
1303       warn(formatv(
1304           "couldn`t find compile unit for the macro table with offset = {0:x}",
1305           List.Offset));
1306       continue;
1307     }
1308 
1309     // Skip macro table if the unit was not cloned.
1310     DIE *OutputUnitDIE = UnitIt->second->getOutputUnitDIE();
1311     if (OutputUnitDIE == nullptr)
1312       continue;
1313 
1314     // Update macro attribute of cloned compile unit with the proper offset to
1315     // the macro table.
1316     bool hasDWARFv5Header = false;
1317     for (auto &V : OutputUnitDIE->values()) {
1318       if (V.getAttribute() == dwarf::DW_AT_macro_info) {
1319         V = DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset));
1320         break;
1321       } else if (V.getAttribute() == dwarf::DW_AT_macros) {
1322         hasDWARFv5Header = true;
1323         V = DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset));
1324         break;
1325       }
1326     }
1327 
1328     // Write DWARFv5 header.
1329     if (hasDWARFv5Header) {
1330       // Write header version.
1331       MS->emitIntValue(List.Header.Version, sizeof(List.Header.Version));
1332       OutOffset += sizeof(List.Header.Version);
1333 
1334       uint8_t Flags = List.Header.Flags;
1335 
1336       // Check for OPCODE_OPERANDS_TABLE.
1337       if (Flags &
1338           DWARFDebugMacro::HeaderFlagMask::MACRO_OPCODE_OPERANDS_TABLE) {
1339         Flags &= ~DWARFDebugMacro::HeaderFlagMask::MACRO_OPCODE_OPERANDS_TABLE;
1340         warn("opcode_operands_table is not supported yet.");
1341       }
1342 
1343       // Check for DEBUG_LINE_OFFSET.
1344       std::optional<uint64_t> StmtListOffset;
1345       if (Flags & DWARFDebugMacro::HeaderFlagMask::MACRO_DEBUG_LINE_OFFSET) {
1346         // Get offset to the line table from the cloned compile unit.
1347         for (auto &V : OutputUnitDIE->values()) {
1348           if (V.getAttribute() == dwarf::DW_AT_stmt_list) {
1349             StmtListOffset = V.getDIEInteger().getValue();
1350             break;
1351           }
1352         }
1353 
1354         if (!StmtListOffset) {
1355           Flags &= ~DWARFDebugMacro::HeaderFlagMask::MACRO_DEBUG_LINE_OFFSET;
1356           warn("couldn`t find line table for macro table.");
1357         }
1358       }
1359 
1360       // Write flags.
1361       MS->emitIntValue(Flags, sizeof(Flags));
1362       OutOffset += sizeof(Flags);
1363 
1364       // Write offset to line table.
1365       if (StmtListOffset) {
1366         MS->emitIntValue(*StmtListOffset, List.Header.getOffsetByteSize());
1367         OutOffset += List.Header.getOffsetByteSize();
1368       }
1369     }
1370 
1371     // Write macro entries.
1372     for (const DWARFDebugMacro::Entry &MacroEntry : List.Macros) {
1373       if (MacroEntry.Type == 0) {
1374         OutOffset += MS->emitULEB128IntValue(MacroEntry.Type);
1375         continue;
1376       }
1377 
1378       uint8_t MacroType = MacroEntry.Type;
1379       switch (MacroType) {
1380       default: {
1381         bool HasVendorSpecificExtension =
1382             (!hasDWARFv5Header && MacroType == dwarf::DW_MACINFO_vendor_ext) ||
1383             (hasDWARFv5Header && (MacroType >= dwarf::DW_MACRO_lo_user &&
1384                                   MacroType <= dwarf::DW_MACRO_hi_user));
1385 
1386         if (HasVendorSpecificExtension) {
1387           // Write macinfo type.
1388           MS->emitIntValue(MacroType, 1);
1389           OutOffset++;
1390 
1391           // Write vendor extension constant.
1392           OutOffset += MS->emitULEB128IntValue(MacroEntry.ExtConstant);
1393 
1394           // Write vendor extension string.
1395           StringRef String = MacroEntry.ExtStr;
1396           MS->emitBytes(String);
1397           MS->emitIntValue(0, 1);
1398           OutOffset += String.size() + 1;
1399         } else
1400           warn("unknown macro type. skip.");
1401       } break;
1402       // debug_macro and debug_macinfo share some common encodings.
1403       // DW_MACRO_define     == DW_MACINFO_define
1404       // DW_MACRO_undef      == DW_MACINFO_undef
1405       // DW_MACRO_start_file == DW_MACINFO_start_file
1406       // DW_MACRO_end_file   == DW_MACINFO_end_file
1407       // For readibility/uniformity we are using DW_MACRO_*.
1408       case dwarf::DW_MACRO_define:
1409       case dwarf::DW_MACRO_undef: {
1410         // Write macinfo type.
1411         MS->emitIntValue(MacroType, 1);
1412         OutOffset++;
1413 
1414         // Write source line.
1415         OutOffset += MS->emitULEB128IntValue(MacroEntry.Line);
1416 
1417         // Write macro string.
1418         StringRef String = MacroEntry.MacroStr;
1419         MS->emitBytes(String);
1420         MS->emitIntValue(0, 1);
1421         OutOffset += String.size() + 1;
1422       } break;
1423       case dwarf::DW_MACRO_define_strp:
1424       case dwarf::DW_MACRO_undef_strp:
1425       case dwarf::DW_MACRO_define_strx:
1426       case dwarf::DW_MACRO_undef_strx: {
1427         assert(UnitIt->second->getOrigUnit().getVersion() >= 5);
1428 
1429         // DW_MACRO_*_strx forms are not supported currently.
1430         // Convert to *_strp.
1431         switch (MacroType) {
1432         case dwarf::DW_MACRO_define_strx: {
1433           MacroType = dwarf::DW_MACRO_define_strp;
1434           if (!DefAttributeIsReported) {
1435             warn("DW_MACRO_define_strx unsupported yet. Convert to "
1436                  "DW_MACRO_define_strp.");
1437             DefAttributeIsReported = true;
1438           }
1439         } break;
1440         case dwarf::DW_MACRO_undef_strx: {
1441           MacroType = dwarf::DW_MACRO_undef_strp;
1442           if (!UndefAttributeIsReported) {
1443             warn("DW_MACRO_undef_strx unsupported yet. Convert to "
1444                  "DW_MACRO_undef_strp.");
1445             UndefAttributeIsReported = true;
1446           }
1447         } break;
1448         default:
1449           // Nothing to do.
1450           break;
1451         }
1452 
1453         // Write macinfo type.
1454         MS->emitIntValue(MacroType, 1);
1455         OutOffset++;
1456 
1457         // Write source line.
1458         OutOffset += MS->emitULEB128IntValue(MacroEntry.Line);
1459 
1460         // Write macro string.
1461         DwarfStringPoolEntryRef EntryRef =
1462             StringPool.getEntry(MacroEntry.MacroStr);
1463         MS->emitIntValue(EntryRef.getOffset(), List.Header.getOffsetByteSize());
1464         OutOffset += List.Header.getOffsetByteSize();
1465         break;
1466       }
1467       case dwarf::DW_MACRO_start_file: {
1468         // Write macinfo type.
1469         MS->emitIntValue(MacroType, 1);
1470         OutOffset++;
1471         // Write source line.
1472         OutOffset += MS->emitULEB128IntValue(MacroEntry.Line);
1473         // Write source file id.
1474         OutOffset += MS->emitULEB128IntValue(MacroEntry.File);
1475       } break;
1476       case dwarf::DW_MACRO_end_file: {
1477         // Write macinfo type.
1478         MS->emitIntValue(MacroType, 1);
1479         OutOffset++;
1480       } break;
1481       case dwarf::DW_MACRO_import:
1482       case dwarf::DW_MACRO_import_sup: {
1483         if (!ImportAttributeIsReported) {
1484           warn("DW_MACRO_import and DW_MACRO_import_sup are unsupported yet. "
1485                "remove.");
1486           ImportAttributeIsReported = true;
1487         }
1488       } break;
1489       }
1490     }
1491   }
1492 }
1493