1//===- lib/MC/MCContext.cpp - Machine Code Context ------------------------===//
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/MC/MCContext.h"
10#include "llvm/ADT/SmallString.h"
11#include "llvm/ADT/SmallVector.h"
12#include "llvm/ADT/StringMap.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/ADT/Twine.h"
15#include "llvm/BinaryFormat/COFF.h"
16#include "llvm/BinaryFormat/ELF.h"
17#include "llvm/BinaryFormat/Wasm.h"
18#include "llvm/BinaryFormat/XCOFF.h"
19#include "llvm/MC/MCAsmInfo.h"
20#include "llvm/MC/MCCodeView.h"
21#include "llvm/MC/MCDwarf.h"
22#include "llvm/MC/MCExpr.h"
23#include "llvm/MC/MCFragment.h"
24#include "llvm/MC/MCInst.h"
25#include "llvm/MC/MCLabel.h"
26#include "llvm/MC/MCSectionCOFF.h"
27#include "llvm/MC/MCSectionDXContainer.h"
28#include "llvm/MC/MCSectionELF.h"
29#include "llvm/MC/MCSectionGOFF.h"
30#include "llvm/MC/MCSectionMachO.h"
31#include "llvm/MC/MCSectionSPIRV.h"
32#include "llvm/MC/MCSectionWasm.h"
33#include "llvm/MC/MCSectionXCOFF.h"
34#include "llvm/MC/MCStreamer.h"
35#include "llvm/MC/MCSubtargetInfo.h"
36#include "llvm/MC/MCSymbol.h"
37#include "llvm/MC/MCSymbolCOFF.h"
38#include "llvm/MC/MCSymbolELF.h"
39#include "llvm/MC/MCSymbolGOFF.h"
40#include "llvm/MC/MCSymbolMachO.h"
41#include "llvm/MC/MCSymbolWasm.h"
42#include "llvm/MC/MCSymbolXCOFF.h"
43#include "llvm/MC/MCTargetOptions.h"
44#include "llvm/MC/SectionKind.h"
45#include "llvm/Support/Casting.h"
46#include "llvm/Support/CommandLine.h"
47#include "llvm/Support/ErrorHandling.h"
48#include "llvm/Support/MemoryBuffer.h"
49#include "llvm/Support/Path.h"
50#include "llvm/Support/SMLoc.h"
51#include "llvm/Support/SourceMgr.h"
52#include "llvm/Support/raw_ostream.h"
53#include <cassert>
54#include <cstdlib>
55#include <optional>
56#include <tuple>
57#include <utility>
58
59using namespace llvm;
60
61static void defaultDiagHandler(const SMDiagnostic &SMD, bool, const SourceMgr &,
62 std::vector<const MDNode *> &) {
63 SMD.print(ProgName: nullptr, S&: errs());
64}
65
66MCContext::MCContext(const Triple &TheTriple, const MCAsmInfo *mai,
67 const MCRegisterInfo *mri, const MCSubtargetInfo *msti,
68 const SourceMgr *mgr, MCTargetOptions const *TargetOpts,
69 bool DoAutoReset, StringRef Swift5ReflSegmentName)
70 : Swift5ReflectionSegmentName(Swift5ReflSegmentName), TT(TheTriple),
71 SrcMgr(mgr), InlineSrcMgr(nullptr), DiagHandler(defaultDiagHandler),
72 MAI(mai), MRI(mri), MSTI(msti), Symbols(Allocator), UsedNames(Allocator),
73 InlineAsmUsedLabelNames(Allocator),
74 CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0),
75 AutoReset(DoAutoReset), TargetOptions(TargetOpts) {
76 SecureLogFile = TargetOptions ? TargetOptions->AsSecureLogFile : "";
77
78 if (SrcMgr && SrcMgr->getNumBuffers())
79 MainFileName = std::string(SrcMgr->getMemoryBuffer(i: SrcMgr->getMainFileID())
80 ->getBufferIdentifier());
81
82 switch (TheTriple.getObjectFormat()) {
83 case Triple::MachO:
84 Env = IsMachO;
85 break;
86 case Triple::COFF:
87 if (!TheTriple.isOSWindows() && !TheTriple.isUEFI())
88 report_fatal_error(
89 reason: "Cannot initialize MC for non-Windows COFF object files.");
90
91 Env = IsCOFF;
92 break;
93 case Triple::ELF:
94 Env = IsELF;
95 break;
96 case Triple::Wasm:
97 Env = IsWasm;
98 break;
99 case Triple::XCOFF:
100 Env = IsXCOFF;
101 break;
102 case Triple::GOFF:
103 Env = IsGOFF;
104 break;
105 case Triple::DXContainer:
106 Env = IsDXContainer;
107 break;
108 case Triple::SPIRV:
109 Env = IsSPIRV;
110 break;
111 case Triple::UnknownObjectFormat:
112 report_fatal_error(reason: "Cannot initialize MC for unknown object file format.");
113 break;
114 }
115}
116
117MCContext::~MCContext() {
118 if (AutoReset)
119 reset();
120
121 // NOTE: The symbols are all allocated out of a bump pointer allocator,
122 // we don't need to free them here.
123}
124
125void MCContext::initInlineSourceManager() {
126 if (!InlineSrcMgr)
127 InlineSrcMgr.reset(p: new SourceMgr());
128}
129
130//===----------------------------------------------------------------------===//
131// Module Lifetime Management
132//===----------------------------------------------------------------------===//
133
134void MCContext::reset() {
135 SrcMgr = nullptr;
136 InlineSrcMgr.reset();
137 LocInfos.clear();
138 DiagHandler = defaultDiagHandler;
139
140 // Call the destructors so the fragments are freed
141 COFFAllocator.DestroyAll();
142 DXCAllocator.DestroyAll();
143 ELFAllocator.DestroyAll();
144 GOFFAllocator.DestroyAll();
145 MachOAllocator.DestroyAll();
146 WasmAllocator.DestroyAll();
147 XCOFFAllocator.DestroyAll();
148 MCInstAllocator.DestroyAll();
149 SPIRVAllocator.DestroyAll();
150
151 MCSubtargetAllocator.DestroyAll();
152 InlineAsmUsedLabelNames.clear();
153 UsedNames.clear();
154 Symbols.clear();
155 Allocator.Reset();
156 Instances.clear();
157 CompilationDir.clear();
158 MainFileName.clear();
159 MCDwarfLineTablesCUMap.clear();
160 SectionsForRanges.clear();
161 MCGenDwarfLabelEntries.clear();
162 DwarfDebugFlags = StringRef();
163 DwarfCompileUnitID = 0;
164 CurrentDwarfLoc = MCDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0);
165
166 CVContext.reset();
167
168 MachOUniquingMap.clear();
169 ELFUniquingMap.clear();
170 GOFFUniquingMap.clear();
171 COFFUniquingMap.clear();
172 WasmUniquingMap.clear();
173 XCOFFUniquingMap.clear();
174 DXCUniquingMap.clear();
175
176 ELFEntrySizeMap.clear();
177 ELFSeenGenericMergeableSections.clear();
178
179 NextID.clear();
180 AllowTemporaryLabels = true;
181 DwarfLocSeen = false;
182 GenDwarfForAssembly = false;
183 GenDwarfFileNumber = 0;
184
185 HadError = false;
186}
187
188//===----------------------------------------------------------------------===//
189// MCInst Management
190//===----------------------------------------------------------------------===//
191
192MCInst *MCContext::createMCInst() {
193 return new (MCInstAllocator.Allocate()) MCInst;
194}
195
196//===----------------------------------------------------------------------===//
197// Symbol Manipulation
198//===----------------------------------------------------------------------===//
199
200MCSymbol *MCContext::getOrCreateSymbol(const Twine &Name) {
201 SmallString<128> NameSV;
202 StringRef NameRef = Name.toStringRef(Out&: NameSV);
203
204 assert(!NameRef.empty() && "Normal symbols cannot be unnamed!");
205
206 MCSymbol *&Sym = Symbols[NameRef];
207 if (!Sym)
208 Sym = createSymbol(Name: NameRef, AlwaysAddSuffix: false, IsTemporary: false);
209
210 return Sym;
211}
212
213MCSymbol *MCContext::getOrCreateFrameAllocSymbol(const Twine &FuncName,
214 unsigned Idx) {
215 return getOrCreateSymbol(Name: MAI->getPrivateGlobalPrefix() + FuncName +
216 "$frame_escape_" + Twine(Idx));
217}
218
219MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(const Twine &FuncName) {
220 return getOrCreateSymbol(Name: MAI->getPrivateGlobalPrefix() + FuncName +
221 "$parent_frame_offset");
222}
223
224MCSymbol *MCContext::getOrCreateLSDASymbol(const Twine &FuncName) {
225 return getOrCreateSymbol(Name: MAI->getPrivateGlobalPrefix() + "__ehtable$" +
226 FuncName);
227}
228
229MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
230 bool IsTemporary) {
231 static_assert(std::is_trivially_destructible<MCSymbolCOFF>(),
232 "MCSymbol classes must be trivially destructible");
233 static_assert(std::is_trivially_destructible<MCSymbolELF>(),
234 "MCSymbol classes must be trivially destructible");
235 static_assert(std::is_trivially_destructible<MCSymbolMachO>(),
236 "MCSymbol classes must be trivially destructible");
237 static_assert(std::is_trivially_destructible<MCSymbolWasm>(),
238 "MCSymbol classes must be trivially destructible");
239 static_assert(std::is_trivially_destructible<MCSymbolXCOFF>(),
240 "MCSymbol classes must be trivially destructible");
241
242 switch (getObjectFileType()) {
243 case MCContext::IsCOFF:
244 return new (Name, *this) MCSymbolCOFF(Name, IsTemporary);
245 case MCContext::IsELF:
246 return new (Name, *this) MCSymbolELF(Name, IsTemporary);
247 case MCContext::IsGOFF:
248 return new (Name, *this) MCSymbolGOFF(Name, IsTemporary);
249 case MCContext::IsMachO:
250 return new (Name, *this) MCSymbolMachO(Name, IsTemporary);
251 case MCContext::IsWasm:
252 return new (Name, *this) MCSymbolWasm(Name, IsTemporary);
253 case MCContext::IsXCOFF:
254 return createXCOFFSymbolImpl(Name, IsTemporary);
255 case MCContext::IsDXContainer:
256 break;
257 case MCContext::IsSPIRV:
258 return new (Name, *this)
259 MCSymbol(MCSymbol::SymbolKindUnset, Name, IsTemporary);
260 }
261 return new (Name, *this)
262 MCSymbol(MCSymbol::SymbolKindUnset, Name, IsTemporary);
263}
264
265MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
266 bool CanBeUnnamed) {
267 if (CanBeUnnamed && !UseNamesOnTempLabels)
268 return createSymbolImpl(Name: nullptr, IsTemporary: true);
269
270 // Determine whether this is a user written assembler temporary or normal
271 // label, if used.
272 bool IsTemporary = CanBeUnnamed;
273 if (AllowTemporaryLabels && !IsTemporary)
274 IsTemporary = Name.starts_with(Prefix: MAI->getPrivateGlobalPrefix());
275
276 SmallString<128> NewName = Name;
277 bool AddSuffix = AlwaysAddSuffix;
278 unsigned &NextUniqueID = NextID[Name];
279 while (true) {
280 if (AddSuffix) {
281 NewName.resize(N: Name.size());
282 raw_svector_ostream(NewName) << NextUniqueID++;
283 }
284 auto NameEntry = UsedNames.insert(KV: std::make_pair(x: NewName.str(), y: true));
285 if (NameEntry.second || !NameEntry.first->second) {
286 // Ok, we found a name.
287 // Mark it as used for a non-section symbol.
288 NameEntry.first->second = true;
289 // Have the MCSymbol object itself refer to the copy of the string that is
290 // embedded in the UsedNames entry.
291 return createSymbolImpl(Name: &*NameEntry.first, IsTemporary);
292 }
293 assert(IsTemporary && "Cannot rename non-temporary symbols");
294 AddSuffix = true;
295 }
296 llvm_unreachable("Infinite loop");
297}
298
299MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
300 SmallString<128> NameSV;
301 raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
302 return createSymbol(Name: NameSV, AlwaysAddSuffix, CanBeUnnamed: true);
303}
304
305MCSymbol *MCContext::createNamedTempSymbol(const Twine &Name) {
306 SmallString<128> NameSV;
307 raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
308 return createSymbol(Name: NameSV, AlwaysAddSuffix: true, CanBeUnnamed: false);
309}
310
311MCSymbol *MCContext::createLinkerPrivateTempSymbol() {
312 return createLinkerPrivateSymbol(Name: "tmp");
313}
314
315MCSymbol *MCContext::createLinkerPrivateSymbol(const Twine &Name) {
316 SmallString<128> NameSV;
317 raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << Name;
318 return createSymbol(Name: NameSV, AlwaysAddSuffix: true, CanBeUnnamed: false);
319}
320
321MCSymbol *MCContext::createTempSymbol() { return createTempSymbol(Name: "tmp"); }
322
323MCSymbol *MCContext::createNamedTempSymbol() {
324 return createNamedTempSymbol(Name: "tmp");
325}
326
327unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
328 MCLabel *&Label = Instances[LocalLabelVal];
329 if (!Label)
330 Label = new (*this) MCLabel(0);
331 return Label->incInstance();
332}
333
334unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
335 MCLabel *&Label = Instances[LocalLabelVal];
336 if (!Label)
337 Label = new (*this) MCLabel(0);
338 return Label->getInstance();
339}
340
341MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
342 unsigned Instance) {
343 MCSymbol *&Sym = LocalSymbols[std::make_pair(x&: LocalLabelVal, y&: Instance)];
344 if (!Sym)
345 Sym = createNamedTempSymbol();
346 return Sym;
347}
348
349MCSymbol *MCContext::createDirectionalLocalSymbol(unsigned LocalLabelVal) {
350 unsigned Instance = NextInstance(LocalLabelVal);
351 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
352}
353
354MCSymbol *MCContext::getDirectionalLocalSymbol(unsigned LocalLabelVal,
355 bool Before) {
356 unsigned Instance = GetInstance(LocalLabelVal);
357 if (!Before)
358 ++Instance;
359 return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
360}
361
362MCSymbol *MCContext::lookupSymbol(const Twine &Name) const {
363 SmallString<128> NameSV;
364 StringRef NameRef = Name.toStringRef(Out&: NameSV);
365 return Symbols.lookup(Key: NameRef);
366}
367
368void MCContext::setSymbolValue(MCStreamer &Streamer, const Twine &Sym,
369 uint64_t Val) {
370 auto Symbol = getOrCreateSymbol(Name: Sym);
371 Streamer.emitAssignment(Symbol, Value: MCConstantExpr::create(Value: Val, Ctx&: *this));
372}
373
374void MCContext::registerInlineAsmLabel(MCSymbol *Sym) {
375 InlineAsmUsedLabelNames[Sym->getName()] = Sym;
376}
377
378MCSymbolXCOFF *
379MCContext::createXCOFFSymbolImpl(const StringMapEntry<bool> *Name,
380 bool IsTemporary) {
381 if (!Name)
382 return new (nullptr, *this) MCSymbolXCOFF(nullptr, IsTemporary);
383
384 StringRef OriginalName = Name->first();
385 if (OriginalName.starts_with(Prefix: "._Renamed..") ||
386 OriginalName.starts_with(Prefix: "_Renamed.."))
387 reportError(L: SMLoc(), Msg: "invalid symbol name from source");
388
389 if (MAI->isValidUnquotedName(Name: OriginalName))
390 return new (Name, *this) MCSymbolXCOFF(Name, IsTemporary);
391
392 // Now we have a name that contains invalid character(s) for XCOFF symbol.
393 // Let's replace with something valid, but save the original name so that
394 // we could still use the original name in the symbol table.
395 SmallString<128> InvalidName(OriginalName);
396
397 // If it's an entry point symbol, we will keep the '.'
398 // in front for the convention purpose. Otherwise, add "_Renamed.."
399 // as prefix to signal this is an renamed symbol.
400 const bool IsEntryPoint = InvalidName.starts_with(Prefix: ".");
401 SmallString<128> ValidName =
402 StringRef(IsEntryPoint ? "._Renamed.." : "_Renamed..");
403
404 // Append the hex values of '_' and invalid characters with "_Renamed..";
405 // at the same time replace invalid characters with '_'.
406 for (size_t I = 0; I < InvalidName.size(); ++I) {
407 if (!MAI->isAcceptableChar(C: InvalidName[I]) || InvalidName[I] == '_') {
408 raw_svector_ostream(ValidName).write_hex(N: InvalidName[I]);
409 InvalidName[I] = '_';
410 }
411 }
412
413 // Skip entry point symbol's '.' as we already have a '.' in front of
414 // "_Renamed".
415 if (IsEntryPoint)
416 ValidName.append(RHS: InvalidName.substr(Start: 1, N: InvalidName.size() - 1));
417 else
418 ValidName.append(RHS: InvalidName);
419
420 auto NameEntry = UsedNames.insert(KV: std::make_pair(x: ValidName.str(), y: true));
421 assert((NameEntry.second || !NameEntry.first->second) &&
422 "This name is used somewhere else.");
423 // Mark the name as used for a non-section symbol.
424 NameEntry.first->second = true;
425 // Have the MCSymbol object itself refer to the copy of the string
426 // that is embedded in the UsedNames entry.
427 MCSymbolXCOFF *XSym = new (&*NameEntry.first, *this)
428 MCSymbolXCOFF(&*NameEntry.first, IsTemporary);
429 XSym->setSymbolTableName(MCSymbolXCOFF::getUnqualifiedName(Name: OriginalName));
430 return XSym;
431}
432
433//===----------------------------------------------------------------------===//
434// Section Management
435//===----------------------------------------------------------------------===//
436
437MCSectionMachO *MCContext::getMachOSection(StringRef Segment, StringRef Section,
438 unsigned TypeAndAttributes,
439 unsigned Reserved2, SectionKind Kind,
440 const char *BeginSymName) {
441 // We unique sections by their segment/section pair. The returned section
442 // may not have the same flags as the requested section, if so this should be
443 // diagnosed by the client as an error.
444
445 // Form the name to look up.
446 assert(Section.size() <= 16 && "section name is too long");
447 assert(!memchr(Section.data(), '\0', Section.size()) &&
448 "section name cannot contain NUL");
449
450 // Do the lookup, if we have a hit, return it.
451 auto R = MachOUniquingMap.try_emplace(Key: (Segment + Twine(',') + Section).str());
452 if (!R.second)
453 return R.first->second;
454
455 MCSymbol *Begin = nullptr;
456 if (BeginSymName)
457 Begin = createTempSymbol(Name: BeginSymName, AlwaysAddSuffix: false);
458
459 // Otherwise, return a new section.
460 StringRef Name = R.first->first();
461 R.first->second = new (MachOAllocator.Allocate())
462 MCSectionMachO(Segment, Name.substr(Start: Name.size() - Section.size()),
463 TypeAndAttributes, Reserved2, Kind, Begin);
464 return R.first->second;
465}
466
467MCSectionELF *MCContext::createELFSectionImpl(StringRef Section, unsigned Type,
468 unsigned Flags, SectionKind K,
469 unsigned EntrySize,
470 const MCSymbolELF *Group,
471 bool Comdat, unsigned UniqueID,
472 const MCSymbolELF *LinkedToSym) {
473 MCSymbolELF *R;
474 MCSymbol *&Sym = Symbols[Section];
475 // A section symbol can not redefine regular symbols. There may be multiple
476 // sections with the same name, in which case the first such section wins.
477 if (Sym && Sym->isDefined() &&
478 (!Sym->isInSection() || Sym->getSection().getBeginSymbol() != Sym))
479 reportError(L: SMLoc(), Msg: "invalid symbol redefinition");
480 if (Sym && Sym->isUndefined()) {
481 R = cast<MCSymbolELF>(Val: Sym);
482 } else {
483 auto NameIter = UsedNames.insert(KV: std::make_pair(x&: Section, y: false)).first;
484 R = new (&*NameIter, *this) MCSymbolELF(&*NameIter, /*isTemporary*/ false);
485 if (!Sym)
486 Sym = R;
487 }
488 R->setBinding(ELF::STB_LOCAL);
489 R->setType(ELF::STT_SECTION);
490
491 auto *Ret = new (ELFAllocator.Allocate())
492 MCSectionELF(Section, Type, Flags, K, EntrySize, Group, Comdat, UniqueID,
493 R, LinkedToSym);
494
495 auto *F = new MCDataFragment();
496 Ret->getFragmentList().insert(where: Ret->begin(), New: F);
497 F->setParent(Ret);
498 R->setFragment(F);
499
500 return Ret;
501}
502
503MCSectionELF *
504MCContext::createELFRelSection(const Twine &Name, unsigned Type, unsigned Flags,
505 unsigned EntrySize, const MCSymbolELF *Group,
506 const MCSectionELF *RelInfoSection) {
507 StringMap<bool>::iterator I;
508 bool Inserted;
509 std::tie(args&: I, args&: Inserted) = RelSecNames.insert(KV: std::make_pair(x: Name.str(), y: true));
510
511 return createELFSectionImpl(
512 Section: I->getKey(), Type, Flags, K: SectionKind::getReadOnly(), EntrySize, Group,
513 Comdat: true, UniqueID: true, LinkedToSym: cast<MCSymbolELF>(Val: RelInfoSection->getBeginSymbol()));
514}
515
516MCSectionELF *MCContext::getELFNamedSection(const Twine &Prefix,
517 const Twine &Suffix, unsigned Type,
518 unsigned Flags,
519 unsigned EntrySize) {
520 return getELFSection(Section: Prefix + "." + Suffix, Type, Flags, EntrySize, Group: Suffix,
521 /*IsComdat=*/true);
522}
523
524MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
525 unsigned Flags, unsigned EntrySize,
526 const Twine &Group, bool IsComdat,
527 unsigned UniqueID,
528 const MCSymbolELF *LinkedToSym) {
529 MCSymbolELF *GroupSym = nullptr;
530 if (!Group.isTriviallyEmpty() && !Group.str().empty())
531 GroupSym = cast<MCSymbolELF>(Val: getOrCreateSymbol(Name: Group));
532
533 return getELFSection(Section, Type, Flags, EntrySize, Group: GroupSym, IsComdat,
534 UniqueID, LinkedToSym);
535}
536
537MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
538 unsigned Flags, unsigned EntrySize,
539 const MCSymbolELF *GroupSym,
540 bool IsComdat, unsigned UniqueID,
541 const MCSymbolELF *LinkedToSym) {
542 StringRef Group = "";
543 if (GroupSym)
544 Group = GroupSym->getName();
545 assert(!(LinkedToSym && LinkedToSym->getName().empty()));
546 // Do the lookup, if we have a hit, return it.
547 auto IterBool = ELFUniquingMap.insert(x: std::make_pair(
548 x: ELFSectionKey{Section.str(), Group,
549 LinkedToSym ? LinkedToSym->getName() : "", UniqueID},
550 y: nullptr));
551 auto &Entry = *IterBool.first;
552 if (!IterBool.second)
553 return Entry.second;
554
555 StringRef CachedName = Entry.first.SectionName;
556
557 SectionKind Kind;
558 if (Flags & ELF::SHF_ARM_PURECODE)
559 Kind = SectionKind::getExecuteOnly();
560 else if (Flags & ELF::SHF_EXECINSTR)
561 Kind = SectionKind::getText();
562 else if (~Flags & ELF::SHF_WRITE)
563 Kind = SectionKind::getReadOnly();
564 else if (Flags & ELF::SHF_TLS)
565 Kind = (Type & ELF::SHT_NOBITS) ? SectionKind::getThreadBSS()
566 : SectionKind::getThreadData();
567 else
568 // Default to `SectionKind::getText()`. This is the default for gas as
569 // well. The condition that falls into this case is where we do not have any
570 // section flags and must infer a classification rather than where we have
571 // section flags (i.e. this is not that SHF_EXECINSTR is unset bur rather it
572 // is unknown).
573 Kind = llvm::StringSwitch<SectionKind>(CachedName)
574 .Case(S: ".bss", Value: SectionKind::getBSS())
575 .StartsWith(S: ".bss.", Value: SectionKind::getBSS())
576 .StartsWith(S: ".gnu.linkonce.b.", Value: SectionKind::getBSS())
577 .StartsWith(S: ".llvm.linkonce.b.", Value: SectionKind::getBSS())
578 .Case(S: ".data", Value: SectionKind::getData())
579 .Case(S: ".data1", Value: SectionKind::getData())
580 .Case(S: ".data.rel.ro", Value: SectionKind::getReadOnlyWithRel())
581 .StartsWith(S: ".data.", Value: SectionKind::getData())
582 .Case(S: ".rodata", Value: SectionKind::getReadOnly())
583 .Case(S: ".rodata1", Value: SectionKind::getReadOnly())
584 .StartsWith(S: ".rodata.", Value: SectionKind::getReadOnly())
585 .Case(S: ".tbss", Value: SectionKind::getThreadBSS())
586 .StartsWith(S: ".tbss.", Value: SectionKind::getThreadData())
587 .StartsWith(S: ".gnu.linkonce.tb.", Value: SectionKind::getThreadData())
588 .StartsWith(S: ".llvm.linkonce.tb.", Value: SectionKind::getThreadData())
589 .Case(S: ".tdata", Value: SectionKind::getThreadData())
590 .StartsWith(S: ".tdata.", Value: SectionKind::getThreadData())
591 .StartsWith(S: ".gnu.linkonce.td.", Value: SectionKind::getThreadData())
592 .StartsWith(S: ".llvm.linkonce.td.", Value: SectionKind::getThreadData())
593 .StartsWith(S: ".debug_", Value: SectionKind::getMetadata())
594 .Default(Value: SectionKind::getReadOnly());
595
596 MCSectionELF *Result =
597 createELFSectionImpl(Section: CachedName, Type, Flags, K: Kind, EntrySize, Group: GroupSym,
598 Comdat: IsComdat, UniqueID, LinkedToSym);
599 Entry.second = Result;
600
601 recordELFMergeableSectionInfo(SectionName: Result->getName(), Flags: Result->getFlags(),
602 UniqueID: Result->getUniqueID(), EntrySize: Result->getEntrySize());
603
604 return Result;
605}
606
607MCSectionELF *MCContext::createELFGroupSection(const MCSymbolELF *Group,
608 bool IsComdat) {
609 return createELFSectionImpl(Section: ".group", Type: ELF::SHT_GROUP, Flags: 0,
610 K: SectionKind::getReadOnly(), EntrySize: 4, Group, Comdat: IsComdat,
611 UniqueID: MCSection::NonUniqueID, LinkedToSym: nullptr);
612}
613
614void MCContext::recordELFMergeableSectionInfo(StringRef SectionName,
615 unsigned Flags, unsigned UniqueID,
616 unsigned EntrySize) {
617 bool IsMergeable = Flags & ELF::SHF_MERGE;
618 if (UniqueID == GenericSectionID)
619 ELFSeenGenericMergeableSections.insert(V: SectionName);
620
621 // For mergeable sections or non-mergeable sections with a generic mergeable
622 // section name we enter their Unique ID into the ELFEntrySizeMap so that
623 // compatible globals can be assigned to the same section.
624 if (IsMergeable || isELFGenericMergeableSection(Name: SectionName)) {
625 ELFEntrySizeMap.insert(x: std::make_pair(
626 x: ELFEntrySizeKey{SectionName, Flags, EntrySize}, y&: UniqueID));
627 }
628}
629
630bool MCContext::isELFImplicitMergeableSectionNamePrefix(StringRef SectionName) {
631 return SectionName.starts_with(Prefix: ".rodata.str") ||
632 SectionName.starts_with(Prefix: ".rodata.cst");
633}
634
635bool MCContext::isELFGenericMergeableSection(StringRef SectionName) {
636 return isELFImplicitMergeableSectionNamePrefix(SectionName) ||
637 ELFSeenGenericMergeableSections.count(V: SectionName);
638}
639
640std::optional<unsigned>
641MCContext::getELFUniqueIDForEntsize(StringRef SectionName, unsigned Flags,
642 unsigned EntrySize) {
643 auto I = ELFEntrySizeMap.find(
644 x: MCContext::ELFEntrySizeKey{SectionName, Flags, EntrySize});
645 return (I != ELFEntrySizeMap.end()) ? std::optional<unsigned>(I->second)
646 : std::nullopt;
647}
648
649MCSectionGOFF *MCContext::getGOFFSection(StringRef Section, SectionKind Kind,
650 MCSection *Parent,
651 const MCExpr *SubsectionId) {
652 // Do the lookup. If we don't have a hit, return a new section.
653 auto IterBool =
654 GOFFUniquingMap.insert(x: std::make_pair(x: Section.str(), y: nullptr));
655 auto Iter = IterBool.first;
656 if (!IterBool.second)
657 return Iter->second;
658
659 StringRef CachedName = Iter->first;
660 MCSectionGOFF *GOFFSection = new (GOFFAllocator.Allocate())
661 MCSectionGOFF(CachedName, Kind, Parent, SubsectionId);
662 Iter->second = GOFFSection;
663
664 return GOFFSection;
665}
666
667MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
668 unsigned Characteristics,
669 SectionKind Kind,
670 StringRef COMDATSymName, int Selection,
671 unsigned UniqueID,
672 const char *BeginSymName) {
673 MCSymbol *COMDATSymbol = nullptr;
674 if (!COMDATSymName.empty()) {
675 COMDATSymbol = getOrCreateSymbol(Name: COMDATSymName);
676 COMDATSymName = COMDATSymbol->getName();
677 }
678
679 // Do the lookup, if we have a hit, return it.
680 COFFSectionKey T{Section, COMDATSymName, Selection, UniqueID};
681 auto IterBool = COFFUniquingMap.insert(x: std::make_pair(x&: T, y: nullptr));
682 auto Iter = IterBool.first;
683 if (!IterBool.second)
684 return Iter->second;
685
686 MCSymbol *Begin = nullptr;
687 if (BeginSymName)
688 Begin = createTempSymbol(Name: BeginSymName, AlwaysAddSuffix: false);
689
690 StringRef CachedName = Iter->first.SectionName;
691 MCSectionCOFF *Result = new (COFFAllocator.Allocate()) MCSectionCOFF(
692 CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
693
694 Iter->second = Result;
695 return Result;
696}
697
698MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
699 unsigned Characteristics,
700 SectionKind Kind,
701 const char *BeginSymName) {
702 return getCOFFSection(Section, Characteristics, Kind, COMDATSymName: "", Selection: 0, UniqueID: GenericSectionID,
703 BeginSymName);
704}
705
706MCSectionCOFF *MCContext::getAssociativeCOFFSection(MCSectionCOFF *Sec,
707 const MCSymbol *KeySym,
708 unsigned UniqueID) {
709 // Return the normal section if we don't have to be associative or unique.
710 if (!KeySym && UniqueID == GenericSectionID)
711 return Sec;
712
713 // If we have a key symbol, make an associative section with the same name and
714 // kind as the normal section.
715 unsigned Characteristics = Sec->getCharacteristics();
716 if (KeySym) {
717 Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
718 return getCOFFSection(Section: Sec->getName(), Characteristics, Kind: Sec->getKind(),
719 COMDATSymName: KeySym->getName(),
720 Selection: COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID);
721 }
722
723 return getCOFFSection(Section: Sec->getName(), Characteristics, Kind: Sec->getKind(), COMDATSymName: "", Selection: 0,
724 UniqueID);
725}
726
727MCSectionWasm *MCContext::getWasmSection(const Twine &Section, SectionKind K,
728 unsigned Flags, const Twine &Group,
729 unsigned UniqueID,
730 const char *BeginSymName) {
731 MCSymbolWasm *GroupSym = nullptr;
732 if (!Group.isTriviallyEmpty() && !Group.str().empty()) {
733 GroupSym = cast<MCSymbolWasm>(Val: getOrCreateSymbol(Name: Group));
734 GroupSym->setComdat(true);
735 }
736
737 return getWasmSection(Section, K, Flags, Group: GroupSym, UniqueID, BeginSymName);
738}
739
740MCSectionWasm *MCContext::getWasmSection(const Twine &Section, SectionKind Kind,
741 unsigned Flags,
742 const MCSymbolWasm *GroupSym,
743 unsigned UniqueID,
744 const char *BeginSymName) {
745 StringRef Group = "";
746 if (GroupSym)
747 Group = GroupSym->getName();
748 // Do the lookup, if we have a hit, return it.
749 auto IterBool = WasmUniquingMap.insert(
750 x: std::make_pair(x: WasmSectionKey{Section.str(), Group, UniqueID}, y: nullptr));
751 auto &Entry = *IterBool.first;
752 if (!IterBool.second)
753 return Entry.second;
754
755 StringRef CachedName = Entry.first.SectionName;
756
757 MCSymbol *Begin = createSymbol(Name: CachedName, AlwaysAddSuffix: true, CanBeUnnamed: false);
758 Symbols[Begin->getName()] = Begin;
759 cast<MCSymbolWasm>(Val: Begin)->setType(wasm::WASM_SYMBOL_TYPE_SECTION);
760
761 MCSectionWasm *Result = new (WasmAllocator.Allocate())
762 MCSectionWasm(CachedName, Kind, Flags, GroupSym, UniqueID, Begin);
763 Entry.second = Result;
764
765 auto *F = new MCDataFragment();
766 Result->getFragmentList().insert(where: Result->begin(), New: F);
767 F->setParent(Result);
768 Begin->setFragment(F);
769
770 return Result;
771}
772
773bool MCContext::hasXCOFFSection(StringRef Section,
774 XCOFF::CsectProperties CsectProp) const {
775 return XCOFFUniquingMap.count(
776 x: XCOFFSectionKey(Section.str(), CsectProp.MappingClass)) != 0;
777}
778
779MCSectionXCOFF *MCContext::getXCOFFSection(
780 StringRef Section, SectionKind Kind,
781 std::optional<XCOFF::CsectProperties> CsectProp, bool MultiSymbolsAllowed,
782 const char *BeginSymName,
783 std::optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSectionSubtypeFlags) {
784 bool IsDwarfSec = DwarfSectionSubtypeFlags.has_value();
785 assert((IsDwarfSec != CsectProp.has_value()) && "Invalid XCOFF section!");
786
787 // Do the lookup. If we have a hit, return it.
788 auto IterBool = XCOFFUniquingMap.insert(x: std::make_pair(
789 x: IsDwarfSec ? XCOFFSectionKey(Section.str(), *DwarfSectionSubtypeFlags)
790 : XCOFFSectionKey(Section.str(), CsectProp->MappingClass),
791 y: nullptr));
792 auto &Entry = *IterBool.first;
793 if (!IterBool.second) {
794 MCSectionXCOFF *ExistedEntry = Entry.second;
795 if (ExistedEntry->isMultiSymbolsAllowed() != MultiSymbolsAllowed)
796 report_fatal_error(reason: "section's multiply symbols policy does not match");
797
798 return ExistedEntry;
799 }
800
801 // Otherwise, return a new section.
802 StringRef CachedName = Entry.first.SectionName;
803 MCSymbolXCOFF *QualName = nullptr;
804 // Debug section don't have storage class attribute.
805 if (IsDwarfSec)
806 QualName = cast<MCSymbolXCOFF>(Val: getOrCreateSymbol(Name: CachedName));
807 else
808 QualName = cast<MCSymbolXCOFF>(Val: getOrCreateSymbol(
809 Name: CachedName + "[" +
810 XCOFF::getMappingClassString(SMC: CsectProp->MappingClass) + "]"));
811
812 MCSymbol *Begin = nullptr;
813 if (BeginSymName)
814 Begin = createTempSymbol(Name: BeginSymName, AlwaysAddSuffix: false);
815
816 // QualName->getUnqualifiedName() and CachedName are the same except when
817 // CachedName contains invalid character(s) such as '$' for an XCOFF symbol.
818 MCSectionXCOFF *Result = nullptr;
819 if (IsDwarfSec)
820 Result = new (XCOFFAllocator.Allocate()) MCSectionXCOFF(
821 QualName->getUnqualifiedName(), Kind, QualName,
822 *DwarfSectionSubtypeFlags, Begin, CachedName, MultiSymbolsAllowed);
823 else
824 Result = new (XCOFFAllocator.Allocate())
825 MCSectionXCOFF(QualName->getUnqualifiedName(), CsectProp->MappingClass,
826 CsectProp->Type, Kind, QualName, Begin, CachedName,
827 MultiSymbolsAllowed);
828
829 Entry.second = Result;
830
831 auto *F = new MCDataFragment();
832 Result->getFragmentList().insert(where: Result->begin(), New: F);
833 F->setParent(Result);
834
835 if (Begin)
836 Begin->setFragment(F);
837
838 // We might miss calculating the symbols difference as absolute value before
839 // adding fixups when symbol_A without the fragment set is the csect itself
840 // and symbol_B is in it.
841 // TODO: Currently we only set the fragment for XMC_PR csects because we don't
842 // have other cases that hit this problem yet.
843 if (!IsDwarfSec && CsectProp->MappingClass == XCOFF::XMC_PR)
844 QualName->setFragment(F);
845
846 return Result;
847}
848
849MCSectionSPIRV *MCContext::getSPIRVSection() {
850 MCSymbol *Begin = nullptr;
851 MCSectionSPIRV *Result = new (SPIRVAllocator.Allocate())
852 MCSectionSPIRV(SectionKind::getText(), Begin);
853
854 auto *F = new MCDataFragment();
855 Result->getFragmentList().insert(where: Result->begin(), New: F);
856 F->setParent(Result);
857
858 return Result;
859}
860
861MCSectionDXContainer *MCContext::getDXContainerSection(StringRef Section,
862 SectionKind K) {
863 // Do the lookup, if we have a hit, return it.
864 auto ItInsertedPair = DXCUniquingMap.try_emplace(Key: Section);
865 if (!ItInsertedPair.second)
866 return ItInsertedPair.first->second;
867
868 auto MapIt = ItInsertedPair.first;
869 // Grab the name from the StringMap. Since the Section is going to keep a
870 // copy of this StringRef we need to make sure the underlying string stays
871 // alive as long as we need it.
872 StringRef Name = MapIt->first();
873 MapIt->second =
874 new (DXCAllocator.Allocate()) MCSectionDXContainer(Name, K, nullptr);
875
876 // The first fragment will store the header
877 auto *F = new MCDataFragment();
878 MapIt->second->getFragmentList().insert(where: MapIt->second->begin(), New: F);
879 F->setParent(MapIt->second);
880
881 return MapIt->second;
882}
883
884MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
885 return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
886}
887
888void MCContext::addDebugPrefixMapEntry(const std::string &From,
889 const std::string &To) {
890 DebugPrefixMap.emplace_back(Args: From, Args: To);
891}
892
893void MCContext::remapDebugPath(SmallVectorImpl<char> &Path) {
894 for (const auto &[From, To] : llvm::reverse(C&: DebugPrefixMap))
895 if (llvm::sys::path::replace_path_prefix(Path, OldPrefix: From, NewPrefix: To))
896 break;
897}
898
899void MCContext::RemapDebugPaths() {
900 const auto &DebugPrefixMap = this->DebugPrefixMap;
901 if (DebugPrefixMap.empty())
902 return;
903
904 // Remap compilation directory.
905 remapDebugPath(Path&: CompilationDir);
906
907 // Remap MCDwarfDirs and RootFile.Name in all compilation units.
908 SmallString<256> P;
909 for (auto &CUIDTablePair : MCDwarfLineTablesCUMap) {
910 for (auto &Dir : CUIDTablePair.second.getMCDwarfDirs()) {
911 P = Dir;
912 remapDebugPath(Path&: P);
913 Dir = std::string(P);
914 }
915
916 // Used by DW_TAG_compile_unit's DT_AT_name and DW_TAG_label's
917 // DW_AT_decl_file for DWARF v5 generated for assembly source.
918 P = CUIDTablePair.second.getRootFile().Name;
919 remapDebugPath(Path&: P);
920 CUIDTablePair.second.getRootFile().Name = std::string(P);
921 }
922}
923
924//===----------------------------------------------------------------------===//
925// Dwarf Management
926//===----------------------------------------------------------------------===//
927
928EmitDwarfUnwindType MCContext::emitDwarfUnwindInfo() const {
929 if (!TargetOptions)
930 return EmitDwarfUnwindType::Default;
931 return TargetOptions->EmitDwarfUnwind;
932}
933
934bool MCContext::emitCompactUnwindNonCanonical() const {
935 if (TargetOptions)
936 return TargetOptions->EmitCompactUnwindNonCanonical;
937 return false;
938}
939
940void MCContext::setGenDwarfRootFile(StringRef InputFileName, StringRef Buffer) {
941 // MCDwarf needs the root file as well as the compilation directory.
942 // If we find a '.file 0' directive that will supersede these values.
943 std::optional<MD5::MD5Result> Cksum;
944 if (getDwarfVersion() >= 5) {
945 MD5 Hash;
946 MD5::MD5Result Sum;
947 Hash.update(Str: Buffer);
948 Hash.final(Result&: Sum);
949 Cksum = Sum;
950 }
951 // Canonicalize the root filename. It cannot be empty, and should not
952 // repeat the compilation dir.
953 // The MCContext ctor initializes MainFileName to the name associated with
954 // the SrcMgr's main file ID, which might be the same as InputFileName (and
955 // possibly include directory components).
956 // Or, MainFileName might have been overridden by a -main-file-name option,
957 // which is supposed to be just a base filename with no directory component.
958 // So, if the InputFileName and MainFileName are not equal, assume
959 // MainFileName is a substitute basename and replace the last component.
960 SmallString<1024> FileNameBuf = InputFileName;
961 if (FileNameBuf.empty() || FileNameBuf == "-")
962 FileNameBuf = "<stdin>";
963 if (!getMainFileName().empty() && FileNameBuf != getMainFileName()) {
964 llvm::sys::path::remove_filename(path&: FileNameBuf);
965 llvm::sys::path::append(path&: FileNameBuf, a: getMainFileName());
966 }
967 StringRef FileName = FileNameBuf;
968 if (FileName.consume_front(Prefix: getCompilationDir()))
969 if (llvm::sys::path::is_separator(value: FileName.front()))
970 FileName = FileName.drop_front();
971 assert(!FileName.empty());
972 setMCLineTableRootFile(
973 /*CUID=*/0, CompilationDir: getCompilationDir(), Filename: FileName, Checksum: Cksum, Source: std::nullopt);
974}
975
976/// getDwarfFile - takes a file name and number to place in the dwarf file and
977/// directory tables. If the file number has already been allocated it is an
978/// error and zero is returned and the client reports the error, else the
979/// allocated file number is returned. The file numbers may be in any order.
980Expected<unsigned>
981MCContext::getDwarfFile(StringRef Directory, StringRef FileName,
982 unsigned FileNumber,
983 std::optional<MD5::MD5Result> Checksum,
984 std::optional<StringRef> Source, unsigned CUID) {
985 MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
986 return Table.tryGetFile(Directory, FileName, Checksum, Source, DwarfVersion,
987 FileNumber);
988}
989
990/// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
991/// currently is assigned and false otherwise.
992bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
993 const MCDwarfLineTable &LineTable = getMCDwarfLineTable(CUID);
994 if (FileNumber == 0)
995 return getDwarfVersion() >= 5;
996 if (FileNumber >= LineTable.getMCDwarfFiles().size())
997 return false;
998
999 return !LineTable.getMCDwarfFiles()[FileNumber].Name.empty();
1000}
1001
1002/// Remove empty sections from SectionsForRanges, to avoid generating
1003/// useless debug info for them.
1004void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
1005 SectionsForRanges.remove_if(
1006 P: [&](MCSection *Sec) { return !MCOS.mayHaveInstructions(Sec&: *Sec); });
1007}
1008
1009CodeViewContext &MCContext::getCVContext() {
1010 if (!CVContext)
1011 CVContext.reset(p: new CodeViewContext);
1012 return *CVContext;
1013}
1014
1015//===----------------------------------------------------------------------===//
1016// Error Reporting
1017//===----------------------------------------------------------------------===//
1018
1019void MCContext::diagnose(const SMDiagnostic &SMD) {
1020 assert(DiagHandler && "MCContext::DiagHandler is not set");
1021 bool UseInlineSrcMgr = false;
1022 const SourceMgr *SMP = nullptr;
1023 if (SrcMgr) {
1024 SMP = SrcMgr;
1025 } else if (InlineSrcMgr) {
1026 SMP = InlineSrcMgr.get();
1027 UseInlineSrcMgr = true;
1028 } else
1029 llvm_unreachable("Either SourceMgr should be available");
1030 DiagHandler(SMD, UseInlineSrcMgr, *SMP, LocInfos);
1031}
1032
1033void MCContext::reportCommon(
1034 SMLoc Loc,
1035 std::function<void(SMDiagnostic &, const SourceMgr *)> GetMessage) {
1036 // * MCContext::SrcMgr is null when the MC layer emits machine code for input
1037 // other than assembly file, say, for .c/.cpp/.ll/.bc.
1038 // * MCContext::InlineSrcMgr is null when the inline asm is not used.
1039 // * A default SourceMgr is needed for diagnosing when both MCContext::SrcMgr
1040 // and MCContext::InlineSrcMgr are null.
1041 SourceMgr SM;
1042 const SourceMgr *SMP = &SM;
1043 bool UseInlineSrcMgr = false;
1044
1045 // FIXME: Simplify these by combining InlineSrcMgr & SrcMgr.
1046 // For MC-only execution, only SrcMgr is used;
1047 // For non MC-only execution, InlineSrcMgr is only ctor'd if there is
1048 // inline asm in the IR.
1049 if (Loc.isValid()) {
1050 if (SrcMgr) {
1051 SMP = SrcMgr;
1052 } else if (InlineSrcMgr) {
1053 SMP = InlineSrcMgr.get();
1054 UseInlineSrcMgr = true;
1055 } else
1056 llvm_unreachable("Either SourceMgr should be available");
1057 }
1058
1059 SMDiagnostic D;
1060 GetMessage(D, SMP);
1061 DiagHandler(D, UseInlineSrcMgr, *SMP, LocInfos);
1062}
1063
1064void MCContext::reportError(SMLoc Loc, const Twine &Msg) {
1065 HadError = true;
1066 reportCommon(Loc, GetMessage: [&](SMDiagnostic &D, const SourceMgr *SMP) {
1067 D = SMP->GetMessage(Loc, Kind: SourceMgr::DK_Error, Msg);
1068 });
1069}
1070
1071void MCContext::reportWarning(SMLoc Loc, const Twine &Msg) {
1072 if (TargetOptions && TargetOptions->MCNoWarn)
1073 return;
1074 if (TargetOptions && TargetOptions->MCFatalWarnings) {
1075 reportError(Loc, Msg);
1076 } else {
1077 reportCommon(Loc, GetMessage: [&](SMDiagnostic &D, const SourceMgr *SMP) {
1078 D = SMP->GetMessage(Loc, Kind: SourceMgr::DK_Warning, Msg);
1079 });
1080 }
1081}
1082

source code of llvm/lib/MC/MCContext.cpp