xref: /freebsd/contrib/llvm-project/llvm/lib/MC/MCStreamer.cpp (revision 02e9120893770924227138ba49df1edb3896112a) 
1 //===- lib/MC/MCStreamer.cpp - Streaming Machine Code Output --------------===//
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/MCStreamer.h"
10 #include "llvm/ADT/SmallString.h"
11 #include "llvm/ADT/StringRef.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/BinaryFormat/COFF.h"
14 #include "llvm/BinaryFormat/MachO.h"
15 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
16 #include "llvm/MC/MCAsmBackend.h"
17 #include "llvm/MC/MCAsmInfo.h"
18 #include "llvm/MC/MCCodeView.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCDwarf.h"
21 #include "llvm/MC/MCExpr.h"
22 #include "llvm/MC/MCInst.h"
23 #include "llvm/MC/MCInstPrinter.h"
24 #include "llvm/MC/MCObjectFileInfo.h"
25 #include "llvm/MC/MCPseudoProbe.h"
26 #include "llvm/MC/MCRegister.h"
27 #include "llvm/MC/MCRegisterInfo.h"
28 #include "llvm/MC/MCSection.h"
29 #include "llvm/MC/MCSectionCOFF.h"
30 #include "llvm/MC/MCSymbol.h"
31 #include "llvm/MC/MCWin64EH.h"
32 #include "llvm/MC/MCWinEH.h"
33 #include "llvm/Support/Casting.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/LEB128.h"
36 #include "llvm/Support/MathExtras.h"
37 #include "llvm/Support/raw_ostream.h"
38 #include <cassert>
39 #include <cstdint>
40 #include <cstdlib>
41 #include <optional>
42 #include <utility>
43 
44 using namespace llvm;
45 
46 MCTargetStreamer::MCTargetStreamer(MCStreamer &S) : Streamer(S) {
47   S.setTargetStreamer(this);
48 }
49 
50 // Pin the vtables to this file.
51 MCTargetStreamer::~MCTargetStreamer() = default;
52 
53 void MCTargetStreamer::emitLabel(MCSymbol *Symbol) {}
54 
55 void MCTargetStreamer::finish() {}
56 
57 void MCTargetStreamer::emitConstantPools() {}
58 
59 void MCTargetStreamer::changeSection(const MCSection *CurSection,
60                                      MCSection *Section,
61                                      const MCExpr *Subsection,
62                                      raw_ostream &OS) {
63   Section->printSwitchToSection(*Streamer.getContext().getAsmInfo(),
64                                 Streamer.getContext().getTargetTriple(), OS,
65                                 Subsection);
66 }
67 
68 void MCTargetStreamer::emitDwarfFileDirective(StringRef Directive) {
69   Streamer.emitRawText(Directive);
70 }
71 
72 void MCTargetStreamer::emitValue(const MCExpr *Value) {
73   SmallString<128> Str;
74   raw_svector_ostream OS(Str);
75 
76   Value->print(OS, Streamer.getContext().getAsmInfo());
77   Streamer.emitRawText(OS.str());
78 }
79 
80 void MCTargetStreamer::emitRawBytes(StringRef Data) {
81   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
82   const char *Directive = MAI->getData8bitsDirective();
83   for (const unsigned char C : Data.bytes()) {
84     SmallString<128> Str;
85     raw_svector_ostream OS(Str);
86 
87     OS << Directive << (unsigned)C;
88     Streamer.emitRawText(OS.str());
89   }
90 }
91 
92 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
93 
94 MCStreamer::MCStreamer(MCContext &Ctx)
95     : Context(Ctx), CurrentWinFrameInfo(nullptr),
96       CurrentProcWinFrameInfoStartIndex(0), UseAssemblerInfoForParsing(false) {
97   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
98 }
99 
100 MCStreamer::~MCStreamer() = default;
101 
102 void MCStreamer::reset() {
103   DwarfFrameInfos.clear();
104   CurrentWinFrameInfo = nullptr;
105   WinFrameInfos.clear();
106   SymbolOrdering.clear();
107   SectionStack.clear();
108   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
109 }
110 
111 raw_ostream &MCStreamer::getCommentOS() {
112   // By default, discard comments.
113   return nulls();
114 }
115 
116 unsigned MCStreamer::getNumFrameInfos() { return DwarfFrameInfos.size(); }
117 ArrayRef<MCDwarfFrameInfo> MCStreamer::getDwarfFrameInfos() const {
118   return DwarfFrameInfos;
119 }
120 
121 void MCStreamer::emitRawComment(const Twine &T, bool TabPrefix) {}
122 
123 void MCStreamer::addExplicitComment(const Twine &T) {}
124 void MCStreamer::emitExplicitComments() {}
125 
126 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
127   for (auto &FI : DwarfFrameInfos)
128     FI.CompactUnwindEncoding =
129         (MAB ? MAB->generateCompactUnwindEncoding(&FI, &Context) : 0);
130 }
131 
132 /// EmitIntValue - Special case of EmitValue that avoids the client having to
133 /// pass in a MCExpr for constant integers.
134 void MCStreamer::emitIntValue(uint64_t Value, unsigned Size) {
135   assert(1 <= Size && Size <= 8 && "Invalid size");
136   assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
137          "Invalid size");
138   const bool IsLittleEndian = Context.getAsmInfo()->isLittleEndian();
139   uint64_t Swapped = support::endian::byte_swap(
140       Value, IsLittleEndian ? support::little : support::big);
141   unsigned Index = IsLittleEndian ? 0 : 8 - Size;
142   emitBytes(StringRef(reinterpret_cast<char *>(&Swapped) + Index, Size));
143 }
144 void MCStreamer::emitIntValue(APInt Value) {
145   if (Value.getNumWords() == 1) {
146     emitIntValue(Value.getLimitedValue(), Value.getBitWidth() / 8);
147     return;
148   }
149 
150   const bool IsLittleEndianTarget = Context.getAsmInfo()->isLittleEndian();
151   const bool ShouldSwap = sys::IsLittleEndianHost != IsLittleEndianTarget;
152   const APInt Swapped = ShouldSwap ? Value.byteSwap() : Value;
153   const unsigned Size = Value.getBitWidth() / 8;
154   SmallString<10> Tmp;
155   Tmp.resize(Size);
156   StoreIntToMemory(Swapped, reinterpret_cast<uint8_t *>(Tmp.data()), Size);
157   emitBytes(Tmp.str());
158 }
159 
160 /// EmitULEB128IntValue - Special case of EmitULEB128Value that avoids the
161 /// client having to pass in a MCExpr for constant integers.
162 unsigned MCStreamer::emitULEB128IntValue(uint64_t Value, unsigned PadTo) {
163   SmallString<128> Tmp;
164   raw_svector_ostream OSE(Tmp);
165   encodeULEB128(Value, OSE, PadTo);
166   emitBytes(OSE.str());
167   return Tmp.size();
168 }
169 
170 /// EmitSLEB128IntValue - Special case of EmitSLEB128Value that avoids the
171 /// client having to pass in a MCExpr for constant integers.
172 unsigned MCStreamer::emitSLEB128IntValue(int64_t Value) {
173   SmallString<128> Tmp;
174   raw_svector_ostream OSE(Tmp);
175   encodeSLEB128(Value, OSE);
176   emitBytes(OSE.str());
177   return Tmp.size();
178 }
179 
180 void MCStreamer::emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc) {
181   emitValueImpl(Value, Size, Loc);
182 }
183 
184 void MCStreamer::emitSymbolValue(const MCSymbol *Sym, unsigned Size,
185                                  bool IsSectionRelative) {
186   assert((!IsSectionRelative || Size == 4) &&
187          "SectionRelative value requires 4-bytes");
188 
189   if (!IsSectionRelative)
190     emitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
191   else
192     emitCOFFSecRel32(Sym, /*Offset=*/0);
193 }
194 
195 void MCStreamer::emitDTPRel64Value(const MCExpr *Value) {
196   report_fatal_error("unsupported directive in streamer");
197 }
198 
199 void MCStreamer::emitDTPRel32Value(const MCExpr *Value) {
200   report_fatal_error("unsupported directive in streamer");
201 }
202 
203 void MCStreamer::emitTPRel64Value(const MCExpr *Value) {
204   report_fatal_error("unsupported directive in streamer");
205 }
206 
207 void MCStreamer::emitTPRel32Value(const MCExpr *Value) {
208   report_fatal_error("unsupported directive in streamer");
209 }
210 
211 void MCStreamer::emitGPRel64Value(const MCExpr *Value) {
212   report_fatal_error("unsupported directive in streamer");
213 }
214 
215 void MCStreamer::emitGPRel32Value(const MCExpr *Value) {
216   report_fatal_error("unsupported directive in streamer");
217 }
218 
219 /// Emit NumBytes bytes worth of the value specified by FillValue.
220 /// This implements directives such as '.space'.
221 void MCStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
222   if (NumBytes)
223     emitFill(*MCConstantExpr::create(NumBytes, getContext()), FillValue);
224 }
225 
226 void llvm::MCStreamer::emitNops(int64_t NumBytes, int64_t ControlledNopLen,
227                                 llvm::SMLoc, const MCSubtargetInfo& STI) {}
228 
229 /// The implementation in this class just redirects to emitFill.
230 void MCStreamer::emitZeros(uint64_t NumBytes) { emitFill(NumBytes, 0); }
231 
232 Expected<unsigned> MCStreamer::tryEmitDwarfFileDirective(
233     unsigned FileNo, StringRef Directory, StringRef Filename,
234     std::optional<MD5::MD5Result> Checksum, std::optional<StringRef> Source,
235     unsigned CUID) {
236   return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
237                                    Source, CUID);
238 }
239 
240 void MCStreamer::emitDwarfFile0Directive(StringRef Directory,
241                                          StringRef Filename,
242                                          std::optional<MD5::MD5Result> Checksum,
243                                          std::optional<StringRef> Source,
244                                          unsigned CUID) {
245   getContext().setMCLineTableRootFile(CUID, Directory, Filename, Checksum,
246                                       Source);
247 }
248 
249 void MCStreamer::emitCFIBKeyFrame() {
250   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
251   if (!CurFrame)
252     return;
253   CurFrame->IsBKeyFrame = true;
254 }
255 
256 void MCStreamer::emitCFIMTETaggedFrame() {
257   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
258   if (!CurFrame)
259     return;
260   CurFrame->IsMTETaggedFrame = true;
261 }
262 
263 void MCStreamer::emitDwarfLocDirective(unsigned FileNo, unsigned Line,
264                                        unsigned Column, unsigned Flags,
265                                        unsigned Isa, unsigned Discriminator,
266                                        StringRef FileName) {
267   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
268                                   Discriminator);
269 }
270 
271 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
272   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
273   if (!Table.getLabel()) {
274     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
275     Table.setLabel(
276         Context.getOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
277   }
278   return Table.getLabel();
279 }
280 
281 bool MCStreamer::hasUnfinishedDwarfFrameInfo() {
282   return !FrameInfoStack.empty();
283 }
284 
285 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
286   if (!hasUnfinishedDwarfFrameInfo()) {
287     getContext().reportError(getStartTokLoc(),
288                              "this directive must appear between "
289                              ".cfi_startproc and .cfi_endproc directives");
290     return nullptr;
291   }
292   return &DwarfFrameInfos[FrameInfoStack.back().first];
293 }
294 
295 bool MCStreamer::emitCVFileDirective(unsigned FileNo, StringRef Filename,
296                                      ArrayRef<uint8_t> Checksum,
297                                      unsigned ChecksumKind) {
298   return getContext().getCVContext().addFile(*this, FileNo, Filename, Checksum,
299                                              ChecksumKind);
300 }
301 
302 bool MCStreamer::emitCVFuncIdDirective(unsigned FunctionId) {
303   return getContext().getCVContext().recordFunctionId(FunctionId);
304 }
305 
306 bool MCStreamer::emitCVInlineSiteIdDirective(unsigned FunctionId,
307                                              unsigned IAFunc, unsigned IAFile,
308                                              unsigned IALine, unsigned IACol,
309                                              SMLoc Loc) {
310   if (getContext().getCVContext().getCVFunctionInfo(IAFunc) == nullptr) {
311     getContext().reportError(Loc, "parent function id not introduced by "
312                                   ".cv_func_id or .cv_inline_site_id");
313     return true;
314   }
315 
316   return getContext().getCVContext().recordInlinedCallSiteId(
317       FunctionId, IAFunc, IAFile, IALine, IACol);
318 }
319 
320 void MCStreamer::emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
321                                     unsigned Line, unsigned Column,
322                                     bool PrologueEnd, bool IsStmt,
323                                     StringRef FileName, SMLoc Loc) {}
324 
325 bool MCStreamer::checkCVLocSection(unsigned FuncId, unsigned FileNo,
326                                    SMLoc Loc) {
327   CodeViewContext &CVC = getContext().getCVContext();
328   MCCVFunctionInfo *FI = CVC.getCVFunctionInfo(FuncId);
329   if (!FI) {
330     getContext().reportError(
331         Loc, "function id not introduced by .cv_func_id or .cv_inline_site_id");
332     return false;
333   }
334 
335   // Track the section
336   if (FI->Section == nullptr)
337     FI->Section = getCurrentSectionOnly();
338   else if (FI->Section != getCurrentSectionOnly()) {
339     getContext().reportError(
340         Loc,
341         "all .cv_loc directives for a function must be in the same section");
342     return false;
343   }
344   return true;
345 }
346 
347 void MCStreamer::emitCVLinetableDirective(unsigned FunctionId,
348                                           const MCSymbol *Begin,
349                                           const MCSymbol *End) {}
350 
351 void MCStreamer::emitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
352                                                 unsigned SourceFileId,
353                                                 unsigned SourceLineNum,
354                                                 const MCSymbol *FnStartSym,
355                                                 const MCSymbol *FnEndSym) {}
356 
357 /// Only call this on endian-specific types like ulittle16_t and little32_t, or
358 /// structs composed of them.
359 template <typename T>
360 static void copyBytesForDefRange(SmallString<20> &BytePrefix,
361                                  codeview::SymbolKind SymKind,
362                                  const T &DefRangeHeader) {
363   BytePrefix.resize(2 + sizeof(T));
364   codeview::ulittle16_t SymKindLE = codeview::ulittle16_t(SymKind);
365   memcpy(&BytePrefix[0], &SymKindLE, 2);
366   memcpy(&BytePrefix[2], &DefRangeHeader, sizeof(T));
367 }
368 
369 void MCStreamer::emitCVDefRangeDirective(
370     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
371     StringRef FixedSizePortion) {}
372 
373 void MCStreamer::emitCVDefRangeDirective(
374     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
375     codeview::DefRangeRegisterRelHeader DRHdr) {
376   SmallString<20> BytePrefix;
377   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER_REL, DRHdr);
378   emitCVDefRangeDirective(Ranges, BytePrefix);
379 }
380 
381 void MCStreamer::emitCVDefRangeDirective(
382     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
383     codeview::DefRangeSubfieldRegisterHeader DRHdr) {
384   SmallString<20> BytePrefix;
385   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_SUBFIELD_REGISTER,
386                        DRHdr);
387   emitCVDefRangeDirective(Ranges, BytePrefix);
388 }
389 
390 void MCStreamer::emitCVDefRangeDirective(
391     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
392     codeview::DefRangeRegisterHeader DRHdr) {
393   SmallString<20> BytePrefix;
394   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER, DRHdr);
395   emitCVDefRangeDirective(Ranges, BytePrefix);
396 }
397 
398 void MCStreamer::emitCVDefRangeDirective(
399     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
400     codeview::DefRangeFramePointerRelHeader DRHdr) {
401   SmallString<20> BytePrefix;
402   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_FRAMEPOINTER_REL,
403                        DRHdr);
404   emitCVDefRangeDirective(Ranges, BytePrefix);
405 }
406 
407 void MCStreamer::emitEHSymAttributes(const MCSymbol *Symbol,
408                                      MCSymbol *EHSymbol) {
409 }
410 
411 void MCStreamer::initSections(bool NoExecStack, const MCSubtargetInfo &STI) {
412   switchSection(getContext().getObjectFileInfo()->getTextSection());
413 }
414 
415 void MCStreamer::assignFragment(MCSymbol *Symbol, MCFragment *Fragment) {
416   assert(Fragment);
417   Symbol->setFragment(Fragment);
418 
419   // As we emit symbols into a section, track the order so that they can
420   // be sorted upon later. Zero is reserved to mean 'unemitted'.
421   SymbolOrdering[Symbol] = 1 + SymbolOrdering.size();
422 }
423 
424 void MCStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
425   Symbol->redefineIfPossible();
426 
427   if (!Symbol->isUndefined() || Symbol->isVariable())
428     return getContext().reportError(Loc, "symbol '" + Twine(Symbol->getName()) +
429                                              "' is already defined");
430 
431   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
432   assert(getCurrentSectionOnly() && "Cannot emit before setting section!");
433   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
434   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
435 
436   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());
437 
438   MCTargetStreamer *TS = getTargetStreamer();
439   if (TS)
440     TS->emitLabel(Symbol);
441 }
442 
443 void MCStreamer::emitConditionalAssignment(MCSymbol *Symbol,
444                                            const MCExpr *Value) {}
445 
446 void MCStreamer::emitCFISections(bool EH, bool Debug) {}
447 
448 void MCStreamer::emitCFIStartProc(bool IsSimple, SMLoc Loc) {
449   if (!FrameInfoStack.empty() &&
450       getCurrentSectionOnly() == FrameInfoStack.back().second)
451     return getContext().reportError(
452         Loc, "starting new .cfi frame before finishing the previous one");
453 
454   MCDwarfFrameInfo Frame;
455   Frame.IsSimple = IsSimple;
456   emitCFIStartProcImpl(Frame);
457 
458   const MCAsmInfo* MAI = Context.getAsmInfo();
459   if (MAI) {
460     for (const MCCFIInstruction& Inst : MAI->getInitialFrameState()) {
461       if (Inst.getOperation() == MCCFIInstruction::OpDefCfa ||
462           Inst.getOperation() == MCCFIInstruction::OpDefCfaRegister ||
463           Inst.getOperation() == MCCFIInstruction::OpLLVMDefAspaceCfa) {
464         Frame.CurrentCfaRegister = Inst.getRegister();
465       }
466     }
467   }
468 
469   FrameInfoStack.emplace_back(DwarfFrameInfos.size(), getCurrentSectionOnly());
470   DwarfFrameInfos.push_back(Frame);
471 }
472 
473 void MCStreamer::emitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
474 }
475 
476 void MCStreamer::emitCFIEndProc() {
477   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
478   if (!CurFrame)
479     return;
480   emitCFIEndProcImpl(*CurFrame);
481   FrameInfoStack.pop_back();
482 }
483 
484 void MCStreamer::emitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
485   // Put a dummy non-null value in Frame.End to mark that this frame has been
486   // closed.
487   Frame.End = (MCSymbol *)1;
488 }
489 
490 MCSymbol *MCStreamer::emitCFILabel() {
491   // Return a dummy non-null value so that label fields appear filled in when
492   // generating textual assembly.
493   return (MCSymbol *)1;
494 }
495 
496 void MCStreamer::emitCFIDefCfa(int64_t Register, int64_t Offset, SMLoc Loc) {
497   MCSymbol *Label = emitCFILabel();
498   MCCFIInstruction Instruction =
499       MCCFIInstruction::cfiDefCfa(Label, Register, Offset, Loc);
500   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
501   if (!CurFrame)
502     return;
503   CurFrame->Instructions.push_back(Instruction);
504   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
505 }
506 
507 void MCStreamer::emitCFIDefCfaOffset(int64_t Offset, SMLoc Loc) {
508   MCSymbol *Label = emitCFILabel();
509   MCCFIInstruction Instruction =
510       MCCFIInstruction::cfiDefCfaOffset(Label, Offset);
511   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
512   if (!CurFrame)
513     return;
514   CurFrame->Instructions.push_back(Instruction);
515 }
516 
517 void MCStreamer::emitCFIAdjustCfaOffset(int64_t Adjustment, SMLoc Loc) {
518   MCSymbol *Label = emitCFILabel();
519   MCCFIInstruction Instruction =
520       MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment, Loc);
521   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
522   if (!CurFrame)
523     return;
524   CurFrame->Instructions.push_back(Instruction);
525 }
526 
527 void MCStreamer::emitCFIDefCfaRegister(int64_t Register, SMLoc Loc) {
528   MCSymbol *Label = emitCFILabel();
529   MCCFIInstruction Instruction =
530       MCCFIInstruction::createDefCfaRegister(Label, Register, Loc);
531   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
532   if (!CurFrame)
533     return;
534   CurFrame->Instructions.push_back(Instruction);
535   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
536 }
537 
538 void MCStreamer::emitCFILLVMDefAspaceCfa(int64_t Register, int64_t Offset,
539                                          int64_t AddressSpace, SMLoc Loc) {
540   MCSymbol *Label = emitCFILabel();
541   MCCFIInstruction Instruction = MCCFIInstruction::createLLVMDefAspaceCfa(
542       Label, Register, Offset, AddressSpace, Loc);
543   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
544   if (!CurFrame)
545     return;
546   CurFrame->Instructions.push_back(Instruction);
547   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
548 }
549 
550 void MCStreamer::emitCFIOffset(int64_t Register, int64_t Offset, SMLoc Loc) {
551   MCSymbol *Label = emitCFILabel();
552   MCCFIInstruction Instruction =
553       MCCFIInstruction::createOffset(Label, Register, Offset, Loc);
554   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
555   if (!CurFrame)
556     return;
557   CurFrame->Instructions.push_back(Instruction);
558 }
559 
560 void MCStreamer::emitCFIRelOffset(int64_t Register, int64_t Offset, SMLoc Loc) {
561   MCSymbol *Label = emitCFILabel();
562   MCCFIInstruction Instruction =
563       MCCFIInstruction::createRelOffset(Label, Register, Offset, Loc);
564   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
565   if (!CurFrame)
566     return;
567   CurFrame->Instructions.push_back(Instruction);
568 }
569 
570 void MCStreamer::emitCFIPersonality(const MCSymbol *Sym,
571                                     unsigned Encoding) {
572   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
573   if (!CurFrame)
574     return;
575   CurFrame->Personality = Sym;
576   CurFrame->PersonalityEncoding = Encoding;
577 }
578 
579 void MCStreamer::emitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
580   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
581   if (!CurFrame)
582     return;
583   CurFrame->Lsda = Sym;
584   CurFrame->LsdaEncoding = Encoding;
585 }
586 
587 void MCStreamer::emitCFIRememberState(SMLoc Loc) {
588   MCSymbol *Label = emitCFILabel();
589   MCCFIInstruction Instruction =
590       MCCFIInstruction::createRememberState(Label, Loc);
591   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
592   if (!CurFrame)
593     return;
594   CurFrame->Instructions.push_back(Instruction);
595 }
596 
597 void MCStreamer::emitCFIRestoreState(SMLoc Loc) {
598   // FIXME: Error if there is no matching cfi_remember_state.
599   MCSymbol *Label = emitCFILabel();
600   MCCFIInstruction Instruction =
601       MCCFIInstruction::createRestoreState(Label, Loc);
602   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
603   if (!CurFrame)
604     return;
605   CurFrame->Instructions.push_back(Instruction);
606 }
607 
608 void MCStreamer::emitCFISameValue(int64_t Register, SMLoc Loc) {
609   MCSymbol *Label = emitCFILabel();
610   MCCFIInstruction Instruction =
611       MCCFIInstruction::createSameValue(Label, Register, Loc);
612   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
613   if (!CurFrame)
614     return;
615   CurFrame->Instructions.push_back(Instruction);
616 }
617 
618 void MCStreamer::emitCFIRestore(int64_t Register, SMLoc Loc) {
619   MCSymbol *Label = emitCFILabel();
620   MCCFIInstruction Instruction =
621       MCCFIInstruction::createRestore(Label, Register, Loc);
622   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
623   if (!CurFrame)
624     return;
625   CurFrame->Instructions.push_back(Instruction);
626 }
627 
628 void MCStreamer::emitCFIEscape(StringRef Values, SMLoc Loc) {
629   MCSymbol *Label = emitCFILabel();
630   MCCFIInstruction Instruction =
631       MCCFIInstruction::createEscape(Label, Values, Loc, "");
632   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
633   if (!CurFrame)
634     return;
635   CurFrame->Instructions.push_back(Instruction);
636 }
637 
638 void MCStreamer::emitCFIGnuArgsSize(int64_t Size, SMLoc Loc) {
639   MCSymbol *Label = emitCFILabel();
640   MCCFIInstruction Instruction =
641       MCCFIInstruction::createGnuArgsSize(Label, Size, Loc);
642   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
643   if (!CurFrame)
644     return;
645   CurFrame->Instructions.push_back(Instruction);
646 }
647 
648 void MCStreamer::emitCFISignalFrame() {
649   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
650   if (!CurFrame)
651     return;
652   CurFrame->IsSignalFrame = true;
653 }
654 
655 void MCStreamer::emitCFIUndefined(int64_t Register, SMLoc Loc) {
656   MCSymbol *Label = emitCFILabel();
657   MCCFIInstruction Instruction =
658       MCCFIInstruction::createUndefined(Label, Register, Loc);
659   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
660   if (!CurFrame)
661     return;
662   CurFrame->Instructions.push_back(Instruction);
663 }
664 
665 void MCStreamer::emitCFIRegister(int64_t Register1, int64_t Register2,
666                                  SMLoc Loc) {
667   MCSymbol *Label = emitCFILabel();
668   MCCFIInstruction Instruction =
669       MCCFIInstruction::createRegister(Label, Register1, Register2, Loc);
670   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
671   if (!CurFrame)
672     return;
673   CurFrame->Instructions.push_back(Instruction);
674 }
675 
676 void MCStreamer::emitCFIWindowSave(SMLoc Loc) {
677   MCSymbol *Label = emitCFILabel();
678   MCCFIInstruction Instruction = MCCFIInstruction::createWindowSave(Label, Loc);
679   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
680   if (!CurFrame)
681     return;
682   CurFrame->Instructions.push_back(Instruction);
683 }
684 
685 void MCStreamer::emitCFINegateRAState(SMLoc Loc) {
686   MCSymbol *Label = emitCFILabel();
687   MCCFIInstruction Instruction =
688       MCCFIInstruction::createNegateRAState(Label, Loc);
689   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
690   if (!CurFrame)
691     return;
692   CurFrame->Instructions.push_back(Instruction);
693 }
694 
695 void MCStreamer::emitCFIReturnColumn(int64_t Register) {
696   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
697   if (!CurFrame)
698     return;
699   CurFrame->RAReg = Register;
700 }
701 
702 WinEH::FrameInfo *MCStreamer::EnsureValidWinFrameInfo(SMLoc Loc) {
703   const MCAsmInfo *MAI = Context.getAsmInfo();
704   if (!MAI->usesWindowsCFI()) {
705     getContext().reportError(
706         Loc, ".seh_* directives are not supported on this target");
707     return nullptr;
708   }
709   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End) {
710     getContext().reportError(
711         Loc, ".seh_ directive must appear within an active frame");
712     return nullptr;
713   }
714   return CurrentWinFrameInfo;
715 }
716 
717 void MCStreamer::emitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc) {
718   const MCAsmInfo *MAI = Context.getAsmInfo();
719   if (!MAI->usesWindowsCFI())
720     return getContext().reportError(
721         Loc, ".seh_* directives are not supported on this target");
722   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
723     getContext().reportError(
724         Loc, "Starting a function before ending the previous one!");
725 
726   MCSymbol *StartProc = emitCFILabel();
727 
728   CurrentProcWinFrameInfoStartIndex = WinFrameInfos.size();
729   WinFrameInfos.emplace_back(
730       std::make_unique<WinEH::FrameInfo>(Symbol, StartProc));
731   CurrentWinFrameInfo = WinFrameInfos.back().get();
732   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
733 }
734 
735 void MCStreamer::emitWinCFIEndProc(SMLoc Loc) {
736   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
737   if (!CurFrame)
738     return;
739   if (CurFrame->ChainedParent)
740     getContext().reportError(Loc, "Not all chained regions terminated!");
741 
742   MCSymbol *Label = emitCFILabel();
743   CurFrame->End = Label;
744   if (!CurFrame->FuncletOrFuncEnd)
745     CurFrame->FuncletOrFuncEnd = CurFrame->End;
746 
747   for (size_t I = CurrentProcWinFrameInfoStartIndex, E = WinFrameInfos.size();
748        I != E; ++I)
749     emitWindowsUnwindTables(WinFrameInfos[I].get());
750   switchSection(CurFrame->TextSection);
751 }
752 
753 void MCStreamer::emitWinCFIFuncletOrFuncEnd(SMLoc Loc) {
754   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
755   if (!CurFrame)
756     return;
757   if (CurFrame->ChainedParent)
758     getContext().reportError(Loc, "Not all chained regions terminated!");
759 
760   MCSymbol *Label = emitCFILabel();
761   CurFrame->FuncletOrFuncEnd = Label;
762 }
763 
764 void MCStreamer::emitWinCFIStartChained(SMLoc Loc) {
765   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
766   if (!CurFrame)
767     return;
768 
769   MCSymbol *StartProc = emitCFILabel();
770 
771   WinFrameInfos.emplace_back(std::make_unique<WinEH::FrameInfo>(
772       CurFrame->Function, StartProc, CurFrame));
773   CurrentWinFrameInfo = WinFrameInfos.back().get();
774   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
775 }
776 
777 void MCStreamer::emitWinCFIEndChained(SMLoc Loc) {
778   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
779   if (!CurFrame)
780     return;
781   if (!CurFrame->ChainedParent)
782     return getContext().reportError(
783         Loc, "End of a chained region outside a chained region!");
784 
785   MCSymbol *Label = emitCFILabel();
786 
787   CurFrame->End = Label;
788   CurrentWinFrameInfo = const_cast<WinEH::FrameInfo *>(CurFrame->ChainedParent);
789 }
790 
791 void MCStreamer::emitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
792                                   SMLoc Loc) {
793   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
794   if (!CurFrame)
795     return;
796   if (CurFrame->ChainedParent)
797     return getContext().reportError(
798         Loc, "Chained unwind areas can't have handlers!");
799   CurFrame->ExceptionHandler = Sym;
800   if (!Except && !Unwind)
801     getContext().reportError(Loc, "Don't know what kind of handler this is!");
802   if (Unwind)
803     CurFrame->HandlesUnwind = true;
804   if (Except)
805     CurFrame->HandlesExceptions = true;
806 }
807 
808 void MCStreamer::emitWinEHHandlerData(SMLoc Loc) {
809   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
810   if (!CurFrame)
811     return;
812   if (CurFrame->ChainedParent)
813     getContext().reportError(Loc, "Chained unwind areas can't have handlers!");
814 }
815 
816 void MCStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
817                                     const MCSymbolRefExpr *To, uint64_t Count) {
818 }
819 
820 static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
821                                    MCSection *MainCFISec,
822                                    const MCSection *TextSec) {
823   // If this is the main .text section, use the main unwind info section.
824   if (TextSec == Context.getObjectFileInfo()->getTextSection())
825     return MainCFISec;
826 
827   const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
828   auto *MainCFISecCOFF = cast<MCSectionCOFF>(MainCFISec);
829   unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
830 
831   // If this section is COMDAT, this unwind section should be COMDAT associative
832   // with its group.
833   const MCSymbol *KeySym = nullptr;
834   if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
835     KeySym = TextSecCOFF->getCOMDATSymbol();
836 
837     // In a GNU environment, we can't use associative comdats. Instead, do what
838     // GCC does, which is to make plain comdat selectany section named like
839     // ".[px]data$_Z3foov".
840     if (!Context.getAsmInfo()->hasCOFFAssociativeComdats()) {
841       std::string SectionName = (MainCFISecCOFF->getName() + "$" +
842                                  TextSecCOFF->getName().split('$').second)
843                                     .str();
844       return Context.getCOFFSection(
845           SectionName,
846           MainCFISecCOFF->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT,
847           MainCFISecCOFF->getKind(), "", COFF::IMAGE_COMDAT_SELECT_ANY);
848     }
849   }
850 
851   return Context.getAssociativeCOFFSection(MainCFISecCOFF, KeySym, UniqueID);
852 }
853 
854 MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
855   return getWinCFISection(getContext(), &NextWinCFIID,
856                           getContext().getObjectFileInfo()->getPDataSection(),
857                           TextSec);
858 }
859 
860 MCSection *MCStreamer::getAssociatedXDataSection(const MCSection *TextSec) {
861   return getWinCFISection(getContext(), &NextWinCFIID,
862                           getContext().getObjectFileInfo()->getXDataSection(),
863                           TextSec);
864 }
865 
866 void MCStreamer::emitSyntaxDirective() {}
867 
868 static unsigned encodeSEHRegNum(MCContext &Ctx, MCRegister Reg) {
869   return Ctx.getRegisterInfo()->getSEHRegNum(Reg);
870 }
871 
872 void MCStreamer::emitWinCFIPushReg(MCRegister Register, SMLoc Loc) {
873   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
874   if (!CurFrame)
875     return;
876 
877   MCSymbol *Label = emitCFILabel();
878 
879   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(
880       Label, encodeSEHRegNum(Context, Register));
881   CurFrame->Instructions.push_back(Inst);
882 }
883 
884 void MCStreamer::emitWinCFISetFrame(MCRegister Register, unsigned Offset,
885                                     SMLoc Loc) {
886   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
887   if (!CurFrame)
888     return;
889   if (CurFrame->LastFrameInst >= 0)
890     return getContext().reportError(
891         Loc, "frame register and offset can be set at most once");
892   if (Offset & 0x0F)
893     return getContext().reportError(Loc, "offset is not a multiple of 16");
894   if (Offset > 240)
895     return getContext().reportError(
896         Loc, "frame offset must be less than or equal to 240");
897 
898   MCSymbol *Label = emitCFILabel();
899 
900   WinEH::Instruction Inst = Win64EH::Instruction::SetFPReg(
901       Label, encodeSEHRegNum(getContext(), Register), Offset);
902   CurFrame->LastFrameInst = CurFrame->Instructions.size();
903   CurFrame->Instructions.push_back(Inst);
904 }
905 
906 void MCStreamer::emitWinCFIAllocStack(unsigned Size, SMLoc Loc) {
907   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
908   if (!CurFrame)
909     return;
910   if (Size == 0)
911     return getContext().reportError(Loc,
912                                     "stack allocation size must be non-zero");
913   if (Size & 7)
914     return getContext().reportError(
915         Loc, "stack allocation size is not a multiple of 8");
916 
917   MCSymbol *Label = emitCFILabel();
918 
919   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
920   CurFrame->Instructions.push_back(Inst);
921 }
922 
923 void MCStreamer::emitWinCFISaveReg(MCRegister Register, unsigned Offset,
924                                    SMLoc Loc) {
925   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
926   if (!CurFrame)
927     return;
928 
929   if (Offset & 7)
930     return getContext().reportError(
931         Loc, "register save offset is not 8 byte aligned");
932 
933   MCSymbol *Label = emitCFILabel();
934 
935   WinEH::Instruction Inst = Win64EH::Instruction::SaveNonVol(
936       Label, encodeSEHRegNum(Context, Register), Offset);
937   CurFrame->Instructions.push_back(Inst);
938 }
939 
940 void MCStreamer::emitWinCFISaveXMM(MCRegister Register, unsigned Offset,
941                                    SMLoc Loc) {
942   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
943   if (!CurFrame)
944     return;
945   if (Offset & 0x0F)
946     return getContext().reportError(Loc, "offset is not a multiple of 16");
947 
948   MCSymbol *Label = emitCFILabel();
949 
950   WinEH::Instruction Inst = Win64EH::Instruction::SaveXMM(
951       Label, encodeSEHRegNum(Context, Register), Offset);
952   CurFrame->Instructions.push_back(Inst);
953 }
954 
955 void MCStreamer::emitWinCFIPushFrame(bool Code, SMLoc Loc) {
956   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
957   if (!CurFrame)
958     return;
959   if (!CurFrame->Instructions.empty())
960     return getContext().reportError(
961         Loc, "If present, PushMachFrame must be the first UOP");
962 
963   MCSymbol *Label = emitCFILabel();
964 
965   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
966   CurFrame->Instructions.push_back(Inst);
967 }
968 
969 void MCStreamer::emitWinCFIEndProlog(SMLoc Loc) {
970   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
971   if (!CurFrame)
972     return;
973 
974   MCSymbol *Label = emitCFILabel();
975 
976   CurFrame->PrologEnd = Label;
977 }
978 
979 void MCStreamer::emitCOFFSafeSEH(MCSymbol const *Symbol) {}
980 
981 void MCStreamer::emitCOFFSymbolIndex(MCSymbol const *Symbol) {}
982 
983 void MCStreamer::emitCOFFSectionIndex(MCSymbol const *Symbol) {}
984 
985 void MCStreamer::emitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {}
986 
987 void MCStreamer::emitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) {}
988 
989 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
990 /// the specified string in the output .s file.  This capability is
991 /// indicated by the hasRawTextSupport() predicate.
992 void MCStreamer::emitRawTextImpl(StringRef String) {
993   // This is not llvm_unreachable for the sake of out of tree backend
994   // developers who may not have assembly streamers and should serve as a
995   // reminder to not accidentally call EmitRawText in the absence of such.
996   report_fatal_error("EmitRawText called on an MCStreamer that doesn't support "
997                      "it (target backend is likely missing an AsmStreamer "
998                      "implementation)");
999 }
1000 
1001 void MCStreamer::emitRawText(const Twine &T) {
1002   SmallString<128> Str;
1003   emitRawTextImpl(T.toStringRef(Str));
1004 }
1005 
1006 void MCStreamer::emitWindowsUnwindTables() {}
1007 
1008 void MCStreamer::emitWindowsUnwindTables(WinEH::FrameInfo *Frame) {}
1009 
1010 void MCStreamer::finish(SMLoc EndLoc) {
1011   if ((!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End) ||
1012       (!WinFrameInfos.empty() && !WinFrameInfos.back()->End)) {
1013     getContext().reportError(EndLoc, "Unfinished frame!");
1014     return;
1015   }
1016 
1017   MCTargetStreamer *TS = getTargetStreamer();
1018   if (TS)
1019     TS->finish();
1020 
1021   finishImpl();
1022 }
1023 
1024 void MCStreamer::maybeEmitDwarf64Mark() {
1025   if (Context.getDwarfFormat() != dwarf::DWARF64)
1026     return;
1027   AddComment("DWARF64 Mark");
1028   emitInt32(dwarf::DW_LENGTH_DWARF64);
1029 }
1030 
1031 void MCStreamer::emitDwarfUnitLength(uint64_t Length, const Twine &Comment) {
1032   assert(Context.getDwarfFormat() == dwarf::DWARF64 ||
1033          Length <= dwarf::DW_LENGTH_lo_reserved);
1034   maybeEmitDwarf64Mark();
1035   AddComment(Comment);
1036   emitIntValue(Length, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1037 }
1038 
1039 MCSymbol *MCStreamer::emitDwarfUnitLength(const Twine &Prefix,
1040                                           const Twine &Comment) {
1041   maybeEmitDwarf64Mark();
1042   AddComment(Comment);
1043   MCSymbol *Lo = Context.createTempSymbol(Prefix + "_start");
1044   MCSymbol *Hi = Context.createTempSymbol(Prefix + "_end");
1045 
1046   emitAbsoluteSymbolDiff(
1047       Hi, Lo, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1048   // emit the begin symbol after we generate the length field.
1049   emitLabel(Lo);
1050   // Return the Hi symbol to the caller.
1051   return Hi;
1052 }
1053 
1054 void MCStreamer::emitDwarfLineStartLabel(MCSymbol *StartSym) {
1055   // Set the value of the symbol, as we are at the start of the line table.
1056   emitLabel(StartSym);
1057 }
1058 
1059 void MCStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
1060   visitUsedExpr(*Value);
1061   Symbol->setVariableValue(Value);
1062 
1063   MCTargetStreamer *TS = getTargetStreamer();
1064   if (TS)
1065     TS->emitAssignment(Symbol, Value);
1066 }
1067 
1068 void MCTargetStreamer::prettyPrintAsm(MCInstPrinter &InstPrinter,
1069                                       uint64_t Address, const MCInst &Inst,
1070                                       const MCSubtargetInfo &STI,
1071                                       raw_ostream &OS) {
1072   InstPrinter.printInst(&Inst, Address, "", STI, OS);
1073 }
1074 
1075 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
1076 }
1077 
1078 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
1079   switch (Expr.getKind()) {
1080   case MCExpr::Target:
1081     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
1082     break;
1083 
1084   case MCExpr::Constant:
1085     break;
1086 
1087   case MCExpr::Binary: {
1088     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
1089     visitUsedExpr(*BE.getLHS());
1090     visitUsedExpr(*BE.getRHS());
1091     break;
1092   }
1093 
1094   case MCExpr::SymbolRef:
1095     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
1096     break;
1097 
1098   case MCExpr::Unary:
1099     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
1100     break;
1101   }
1102 }
1103 
1104 void MCStreamer::emitInstruction(const MCInst &Inst, const MCSubtargetInfo &) {
1105   // Scan for values.
1106   for (unsigned i = Inst.getNumOperands(); i--;)
1107     if (Inst.getOperand(i).isExpr())
1108       visitUsedExpr(*Inst.getOperand(i).getExpr());
1109 }
1110 
1111 void MCStreamer::emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
1112                                  uint64_t Attr, uint64_t Discriminator,
1113                                  const MCPseudoProbeInlineStack &InlineStack,
1114                                  MCSymbol *FnSym) {
1115   auto &Context = getContext();
1116 
1117   // Create a symbol at in the current section for use in the probe.
1118   MCSymbol *ProbeSym = Context.createTempSymbol();
1119 
1120   // Set the value of the symbol to use for the MCPseudoProbe.
1121   emitLabel(ProbeSym);
1122 
1123   // Create a (local) probe entry with the symbol.
1124   MCPseudoProbe Probe(ProbeSym, Guid, Index, Type, Attr, Discriminator);
1125 
1126   // Add the probe entry to this section's entries.
1127   Context.getMCPseudoProbeTable().getProbeSections().addPseudoProbe(
1128       FnSym, Probe, InlineStack);
1129 }
1130 
1131 void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
1132                                         unsigned Size) {
1133   // Get the Hi-Lo expression.
1134   const MCExpr *Diff =
1135       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1136                               MCSymbolRefExpr::create(Lo, Context), Context);
1137 
1138   const MCAsmInfo *MAI = Context.getAsmInfo();
1139   if (!MAI->doesSetDirectiveSuppressReloc()) {
1140     emitValue(Diff, Size);
1141     return;
1142   }
1143 
1144   // Otherwise, emit with .set (aka assignment).
1145   MCSymbol *SetLabel = Context.createTempSymbol("set");
1146   emitAssignment(SetLabel, Diff);
1147   emitSymbolValue(SetLabel, Size);
1148 }
1149 
1150 void MCStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
1151                                                  const MCSymbol *Lo) {
1152   // Get the Hi-Lo expression.
1153   const MCExpr *Diff =
1154       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1155                               MCSymbolRefExpr::create(Lo, Context), Context);
1156 
1157   emitULEB128Value(Diff);
1158 }
1159 
1160 void MCStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {}
1161 void MCStreamer::emitThumbFunc(MCSymbol *Func) {}
1162 void MCStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
1163 void MCStreamer::beginCOFFSymbolDef(const MCSymbol *Symbol) {
1164   llvm_unreachable("this directive only supported on COFF targets");
1165 }
1166 void MCStreamer::endCOFFSymbolDef() {
1167   llvm_unreachable("this directive only supported on COFF targets");
1168 }
1169 void MCStreamer::emitFileDirective(StringRef Filename) {}
1170 void MCStreamer::emitFileDirective(StringRef Filename, StringRef CompilerVerion,
1171                                    StringRef TimeStamp, StringRef Description) {
1172 }
1173 void MCStreamer::emitCOFFSymbolStorageClass(int StorageClass) {
1174   llvm_unreachable("this directive only supported on COFF targets");
1175 }
1176 void MCStreamer::emitCOFFSymbolType(int Type) {
1177   llvm_unreachable("this directive only supported on COFF targets");
1178 }
1179 void MCStreamer::emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
1180                                             MCSymbol *CsectSym,
1181                                             Align Alignment) {
1182   llvm_unreachable("this directive only supported on XCOFF targets");
1183 }
1184 
1185 void MCStreamer::emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol,
1186                                                       MCSymbolAttr Linkage,
1187                                                       MCSymbolAttr Visibility) {
1188   llvm_unreachable("emitXCOFFSymbolLinkageWithVisibility is only supported on "
1189                    "XCOFF targets");
1190 }
1191 
1192 void MCStreamer::emitXCOFFRenameDirective(const MCSymbol *Name,
1193                                           StringRef Rename) {
1194   llvm_unreachable("emitXCOFFRenameDirective is only supported on "
1195                    "XCOFF targets");
1196 }
1197 
1198 void MCStreamer::emitXCOFFRefDirective(const MCSymbol *Symbol) {
1199   llvm_unreachable("emitXCOFFRefDirective is only supported on XCOFF targets");
1200 }
1201 
1202 void MCStreamer::emitXCOFFExceptDirective(const MCSymbol *Symbol,
1203                                           const MCSymbol *Trap,
1204                                           unsigned Lang, unsigned Reason,
1205                                           unsigned FunctionSize,
1206                                           bool hasDebug) {
1207   report_fatal_error("emitXCOFFExceptDirective is only supported on "
1208                      "XCOFF targets");
1209 }
1210 
1211 void MCStreamer::emitXCOFFCInfoSym(StringRef Name, StringRef Metadata) {
1212   llvm_unreachable("emitXCOFFCInfoSym is only supported on"
1213                    "XCOFF targets");
1214 }
1215 
1216 void MCStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
1217 void MCStreamer::emitELFSymverDirective(const MCSymbol *OriginalSym,
1218                                         StringRef Name, bool KeepOriginalSym) {}
1219 void MCStreamer::emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
1220                                        Align ByteAlignment) {}
1221 void MCStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
1222                                 uint64_t Size, Align ByteAlignment) {}
1223 void MCStreamer::changeSection(MCSection *, const MCExpr *) {}
1224 void MCStreamer::emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
1225 void MCStreamer::emitBytes(StringRef Data) {}
1226 void MCStreamer::emitBinaryData(StringRef Data) { emitBytes(Data); }
1227 void MCStreamer::emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) {
1228   visitUsedExpr(*Value);
1229 }
1230 void MCStreamer::emitULEB128Value(const MCExpr *Value) {}
1231 void MCStreamer::emitSLEB128Value(const MCExpr *Value) {}
1232 void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc Loc) {}
1233 void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
1234                           SMLoc Loc) {}
1235 void MCStreamer::emitValueToAlignment(Align Alignment, int64_t Value,
1236                                       unsigned ValueSize,
1237                                       unsigned MaxBytesToEmit) {}
1238 void MCStreamer::emitCodeAlignment(Align Alignment, const MCSubtargetInfo *STI,
1239                                    unsigned MaxBytesToEmit) {}
1240 void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value,
1241                                    SMLoc Loc) {}
1242 void MCStreamer::emitBundleAlignMode(Align Alignment) {}
1243 void MCStreamer::emitBundleLock(bool AlignToEnd) {}
1244 void MCStreamer::finishImpl() {}
1245 void MCStreamer::emitBundleUnlock() {}
1246 
1247 void MCStreamer::switchSection(MCSection *Section, const MCExpr *Subsection) {
1248   assert(Section && "Cannot switch to a null section!");
1249   MCSectionSubPair curSection = SectionStack.back().first;
1250   SectionStack.back().second = curSection;
1251   if (MCSectionSubPair(Section, Subsection) != curSection) {
1252     changeSection(Section, Subsection);
1253     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
1254     assert(!Section->hasEnded() && "Section already ended");
1255     MCSymbol *Sym = Section->getBeginSymbol();
1256     if (Sym && !Sym->isInSection())
1257       emitLabel(Sym);
1258   }
1259 }
1260 
1261 MCSymbol *MCStreamer::endSection(MCSection *Section) {
1262   // TODO: keep track of the last subsection so that this symbol appears in the
1263   // correct place.
1264   MCSymbol *Sym = Section->getEndSymbol(Context);
1265   if (Sym->isInSection())
1266     return Sym;
1267 
1268   switchSection(Section);
1269   emitLabel(Sym);
1270   return Sym;
1271 }
1272 
1273 static VersionTuple
1274 targetVersionOrMinimumSupportedOSVersion(const Triple &Target,
1275                                          VersionTuple TargetVersion) {
1276   VersionTuple Min = Target.getMinimumSupportedOSVersion();
1277   return !Min.empty() && Min > TargetVersion ? Min : TargetVersion;
1278 }
1279 
1280 static MCVersionMinType
1281 getMachoVersionMinLoadCommandType(const Triple &Target) {
1282   assert(Target.isOSDarwin() && "expected a darwin OS");
1283   switch (Target.getOS()) {
1284   case Triple::MacOSX:
1285   case Triple::Darwin:
1286     return MCVM_OSXVersionMin;
1287   case Triple::IOS:
1288     assert(!Target.isMacCatalystEnvironment() &&
1289            "mac Catalyst should use LC_BUILD_VERSION");
1290     return MCVM_IOSVersionMin;
1291   case Triple::TvOS:
1292     return MCVM_TvOSVersionMin;
1293   case Triple::WatchOS:
1294     return MCVM_WatchOSVersionMin;
1295   default:
1296     break;
1297   }
1298   llvm_unreachable("unexpected OS type");
1299 }
1300 
1301 static VersionTuple getMachoBuildVersionSupportedOS(const Triple &Target) {
1302   assert(Target.isOSDarwin() && "expected a darwin OS");
1303   switch (Target.getOS()) {
1304   case Triple::MacOSX:
1305   case Triple::Darwin:
1306     return VersionTuple(10, 14);
1307   case Triple::IOS:
1308     // Mac Catalyst always uses the build version load command.
1309     if (Target.isMacCatalystEnvironment())
1310       return VersionTuple();
1311     [[fallthrough]];
1312   case Triple::TvOS:
1313     return VersionTuple(12);
1314   case Triple::WatchOS:
1315     return VersionTuple(5);
1316   case Triple::DriverKit:
1317     // DriverKit always uses the build version load command.
1318     return VersionTuple();
1319   default:
1320     break;
1321   }
1322   llvm_unreachable("unexpected OS type");
1323 }
1324 
1325 static MachO::PlatformType
1326 getMachoBuildVersionPlatformType(const Triple &Target) {
1327   assert(Target.isOSDarwin() && "expected a darwin OS");
1328   switch (Target.getOS()) {
1329   case Triple::MacOSX:
1330   case Triple::Darwin:
1331     return MachO::PLATFORM_MACOS;
1332   case Triple::IOS:
1333     if (Target.isMacCatalystEnvironment())
1334       return MachO::PLATFORM_MACCATALYST;
1335     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_IOSSIMULATOR
1336                                            : MachO::PLATFORM_IOS;
1337   case Triple::TvOS:
1338     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_TVOSSIMULATOR
1339                                            : MachO::PLATFORM_TVOS;
1340   case Triple::WatchOS:
1341     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_WATCHOSSIMULATOR
1342                                            : MachO::PLATFORM_WATCHOS;
1343   case Triple::DriverKit:
1344     return MachO::PLATFORM_DRIVERKIT;
1345   default:
1346     break;
1347   }
1348   llvm_unreachable("unexpected OS type");
1349 }
1350 
1351 void MCStreamer::emitVersionForTarget(
1352     const Triple &Target, const VersionTuple &SDKVersion,
1353     const Triple *DarwinTargetVariantTriple,
1354     const VersionTuple &DarwinTargetVariantSDKVersion) {
1355   if (!Target.isOSBinFormatMachO() || !Target.isOSDarwin())
1356     return;
1357   // Do we even know the version?
1358   if (Target.getOSMajorVersion() == 0)
1359     return;
1360 
1361   VersionTuple Version;
1362   switch (Target.getOS()) {
1363   case Triple::MacOSX:
1364   case Triple::Darwin:
1365     Target.getMacOSXVersion(Version);
1366     break;
1367   case Triple::IOS:
1368   case Triple::TvOS:
1369     Version = Target.getiOSVersion();
1370     break;
1371   case Triple::WatchOS:
1372     Version = Target.getWatchOSVersion();
1373     break;
1374   case Triple::DriverKit:
1375     Version = Target.getDriverKitVersion();
1376     break;
1377   default:
1378     llvm_unreachable("unexpected OS type");
1379   }
1380   assert(Version.getMajor() != 0 && "A non-zero major version is expected");
1381   auto LinkedTargetVersion =
1382       targetVersionOrMinimumSupportedOSVersion(Target, Version);
1383   auto BuildVersionOSVersion = getMachoBuildVersionSupportedOS(Target);
1384   bool ShouldEmitBuildVersion = false;
1385   if (BuildVersionOSVersion.empty() ||
1386       LinkedTargetVersion >= BuildVersionOSVersion) {
1387     if (Target.isMacCatalystEnvironment() && DarwinTargetVariantTriple &&
1388         DarwinTargetVariantTriple->isMacOSX()) {
1389       emitVersionForTarget(*DarwinTargetVariantTriple,
1390                            DarwinTargetVariantSDKVersion,
1391                            /*DarwinTargetVariantTriple=*/nullptr,
1392                            /*DarwinTargetVariantSDKVersion=*/VersionTuple());
1393       emitDarwinTargetVariantBuildVersion(
1394           getMachoBuildVersionPlatformType(Target),
1395           LinkedTargetVersion.getMajor(),
1396           LinkedTargetVersion.getMinor().value_or(0),
1397           LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1398       return;
1399     }
1400     emitBuildVersion(getMachoBuildVersionPlatformType(Target),
1401                      LinkedTargetVersion.getMajor(),
1402                      LinkedTargetVersion.getMinor().value_or(0),
1403                      LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1404     ShouldEmitBuildVersion = true;
1405   }
1406 
1407   if (const Triple *TVT = DarwinTargetVariantTriple) {
1408     if (Target.isMacOSX() && TVT->isMacCatalystEnvironment()) {
1409       auto TVLinkedTargetVersion =
1410           targetVersionOrMinimumSupportedOSVersion(*TVT, TVT->getiOSVersion());
1411       emitDarwinTargetVariantBuildVersion(
1412           getMachoBuildVersionPlatformType(*TVT),
1413           TVLinkedTargetVersion.getMajor(),
1414           TVLinkedTargetVersion.getMinor().value_or(0),
1415           TVLinkedTargetVersion.getSubminor().value_or(0),
1416           DarwinTargetVariantSDKVersion);
1417     }
1418   }
1419 
1420   if (ShouldEmitBuildVersion)
1421     return;
1422 
1423   emitVersionMin(getMachoVersionMinLoadCommandType(Target),
1424                  LinkedTargetVersion.getMajor(),
1425                  LinkedTargetVersion.getMinor().value_or(0),
1426                  LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1427 }
1428