xref: /freebsd/contrib/llvm-project/llvm/lib/MC/MCStreamer.cpp (revision 4824e7fd18a1223177218d4aec1b3c6c5c4a444e) 
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/Optional.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/StringRef.h"
13 #include "llvm/ADT/Twine.h"
14 #include "llvm/BinaryFormat/COFF.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 <utility>
42 
43 using namespace llvm;
44 
45 MCTargetStreamer::MCTargetStreamer(MCStreamer &S) : Streamer(S) {
46   S.setTargetStreamer(this);
47 }
48 
49 // Pin the vtables to this file.
50 MCTargetStreamer::~MCTargetStreamer() = default;
51 
52 void MCTargetStreamer::emitLabel(MCSymbol *Symbol) {}
53 
54 void MCTargetStreamer::finish() {}
55 
56 void MCTargetStreamer::emitConstantPools() {}
57 
58 void MCTargetStreamer::changeSection(const MCSection *CurSection,
59                                      MCSection *Section,
60                                      const MCExpr *Subsection,
61                                      raw_ostream &OS) {
62   Section->PrintSwitchToSection(*Streamer.getContext().getAsmInfo(),
63                                 Streamer.getContext().getTargetTriple(), OS,
64                                 Subsection);
65 }
66 
67 void MCTargetStreamer::emitDwarfFileDirective(StringRef Directive) {
68   Streamer.emitRawText(Directive);
69 }
70 
71 void MCTargetStreamer::emitValue(const MCExpr *Value) {
72   SmallString<128> Str;
73   raw_svector_ostream OS(Str);
74 
75   Value->print(OS, Streamer.getContext().getAsmInfo());
76   Streamer.emitRawText(OS.str());
77 }
78 
79 void MCTargetStreamer::emitRawBytes(StringRef Data) {
80   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
81   const char *Directive = MAI->getData8bitsDirective();
82   for (const unsigned char C : Data.bytes()) {
83     SmallString<128> Str;
84     raw_svector_ostream OS(Str);
85 
86     OS << Directive << (unsigned)C;
87     Streamer.emitRawText(OS.str());
88   }
89 }
90 
91 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
92 
93 MCStreamer::MCStreamer(MCContext &Ctx)
94     : Context(Ctx), CurrentWinFrameInfo(nullptr),
95       CurrentProcWinFrameInfoStartIndex(0), UseAssemblerInfoForParsing(false) {
96   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
97 }
98 
99 MCStreamer::~MCStreamer() {}
100 
101 void MCStreamer::reset() {
102   DwarfFrameInfos.clear();
103   CurrentWinFrameInfo = nullptr;
104   WinFrameInfos.clear();
105   SymbolOrdering.clear();
106   SectionStack.clear();
107   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
108 }
109 
110 raw_ostream &MCStreamer::GetCommentOS() {
111   // By default, discard comments.
112   return nulls();
113 }
114 
115 unsigned MCStreamer::getNumFrameInfos() { return DwarfFrameInfos.size(); }
116 ArrayRef<MCDwarfFrameInfo> MCStreamer::getDwarfFrameInfos() const {
117   return DwarfFrameInfos;
118 }
119 
120 void MCStreamer::emitRawComment(const Twine &T, bool TabPrefix) {}
121 
122 void MCStreamer::addExplicitComment(const Twine &T) {}
123 void MCStreamer::emitExplicitComments() {}
124 
125 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
126   for (auto &FI : DwarfFrameInfos)
127     FI.CompactUnwindEncoding =
128         (MAB ? MAB->generateCompactUnwindEncoding(FI.Instructions) : 0);
129 }
130 
131 /// EmitIntValue - Special case of EmitValue that avoids the client having to
132 /// pass in a MCExpr for constant integers.
133 void MCStreamer::emitIntValue(uint64_t Value, unsigned Size) {
134   assert(1 <= Size && Size <= 8 && "Invalid size");
135   assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
136          "Invalid size");
137   const bool IsLittleEndian = Context.getAsmInfo()->isLittleEndian();
138   uint64_t Swapped = support::endian::byte_swap(
139       Value, IsLittleEndian ? support::little : support::big);
140   unsigned Index = IsLittleEndian ? 0 : 8 - Size;
141   emitBytes(StringRef(reinterpret_cast<char *>(&Swapped) + Index, Size));
142 }
143 void MCStreamer::emitIntValue(APInt Value) {
144   if (Value.getNumWords() == 1) {
145     emitIntValue(Value.getLimitedValue(), Value.getBitWidth() / 8);
146     return;
147   }
148 
149   const bool IsLittleEndianTarget = Context.getAsmInfo()->isLittleEndian();
150   const bool ShouldSwap = sys::IsLittleEndianHost != IsLittleEndianTarget;
151   const APInt Swapped = ShouldSwap ? Value.byteSwap() : Value;
152   const unsigned Size = Value.getBitWidth() / 8;
153   SmallString<10> Tmp;
154   Tmp.resize(Size);
155   StoreIntToMemory(Swapped, reinterpret_cast<uint8_t *>(Tmp.data()), Size);
156   emitBytes(Tmp.str());
157 }
158 
159 /// EmitULEB128IntValue - Special case of EmitULEB128Value that avoids the
160 /// client having to pass in a MCExpr for constant integers.
161 void MCStreamer::emitULEB128IntValue(uint64_t Value, unsigned PadTo) {
162   SmallString<128> Tmp;
163   raw_svector_ostream OSE(Tmp);
164   encodeULEB128(Value, OSE, PadTo);
165   emitBytes(OSE.str());
166 }
167 
168 /// EmitSLEB128IntValue - Special case of EmitSLEB128Value that avoids the
169 /// client having to pass in a MCExpr for constant integers.
170 void MCStreamer::emitSLEB128IntValue(int64_t Value) {
171   SmallString<128> Tmp;
172   raw_svector_ostream OSE(Tmp);
173   encodeSLEB128(Value, OSE);
174   emitBytes(OSE.str());
175 }
176 
177 void MCStreamer::emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc) {
178   emitValueImpl(Value, Size, Loc);
179 }
180 
181 void MCStreamer::emitSymbolValue(const MCSymbol *Sym, unsigned Size,
182                                  bool IsSectionRelative) {
183   assert((!IsSectionRelative || Size == 4) &&
184          "SectionRelative value requires 4-bytes");
185 
186   if (!IsSectionRelative)
187     emitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
188   else
189     EmitCOFFSecRel32(Sym, /*Offset=*/0);
190 }
191 
192 void MCStreamer::emitDTPRel64Value(const MCExpr *Value) {
193   report_fatal_error("unsupported directive in streamer");
194 }
195 
196 void MCStreamer::emitDTPRel32Value(const MCExpr *Value) {
197   report_fatal_error("unsupported directive in streamer");
198 }
199 
200 void MCStreamer::emitTPRel64Value(const MCExpr *Value) {
201   report_fatal_error("unsupported directive in streamer");
202 }
203 
204 void MCStreamer::emitTPRel32Value(const MCExpr *Value) {
205   report_fatal_error("unsupported directive in streamer");
206 }
207 
208 void MCStreamer::emitGPRel64Value(const MCExpr *Value) {
209   report_fatal_error("unsupported directive in streamer");
210 }
211 
212 void MCStreamer::emitGPRel32Value(const MCExpr *Value) {
213   report_fatal_error("unsupported directive in streamer");
214 }
215 
216 /// Emit NumBytes bytes worth of the value specified by FillValue.
217 /// This implements directives such as '.space'.
218 void MCStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
219   emitFill(*MCConstantExpr::create(NumBytes, getContext()), FillValue);
220 }
221 
222 void llvm::MCStreamer::emitNops(int64_t NumBytes, int64_t ControlledNopLen,
223                                 llvm::SMLoc, const MCSubtargetInfo& STI) {}
224 
225 /// The implementation in this class just redirects to emitFill.
226 void MCStreamer::emitZeros(uint64_t NumBytes) { emitFill(NumBytes, 0); }
227 
228 Expected<unsigned>
229 MCStreamer::tryEmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
230                                       StringRef Filename,
231                                       Optional<MD5::MD5Result> Checksum,
232                                       Optional<StringRef> Source,
233                                       unsigned CUID) {
234   return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
235                                    Source, CUID);
236 }
237 
238 void MCStreamer::emitDwarfFile0Directive(StringRef Directory,
239                                          StringRef Filename,
240                                          Optional<MD5::MD5Result> Checksum,
241                                          Optional<StringRef> Source,
242                                          unsigned CUID) {
243   getContext().setMCLineTableRootFile(CUID, Directory, Filename, Checksum,
244                                       Source);
245 }
246 
247 void MCStreamer::emitCFIBKeyFrame() {
248   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
249   if (!CurFrame)
250     return;
251   CurFrame->IsBKeyFrame = true;
252 }
253 
254 void MCStreamer::emitDwarfLocDirective(unsigned FileNo, unsigned Line,
255                                        unsigned Column, unsigned Flags,
256                                        unsigned Isa, unsigned Discriminator,
257                                        StringRef FileName) {
258   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
259                                   Discriminator);
260 }
261 
262 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
263   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
264   if (!Table.getLabel()) {
265     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
266     Table.setLabel(
267         Context.getOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
268   }
269   return Table.getLabel();
270 }
271 
272 bool MCStreamer::hasUnfinishedDwarfFrameInfo() {
273   return !DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End;
274 }
275 
276 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
277   if (!hasUnfinishedDwarfFrameInfo()) {
278     getContext().reportError(getStartTokLoc(),
279                              "this directive must appear between "
280                              ".cfi_startproc and .cfi_endproc directives");
281     return nullptr;
282   }
283   return &DwarfFrameInfos.back();
284 }
285 
286 bool MCStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename,
287                                      ArrayRef<uint8_t> Checksum,
288                                      unsigned ChecksumKind) {
289   return getContext().getCVContext().addFile(*this, FileNo, Filename, Checksum,
290                                              ChecksumKind);
291 }
292 
293 bool MCStreamer::EmitCVFuncIdDirective(unsigned FunctionId) {
294   return getContext().getCVContext().recordFunctionId(FunctionId);
295 }
296 
297 bool MCStreamer::EmitCVInlineSiteIdDirective(unsigned FunctionId,
298                                              unsigned IAFunc, unsigned IAFile,
299                                              unsigned IALine, unsigned IACol,
300                                              SMLoc Loc) {
301   if (getContext().getCVContext().getCVFunctionInfo(IAFunc) == nullptr) {
302     getContext().reportError(Loc, "parent function id not introduced by "
303                                   ".cv_func_id or .cv_inline_site_id");
304     return true;
305   }
306 
307   return getContext().getCVContext().recordInlinedCallSiteId(
308       FunctionId, IAFunc, IAFile, IALine, IACol);
309 }
310 
311 void MCStreamer::emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
312                                     unsigned Line, unsigned Column,
313                                     bool PrologueEnd, bool IsStmt,
314                                     StringRef FileName, SMLoc Loc) {}
315 
316 bool MCStreamer::checkCVLocSection(unsigned FuncId, unsigned FileNo,
317                                    SMLoc Loc) {
318   CodeViewContext &CVC = getContext().getCVContext();
319   MCCVFunctionInfo *FI = CVC.getCVFunctionInfo(FuncId);
320   if (!FI) {
321     getContext().reportError(
322         Loc, "function id not introduced by .cv_func_id or .cv_inline_site_id");
323     return false;
324   }
325 
326   // Track the section
327   if (FI->Section == nullptr)
328     FI->Section = getCurrentSectionOnly();
329   else if (FI->Section != getCurrentSectionOnly()) {
330     getContext().reportError(
331         Loc,
332         "all .cv_loc directives for a function must be in the same section");
333     return false;
334   }
335   return true;
336 }
337 
338 void MCStreamer::emitCVLinetableDirective(unsigned FunctionId,
339                                           const MCSymbol *Begin,
340                                           const MCSymbol *End) {}
341 
342 void MCStreamer::emitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
343                                                 unsigned SourceFileId,
344                                                 unsigned SourceLineNum,
345                                                 const MCSymbol *FnStartSym,
346                                                 const MCSymbol *FnEndSym) {}
347 
348 /// Only call this on endian-specific types like ulittle16_t and little32_t, or
349 /// structs composed of them.
350 template <typename T>
351 static void copyBytesForDefRange(SmallString<20> &BytePrefix,
352                                  codeview::SymbolKind SymKind,
353                                  const T &DefRangeHeader) {
354   BytePrefix.resize(2 + sizeof(T));
355   codeview::ulittle16_t SymKindLE = codeview::ulittle16_t(SymKind);
356   memcpy(&BytePrefix[0], &SymKindLE, 2);
357   memcpy(&BytePrefix[2], &DefRangeHeader, sizeof(T));
358 }
359 
360 void MCStreamer::emitCVDefRangeDirective(
361     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
362     StringRef FixedSizePortion) {}
363 
364 void MCStreamer::emitCVDefRangeDirective(
365     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
366     codeview::DefRangeRegisterRelHeader DRHdr) {
367   SmallString<20> BytePrefix;
368   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER_REL, DRHdr);
369   emitCVDefRangeDirective(Ranges, BytePrefix);
370 }
371 
372 void MCStreamer::emitCVDefRangeDirective(
373     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
374     codeview::DefRangeSubfieldRegisterHeader DRHdr) {
375   SmallString<20> BytePrefix;
376   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_SUBFIELD_REGISTER,
377                        DRHdr);
378   emitCVDefRangeDirective(Ranges, BytePrefix);
379 }
380 
381 void MCStreamer::emitCVDefRangeDirective(
382     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
383     codeview::DefRangeRegisterHeader DRHdr) {
384   SmallString<20> BytePrefix;
385   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER, DRHdr);
386   emitCVDefRangeDirective(Ranges, BytePrefix);
387 }
388 
389 void MCStreamer::emitCVDefRangeDirective(
390     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
391     codeview::DefRangeFramePointerRelHeader DRHdr) {
392   SmallString<20> BytePrefix;
393   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_FRAMEPOINTER_REL,
394                        DRHdr);
395   emitCVDefRangeDirective(Ranges, BytePrefix);
396 }
397 
398 void MCStreamer::emitEHSymAttributes(const MCSymbol *Symbol,
399                                      MCSymbol *EHSymbol) {
400 }
401 
402 void MCStreamer::initSections(bool NoExecStack, const MCSubtargetInfo &STI) {
403   SwitchSection(getContext().getObjectFileInfo()->getTextSection());
404 }
405 
406 void MCStreamer::AssignFragment(MCSymbol *Symbol, MCFragment *Fragment) {
407   assert(Fragment);
408   Symbol->setFragment(Fragment);
409 
410   // As we emit symbols into a section, track the order so that they can
411   // be sorted upon later. Zero is reserved to mean 'unemitted'.
412   SymbolOrdering[Symbol] = 1 + SymbolOrdering.size();
413 }
414 
415 void MCStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
416   Symbol->redefineIfPossible();
417 
418   if (!Symbol->isUndefined() || Symbol->isVariable())
419     return getContext().reportError(Loc, "symbol '" + Twine(Symbol->getName()) +
420                                              "' is already defined");
421 
422   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
423   assert(getCurrentSectionOnly() && "Cannot emit before setting section!");
424   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
425   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
426 
427   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());
428 
429   MCTargetStreamer *TS = getTargetStreamer();
430   if (TS)
431     TS->emitLabel(Symbol);
432 }
433 
434 void MCStreamer::emitCFISections(bool EH, bool Debug) {}
435 
436 void MCStreamer::emitCFIStartProc(bool IsSimple, SMLoc Loc) {
437   if (hasUnfinishedDwarfFrameInfo())
438     return getContext().reportError(
439         Loc, "starting new .cfi frame before finishing the previous one");
440 
441   MCDwarfFrameInfo Frame;
442   Frame.IsSimple = IsSimple;
443   emitCFIStartProcImpl(Frame);
444 
445   const MCAsmInfo* MAI = Context.getAsmInfo();
446   if (MAI) {
447     for (const MCCFIInstruction& Inst : MAI->getInitialFrameState()) {
448       if (Inst.getOperation() == MCCFIInstruction::OpDefCfa ||
449           Inst.getOperation() == MCCFIInstruction::OpDefCfaRegister ||
450           Inst.getOperation() == MCCFIInstruction::OpLLVMDefAspaceCfa) {
451         Frame.CurrentCfaRegister = Inst.getRegister();
452       }
453     }
454   }
455 
456   DwarfFrameInfos.push_back(Frame);
457 }
458 
459 void MCStreamer::emitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
460 }
461 
462 void MCStreamer::emitCFIEndProc() {
463   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
464   if (!CurFrame)
465     return;
466   emitCFIEndProcImpl(*CurFrame);
467 }
468 
469 void MCStreamer::emitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
470   // Put a dummy non-null value in Frame.End to mark that this frame has been
471   // closed.
472   Frame.End = (MCSymbol *)1;
473 }
474 
475 MCSymbol *MCStreamer::emitCFILabel() {
476   // Return a dummy non-null value so that label fields appear filled in when
477   // generating textual assembly.
478   return (MCSymbol *)1;
479 }
480 
481 void MCStreamer::emitCFIDefCfa(int64_t Register, int64_t Offset) {
482   MCSymbol *Label = emitCFILabel();
483   MCCFIInstruction Instruction =
484       MCCFIInstruction::cfiDefCfa(Label, Register, Offset);
485   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
486   if (!CurFrame)
487     return;
488   CurFrame->Instructions.push_back(Instruction);
489   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
490 }
491 
492 void MCStreamer::emitCFIDefCfaOffset(int64_t Offset) {
493   MCSymbol *Label = emitCFILabel();
494   MCCFIInstruction Instruction =
495       MCCFIInstruction::cfiDefCfaOffset(Label, Offset);
496   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
497   if (!CurFrame)
498     return;
499   CurFrame->Instructions.push_back(Instruction);
500 }
501 
502 void MCStreamer::emitCFIAdjustCfaOffset(int64_t Adjustment) {
503   MCSymbol *Label = emitCFILabel();
504   MCCFIInstruction Instruction =
505     MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment);
506   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
507   if (!CurFrame)
508     return;
509   CurFrame->Instructions.push_back(Instruction);
510 }
511 
512 void MCStreamer::emitCFIDefCfaRegister(int64_t Register) {
513   MCSymbol *Label = emitCFILabel();
514   MCCFIInstruction Instruction =
515     MCCFIInstruction::createDefCfaRegister(Label, Register);
516   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
517   if (!CurFrame)
518     return;
519   CurFrame->Instructions.push_back(Instruction);
520   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
521 }
522 
523 void MCStreamer::emitCFILLVMDefAspaceCfa(int64_t Register, int64_t Offset,
524                                          int64_t AddressSpace) {
525   MCSymbol *Label = emitCFILabel();
526   MCCFIInstruction Instruction = MCCFIInstruction::createLLVMDefAspaceCfa(
527       Label, Register, Offset, AddressSpace);
528   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
529   if (!CurFrame)
530     return;
531   CurFrame->Instructions.push_back(Instruction);
532   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
533 }
534 
535 void MCStreamer::emitCFIOffset(int64_t Register, int64_t Offset) {
536   MCSymbol *Label = emitCFILabel();
537   MCCFIInstruction Instruction =
538     MCCFIInstruction::createOffset(Label, Register, Offset);
539   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
540   if (!CurFrame)
541     return;
542   CurFrame->Instructions.push_back(Instruction);
543 }
544 
545 void MCStreamer::emitCFIRelOffset(int64_t Register, int64_t Offset) {
546   MCSymbol *Label = emitCFILabel();
547   MCCFIInstruction Instruction =
548     MCCFIInstruction::createRelOffset(Label, Register, Offset);
549   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
550   if (!CurFrame)
551     return;
552   CurFrame->Instructions.push_back(Instruction);
553 }
554 
555 void MCStreamer::emitCFIPersonality(const MCSymbol *Sym,
556                                     unsigned Encoding) {
557   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
558   if (!CurFrame)
559     return;
560   CurFrame->Personality = Sym;
561   CurFrame->PersonalityEncoding = Encoding;
562 }
563 
564 void MCStreamer::emitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
565   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
566   if (!CurFrame)
567     return;
568   CurFrame->Lsda = Sym;
569   CurFrame->LsdaEncoding = Encoding;
570 }
571 
572 void MCStreamer::emitCFIRememberState() {
573   MCSymbol *Label = emitCFILabel();
574   MCCFIInstruction Instruction = MCCFIInstruction::createRememberState(Label);
575   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
576   if (!CurFrame)
577     return;
578   CurFrame->Instructions.push_back(Instruction);
579 }
580 
581 void MCStreamer::emitCFIRestoreState() {
582   // FIXME: Error if there is no matching cfi_remember_state.
583   MCSymbol *Label = emitCFILabel();
584   MCCFIInstruction Instruction = MCCFIInstruction::createRestoreState(Label);
585   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
586   if (!CurFrame)
587     return;
588   CurFrame->Instructions.push_back(Instruction);
589 }
590 
591 void MCStreamer::emitCFISameValue(int64_t Register) {
592   MCSymbol *Label = emitCFILabel();
593   MCCFIInstruction Instruction =
594     MCCFIInstruction::createSameValue(Label, Register);
595   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
596   if (!CurFrame)
597     return;
598   CurFrame->Instructions.push_back(Instruction);
599 }
600 
601 void MCStreamer::emitCFIRestore(int64_t Register) {
602   MCSymbol *Label = emitCFILabel();
603   MCCFIInstruction Instruction =
604     MCCFIInstruction::createRestore(Label, Register);
605   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
606   if (!CurFrame)
607     return;
608   CurFrame->Instructions.push_back(Instruction);
609 }
610 
611 void MCStreamer::emitCFIEscape(StringRef Values) {
612   MCSymbol *Label = emitCFILabel();
613   MCCFIInstruction Instruction = MCCFIInstruction::createEscape(Label, Values);
614   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
615   if (!CurFrame)
616     return;
617   CurFrame->Instructions.push_back(Instruction);
618 }
619 
620 void MCStreamer::emitCFIGnuArgsSize(int64_t Size) {
621   MCSymbol *Label = emitCFILabel();
622   MCCFIInstruction Instruction =
623     MCCFIInstruction::createGnuArgsSize(Label, Size);
624   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
625   if (!CurFrame)
626     return;
627   CurFrame->Instructions.push_back(Instruction);
628 }
629 
630 void MCStreamer::emitCFISignalFrame() {
631   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
632   if (!CurFrame)
633     return;
634   CurFrame->IsSignalFrame = true;
635 }
636 
637 void MCStreamer::emitCFIUndefined(int64_t Register) {
638   MCSymbol *Label = emitCFILabel();
639   MCCFIInstruction Instruction =
640     MCCFIInstruction::createUndefined(Label, Register);
641   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
642   if (!CurFrame)
643     return;
644   CurFrame->Instructions.push_back(Instruction);
645 }
646 
647 void MCStreamer::emitCFIRegister(int64_t Register1, int64_t Register2) {
648   MCSymbol *Label = emitCFILabel();
649   MCCFIInstruction Instruction =
650     MCCFIInstruction::createRegister(Label, Register1, Register2);
651   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
652   if (!CurFrame)
653     return;
654   CurFrame->Instructions.push_back(Instruction);
655 }
656 
657 void MCStreamer::emitCFIWindowSave() {
658   MCSymbol *Label = emitCFILabel();
659   MCCFIInstruction Instruction =
660     MCCFIInstruction::createWindowSave(Label);
661   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
662   if (!CurFrame)
663     return;
664   CurFrame->Instructions.push_back(Instruction);
665 }
666 
667 void MCStreamer::emitCFINegateRAState() {
668   MCSymbol *Label = emitCFILabel();
669   MCCFIInstruction Instruction = MCCFIInstruction::createNegateRAState(Label);
670   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
671   if (!CurFrame)
672     return;
673   CurFrame->Instructions.push_back(Instruction);
674 }
675 
676 void MCStreamer::emitCFIReturnColumn(int64_t Register) {
677   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
678   if (!CurFrame)
679     return;
680   CurFrame->RAReg = Register;
681 }
682 
683 WinEH::FrameInfo *MCStreamer::EnsureValidWinFrameInfo(SMLoc Loc) {
684   const MCAsmInfo *MAI = Context.getAsmInfo();
685   if (!MAI->usesWindowsCFI()) {
686     getContext().reportError(
687         Loc, ".seh_* directives are not supported on this target");
688     return nullptr;
689   }
690   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End) {
691     getContext().reportError(
692         Loc, ".seh_ directive must appear within an active frame");
693     return nullptr;
694   }
695   return CurrentWinFrameInfo;
696 }
697 
698 void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc) {
699   const MCAsmInfo *MAI = Context.getAsmInfo();
700   if (!MAI->usesWindowsCFI())
701     return getContext().reportError(
702         Loc, ".seh_* directives are not supported on this target");
703   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
704     getContext().reportError(
705         Loc, "Starting a function before ending the previous one!");
706 
707   MCSymbol *StartProc = emitCFILabel();
708 
709   CurrentProcWinFrameInfoStartIndex = WinFrameInfos.size();
710   WinFrameInfos.emplace_back(
711       std::make_unique<WinEH::FrameInfo>(Symbol, StartProc));
712   CurrentWinFrameInfo = WinFrameInfos.back().get();
713   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
714 }
715 
716 void MCStreamer::EmitWinCFIEndProc(SMLoc Loc) {
717   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
718   if (!CurFrame)
719     return;
720   if (CurFrame->ChainedParent)
721     getContext().reportError(Loc, "Not all chained regions terminated!");
722 
723   MCSymbol *Label = emitCFILabel();
724   CurFrame->End = Label;
725   if (!CurFrame->FuncletOrFuncEnd)
726     CurFrame->FuncletOrFuncEnd = CurFrame->End;
727 
728   for (size_t I = CurrentProcWinFrameInfoStartIndex, E = WinFrameInfos.size();
729        I != E; ++I)
730     EmitWindowsUnwindTables(WinFrameInfos[I].get());
731   SwitchSection(CurFrame->TextSection);
732 }
733 
734 void MCStreamer::EmitWinCFIFuncletOrFuncEnd(SMLoc Loc) {
735   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
736   if (!CurFrame)
737     return;
738   if (CurFrame->ChainedParent)
739     getContext().reportError(Loc, "Not all chained regions terminated!");
740 
741   MCSymbol *Label = emitCFILabel();
742   CurFrame->FuncletOrFuncEnd = Label;
743 }
744 
745 void MCStreamer::EmitWinCFIStartChained(SMLoc Loc) {
746   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
747   if (!CurFrame)
748     return;
749 
750   MCSymbol *StartProc = emitCFILabel();
751 
752   WinFrameInfos.emplace_back(std::make_unique<WinEH::FrameInfo>(
753       CurFrame->Function, StartProc, CurFrame));
754   CurrentWinFrameInfo = WinFrameInfos.back().get();
755   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
756 }
757 
758 void MCStreamer::EmitWinCFIEndChained(SMLoc Loc) {
759   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
760   if (!CurFrame)
761     return;
762   if (!CurFrame->ChainedParent)
763     return getContext().reportError(
764         Loc, "End of a chained region outside a chained region!");
765 
766   MCSymbol *Label = emitCFILabel();
767 
768   CurFrame->End = Label;
769   CurrentWinFrameInfo = const_cast<WinEH::FrameInfo *>(CurFrame->ChainedParent);
770 }
771 
772 void MCStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
773                                   SMLoc Loc) {
774   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
775   if (!CurFrame)
776     return;
777   if (CurFrame->ChainedParent)
778     return getContext().reportError(
779         Loc, "Chained unwind areas can't have handlers!");
780   CurFrame->ExceptionHandler = Sym;
781   if (!Except && !Unwind)
782     getContext().reportError(Loc, "Don't know what kind of handler this is!");
783   if (Unwind)
784     CurFrame->HandlesUnwind = true;
785   if (Except)
786     CurFrame->HandlesExceptions = true;
787 }
788 
789 void MCStreamer::EmitWinEHHandlerData(SMLoc Loc) {
790   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
791   if (!CurFrame)
792     return;
793   if (CurFrame->ChainedParent)
794     getContext().reportError(Loc, "Chained unwind areas can't have handlers!");
795 }
796 
797 void MCStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
798                                     const MCSymbolRefExpr *To, uint64_t Count) {
799 }
800 
801 static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
802                                    MCSection *MainCFISec,
803                                    const MCSection *TextSec) {
804   // If this is the main .text section, use the main unwind info section.
805   if (TextSec == Context.getObjectFileInfo()->getTextSection())
806     return MainCFISec;
807 
808   const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
809   auto *MainCFISecCOFF = cast<MCSectionCOFF>(MainCFISec);
810   unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
811 
812   // If this section is COMDAT, this unwind section should be COMDAT associative
813   // with its group.
814   const MCSymbol *KeySym = nullptr;
815   if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
816     KeySym = TextSecCOFF->getCOMDATSymbol();
817 
818     // In a GNU environment, we can't use associative comdats. Instead, do what
819     // GCC does, which is to make plain comdat selectany section named like
820     // ".[px]data$_Z3foov".
821     if (!Context.getAsmInfo()->hasCOFFAssociativeComdats()) {
822       std::string SectionName = (MainCFISecCOFF->getName() + "$" +
823                                  TextSecCOFF->getName().split('$').second)
824                                     .str();
825       return Context.getCOFFSection(
826           SectionName,
827           MainCFISecCOFF->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT,
828           MainCFISecCOFF->getKind(), "", COFF::IMAGE_COMDAT_SELECT_ANY);
829     }
830   }
831 
832   return Context.getAssociativeCOFFSection(MainCFISecCOFF, KeySym, UniqueID);
833 }
834 
835 MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
836   return getWinCFISection(getContext(), &NextWinCFIID,
837                           getContext().getObjectFileInfo()->getPDataSection(),
838                           TextSec);
839 }
840 
841 MCSection *MCStreamer::getAssociatedXDataSection(const MCSection *TextSec) {
842   return getWinCFISection(getContext(), &NextWinCFIID,
843                           getContext().getObjectFileInfo()->getXDataSection(),
844                           TextSec);
845 }
846 
847 void MCStreamer::emitSyntaxDirective() {}
848 
849 static unsigned encodeSEHRegNum(MCContext &Ctx, MCRegister Reg) {
850   return Ctx.getRegisterInfo()->getSEHRegNum(Reg);
851 }
852 
853 void MCStreamer::EmitWinCFIPushReg(MCRegister Register, SMLoc Loc) {
854   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
855   if (!CurFrame)
856     return;
857 
858   MCSymbol *Label = emitCFILabel();
859 
860   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(
861       Label, encodeSEHRegNum(Context, Register));
862   CurFrame->Instructions.push_back(Inst);
863 }
864 
865 void MCStreamer::EmitWinCFISetFrame(MCRegister Register, unsigned Offset,
866                                     SMLoc Loc) {
867   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
868   if (!CurFrame)
869     return;
870   if (CurFrame->LastFrameInst >= 0)
871     return getContext().reportError(
872         Loc, "frame register and offset can be set at most once");
873   if (Offset & 0x0F)
874     return getContext().reportError(Loc, "offset is not a multiple of 16");
875   if (Offset > 240)
876     return getContext().reportError(
877         Loc, "frame offset must be less than or equal to 240");
878 
879   MCSymbol *Label = emitCFILabel();
880 
881   WinEH::Instruction Inst = Win64EH::Instruction::SetFPReg(
882       Label, encodeSEHRegNum(getContext(), Register), Offset);
883   CurFrame->LastFrameInst = CurFrame->Instructions.size();
884   CurFrame->Instructions.push_back(Inst);
885 }
886 
887 void MCStreamer::EmitWinCFIAllocStack(unsigned Size, SMLoc Loc) {
888   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
889   if (!CurFrame)
890     return;
891   if (Size == 0)
892     return getContext().reportError(Loc,
893                                     "stack allocation size must be non-zero");
894   if (Size & 7)
895     return getContext().reportError(
896         Loc, "stack allocation size is not a multiple of 8");
897 
898   MCSymbol *Label = emitCFILabel();
899 
900   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
901   CurFrame->Instructions.push_back(Inst);
902 }
903 
904 void MCStreamer::EmitWinCFISaveReg(MCRegister Register, unsigned Offset,
905                                    SMLoc Loc) {
906   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
907   if (!CurFrame)
908     return;
909 
910   if (Offset & 7)
911     return getContext().reportError(
912         Loc, "register save offset is not 8 byte aligned");
913 
914   MCSymbol *Label = emitCFILabel();
915 
916   WinEH::Instruction Inst = Win64EH::Instruction::SaveNonVol(
917       Label, encodeSEHRegNum(Context, Register), Offset);
918   CurFrame->Instructions.push_back(Inst);
919 }
920 
921 void MCStreamer::EmitWinCFISaveXMM(MCRegister Register, unsigned Offset,
922                                    SMLoc Loc) {
923   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
924   if (!CurFrame)
925     return;
926   if (Offset & 0x0F)
927     return getContext().reportError(Loc, "offset is not a multiple of 16");
928 
929   MCSymbol *Label = emitCFILabel();
930 
931   WinEH::Instruction Inst = Win64EH::Instruction::SaveXMM(
932       Label, encodeSEHRegNum(Context, Register), Offset);
933   CurFrame->Instructions.push_back(Inst);
934 }
935 
936 void MCStreamer::EmitWinCFIPushFrame(bool Code, SMLoc Loc) {
937   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
938   if (!CurFrame)
939     return;
940   if (!CurFrame->Instructions.empty())
941     return getContext().reportError(
942         Loc, "If present, PushMachFrame must be the first UOP");
943 
944   MCSymbol *Label = emitCFILabel();
945 
946   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
947   CurFrame->Instructions.push_back(Inst);
948 }
949 
950 void MCStreamer::EmitWinCFIEndProlog(SMLoc Loc) {
951   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
952   if (!CurFrame)
953     return;
954 
955   MCSymbol *Label = emitCFILabel();
956 
957   CurFrame->PrologEnd = Label;
958 }
959 
960 void MCStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {}
961 
962 void MCStreamer::EmitCOFFSymbolIndex(MCSymbol const *Symbol) {}
963 
964 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {}
965 
966 void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {}
967 
968 void MCStreamer::EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) {}
969 
970 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
971 /// the specified string in the output .s file.  This capability is
972 /// indicated by the hasRawTextSupport() predicate.
973 void MCStreamer::emitRawTextImpl(StringRef String) {
974   // This is not llvm_unreachable for the sake of out of tree backend
975   // developers who may not have assembly streamers and should serve as a
976   // reminder to not accidentally call EmitRawText in the absence of such.
977   report_fatal_error("EmitRawText called on an MCStreamer that doesn't support "
978                      "it (target backend is likely missing an AsmStreamer "
979                      "implementation)");
980 }
981 
982 void MCStreamer::emitRawText(const Twine &T) {
983   SmallString<128> Str;
984   emitRawTextImpl(T.toStringRef(Str));
985 }
986 
987 void MCStreamer::EmitWindowsUnwindTables() {
988 }
989 
990 void MCStreamer::EmitWindowsUnwindTables(WinEH::FrameInfo *Frame) {
991 }
992 
993 void MCStreamer::Finish(SMLoc EndLoc) {
994   if ((!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End) ||
995       (!WinFrameInfos.empty() && !WinFrameInfos.back()->End)) {
996     getContext().reportError(EndLoc, "Unfinished frame!");
997     return;
998   }
999 
1000   MCTargetStreamer *TS = getTargetStreamer();
1001   if (TS)
1002     TS->finish();
1003 
1004   finishImpl();
1005 }
1006 
1007 void MCStreamer::maybeEmitDwarf64Mark() {
1008   if (Context.getDwarfFormat() != dwarf::DWARF64)
1009     return;
1010   AddComment("DWARF64 Mark");
1011   emitInt32(dwarf::DW_LENGTH_DWARF64);
1012 }
1013 
1014 void MCStreamer::emitDwarfUnitLength(uint64_t Length, const Twine &Comment) {
1015   assert(Context.getDwarfFormat() == dwarf::DWARF64 ||
1016          Length <= dwarf::DW_LENGTH_lo_reserved);
1017   maybeEmitDwarf64Mark();
1018   AddComment(Comment);
1019   emitIntValue(Length, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1020 }
1021 
1022 MCSymbol *MCStreamer::emitDwarfUnitLength(const Twine &Prefix,
1023                                           const Twine &Comment) {
1024   maybeEmitDwarf64Mark();
1025   AddComment(Comment);
1026   MCSymbol *Lo = Context.createTempSymbol(Prefix + "_start");
1027   MCSymbol *Hi = Context.createTempSymbol(Prefix + "_end");
1028 
1029   emitAbsoluteSymbolDiff(
1030       Hi, Lo, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1031   // emit the begin symbol after we generate the length field.
1032   emitLabel(Lo);
1033   // Return the Hi symbol to the caller.
1034   return Hi;
1035 }
1036 
1037 void MCStreamer::emitDwarfLineStartLabel(MCSymbol *StartSym) {
1038   // Set the value of the symbol, as we are at the start of the line table.
1039   emitLabel(StartSym);
1040 }
1041 
1042 void MCStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
1043   visitUsedExpr(*Value);
1044   Symbol->setVariableValue(Value);
1045 
1046   MCTargetStreamer *TS = getTargetStreamer();
1047   if (TS)
1048     TS->emitAssignment(Symbol, Value);
1049 }
1050 
1051 void MCTargetStreamer::prettyPrintAsm(MCInstPrinter &InstPrinter,
1052                                       uint64_t Address, const MCInst &Inst,
1053                                       const MCSubtargetInfo &STI,
1054                                       raw_ostream &OS) {
1055   InstPrinter.printInst(&Inst, Address, "", STI, OS);
1056 }
1057 
1058 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
1059 }
1060 
1061 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
1062   switch (Expr.getKind()) {
1063   case MCExpr::Target:
1064     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
1065     break;
1066 
1067   case MCExpr::Constant:
1068     break;
1069 
1070   case MCExpr::Binary: {
1071     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
1072     visitUsedExpr(*BE.getLHS());
1073     visitUsedExpr(*BE.getRHS());
1074     break;
1075   }
1076 
1077   case MCExpr::SymbolRef:
1078     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
1079     break;
1080 
1081   case MCExpr::Unary:
1082     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
1083     break;
1084   }
1085 }
1086 
1087 void MCStreamer::emitInstruction(const MCInst &Inst, const MCSubtargetInfo &) {
1088   // Scan for values.
1089   for (unsigned i = Inst.getNumOperands(); i--;)
1090     if (Inst.getOperand(i).isExpr())
1091       visitUsedExpr(*Inst.getOperand(i).getExpr());
1092 }
1093 
1094 void MCStreamer::emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
1095                                  uint64_t Attr,
1096                                  const MCPseudoProbeInlineStack &InlineStack) {
1097   auto &Context = getContext();
1098 
1099   // Create a symbol at in the current section for use in the probe.
1100   MCSymbol *ProbeSym = Context.createTempSymbol();
1101 
1102   // Set the value of the symbol to use for the MCPseudoProbe.
1103   emitLabel(ProbeSym);
1104 
1105   // Create a (local) probe entry with the symbol.
1106   MCPseudoProbe Probe(ProbeSym, Guid, Index, Type, Attr);
1107 
1108   // Add the probe entry to this section's entries.
1109   Context.getMCPseudoProbeTable().getProbeSections().addPseudoProbe(
1110       getCurrentSectionOnly(), Probe, InlineStack);
1111 }
1112 
1113 void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
1114                                         unsigned Size) {
1115   // Get the Hi-Lo expression.
1116   const MCExpr *Diff =
1117       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1118                               MCSymbolRefExpr::create(Lo, Context), Context);
1119 
1120   const MCAsmInfo *MAI = Context.getAsmInfo();
1121   if (!MAI->doesSetDirectiveSuppressReloc()) {
1122     emitValue(Diff, Size);
1123     return;
1124   }
1125 
1126   // Otherwise, emit with .set (aka assignment).
1127   MCSymbol *SetLabel = Context.createTempSymbol("set");
1128   emitAssignment(SetLabel, Diff);
1129   emitSymbolValue(SetLabel, Size);
1130 }
1131 
1132 void MCStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
1133                                                  const MCSymbol *Lo) {
1134   // Get the Hi-Lo expression.
1135   const MCExpr *Diff =
1136       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1137                               MCSymbolRefExpr::create(Lo, Context), Context);
1138 
1139   emitULEB128Value(Diff);
1140 }
1141 
1142 void MCStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {}
1143 void MCStreamer::emitThumbFunc(MCSymbol *Func) {}
1144 void MCStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
1145 void MCStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
1146   llvm_unreachable("this directive only supported on COFF targets");
1147 }
1148 void MCStreamer::EndCOFFSymbolDef() {
1149   llvm_unreachable("this directive only supported on COFF targets");
1150 }
1151 void MCStreamer::emitFileDirective(StringRef Filename) {}
1152 void MCStreamer::emitFileDirective(StringRef Filename, StringRef CompilerVerion,
1153                                    StringRef TimeStamp, StringRef Description) {
1154 }
1155 void MCStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
1156   llvm_unreachable("this directive only supported on COFF targets");
1157 }
1158 void MCStreamer::EmitCOFFSymbolType(int Type) {
1159   llvm_unreachable("this directive only supported on COFF targets");
1160 }
1161 void MCStreamer::emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
1162                                             MCSymbol *CsectSym,
1163                                             unsigned ByteAlign) {
1164   llvm_unreachable("this directive only supported on XCOFF targets");
1165 }
1166 
1167 void MCStreamer::emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol,
1168                                                       MCSymbolAttr Linkage,
1169                                                       MCSymbolAttr Visibility) {
1170   llvm_unreachable("emitXCOFFSymbolLinkageWithVisibility is only supported on "
1171                    "XCOFF targets");
1172 }
1173 
1174 void MCStreamer::emitXCOFFRenameDirective(const MCSymbol *Name,
1175                                           StringRef Rename) {
1176   llvm_unreachable("emitXCOFFRenameDirective is only supported on "
1177                    "XCOFF targets");
1178 }
1179 
1180 void MCStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
1181 void MCStreamer::emitELFSymverDirective(const MCSymbol *OriginalSym,
1182                                         StringRef Name, bool KeepOriginalSym) {}
1183 void MCStreamer::emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
1184                                        unsigned ByteAlignment) {}
1185 void MCStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
1186                                 uint64_t Size, unsigned ByteAlignment) {}
1187 void MCStreamer::changeSection(MCSection *, const MCExpr *) {}
1188 void MCStreamer::emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
1189 void MCStreamer::emitBytes(StringRef Data) {}
1190 void MCStreamer::emitBinaryData(StringRef Data) { emitBytes(Data); }
1191 void MCStreamer::emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) {
1192   visitUsedExpr(*Value);
1193 }
1194 void MCStreamer::emitULEB128Value(const MCExpr *Value) {}
1195 void MCStreamer::emitSLEB128Value(const MCExpr *Value) {}
1196 void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc Loc) {}
1197 void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
1198                           SMLoc Loc) {}
1199 void MCStreamer::emitValueToAlignment(unsigned ByteAlignment, int64_t Value,
1200                                       unsigned ValueSize,
1201                                       unsigned MaxBytesToEmit) {}
1202 void MCStreamer::emitCodeAlignment(unsigned ByteAlignment,
1203                                    const MCSubtargetInfo *STI,
1204                                    unsigned MaxBytesToEmit) {}
1205 void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value,
1206                                    SMLoc Loc) {}
1207 void MCStreamer::emitBundleAlignMode(unsigned AlignPow2) {}
1208 void MCStreamer::emitBundleLock(bool AlignToEnd) {}
1209 void MCStreamer::finishImpl() {}
1210 void MCStreamer::emitBundleUnlock() {}
1211 
1212 void MCStreamer::SwitchSection(MCSection *Section, const MCExpr *Subsection) {
1213   assert(Section && "Cannot switch to a null section!");
1214   MCSectionSubPair curSection = SectionStack.back().first;
1215   SectionStack.back().second = curSection;
1216   if (MCSectionSubPair(Section, Subsection) != curSection) {
1217     changeSection(Section, Subsection);
1218     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
1219     assert(!Section->hasEnded() && "Section already ended");
1220     MCSymbol *Sym = Section->getBeginSymbol();
1221     if (Sym && !Sym->isInSection())
1222       emitLabel(Sym);
1223   }
1224 }
1225 
1226 MCSymbol *MCStreamer::endSection(MCSection *Section) {
1227   // TODO: keep track of the last subsection so that this symbol appears in the
1228   // correct place.
1229   MCSymbol *Sym = Section->getEndSymbol(Context);
1230   if (Sym->isInSection())
1231     return Sym;
1232 
1233   SwitchSection(Section);
1234   emitLabel(Sym);
1235   return Sym;
1236 }
1237 
1238 static VersionTuple
1239 targetVersionOrMinimumSupportedOSVersion(const Triple &Target,
1240                                          VersionTuple TargetVersion) {
1241   VersionTuple Min = Target.getMinimumSupportedOSVersion();
1242   return !Min.empty() && Min > TargetVersion ? Min : TargetVersion;
1243 }
1244 
1245 static MCVersionMinType
1246 getMachoVersionMinLoadCommandType(const Triple &Target) {
1247   assert(Target.isOSDarwin() && "expected a darwin OS");
1248   switch (Target.getOS()) {
1249   case Triple::MacOSX:
1250   case Triple::Darwin:
1251     return MCVM_OSXVersionMin;
1252   case Triple::IOS:
1253     assert(!Target.isMacCatalystEnvironment() &&
1254            "mac Catalyst should use LC_BUILD_VERSION");
1255     return MCVM_IOSVersionMin;
1256   case Triple::TvOS:
1257     return MCVM_TvOSVersionMin;
1258   case Triple::WatchOS:
1259     return MCVM_WatchOSVersionMin;
1260   default:
1261     break;
1262   }
1263   llvm_unreachable("unexpected OS type");
1264 }
1265 
1266 static VersionTuple getMachoBuildVersionSupportedOS(const Triple &Target) {
1267   assert(Target.isOSDarwin() && "expected a darwin OS");
1268   switch (Target.getOS()) {
1269   case Triple::MacOSX:
1270   case Triple::Darwin:
1271     return VersionTuple(10, 14);
1272   case Triple::IOS:
1273     // Mac Catalyst always uses the build version load command.
1274     if (Target.isMacCatalystEnvironment())
1275       return VersionTuple();
1276     LLVM_FALLTHROUGH;
1277   case Triple::TvOS:
1278     return VersionTuple(12);
1279   case Triple::WatchOS:
1280     return VersionTuple(5);
1281   default:
1282     break;
1283   }
1284   llvm_unreachable("unexpected OS type");
1285 }
1286 
1287 static MachO::PlatformType
1288 getMachoBuildVersionPlatformType(const Triple &Target) {
1289   assert(Target.isOSDarwin() && "expected a darwin OS");
1290   switch (Target.getOS()) {
1291   case Triple::MacOSX:
1292   case Triple::Darwin:
1293     return MachO::PLATFORM_MACOS;
1294   case Triple::IOS:
1295     if (Target.isMacCatalystEnvironment())
1296       return MachO::PLATFORM_MACCATALYST;
1297     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_IOSSIMULATOR
1298                                            : MachO::PLATFORM_IOS;
1299   case Triple::TvOS:
1300     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_TVOSSIMULATOR
1301                                            : MachO::PLATFORM_TVOS;
1302   case Triple::WatchOS:
1303     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_WATCHOSSIMULATOR
1304                                            : MachO::PLATFORM_WATCHOS;
1305   default:
1306     break;
1307   }
1308   llvm_unreachable("unexpected OS type");
1309 }
1310 
1311 void MCStreamer::emitVersionForTarget(const Triple &Target,
1312                                       const VersionTuple &SDKVersion) {
1313   if (!Target.isOSBinFormatMachO() || !Target.isOSDarwin())
1314     return;
1315   // Do we even know the version?
1316   if (Target.getOSMajorVersion() == 0)
1317     return;
1318 
1319   unsigned Major = 0;
1320   unsigned Minor = 0;
1321   unsigned Update = 0;
1322   switch (Target.getOS()) {
1323   case Triple::MacOSX:
1324   case Triple::Darwin:
1325     Target.getMacOSXVersion(Major, Minor, Update);
1326     break;
1327   case Triple::IOS:
1328   case Triple::TvOS:
1329     Target.getiOSVersion(Major, Minor, Update);
1330     break;
1331   case Triple::WatchOS:
1332     Target.getWatchOSVersion(Major, Minor, Update);
1333     break;
1334   default:
1335     llvm_unreachable("unexpected OS type");
1336   }
1337   assert(Major != 0 && "A non-zero major version is expected");
1338   auto LinkedTargetVersion = targetVersionOrMinimumSupportedOSVersion(
1339       Target, VersionTuple(Major, Minor, Update));
1340   auto BuildVersionOSVersion = getMachoBuildVersionSupportedOS(Target);
1341   if (BuildVersionOSVersion.empty() ||
1342       LinkedTargetVersion >= BuildVersionOSVersion)
1343     return emitBuildVersion(getMachoBuildVersionPlatformType(Target),
1344                             LinkedTargetVersion.getMajor(),
1345                             *LinkedTargetVersion.getMinor(),
1346                             *LinkedTargetVersion.getSubminor(), SDKVersion);
1347 
1348   emitVersionMin(getMachoVersionMinLoadCommandType(Target),
1349                  LinkedTargetVersion.getMajor(),
1350                  *LinkedTargetVersion.getMinor(),
1351                  *LinkedTargetVersion.getSubminor(), SDKVersion);
1352 }
1353