xref: /freebsd/contrib/llvm-project/llvm/lib/MC/MCStreamer.cpp (revision b64c5a0ace59af62eff52bfe110a521dc73c937b) 
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, uint32_t 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) {
96   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
97 }
98 
99 MCStreamer::~MCStreamer() = default;
100 
101 void MCStreamer::reset() {
102   DwarfFrameInfos.clear();
103   CurrentWinFrameInfo = nullptr;
104   WinFrameInfos.clear();
105   SectionStack.clear();
106   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
107   CurFrag = nullptr;
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, &Context) : 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 ? llvm::endianness::little : llvm::endianness::big);
140   unsigned Index = IsLittleEndian ? 0 : 8 - Size;
141   emitBytes(StringRef(reinterpret_cast<char *>(&Swapped) + Index, Size));
142 }
143 void MCStreamer::emitIntValue(const 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 unsigned 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   return Tmp.size();
167 }
168 
169 /// EmitSLEB128IntValue - Special case of EmitSLEB128Value that avoids the
170 /// client having to pass in a MCExpr for constant integers.
171 unsigned MCStreamer::emitSLEB128IntValue(int64_t Value) {
172   SmallString<128> Tmp;
173   raw_svector_ostream OSE(Tmp);
174   encodeSLEB128(Value, OSE);
175   emitBytes(OSE.str());
176   return Tmp.size();
177 }
178 
179 void MCStreamer::emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc) {
180   emitValueImpl(Value, Size, Loc);
181 }
182 
183 void MCStreamer::emitSymbolValue(const MCSymbol *Sym, unsigned Size,
184                                  bool IsSectionRelative) {
185   assert((!IsSectionRelative || Size == 4) &&
186          "SectionRelative value requires 4-bytes");
187 
188   if (!IsSectionRelative)
189     emitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
190   else
191     emitCOFFSecRel32(Sym, /*Offset=*/0);
192 }
193 
194 void MCStreamer::emitDTPRel64Value(const MCExpr *Value) {
195   report_fatal_error("unsupported directive in streamer");
196 }
197 
198 void MCStreamer::emitDTPRel32Value(const MCExpr *Value) {
199   report_fatal_error("unsupported directive in streamer");
200 }
201 
202 void MCStreamer::emitTPRel64Value(const MCExpr *Value) {
203   report_fatal_error("unsupported directive in streamer");
204 }
205 
206 void MCStreamer::emitTPRel32Value(const MCExpr *Value) {
207   report_fatal_error("unsupported directive in streamer");
208 }
209 
210 void MCStreamer::emitGPRel64Value(const MCExpr *Value) {
211   report_fatal_error("unsupported directive in streamer");
212 }
213 
214 void MCStreamer::emitGPRel32Value(const MCExpr *Value) {
215   report_fatal_error("unsupported directive in streamer");
216 }
217 
218 /// Emit NumBytes bytes worth of the value specified by FillValue.
219 /// This implements directives such as '.space'.
220 void MCStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
221   if (NumBytes)
222     emitFill(*MCConstantExpr::create(NumBytes, getContext()), FillValue);
223 }
224 
225 void llvm::MCStreamer::emitNops(int64_t NumBytes, int64_t ControlledNopLen,
226                                 llvm::SMLoc, const MCSubtargetInfo& STI) {}
227 
228 /// The implementation in this class just redirects to emitFill.
229 void MCStreamer::emitZeros(uint64_t NumBytes) { emitFill(NumBytes, 0); }
230 
231 Expected<unsigned> MCStreamer::tryEmitDwarfFileDirective(
232     unsigned FileNo, StringRef Directory, StringRef Filename,
233     std::optional<MD5::MD5Result> Checksum, std::optional<StringRef> Source,
234     unsigned CUID) {
235   return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
236                                    Source, CUID);
237 }
238 
239 void MCStreamer::emitDwarfFile0Directive(StringRef Directory,
240                                          StringRef Filename,
241                                          std::optional<MD5::MD5Result> Checksum,
242                                          std::optional<StringRef> Source,
243                                          unsigned CUID) {
244   getContext().setMCLineTableRootFile(CUID, Directory, Filename, Checksum,
245                                       Source);
246 }
247 
248 void MCStreamer::emitCFIBKeyFrame() {
249   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
250   if (!CurFrame)
251     return;
252   CurFrame->IsBKeyFrame = true;
253 }
254 
255 void MCStreamer::emitCFIMTETaggedFrame() {
256   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
257   if (!CurFrame)
258     return;
259   CurFrame->IsMTETaggedFrame = true;
260 }
261 
262 void MCStreamer::emitDwarfLocDirective(unsigned FileNo, unsigned Line,
263                                        unsigned Column, unsigned Flags,
264                                        unsigned Isa, unsigned Discriminator,
265                                        StringRef FileName) {
266   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
267                                   Discriminator);
268 }
269 
270 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
271   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
272   if (!Table.getLabel()) {
273     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
274     Table.setLabel(
275         Context.getOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
276   }
277   return Table.getLabel();
278 }
279 
280 bool MCStreamer::hasUnfinishedDwarfFrameInfo() {
281   return !FrameInfoStack.empty();
282 }
283 
284 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
285   if (!hasUnfinishedDwarfFrameInfo()) {
286     getContext().reportError(getStartTokLoc(),
287                              "this directive must appear between "
288                              ".cfi_startproc and .cfi_endproc directives");
289     return nullptr;
290   }
291   return &DwarfFrameInfos[FrameInfoStack.back().first];
292 }
293 
294 bool MCStreamer::emitCVFileDirective(unsigned FileNo, StringRef Filename,
295                                      ArrayRef<uint8_t> Checksum,
296                                      unsigned ChecksumKind) {
297   return getContext().getCVContext().addFile(*this, FileNo, Filename, Checksum,
298                                              ChecksumKind);
299 }
300 
301 bool MCStreamer::emitCVFuncIdDirective(unsigned FunctionId) {
302   return getContext().getCVContext().recordFunctionId(FunctionId);
303 }
304 
305 bool MCStreamer::emitCVInlineSiteIdDirective(unsigned FunctionId,
306                                              unsigned IAFunc, unsigned IAFile,
307                                              unsigned IALine, unsigned IACol,
308                                              SMLoc Loc) {
309   if (getContext().getCVContext().getCVFunctionInfo(IAFunc) == nullptr) {
310     getContext().reportError(Loc, "parent function id not introduced by "
311                                   ".cv_func_id or .cv_inline_site_id");
312     return true;
313   }
314 
315   return getContext().getCVContext().recordInlinedCallSiteId(
316       FunctionId, IAFunc, IAFile, IALine, IACol);
317 }
318 
319 void MCStreamer::emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
320                                     unsigned Line, unsigned Column,
321                                     bool PrologueEnd, bool IsStmt,
322                                     StringRef FileName, SMLoc Loc) {}
323 
324 bool MCStreamer::checkCVLocSection(unsigned FuncId, unsigned FileNo,
325                                    SMLoc Loc) {
326   CodeViewContext &CVC = getContext().getCVContext();
327   MCCVFunctionInfo *FI = CVC.getCVFunctionInfo(FuncId);
328   if (!FI) {
329     getContext().reportError(
330         Loc, "function id not introduced by .cv_func_id or .cv_inline_site_id");
331     return false;
332   }
333 
334   // Track the section
335   if (FI->Section == nullptr)
336     FI->Section = getCurrentSectionOnly();
337   else if (FI->Section != getCurrentSectionOnly()) {
338     getContext().reportError(
339         Loc,
340         "all .cv_loc directives for a function must be in the same section");
341     return false;
342   }
343   return true;
344 }
345 
346 void MCStreamer::emitCVLinetableDirective(unsigned FunctionId,
347                                           const MCSymbol *Begin,
348                                           const MCSymbol *End) {}
349 
350 void MCStreamer::emitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
351                                                 unsigned SourceFileId,
352                                                 unsigned SourceLineNum,
353                                                 const MCSymbol *FnStartSym,
354                                                 const MCSymbol *FnEndSym) {}
355 
356 /// Only call this on endian-specific types like ulittle16_t and little32_t, or
357 /// structs composed of them.
358 template <typename T>
359 static void copyBytesForDefRange(SmallString<20> &BytePrefix,
360                                  codeview::SymbolKind SymKind,
361                                  const T &DefRangeHeader) {
362   BytePrefix.resize(2 + sizeof(T));
363   codeview::ulittle16_t SymKindLE = codeview::ulittle16_t(SymKind);
364   memcpy(&BytePrefix[0], &SymKindLE, 2);
365   memcpy(&BytePrefix[2], &DefRangeHeader, sizeof(T));
366 }
367 
368 void MCStreamer::emitCVDefRangeDirective(
369     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
370     StringRef FixedSizePortion) {}
371 
372 void MCStreamer::emitCVDefRangeDirective(
373     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
374     codeview::DefRangeRegisterRelHeader DRHdr) {
375   SmallString<20> BytePrefix;
376   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER_REL, DRHdr);
377   emitCVDefRangeDirective(Ranges, BytePrefix);
378 }
379 
380 void MCStreamer::emitCVDefRangeDirective(
381     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
382     codeview::DefRangeSubfieldRegisterHeader DRHdr) {
383   SmallString<20> BytePrefix;
384   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_SUBFIELD_REGISTER,
385                        DRHdr);
386   emitCVDefRangeDirective(Ranges, BytePrefix);
387 }
388 
389 void MCStreamer::emitCVDefRangeDirective(
390     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
391     codeview::DefRangeRegisterHeader DRHdr) {
392   SmallString<20> BytePrefix;
393   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_REGISTER, DRHdr);
394   emitCVDefRangeDirective(Ranges, BytePrefix);
395 }
396 
397 void MCStreamer::emitCVDefRangeDirective(
398     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
399     codeview::DefRangeFramePointerRelHeader DRHdr) {
400   SmallString<20> BytePrefix;
401   copyBytesForDefRange(BytePrefix, codeview::S_DEFRANGE_FRAMEPOINTER_REL,
402                        DRHdr);
403   emitCVDefRangeDirective(Ranges, BytePrefix);
404 }
405 
406 void MCStreamer::emitEHSymAttributes(const MCSymbol *Symbol,
407                                      MCSymbol *EHSymbol) {
408 }
409 
410 void MCStreamer::initSections(bool NoExecStack, const MCSubtargetInfo &STI) {
411   switchSection(getContext().getObjectFileInfo()->getTextSection());
412 }
413 
414 void MCStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
415   Symbol->redefineIfPossible();
416 
417   if (!Symbol->isUndefined() || Symbol->isVariable())
418     return getContext().reportError(Loc, "symbol '" + Twine(Symbol->getName()) +
419                                              "' is already defined");
420 
421   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
422   assert(getCurrentSectionOnly() && "Cannot emit before setting section!");
423   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
424   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
425 
426   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());
427 
428   MCTargetStreamer *TS = getTargetStreamer();
429   if (TS)
430     TS->emitLabel(Symbol);
431 }
432 
433 void MCStreamer::emitConditionalAssignment(MCSymbol *Symbol,
434                                            const MCExpr *Value) {}
435 
436 void MCStreamer::emitCFISections(bool EH, bool Debug) {}
437 
438 void MCStreamer::emitCFIStartProc(bool IsSimple, SMLoc Loc) {
439   if (!FrameInfoStack.empty() &&
440       getCurrentSectionOnly() == FrameInfoStack.back().second)
441     return getContext().reportError(
442         Loc, "starting new .cfi frame before finishing the previous one");
443 
444   MCDwarfFrameInfo Frame;
445   Frame.IsSimple = IsSimple;
446   emitCFIStartProcImpl(Frame);
447 
448   const MCAsmInfo* MAI = Context.getAsmInfo();
449   if (MAI) {
450     for (const MCCFIInstruction& Inst : MAI->getInitialFrameState()) {
451       if (Inst.getOperation() == MCCFIInstruction::OpDefCfa ||
452           Inst.getOperation() == MCCFIInstruction::OpDefCfaRegister ||
453           Inst.getOperation() == MCCFIInstruction::OpLLVMDefAspaceCfa) {
454         Frame.CurrentCfaRegister = Inst.getRegister();
455       }
456     }
457   }
458 
459   FrameInfoStack.emplace_back(DwarfFrameInfos.size(), getCurrentSectionOnly());
460   DwarfFrameInfos.push_back(Frame);
461 }
462 
463 void MCStreamer::emitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
464 }
465 
466 void MCStreamer::emitCFIEndProc() {
467   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
468   if (!CurFrame)
469     return;
470   emitCFIEndProcImpl(*CurFrame);
471   FrameInfoStack.pop_back();
472 }
473 
474 void MCStreamer::emitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
475   // Put a dummy non-null value in Frame.End to mark that this frame has been
476   // closed.
477   Frame.End = (MCSymbol *)1;
478 }
479 
480 MCSymbol *MCStreamer::emitCFILabel() {
481   // Return a dummy non-null value so that label fields appear filled in when
482   // generating textual assembly.
483   return (MCSymbol *)1;
484 }
485 
486 void MCStreamer::emitCFIDefCfa(int64_t Register, int64_t Offset, SMLoc Loc) {
487   MCSymbol *Label = emitCFILabel();
488   MCCFIInstruction Instruction =
489       MCCFIInstruction::cfiDefCfa(Label, Register, Offset, Loc);
490   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
491   if (!CurFrame)
492     return;
493   CurFrame->Instructions.push_back(Instruction);
494   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
495 }
496 
497 void MCStreamer::emitCFIDefCfaOffset(int64_t Offset, SMLoc Loc) {
498   MCSymbol *Label = emitCFILabel();
499   MCCFIInstruction Instruction =
500       MCCFIInstruction::cfiDefCfaOffset(Label, Offset);
501   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
502   if (!CurFrame)
503     return;
504   CurFrame->Instructions.push_back(Instruction);
505 }
506 
507 void MCStreamer::emitCFIAdjustCfaOffset(int64_t Adjustment, SMLoc Loc) {
508   MCSymbol *Label = emitCFILabel();
509   MCCFIInstruction Instruction =
510       MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment, Loc);
511   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
512   if (!CurFrame)
513     return;
514   CurFrame->Instructions.push_back(Instruction);
515 }
516 
517 void MCStreamer::emitCFIDefCfaRegister(int64_t Register, SMLoc Loc) {
518   MCSymbol *Label = emitCFILabel();
519   MCCFIInstruction Instruction =
520       MCCFIInstruction::createDefCfaRegister(Label, Register, Loc);
521   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
522   if (!CurFrame)
523     return;
524   CurFrame->Instructions.push_back(Instruction);
525   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
526 }
527 
528 void MCStreamer::emitCFILLVMDefAspaceCfa(int64_t Register, int64_t Offset,
529                                          int64_t AddressSpace, SMLoc Loc) {
530   MCSymbol *Label = emitCFILabel();
531   MCCFIInstruction Instruction = MCCFIInstruction::createLLVMDefAspaceCfa(
532       Label, Register, Offset, AddressSpace, Loc);
533   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
534   if (!CurFrame)
535     return;
536   CurFrame->Instructions.push_back(Instruction);
537   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
538 }
539 
540 void MCStreamer::emitCFIOffset(int64_t Register, int64_t Offset, SMLoc Loc) {
541   MCSymbol *Label = emitCFILabel();
542   MCCFIInstruction Instruction =
543       MCCFIInstruction::createOffset(Label, Register, Offset, Loc);
544   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
545   if (!CurFrame)
546     return;
547   CurFrame->Instructions.push_back(Instruction);
548 }
549 
550 void MCStreamer::emitCFIRelOffset(int64_t Register, int64_t Offset, SMLoc Loc) {
551   MCSymbol *Label = emitCFILabel();
552   MCCFIInstruction Instruction =
553       MCCFIInstruction::createRelOffset(Label, Register, Offset, Loc);
554   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
555   if (!CurFrame)
556     return;
557   CurFrame->Instructions.push_back(Instruction);
558 }
559 
560 void MCStreamer::emitCFIPersonality(const MCSymbol *Sym,
561                                     unsigned Encoding) {
562   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
563   if (!CurFrame)
564     return;
565   CurFrame->Personality = Sym;
566   CurFrame->PersonalityEncoding = Encoding;
567 }
568 
569 void MCStreamer::emitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
570   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
571   if (!CurFrame)
572     return;
573   CurFrame->Lsda = Sym;
574   CurFrame->LsdaEncoding = Encoding;
575 }
576 
577 void MCStreamer::emitCFIRememberState(SMLoc Loc) {
578   MCSymbol *Label = emitCFILabel();
579   MCCFIInstruction Instruction =
580       MCCFIInstruction::createRememberState(Label, Loc);
581   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
582   if (!CurFrame)
583     return;
584   CurFrame->Instructions.push_back(Instruction);
585 }
586 
587 void MCStreamer::emitCFIRestoreState(SMLoc Loc) {
588   // FIXME: Error if there is no matching cfi_remember_state.
589   MCSymbol *Label = emitCFILabel();
590   MCCFIInstruction Instruction =
591       MCCFIInstruction::createRestoreState(Label, Loc);
592   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
593   if (!CurFrame)
594     return;
595   CurFrame->Instructions.push_back(Instruction);
596 }
597 
598 void MCStreamer::emitCFISameValue(int64_t Register, SMLoc Loc) {
599   MCSymbol *Label = emitCFILabel();
600   MCCFIInstruction Instruction =
601       MCCFIInstruction::createSameValue(Label, Register, Loc);
602   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
603   if (!CurFrame)
604     return;
605   CurFrame->Instructions.push_back(Instruction);
606 }
607 
608 void MCStreamer::emitCFIRestore(int64_t Register, SMLoc Loc) {
609   MCSymbol *Label = emitCFILabel();
610   MCCFIInstruction Instruction =
611       MCCFIInstruction::createRestore(Label, Register, Loc);
612   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
613   if (!CurFrame)
614     return;
615   CurFrame->Instructions.push_back(Instruction);
616 }
617 
618 void MCStreamer::emitCFIEscape(StringRef Values, SMLoc Loc) {
619   MCSymbol *Label = emitCFILabel();
620   MCCFIInstruction Instruction =
621       MCCFIInstruction::createEscape(Label, Values, Loc, "");
622   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
623   if (!CurFrame)
624     return;
625   CurFrame->Instructions.push_back(Instruction);
626 }
627 
628 void MCStreamer::emitCFIGnuArgsSize(int64_t Size, SMLoc Loc) {
629   MCSymbol *Label = emitCFILabel();
630   MCCFIInstruction Instruction =
631       MCCFIInstruction::createGnuArgsSize(Label, Size, Loc);
632   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
633   if (!CurFrame)
634     return;
635   CurFrame->Instructions.push_back(Instruction);
636 }
637 
638 void MCStreamer::emitCFISignalFrame() {
639   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
640   if (!CurFrame)
641     return;
642   CurFrame->IsSignalFrame = true;
643 }
644 
645 void MCStreamer::emitCFIUndefined(int64_t Register, SMLoc Loc) {
646   MCSymbol *Label = emitCFILabel();
647   MCCFIInstruction Instruction =
648       MCCFIInstruction::createUndefined(Label, Register, Loc);
649   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
650   if (!CurFrame)
651     return;
652   CurFrame->Instructions.push_back(Instruction);
653 }
654 
655 void MCStreamer::emitCFIRegister(int64_t Register1, int64_t Register2,
656                                  SMLoc Loc) {
657   MCSymbol *Label = emitCFILabel();
658   MCCFIInstruction Instruction =
659       MCCFIInstruction::createRegister(Label, Register1, Register2, Loc);
660   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
661   if (!CurFrame)
662     return;
663   CurFrame->Instructions.push_back(Instruction);
664 }
665 
666 void MCStreamer::emitCFIWindowSave(SMLoc Loc) {
667   MCSymbol *Label = emitCFILabel();
668   MCCFIInstruction Instruction = MCCFIInstruction::createWindowSave(Label, Loc);
669   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
670   if (!CurFrame)
671     return;
672   CurFrame->Instructions.push_back(Instruction);
673 }
674 
675 void MCStreamer::emitCFINegateRAState(SMLoc Loc) {
676   MCSymbol *Label = emitCFILabel();
677   MCCFIInstruction Instruction =
678       MCCFIInstruction::createNegateRAState(Label, Loc);
679   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
680   if (!CurFrame)
681     return;
682   CurFrame->Instructions.push_back(Instruction);
683 }
684 
685 void MCStreamer::emitCFIReturnColumn(int64_t Register) {
686   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
687   if (!CurFrame)
688     return;
689   CurFrame->RAReg = Register;
690 }
691 
692 void MCStreamer::emitCFILabelDirective(SMLoc Loc, StringRef Name) {
693   MCSymbol *Label = emitCFILabel();
694   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
695   if (MCDwarfFrameInfo *F = getCurrentDwarfFrameInfo())
696     F->Instructions.push_back(MCCFIInstruction::createLabel(Label, Sym, Loc));
697 }
698 
699 WinEH::FrameInfo *MCStreamer::EnsureValidWinFrameInfo(SMLoc Loc) {
700   const MCAsmInfo *MAI = Context.getAsmInfo();
701   if (!MAI->usesWindowsCFI()) {
702     getContext().reportError(
703         Loc, ".seh_* directives are not supported on this target");
704     return nullptr;
705   }
706   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End) {
707     getContext().reportError(
708         Loc, ".seh_ directive must appear within an active frame");
709     return nullptr;
710   }
711   return CurrentWinFrameInfo;
712 }
713 
714 void MCStreamer::emitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc) {
715   const MCAsmInfo *MAI = Context.getAsmInfo();
716   if (!MAI->usesWindowsCFI())
717     return getContext().reportError(
718         Loc, ".seh_* directives are not supported on this target");
719   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
720     getContext().reportError(
721         Loc, "Starting a function before ending the previous one!");
722 
723   MCSymbol *StartProc = emitCFILabel();
724 
725   CurrentProcWinFrameInfoStartIndex = WinFrameInfos.size();
726   WinFrameInfos.emplace_back(
727       std::make_unique<WinEH::FrameInfo>(Symbol, StartProc));
728   CurrentWinFrameInfo = WinFrameInfos.back().get();
729   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
730 }
731 
732 void MCStreamer::emitWinCFIEndProc(SMLoc Loc) {
733   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
734   if (!CurFrame)
735     return;
736   if (CurFrame->ChainedParent)
737     getContext().reportError(Loc, "Not all chained regions terminated!");
738 
739   MCSymbol *Label = emitCFILabel();
740   CurFrame->End = Label;
741   if (!CurFrame->FuncletOrFuncEnd)
742     CurFrame->FuncletOrFuncEnd = CurFrame->End;
743 
744   for (size_t I = CurrentProcWinFrameInfoStartIndex, E = WinFrameInfos.size();
745        I != E; ++I)
746     emitWindowsUnwindTables(WinFrameInfos[I].get());
747   switchSection(CurFrame->TextSection);
748 }
749 
750 void MCStreamer::emitWinCFIFuncletOrFuncEnd(SMLoc Loc) {
751   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
752   if (!CurFrame)
753     return;
754   if (CurFrame->ChainedParent)
755     getContext().reportError(Loc, "Not all chained regions terminated!");
756 
757   MCSymbol *Label = emitCFILabel();
758   CurFrame->FuncletOrFuncEnd = Label;
759 }
760 
761 void MCStreamer::emitWinCFIStartChained(SMLoc Loc) {
762   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
763   if (!CurFrame)
764     return;
765 
766   MCSymbol *StartProc = emitCFILabel();
767 
768   WinFrameInfos.emplace_back(std::make_unique<WinEH::FrameInfo>(
769       CurFrame->Function, StartProc, CurFrame));
770   CurrentWinFrameInfo = WinFrameInfos.back().get();
771   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
772 }
773 
774 void MCStreamer::emitWinCFIEndChained(SMLoc Loc) {
775   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
776   if (!CurFrame)
777     return;
778   if (!CurFrame->ChainedParent)
779     return getContext().reportError(
780         Loc, "End of a chained region outside a chained region!");
781 
782   MCSymbol *Label = emitCFILabel();
783 
784   CurFrame->End = Label;
785   CurrentWinFrameInfo = const_cast<WinEH::FrameInfo *>(CurFrame->ChainedParent);
786 }
787 
788 void MCStreamer::emitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
789                                   SMLoc Loc) {
790   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
791   if (!CurFrame)
792     return;
793   if (CurFrame->ChainedParent)
794     return getContext().reportError(
795         Loc, "Chained unwind areas can't have handlers!");
796   CurFrame->ExceptionHandler = Sym;
797   if (!Except && !Unwind)
798     getContext().reportError(Loc, "Don't know what kind of handler this is!");
799   if (Unwind)
800     CurFrame->HandlesUnwind = true;
801   if (Except)
802     CurFrame->HandlesExceptions = true;
803 }
804 
805 void MCStreamer::emitWinEHHandlerData(SMLoc Loc) {
806   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
807   if (!CurFrame)
808     return;
809   if (CurFrame->ChainedParent)
810     getContext().reportError(Loc, "Chained unwind areas can't have handlers!");
811 }
812 
813 void MCStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
814                                     const MCSymbolRefExpr *To, uint64_t Count) {
815 }
816 
817 static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
818                                    MCSection *MainCFISec,
819                                    const MCSection *TextSec) {
820   // If this is the main .text section, use the main unwind info section.
821   if (TextSec == Context.getObjectFileInfo()->getTextSection())
822     return MainCFISec;
823 
824   const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
825   auto *MainCFISecCOFF = cast<MCSectionCOFF>(MainCFISec);
826   unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
827 
828   // If this section is COMDAT, this unwind section should be COMDAT associative
829   // with its group.
830   const MCSymbol *KeySym = nullptr;
831   if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
832     KeySym = TextSecCOFF->getCOMDATSymbol();
833 
834     // In a GNU environment, we can't use associative comdats. Instead, do what
835     // GCC does, which is to make plain comdat selectany section named like
836     // ".[px]data$_Z3foov".
837     if (!Context.getAsmInfo()->hasCOFFAssociativeComdats()) {
838       std::string SectionName = (MainCFISecCOFF->getName() + "$" +
839                                  TextSecCOFF->getName().split('$').second)
840                                     .str();
841       return Context.getCOFFSection(SectionName,
842                                     MainCFISecCOFF->getCharacteristics() |
843                                         COFF::IMAGE_SCN_LNK_COMDAT,
844                                     "", COFF::IMAGE_COMDAT_SELECT_ANY);
845     }
846   }
847 
848   return Context.getAssociativeCOFFSection(MainCFISecCOFF, KeySym, UniqueID);
849 }
850 
851 MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
852   return getWinCFISection(getContext(), &NextWinCFIID,
853                           getContext().getObjectFileInfo()->getPDataSection(),
854                           TextSec);
855 }
856 
857 MCSection *MCStreamer::getAssociatedXDataSection(const MCSection *TextSec) {
858   return getWinCFISection(getContext(), &NextWinCFIID,
859                           getContext().getObjectFileInfo()->getXDataSection(),
860                           TextSec);
861 }
862 
863 void MCStreamer::emitSyntaxDirective() {}
864 
865 static unsigned encodeSEHRegNum(MCContext &Ctx, MCRegister Reg) {
866   return Ctx.getRegisterInfo()->getSEHRegNum(Reg);
867 }
868 
869 void MCStreamer::emitWinCFIPushReg(MCRegister Register, SMLoc Loc) {
870   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
871   if (!CurFrame)
872     return;
873 
874   MCSymbol *Label = emitCFILabel();
875 
876   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(
877       Label, encodeSEHRegNum(Context, Register));
878   CurFrame->Instructions.push_back(Inst);
879 }
880 
881 void MCStreamer::emitWinCFISetFrame(MCRegister Register, unsigned Offset,
882                                     SMLoc Loc) {
883   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
884   if (!CurFrame)
885     return;
886   if (CurFrame->LastFrameInst >= 0)
887     return getContext().reportError(
888         Loc, "frame register and offset can be set at most once");
889   if (Offset & 0x0F)
890     return getContext().reportError(Loc, "offset is not a multiple of 16");
891   if (Offset > 240)
892     return getContext().reportError(
893         Loc, "frame offset must be less than or equal to 240");
894 
895   MCSymbol *Label = emitCFILabel();
896 
897   WinEH::Instruction Inst = Win64EH::Instruction::SetFPReg(
898       Label, encodeSEHRegNum(getContext(), Register), Offset);
899   CurFrame->LastFrameInst = CurFrame->Instructions.size();
900   CurFrame->Instructions.push_back(Inst);
901 }
902 
903 void MCStreamer::emitWinCFIAllocStack(unsigned Size, SMLoc Loc) {
904   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
905   if (!CurFrame)
906     return;
907   if (Size == 0)
908     return getContext().reportError(Loc,
909                                     "stack allocation size must be non-zero");
910   if (Size & 7)
911     return getContext().reportError(
912         Loc, "stack allocation size is not a multiple of 8");
913 
914   MCSymbol *Label = emitCFILabel();
915 
916   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
917   CurFrame->Instructions.push_back(Inst);
918 }
919 
920 void MCStreamer::emitWinCFISaveReg(MCRegister Register, unsigned Offset,
921                                    SMLoc Loc) {
922   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
923   if (!CurFrame)
924     return;
925 
926   if (Offset & 7)
927     return getContext().reportError(
928         Loc, "register save offset is not 8 byte aligned");
929 
930   MCSymbol *Label = emitCFILabel();
931 
932   WinEH::Instruction Inst = Win64EH::Instruction::SaveNonVol(
933       Label, encodeSEHRegNum(Context, Register), Offset);
934   CurFrame->Instructions.push_back(Inst);
935 }
936 
937 void MCStreamer::emitWinCFISaveXMM(MCRegister Register, unsigned Offset,
938                                    SMLoc Loc) {
939   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
940   if (!CurFrame)
941     return;
942   if (Offset & 0x0F)
943     return getContext().reportError(Loc, "offset is not a multiple of 16");
944 
945   MCSymbol *Label = emitCFILabel();
946 
947   WinEH::Instruction Inst = Win64EH::Instruction::SaveXMM(
948       Label, encodeSEHRegNum(Context, Register), Offset);
949   CurFrame->Instructions.push_back(Inst);
950 }
951 
952 void MCStreamer::emitWinCFIPushFrame(bool Code, SMLoc Loc) {
953   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
954   if (!CurFrame)
955     return;
956   if (!CurFrame->Instructions.empty())
957     return getContext().reportError(
958         Loc, "If present, PushMachFrame must be the first UOP");
959 
960   MCSymbol *Label = emitCFILabel();
961 
962   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
963   CurFrame->Instructions.push_back(Inst);
964 }
965 
966 void MCStreamer::emitWinCFIEndProlog(SMLoc Loc) {
967   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
968   if (!CurFrame)
969     return;
970 
971   MCSymbol *Label = emitCFILabel();
972 
973   CurFrame->PrologEnd = Label;
974 }
975 
976 void MCStreamer::emitCOFFSafeSEH(MCSymbol const *Symbol) {}
977 
978 void MCStreamer::emitCOFFSymbolIndex(MCSymbol const *Symbol) {}
979 
980 void MCStreamer::emitCOFFSectionIndex(MCSymbol const *Symbol) {}
981 
982 void MCStreamer::emitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {}
983 
984 void MCStreamer::emitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) {}
985 
986 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
987 /// the specified string in the output .s file.  This capability is
988 /// indicated by the hasRawTextSupport() predicate.
989 void MCStreamer::emitRawTextImpl(StringRef String) {
990   // This is not llvm_unreachable for the sake of out of tree backend
991   // developers who may not have assembly streamers and should serve as a
992   // reminder to not accidentally call EmitRawText in the absence of such.
993   report_fatal_error("EmitRawText called on an MCStreamer that doesn't support "
994                      "it (target backend is likely missing an AsmStreamer "
995                      "implementation)");
996 }
997 
998 void MCStreamer::emitRawText(const Twine &T) {
999   SmallString<128> Str;
1000   emitRawTextImpl(T.toStringRef(Str));
1001 }
1002 
1003 void MCStreamer::emitWindowsUnwindTables() {}
1004 
1005 void MCStreamer::emitWindowsUnwindTables(WinEH::FrameInfo *Frame) {}
1006 
1007 void MCStreamer::finish(SMLoc EndLoc) {
1008   if ((!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End) ||
1009       (!WinFrameInfos.empty() && !WinFrameInfos.back()->End)) {
1010     getContext().reportError(EndLoc, "Unfinished frame!");
1011     return;
1012   }
1013 
1014   MCTargetStreamer *TS = getTargetStreamer();
1015   if (TS)
1016     TS->finish();
1017 
1018   finishImpl();
1019 }
1020 
1021 void MCStreamer::maybeEmitDwarf64Mark() {
1022   if (Context.getDwarfFormat() != dwarf::DWARF64)
1023     return;
1024   AddComment("DWARF64 Mark");
1025   emitInt32(dwarf::DW_LENGTH_DWARF64);
1026 }
1027 
1028 void MCStreamer::emitDwarfUnitLength(uint64_t Length, const Twine &Comment) {
1029   assert(Context.getDwarfFormat() == dwarf::DWARF64 ||
1030          Length <= dwarf::DW_LENGTH_lo_reserved);
1031   maybeEmitDwarf64Mark();
1032   AddComment(Comment);
1033   emitIntValue(Length, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1034 }
1035 
1036 MCSymbol *MCStreamer::emitDwarfUnitLength(const Twine &Prefix,
1037                                           const Twine &Comment) {
1038   maybeEmitDwarf64Mark();
1039   AddComment(Comment);
1040   MCSymbol *Lo = Context.createTempSymbol(Prefix + "_start");
1041   MCSymbol *Hi = Context.createTempSymbol(Prefix + "_end");
1042 
1043   emitAbsoluteSymbolDiff(
1044       Hi, Lo, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
1045   // emit the begin symbol after we generate the length field.
1046   emitLabel(Lo);
1047   // Return the Hi symbol to the caller.
1048   return Hi;
1049 }
1050 
1051 void MCStreamer::emitDwarfLineStartLabel(MCSymbol *StartSym) {
1052   // Set the value of the symbol, as we are at the start of the line table.
1053   emitLabel(StartSym);
1054 }
1055 
1056 void MCStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
1057   visitUsedExpr(*Value);
1058   Symbol->setVariableValue(Value);
1059 
1060   MCTargetStreamer *TS = getTargetStreamer();
1061   if (TS)
1062     TS->emitAssignment(Symbol, Value);
1063 }
1064 
1065 void MCTargetStreamer::prettyPrintAsm(MCInstPrinter &InstPrinter,
1066                                       uint64_t Address, const MCInst &Inst,
1067                                       const MCSubtargetInfo &STI,
1068                                       raw_ostream &OS) {
1069   InstPrinter.printInst(&Inst, Address, "", STI, OS);
1070 }
1071 
1072 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
1073 }
1074 
1075 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
1076   switch (Expr.getKind()) {
1077   case MCExpr::Target:
1078     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
1079     break;
1080 
1081   case MCExpr::Constant:
1082     break;
1083 
1084   case MCExpr::Binary: {
1085     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
1086     visitUsedExpr(*BE.getLHS());
1087     visitUsedExpr(*BE.getRHS());
1088     break;
1089   }
1090 
1091   case MCExpr::SymbolRef:
1092     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
1093     break;
1094 
1095   case MCExpr::Unary:
1096     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
1097     break;
1098   }
1099 }
1100 
1101 void MCStreamer::emitInstruction(const MCInst &Inst, const MCSubtargetInfo &) {
1102   // Scan for values.
1103   for (unsigned i = Inst.getNumOperands(); i--;)
1104     if (Inst.getOperand(i).isExpr())
1105       visitUsedExpr(*Inst.getOperand(i).getExpr());
1106 }
1107 
1108 void MCStreamer::emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
1109                                  uint64_t Attr, uint64_t Discriminator,
1110                                  const MCPseudoProbeInlineStack &InlineStack,
1111                                  MCSymbol *FnSym) {
1112   auto &Context = getContext();
1113 
1114   // Create a symbol at in the current section for use in the probe.
1115   MCSymbol *ProbeSym = Context.createTempSymbol();
1116 
1117   // Set the value of the symbol to use for the MCPseudoProbe.
1118   emitLabel(ProbeSym);
1119 
1120   // Create a (local) probe entry with the symbol.
1121   MCPseudoProbe Probe(ProbeSym, Guid, Index, Type, Attr, Discriminator);
1122 
1123   // Add the probe entry to this section's entries.
1124   Context.getMCPseudoProbeTable().getProbeSections().addPseudoProbe(
1125       FnSym, Probe, InlineStack);
1126 }
1127 
1128 void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
1129                                         unsigned Size) {
1130   // Get the Hi-Lo expression.
1131   const MCExpr *Diff =
1132       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1133                               MCSymbolRefExpr::create(Lo, Context), Context);
1134 
1135   const MCAsmInfo *MAI = Context.getAsmInfo();
1136   if (!MAI->doesSetDirectiveSuppressReloc()) {
1137     emitValue(Diff, Size);
1138     return;
1139   }
1140 
1141   // Otherwise, emit with .set (aka assignment).
1142   MCSymbol *SetLabel = Context.createTempSymbol("set");
1143   emitAssignment(SetLabel, Diff);
1144   emitSymbolValue(SetLabel, Size);
1145 }
1146 
1147 void MCStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
1148                                                  const MCSymbol *Lo) {
1149   // Get the Hi-Lo expression.
1150   const MCExpr *Diff =
1151       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
1152                               MCSymbolRefExpr::create(Lo, Context), Context);
1153 
1154   emitULEB128Value(Diff);
1155 }
1156 
1157 void MCStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {}
1158 void MCStreamer::emitThumbFunc(MCSymbol *Func) {}
1159 void MCStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
1160 void MCStreamer::beginCOFFSymbolDef(const MCSymbol *Symbol) {
1161   llvm_unreachable("this directive only supported on COFF targets");
1162 }
1163 void MCStreamer::endCOFFSymbolDef() {
1164   llvm_unreachable("this directive only supported on COFF targets");
1165 }
1166 void MCStreamer::emitFileDirective(StringRef Filename) {}
1167 void MCStreamer::emitFileDirective(StringRef Filename,
1168                                    StringRef CompilerVersion,
1169                                    StringRef TimeStamp, StringRef Description) {
1170 }
1171 void MCStreamer::emitCOFFSymbolStorageClass(int StorageClass) {
1172   llvm_unreachable("this directive only supported on COFF targets");
1173 }
1174 void MCStreamer::emitCOFFSymbolType(int Type) {
1175   llvm_unreachable("this directive only supported on COFF targets");
1176 }
1177 void MCStreamer::emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
1178                                             MCSymbol *CsectSym,
1179                                             Align Alignment) {
1180   llvm_unreachable("this directive only supported on XCOFF targets");
1181 }
1182 
1183 void MCStreamer::emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol,
1184                                                       MCSymbolAttr Linkage,
1185                                                       MCSymbolAttr Visibility) {
1186   llvm_unreachable("emitXCOFFSymbolLinkageWithVisibility is only supported on "
1187                    "XCOFF targets");
1188 }
1189 
1190 void MCStreamer::emitXCOFFRenameDirective(const MCSymbol *Name,
1191                                           StringRef Rename) {}
1192 
1193 void MCStreamer::emitXCOFFRefDirective(const MCSymbol *Symbol) {
1194   llvm_unreachable("emitXCOFFRefDirective is only supported on XCOFF targets");
1195 }
1196 
1197 void MCStreamer::emitXCOFFExceptDirective(const MCSymbol *Symbol,
1198                                           const MCSymbol *Trap,
1199                                           unsigned Lang, unsigned Reason,
1200                                           unsigned FunctionSize,
1201                                           bool hasDebug) {
1202   report_fatal_error("emitXCOFFExceptDirective is only supported on "
1203                      "XCOFF targets");
1204 }
1205 
1206 void MCStreamer::emitXCOFFCInfoSym(StringRef Name, StringRef Metadata) {
1207   llvm_unreachable("emitXCOFFCInfoSym is only supported on"
1208                    "XCOFF targets");
1209 }
1210 
1211 void MCStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
1212 void MCStreamer::emitELFSymverDirective(const MCSymbol *OriginalSym,
1213                                         StringRef Name, bool KeepOriginalSym) {}
1214 void MCStreamer::emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
1215                                        Align ByteAlignment) {}
1216 void MCStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
1217                                 uint64_t Size, Align ByteAlignment) {}
1218 void MCStreamer::changeSection(MCSection *Section, uint32_t) {
1219   CurFrag = &Section->getDummyFragment();
1220 }
1221 void MCStreamer::emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
1222 void MCStreamer::emitBytes(StringRef Data) {}
1223 void MCStreamer::emitBinaryData(StringRef Data) { emitBytes(Data); }
1224 void MCStreamer::emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) {
1225   visitUsedExpr(*Value);
1226 }
1227 void MCStreamer::emitULEB128Value(const MCExpr *Value) {}
1228 void MCStreamer::emitSLEB128Value(const MCExpr *Value) {}
1229 void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc Loc) {}
1230 void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
1231                           SMLoc Loc) {}
1232 void MCStreamer::emitValueToAlignment(Align Alignment, int64_t Value,
1233                                       unsigned ValueSize,
1234                                       unsigned MaxBytesToEmit) {}
1235 void MCStreamer::emitCodeAlignment(Align Alignment, const MCSubtargetInfo *STI,
1236                                    unsigned MaxBytesToEmit) {}
1237 void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value,
1238                                    SMLoc Loc) {}
1239 void MCStreamer::emitBundleAlignMode(Align Alignment) {}
1240 void MCStreamer::emitBundleLock(bool AlignToEnd) {}
1241 void MCStreamer::finishImpl() {}
1242 void MCStreamer::emitBundleUnlock() {}
1243 
1244 bool MCStreamer::popSection() {
1245   if (SectionStack.size() <= 1)
1246     return false;
1247   auto I = SectionStack.end();
1248   --I;
1249   MCSectionSubPair OldSec = I->first;
1250   --I;
1251   MCSectionSubPair NewSec = I->first;
1252 
1253   if (NewSec.first && OldSec != NewSec)
1254     changeSection(NewSec.first, NewSec.second);
1255   SectionStack.pop_back();
1256   return true;
1257 }
1258 
1259 void MCStreamer::switchSection(MCSection *Section, uint32_t Subsection) {
1260   assert(Section && "Cannot switch to a null section!");
1261   MCSectionSubPair curSection = SectionStack.back().first;
1262   SectionStack.back().second = curSection;
1263   if (MCSectionSubPair(Section, Subsection) != curSection) {
1264     changeSection(Section, Subsection);
1265     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
1266     assert(!Section->hasEnded() && "Section already ended");
1267     MCSymbol *Sym = Section->getBeginSymbol();
1268     if (Sym && !Sym->isInSection())
1269       emitLabel(Sym);
1270   }
1271 }
1272 
1273 bool MCStreamer::switchSection(MCSection *Section, const MCExpr *SubsecExpr) {
1274   int64_t Subsec = 0;
1275   if (SubsecExpr) {
1276     if (!SubsecExpr->evaluateAsAbsolute(Subsec, getAssemblerPtr())) {
1277       getContext().reportError(SubsecExpr->getLoc(),
1278                                "cannot evaluate subsection number");
1279       return true;
1280     }
1281     if (!isUInt<31>(Subsec)) {
1282       getContext().reportError(SubsecExpr->getLoc(),
1283                                "subsection number " + Twine(Subsec) +
1284                                    " is not within [0,2147483647]");
1285       return true;
1286     }
1287   }
1288   switchSection(Section, Subsec);
1289   return false;
1290 }
1291 
1292 void MCStreamer::switchSectionNoPrint(MCSection *Section) {
1293   SectionStack.back().second = SectionStack.back().first;
1294   SectionStack.back().first = MCSectionSubPair(Section, 0);
1295   CurFrag = &Section->getDummyFragment();
1296 }
1297 
1298 MCSymbol *MCStreamer::endSection(MCSection *Section) {
1299   // TODO: keep track of the last subsection so that this symbol appears in the
1300   // correct place.
1301   MCSymbol *Sym = Section->getEndSymbol(Context);
1302   if (Sym->isInSection())
1303     return Sym;
1304 
1305   switchSection(Section);
1306   emitLabel(Sym);
1307   return Sym;
1308 }
1309 
1310 static VersionTuple
1311 targetVersionOrMinimumSupportedOSVersion(const Triple &Target,
1312                                          VersionTuple TargetVersion) {
1313   VersionTuple Min = Target.getMinimumSupportedOSVersion();
1314   return !Min.empty() && Min > TargetVersion ? Min : TargetVersion;
1315 }
1316 
1317 static MCVersionMinType
1318 getMachoVersionMinLoadCommandType(const Triple &Target) {
1319   assert(Target.isOSDarwin() && "expected a darwin OS");
1320   switch (Target.getOS()) {
1321   case Triple::MacOSX:
1322   case Triple::Darwin:
1323     return MCVM_OSXVersionMin;
1324   case Triple::IOS:
1325     assert(!Target.isMacCatalystEnvironment() &&
1326            "mac Catalyst should use LC_BUILD_VERSION");
1327     return MCVM_IOSVersionMin;
1328   case Triple::TvOS:
1329     return MCVM_TvOSVersionMin;
1330   case Triple::WatchOS:
1331     return MCVM_WatchOSVersionMin;
1332   default:
1333     break;
1334   }
1335   llvm_unreachable("unexpected OS type");
1336 }
1337 
1338 static VersionTuple getMachoBuildVersionSupportedOS(const Triple &Target) {
1339   assert(Target.isOSDarwin() && "expected a darwin OS");
1340   switch (Target.getOS()) {
1341   case Triple::MacOSX:
1342   case Triple::Darwin:
1343     return VersionTuple(10, 14);
1344   case Triple::IOS:
1345     // Mac Catalyst always uses the build version load command.
1346     if (Target.isMacCatalystEnvironment())
1347       return VersionTuple();
1348     [[fallthrough]];
1349   case Triple::TvOS:
1350     return VersionTuple(12);
1351   case Triple::WatchOS:
1352     return VersionTuple(5);
1353   case Triple::DriverKit:
1354     // DriverKit always uses the build version load command.
1355     return VersionTuple();
1356   case Triple::XROS:
1357     // XROS always uses the build version load command.
1358     return VersionTuple();
1359   default:
1360     break;
1361   }
1362   llvm_unreachable("unexpected OS type");
1363 }
1364 
1365 static MachO::PlatformType
1366 getMachoBuildVersionPlatformType(const Triple &Target) {
1367   assert(Target.isOSDarwin() && "expected a darwin OS");
1368   switch (Target.getOS()) {
1369   case Triple::MacOSX:
1370   case Triple::Darwin:
1371     return MachO::PLATFORM_MACOS;
1372   case Triple::IOS:
1373     if (Target.isMacCatalystEnvironment())
1374       return MachO::PLATFORM_MACCATALYST;
1375     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_IOSSIMULATOR
1376                                            : MachO::PLATFORM_IOS;
1377   case Triple::TvOS:
1378     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_TVOSSIMULATOR
1379                                            : MachO::PLATFORM_TVOS;
1380   case Triple::WatchOS:
1381     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_WATCHOSSIMULATOR
1382                                            : MachO::PLATFORM_WATCHOS;
1383   case Triple::DriverKit:
1384     return MachO::PLATFORM_DRIVERKIT;
1385   case Triple::XROS:
1386     return Target.isSimulatorEnvironment() ? MachO::PLATFORM_XROS_SIMULATOR
1387                                            : MachO::PLATFORM_XROS;
1388   default:
1389     break;
1390   }
1391   llvm_unreachable("unexpected OS type");
1392 }
1393 
1394 void MCStreamer::emitVersionForTarget(
1395     const Triple &Target, const VersionTuple &SDKVersion,
1396     const Triple *DarwinTargetVariantTriple,
1397     const VersionTuple &DarwinTargetVariantSDKVersion) {
1398   if (!Target.isOSBinFormatMachO() || !Target.isOSDarwin())
1399     return;
1400   // Do we even know the version?
1401   if (Target.getOSMajorVersion() == 0)
1402     return;
1403 
1404   VersionTuple Version;
1405   switch (Target.getOS()) {
1406   case Triple::MacOSX:
1407   case Triple::Darwin:
1408     Target.getMacOSXVersion(Version);
1409     break;
1410   case Triple::IOS:
1411   case Triple::TvOS:
1412     Version = Target.getiOSVersion();
1413     break;
1414   case Triple::WatchOS:
1415     Version = Target.getWatchOSVersion();
1416     break;
1417   case Triple::DriverKit:
1418     Version = Target.getDriverKitVersion();
1419     break;
1420   case Triple::XROS:
1421     Version = Target.getOSVersion();
1422     break;
1423   default:
1424     llvm_unreachable("unexpected OS type");
1425   }
1426   assert(Version.getMajor() != 0 && "A non-zero major version is expected");
1427   auto LinkedTargetVersion =
1428       targetVersionOrMinimumSupportedOSVersion(Target, Version);
1429   auto BuildVersionOSVersion = getMachoBuildVersionSupportedOS(Target);
1430   bool ShouldEmitBuildVersion = false;
1431   if (BuildVersionOSVersion.empty() ||
1432       LinkedTargetVersion >= BuildVersionOSVersion) {
1433     if (Target.isMacCatalystEnvironment() && DarwinTargetVariantTriple &&
1434         DarwinTargetVariantTriple->isMacOSX()) {
1435       emitVersionForTarget(*DarwinTargetVariantTriple,
1436                            DarwinTargetVariantSDKVersion,
1437                            /*DarwinTargetVariantTriple=*/nullptr,
1438                            /*DarwinTargetVariantSDKVersion=*/VersionTuple());
1439       emitDarwinTargetVariantBuildVersion(
1440           getMachoBuildVersionPlatformType(Target),
1441           LinkedTargetVersion.getMajor(),
1442           LinkedTargetVersion.getMinor().value_or(0),
1443           LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1444       return;
1445     }
1446     emitBuildVersion(getMachoBuildVersionPlatformType(Target),
1447                      LinkedTargetVersion.getMajor(),
1448                      LinkedTargetVersion.getMinor().value_or(0),
1449                      LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1450     ShouldEmitBuildVersion = true;
1451   }
1452 
1453   if (const Triple *TVT = DarwinTargetVariantTriple) {
1454     if (Target.isMacOSX() && TVT->isMacCatalystEnvironment()) {
1455       auto TVLinkedTargetVersion =
1456           targetVersionOrMinimumSupportedOSVersion(*TVT, TVT->getiOSVersion());
1457       emitDarwinTargetVariantBuildVersion(
1458           getMachoBuildVersionPlatformType(*TVT),
1459           TVLinkedTargetVersion.getMajor(),
1460           TVLinkedTargetVersion.getMinor().value_or(0),
1461           TVLinkedTargetVersion.getSubminor().value_or(0),
1462           DarwinTargetVariantSDKVersion);
1463     }
1464   }
1465 
1466   if (ShouldEmitBuildVersion)
1467     return;
1468 
1469   emitVersionMin(getMachoVersionMinLoadCommandType(Target),
1470                  LinkedTargetVersion.getMajor(),
1471                  LinkedTargetVersion.getMinor().value_or(0),
1472                  LinkedTargetVersion.getSubminor().value_or(0), SDKVersion);
1473 }
1474