1 //===- AsmPrinter.cpp - Common AsmPrinter code ----------------------------===//
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 // This file implements the AsmPrinter class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/CodeGen/AsmPrinter.h"
14 #include "CodeViewDebug.h"
15 #include "DwarfDebug.h"
16 #include "DwarfException.h"
17 #include "PseudoProbePrinter.h"
18 #include "WasmException.h"
19 #include "WinCFGuard.h"
20 #include "WinException.h"
21 #include "llvm/ADT/APFloat.h"
22 #include "llvm/ADT/APInt.h"
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/ADT/SmallPtrSet.h"
26 #include "llvm/ADT/SmallString.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/ADT/Statistic.h"
29 #include "llvm/ADT/StringExtras.h"
30 #include "llvm/ADT/StringRef.h"
31 #include "llvm/ADT/TinyPtrVector.h"
32 #include "llvm/ADT/Twine.h"
33 #include "llvm/Analysis/ConstantFolding.h"
34 #include "llvm/Analysis/MemoryLocation.h"
35 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
36 #include "llvm/BinaryFormat/COFF.h"
37 #include "llvm/BinaryFormat/Dwarf.h"
38 #include "llvm/BinaryFormat/ELF.h"
39 #include "llvm/CodeGen/GCMetadata.h"
40 #include "llvm/CodeGen/GCMetadataPrinter.h"
41 #include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
42 #include "llvm/CodeGen/MachineBasicBlock.h"
43 #include "llvm/CodeGen/MachineConstantPool.h"
44 #include "llvm/CodeGen/MachineDominators.h"
45 #include "llvm/CodeGen/MachineFrameInfo.h"
46 #include "llvm/CodeGen/MachineFunction.h"
47 #include "llvm/CodeGen/MachineFunctionPass.h"
48 #include "llvm/CodeGen/MachineInstr.h"
49 #include "llvm/CodeGen/MachineInstrBundle.h"
50 #include "llvm/CodeGen/MachineJumpTableInfo.h"
51 #include "llvm/CodeGen/MachineLoopInfo.h"
52 #include "llvm/CodeGen/MachineModuleInfo.h"
53 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
54 #include "llvm/CodeGen/MachineOperand.h"
55 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
56 #include "llvm/CodeGen/StackMaps.h"
57 #include "llvm/CodeGen/TargetFrameLowering.h"
58 #include "llvm/CodeGen/TargetInstrInfo.h"
59 #include "llvm/CodeGen/TargetLowering.h"
60 #include "llvm/CodeGen/TargetOpcodes.h"
61 #include "llvm/CodeGen/TargetRegisterInfo.h"
62 #include "llvm/Config/config.h"
63 #include "llvm/IR/BasicBlock.h"
64 #include "llvm/IR/Comdat.h"
65 #include "llvm/IR/Constant.h"
66 #include "llvm/IR/Constants.h"
67 #include "llvm/IR/DataLayout.h"
68 #include "llvm/IR/DebugInfoMetadata.h"
69 #include "llvm/IR/DerivedTypes.h"
70 #include "llvm/IR/EHPersonalities.h"
71 #include "llvm/IR/Function.h"
72 #include "llvm/IR/GCStrategy.h"
73 #include "llvm/IR/GlobalAlias.h"
74 #include "llvm/IR/GlobalIFunc.h"
75 #include "llvm/IR/GlobalObject.h"
76 #include "llvm/IR/GlobalValue.h"
77 #include "llvm/IR/GlobalVariable.h"
78 #include "llvm/IR/Instruction.h"
79 #include "llvm/IR/Mangler.h"
80 #include "llvm/IR/Metadata.h"
81 #include "llvm/IR/Module.h"
82 #include "llvm/IR/Operator.h"
83 #include "llvm/IR/PseudoProbe.h"
84 #include "llvm/IR/Type.h"
85 #include "llvm/IR/Value.h"
86 #include "llvm/IR/ValueHandle.h"
87 #include "llvm/MC/MCAsmInfo.h"
88 #include "llvm/MC/MCContext.h"
89 #include "llvm/MC/MCDirectives.h"
90 #include "llvm/MC/MCExpr.h"
91 #include "llvm/MC/MCInst.h"
92 #include "llvm/MC/MCSection.h"
93 #include "llvm/MC/MCSectionCOFF.h"
94 #include "llvm/MC/MCSectionELF.h"
95 #include "llvm/MC/MCSectionMachO.h"
96 #include "llvm/MC/MCStreamer.h"
97 #include "llvm/MC/MCSubtargetInfo.h"
98 #include "llvm/MC/MCSymbol.h"
99 #include "llvm/MC/MCSymbolELF.h"
100 #include "llvm/MC/MCTargetOptions.h"
101 #include "llvm/MC/MCValue.h"
102 #include "llvm/MC/SectionKind.h"
103 #include "llvm/Object/ELFTypes.h"
104 #include "llvm/Pass.h"
105 #include "llvm/Remarks/RemarkStreamer.h"
106 #include "llvm/Support/Casting.h"
107 #include "llvm/Support/Compiler.h"
108 #include "llvm/Support/ErrorHandling.h"
109 #include "llvm/Support/FileSystem.h"
110 #include "llvm/Support/Format.h"
111 #include "llvm/Support/MathExtras.h"
112 #include "llvm/Support/Path.h"
113 #include "llvm/Support/Timer.h"
114 #include "llvm/Support/raw_ostream.h"
115 #include "llvm/Target/TargetLoweringObjectFile.h"
116 #include "llvm/Target/TargetMachine.h"
117 #include "llvm/Target/TargetOptions.h"
118 #include "llvm/TargetParser/Triple.h"
119 #include <algorithm>
120 #include <cassert>
121 #include <cinttypes>
122 #include <cstdint>
123 #include <iterator>
124 #include <memory>
125 #include <optional>
126 #include <string>
127 #include <utility>
128 #include <vector>
129 
130 using namespace llvm;
131 
132 #define DEBUG_TYPE "asm-printer"
133 
134 static cl::opt<std::string> BasicBlockProfileDump(
135     "mbb-profile-dump", cl::Hidden,
136     cl::desc("Basic block profile dump for external cost modelling. If "
137              "matching up BBs with afterwards, the compilation must be "
138              "performed with -basic-block-sections=labels. Enabling this "
139              "flag during in-process ThinLTO is not supported."));
140 
141 const char DWARFGroupName[] = "dwarf";
142 const char DWARFGroupDescription[] = "DWARF Emission";
143 const char DbgTimerName[] = "emit";
144 const char DbgTimerDescription[] = "Debug Info Emission";
145 const char EHTimerName[] = "write_exception";
146 const char EHTimerDescription[] = "DWARF Exception Writer";
147 const char CFGuardName[] = "Control Flow Guard";
148 const char CFGuardDescription[] = "Control Flow Guard";
149 const char CodeViewLineTablesGroupName[] = "linetables";
150 const char CodeViewLineTablesGroupDescription[] = "CodeView Line Tables";
151 const char PPTimerName[] = "emit";
152 const char PPTimerDescription[] = "Pseudo Probe Emission";
153 const char PPGroupName[] = "pseudo probe";
154 const char PPGroupDescription[] = "Pseudo Probe Emission";
155 
156 STATISTIC(EmittedInsts, "Number of machine instrs printed");
157 
158 char AsmPrinter::ID = 0;
159 
160 namespace {
161 class AddrLabelMapCallbackPtr final : CallbackVH {
162   AddrLabelMap *Map = nullptr;
163 
164 public:
165   AddrLabelMapCallbackPtr() = default;
166   AddrLabelMapCallbackPtr(Value *V) : CallbackVH(V) {}
167 
168   void setPtr(BasicBlock *BB) {
169     ValueHandleBase::operator=(BB);
170   }
171 
172   void setMap(AddrLabelMap *map) { Map = map; }
173 
174   void deleted() override;
175   void allUsesReplacedWith(Value *V2) override;
176 };
177 } // namespace
178 
179 class llvm::AddrLabelMap {
180   MCContext &Context;
181   struct AddrLabelSymEntry {
182     /// The symbols for the label.
183     TinyPtrVector<MCSymbol *> Symbols;
184 
185     Function *Fn;   // The containing function of the BasicBlock.
186     unsigned Index; // The index in BBCallbacks for the BasicBlock.
187   };
188 
189   DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
190 
191   /// Callbacks for the BasicBlock's that we have entries for.  We use this so
192   /// we get notified if a block is deleted or RAUWd.
193   std::vector<AddrLabelMapCallbackPtr> BBCallbacks;
194 
195   /// This is a per-function list of symbols whose corresponding BasicBlock got
196   /// deleted.  These symbols need to be emitted at some point in the file, so
197   /// AsmPrinter emits them after the function body.
198   DenseMap<AssertingVH<Function>, std::vector<MCSymbol *>>
199       DeletedAddrLabelsNeedingEmission;
200 
201 public:
202   AddrLabelMap(MCContext &context) : Context(context) {}
203 
204   ~AddrLabelMap() {
205     assert(DeletedAddrLabelsNeedingEmission.empty() &&
206            "Some labels for deleted blocks never got emitted");
207   }
208 
209   ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);
210 
211   void takeDeletedSymbolsForFunction(Function *F,
212                                      std::vector<MCSymbol *> &Result);
213 
214   void UpdateForDeletedBlock(BasicBlock *BB);
215   void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
216 };
217 
218 ArrayRef<MCSymbol *> AddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
219   assert(BB->hasAddressTaken() &&
220          "Shouldn't get label for block without address taken");
221   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
222 
223   // If we already had an entry for this block, just return it.
224   if (!Entry.Symbols.empty()) {
225     assert(BB->getParent() == Entry.Fn && "Parent changed");
226     return Entry.Symbols;
227   }
228 
229   // Otherwise, this is a new entry, create a new symbol for it and add an
230   // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
231   BBCallbacks.emplace_back(BB);
232   BBCallbacks.back().setMap(this);
233   Entry.Index = BBCallbacks.size() - 1;
234   Entry.Fn = BB->getParent();
235   MCSymbol *Sym = BB->hasAddressTaken() ? Context.createNamedTempSymbol()
236                                         : Context.createTempSymbol();
237   Entry.Symbols.push_back(Sym);
238   return Entry.Symbols;
239 }
240 
241 /// If we have any deleted symbols for F, return them.
242 void AddrLabelMap::takeDeletedSymbolsForFunction(
243     Function *F, std::vector<MCSymbol *> &Result) {
244   DenseMap<AssertingVH<Function>, std::vector<MCSymbol *>>::iterator I =
245       DeletedAddrLabelsNeedingEmission.find(F);
246 
247   // If there are no entries for the function, just return.
248   if (I == DeletedAddrLabelsNeedingEmission.end())
249     return;
250 
251   // Otherwise, take the list.
252   std::swap(Result, I->second);
253   DeletedAddrLabelsNeedingEmission.erase(I);
254 }
255 
256 //===- Address of Block Management ----------------------------------------===//
257 
258 ArrayRef<MCSymbol *>
259 AsmPrinter::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
260   // Lazily create AddrLabelSymbols.
261   if (!AddrLabelSymbols)
262     AddrLabelSymbols = std::make_unique<AddrLabelMap>(OutContext);
263   return AddrLabelSymbols->getAddrLabelSymbolToEmit(
264       const_cast<BasicBlock *>(BB));
265 }
266 
267 void AsmPrinter::takeDeletedSymbolsForFunction(
268     const Function *F, std::vector<MCSymbol *> &Result) {
269   // If no blocks have had their addresses taken, we're done.
270   if (!AddrLabelSymbols)
271     return;
272   return AddrLabelSymbols->takeDeletedSymbolsForFunction(
273       const_cast<Function *>(F), Result);
274 }
275 
276 void AddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
277   // If the block got deleted, there is no need for the symbol.  If the symbol
278   // was already emitted, we can just forget about it, otherwise we need to
279   // queue it up for later emission when the function is output.
280   AddrLabelSymEntry Entry = std::move(AddrLabelSymbols[BB]);
281   AddrLabelSymbols.erase(BB);
282   assert(!Entry.Symbols.empty() && "Didn't have a symbol, why a callback?");
283   BBCallbacks[Entry.Index] = nullptr; // Clear the callback.
284 
285 #if !LLVM_MEMORY_SANITIZER_BUILD
286   // BasicBlock is destroyed already, so this access is UB detectable by msan.
287   assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
288          "Block/parent mismatch");
289 #endif
290 
291   for (MCSymbol *Sym : Entry.Symbols) {
292     if (Sym->isDefined())
293       return;
294 
295     // If the block is not yet defined, we need to emit it at the end of the
296     // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
297     // for the containing Function.  Since the block is being deleted, its
298     // parent may already be removed, we have to get the function from 'Entry'.
299     DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
300   }
301 }
302 
303 void AddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
304   // Get the entry for the RAUW'd block and remove it from our map.
305   AddrLabelSymEntry OldEntry = std::move(AddrLabelSymbols[Old]);
306   AddrLabelSymbols.erase(Old);
307   assert(!OldEntry.Symbols.empty() && "Didn't have a symbol, why a callback?");
308 
309   AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
310 
311   // If New is not address taken, just move our symbol over to it.
312   if (NewEntry.Symbols.empty()) {
313     BBCallbacks[OldEntry.Index].setPtr(New); // Update the callback.
314     NewEntry = std::move(OldEntry);          // Set New's entry.
315     return;
316   }
317 
318   BBCallbacks[OldEntry.Index] = nullptr; // Update the callback.
319 
320   // Otherwise, we need to add the old symbols to the new block's set.
321   llvm::append_range(NewEntry.Symbols, OldEntry.Symbols);
322 }
323 
324 void AddrLabelMapCallbackPtr::deleted() {
325   Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
326 }
327 
328 void AddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
329   Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
330 }
331 
332 /// getGVAlignment - Return the alignment to use for the specified global
333 /// value.  This rounds up to the preferred alignment if possible and legal.
334 Align AsmPrinter::getGVAlignment(const GlobalObject *GV, const DataLayout &DL,
335                                  Align InAlign) {
336   Align Alignment;
337   if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
338     Alignment = DL.getPreferredAlign(GVar);
339 
340   // If InAlign is specified, round it to it.
341   if (InAlign > Alignment)
342     Alignment = InAlign;
343 
344   // If the GV has a specified alignment, take it into account.
345   const MaybeAlign GVAlign(GV->getAlign());
346   if (!GVAlign)
347     return Alignment;
348 
349   assert(GVAlign && "GVAlign must be set");
350 
351   // If the GVAlign is larger than NumBits, or if we are required to obey
352   // NumBits because the GV has an assigned section, obey it.
353   if (*GVAlign > Alignment || GV->hasSection())
354     Alignment = *GVAlign;
355   return Alignment;
356 }
357 
358 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
359     : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
360       OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)),
361       SM(*this) {
362   VerboseAsm = OutStreamer->isVerboseAsm();
363   DwarfUsesRelocationsAcrossSections =
364       MAI->doesDwarfUseRelocationsAcrossSections();
365 }
366 
367 AsmPrinter::~AsmPrinter() {
368   assert(!DD && Handlers.size() == NumUserHandlers &&
369          "Debug/EH info didn't get finalized");
370 }
371 
372 bool AsmPrinter::isPositionIndependent() const {
373   return TM.isPositionIndependent();
374 }
375 
376 /// getFunctionNumber - Return a unique ID for the current function.
377 unsigned AsmPrinter::getFunctionNumber() const {
378   return MF->getFunctionNumber();
379 }
380 
381 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
382   return *TM.getObjFileLowering();
383 }
384 
385 const DataLayout &AsmPrinter::getDataLayout() const {
386   return MMI->getModule()->getDataLayout();
387 }
388 
389 // Do not use the cached DataLayout because some client use it without a Module
390 // (dsymutil, llvm-dwarfdump).
391 unsigned AsmPrinter::getPointerSize() const {
392   return TM.getPointerSize(0); // FIXME: Default address space
393 }
394 
395 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
396   assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
397   return MF->getSubtarget<MCSubtargetInfo>();
398 }
399 
400 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
401   S.emitInstruction(Inst, getSubtargetInfo());
402 }
403 
404 void AsmPrinter::emitInitialRawDwarfLocDirective(const MachineFunction &MF) {
405   if (DD) {
406     assert(OutStreamer->hasRawTextSupport() &&
407            "Expected assembly output mode.");
408     // This is NVPTX specific and it's unclear why.
409     // PR51079: If we have code without debug information we need to give up.
410     DISubprogram *MFSP = MF.getFunction().getSubprogram();
411     if (!MFSP)
412       return;
413     (void)DD->emitInitialLocDirective(MF, /*CUID=*/0);
414   }
415 }
416 
417 /// getCurrentSection() - Return the current section we are emitting to.
418 const MCSection *AsmPrinter::getCurrentSection() const {
419   return OutStreamer->getCurrentSectionOnly();
420 }
421 
422 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
423   AU.setPreservesAll();
424   MachineFunctionPass::getAnalysisUsage(AU);
425   AU.addRequired<MachineOptimizationRemarkEmitterPass>();
426   AU.addRequired<GCModuleInfo>();
427   AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
428 }
429 
430 bool AsmPrinter::doInitialization(Module &M) {
431   auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>();
432   MMI = MMIWP ? &MMIWP->getMMI() : nullptr;
433   HasSplitStack = false;
434   HasNoSplitStack = false;
435 
436   AddrLabelSymbols = nullptr;
437 
438   // Initialize TargetLoweringObjectFile.
439   const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
440     .Initialize(OutContext, TM);
441 
442   const_cast<TargetLoweringObjectFile &>(getObjFileLowering())
443       .getModuleMetadata(M);
444 
445   OutStreamer->initSections(false, *TM.getMCSubtargetInfo());
446 
447   // Emit the version-min deployment target directive if needed.
448   //
449   // FIXME: If we end up with a collection of these sorts of Darwin-specific
450   // or ELF-specific things, it may make sense to have a platform helper class
451   // that will work with the target helper class. For now keep it here, as the
452   // alternative is duplicated code in each of the target asm printers that
453   // use the directive, where it would need the same conditionalization
454   // anyway.
455   const Triple &Target = TM.getTargetTriple();
456   Triple TVT(M.getDarwinTargetVariantTriple());
457   OutStreamer->emitVersionForTarget(
458       Target, M.getSDKVersion(),
459       M.getDarwinTargetVariantTriple().empty() ? nullptr : &TVT,
460       M.getDarwinTargetVariantSDKVersion());
461 
462   // Allow the target to emit any magic that it wants at the start of the file.
463   emitStartOfAsmFile(M);
464 
465   // Very minimal debug info. It is ignored if we emit actual debug info. If we
466   // don't, this at least helps the user find where a global came from.
467   if (MAI->hasSingleParameterDotFile()) {
468     // .file "foo.c"
469 
470     SmallString<128> FileName;
471     if (MAI->hasBasenameOnlyForFileDirective())
472       FileName = llvm::sys::path::filename(M.getSourceFileName());
473     else
474       FileName = M.getSourceFileName();
475     if (MAI->hasFourStringsDotFile()) {
476 #ifdef PACKAGE_VENDOR
477       const char VerStr[] =
478           PACKAGE_VENDOR " " PACKAGE_NAME " version " PACKAGE_VERSION;
479 #else
480       const char VerStr[] = PACKAGE_NAME " version " PACKAGE_VERSION;
481 #endif
482       // TODO: Add timestamp and description.
483       OutStreamer->emitFileDirective(FileName, VerStr, "", "");
484     } else {
485       OutStreamer->emitFileDirective(FileName);
486     }
487   }
488 
489   // On AIX, emit bytes for llvm.commandline metadata after .file so that the
490   // C_INFO symbol is preserved if any csect is kept by the linker.
491   if (TM.getTargetTriple().isOSBinFormatXCOFF())
492     emitModuleCommandLines(M);
493 
494   GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
495   assert(MI && "AsmPrinter didn't require GCModuleInfo?");
496   for (const auto &I : *MI)
497     if (GCMetadataPrinter *MP = getOrCreateGCPrinter(*I))
498       MP->beginAssembly(M, *MI, *this);
499 
500   // Emit module-level inline asm if it exists.
501   if (!M.getModuleInlineAsm().empty()) {
502     OutStreamer->AddComment("Start of file scope inline assembly");
503     OutStreamer->addBlankLine();
504     emitInlineAsm(M.getModuleInlineAsm() + "\n", *TM.getMCSubtargetInfo(),
505                   TM.Options.MCOptions);
506     OutStreamer->AddComment("End of file scope inline assembly");
507     OutStreamer->addBlankLine();
508   }
509 
510   if (MAI->doesSupportDebugInformation()) {
511     bool EmitCodeView = M.getCodeViewFlag();
512     if (EmitCodeView && TM.getTargetTriple().isOSWindows()) {
513       Handlers.emplace_back(std::make_unique<CodeViewDebug>(this),
514                             DbgTimerName, DbgTimerDescription,
515                             CodeViewLineTablesGroupName,
516                             CodeViewLineTablesGroupDescription);
517     }
518     if (!EmitCodeView || M.getDwarfVersion()) {
519       if (MMI->hasDebugInfo()) {
520         DD = new DwarfDebug(this);
521         Handlers.emplace_back(std::unique_ptr<DwarfDebug>(DD), DbgTimerName,
522                               DbgTimerDescription, DWARFGroupName,
523                               DWARFGroupDescription);
524       }
525     }
526   }
527 
528   if (M.getNamedMetadata(PseudoProbeDescMetadataName)) {
529     PP = new PseudoProbeHandler(this);
530     Handlers.emplace_back(std::unique_ptr<PseudoProbeHandler>(PP), PPTimerName,
531                           PPTimerDescription, PPGroupName, PPGroupDescription);
532   }
533 
534   switch (MAI->getExceptionHandlingType()) {
535   case ExceptionHandling::None:
536     // We may want to emit CFI for debug.
537     [[fallthrough]];
538   case ExceptionHandling::SjLj:
539   case ExceptionHandling::DwarfCFI:
540   case ExceptionHandling::ARM:
541     for (auto &F : M.getFunctionList()) {
542       if (getFunctionCFISectionType(F) != CFISection::None)
543         ModuleCFISection = getFunctionCFISectionType(F);
544       // If any function needsUnwindTableEntry(), it needs .eh_frame and hence
545       // the module needs .eh_frame. If we have found that case, we are done.
546       if (ModuleCFISection == CFISection::EH)
547         break;
548     }
549     assert(MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI ||
550            usesCFIWithoutEH() || ModuleCFISection != CFISection::EH);
551     break;
552   default:
553     break;
554   }
555 
556   EHStreamer *ES = nullptr;
557   switch (MAI->getExceptionHandlingType()) {
558   case ExceptionHandling::None:
559     if (!usesCFIWithoutEH())
560       break;
561     [[fallthrough]];
562   case ExceptionHandling::SjLj:
563   case ExceptionHandling::DwarfCFI:
564     ES = new DwarfCFIException(this);
565     break;
566   case ExceptionHandling::ARM:
567     ES = new ARMException(this);
568     break;
569   case ExceptionHandling::WinEH:
570     switch (MAI->getWinEHEncodingType()) {
571     default: llvm_unreachable("unsupported unwinding information encoding");
572     case WinEH::EncodingType::Invalid:
573       break;
574     case WinEH::EncodingType::X86:
575     case WinEH::EncodingType::Itanium:
576       ES = new WinException(this);
577       break;
578     }
579     break;
580   case ExceptionHandling::Wasm:
581     ES = new WasmException(this);
582     break;
583   case ExceptionHandling::AIX:
584     ES = new AIXException(this);
585     break;
586   }
587   if (ES)
588     Handlers.emplace_back(std::unique_ptr<EHStreamer>(ES), EHTimerName,
589                           EHTimerDescription, DWARFGroupName,
590                           DWARFGroupDescription);
591 
592   // Emit tables for any value of cfguard flag (i.e. cfguard=1 or cfguard=2).
593   if (mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("cfguard")))
594     Handlers.emplace_back(std::make_unique<WinCFGuard>(this), CFGuardName,
595                           CFGuardDescription, DWARFGroupName,
596                           DWARFGroupDescription);
597 
598   for (const HandlerInfo &HI : Handlers) {
599     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
600                        HI.TimerGroupDescription, TimePassesIsEnabled);
601     HI.Handler->beginModule(&M);
602   }
603 
604   if (!BasicBlockProfileDump.empty()) {
605     std::error_code PossibleFileError;
606     MBBProfileDumpFileOutput = std::make_unique<raw_fd_ostream>(
607         BasicBlockProfileDump, PossibleFileError);
608     if (PossibleFileError) {
609       M.getContext().emitError("Failed to open file for MBB Profile Dump: " +
610                                PossibleFileError.message() + "\n");
611     }
612   }
613 
614   return false;
615 }
616 
617 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
618   if (!MAI.hasWeakDefCanBeHiddenDirective())
619     return false;
620 
621   return GV->canBeOmittedFromSymbolTable();
622 }
623 
624 void AsmPrinter::emitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
625   GlobalValue::LinkageTypes Linkage = GV->getLinkage();
626   switch (Linkage) {
627   case GlobalValue::CommonLinkage:
628   case GlobalValue::LinkOnceAnyLinkage:
629   case GlobalValue::LinkOnceODRLinkage:
630   case GlobalValue::WeakAnyLinkage:
631   case GlobalValue::WeakODRLinkage:
632     if (MAI->hasWeakDefDirective()) {
633       // .globl _foo
634       OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global);
635 
636       if (!canBeHidden(GV, *MAI))
637         // .weak_definition _foo
638         OutStreamer->emitSymbolAttribute(GVSym, MCSA_WeakDefinition);
639       else
640         OutStreamer->emitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
641     } else if (MAI->avoidWeakIfComdat() && GV->hasComdat()) {
642       // .globl _foo
643       OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global);
644       //NOTE: linkonce is handled by the section the symbol was assigned to.
645     } else {
646       // .weak _foo
647       OutStreamer->emitSymbolAttribute(GVSym, MCSA_Weak);
648     }
649     return;
650   case GlobalValue::ExternalLinkage:
651     OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global);
652     return;
653   case GlobalValue::PrivateLinkage:
654   case GlobalValue::InternalLinkage:
655     return;
656   case GlobalValue::ExternalWeakLinkage:
657   case GlobalValue::AvailableExternallyLinkage:
658   case GlobalValue::AppendingLinkage:
659     llvm_unreachable("Should never emit this");
660   }
661   llvm_unreachable("Unknown linkage type!");
662 }
663 
664 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
665                                    const GlobalValue *GV) const {
666   TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
667 }
668 
669 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
670   return TM.getSymbol(GV);
671 }
672 
673 MCSymbol *AsmPrinter::getSymbolPreferLocal(const GlobalValue &GV) const {
674   // On ELF, use .Lfoo$local if GV is a non-interposable GlobalObject with an
675   // exact definion (intersection of GlobalValue::hasExactDefinition() and
676   // !isInterposable()). These linkages include: external, appending, internal,
677   // private. It may be profitable to use a local alias for external. The
678   // assembler would otherwise be conservative and assume a global default
679   // visibility symbol can be interposable, even if the code generator already
680   // assumed it.
681   if (TM.getTargetTriple().isOSBinFormatELF() && GV.canBenefitFromLocalAlias()) {
682     const Module &M = *GV.getParent();
683     if (TM.getRelocationModel() != Reloc::Static &&
684         M.getPIELevel() == PIELevel::Default && GV.isDSOLocal())
685       return getSymbolWithGlobalValueBase(&GV, "$local");
686   }
687   return TM.getSymbol(&GV);
688 }
689 
690 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
691 void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
692   bool IsEmuTLSVar = TM.useEmulatedTLS() && GV->isThreadLocal();
693   assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
694          "No emulated TLS variables in the common section");
695 
696   // Never emit TLS variable xyz in emulated TLS model.
697   // The initialization value is in __emutls_t.xyz instead of xyz.
698   if (IsEmuTLSVar)
699     return;
700 
701   if (GV->hasInitializer()) {
702     // Check to see if this is a special global used by LLVM, if so, emit it.
703     if (emitSpecialLLVMGlobal(GV))
704       return;
705 
706     // Skip the emission of global equivalents. The symbol can be emitted later
707     // on by emitGlobalGOTEquivs in case it turns out to be needed.
708     if (GlobalGOTEquivs.count(getSymbol(GV)))
709       return;
710 
711     if (isVerbose()) {
712       // When printing the control variable __emutls_v.*,
713       // we don't need to print the original TLS variable name.
714       GV->printAsOperand(OutStreamer->getCommentOS(),
715                          /*PrintType=*/false, GV->getParent());
716       OutStreamer->getCommentOS() << '\n';
717     }
718   }
719 
720   MCSymbol *GVSym = getSymbol(GV);
721   MCSymbol *EmittedSym = GVSym;
722 
723   // getOrCreateEmuTLSControlSym only creates the symbol with name and default
724   // attributes.
725   // GV's or GVSym's attributes will be used for the EmittedSym.
726   emitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
727 
728   if (GV->isTagged()) {
729     Triple T = TM.getTargetTriple();
730 
731     if (T.getArch() != Triple::aarch64 || !T.isAndroid())
732       OutContext.reportError(SMLoc(),
733                              "tagged symbols (-fsanitize=memtag-globals) are "
734                              "only supported on AArch64 Android");
735     OutStreamer->emitSymbolAttribute(EmittedSym, MAI->getMemtagAttr());
736   }
737 
738   if (!GV->hasInitializer())   // External globals require no extra code.
739     return;
740 
741   GVSym->redefineIfPossible();
742   if (GVSym->isDefined() || GVSym->isVariable())
743     OutContext.reportError(SMLoc(), "symbol '" + Twine(GVSym->getName()) +
744                                         "' is already defined");
745 
746   if (MAI->hasDotTypeDotSizeDirective())
747     OutStreamer->emitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
748 
749   SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
750 
751   const DataLayout &DL = GV->getParent()->getDataLayout();
752   uint64_t Size = DL.getTypeAllocSize(GV->getValueType());
753 
754   // If the alignment is specified, we *must* obey it.  Overaligning a global
755   // with a specified alignment is a prompt way to break globals emitted to
756   // sections and expected to be contiguous (e.g. ObjC metadata).
757   const Align Alignment = getGVAlignment(GV, DL);
758 
759   for (const HandlerInfo &HI : Handlers) {
760     NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
761                        HI.TimerGroupName, HI.TimerGroupDescription,
762                        TimePassesIsEnabled);
763     HI.Handler->setSymbolSize(GVSym, Size);
764   }
765 
766   // Handle common symbols
767   if (GVKind.isCommon()) {
768     if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
769     // .comm _foo, 42, 4
770     OutStreamer->emitCommonSymbol(GVSym, Size, Alignment);
771     return;
772   }
773 
774   // Determine to which section this global should be emitted.
775   MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
776 
777   // If we have a bss global going to a section that supports the
778   // zerofill directive, do so here.
779   if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
780       TheSection->isVirtualSection()) {
781     if (Size == 0)
782       Size = 1; // zerofill of 0 bytes is undefined.
783     emitLinkage(GV, GVSym);
784     // .zerofill __DATA, __bss, _foo, 400, 5
785     OutStreamer->emitZerofill(TheSection, GVSym, Size, Alignment);
786     return;
787   }
788 
789   // If this is a BSS local symbol and we are emitting in the BSS
790   // section use .lcomm/.comm directive.
791   if (GVKind.isBSSLocal() &&
792       getObjFileLowering().getBSSSection() == TheSection) {
793     if (Size == 0)
794       Size = 1; // .comm Foo, 0 is undefined, avoid it.
795 
796     // Use .lcomm only if it supports user-specified alignment.
797     // Otherwise, while it would still be correct to use .lcomm in some
798     // cases (e.g. when Align == 1), the external assembler might enfore
799     // some -unknown- default alignment behavior, which could cause
800     // spurious differences between external and integrated assembler.
801     // Prefer to simply fall back to .local / .comm in this case.
802     if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
803       // .lcomm _foo, 42
804       OutStreamer->emitLocalCommonSymbol(GVSym, Size, Alignment);
805       return;
806     }
807 
808     // .local _foo
809     OutStreamer->emitSymbolAttribute(GVSym, MCSA_Local);
810     // .comm _foo, 42, 4
811     OutStreamer->emitCommonSymbol(GVSym, Size, Alignment);
812     return;
813   }
814 
815   // Handle thread local data for mach-o which requires us to output an
816   // additional structure of data and mangle the original symbol so that we
817   // can reference it later.
818   //
819   // TODO: This should become an "emit thread local global" method on TLOF.
820   // All of this macho specific stuff should be sunk down into TLOFMachO and
821   // stuff like "TLSExtraDataSection" should no longer be part of the parent
822   // TLOF class.  This will also make it more obvious that stuff like
823   // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
824   // specific code.
825   if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
826     // Emit the .tbss symbol
827     MCSymbol *MangSym =
828         OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
829 
830     if (GVKind.isThreadBSS()) {
831       TheSection = getObjFileLowering().getTLSBSSSection();
832       OutStreamer->emitTBSSSymbol(TheSection, MangSym, Size, Alignment);
833     } else if (GVKind.isThreadData()) {
834       OutStreamer->switchSection(TheSection);
835 
836       emitAlignment(Alignment, GV);
837       OutStreamer->emitLabel(MangSym);
838 
839       emitGlobalConstant(GV->getParent()->getDataLayout(),
840                          GV->getInitializer());
841     }
842 
843     OutStreamer->addBlankLine();
844 
845     // Emit the variable struct for the runtime.
846     MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
847 
848     OutStreamer->switchSection(TLVSect);
849     // Emit the linkage here.
850     emitLinkage(GV, GVSym);
851     OutStreamer->emitLabel(GVSym);
852 
853     // Three pointers in size:
854     //   - __tlv_bootstrap - used to make sure support exists
855     //   - spare pointer, used when mapped by the runtime
856     //   - pointer to mangled symbol above with initializer
857     unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
858     OutStreamer->emitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
859                                 PtrSize);
860     OutStreamer->emitIntValue(0, PtrSize);
861     OutStreamer->emitSymbolValue(MangSym, PtrSize);
862 
863     OutStreamer->addBlankLine();
864     return;
865   }
866 
867   MCSymbol *EmittedInitSym = GVSym;
868 
869   OutStreamer->switchSection(TheSection);
870 
871   emitLinkage(GV, EmittedInitSym);
872   emitAlignment(Alignment, GV);
873 
874   OutStreamer->emitLabel(EmittedInitSym);
875   MCSymbol *LocalAlias = getSymbolPreferLocal(*GV);
876   if (LocalAlias != EmittedInitSym)
877     OutStreamer->emitLabel(LocalAlias);
878 
879   emitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
880 
881   if (MAI->hasDotTypeDotSizeDirective())
882     // .size foo, 42
883     OutStreamer->emitELFSize(EmittedInitSym,
884                              MCConstantExpr::create(Size, OutContext));
885 
886   OutStreamer->addBlankLine();
887 }
888 
889 /// Emit the directive and value for debug thread local expression
890 ///
891 /// \p Value - The value to emit.
892 /// \p Size - The size of the integer (in bytes) to emit.
893 void AsmPrinter::emitDebugValue(const MCExpr *Value, unsigned Size) const {
894   OutStreamer->emitValue(Value, Size);
895 }
896 
897 void AsmPrinter::emitFunctionHeaderComment() {}
898 
899 /// EmitFunctionHeader - This method emits the header for the current
900 /// function.
901 void AsmPrinter::emitFunctionHeader() {
902   const Function &F = MF->getFunction();
903 
904   if (isVerbose())
905     OutStreamer->getCommentOS()
906         << "-- Begin function "
907         << GlobalValue::dropLLVMManglingEscape(F.getName()) << '\n';
908 
909   // Print out constants referenced by the function
910   emitConstantPool();
911 
912   // Print the 'header' of function.
913   // If basic block sections are desired, explicitly request a unique section
914   // for this function's entry block.
915   if (MF->front().isBeginSection())
916     MF->setSection(getObjFileLowering().getUniqueSectionForFunction(F, TM));
917   else
918     MF->setSection(getObjFileLowering().SectionForGlobal(&F, TM));
919   OutStreamer->switchSection(MF->getSection());
920 
921   if (!MAI->hasVisibilityOnlyWithLinkage())
922     emitVisibility(CurrentFnSym, F.getVisibility());
923 
924   if (MAI->needsFunctionDescriptors())
925     emitLinkage(&F, CurrentFnDescSym);
926 
927   emitLinkage(&F, CurrentFnSym);
928   if (MAI->hasFunctionAlignment())
929     emitAlignment(MF->getAlignment(), &F);
930 
931   if (MAI->hasDotTypeDotSizeDirective())
932     OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
933 
934   if (F.hasFnAttribute(Attribute::Cold))
935     OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_Cold);
936 
937   // Emit the prefix data.
938   if (F.hasPrefixData()) {
939     if (MAI->hasSubsectionsViaSymbols()) {
940       // Preserving prefix data on platforms which use subsections-via-symbols
941       // is a bit tricky. Here we introduce a symbol for the prefix data
942       // and use the .alt_entry attribute to mark the function's real entry point
943       // as an alternative entry point to the prefix-data symbol.
944       MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
945       OutStreamer->emitLabel(PrefixSym);
946 
947       emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
948 
949       // Emit an .alt_entry directive for the actual function symbol.
950       OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
951     } else {
952       emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
953     }
954   }
955 
956   // Emit KCFI type information before patchable-function-prefix nops.
957   emitKCFITypeId(*MF);
958 
959   // Emit M NOPs for -fpatchable-function-entry=N,M where M>0. We arbitrarily
960   // place prefix data before NOPs.
961   unsigned PatchableFunctionPrefix = 0;
962   unsigned PatchableFunctionEntry = 0;
963   (void)F.getFnAttribute("patchable-function-prefix")
964       .getValueAsString()
965       .getAsInteger(10, PatchableFunctionPrefix);
966   (void)F.getFnAttribute("patchable-function-entry")
967       .getValueAsString()
968       .getAsInteger(10, PatchableFunctionEntry);
969   if (PatchableFunctionPrefix) {
970     CurrentPatchableFunctionEntrySym =
971         OutContext.createLinkerPrivateTempSymbol();
972     OutStreamer->emitLabel(CurrentPatchableFunctionEntrySym);
973     emitNops(PatchableFunctionPrefix);
974   } else if (PatchableFunctionEntry) {
975     // May be reassigned when emitting the body, to reference the label after
976     // the initial BTI (AArch64) or endbr32/endbr64 (x86).
977     CurrentPatchableFunctionEntrySym = CurrentFnBegin;
978   }
979 
980   // Emit the function prologue data for the indirect call sanitizer.
981   if (const MDNode *MD = F.getMetadata(LLVMContext::MD_func_sanitize)) {
982     assert(MD->getNumOperands() == 2);
983 
984     auto *PrologueSig = mdconst::extract<Constant>(MD->getOperand(0));
985     auto *TypeHash = mdconst::extract<Constant>(MD->getOperand(1));
986     emitGlobalConstant(F.getParent()->getDataLayout(), PrologueSig);
987     emitGlobalConstant(F.getParent()->getDataLayout(), TypeHash);
988   }
989 
990   if (isVerbose()) {
991     F.printAsOperand(OutStreamer->getCommentOS(),
992                      /*PrintType=*/false, F.getParent());
993     emitFunctionHeaderComment();
994     OutStreamer->getCommentOS() << '\n';
995   }
996 
997   // Emit the function descriptor. This is a virtual function to allow targets
998   // to emit their specific function descriptor. Right now it is only used by
999   // the AIX target. The PowerPC 64-bit V1 ELF target also uses function
1000   // descriptors and should be converted to use this hook as well.
1001   if (MAI->needsFunctionDescriptors())
1002     emitFunctionDescriptor();
1003 
1004   // Emit the CurrentFnSym. This is a virtual function to allow targets to do
1005   // their wild and crazy things as required.
1006   emitFunctionEntryLabel();
1007 
1008   // If the function had address-taken blocks that got deleted, then we have
1009   // references to the dangling symbols.  Emit them at the start of the function
1010   // so that we don't get references to undefined symbols.
1011   std::vector<MCSymbol*> DeadBlockSyms;
1012   takeDeletedSymbolsForFunction(&F, DeadBlockSyms);
1013   for (MCSymbol *DeadBlockSym : DeadBlockSyms) {
1014     OutStreamer->AddComment("Address taken block that was later removed");
1015     OutStreamer->emitLabel(DeadBlockSym);
1016   }
1017 
1018   if (CurrentFnBegin) {
1019     if (MAI->useAssignmentForEHBegin()) {
1020       MCSymbol *CurPos = OutContext.createTempSymbol();
1021       OutStreamer->emitLabel(CurPos);
1022       OutStreamer->emitAssignment(CurrentFnBegin,
1023                                  MCSymbolRefExpr::create(CurPos, OutContext));
1024     } else {
1025       OutStreamer->emitLabel(CurrentFnBegin);
1026     }
1027   }
1028 
1029   // Emit pre-function debug and/or EH information.
1030   for (const HandlerInfo &HI : Handlers) {
1031     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1032                        HI.TimerGroupDescription, TimePassesIsEnabled);
1033     HI.Handler->beginFunction(MF);
1034   }
1035   for (const HandlerInfo &HI : Handlers) {
1036     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1037                        HI.TimerGroupDescription, TimePassesIsEnabled);
1038     HI.Handler->beginBasicBlockSection(MF->front());
1039   }
1040 
1041   // Emit the prologue data.
1042   if (F.hasPrologueData())
1043     emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrologueData());
1044 }
1045 
1046 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
1047 /// function.  This can be overridden by targets as required to do custom stuff.
1048 void AsmPrinter::emitFunctionEntryLabel() {
1049   CurrentFnSym->redefineIfPossible();
1050 
1051   // The function label could have already been emitted if two symbols end up
1052   // conflicting due to asm renaming.  Detect this and emit an error.
1053   if (CurrentFnSym->isVariable())
1054     report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
1055                        "' is a protected alias");
1056 
1057   OutStreamer->emitLabel(CurrentFnSym);
1058 
1059   if (TM.getTargetTriple().isOSBinFormatELF()) {
1060     MCSymbol *Sym = getSymbolPreferLocal(MF->getFunction());
1061     if (Sym != CurrentFnSym) {
1062       cast<MCSymbolELF>(Sym)->setType(ELF::STT_FUNC);
1063       CurrentFnBeginLocal = Sym;
1064       OutStreamer->emitLabel(Sym);
1065       if (MAI->hasDotTypeDotSizeDirective())
1066         OutStreamer->emitSymbolAttribute(Sym, MCSA_ELF_TypeFunction);
1067     }
1068   }
1069 }
1070 
1071 /// emitComments - Pretty-print comments for instructions.
1072 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
1073   const MachineFunction *MF = MI.getMF();
1074   const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
1075 
1076   // Check for spills and reloads
1077 
1078   // We assume a single instruction only has a spill or reload, not
1079   // both.
1080   std::optional<unsigned> Size;
1081   if ((Size = MI.getRestoreSize(TII))) {
1082     CommentOS << *Size << "-byte Reload\n";
1083   } else if ((Size = MI.getFoldedRestoreSize(TII))) {
1084     if (*Size) {
1085       if (*Size == unsigned(MemoryLocation::UnknownSize))
1086         CommentOS << "Unknown-size Folded Reload\n";
1087       else
1088         CommentOS << *Size << "-byte Folded Reload\n";
1089     }
1090   } else if ((Size = MI.getSpillSize(TII))) {
1091     CommentOS << *Size << "-byte Spill\n";
1092   } else if ((Size = MI.getFoldedSpillSize(TII))) {
1093     if (*Size) {
1094       if (*Size == unsigned(MemoryLocation::UnknownSize))
1095         CommentOS << "Unknown-size Folded Spill\n";
1096       else
1097         CommentOS << *Size << "-byte Folded Spill\n";
1098     }
1099   }
1100 
1101   // Check for spill-induced copies
1102   if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
1103     CommentOS << " Reload Reuse\n";
1104 }
1105 
1106 /// emitImplicitDef - This method emits the specified machine instruction
1107 /// that is an implicit def.
1108 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
1109   Register RegNo = MI->getOperand(0).getReg();
1110 
1111   SmallString<128> Str;
1112   raw_svector_ostream OS(Str);
1113   OS << "implicit-def: "
1114      << printReg(RegNo, MF->getSubtarget().getRegisterInfo());
1115 
1116   OutStreamer->AddComment(OS.str());
1117   OutStreamer->addBlankLine();
1118 }
1119 
1120 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
1121   std::string Str;
1122   raw_string_ostream OS(Str);
1123   OS << "kill:";
1124   for (const MachineOperand &Op : MI->operands()) {
1125     assert(Op.isReg() && "KILL instruction must have only register operands");
1126     OS << ' ' << (Op.isDef() ? "def " : "killed ")
1127        << printReg(Op.getReg(), AP.MF->getSubtarget().getRegisterInfo());
1128   }
1129   AP.OutStreamer->AddComment(OS.str());
1130   AP.OutStreamer->addBlankLine();
1131 }
1132 
1133 /// emitDebugValueComment - This method handles the target-independent form
1134 /// of DBG_VALUE, returning true if it was able to do so.  A false return
1135 /// means the target will need to handle MI in EmitInstruction.
1136 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
1137   // This code handles only the 4-operand target-independent form.
1138   if (MI->isNonListDebugValue() && MI->getNumOperands() != 4)
1139     return false;
1140 
1141   SmallString<128> Str;
1142   raw_svector_ostream OS(Str);
1143   OS << "DEBUG_VALUE: ";
1144 
1145   const DILocalVariable *V = MI->getDebugVariable();
1146   if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
1147     StringRef Name = SP->getName();
1148     if (!Name.empty())
1149       OS << Name << ":";
1150   }
1151   OS << V->getName();
1152   OS << " <- ";
1153 
1154   const DIExpression *Expr = MI->getDebugExpression();
1155   // First convert this to a non-variadic expression if possible, to simplify
1156   // the output.
1157   if (auto NonVariadicExpr = DIExpression::convertToNonVariadicExpression(Expr))
1158     Expr = *NonVariadicExpr;
1159   // Then, output the possibly-simplified expression.
1160   if (Expr->getNumElements()) {
1161     OS << '[';
1162     ListSeparator LS;
1163     for (auto &Op : Expr->expr_ops()) {
1164       OS << LS << dwarf::OperationEncodingString(Op.getOp());
1165       for (unsigned I = 0; I < Op.getNumArgs(); ++I)
1166         OS << ' ' << Op.getArg(I);
1167     }
1168     OS << "] ";
1169   }
1170 
1171   // Register or immediate value. Register 0 means undef.
1172   for (const MachineOperand &Op : MI->debug_operands()) {
1173     if (&Op != MI->debug_operands().begin())
1174       OS << ", ";
1175     switch (Op.getType()) {
1176     case MachineOperand::MO_FPImmediate: {
1177       APFloat APF = APFloat(Op.getFPImm()->getValueAPF());
1178       Type *ImmTy = Op.getFPImm()->getType();
1179       if (ImmTy->isBFloatTy() || ImmTy->isHalfTy() || ImmTy->isFloatTy() ||
1180           ImmTy->isDoubleTy()) {
1181         OS << APF.convertToDouble();
1182       } else {
1183         // There is no good way to print long double.  Convert a copy to
1184         // double.  Ah well, it's only a comment.
1185         bool ignored;
1186         APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
1187                     &ignored);
1188         OS << "(long double) " << APF.convertToDouble();
1189       }
1190       break;
1191     }
1192     case MachineOperand::MO_Immediate: {
1193       OS << Op.getImm();
1194       break;
1195     }
1196     case MachineOperand::MO_CImmediate: {
1197       Op.getCImm()->getValue().print(OS, false /*isSigned*/);
1198       break;
1199     }
1200     case MachineOperand::MO_TargetIndex: {
1201       OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
1202       break;
1203     }
1204     case MachineOperand::MO_Register:
1205     case MachineOperand::MO_FrameIndex: {
1206       Register Reg;
1207       std::optional<StackOffset> Offset;
1208       if (Op.isReg()) {
1209         Reg = Op.getReg();
1210       } else {
1211         const TargetFrameLowering *TFI =
1212             AP.MF->getSubtarget().getFrameLowering();
1213         Offset = TFI->getFrameIndexReference(*AP.MF, Op.getIndex(), Reg);
1214       }
1215       if (!Reg) {
1216         // Suppress offset, it is not meaningful here.
1217         OS << "undef";
1218         break;
1219       }
1220       // The second operand is only an offset if it's an immediate.
1221       if (MI->isIndirectDebugValue())
1222         Offset = StackOffset::getFixed(MI->getDebugOffset().getImm());
1223       if (Offset)
1224         OS << '[';
1225       OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
1226       if (Offset)
1227         OS << '+' << Offset->getFixed() << ']';
1228       break;
1229     }
1230     default:
1231       llvm_unreachable("Unknown operand type");
1232     }
1233   }
1234 
1235   // NOTE: Want this comment at start of line, don't emit with AddComment.
1236   AP.OutStreamer->emitRawComment(OS.str());
1237   return true;
1238 }
1239 
1240 /// This method handles the target-independent form of DBG_LABEL, returning
1241 /// true if it was able to do so.  A false return means the target will need
1242 /// to handle MI in EmitInstruction.
1243 static bool emitDebugLabelComment(const MachineInstr *MI, AsmPrinter &AP) {
1244   if (MI->getNumOperands() != 1)
1245     return false;
1246 
1247   SmallString<128> Str;
1248   raw_svector_ostream OS(Str);
1249   OS << "DEBUG_LABEL: ";
1250 
1251   const DILabel *V = MI->getDebugLabel();
1252   if (auto *SP = dyn_cast<DISubprogram>(
1253           V->getScope()->getNonLexicalBlockFileScope())) {
1254     StringRef Name = SP->getName();
1255     if (!Name.empty())
1256       OS << Name << ":";
1257   }
1258   OS << V->getName();
1259 
1260   // NOTE: Want this comment at start of line, don't emit with AddComment.
1261   AP.OutStreamer->emitRawComment(OS.str());
1262   return true;
1263 }
1264 
1265 AsmPrinter::CFISection
1266 AsmPrinter::getFunctionCFISectionType(const Function &F) const {
1267   // Ignore functions that won't get emitted.
1268   if (F.isDeclarationForLinker())
1269     return CFISection::None;
1270 
1271   if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
1272       F.needsUnwindTableEntry())
1273     return CFISection::EH;
1274 
1275   if (MAI->usesCFIWithoutEH() && F.hasUWTable())
1276     return CFISection::EH;
1277 
1278   assert(MMI != nullptr && "Invalid machine module info");
1279   if (MMI->hasDebugInfo() || TM.Options.ForceDwarfFrameSection)
1280     return CFISection::Debug;
1281 
1282   return CFISection::None;
1283 }
1284 
1285 AsmPrinter::CFISection
1286 AsmPrinter::getFunctionCFISectionType(const MachineFunction &MF) const {
1287   return getFunctionCFISectionType(MF.getFunction());
1288 }
1289 
1290 bool AsmPrinter::needsSEHMoves() {
1291   return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry();
1292 }
1293 
1294 bool AsmPrinter::usesCFIWithoutEH() const {
1295   return MAI->usesCFIWithoutEH() && ModuleCFISection != CFISection::None;
1296 }
1297 
1298 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
1299   ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
1300   if (!usesCFIWithoutEH() &&
1301       ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
1302       ExceptionHandlingType != ExceptionHandling::ARM)
1303     return;
1304 
1305   if (getFunctionCFISectionType(*MF) == CFISection::None)
1306     return;
1307 
1308   // If there is no "real" instruction following this CFI instruction, skip
1309   // emitting it; it would be beyond the end of the function's FDE range.
1310   auto *MBB = MI.getParent();
1311   auto I = std::next(MI.getIterator());
1312   while (I != MBB->end() && I->isTransient())
1313     ++I;
1314   if (I == MBB->instr_end() &&
1315       MBB->getReverseIterator() == MBB->getParent()->rbegin())
1316     return;
1317 
1318   const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions();
1319   unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
1320   const MCCFIInstruction &CFI = Instrs[CFIIndex];
1321   emitCFIInstruction(CFI);
1322 }
1323 
1324 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
1325   // The operands are the MCSymbol and the frame offset of the allocation.
1326   MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
1327   int FrameOffset = MI.getOperand(1).getImm();
1328 
1329   // Emit a symbol assignment.
1330   OutStreamer->emitAssignment(FrameAllocSym,
1331                              MCConstantExpr::create(FrameOffset, OutContext));
1332 }
1333 
1334 /// Returns the BB metadata to be emitted in the SHT_LLVM_BB_ADDR_MAP section
1335 /// for a given basic block. This can be used to capture more precise profile
1336 /// information.
1337 static uint32_t getBBAddrMapMetadata(const MachineBasicBlock &MBB) {
1338   const TargetInstrInfo *TII = MBB.getParent()->getSubtarget().getInstrInfo();
1339   return object::BBAddrMap::BBEntry::Metadata{
1340       MBB.isReturnBlock(), !MBB.empty() && TII->isTailCall(MBB.back()),
1341       MBB.isEHPad(), const_cast<MachineBasicBlock &>(MBB).canFallThrough(),
1342       !MBB.empty() && MBB.rbegin()->isIndirectBranch()}
1343       .encode();
1344 }
1345 
1346 void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
1347   MCSection *BBAddrMapSection =
1348       getObjFileLowering().getBBAddrMapSection(*MF.getSection());
1349   assert(BBAddrMapSection && ".llvm_bb_addr_map section is not initialized.");
1350 
1351   const MCSymbol *FunctionSymbol = getFunctionBegin();
1352 
1353   OutStreamer->pushSection();
1354   OutStreamer->switchSection(BBAddrMapSection);
1355   OutStreamer->AddComment("version");
1356   uint8_t BBAddrMapVersion = OutStreamer->getContext().getBBAddrMapVersion();
1357   OutStreamer->emitInt8(BBAddrMapVersion);
1358   OutStreamer->AddComment("feature");
1359   OutStreamer->emitInt8(0);
1360   OutStreamer->AddComment("function address");
1361   OutStreamer->emitSymbolValue(FunctionSymbol, getPointerSize());
1362   OutStreamer->AddComment("number of basic blocks");
1363   OutStreamer->emitULEB128IntValue(MF.size());
1364   const MCSymbol *PrevMBBEndSymbol = FunctionSymbol;
1365   // Emit BB Information for each basic block in the function.
1366   for (const MachineBasicBlock &MBB : MF) {
1367     const MCSymbol *MBBSymbol =
1368         MBB.isEntryBlock() ? FunctionSymbol : MBB.getSymbol();
1369     // TODO: Remove this check when version 1 is deprecated.
1370     if (BBAddrMapVersion > 1) {
1371       OutStreamer->AddComment("BB id");
1372       // Emit the BB ID for this basic block.
1373       OutStreamer->emitULEB128IntValue(*MBB.getBBID());
1374     }
1375     // Emit the basic block offset relative to the end of the previous block.
1376     // This is zero unless the block is padded due to alignment.
1377     emitLabelDifferenceAsULEB128(MBBSymbol, PrevMBBEndSymbol);
1378     // Emit the basic block size. When BBs have alignments, their size cannot
1379     // always be computed from their offsets.
1380     emitLabelDifferenceAsULEB128(MBB.getEndSymbol(), MBBSymbol);
1381     // Emit the Metadata.
1382     OutStreamer->emitULEB128IntValue(getBBAddrMapMetadata(MBB));
1383     PrevMBBEndSymbol = MBB.getEndSymbol();
1384   }
1385   OutStreamer->popSection();
1386 }
1387 
1388 void AsmPrinter::emitKCFITrapEntry(const MachineFunction &MF,
1389                                    const MCSymbol *Symbol) {
1390   MCSection *Section =
1391       getObjFileLowering().getKCFITrapSection(*MF.getSection());
1392   if (!Section)
1393     return;
1394 
1395   OutStreamer->pushSection();
1396   OutStreamer->switchSection(Section);
1397 
1398   MCSymbol *Loc = OutContext.createLinkerPrivateTempSymbol();
1399   OutStreamer->emitLabel(Loc);
1400   OutStreamer->emitAbsoluteSymbolDiff(Symbol, Loc, 4);
1401 
1402   OutStreamer->popSection();
1403 }
1404 
1405 void AsmPrinter::emitKCFITypeId(const MachineFunction &MF) {
1406   const Function &F = MF.getFunction();
1407   if (const MDNode *MD = F.getMetadata(LLVMContext::MD_kcfi_type))
1408     emitGlobalConstant(F.getParent()->getDataLayout(),
1409                        mdconst::extract<ConstantInt>(MD->getOperand(0)));
1410 }
1411 
1412 void AsmPrinter::emitPseudoProbe(const MachineInstr &MI) {
1413   if (PP) {
1414     auto GUID = MI.getOperand(0).getImm();
1415     auto Index = MI.getOperand(1).getImm();
1416     auto Type = MI.getOperand(2).getImm();
1417     auto Attr = MI.getOperand(3).getImm();
1418     DILocation *DebugLoc = MI.getDebugLoc();
1419     PP->emitPseudoProbe(GUID, Index, Type, Attr, DebugLoc);
1420   }
1421 }
1422 
1423 void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) {
1424   if (!MF.getTarget().Options.EmitStackSizeSection)
1425     return;
1426 
1427   MCSection *StackSizeSection =
1428       getObjFileLowering().getStackSizesSection(*getCurrentSection());
1429   if (!StackSizeSection)
1430     return;
1431 
1432   const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
1433   // Don't emit functions with dynamic stack allocations.
1434   if (FrameInfo.hasVarSizedObjects())
1435     return;
1436 
1437   OutStreamer->pushSection();
1438   OutStreamer->switchSection(StackSizeSection);
1439 
1440   const MCSymbol *FunctionSymbol = getFunctionBegin();
1441   uint64_t StackSize =
1442       FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
1443   OutStreamer->emitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
1444   OutStreamer->emitULEB128IntValue(StackSize);
1445 
1446   OutStreamer->popSection();
1447 }
1448 
1449 void AsmPrinter::emitStackUsage(const MachineFunction &MF) {
1450   const std::string &OutputFilename = MF.getTarget().Options.StackUsageOutput;
1451 
1452   // OutputFilename empty implies -fstack-usage is not passed.
1453   if (OutputFilename.empty())
1454     return;
1455 
1456   const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
1457   uint64_t StackSize =
1458       FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
1459 
1460   if (StackUsageStream == nullptr) {
1461     std::error_code EC;
1462     StackUsageStream =
1463         std::make_unique<raw_fd_ostream>(OutputFilename, EC, sys::fs::OF_Text);
1464     if (EC) {
1465       errs() << "Could not open file: " << EC.message();
1466       return;
1467     }
1468   }
1469 
1470   *StackUsageStream << MF.getFunction().getParent()->getName();
1471   if (const DISubprogram *DSP = MF.getFunction().getSubprogram())
1472     *StackUsageStream << ':' << DSP->getLine();
1473 
1474   *StackUsageStream << ':' << MF.getName() << '\t' << StackSize << '\t';
1475   if (FrameInfo.hasVarSizedObjects())
1476     *StackUsageStream << "dynamic\n";
1477   else
1478     *StackUsageStream << "static\n";
1479 }
1480 
1481 void AsmPrinter::emitPCSectionsLabel(const MachineFunction &MF,
1482                                      const MDNode &MD) {
1483   MCSymbol *S = MF.getContext().createTempSymbol("pcsection");
1484   OutStreamer->emitLabel(S);
1485   PCSectionsSymbols[&MD].emplace_back(S);
1486 }
1487 
1488 void AsmPrinter::emitPCSections(const MachineFunction &MF) {
1489   const Function &F = MF.getFunction();
1490   if (PCSectionsSymbols.empty() && !F.hasMetadata(LLVMContext::MD_pcsections))
1491     return;
1492 
1493   const CodeModel::Model CM = MF.getTarget().getCodeModel();
1494   const unsigned RelativeRelocSize =
1495       (CM == CodeModel::Medium || CM == CodeModel::Large) ? getPointerSize()
1496                                                           : 4;
1497 
1498   // Switch to PCSection, short-circuiting the common case where the current
1499   // section is still valid (assume most MD_pcsections contain just 1 section).
1500   auto SwitchSection = [&, Prev = StringRef()](const StringRef &Sec) mutable {
1501     if (Sec == Prev)
1502       return;
1503     MCSection *S = getObjFileLowering().getPCSection(Sec, MF.getSection());
1504     assert(S && "PC section is not initialized");
1505     OutStreamer->switchSection(S);
1506     Prev = Sec;
1507   };
1508   // Emit symbols into sections and data as specified in the pcsections MDNode.
1509   auto EmitForMD = [&](const MDNode &MD, ArrayRef<const MCSymbol *> Syms,
1510                        bool Deltas) {
1511     // Expect the first operand to be a section name. After that, a tuple of
1512     // constants may appear, which will simply be emitted into the current
1513     // section (the user of MD_pcsections decides the format of encoded data).
1514     assert(isa<MDString>(MD.getOperand(0)) && "first operand not a string");
1515     bool ConstULEB128 = false;
1516     for (const MDOperand &MDO : MD.operands()) {
1517       if (auto *S = dyn_cast<MDString>(MDO)) {
1518         // Found string, start of new section!
1519         // Find options for this section "<section>!<opts>" - supported options:
1520         //   C = Compress constant integers of size 2-8 bytes as ULEB128.
1521         const StringRef SecWithOpt = S->getString();
1522         const size_t OptStart = SecWithOpt.find('!'); // likely npos
1523         const StringRef Sec = SecWithOpt.substr(0, OptStart);
1524         const StringRef Opts = SecWithOpt.substr(OptStart); // likely empty
1525         ConstULEB128 = Opts.find('C') != StringRef::npos;
1526 #ifndef NDEBUG
1527         for (char O : Opts)
1528           assert((O == '!' || O == 'C') && "Invalid !pcsections options");
1529 #endif
1530         SwitchSection(Sec);
1531         const MCSymbol *Prev = Syms.front();
1532         for (const MCSymbol *Sym : Syms) {
1533           if (Sym == Prev || !Deltas) {
1534             // Use the entry itself as the base of the relative offset.
1535             MCSymbol *Base = MF.getContext().createTempSymbol("pcsection_base");
1536             OutStreamer->emitLabel(Base);
1537             // Emit relative relocation `addr - base`, which avoids a dynamic
1538             // relocation in the final binary. User will get the address with
1539             // `base + addr`.
1540             emitLabelDifference(Sym, Base, RelativeRelocSize);
1541           } else {
1542             // Emit delta between symbol and previous symbol.
1543             if (ConstULEB128)
1544               emitLabelDifferenceAsULEB128(Sym, Prev);
1545             else
1546               emitLabelDifference(Sym, Prev, 4);
1547           }
1548           Prev = Sym;
1549         }
1550       } else {
1551         // Emit auxiliary data after PC.
1552         assert(isa<MDNode>(MDO) && "expecting either string or tuple");
1553         const auto *AuxMDs = cast<MDNode>(MDO);
1554         for (const MDOperand &AuxMDO : AuxMDs->operands()) {
1555           assert(isa<ConstantAsMetadata>(AuxMDO) && "expecting a constant");
1556           const Constant *C = cast<ConstantAsMetadata>(AuxMDO)->getValue();
1557           const DataLayout &DL = F.getParent()->getDataLayout();
1558           const uint64_t Size = DL.getTypeStoreSize(C->getType());
1559 
1560           if (auto *CI = dyn_cast<ConstantInt>(C);
1561               CI && ConstULEB128 && Size > 1 && Size <= 8) {
1562             emitULEB128(CI->getZExtValue());
1563           } else {
1564             emitGlobalConstant(DL, C);
1565           }
1566         }
1567       }
1568     }
1569   };
1570 
1571   OutStreamer->pushSection();
1572   // Emit PCs for function start and function size.
1573   if (const MDNode *MD = F.getMetadata(LLVMContext::MD_pcsections))
1574     EmitForMD(*MD, {getFunctionBegin(), getFunctionEnd()}, true);
1575   // Emit PCs for instructions collected.
1576   for (const auto &MS : PCSectionsSymbols)
1577     EmitForMD(*MS.first, MS.second, false);
1578   OutStreamer->popSection();
1579   PCSectionsSymbols.clear();
1580 }
1581 
1582 /// Returns true if function begin and end labels should be emitted.
1583 static bool needFuncLabels(const MachineFunction &MF) {
1584   MachineModuleInfo &MMI = MF.getMMI();
1585   if (!MF.getLandingPads().empty() || MF.hasEHFunclets() ||
1586       MMI.hasDebugInfo() ||
1587       MF.getFunction().hasMetadata(LLVMContext::MD_pcsections))
1588     return true;
1589 
1590   // We might emit an EH table that uses function begin and end labels even if
1591   // we don't have any landingpads.
1592   if (!MF.getFunction().hasPersonalityFn())
1593     return false;
1594   return !isNoOpWithoutInvoke(
1595       classifyEHPersonality(MF.getFunction().getPersonalityFn()));
1596 }
1597 
1598 /// EmitFunctionBody - This method emits the body and trailer for a
1599 /// function.
1600 void AsmPrinter::emitFunctionBody() {
1601   emitFunctionHeader();
1602 
1603   // Emit target-specific gunk before the function body.
1604   emitFunctionBodyStart();
1605 
1606   if (isVerbose()) {
1607     // Get MachineDominatorTree or compute it on the fly if it's unavailable
1608     MDT = getAnalysisIfAvailable<MachineDominatorTree>();
1609     if (!MDT) {
1610       OwnedMDT = std::make_unique<MachineDominatorTree>();
1611       OwnedMDT->getBase().recalculate(*MF);
1612       MDT = OwnedMDT.get();
1613     }
1614 
1615     // Get MachineLoopInfo or compute it on the fly if it's unavailable
1616     MLI = getAnalysisIfAvailable<MachineLoopInfo>();
1617     if (!MLI) {
1618       OwnedMLI = std::make_unique<MachineLoopInfo>();
1619       OwnedMLI->getBase().analyze(MDT->getBase());
1620       MLI = OwnedMLI.get();
1621     }
1622   }
1623 
1624   // Print out code for the function.
1625   bool HasAnyRealCode = false;
1626   int NumInstsInFunction = 0;
1627   bool IsEHa = MMI->getModule()->getModuleFlag("eh-asynch");
1628 
1629   bool CanDoExtraAnalysis = ORE->allowExtraAnalysis(DEBUG_TYPE);
1630   for (auto &MBB : *MF) {
1631     // Print a label for the basic block.
1632     emitBasicBlockStart(MBB);
1633     DenseMap<StringRef, unsigned> MnemonicCounts;
1634     for (auto &MI : MBB) {
1635       // Print the assembly for the instruction.
1636       if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
1637           !MI.isDebugInstr()) {
1638         HasAnyRealCode = true;
1639         ++NumInstsInFunction;
1640       }
1641 
1642       // If there is a pre-instruction symbol, emit a label for it here.
1643       if (MCSymbol *S = MI.getPreInstrSymbol())
1644         OutStreamer->emitLabel(S);
1645 
1646       if (MDNode *MD = MI.getPCSections())
1647         emitPCSectionsLabel(*MF, *MD);
1648 
1649       for (const HandlerInfo &HI : Handlers) {
1650         NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1651                            HI.TimerGroupDescription, TimePassesIsEnabled);
1652         HI.Handler->beginInstruction(&MI);
1653       }
1654 
1655       if (isVerbose())
1656         emitComments(MI, OutStreamer->getCommentOS());
1657 
1658       switch (MI.getOpcode()) {
1659       case TargetOpcode::CFI_INSTRUCTION:
1660         emitCFIInstruction(MI);
1661         break;
1662       case TargetOpcode::LOCAL_ESCAPE:
1663         emitFrameAlloc(MI);
1664         break;
1665       case TargetOpcode::ANNOTATION_LABEL:
1666       case TargetOpcode::GC_LABEL:
1667         OutStreamer->emitLabel(MI.getOperand(0).getMCSymbol());
1668         break;
1669       case TargetOpcode::EH_LABEL:
1670         OutStreamer->emitLabel(MI.getOperand(0).getMCSymbol());
1671         // For AsynchEH, insert a Nop if followed by a trap inst
1672         //   Or the exception won't be caught.
1673         //   (see MCConstantExpr::create(1,..) in WinException.cpp)
1674         //  Ignore SDiv/UDiv because a DIV with Const-0 divisor
1675         //    must have being turned into an UndefValue.
1676         //  Div with variable opnds won't be the first instruction in
1677         //  an EH region as it must be led by at least a Load
1678         {
1679           auto MI2 = std::next(MI.getIterator());
1680           if (IsEHa && MI2 != MBB.end() &&
1681               (MI2->mayLoadOrStore() || MI2->mayRaiseFPException()))
1682             emitNops(1);
1683         }
1684         break;
1685       case TargetOpcode::INLINEASM:
1686       case TargetOpcode::INLINEASM_BR:
1687         emitInlineAsm(&MI);
1688         break;
1689       case TargetOpcode::DBG_VALUE:
1690       case TargetOpcode::DBG_VALUE_LIST:
1691         if (isVerbose()) {
1692           if (!emitDebugValueComment(&MI, *this))
1693             emitInstruction(&MI);
1694         }
1695         break;
1696       case TargetOpcode::DBG_INSTR_REF:
1697         // This instruction reference will have been resolved to a machine
1698         // location, and a nearby DBG_VALUE created. We can safely ignore
1699         // the instruction reference.
1700         break;
1701       case TargetOpcode::DBG_PHI:
1702         // This instruction is only used to label a program point, it's purely
1703         // meta information.
1704         break;
1705       case TargetOpcode::DBG_LABEL:
1706         if (isVerbose()) {
1707           if (!emitDebugLabelComment(&MI, *this))
1708             emitInstruction(&MI);
1709         }
1710         break;
1711       case TargetOpcode::IMPLICIT_DEF:
1712         if (isVerbose()) emitImplicitDef(&MI);
1713         break;
1714       case TargetOpcode::KILL:
1715         if (isVerbose()) emitKill(&MI, *this);
1716         break;
1717       case TargetOpcode::PSEUDO_PROBE:
1718         emitPseudoProbe(MI);
1719         break;
1720       case TargetOpcode::ARITH_FENCE:
1721         if (isVerbose())
1722           OutStreamer->emitRawComment("ARITH_FENCE");
1723         break;
1724       case TargetOpcode::MEMBARRIER:
1725         OutStreamer->emitRawComment("MEMBARRIER");
1726         break;
1727       default:
1728         emitInstruction(&MI);
1729         if (CanDoExtraAnalysis) {
1730           MCInst MCI;
1731           MCI.setOpcode(MI.getOpcode());
1732           auto Name = OutStreamer->getMnemonic(MCI);
1733           auto I = MnemonicCounts.insert({Name, 0u});
1734           I.first->second++;
1735         }
1736         break;
1737       }
1738 
1739       // If there is a post-instruction symbol, emit a label for it here.
1740       if (MCSymbol *S = MI.getPostInstrSymbol())
1741         OutStreamer->emitLabel(S);
1742 
1743       for (const HandlerInfo &HI : Handlers) {
1744         NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1745                            HI.TimerGroupDescription, TimePassesIsEnabled);
1746         HI.Handler->endInstruction();
1747       }
1748     }
1749 
1750     // We must emit temporary symbol for the end of this basic block, if either
1751     // we have BBLabels enabled or if this basic blocks marks the end of a
1752     // section.
1753     if (MF->hasBBLabels() ||
1754         (MAI->hasDotTypeDotSizeDirective() && MBB.isEndSection()))
1755       OutStreamer->emitLabel(MBB.getEndSymbol());
1756 
1757     if (MBB.isEndSection()) {
1758       // The size directive for the section containing the entry block is
1759       // handled separately by the function section.
1760       if (!MBB.sameSection(&MF->front())) {
1761         if (MAI->hasDotTypeDotSizeDirective()) {
1762           // Emit the size directive for the basic block section.
1763           const MCExpr *SizeExp = MCBinaryExpr::createSub(
1764               MCSymbolRefExpr::create(MBB.getEndSymbol(), OutContext),
1765               MCSymbolRefExpr::create(CurrentSectionBeginSym, OutContext),
1766               OutContext);
1767           OutStreamer->emitELFSize(CurrentSectionBeginSym, SizeExp);
1768         }
1769         MBBSectionRanges[MBB.getSectionIDNum()] =
1770             MBBSectionRange{CurrentSectionBeginSym, MBB.getEndSymbol()};
1771       }
1772     }
1773     emitBasicBlockEnd(MBB);
1774 
1775     if (CanDoExtraAnalysis) {
1776       // Skip empty blocks.
1777       if (MBB.empty())
1778         continue;
1779 
1780       MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionMix",
1781                                           MBB.begin()->getDebugLoc(), &MBB);
1782 
1783       // Generate instruction mix remark. First, sort counts in descending order
1784       // by count and name.
1785       SmallVector<std::pair<StringRef, unsigned>, 128> MnemonicVec;
1786       for (auto &KV : MnemonicCounts)
1787         MnemonicVec.emplace_back(KV.first, KV.second);
1788 
1789       sort(MnemonicVec, [](const std::pair<StringRef, unsigned> &A,
1790                            const std::pair<StringRef, unsigned> &B) {
1791         if (A.second > B.second)
1792           return true;
1793         if (A.second == B.second)
1794           return StringRef(A.first) < StringRef(B.first);
1795         return false;
1796       });
1797       R << "BasicBlock: " << ore::NV("BasicBlock", MBB.getName()) << "\n";
1798       for (auto &KV : MnemonicVec) {
1799         auto Name = (Twine("INST_") + getToken(KV.first.trim()).first).str();
1800         R << KV.first << ": " << ore::NV(Name, KV.second) << "\n";
1801       }
1802       ORE->emit(R);
1803     }
1804   }
1805 
1806   EmittedInsts += NumInstsInFunction;
1807   MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
1808                                       MF->getFunction().getSubprogram(),
1809                                       &MF->front());
1810   R << ore::NV("NumInstructions", NumInstsInFunction)
1811     << " instructions in function";
1812   ORE->emit(R);
1813 
1814   // If the function is empty and the object file uses .subsections_via_symbols,
1815   // then we need to emit *something* to the function body to prevent the
1816   // labels from collapsing together.  Just emit a noop.
1817   // Similarly, don't emit empty functions on Windows either. It can lead to
1818   // duplicate entries (two functions with the same RVA) in the Guard CF Table
1819   // after linking, causing the kernel not to load the binary:
1820   // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
1821   // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
1822   const Triple &TT = TM.getTargetTriple();
1823   if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() ||
1824                           (TT.isOSWindows() && TT.isOSBinFormatCOFF()))) {
1825     MCInst Noop = MF->getSubtarget().getInstrInfo()->getNop();
1826 
1827     // Targets can opt-out of emitting the noop here by leaving the opcode
1828     // unspecified.
1829     if (Noop.getOpcode()) {
1830       OutStreamer->AddComment("avoids zero-length function");
1831       emitNops(1);
1832     }
1833   }
1834 
1835   // Switch to the original section in case basic block sections was used.
1836   OutStreamer->switchSection(MF->getSection());
1837 
1838   const Function &F = MF->getFunction();
1839   for (const auto &BB : F) {
1840     if (!BB.hasAddressTaken())
1841       continue;
1842     MCSymbol *Sym = GetBlockAddressSymbol(&BB);
1843     if (Sym->isDefined())
1844       continue;
1845     OutStreamer->AddComment("Address of block that was removed by CodeGen");
1846     OutStreamer->emitLabel(Sym);
1847   }
1848 
1849   // Emit target-specific gunk after the function body.
1850   emitFunctionBodyEnd();
1851 
1852   // Even though wasm supports .type and .size in general, function symbols
1853   // are automatically sized.
1854   bool EmitFunctionSize = MAI->hasDotTypeDotSizeDirective() && !TT.isWasm();
1855 
1856   if (needFuncLabels(*MF) || EmitFunctionSize) {
1857     // Create a symbol for the end of function.
1858     CurrentFnEnd = createTempSymbol("func_end");
1859     OutStreamer->emitLabel(CurrentFnEnd);
1860   }
1861 
1862   // If the target wants a .size directive for the size of the function, emit
1863   // it.
1864   if (EmitFunctionSize) {
1865     // We can get the size as difference between the function label and the
1866     // temp label.
1867     const MCExpr *SizeExp = MCBinaryExpr::createSub(
1868         MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1869         MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1870     OutStreamer->emitELFSize(CurrentFnSym, SizeExp);
1871     if (CurrentFnBeginLocal)
1872       OutStreamer->emitELFSize(CurrentFnBeginLocal, SizeExp);
1873   }
1874 
1875   // Call endBasicBlockSection on the last block now, if it wasn't already
1876   // called.
1877   if (!MF->back().isEndSection()) {
1878     for (const HandlerInfo &HI : Handlers) {
1879       NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1880                          HI.TimerGroupDescription, TimePassesIsEnabled);
1881       HI.Handler->endBasicBlockSection(MF->back());
1882     }
1883   }
1884   for (const HandlerInfo &HI : Handlers) {
1885     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1886                        HI.TimerGroupDescription, TimePassesIsEnabled);
1887     HI.Handler->markFunctionEnd();
1888   }
1889 
1890   MBBSectionRanges[MF->front().getSectionIDNum()] =
1891       MBBSectionRange{CurrentFnBegin, CurrentFnEnd};
1892 
1893   // Print out jump tables referenced by the function.
1894   emitJumpTableInfo();
1895 
1896   // Emit post-function debug and/or EH information.
1897   for (const HandlerInfo &HI : Handlers) {
1898     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1899                        HI.TimerGroupDescription, TimePassesIsEnabled);
1900     HI.Handler->endFunction(MF);
1901   }
1902 
1903   // Emit section containing BB address offsets and their metadata, when
1904   // BB labels are requested for this function. Skip empty functions.
1905   if (MF->hasBBLabels() && HasAnyRealCode)
1906     emitBBAddrMapSection(*MF);
1907 
1908   // Emit sections containing instruction and function PCs.
1909   emitPCSections(*MF);
1910 
1911   // Emit section containing stack size metadata.
1912   emitStackSizeSection(*MF);
1913 
1914   // Emit .su file containing function stack size information.
1915   emitStackUsage(*MF);
1916 
1917   emitPatchableFunctionEntries();
1918 
1919   if (isVerbose())
1920     OutStreamer->getCommentOS() << "-- End function\n";
1921 
1922   OutStreamer->addBlankLine();
1923 
1924   // Output MBB ids, function names, and frequencies if the flag to dump
1925   // MBB profile information has been set
1926   if (MBBProfileDumpFileOutput) {
1927     if (!MF->hasBBLabels())
1928       MF->getContext().reportError(
1929           SMLoc(),
1930           "Unable to find BB labels for MBB profile dump. -mbb-profile-dump "
1931           "must be called with -basic-block-sections=labels");
1932     MachineBlockFrequencyInfo &MBFI =
1933         getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
1934     for (const auto &MBB : *MF) {
1935       *MBBProfileDumpFileOutput.get()
1936           << MF->getName() << "," << MBB.getBBID() << ","
1937           << MBFI.getBlockFreqRelativeToEntryBlock(&MBB) << "\n";
1938     }
1939   }
1940 }
1941 
1942 /// Compute the number of Global Variables that uses a Constant.
1943 static unsigned getNumGlobalVariableUses(const Constant *C) {
1944   if (!C)
1945     return 0;
1946 
1947   if (isa<GlobalVariable>(C))
1948     return 1;
1949 
1950   unsigned NumUses = 0;
1951   for (const auto *CU : C->users())
1952     NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1953 
1954   return NumUses;
1955 }
1956 
1957 /// Only consider global GOT equivalents if at least one user is a
1958 /// cstexpr inside an initializer of another global variables. Also, don't
1959 /// handle cstexpr inside instructions. During global variable emission,
1960 /// candidates are skipped and are emitted later in case at least one cstexpr
1961 /// isn't replaced by a PC relative GOT entry access.
1962 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1963                                      unsigned &NumGOTEquivUsers) {
1964   // Global GOT equivalents are unnamed private globals with a constant
1965   // pointer initializer to another global symbol. They must point to a
1966   // GlobalVariable or Function, i.e., as GlobalValue.
1967   if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
1968       !GV->isConstant() || !GV->isDiscardableIfUnused() ||
1969       !isa<GlobalValue>(GV->getOperand(0)))
1970     return false;
1971 
1972   // To be a got equivalent, at least one of its users need to be a constant
1973   // expression used by another global variable.
1974   for (const auto *U : GV->users())
1975     NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1976 
1977   return NumGOTEquivUsers > 0;
1978 }
1979 
1980 /// Unnamed constant global variables solely contaning a pointer to
1981 /// another globals variable is equivalent to a GOT table entry; it contains the
1982 /// the address of another symbol. Optimize it and replace accesses to these
1983 /// "GOT equivalents" by using the GOT entry for the final global instead.
1984 /// Compute GOT equivalent candidates among all global variables to avoid
1985 /// emitting them if possible later on, after it use is replaced by a GOT entry
1986 /// access.
1987 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1988   if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1989     return;
1990 
1991   for (const auto &G : M.globals()) {
1992     unsigned NumGOTEquivUsers = 0;
1993     if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1994       continue;
1995 
1996     const MCSymbol *GOTEquivSym = getSymbol(&G);
1997     GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1998   }
1999 }
2000 
2001 /// Constant expressions using GOT equivalent globals may not be eligible
2002 /// for PC relative GOT entry conversion, in such cases we need to emit such
2003 /// globals we previously omitted in EmitGlobalVariable.
2004 void AsmPrinter::emitGlobalGOTEquivs() {
2005   if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
2006     return;
2007 
2008   SmallVector<const GlobalVariable *, 8> FailedCandidates;
2009   for (auto &I : GlobalGOTEquivs) {
2010     const GlobalVariable *GV = I.second.first;
2011     unsigned Cnt = I.second.second;
2012     if (Cnt)
2013       FailedCandidates.push_back(GV);
2014   }
2015   GlobalGOTEquivs.clear();
2016 
2017   for (const auto *GV : FailedCandidates)
2018     emitGlobalVariable(GV);
2019 }
2020 
2021 void AsmPrinter::emitGlobalAlias(Module &M, const GlobalAlias &GA) {
2022   MCSymbol *Name = getSymbol(&GA);
2023   bool IsFunction = GA.getValueType()->isFunctionTy();
2024   // Treat bitcasts of functions as functions also. This is important at least
2025   // on WebAssembly where object and function addresses can't alias each other.
2026   if (!IsFunction)
2027     IsFunction = isa<Function>(GA.getAliasee()->stripPointerCasts());
2028 
2029   // AIX's assembly directive `.set` is not usable for aliasing purpose,
2030   // so AIX has to use the extra-label-at-definition strategy. At this
2031   // point, all the extra label is emitted, we just have to emit linkage for
2032   // those labels.
2033   if (TM.getTargetTriple().isOSBinFormatXCOFF()) {
2034     assert(MAI->hasVisibilityOnlyWithLinkage() &&
2035            "Visibility should be handled with emitLinkage() on AIX.");
2036 
2037     // Linkage for alias of global variable has been emitted.
2038     if (isa<GlobalVariable>(GA.getAliaseeObject()))
2039       return;
2040 
2041     emitLinkage(&GA, Name);
2042     // If it's a function, also emit linkage for aliases of function entry
2043     // point.
2044     if (IsFunction)
2045       emitLinkage(&GA,
2046                   getObjFileLowering().getFunctionEntryPointSymbol(&GA, TM));
2047     return;
2048   }
2049 
2050   if (GA.hasExternalLinkage() || !MAI->getWeakRefDirective())
2051     OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
2052   else if (GA.hasWeakLinkage() || GA.hasLinkOnceLinkage())
2053     OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
2054   else
2055     assert(GA.hasLocalLinkage() && "Invalid alias linkage");
2056 
2057   // Set the symbol type to function if the alias has a function type.
2058   // This affects codegen when the aliasee is not a function.
2059   if (IsFunction) {
2060     OutStreamer->emitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
2061     if (TM.getTargetTriple().isOSBinFormatCOFF()) {
2062       OutStreamer->beginCOFFSymbolDef(Name);
2063       OutStreamer->emitCOFFSymbolStorageClass(
2064           GA.hasLocalLinkage() ? COFF::IMAGE_SYM_CLASS_STATIC
2065                                : COFF::IMAGE_SYM_CLASS_EXTERNAL);
2066       OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
2067                                       << COFF::SCT_COMPLEX_TYPE_SHIFT);
2068       OutStreamer->endCOFFSymbolDef();
2069     }
2070   }
2071 
2072   emitVisibility(Name, GA.getVisibility());
2073 
2074   const MCExpr *Expr = lowerConstant(GA.getAliasee());
2075 
2076   if (MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
2077     OutStreamer->emitSymbolAttribute(Name, MCSA_AltEntry);
2078 
2079   // Emit the directives as assignments aka .set:
2080   OutStreamer->emitAssignment(Name, Expr);
2081   MCSymbol *LocalAlias = getSymbolPreferLocal(GA);
2082   if (LocalAlias != Name)
2083     OutStreamer->emitAssignment(LocalAlias, Expr);
2084 
2085   // If the aliasee does not correspond to a symbol in the output, i.e. the
2086   // alias is not of an object or the aliased object is private, then set the
2087   // size of the alias symbol from the type of the alias. We don't do this in
2088   // other situations as the alias and aliasee having differing types but same
2089   // size may be intentional.
2090   const GlobalObject *BaseObject = GA.getAliaseeObject();
2091   if (MAI->hasDotTypeDotSizeDirective() && GA.getValueType()->isSized() &&
2092       (!BaseObject || BaseObject->hasPrivateLinkage())) {
2093     const DataLayout &DL = M.getDataLayout();
2094     uint64_t Size = DL.getTypeAllocSize(GA.getValueType());
2095     OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
2096   }
2097 }
2098 
2099 void AsmPrinter::emitGlobalIFunc(Module &M, const GlobalIFunc &GI) {
2100   assert(!TM.getTargetTriple().isOSBinFormatXCOFF() &&
2101          "IFunc is not supported on AIX.");
2102 
2103   MCSymbol *Name = getSymbol(&GI);
2104 
2105   if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
2106     OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
2107   else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
2108     OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
2109   else
2110     assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
2111 
2112   OutStreamer->emitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
2113   emitVisibility(Name, GI.getVisibility());
2114 
2115   // Emit the directives as assignments aka .set:
2116   const MCExpr *Expr = lowerConstant(GI.getResolver());
2117   OutStreamer->emitAssignment(Name, Expr);
2118   MCSymbol *LocalAlias = getSymbolPreferLocal(GI);
2119   if (LocalAlias != Name)
2120     OutStreamer->emitAssignment(LocalAlias, Expr);
2121 }
2122 
2123 void AsmPrinter::emitRemarksSection(remarks::RemarkStreamer &RS) {
2124   if (!RS.needsSection())
2125     return;
2126 
2127   remarks::RemarkSerializer &RemarkSerializer = RS.getSerializer();
2128 
2129   std::optional<SmallString<128>> Filename;
2130   if (std::optional<StringRef> FilenameRef = RS.getFilename()) {
2131     Filename = *FilenameRef;
2132     sys::fs::make_absolute(*Filename);
2133     assert(!Filename->empty() && "The filename can't be empty.");
2134   }
2135 
2136   std::string Buf;
2137   raw_string_ostream OS(Buf);
2138   std::unique_ptr<remarks::MetaSerializer> MetaSerializer =
2139       Filename ? RemarkSerializer.metaSerializer(OS, Filename->str())
2140                : RemarkSerializer.metaSerializer(OS);
2141   MetaSerializer->emit();
2142 
2143   // Switch to the remarks section.
2144   MCSection *RemarksSection =
2145       OutContext.getObjectFileInfo()->getRemarksSection();
2146   OutStreamer->switchSection(RemarksSection);
2147 
2148   OutStreamer->emitBinaryData(OS.str());
2149 }
2150 
2151 bool AsmPrinter::doFinalization(Module &M) {
2152   // Set the MachineFunction to nullptr so that we can catch attempted
2153   // accesses to MF specific features at the module level and so that
2154   // we can conditionalize accesses based on whether or not it is nullptr.
2155   MF = nullptr;
2156 
2157   // Gather all GOT equivalent globals in the module. We really need two
2158   // passes over the globals: one to compute and another to avoid its emission
2159   // in EmitGlobalVariable, otherwise we would not be able to handle cases
2160   // where the got equivalent shows up before its use.
2161   computeGlobalGOTEquivs(M);
2162 
2163   // Emit global variables.
2164   for (const auto &G : M.globals())
2165     emitGlobalVariable(&G);
2166 
2167   // Emit remaining GOT equivalent globals.
2168   emitGlobalGOTEquivs();
2169 
2170   const TargetLoweringObjectFile &TLOF = getObjFileLowering();
2171 
2172   // Emit linkage(XCOFF) and visibility info for declarations
2173   for (const Function &F : M) {
2174     if (!F.isDeclarationForLinker())
2175       continue;
2176 
2177     MCSymbol *Name = getSymbol(&F);
2178     // Function getSymbol gives us the function descriptor symbol for XCOFF.
2179 
2180     if (!TM.getTargetTriple().isOSBinFormatXCOFF()) {
2181       GlobalValue::VisibilityTypes V = F.getVisibility();
2182       if (V == GlobalValue::DefaultVisibility)
2183         continue;
2184 
2185       emitVisibility(Name, V, false);
2186       continue;
2187     }
2188 
2189     if (F.isIntrinsic())
2190       continue;
2191 
2192     // Handle the XCOFF case.
2193     // Variable `Name` is the function descriptor symbol (see above). Get the
2194     // function entry point symbol.
2195     MCSymbol *FnEntryPointSym = TLOF.getFunctionEntryPointSymbol(&F, TM);
2196     // Emit linkage for the function entry point.
2197     emitLinkage(&F, FnEntryPointSym);
2198 
2199     // Emit linkage for the function descriptor.
2200     emitLinkage(&F, Name);
2201   }
2202 
2203   // Emit the remarks section contents.
2204   // FIXME: Figure out when is the safest time to emit this section. It should
2205   // not come after debug info.
2206   if (remarks::RemarkStreamer *RS = M.getContext().getMainRemarkStreamer())
2207     emitRemarksSection(*RS);
2208 
2209   TLOF.emitModuleMetadata(*OutStreamer, M);
2210 
2211   if (TM.getTargetTriple().isOSBinFormatELF()) {
2212     MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
2213 
2214     // Output stubs for external and common global variables.
2215     MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
2216     if (!Stubs.empty()) {
2217       OutStreamer->switchSection(TLOF.getDataSection());
2218       const DataLayout &DL = M.getDataLayout();
2219 
2220       emitAlignment(Align(DL.getPointerSize()));
2221       for (const auto &Stub : Stubs) {
2222         OutStreamer->emitLabel(Stub.first);
2223         OutStreamer->emitSymbolValue(Stub.second.getPointer(),
2224                                      DL.getPointerSize());
2225       }
2226     }
2227   }
2228 
2229   if (TM.getTargetTriple().isOSBinFormatCOFF()) {
2230     MachineModuleInfoCOFF &MMICOFF =
2231         MMI->getObjFileInfo<MachineModuleInfoCOFF>();
2232 
2233     // Output stubs for external and common global variables.
2234     MachineModuleInfoCOFF::SymbolListTy Stubs = MMICOFF.GetGVStubList();
2235     if (!Stubs.empty()) {
2236       const DataLayout &DL = M.getDataLayout();
2237 
2238       for (const auto &Stub : Stubs) {
2239         SmallString<256> SectionName = StringRef(".rdata$");
2240         SectionName += Stub.first->getName();
2241         OutStreamer->switchSection(OutContext.getCOFFSection(
2242             SectionName,
2243             COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
2244                 COFF::IMAGE_SCN_LNK_COMDAT,
2245             SectionKind::getReadOnly(), Stub.first->getName(),
2246             COFF::IMAGE_COMDAT_SELECT_ANY));
2247         emitAlignment(Align(DL.getPointerSize()));
2248         OutStreamer->emitSymbolAttribute(Stub.first, MCSA_Global);
2249         OutStreamer->emitLabel(Stub.first);
2250         OutStreamer->emitSymbolValue(Stub.second.getPointer(),
2251                                      DL.getPointerSize());
2252       }
2253     }
2254   }
2255 
2256   // This needs to happen before emitting debug information since that can end
2257   // arbitrary sections.
2258   if (auto *TS = OutStreamer->getTargetStreamer())
2259     TS->emitConstantPools();
2260 
2261   // Emit Stack maps before any debug info. Mach-O requires that no data or
2262   // text sections come after debug info has been emitted. This matters for
2263   // stack maps as they are arbitrary data, and may even have a custom format
2264   // through user plugins.
2265   emitStackMaps();
2266 
2267   // Finalize debug and EH information.
2268   for (const HandlerInfo &HI : Handlers) {
2269     NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
2270                        HI.TimerGroupDescription, TimePassesIsEnabled);
2271     HI.Handler->endModule();
2272   }
2273 
2274   // This deletes all the ephemeral handlers that AsmPrinter added, while
2275   // keeping all the user-added handlers alive until the AsmPrinter is
2276   // destroyed.
2277   Handlers.erase(Handlers.begin() + NumUserHandlers, Handlers.end());
2278   DD = nullptr;
2279 
2280   // If the target wants to know about weak references, print them all.
2281   if (MAI->getWeakRefDirective()) {
2282     // FIXME: This is not lazy, it would be nice to only print weak references
2283     // to stuff that is actually used.  Note that doing so would require targets
2284     // to notice uses in operands (due to constant exprs etc).  This should
2285     // happen with the MC stuff eventually.
2286 
2287     // Print out module-level global objects here.
2288     for (const auto &GO : M.global_objects()) {
2289       if (!GO.hasExternalWeakLinkage())
2290         continue;
2291       OutStreamer->emitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
2292     }
2293     if (shouldEmitWeakSwiftAsyncExtendedFramePointerFlags()) {
2294       auto SymbolName = "swift_async_extendedFramePointerFlags";
2295       auto Global = M.getGlobalVariable(SymbolName);
2296       if (!Global) {
2297         auto Int8PtrTy = Type::getInt8PtrTy(M.getContext());
2298         Global = new GlobalVariable(M, Int8PtrTy, false,
2299                                     GlobalValue::ExternalWeakLinkage, nullptr,
2300                                     SymbolName);
2301         OutStreamer->emitSymbolAttribute(getSymbol(Global), MCSA_WeakReference);
2302       }
2303     }
2304   }
2305 
2306   // Print aliases in topological order, that is, for each alias a = b,
2307   // b must be printed before a.
2308   // This is because on some targets (e.g. PowerPC) linker expects aliases in
2309   // such an order to generate correct TOC information.
2310   SmallVector<const GlobalAlias *, 16> AliasStack;
2311   SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
2312   for (const auto &Alias : M.aliases()) {
2313     if (Alias.hasAvailableExternallyLinkage())
2314       continue;
2315     for (const GlobalAlias *Cur = &Alias; Cur;
2316          Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
2317       if (!AliasVisited.insert(Cur).second)
2318         break;
2319       AliasStack.push_back(Cur);
2320     }
2321     for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
2322       emitGlobalAlias(M, *AncestorAlias);
2323     AliasStack.clear();
2324   }
2325   for (const auto &IFunc : M.ifuncs())
2326     emitGlobalIFunc(M, IFunc);
2327 
2328   GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
2329   assert(MI && "AsmPrinter didn't require GCModuleInfo?");
2330   for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
2331     if (GCMetadataPrinter *MP = getOrCreateGCPrinter(**--I))
2332       MP->finishAssembly(M, *MI, *this);
2333 
2334   // Emit llvm.ident metadata in an '.ident' directive.
2335   emitModuleIdents(M);
2336 
2337   // Emit bytes for llvm.commandline metadata.
2338   // The command line metadata is emitted earlier on XCOFF.
2339   if (!TM.getTargetTriple().isOSBinFormatXCOFF())
2340     emitModuleCommandLines(M);
2341 
2342   // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if
2343   // split-stack is used.
2344   if (TM.getTargetTriple().isOSBinFormatELF() && HasSplitStack) {
2345     OutStreamer->switchSection(OutContext.getELFSection(".note.GNU-split-stack",
2346                                                         ELF::SHT_PROGBITS, 0));
2347     if (HasNoSplitStack)
2348       OutStreamer->switchSection(OutContext.getELFSection(
2349           ".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0));
2350   }
2351 
2352   // If we don't have any trampolines, then we don't require stack memory
2353   // to be executable. Some targets have a directive to declare this.
2354   Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
2355   if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
2356     if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
2357       OutStreamer->switchSection(S);
2358 
2359   if (TM.Options.EmitAddrsig) {
2360     // Emit address-significance attributes for all globals.
2361     OutStreamer->emitAddrsig();
2362     for (const GlobalValue &GV : M.global_values()) {
2363       if (!GV.use_empty() && !GV.isThreadLocal() &&
2364           !GV.hasDLLImportStorageClass() && !GV.getName().startswith("llvm.") &&
2365           !GV.hasAtLeastLocalUnnamedAddr())
2366         OutStreamer->emitAddrsigSym(getSymbol(&GV));
2367     }
2368   }
2369 
2370   // Emit symbol partition specifications (ELF only).
2371   if (TM.getTargetTriple().isOSBinFormatELF()) {
2372     unsigned UniqueID = 0;
2373     for (const GlobalValue &GV : M.global_values()) {
2374       if (!GV.hasPartition() || GV.isDeclarationForLinker() ||
2375           GV.getVisibility() != GlobalValue::DefaultVisibility)
2376         continue;
2377 
2378       OutStreamer->switchSection(
2379           OutContext.getELFSection(".llvm_sympart", ELF::SHT_LLVM_SYMPART, 0, 0,
2380                                    "", false, ++UniqueID, nullptr));
2381       OutStreamer->emitBytes(GV.getPartition());
2382       OutStreamer->emitZeros(1);
2383       OutStreamer->emitValue(
2384           MCSymbolRefExpr::create(getSymbol(&GV), OutContext),
2385           MAI->getCodePointerSize());
2386     }
2387   }
2388 
2389   // Allow the target to emit any magic that it wants at the end of the file,
2390   // after everything else has gone out.
2391   emitEndOfAsmFile(M);
2392 
2393   MMI = nullptr;
2394   AddrLabelSymbols = nullptr;
2395 
2396   OutStreamer->finish();
2397   OutStreamer->reset();
2398   OwnedMLI.reset();
2399   OwnedMDT.reset();
2400 
2401   return false;
2402 }
2403 
2404 MCSymbol *AsmPrinter::getMBBExceptionSym(const MachineBasicBlock &MBB) {
2405   auto Res = MBBSectionExceptionSyms.try_emplace(MBB.getSectionIDNum());
2406   if (Res.second)
2407     Res.first->second = createTempSymbol("exception");
2408   return Res.first->second;
2409 }
2410 
2411 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
2412   this->MF = &MF;
2413   const Function &F = MF.getFunction();
2414 
2415   // Record that there are split-stack functions, so we will emit a special
2416   // section to tell the linker.
2417   if (MF.shouldSplitStack()) {
2418     HasSplitStack = true;
2419 
2420     if (!MF.getFrameInfo().needsSplitStackProlog())
2421       HasNoSplitStack = true;
2422   } else
2423     HasNoSplitStack = true;
2424 
2425   // Get the function symbol.
2426   if (!MAI->needsFunctionDescriptors()) {
2427     CurrentFnSym = getSymbol(&MF.getFunction());
2428   } else {
2429     assert(TM.getTargetTriple().isOSAIX() &&
2430            "Only AIX uses the function descriptor hooks.");
2431     // AIX is unique here in that the name of the symbol emitted for the
2432     // function body does not have the same name as the source function's
2433     // C-linkage name.
2434     assert(CurrentFnDescSym && "The function descriptor symbol needs to be"
2435                                " initalized first.");
2436 
2437     // Get the function entry point symbol.
2438     CurrentFnSym = getObjFileLowering().getFunctionEntryPointSymbol(&F, TM);
2439   }
2440 
2441   CurrentFnSymForSize = CurrentFnSym;
2442   CurrentFnBegin = nullptr;
2443   CurrentFnBeginLocal = nullptr;
2444   CurrentSectionBeginSym = nullptr;
2445   MBBSectionRanges.clear();
2446   MBBSectionExceptionSyms.clear();
2447   bool NeedsLocalForSize = MAI->needsLocalForSize();
2448   if (F.hasFnAttribute("patchable-function-entry") ||
2449       F.hasFnAttribute("function-instrument") ||
2450       F.hasFnAttribute("xray-instruction-threshold") ||
2451       needFuncLabels(MF) || NeedsLocalForSize ||
2452       MF.getTarget().Options.EmitStackSizeSection || MF.hasBBLabels()) {
2453     CurrentFnBegin = createTempSymbol("func_begin");
2454     if (NeedsLocalForSize)
2455       CurrentFnSymForSize = CurrentFnBegin;
2456   }
2457 
2458   ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
2459 }
2460 
2461 namespace {
2462 
2463 // Keep track the alignment, constpool entries per Section.
2464   struct SectionCPs {
2465     MCSection *S;
2466     Align Alignment;
2467     SmallVector<unsigned, 4> CPEs;
2468 
2469     SectionCPs(MCSection *s, Align a) : S(s), Alignment(a) {}
2470   };
2471 
2472 } // end anonymous namespace
2473 
2474 /// EmitConstantPool - Print to the current output stream assembly
2475 /// representations of the constants in the constant pool MCP. This is
2476 /// used to print out constants which have been "spilled to memory" by
2477 /// the code generator.
2478 void AsmPrinter::emitConstantPool() {
2479   const MachineConstantPool *MCP = MF->getConstantPool();
2480   const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
2481   if (CP.empty()) return;
2482 
2483   // Calculate sections for constant pool entries. We collect entries to go into
2484   // the same section together to reduce amount of section switch statements.
2485   SmallVector<SectionCPs, 4> CPSections;
2486   for (unsigned i = 0, e = CP.size(); i != e; ++i) {
2487     const MachineConstantPoolEntry &CPE = CP[i];
2488     Align Alignment = CPE.getAlign();
2489 
2490     SectionKind Kind = CPE.getSectionKind(&getDataLayout());
2491 
2492     const Constant *C = nullptr;
2493     if (!CPE.isMachineConstantPoolEntry())
2494       C = CPE.Val.ConstVal;
2495 
2496     MCSection *S = getObjFileLowering().getSectionForConstant(
2497         getDataLayout(), Kind, C, Alignment);
2498 
2499     // The number of sections are small, just do a linear search from the
2500     // last section to the first.
2501     bool Found = false;
2502     unsigned SecIdx = CPSections.size();
2503     while (SecIdx != 0) {
2504       if (CPSections[--SecIdx].S == S) {
2505         Found = true;
2506         break;
2507       }
2508     }
2509     if (!Found) {
2510       SecIdx = CPSections.size();
2511       CPSections.push_back(SectionCPs(S, Alignment));
2512     }
2513 
2514     if (Alignment > CPSections[SecIdx].Alignment)
2515       CPSections[SecIdx].Alignment = Alignment;
2516     CPSections[SecIdx].CPEs.push_back(i);
2517   }
2518 
2519   // Now print stuff into the calculated sections.
2520   const MCSection *CurSection = nullptr;
2521   unsigned Offset = 0;
2522   for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
2523     for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
2524       unsigned CPI = CPSections[i].CPEs[j];
2525       MCSymbol *Sym = GetCPISymbol(CPI);
2526       if (!Sym->isUndefined())
2527         continue;
2528 
2529       if (CurSection != CPSections[i].S) {
2530         OutStreamer->switchSection(CPSections[i].S);
2531         emitAlignment(Align(CPSections[i].Alignment));
2532         CurSection = CPSections[i].S;
2533         Offset = 0;
2534       }
2535 
2536       MachineConstantPoolEntry CPE = CP[CPI];
2537 
2538       // Emit inter-object padding for alignment.
2539       unsigned NewOffset = alignTo(Offset, CPE.getAlign());
2540       OutStreamer->emitZeros(NewOffset - Offset);
2541 
2542       Offset = NewOffset + CPE.getSizeInBytes(getDataLayout());
2543 
2544       OutStreamer->emitLabel(Sym);
2545       if (CPE.isMachineConstantPoolEntry())
2546         emitMachineConstantPoolValue(CPE.Val.MachineCPVal);
2547       else
2548         emitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
2549     }
2550   }
2551 }
2552 
2553 // Print assembly representations of the jump tables used by the current
2554 // function.
2555 void AsmPrinter::emitJumpTableInfo() {
2556   const DataLayout &DL = MF->getDataLayout();
2557   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
2558   if (!MJTI) return;
2559   if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
2560   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
2561   if (JT.empty()) return;
2562 
2563   // Pick the directive to use to print the jump table entries, and switch to
2564   // the appropriate section.
2565   const Function &F = MF->getFunction();
2566   const TargetLoweringObjectFile &TLOF = getObjFileLowering();
2567   bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
2568       MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
2569       F);
2570   if (JTInDiffSection) {
2571     // Drop it in the readonly section.
2572     MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM);
2573     OutStreamer->switchSection(ReadOnlySection);
2574   }
2575 
2576   emitAlignment(Align(MJTI->getEntryAlignment(DL)));
2577 
2578   // Jump tables in code sections are marked with a data_region directive
2579   // where that's supported.
2580   if (!JTInDiffSection)
2581     OutStreamer->emitDataRegion(MCDR_DataRegionJT32);
2582 
2583   for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
2584     const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
2585 
2586     // If this jump table was deleted, ignore it.
2587     if (JTBBs.empty()) continue;
2588 
2589     // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
2590     /// emit a .set directive for each unique entry.
2591     if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
2592         MAI->doesSetDirectiveSuppressReloc()) {
2593       SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
2594       const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
2595       const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
2596       for (const MachineBasicBlock *MBB : JTBBs) {
2597         if (!EmittedSets.insert(MBB).second)
2598           continue;
2599 
2600         // .set LJTSet, LBB32-base
2601         const MCExpr *LHS =
2602           MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
2603         OutStreamer->emitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
2604                                     MCBinaryExpr::createSub(LHS, Base,
2605                                                             OutContext));
2606       }
2607     }
2608 
2609     // On some targets (e.g. Darwin) we want to emit two consecutive labels
2610     // before each jump table.  The first label is never referenced, but tells
2611     // the assembler and linker the extents of the jump table object.  The
2612     // second label is actually referenced by the code.
2613     if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
2614       // FIXME: This doesn't have to have any specific name, just any randomly
2615       // named and numbered local label started with 'l' would work.  Simplify
2616       // GetJTISymbol.
2617       OutStreamer->emitLabel(GetJTISymbol(JTI, true));
2618 
2619     MCSymbol* JTISymbol = GetJTISymbol(JTI);
2620     OutStreamer->emitLabel(JTISymbol);
2621 
2622     for (const MachineBasicBlock *MBB : JTBBs)
2623       emitJumpTableEntry(MJTI, MBB, JTI);
2624   }
2625   if (!JTInDiffSection)
2626     OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
2627 }
2628 
2629 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
2630 /// current stream.
2631 void AsmPrinter::emitJumpTableEntry(const MachineJumpTableInfo *MJTI,
2632                                     const MachineBasicBlock *MBB,
2633                                     unsigned UID) const {
2634   assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
2635   const MCExpr *Value = nullptr;
2636   switch (MJTI->getEntryKind()) {
2637   case MachineJumpTableInfo::EK_Inline:
2638     llvm_unreachable("Cannot emit EK_Inline jump table entry");
2639   case MachineJumpTableInfo::EK_Custom32:
2640     Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
2641         MJTI, MBB, UID, OutContext);
2642     break;
2643   case MachineJumpTableInfo::EK_BlockAddress:
2644     // EK_BlockAddress - Each entry is a plain address of block, e.g.:
2645     //     .word LBB123
2646     Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
2647     break;
2648   case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
2649     // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
2650     // with a relocation as gp-relative, e.g.:
2651     //     .gprel32 LBB123
2652     MCSymbol *MBBSym = MBB->getSymbol();
2653     OutStreamer->emitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
2654     return;
2655   }
2656 
2657   case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
2658     // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
2659     // with a relocation as gp-relative, e.g.:
2660     //     .gpdword LBB123
2661     MCSymbol *MBBSym = MBB->getSymbol();
2662     OutStreamer->emitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
2663     return;
2664   }
2665 
2666   case MachineJumpTableInfo::EK_LabelDifference32: {
2667     // Each entry is the address of the block minus the address of the jump
2668     // table. This is used for PIC jump tables where gprel32 is not supported.
2669     // e.g.:
2670     //      .word LBB123 - LJTI1_2
2671     // If the .set directive avoids relocations, this is emitted as:
2672     //      .set L4_5_set_123, LBB123 - LJTI1_2
2673     //      .word L4_5_set_123
2674     if (MAI->doesSetDirectiveSuppressReloc()) {
2675       Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
2676                                       OutContext);
2677       break;
2678     }
2679     Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
2680     const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
2681     const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
2682     Value = MCBinaryExpr::createSub(Value, Base, OutContext);
2683     break;
2684   }
2685   }
2686 
2687   assert(Value && "Unknown entry kind!");
2688 
2689   unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
2690   OutStreamer->emitValue(Value, EntrySize);
2691 }
2692 
2693 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
2694 /// special global used by LLVM.  If so, emit it and return true, otherwise
2695 /// do nothing and return false.
2696 bool AsmPrinter::emitSpecialLLVMGlobal(const GlobalVariable *GV) {
2697   if (GV->getName() == "llvm.used") {
2698     if (MAI->hasNoDeadStrip())    // No need to emit this at all.
2699       emitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
2700     return true;
2701   }
2702 
2703   // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
2704   if (GV->getSection() == "llvm.metadata" ||
2705       GV->hasAvailableExternallyLinkage())
2706     return true;
2707 
2708   if (!GV->hasAppendingLinkage()) return false;
2709 
2710   assert(GV->hasInitializer() && "Not a special LLVM global!");
2711 
2712   if (GV->getName() == "llvm.global_ctors") {
2713     emitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
2714                        /* isCtor */ true);
2715 
2716     return true;
2717   }
2718 
2719   if (GV->getName() == "llvm.global_dtors") {
2720     emitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
2721                        /* isCtor */ false);
2722 
2723     return true;
2724   }
2725 
2726   report_fatal_error("unknown special variable");
2727 }
2728 
2729 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
2730 /// global in the specified llvm.used list.
2731 void AsmPrinter::emitLLVMUsedList(const ConstantArray *InitList) {
2732   // Should be an array of 'i8*'.
2733   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
2734     const GlobalValue *GV =
2735       dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
2736     if (GV)
2737       OutStreamer->emitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
2738   }
2739 }
2740 
2741 void AsmPrinter::preprocessXXStructorList(const DataLayout &DL,
2742                                           const Constant *List,
2743                                           SmallVector<Structor, 8> &Structors) {
2744   // Should be an array of '{ i32, void ()*, i8* }' structs.  The first value is
2745   // the init priority.
2746   if (!isa<ConstantArray>(List))
2747     return;
2748 
2749   // Gather the structors in a form that's convenient for sorting by priority.
2750   for (Value *O : cast<ConstantArray>(List)->operands()) {
2751     auto *CS = cast<ConstantStruct>(O);
2752     if (CS->getOperand(1)->isNullValue())
2753       break; // Found a null terminator, skip the rest.
2754     ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
2755     if (!Priority)
2756       continue; // Malformed.
2757     Structors.push_back(Structor());
2758     Structor &S = Structors.back();
2759     S.Priority = Priority->getLimitedValue(65535);
2760     S.Func = CS->getOperand(1);
2761     if (!CS->getOperand(2)->isNullValue()) {
2762       if (TM.getTargetTriple().isOSAIX())
2763         llvm::report_fatal_error(
2764             "associated data of XXStructor list is not yet supported on AIX");
2765       S.ComdatKey =
2766           dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
2767     }
2768   }
2769 
2770   // Emit the function pointers in the target-specific order
2771   llvm::stable_sort(Structors, [](const Structor &L, const Structor &R) {
2772     return L.Priority < R.Priority;
2773   });
2774 }
2775 
2776 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
2777 /// priority.
2778 void AsmPrinter::emitXXStructorList(const DataLayout &DL, const Constant *List,
2779                                     bool IsCtor) {
2780   SmallVector<Structor, 8> Structors;
2781   preprocessXXStructorList(DL, List, Structors);
2782   if (Structors.empty())
2783     return;
2784 
2785   // Emit the structors in reverse order if we are using the .ctor/.dtor
2786   // initialization scheme.
2787   if (!TM.Options.UseInitArray)
2788     std::reverse(Structors.begin(), Structors.end());
2789 
2790   const Align Align = DL.getPointerPrefAlignment();
2791   for (Structor &S : Structors) {
2792     const TargetLoweringObjectFile &Obj = getObjFileLowering();
2793     const MCSymbol *KeySym = nullptr;
2794     if (GlobalValue *GV = S.ComdatKey) {
2795       if (GV->isDeclarationForLinker())
2796         // If the associated variable is not defined in this module
2797         // (it might be available_externally, or have been an
2798         // available_externally definition that was dropped by the
2799         // EliminateAvailableExternally pass), some other TU
2800         // will provide its dynamic initializer.
2801         continue;
2802 
2803       KeySym = getSymbol(GV);
2804     }
2805 
2806     MCSection *OutputSection =
2807         (IsCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
2808                 : Obj.getStaticDtorSection(S.Priority, KeySym));
2809     OutStreamer->switchSection(OutputSection);
2810     if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
2811       emitAlignment(Align);
2812     emitXXStructor(DL, S.Func);
2813   }
2814 }
2815 
2816 void AsmPrinter::emitModuleIdents(Module &M) {
2817   if (!MAI->hasIdentDirective())
2818     return;
2819 
2820   if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
2821     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
2822       const MDNode *N = NMD->getOperand(i);
2823       assert(N->getNumOperands() == 1 &&
2824              "llvm.ident metadata entry can have only one operand");
2825       const MDString *S = cast<MDString>(N->getOperand(0));
2826       OutStreamer->emitIdent(S->getString());
2827     }
2828   }
2829 }
2830 
2831 void AsmPrinter::emitModuleCommandLines(Module &M) {
2832   MCSection *CommandLine = getObjFileLowering().getSectionForCommandLines();
2833   if (!CommandLine)
2834     return;
2835 
2836   const NamedMDNode *NMD = M.getNamedMetadata("llvm.commandline");
2837   if (!NMD || !NMD->getNumOperands())
2838     return;
2839 
2840   OutStreamer->pushSection();
2841   OutStreamer->switchSection(CommandLine);
2842   OutStreamer->emitZeros(1);
2843   for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
2844     const MDNode *N = NMD->getOperand(i);
2845     assert(N->getNumOperands() == 1 &&
2846            "llvm.commandline metadata entry can have only one operand");
2847     const MDString *S = cast<MDString>(N->getOperand(0));
2848     OutStreamer->emitBytes(S->getString());
2849     OutStreamer->emitZeros(1);
2850   }
2851   OutStreamer->popSection();
2852 }
2853 
2854 //===--------------------------------------------------------------------===//
2855 // Emission and print routines
2856 //
2857 
2858 /// Emit a byte directive and value.
2859 ///
2860 void AsmPrinter::emitInt8(int Value) const { OutStreamer->emitInt8(Value); }
2861 
2862 /// Emit a short directive and value.
2863 void AsmPrinter::emitInt16(int Value) const { OutStreamer->emitInt16(Value); }
2864 
2865 /// Emit a long directive and value.
2866 void AsmPrinter::emitInt32(int Value) const { OutStreamer->emitInt32(Value); }
2867 
2868 /// EmitSLEB128 - emit the specified signed leb128 value.
2869 void AsmPrinter::emitSLEB128(int64_t Value, const char *Desc) const {
2870   if (isVerbose() && Desc)
2871     OutStreamer->AddComment(Desc);
2872 
2873   OutStreamer->emitSLEB128IntValue(Value);
2874 }
2875 
2876 void AsmPrinter::emitULEB128(uint64_t Value, const char *Desc,
2877                              unsigned PadTo) const {
2878   if (isVerbose() && Desc)
2879     OutStreamer->AddComment(Desc);
2880 
2881   OutStreamer->emitULEB128IntValue(Value, PadTo);
2882 }
2883 
2884 /// Emit a long long directive and value.
2885 void AsmPrinter::emitInt64(uint64_t Value) const {
2886   OutStreamer->emitInt64(Value);
2887 }
2888 
2889 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
2890 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
2891 /// .set if it avoids relocations.
2892 void AsmPrinter::emitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
2893                                      unsigned Size) const {
2894   OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
2895 }
2896 
2897 /// Emit something like ".uleb128 Hi-Lo".
2898 void AsmPrinter::emitLabelDifferenceAsULEB128(const MCSymbol *Hi,
2899                                               const MCSymbol *Lo) const {
2900   OutStreamer->emitAbsoluteSymbolDiffAsULEB128(Hi, Lo);
2901 }
2902 
2903 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
2904 /// where the size in bytes of the directive is specified by Size and Label
2905 /// specifies the label.  This implicitly uses .set if it is available.
2906 void AsmPrinter::emitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
2907                                      unsigned Size,
2908                                      bool IsSectionRelative) const {
2909   if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
2910     OutStreamer->emitCOFFSecRel32(Label, Offset);
2911     if (Size > 4)
2912       OutStreamer->emitZeros(Size - 4);
2913     return;
2914   }
2915 
2916   // Emit Label+Offset (or just Label if Offset is zero)
2917   const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
2918   if (Offset)
2919     Expr = MCBinaryExpr::createAdd(
2920         Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
2921 
2922   OutStreamer->emitValue(Expr, Size);
2923 }
2924 
2925 //===----------------------------------------------------------------------===//
2926 
2927 // EmitAlignment - Emit an alignment directive to the specified power of
2928 // two boundary.  If a global value is specified, and if that global has
2929 // an explicit alignment requested, it will override the alignment request
2930 // if required for correctness.
2931 void AsmPrinter::emitAlignment(Align Alignment, const GlobalObject *GV,
2932                                unsigned MaxBytesToEmit) const {
2933   if (GV)
2934     Alignment = getGVAlignment(GV, GV->getParent()->getDataLayout(), Alignment);
2935 
2936   if (Alignment == Align(1))
2937     return; // 1-byte aligned: no need to emit alignment.
2938 
2939   if (getCurrentSection()->getKind().isText()) {
2940     const MCSubtargetInfo *STI = nullptr;
2941     if (this->MF)
2942       STI = &getSubtargetInfo();
2943     else
2944       STI = TM.getMCSubtargetInfo();
2945     OutStreamer->emitCodeAlignment(Alignment, STI, MaxBytesToEmit);
2946   } else
2947     OutStreamer->emitValueToAlignment(Alignment, 0, 1, MaxBytesToEmit);
2948 }
2949 
2950 //===----------------------------------------------------------------------===//
2951 // Constant emission.
2952 //===----------------------------------------------------------------------===//
2953 
2954 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
2955   MCContext &Ctx = OutContext;
2956 
2957   if (CV->isNullValue() || isa<UndefValue>(CV))
2958     return MCConstantExpr::create(0, Ctx);
2959 
2960   if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
2961     return MCConstantExpr::create(CI->getZExtValue(), Ctx);
2962 
2963   if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
2964     return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
2965 
2966   if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
2967     return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
2968 
2969   if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(CV))
2970     return getObjFileLowering().lowerDSOLocalEquivalent(Equiv, TM);
2971 
2972   if (const NoCFIValue *NC = dyn_cast<NoCFIValue>(CV))
2973     return MCSymbolRefExpr::create(getSymbol(NC->getGlobalValue()), Ctx);
2974 
2975   const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
2976   if (!CE) {
2977     llvm_unreachable("Unknown constant value to lower!");
2978   }
2979 
2980   // The constant expression opcodes are limited to those that are necessary
2981   // to represent relocations on supported targets. Expressions involving only
2982   // constant addresses are constant folded instead.
2983   switch (CE->getOpcode()) {
2984   default:
2985     break; // Error
2986   case Instruction::AddrSpaceCast: {
2987     const Constant *Op = CE->getOperand(0);
2988     unsigned DstAS = CE->getType()->getPointerAddressSpace();
2989     unsigned SrcAS = Op->getType()->getPointerAddressSpace();
2990     if (TM.isNoopAddrSpaceCast(SrcAS, DstAS))
2991       return lowerConstant(Op);
2992 
2993     break; // Error
2994   }
2995   case Instruction::GetElementPtr: {
2996     // Generate a symbolic expression for the byte address
2997     APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
2998     cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
2999 
3000     const MCExpr *Base = lowerConstant(CE->getOperand(0));
3001     if (!OffsetAI)
3002       return Base;
3003 
3004     int64_t Offset = OffsetAI.getSExtValue();
3005     return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
3006                                    Ctx);
3007   }
3008 
3009   case Instruction::Trunc:
3010     // We emit the value and depend on the assembler to truncate the generated
3011     // expression properly.  This is important for differences between
3012     // blockaddress labels.  Since the two labels are in the same function, it
3013     // is reasonable to treat their delta as a 32-bit value.
3014     [[fallthrough]];
3015   case Instruction::BitCast:
3016     return lowerConstant(CE->getOperand(0));
3017 
3018   case Instruction::IntToPtr: {
3019     const DataLayout &DL = getDataLayout();
3020 
3021     // Handle casts to pointers by changing them into casts to the appropriate
3022     // integer type.  This promotes constant folding and simplifies this code.
3023     Constant *Op = CE->getOperand(0);
3024     Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
3025                                       false/*ZExt*/);
3026     return lowerConstant(Op);
3027   }
3028 
3029   case Instruction::PtrToInt: {
3030     const DataLayout &DL = getDataLayout();
3031 
3032     // Support only foldable casts to/from pointers that can be eliminated by
3033     // changing the pointer to the appropriately sized integer type.
3034     Constant *Op = CE->getOperand(0);
3035     Type *Ty = CE->getType();
3036 
3037     const MCExpr *OpExpr = lowerConstant(Op);
3038 
3039     // We can emit the pointer value into this slot if the slot is an
3040     // integer slot equal to the size of the pointer.
3041     //
3042     // If the pointer is larger than the resultant integer, then
3043     // as with Trunc just depend on the assembler to truncate it.
3044     if (DL.getTypeAllocSize(Ty).getFixedValue() <=
3045         DL.getTypeAllocSize(Op->getType()).getFixedValue())
3046       return OpExpr;
3047 
3048     break; // Error
3049   }
3050 
3051   case Instruction::Sub: {
3052     GlobalValue *LHSGV;
3053     APInt LHSOffset;
3054     DSOLocalEquivalent *DSOEquiv;
3055     if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
3056                                    getDataLayout(), &DSOEquiv)) {
3057       GlobalValue *RHSGV;
3058       APInt RHSOffset;
3059       if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
3060                                      getDataLayout())) {
3061         const MCExpr *RelocExpr =
3062             getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM);
3063         if (!RelocExpr) {
3064           const MCExpr *LHSExpr =
3065               MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx);
3066           if (DSOEquiv &&
3067               getObjFileLowering().supportDSOLocalEquivalentLowering())
3068             LHSExpr =
3069                 getObjFileLowering().lowerDSOLocalEquivalent(DSOEquiv, TM);
3070           RelocExpr = MCBinaryExpr::createSub(
3071               LHSExpr, MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
3072         }
3073         int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
3074         if (Addend != 0)
3075           RelocExpr = MCBinaryExpr::createAdd(
3076               RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
3077         return RelocExpr;
3078       }
3079     }
3080 
3081     const MCExpr *LHS = lowerConstant(CE->getOperand(0));
3082     const MCExpr *RHS = lowerConstant(CE->getOperand(1));
3083     return MCBinaryExpr::createSub(LHS, RHS, Ctx);
3084     break;
3085   }
3086 
3087   case Instruction::Add: {
3088     const MCExpr *LHS = lowerConstant(CE->getOperand(0));
3089     const MCExpr *RHS = lowerConstant(CE->getOperand(1));
3090     return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
3091   }
3092   }
3093 
3094   // If the code isn't optimized, there may be outstanding folding
3095   // opportunities. Attempt to fold the expression using DataLayout as a
3096   // last resort before giving up.
3097   Constant *C = ConstantFoldConstant(CE, getDataLayout());
3098   if (C != CE)
3099     return lowerConstant(C);
3100 
3101   // Otherwise report the problem to the user.
3102   std::string S;
3103   raw_string_ostream OS(S);
3104   OS << "Unsupported expression in static initializer: ";
3105   CE->printAsOperand(OS, /*PrintType=*/false,
3106                      !MF ? nullptr : MF->getFunction().getParent());
3107   report_fatal_error(Twine(OS.str()));
3108 }
3109 
3110 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
3111                                    AsmPrinter &AP,
3112                                    const Constant *BaseCV = nullptr,
3113                                    uint64_t Offset = 0,
3114                                    AsmPrinter::AliasMapTy *AliasList = nullptr);
3115 
3116 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
3117 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP);
3118 
3119 /// isRepeatedByteSequence - Determine whether the given value is
3120 /// composed of a repeated sequence of identical bytes and return the
3121 /// byte value.  If it is not a repeated sequence, return -1.
3122 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
3123   StringRef Data = V->getRawDataValues();
3124   assert(!Data.empty() && "Empty aggregates should be CAZ node");
3125   char C = Data[0];
3126   for (unsigned i = 1, e = Data.size(); i != e; ++i)
3127     if (Data[i] != C) return -1;
3128   return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
3129 }
3130 
3131 /// isRepeatedByteSequence - Determine whether the given value is
3132 /// composed of a repeated sequence of identical bytes and return the
3133 /// byte value.  If it is not a repeated sequence, return -1.
3134 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
3135   if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
3136     uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
3137     assert(Size % 8 == 0);
3138 
3139     // Extend the element to take zero padding into account.
3140     APInt Value = CI->getValue().zext(Size);
3141     if (!Value.isSplat(8))
3142       return -1;
3143 
3144     return Value.zextOrTrunc(8).getZExtValue();
3145   }
3146   if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
3147     // Make sure all array elements are sequences of the same repeated
3148     // byte.
3149     assert(CA->getNumOperands() != 0 && "Should be a CAZ");
3150     Constant *Op0 = CA->getOperand(0);
3151     int Byte = isRepeatedByteSequence(Op0, DL);
3152     if (Byte == -1)
3153       return -1;
3154 
3155     // All array elements must be equal.
3156     for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
3157       if (CA->getOperand(i) != Op0)
3158         return -1;
3159     return Byte;
3160   }
3161 
3162   if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
3163     return isRepeatedByteSequence(CDS);
3164 
3165   return -1;
3166 }
3167 
3168 static void emitGlobalAliasInline(AsmPrinter &AP, uint64_t Offset,
3169                                   AsmPrinter::AliasMapTy *AliasList) {
3170   if (AliasList) {
3171     auto AliasIt = AliasList->find(Offset);
3172     if (AliasIt != AliasList->end()) {
3173       for (const GlobalAlias *GA : AliasIt->second)
3174         AP.OutStreamer->emitLabel(AP.getSymbol(GA));
3175       AliasList->erase(Offset);
3176     }
3177   }
3178 }
3179 
3180 static void emitGlobalConstantDataSequential(
3181     const DataLayout &DL, const ConstantDataSequential *CDS, AsmPrinter &AP,
3182     AsmPrinter::AliasMapTy *AliasList) {
3183   // See if we can aggregate this into a .fill, if so, emit it as such.
3184   int Value = isRepeatedByteSequence(CDS, DL);
3185   if (Value != -1) {
3186     uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
3187     // Don't emit a 1-byte object as a .fill.
3188     if (Bytes > 1)
3189       return AP.OutStreamer->emitFill(Bytes, Value);
3190   }
3191 
3192   // If this can be emitted with .ascii/.asciz, emit it as such.
3193   if (CDS->isString())
3194     return AP.OutStreamer->emitBytes(CDS->getAsString());
3195 
3196   // Otherwise, emit the values in successive locations.
3197   unsigned ElementByteSize = CDS->getElementByteSize();
3198   if (isa<IntegerType>(CDS->getElementType())) {
3199     for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I) {
3200       emitGlobalAliasInline(AP, ElementByteSize * I, AliasList);
3201       if (AP.isVerbose())
3202         AP.OutStreamer->getCommentOS()
3203             << format("0x%" PRIx64 "\n", CDS->getElementAsInteger(I));
3204       AP.OutStreamer->emitIntValue(CDS->getElementAsInteger(I),
3205                                    ElementByteSize);
3206     }
3207   } else {
3208     Type *ET = CDS->getElementType();
3209     for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I) {
3210       emitGlobalAliasInline(AP, ElementByteSize * I, AliasList);
3211       emitGlobalConstantFP(CDS->getElementAsAPFloat(I), ET, AP);
3212     }
3213   }
3214 
3215   unsigned Size = DL.getTypeAllocSize(CDS->getType());
3216   unsigned EmittedSize =
3217       DL.getTypeAllocSize(CDS->getElementType()) * CDS->getNumElements();
3218   assert(EmittedSize <= Size && "Size cannot be less than EmittedSize!");
3219   if (unsigned Padding = Size - EmittedSize)
3220     AP.OutStreamer->emitZeros(Padding);
3221 }
3222 
3223 static void emitGlobalConstantArray(const DataLayout &DL,
3224                                     const ConstantArray *CA, AsmPrinter &AP,
3225                                     const Constant *BaseCV, uint64_t Offset,
3226                                     AsmPrinter::AliasMapTy *AliasList) {
3227   // See if we can aggregate some values.  Make sure it can be
3228   // represented as a series of bytes of the constant value.
3229   int Value = isRepeatedByteSequence(CA, DL);
3230 
3231   if (Value != -1) {
3232     uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
3233     AP.OutStreamer->emitFill(Bytes, Value);
3234   } else {
3235     for (unsigned I = 0, E = CA->getNumOperands(); I != E; ++I) {
3236       emitGlobalConstantImpl(DL, CA->getOperand(I), AP, BaseCV, Offset,
3237                              AliasList);
3238       Offset += DL.getTypeAllocSize(CA->getOperand(I)->getType());
3239     }
3240   }
3241 }
3242 
3243 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP);
3244 
3245 static void emitGlobalConstantVector(const DataLayout &DL,
3246                                      const ConstantVector *CV, AsmPrinter &AP,
3247                                      AsmPrinter::AliasMapTy *AliasList) {
3248   Type *ElementType = CV->getType()->getElementType();
3249   uint64_t ElementSizeInBits = DL.getTypeSizeInBits(ElementType);
3250   uint64_t ElementAllocSizeInBits = DL.getTypeAllocSizeInBits(ElementType);
3251   uint64_t EmittedSize;
3252   if (ElementSizeInBits != ElementAllocSizeInBits) {
3253     // If the allocation size of an element is different from the size in bits,
3254     // printing each element separately will insert incorrect padding.
3255     //
3256     // The general algorithm here is complicated; instead of writing it out
3257     // here, just use the existing code in ConstantFolding.
3258     Type *IntT =
3259         IntegerType::get(CV->getContext(), DL.getTypeSizeInBits(CV->getType()));
3260     ConstantInt *CI = dyn_cast_or_null<ConstantInt>(ConstantFoldConstant(
3261         ConstantExpr::getBitCast(const_cast<ConstantVector *>(CV), IntT), DL));
3262     if (!CI) {
3263       report_fatal_error(
3264           "Cannot lower vector global with unusual element type");
3265     }
3266     emitGlobalAliasInline(AP, 0, AliasList);
3267     emitGlobalConstantLargeInt(CI, AP);
3268     EmittedSize = DL.getTypeStoreSize(CV->getType());
3269   } else {
3270     for (unsigned I = 0, E = CV->getType()->getNumElements(); I != E; ++I) {
3271       emitGlobalAliasInline(AP, DL.getTypeAllocSize(CV->getType()) * I, AliasList);
3272       emitGlobalConstantImpl(DL, CV->getOperand(I), AP);
3273     }
3274     EmittedSize =
3275         DL.getTypeAllocSize(ElementType) * CV->getType()->getNumElements();
3276   }
3277 
3278   unsigned Size = DL.getTypeAllocSize(CV->getType());
3279   if (unsigned Padding = Size - EmittedSize)
3280     AP.OutStreamer->emitZeros(Padding);
3281 }
3282 
3283 static void emitGlobalConstantStruct(const DataLayout &DL,
3284                                      const ConstantStruct *CS, AsmPrinter &AP,
3285                                      const Constant *BaseCV, uint64_t Offset,
3286                                      AsmPrinter::AliasMapTy *AliasList) {
3287   // Print the fields in successive locations. Pad to align if needed!
3288   unsigned Size = DL.getTypeAllocSize(CS->getType());
3289   const StructLayout *Layout = DL.getStructLayout(CS->getType());
3290   uint64_t SizeSoFar = 0;
3291   for (unsigned I = 0, E = CS->getNumOperands(); I != E; ++I) {
3292     const Constant *Field = CS->getOperand(I);
3293 
3294     // Print the actual field value.
3295     emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar,
3296                            AliasList);
3297 
3298     // Check if padding is needed and insert one or more 0s.
3299     uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
3300     uint64_t PadSize = ((I == E - 1 ? Size : Layout->getElementOffset(I + 1)) -
3301                         Layout->getElementOffset(I)) -
3302                        FieldSize;
3303     SizeSoFar += FieldSize + PadSize;
3304 
3305     // Insert padding - this may include padding to increase the size of the
3306     // current field up to the ABI size (if the struct is not packed) as well
3307     // as padding to ensure that the next field starts at the right offset.
3308     AP.OutStreamer->emitZeros(PadSize);
3309   }
3310   assert(SizeSoFar == Layout->getSizeInBytes() &&
3311          "Layout of constant struct may be incorrect!");
3312 }
3313 
3314 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP) {
3315   assert(ET && "Unknown float type");
3316   APInt API = APF.bitcastToAPInt();
3317 
3318   // First print a comment with what we think the original floating-point value
3319   // should have been.
3320   if (AP.isVerbose()) {
3321     SmallString<8> StrVal;
3322     APF.toString(StrVal);
3323     ET->print(AP.OutStreamer->getCommentOS());
3324     AP.OutStreamer->getCommentOS() << ' ' << StrVal << '\n';
3325   }
3326 
3327   // Now iterate through the APInt chunks, emitting them in endian-correct
3328   // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
3329   // floats).
3330   unsigned NumBytes = API.getBitWidth() / 8;
3331   unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
3332   const uint64_t *p = API.getRawData();
3333 
3334   // PPC's long double has odd notions of endianness compared to how LLVM
3335   // handles it: p[0] goes first for *big* endian on PPC.
3336   if (AP.getDataLayout().isBigEndian() && !ET->isPPC_FP128Ty()) {
3337     int Chunk = API.getNumWords() - 1;
3338 
3339     if (TrailingBytes)
3340       AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk--], TrailingBytes);
3341 
3342     for (; Chunk >= 0; --Chunk)
3343       AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], sizeof(uint64_t));
3344   } else {
3345     unsigned Chunk;
3346     for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
3347       AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], sizeof(uint64_t));
3348 
3349     if (TrailingBytes)
3350       AP.OutStreamer->emitIntValueInHexWithPadding(p[Chunk], TrailingBytes);
3351   }
3352 
3353   // Emit the tail padding for the long double.
3354   const DataLayout &DL = AP.getDataLayout();
3355   AP.OutStreamer->emitZeros(DL.getTypeAllocSize(ET) - DL.getTypeStoreSize(ET));
3356 }
3357 
3358 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
3359   emitGlobalConstantFP(CFP->getValueAPF(), CFP->getType(), AP);
3360 }
3361 
3362 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
3363   const DataLayout &DL = AP.getDataLayout();
3364   unsigned BitWidth = CI->getBitWidth();
3365 
3366   // Copy the value as we may massage the layout for constants whose bit width
3367   // is not a multiple of 64-bits.
3368   APInt Realigned(CI->getValue());
3369   uint64_t ExtraBits = 0;
3370   unsigned ExtraBitsSize = BitWidth & 63;
3371 
3372   if (ExtraBitsSize) {
3373     // The bit width of the data is not a multiple of 64-bits.
3374     // The extra bits are expected to be at the end of the chunk of the memory.
3375     // Little endian:
3376     // * Nothing to be done, just record the extra bits to emit.
3377     // Big endian:
3378     // * Record the extra bits to emit.
3379     // * Realign the raw data to emit the chunks of 64-bits.
3380     if (DL.isBigEndian()) {
3381       // Basically the structure of the raw data is a chunk of 64-bits cells:
3382       //    0        1         BitWidth / 64
3383       // [chunk1][chunk2] ... [chunkN].
3384       // The most significant chunk is chunkN and it should be emitted first.
3385       // However, due to the alignment issue chunkN contains useless bits.
3386       // Realign the chunks so that they contain only useful information:
3387       // ExtraBits     0       1       (BitWidth / 64) - 1
3388       //       chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
3389       ExtraBitsSize = alignTo(ExtraBitsSize, 8);
3390       ExtraBits = Realigned.getRawData()[0] &
3391         (((uint64_t)-1) >> (64 - ExtraBitsSize));
3392       if (BitWidth >= 64)
3393         Realigned.lshrInPlace(ExtraBitsSize);
3394     } else
3395       ExtraBits = Realigned.getRawData()[BitWidth / 64];
3396   }
3397 
3398   // We don't expect assemblers to support integer data directives
3399   // for more than 64 bits, so we emit the data in at most 64-bit
3400   // quantities at a time.
3401   const uint64_t *RawData = Realigned.getRawData();
3402   for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
3403     uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
3404     AP.OutStreamer->emitIntValue(Val, 8);
3405   }
3406 
3407   if (ExtraBitsSize) {
3408     // Emit the extra bits after the 64-bits chunks.
3409 
3410     // Emit a directive that fills the expected size.
3411     uint64_t Size = AP.getDataLayout().getTypeStoreSize(CI->getType());
3412     Size -= (BitWidth / 64) * 8;
3413     assert(Size && Size * 8 >= ExtraBitsSize &&
3414            (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
3415            == ExtraBits && "Directive too small for extra bits.");
3416     AP.OutStreamer->emitIntValue(ExtraBits, Size);
3417   }
3418 }
3419 
3420 /// Transform a not absolute MCExpr containing a reference to a GOT
3421 /// equivalent global, by a target specific GOT pc relative access to the
3422 /// final symbol.
3423 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
3424                                          const Constant *BaseCst,
3425                                          uint64_t Offset) {
3426   // The global @foo below illustrates a global that uses a got equivalent.
3427   //
3428   //  @bar = global i32 42
3429   //  @gotequiv = private unnamed_addr constant i32* @bar
3430   //  @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
3431   //                             i64 ptrtoint (i32* @foo to i64))
3432   //                        to i32)
3433   //
3434   // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
3435   // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
3436   // form:
3437   //
3438   //  foo = cstexpr, where
3439   //    cstexpr := <gotequiv> - "." + <cst>
3440   //    cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
3441   //
3442   // After canonicalization by evaluateAsRelocatable `ME` turns into:
3443   //
3444   //  cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
3445   //    gotpcrelcst := <offset from @foo base> + <cst>
3446   MCValue MV;
3447   if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
3448     return;
3449   const MCSymbolRefExpr *SymA = MV.getSymA();
3450   if (!SymA)
3451     return;
3452 
3453   // Check that GOT equivalent symbol is cached.
3454   const MCSymbol *GOTEquivSym = &SymA->getSymbol();
3455   if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
3456     return;
3457 
3458   const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
3459   if (!BaseGV)
3460     return;
3461 
3462   // Check for a valid base symbol
3463   const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
3464   const MCSymbolRefExpr *SymB = MV.getSymB();
3465 
3466   if (!SymB || BaseSym != &SymB->getSymbol())
3467     return;
3468 
3469   // Make sure to match:
3470   //
3471   //    gotpcrelcst := <offset from @foo base> + <cst>
3472   //
3473   // If gotpcrelcst is positive it means that we can safely fold the pc rel
3474   // displacement into the GOTPCREL. We can also can have an extra offset <cst>
3475   // if the target knows how to encode it.
3476   int64_t GOTPCRelCst = Offset + MV.getConstant();
3477   if (GOTPCRelCst < 0)
3478     return;
3479   if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
3480     return;
3481 
3482   // Emit the GOT PC relative to replace the got equivalent global, i.e.:
3483   //
3484   //  bar:
3485   //    .long 42
3486   //  gotequiv:
3487   //    .quad bar
3488   //  foo:
3489   //    .long gotequiv - "." + <cst>
3490   //
3491   // is replaced by the target specific equivalent to:
3492   //
3493   //  bar:
3494   //    .long 42
3495   //  foo:
3496   //    .long bar@GOTPCREL+<gotpcrelcst>
3497   AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
3498   const GlobalVariable *GV = Result.first;
3499   int NumUses = (int)Result.second;
3500   const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
3501   const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
3502   *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
3503       FinalGV, FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
3504 
3505   // Update GOT equivalent usage information
3506   --NumUses;
3507   if (NumUses >= 0)
3508     AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
3509 }
3510 
3511 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
3512                                    AsmPrinter &AP, const Constant *BaseCV,
3513                                    uint64_t Offset,
3514                                    AsmPrinter::AliasMapTy *AliasList) {
3515   emitGlobalAliasInline(AP, Offset, AliasList);
3516   uint64_t Size = DL.getTypeAllocSize(CV->getType());
3517 
3518   // Globals with sub-elements such as combinations of arrays and structs
3519   // are handled recursively by emitGlobalConstantImpl. Keep track of the
3520   // constant symbol base and the current position with BaseCV and Offset.
3521   if (!BaseCV && CV->hasOneUse())
3522     BaseCV = dyn_cast<Constant>(CV->user_back());
3523 
3524   if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
3525     return AP.OutStreamer->emitZeros(Size);
3526 
3527   if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
3528     const uint64_t StoreSize = DL.getTypeStoreSize(CV->getType());
3529 
3530     if (StoreSize <= 8) {
3531       if (AP.isVerbose())
3532         AP.OutStreamer->getCommentOS()
3533             << format("0x%" PRIx64 "\n", CI->getZExtValue());
3534       AP.OutStreamer->emitIntValue(CI->getZExtValue(), StoreSize);
3535     } else {
3536       emitGlobalConstantLargeInt(CI, AP);
3537     }
3538 
3539     // Emit tail padding if needed
3540     if (Size != StoreSize)
3541       AP.OutStreamer->emitZeros(Size - StoreSize);
3542 
3543     return;
3544   }
3545 
3546   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
3547     return emitGlobalConstantFP(CFP, AP);
3548 
3549   if (isa<ConstantPointerNull>(CV)) {
3550     AP.OutStreamer->emitIntValue(0, Size);
3551     return;
3552   }
3553 
3554   if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
3555     return emitGlobalConstantDataSequential(DL, CDS, AP, AliasList);
3556 
3557   if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
3558     return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset, AliasList);
3559 
3560   if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
3561     return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset, AliasList);
3562 
3563   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
3564     // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
3565     // vectors).
3566     if (CE->getOpcode() == Instruction::BitCast)
3567       return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
3568 
3569     if (Size > 8) {
3570       // If the constant expression's size is greater than 64-bits, then we have
3571       // to emit the value in chunks. Try to constant fold the value and emit it
3572       // that way.
3573       Constant *New = ConstantFoldConstant(CE, DL);
3574       if (New != CE)
3575         return emitGlobalConstantImpl(DL, New, AP);
3576     }
3577   }
3578 
3579   if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
3580     return emitGlobalConstantVector(DL, V, AP, AliasList);
3581 
3582   // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
3583   // thread the streamer with EmitValue.
3584   const MCExpr *ME = AP.lowerConstant(CV);
3585 
3586   // Since lowerConstant already folded and got rid of all IR pointer and
3587   // integer casts, detect GOT equivalent accesses by looking into the MCExpr
3588   // directly.
3589   if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
3590     handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
3591 
3592   AP.OutStreamer->emitValue(ME, Size);
3593 }
3594 
3595 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
3596 void AsmPrinter::emitGlobalConstant(const DataLayout &DL, const Constant *CV,
3597                                     AliasMapTy *AliasList) {
3598   uint64_t Size = DL.getTypeAllocSize(CV->getType());
3599   if (Size)
3600     emitGlobalConstantImpl(DL, CV, *this, nullptr, 0, AliasList);
3601   else if (MAI->hasSubsectionsViaSymbols()) {
3602     // If the global has zero size, emit a single byte so that two labels don't
3603     // look like they are at the same location.
3604     OutStreamer->emitIntValue(0, 1);
3605   }
3606   if (!AliasList)
3607     return;
3608   // TODO: These remaining aliases are not emitted in the correct location. Need
3609   // to handle the case where the alias offset doesn't refer to any sub-element.
3610   for (auto &AliasPair : *AliasList) {
3611     for (const GlobalAlias *GA : AliasPair.second)
3612       OutStreamer->emitLabel(getSymbol(GA));
3613   }
3614 }
3615 
3616 void AsmPrinter::emitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
3617   // Target doesn't support this yet!
3618   llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
3619 }
3620 
3621 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
3622   if (Offset > 0)
3623     OS << '+' << Offset;
3624   else if (Offset < 0)
3625     OS << Offset;
3626 }
3627 
3628 void AsmPrinter::emitNops(unsigned N) {
3629   MCInst Nop = MF->getSubtarget().getInstrInfo()->getNop();
3630   for (; N; --N)
3631     EmitToStreamer(*OutStreamer, Nop);
3632 }
3633 
3634 //===----------------------------------------------------------------------===//
3635 // Symbol Lowering Routines.
3636 //===----------------------------------------------------------------------===//
3637 
3638 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
3639   return OutContext.createTempSymbol(Name, true);
3640 }
3641 
3642 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
3643   return const_cast<AsmPrinter *>(this)->getAddrLabelSymbol(
3644       BA->getBasicBlock());
3645 }
3646 
3647 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
3648   return const_cast<AsmPrinter *>(this)->getAddrLabelSymbol(BB);
3649 }
3650 
3651 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
3652 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
3653   if (getSubtargetInfo().getTargetTriple().isWindowsMSVCEnvironment()) {
3654     const MachineConstantPoolEntry &CPE =
3655         MF->getConstantPool()->getConstants()[CPID];
3656     if (!CPE.isMachineConstantPoolEntry()) {
3657       const DataLayout &DL = MF->getDataLayout();
3658       SectionKind Kind = CPE.getSectionKind(&DL);
3659       const Constant *C = CPE.Val.ConstVal;
3660       Align Alignment = CPE.Alignment;
3661       if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
3662               getObjFileLowering().getSectionForConstant(DL, Kind, C,
3663                                                          Alignment))) {
3664         if (MCSymbol *Sym = S->getCOMDATSymbol()) {
3665           if (Sym->isUndefined())
3666             OutStreamer->emitSymbolAttribute(Sym, MCSA_Global);
3667           return Sym;
3668         }
3669       }
3670     }
3671   }
3672 
3673   const DataLayout &DL = getDataLayout();
3674   return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
3675                                       "CPI" + Twine(getFunctionNumber()) + "_" +
3676                                       Twine(CPID));
3677 }
3678 
3679 /// GetJTISymbol - Return the symbol for the specified jump table entry.
3680 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
3681   return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
3682 }
3683 
3684 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
3685 /// FIXME: privatize to AsmPrinter.
3686 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
3687   const DataLayout &DL = getDataLayout();
3688   return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
3689                                       Twine(getFunctionNumber()) + "_" +
3690                                       Twine(UID) + "_set_" + Twine(MBBID));
3691 }
3692 
3693 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
3694                                                    StringRef Suffix) const {
3695   return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM);
3696 }
3697 
3698 /// Return the MCSymbol for the specified ExternalSymbol.
3699 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
3700   SmallString<60> NameStr;
3701   Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
3702   return OutContext.getOrCreateSymbol(NameStr);
3703 }
3704 
3705 /// PrintParentLoopComment - Print comments about parent loops of this one.
3706 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
3707                                    unsigned FunctionNumber) {
3708   if (!Loop) return;
3709   PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
3710   OS.indent(Loop->getLoopDepth()*2)
3711     << "Parent Loop BB" << FunctionNumber << "_"
3712     << Loop->getHeader()->getNumber()
3713     << " Depth=" << Loop->getLoopDepth() << '\n';
3714 }
3715 
3716 /// PrintChildLoopComment - Print comments about child loops within
3717 /// the loop for this basic block, with nesting.
3718 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
3719                                   unsigned FunctionNumber) {
3720   // Add child loop information
3721   for (const MachineLoop *CL : *Loop) {
3722     OS.indent(CL->getLoopDepth()*2)
3723       << "Child Loop BB" << FunctionNumber << "_"
3724       << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
3725       << '\n';
3726     PrintChildLoopComment(OS, CL, FunctionNumber);
3727   }
3728 }
3729 
3730 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
3731 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
3732                                        const MachineLoopInfo *LI,
3733                                        const AsmPrinter &AP) {
3734   // Add loop depth information
3735   const MachineLoop *Loop = LI->getLoopFor(&MBB);
3736   if (!Loop) return;
3737 
3738   MachineBasicBlock *Header = Loop->getHeader();
3739   assert(Header && "No header for loop");
3740 
3741   // If this block is not a loop header, just print out what is the loop header
3742   // and return.
3743   if (Header != &MBB) {
3744     AP.OutStreamer->AddComment("  in Loop: Header=BB" +
3745                                Twine(AP.getFunctionNumber())+"_" +
3746                                Twine(Loop->getHeader()->getNumber())+
3747                                " Depth="+Twine(Loop->getLoopDepth()));
3748     return;
3749   }
3750 
3751   // Otherwise, it is a loop header.  Print out information about child and
3752   // parent loops.
3753   raw_ostream &OS = AP.OutStreamer->getCommentOS();
3754 
3755   PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
3756 
3757   OS << "=>";
3758   OS.indent(Loop->getLoopDepth()*2-2);
3759 
3760   OS << "This ";
3761   if (Loop->isInnermost())
3762     OS << "Inner ";
3763   OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
3764 
3765   PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
3766 }
3767 
3768 /// emitBasicBlockStart - This method prints the label for the specified
3769 /// MachineBasicBlock, an alignment (if present) and a comment describing
3770 /// it if appropriate.
3771 void AsmPrinter::emitBasicBlockStart(const MachineBasicBlock &MBB) {
3772   // End the previous funclet and start a new one.
3773   if (MBB.isEHFuncletEntry()) {
3774     for (const HandlerInfo &HI : Handlers) {
3775       HI.Handler->endFunclet();
3776       HI.Handler->beginFunclet(MBB);
3777     }
3778   }
3779 
3780   // Switch to a new section if this basic block must begin a section. The
3781   // entry block is always placed in the function section and is handled
3782   // separately.
3783   if (MBB.isBeginSection() && !MBB.isEntryBlock()) {
3784     OutStreamer->switchSection(
3785         getObjFileLowering().getSectionForMachineBasicBlock(MF->getFunction(),
3786                                                             MBB, TM));
3787     CurrentSectionBeginSym = MBB.getSymbol();
3788   }
3789 
3790   // Emit an alignment directive for this block, if needed.
3791   const Align Alignment = MBB.getAlignment();
3792   if (Alignment != Align(1))
3793     emitAlignment(Alignment, nullptr, MBB.getMaxBytesForAlignment());
3794 
3795   // If the block has its address taken, emit any labels that were used to
3796   // reference the block.  It is possible that there is more than one label
3797   // here, because multiple LLVM BB's may have been RAUW'd to this block after
3798   // the references were generated.
3799   if (MBB.isIRBlockAddressTaken()) {
3800     if (isVerbose())
3801       OutStreamer->AddComment("Block address taken");
3802 
3803     BasicBlock *BB = MBB.getAddressTakenIRBlock();
3804     assert(BB && BB->hasAddressTaken() && "Missing BB");
3805     for (MCSymbol *Sym : getAddrLabelSymbolToEmit(BB))
3806       OutStreamer->emitLabel(Sym);
3807   } else if (isVerbose() && MBB.isMachineBlockAddressTaken()) {
3808     OutStreamer->AddComment("Block address taken");
3809   }
3810 
3811   // Print some verbose block comments.
3812   if (isVerbose()) {
3813     if (const BasicBlock *BB = MBB.getBasicBlock()) {
3814       if (BB->hasName()) {
3815         BB->printAsOperand(OutStreamer->getCommentOS(),
3816                            /*PrintType=*/false, BB->getModule());
3817         OutStreamer->getCommentOS() << '\n';
3818       }
3819     }
3820 
3821     assert(MLI != nullptr && "MachineLoopInfo should has been computed");
3822     emitBasicBlockLoopComments(MBB, MLI, *this);
3823   }
3824 
3825   // Print the main label for the block.
3826   if (shouldEmitLabelForBasicBlock(MBB)) {
3827     if (isVerbose() && MBB.hasLabelMustBeEmitted())
3828       OutStreamer->AddComment("Label of block must be emitted");
3829     OutStreamer->emitLabel(MBB.getSymbol());
3830   } else {
3831     if (isVerbose()) {
3832       // NOTE: Want this comment at start of line, don't emit with AddComment.
3833       OutStreamer->emitRawComment(" %bb." + Twine(MBB.getNumber()) + ":",
3834                                   false);
3835     }
3836   }
3837 
3838   if (MBB.isEHCatchretTarget() &&
3839       MAI->getExceptionHandlingType() == ExceptionHandling::WinEH) {
3840     OutStreamer->emitLabel(MBB.getEHCatchretSymbol());
3841   }
3842 
3843   // With BB sections, each basic block must handle CFI information on its own
3844   // if it begins a section (Entry block call is handled separately, next to
3845   // beginFunction).
3846   if (MBB.isBeginSection() && !MBB.isEntryBlock())
3847     for (const HandlerInfo &HI : Handlers)
3848       HI.Handler->beginBasicBlockSection(MBB);
3849 }
3850 
3851 void AsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) {
3852   // Check if CFI information needs to be updated for this MBB with basic block
3853   // sections.
3854   if (MBB.isEndSection())
3855     for (const HandlerInfo &HI : Handlers)
3856       HI.Handler->endBasicBlockSection(MBB);
3857 }
3858 
3859 void AsmPrinter::emitVisibility(MCSymbol *Sym, unsigned Visibility,
3860                                 bool IsDefinition) const {
3861   MCSymbolAttr Attr = MCSA_Invalid;
3862 
3863   switch (Visibility) {
3864   default: break;
3865   case GlobalValue::HiddenVisibility:
3866     if (IsDefinition)
3867       Attr = MAI->getHiddenVisibilityAttr();
3868     else
3869       Attr = MAI->getHiddenDeclarationVisibilityAttr();
3870     break;
3871   case GlobalValue::ProtectedVisibility:
3872     Attr = MAI->getProtectedVisibilityAttr();
3873     break;
3874   }
3875 
3876   if (Attr != MCSA_Invalid)
3877     OutStreamer->emitSymbolAttribute(Sym, Attr);
3878 }
3879 
3880 bool AsmPrinter::shouldEmitLabelForBasicBlock(
3881     const MachineBasicBlock &MBB) const {
3882   // With `-fbasic-block-sections=`, a label is needed for every non-entry block
3883   // in the labels mode (option `=labels`) and every section beginning in the
3884   // sections mode (`=all` and `=list=`).
3885   if ((MF->hasBBLabels() || MBB.isBeginSection()) && !MBB.isEntryBlock())
3886     return true;
3887   // A label is needed for any block with at least one predecessor (when that
3888   // predecessor is not the fallthrough predecessor, or if it is an EH funclet
3889   // entry, or if a label is forced).
3890   return !MBB.pred_empty() &&
3891          (!isBlockOnlyReachableByFallthrough(&MBB) || MBB.isEHFuncletEntry() ||
3892           MBB.hasLabelMustBeEmitted());
3893 }
3894 
3895 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
3896 /// exactly one predecessor and the control transfer mechanism between
3897 /// the predecessor and this block is a fall-through.
3898 bool AsmPrinter::
3899 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
3900   // If this is a landing pad, it isn't a fall through.  If it has no preds,
3901   // then nothing falls through to it.
3902   if (MBB->isEHPad() || MBB->pred_empty())
3903     return false;
3904 
3905   // If there isn't exactly one predecessor, it can't be a fall through.
3906   if (MBB->pred_size() > 1)
3907     return false;
3908 
3909   // The predecessor has to be immediately before this block.
3910   MachineBasicBlock *Pred = *MBB->pred_begin();
3911   if (!Pred->isLayoutSuccessor(MBB))
3912     return false;
3913 
3914   // If the block is completely empty, then it definitely does fall through.
3915   if (Pred->empty())
3916     return true;
3917 
3918   // Check the terminators in the previous blocks
3919   for (const auto &MI : Pred->terminators()) {
3920     // If it is not a simple branch, we are in a table somewhere.
3921     if (!MI.isBranch() || MI.isIndirectBranch())
3922       return false;
3923 
3924     // If we are the operands of one of the branches, this is not a fall
3925     // through. Note that targets with delay slots will usually bundle
3926     // terminators with the delay slot instruction.
3927     for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
3928       if (OP->isJTI())
3929         return false;
3930       if (OP->isMBB() && OP->getMBB() == MBB)
3931         return false;
3932     }
3933   }
3934 
3935   return true;
3936 }
3937 
3938 GCMetadataPrinter *AsmPrinter::getOrCreateGCPrinter(GCStrategy &S) {
3939   if (!S.usesMetadata())
3940     return nullptr;
3941 
3942   auto [GCPI, Inserted] = GCMetadataPrinters.insert({&S, nullptr});
3943   if (!Inserted)
3944     return GCPI->second.get();
3945 
3946   auto Name = S.getName();
3947 
3948   for (const GCMetadataPrinterRegistry::entry &GCMetaPrinter :
3949        GCMetadataPrinterRegistry::entries())
3950     if (Name == GCMetaPrinter.getName()) {
3951       std::unique_ptr<GCMetadataPrinter> GMP = GCMetaPrinter.instantiate();
3952       GMP->S = &S;
3953       GCPI->second = std::move(GMP);
3954       return GCPI->second.get();
3955     }
3956 
3957   report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
3958 }
3959 
3960 void AsmPrinter::emitStackMaps() {
3961   GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
3962   assert(MI && "AsmPrinter didn't require GCModuleInfo?");
3963   bool NeedsDefault = false;
3964   if (MI->begin() == MI->end())
3965     // No GC strategy, use the default format.
3966     NeedsDefault = true;
3967   else
3968     for (const auto &I : *MI) {
3969       if (GCMetadataPrinter *MP = getOrCreateGCPrinter(*I))
3970         if (MP->emitStackMaps(SM, *this))
3971           continue;
3972       // The strategy doesn't have printer or doesn't emit custom stack maps.
3973       // Use the default format.
3974       NeedsDefault = true;
3975     }
3976 
3977   if (NeedsDefault)
3978     SM.serializeToStackMapSection();
3979 }
3980 
3981 /// Pin vtable to this file.
3982 AsmPrinterHandler::~AsmPrinterHandler() = default;
3983 
3984 void AsmPrinterHandler::markFunctionEnd() {}
3985 
3986 // In the binary's "xray_instr_map" section, an array of these function entries
3987 // describes each instrumentation point.  When XRay patches your code, the index
3988 // into this table will be given to your handler as a patch point identifier.
3989 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out) const {
3990   auto Kind8 = static_cast<uint8_t>(Kind);
3991   Out->emitBinaryData(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
3992   Out->emitBinaryData(
3993       StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
3994   Out->emitBinaryData(StringRef(reinterpret_cast<const char *>(&Version), 1));
3995   auto Padding = (4 * Bytes) - ((2 * Bytes) + 3);
3996   assert(Padding >= 0 && "Instrumentation map entry > 4 * Word Size");
3997   Out->emitZeros(Padding);
3998 }
3999 
4000 void AsmPrinter::emitXRayTable() {
4001   if (Sleds.empty())
4002     return;
4003 
4004   auto PrevSection = OutStreamer->getCurrentSectionOnly();
4005   const Function &F = MF->getFunction();
4006   MCSection *InstMap = nullptr;
4007   MCSection *FnSledIndex = nullptr;
4008   const Triple &TT = TM.getTargetTriple();
4009   // Use PC-relative addresses on all targets.
4010   if (TT.isOSBinFormatELF()) {
4011     auto LinkedToSym = cast<MCSymbolELF>(CurrentFnSym);
4012     auto Flags = ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER;
4013     StringRef GroupName;
4014     if (F.hasComdat()) {
4015       Flags |= ELF::SHF_GROUP;
4016       GroupName = F.getComdat()->getName();
4017     }
4018     InstMap = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
4019                                        Flags, 0, GroupName, F.hasComdat(),
4020                                        MCSection::NonUniqueID, LinkedToSym);
4021 
4022     if (TM.Options.XRayFunctionIndex)
4023       FnSledIndex = OutContext.getELFSection(
4024           "xray_fn_idx", ELF::SHT_PROGBITS, Flags, 0, GroupName, F.hasComdat(),
4025           MCSection::NonUniqueID, LinkedToSym);
4026   } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
4027     InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map",
4028                                          MachO::S_ATTR_LIVE_SUPPORT,
4029                                          SectionKind::getReadOnlyWithRel());
4030     if (TM.Options.XRayFunctionIndex)
4031       FnSledIndex = OutContext.getMachOSection("__DATA", "xray_fn_idx",
4032                                                MachO::S_ATTR_LIVE_SUPPORT,
4033                                                SectionKind::getReadOnly());
4034   } else {
4035     llvm_unreachable("Unsupported target");
4036   }
4037 
4038   auto WordSizeBytes = MAI->getCodePointerSize();
4039 
4040   // Now we switch to the instrumentation map section. Because this is done
4041   // per-function, we are able to create an index entry that will represent the
4042   // range of sleds associated with a function.
4043   auto &Ctx = OutContext;
4044   MCSymbol *SledsStart =
4045       OutContext.createLinkerPrivateSymbol("xray_sleds_start");
4046   OutStreamer->switchSection(InstMap);
4047   OutStreamer->emitLabel(SledsStart);
4048   for (const auto &Sled : Sleds) {
4049     MCSymbol *Dot = Ctx.createTempSymbol();
4050     OutStreamer->emitLabel(Dot);
4051     OutStreamer->emitValueImpl(
4052         MCBinaryExpr::createSub(MCSymbolRefExpr::create(Sled.Sled, Ctx),
4053                                 MCSymbolRefExpr::create(Dot, Ctx), Ctx),
4054         WordSizeBytes);
4055     OutStreamer->emitValueImpl(
4056         MCBinaryExpr::createSub(
4057             MCSymbolRefExpr::create(CurrentFnBegin, Ctx),
4058             MCBinaryExpr::createAdd(MCSymbolRefExpr::create(Dot, Ctx),
4059                                     MCConstantExpr::create(WordSizeBytes, Ctx),
4060                                     Ctx),
4061             Ctx),
4062         WordSizeBytes);
4063     Sled.emit(WordSizeBytes, OutStreamer.get());
4064   }
4065   MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_sleds_end", true);
4066   OutStreamer->emitLabel(SledsEnd);
4067 
4068   // We then emit a single entry in the index per function. We use the symbols
4069   // that bound the instrumentation map as the range for a specific function.
4070   // Each entry here will be 2 * word size aligned, as we're writing down two
4071   // pointers. This should work for both 32-bit and 64-bit platforms.
4072   if (FnSledIndex) {
4073     OutStreamer->switchSection(FnSledIndex);
4074     OutStreamer->emitCodeAlignment(Align(2 * WordSizeBytes),
4075                                    &getSubtargetInfo());
4076     // For Mach-O, use an "l" symbol as the atom of this subsection. The label
4077     // difference uses a SUBTRACTOR external relocation which references the
4078     // symbol.
4079     MCSymbol *Dot = Ctx.createLinkerPrivateSymbol("xray_fn_idx");
4080     OutStreamer->emitLabel(Dot);
4081     OutStreamer->emitValueImpl(
4082         MCBinaryExpr::createSub(MCSymbolRefExpr::create(SledsStart, Ctx),
4083                                 MCSymbolRefExpr::create(Dot, Ctx), Ctx),
4084         WordSizeBytes);
4085     OutStreamer->emitValueImpl(MCConstantExpr::create(Sleds.size(), Ctx),
4086                                WordSizeBytes);
4087     OutStreamer->switchSection(PrevSection);
4088   }
4089   Sleds.clear();
4090 }
4091 
4092 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
4093                             SledKind Kind, uint8_t Version) {
4094   const Function &F = MI.getMF()->getFunction();
4095   auto Attr = F.getFnAttribute("function-instrument");
4096   bool LogArgs = F.hasFnAttribute("xray-log-args");
4097   bool AlwaysInstrument =
4098     Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always";
4099   if (Kind == SledKind::FUNCTION_ENTER && LogArgs)
4100     Kind = SledKind::LOG_ARGS_ENTER;
4101   Sleds.emplace_back(XRayFunctionEntry{Sled, CurrentFnSym, Kind,
4102                                        AlwaysInstrument, &F, Version});
4103 }
4104 
4105 void AsmPrinter::emitPatchableFunctionEntries() {
4106   const Function &F = MF->getFunction();
4107   unsigned PatchableFunctionPrefix = 0, PatchableFunctionEntry = 0;
4108   (void)F.getFnAttribute("patchable-function-prefix")
4109       .getValueAsString()
4110       .getAsInteger(10, PatchableFunctionPrefix);
4111   (void)F.getFnAttribute("patchable-function-entry")
4112       .getValueAsString()
4113       .getAsInteger(10, PatchableFunctionEntry);
4114   if (!PatchableFunctionPrefix && !PatchableFunctionEntry)
4115     return;
4116   const unsigned PointerSize = getPointerSize();
4117   if (TM.getTargetTriple().isOSBinFormatELF()) {
4118     auto Flags = ELF::SHF_WRITE | ELF::SHF_ALLOC;
4119     const MCSymbolELF *LinkedToSym = nullptr;
4120     StringRef GroupName;
4121 
4122     // GNU as < 2.35 did not support section flag 'o'. GNU ld < 2.36 did not
4123     // support mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER sections.
4124     if (MAI->useIntegratedAssembler() || MAI->binutilsIsAtLeast(2, 36)) {
4125       Flags |= ELF::SHF_LINK_ORDER;
4126       if (F.hasComdat()) {
4127         Flags |= ELF::SHF_GROUP;
4128         GroupName = F.getComdat()->getName();
4129       }
4130       LinkedToSym = cast<MCSymbolELF>(CurrentFnSym);
4131     }
4132     OutStreamer->switchSection(OutContext.getELFSection(
4133         "__patchable_function_entries", ELF::SHT_PROGBITS, Flags, 0, GroupName,
4134         F.hasComdat(), MCSection::NonUniqueID, LinkedToSym));
4135     emitAlignment(Align(PointerSize));
4136     OutStreamer->emitSymbolValue(CurrentPatchableFunctionEntrySym, PointerSize);
4137   }
4138 }
4139 
4140 uint16_t AsmPrinter::getDwarfVersion() const {
4141   return OutStreamer->getContext().getDwarfVersion();
4142 }
4143 
4144 void AsmPrinter::setDwarfVersion(uint16_t Version) {
4145   OutStreamer->getContext().setDwarfVersion(Version);
4146 }
4147 
4148 bool AsmPrinter::isDwarf64() const {
4149   return OutStreamer->getContext().getDwarfFormat() == dwarf::DWARF64;
4150 }
4151 
4152 unsigned int AsmPrinter::getDwarfOffsetByteSize() const {
4153   return dwarf::getDwarfOffsetByteSize(
4154       OutStreamer->getContext().getDwarfFormat());
4155 }
4156 
4157 dwarf::FormParams AsmPrinter::getDwarfFormParams() const {
4158   return {getDwarfVersion(), uint8_t(MAI->getCodePointerSize()),
4159           OutStreamer->getContext().getDwarfFormat(),
4160           doesDwarfUseRelocationsAcrossSections()};
4161 }
4162 
4163 unsigned int AsmPrinter::getUnitLengthFieldByteSize() const {
4164   return dwarf::getUnitLengthFieldByteSize(
4165       OutStreamer->getContext().getDwarfFormat());
4166 }
4167