1 //===- AsmPrinter.cpp - Common AsmPrinter code ----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the AsmPrinter class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/AsmPrinter.h"
15 #include "CodeViewDebug.h"
16 #include "DwarfDebug.h"
17 #include "DwarfException.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/StringRef.h"
30 #include "llvm/ADT/Triple.h"
31 #include "llvm/ADT/Twine.h"
32 #include "llvm/Analysis/ConstantFolding.h"
33 #include "llvm/Analysis/EHPersonalities.h"
34 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
35 #include "llvm/BinaryFormat/COFF.h"
36 #include "llvm/BinaryFormat/Dwarf.h"
37 #include "llvm/BinaryFormat/ELF.h"
38 #include "llvm/CodeGen/AsmPrinterHandler.h"
39 #include "llvm/CodeGen/GCMetadata.h"
40 #include "llvm/CodeGen/GCMetadataPrinter.h"
41 #include "llvm/CodeGen/GCStrategy.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/MachineMemOperand.h"
53 #include "llvm/CodeGen/MachineModuleInfo.h"
54 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
55 #include "llvm/CodeGen/MachineOperand.h"
56 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
57 #include "llvm/CodeGen/StackMaps.h"
58 #include "llvm/CodeGen/TargetFrameLowering.h"
59 #include "llvm/CodeGen/TargetInstrInfo.h"
60 #include "llvm/CodeGen/TargetLowering.h"
61 #include "llvm/CodeGen/TargetOpcodes.h"
62 #include "llvm/CodeGen/TargetRegisterInfo.h"
63 #include "llvm/CodeGen/TargetSubtargetInfo.h"
64 #include "llvm/IR/BasicBlock.h"
65 #include "llvm/IR/Comdat.h"
66 #include "llvm/IR/Constant.h"
67 #include "llvm/IR/Constants.h"
68 #include "llvm/IR/DataLayout.h"
69 #include "llvm/IR/DebugInfoMetadata.h"
70 #include "llvm/IR/DerivedTypes.h"
71 #include "llvm/IR/Function.h"
72 #include "llvm/IR/GlobalAlias.h"
73 #include "llvm/IR/GlobalIFunc.h"
74 #include "llvm/IR/GlobalIndirectSymbol.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/Type.h"
84 #include "llvm/IR/Value.h"
85 #include "llvm/MC/MCAsmInfo.h"
86 #include "llvm/MC/MCCodePadder.h"
87 #include "llvm/MC/MCContext.h"
88 #include "llvm/MC/MCDirectives.h"
89 #include "llvm/MC/MCDwarf.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/Pass.h"
104 #include "llvm/Support/Casting.h"
105 #include "llvm/Support/CommandLine.h"
106 #include "llvm/Support/Compiler.h"
107 #include "llvm/Support/ErrorHandling.h"
108 #include "llvm/Support/Format.h"
109 #include "llvm/Support/MathExtras.h"
110 #include "llvm/Support/Path.h"
111 #include "llvm/Support/TargetRegistry.h"
112 #include "llvm/Support/Timer.h"
113 #include "llvm/Support/raw_ostream.h"
114 #include "llvm/Target/TargetLoweringObjectFile.h"
115 #include "llvm/Target/TargetMachine.h"
116 #include "llvm/Target/TargetOptions.h"
128 using namespace llvm;
130 #define DEBUG_TYPE "asm-printer"
132 static const char *const DWARFGroupName = "dwarf";
133 static const char *const DWARFGroupDescription = "DWARF Emission";
134 static const char *const DbgTimerName = "emit";
135 static const char *const DbgTimerDescription = "Debug Info Emission";
136 static const char *const EHTimerName = "write_exception";
137 static const char *const EHTimerDescription = "DWARF Exception Writer";
138 static const char *const CFGuardName = "Control Flow Guard";
139 static const char *const CFGuardDescription = "Control Flow Guard Tables";
140 static const char *const CodeViewLineTablesGroupName = "linetables";
141 static const char *const CodeViewLineTablesGroupDescription =
142 "CodeView Line Tables";
144 STATISTIC(EmittedInsts, "Number of machine instrs printed");
147 PrintSchedule("print-schedule", cl::Hidden, cl::init(false),
148 cl::desc("Print 'sched: [latency:throughput]' in .s output"));
150 char AsmPrinter::ID = 0;
152 using gcp_map_type = DenseMap<GCStrategy *, std::unique_ptr<GCMetadataPrinter>>;
154 static gcp_map_type &getGCMap(void *&P) {
156 P = new gcp_map_type();
157 return *(gcp_map_type*)P;
160 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
161 /// value in log2 form. This rounds up to the preferred alignment if possible
163 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
164 unsigned InBits = 0) {
165 unsigned NumBits = 0;
166 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
167 NumBits = DL.getPreferredAlignmentLog(GVar);
169 // If InBits is specified, round it to it.
170 if (InBits > NumBits)
173 // If the GV has a specified alignment, take it into account.
174 if (GV->getAlignment() == 0)
177 unsigned GVAlign = Log2_32(GV->getAlignment());
179 // If the GVAlign is larger than NumBits, or if we are required to obey
180 // NumBits because the GV has an assigned section, obey it.
181 if (GVAlign > NumBits || GV->hasSection())
186 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
187 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
188 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) {
189 VerboseAsm = OutStreamer->isVerboseAsm();
192 AsmPrinter::~AsmPrinter() {
193 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
195 if (GCMetadataPrinters) {
196 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
199 GCMetadataPrinters = nullptr;
203 bool AsmPrinter::isPositionIndependent() const {
204 return TM.isPositionIndependent();
207 /// getFunctionNumber - Return a unique ID for the current function.
208 unsigned AsmPrinter::getFunctionNumber() const {
209 return MF->getFunctionNumber();
212 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
213 return *TM.getObjFileLowering();
216 const DataLayout &AsmPrinter::getDataLayout() const {
217 return MMI->getModule()->getDataLayout();
220 // Do not use the cached DataLayout because some client use it without a Module
221 // (dsymutil, llvm-dwarfdump).
222 unsigned AsmPrinter::getPointerSize() const {
223 return TM.getPointerSize(0); // FIXME: Default address space
226 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
227 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
228 return MF->getSubtarget<MCSubtargetInfo>();
231 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
232 S.EmitInstruction(Inst, getSubtargetInfo());
235 /// getCurrentSection() - Return the current section we are emitting to.
236 const MCSection *AsmPrinter::getCurrentSection() const {
237 return OutStreamer->getCurrentSectionOnly();
240 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
241 AU.setPreservesAll();
242 MachineFunctionPass::getAnalysisUsage(AU);
243 AU.addRequired<MachineModuleInfo>();
244 AU.addRequired<MachineOptimizationRemarkEmitterPass>();
245 AU.addRequired<GCModuleInfo>();
248 bool AsmPrinter::doInitialization(Module &M) {
249 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
251 // Initialize TargetLoweringObjectFile.
252 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
253 .Initialize(OutContext, TM);
255 OutStreamer->InitSections(false);
257 // Emit the version-min deployment target directive if needed.
259 // FIXME: If we end up with a collection of these sorts of Darwin-specific
260 // or ELF-specific things, it may make sense to have a platform helper class
261 // that will work with the target helper class. For now keep it here, as the
262 // alternative is duplicated code in each of the target asm printers that
263 // use the directive, where it would need the same conditionalization
265 const Triple &Target = TM.getTargetTriple();
266 OutStreamer->EmitVersionForTarget(Target, M.getSDKVersion());
268 // Allow the target to emit any magic that it wants at the start of the file.
269 EmitStartOfAsmFile(M);
271 // Very minimal debug info. It is ignored if we emit actual debug info. If we
272 // don't, this at least helps the user find where a global came from.
273 if (MAI->hasSingleParameterDotFile()) {
275 OutStreamer->EmitFileDirective(
276 llvm::sys::path::filename(M.getSourceFileName()));
279 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
280 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
282 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
283 MP->beginAssembly(M, *MI, *this);
285 // Emit module-level inline asm if it exists.
286 if (!M.getModuleInlineAsm().empty()) {
287 // We're at the module level. Construct MCSubtarget from the default CPU
288 // and target triple.
289 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
290 TM.getTargetTriple().str(), TM.getTargetCPU(),
291 TM.getTargetFeatureString()));
292 OutStreamer->AddComment("Start of file scope inline assembly");
293 OutStreamer->AddBlankLine();
294 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
295 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
296 OutStreamer->AddComment("End of file scope inline assembly");
297 OutStreamer->AddBlankLine();
300 if (MAI->doesSupportDebugInformation()) {
301 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
302 if (EmitCodeView && TM.getTargetTriple().isOSWindows()) {
303 Handlers.push_back(HandlerInfo(new CodeViewDebug(this),
304 DbgTimerName, DbgTimerDescription,
305 CodeViewLineTablesGroupName,
306 CodeViewLineTablesGroupDescription));
308 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
309 DD = new DwarfDebug(this, &M);
311 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DbgTimerDescription,
312 DWARFGroupName, DWARFGroupDescription));
316 switch (MAI->getExceptionHandlingType()) {
317 case ExceptionHandling::SjLj:
318 case ExceptionHandling::DwarfCFI:
319 case ExceptionHandling::ARM:
320 isCFIMoveForDebugging = true;
321 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
323 for (auto &F: M.getFunctionList()) {
324 // If the module contains any function with unwind data,
325 // .eh_frame has to be emitted.
326 // Ignore functions that won't get emitted.
327 if (!F.isDeclarationForLinker() && F.needsUnwindTableEntry()) {
328 isCFIMoveForDebugging = false;
334 isCFIMoveForDebugging = false;
338 EHStreamer *ES = nullptr;
339 switch (MAI->getExceptionHandlingType()) {
340 case ExceptionHandling::None:
342 case ExceptionHandling::SjLj:
343 case ExceptionHandling::DwarfCFI:
344 ES = new DwarfCFIException(this);
346 case ExceptionHandling::ARM:
347 ES = new ARMException(this);
349 case ExceptionHandling::WinEH:
350 switch (MAI->getWinEHEncodingType()) {
351 default: llvm_unreachable("unsupported unwinding information encoding");
352 case WinEH::EncodingType::Invalid:
354 case WinEH::EncodingType::X86:
355 case WinEH::EncodingType::Itanium:
356 ES = new WinException(this);
360 case ExceptionHandling::Wasm:
361 ES = new WasmException(this);
365 Handlers.push_back(HandlerInfo(ES, EHTimerName, EHTimerDescription,
366 DWARFGroupName, DWARFGroupDescription));
368 if (mdconst::extract_or_null<ConstantInt>(
369 MMI->getModule()->getModuleFlag("cfguardtable")))
370 Handlers.push_back(HandlerInfo(new WinCFGuard(this), CFGuardName,
371 CFGuardDescription, DWARFGroupName,
372 DWARFGroupDescription));
377 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
378 if (!MAI.hasWeakDefCanBeHiddenDirective())
381 return GV->canBeOmittedFromSymbolTable();
384 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
385 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
387 case GlobalValue::CommonLinkage:
388 case GlobalValue::LinkOnceAnyLinkage:
389 case GlobalValue::LinkOnceODRLinkage:
390 case GlobalValue::WeakAnyLinkage:
391 case GlobalValue::WeakODRLinkage:
392 if (MAI->hasWeakDefDirective()) {
394 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
396 if (!canBeHidden(GV, *MAI))
397 // .weak_definition _foo
398 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
400 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
401 } else if (MAI->hasLinkOnceDirective()) {
403 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
404 //NOTE: linkonce is handled by the section the symbol was assigned to.
407 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
410 case GlobalValue::ExternalLinkage:
411 // If external, declare as a global symbol: .globl _foo
412 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
414 case GlobalValue::PrivateLinkage:
415 case GlobalValue::InternalLinkage:
417 case GlobalValue::AppendingLinkage:
418 case GlobalValue::AvailableExternallyLinkage:
419 case GlobalValue::ExternalWeakLinkage:
420 llvm_unreachable("Should never emit this");
422 llvm_unreachable("Unknown linkage type!");
425 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
426 const GlobalValue *GV) const {
427 TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
430 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
431 return TM.getSymbol(GV);
434 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
435 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
436 bool IsEmuTLSVar = TM.useEmulatedTLS() && GV->isThreadLocal();
437 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
438 "No emulated TLS variables in the common section");
440 // Never emit TLS variable xyz in emulated TLS model.
441 // The initialization value is in __emutls_t.xyz instead of xyz.
445 if (GV->hasInitializer()) {
446 // Check to see if this is a special global used by LLVM, if so, emit it.
447 if (EmitSpecialLLVMGlobal(GV))
450 // Skip the emission of global equivalents. The symbol can be emitted later
451 // on by emitGlobalGOTEquivs in case it turns out to be needed.
452 if (GlobalGOTEquivs.count(getSymbol(GV)))
456 // When printing the control variable __emutls_v.*,
457 // we don't need to print the original TLS variable name.
458 GV->printAsOperand(OutStreamer->GetCommentOS(),
459 /*PrintType=*/false, GV->getParent());
460 OutStreamer->GetCommentOS() << '\n';
464 MCSymbol *GVSym = getSymbol(GV);
465 MCSymbol *EmittedSym = GVSym;
467 // getOrCreateEmuTLSControlSym only creates the symbol with name and default
469 // GV's or GVSym's attributes will be used for the EmittedSym.
470 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
472 if (!GV->hasInitializer()) // External globals require no extra code.
475 GVSym->redefineIfPossible();
476 if (GVSym->isDefined() || GVSym->isVariable())
477 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
478 "' is already defined");
480 if (MAI->hasDotTypeDotSizeDirective())
481 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
483 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
485 const DataLayout &DL = GV->getParent()->getDataLayout();
486 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
488 // If the alignment is specified, we *must* obey it. Overaligning a global
489 // with a specified alignment is a prompt way to break globals emitted to
490 // sections and expected to be contiguous (e.g. ObjC metadata).
491 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
493 for (const HandlerInfo &HI : Handlers) {
494 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
495 HI.TimerGroupName, HI.TimerGroupDescription,
496 TimePassesIsEnabled);
497 HI.Handler->setSymbolSize(GVSym, Size);
500 // Handle common symbols
501 if (GVKind.isCommon()) {
502 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
503 unsigned Align = 1 << AlignLog;
504 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
508 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
512 // Determine to which section this global should be emitted.
513 MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
515 // If we have a bss global going to a section that supports the
516 // zerofill directive, do so here.
517 if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
518 TheSection->isVirtualSection()) {
520 Size = 1; // zerofill of 0 bytes is undefined.
521 unsigned Align = 1 << AlignLog;
522 EmitLinkage(GV, GVSym);
523 // .zerofill __DATA, __bss, _foo, 400, 5
524 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
528 // If this is a BSS local symbol and we are emitting in the BSS
529 // section use .lcomm/.comm directive.
530 if (GVKind.isBSSLocal() &&
531 getObjFileLowering().getBSSSection() == TheSection) {
533 Size = 1; // .comm Foo, 0 is undefined, avoid it.
534 unsigned Align = 1 << AlignLog;
536 // Use .lcomm only if it supports user-specified alignment.
537 // Otherwise, while it would still be correct to use .lcomm in some
538 // cases (e.g. when Align == 1), the external assembler might enfore
539 // some -unknown- default alignment behavior, which could cause
540 // spurious differences between external and integrated assembler.
541 // Prefer to simply fall back to .local / .comm in this case.
542 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
544 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
548 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
552 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
554 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
558 // Handle thread local data for mach-o which requires us to output an
559 // additional structure of data and mangle the original symbol so that we
560 // can reference it later.
562 // TODO: This should become an "emit thread local global" method on TLOF.
563 // All of this macho specific stuff should be sunk down into TLOFMachO and
564 // stuff like "TLSExtraDataSection" should no longer be part of the parent
565 // TLOF class. This will also make it more obvious that stuff like
566 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
568 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
569 // Emit the .tbss symbol
571 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
573 if (GVKind.isThreadBSS()) {
574 TheSection = getObjFileLowering().getTLSBSSSection();
575 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
576 } else if (GVKind.isThreadData()) {
577 OutStreamer->SwitchSection(TheSection);
579 EmitAlignment(AlignLog, GV);
580 OutStreamer->EmitLabel(MangSym);
582 EmitGlobalConstant(GV->getParent()->getDataLayout(),
583 GV->getInitializer());
586 OutStreamer->AddBlankLine();
588 // Emit the variable struct for the runtime.
589 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
591 OutStreamer->SwitchSection(TLVSect);
592 // Emit the linkage here.
593 EmitLinkage(GV, GVSym);
594 OutStreamer->EmitLabel(GVSym);
596 // Three pointers in size:
597 // - __tlv_bootstrap - used to make sure support exists
598 // - spare pointer, used when mapped by the runtime
599 // - pointer to mangled symbol above with initializer
600 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
601 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
603 OutStreamer->EmitIntValue(0, PtrSize);
604 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
606 OutStreamer->AddBlankLine();
610 MCSymbol *EmittedInitSym = GVSym;
612 OutStreamer->SwitchSection(TheSection);
614 EmitLinkage(GV, EmittedInitSym);
615 EmitAlignment(AlignLog, GV);
617 OutStreamer->EmitLabel(EmittedInitSym);
619 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
621 if (MAI->hasDotTypeDotSizeDirective())
623 OutStreamer->emitELFSize(EmittedInitSym,
624 MCConstantExpr::create(Size, OutContext));
626 OutStreamer->AddBlankLine();
629 /// Emit the directive and value for debug thread local expression
631 /// \p Value - The value to emit.
632 /// \p Size - The size of the integer (in bytes) to emit.
633 void AsmPrinter::EmitDebugValue(const MCExpr *Value, unsigned Size) const {
634 OutStreamer->EmitValue(Value, Size);
637 /// EmitFunctionHeader - This method emits the header for the current
639 void AsmPrinter::EmitFunctionHeader() {
640 const Function &F = MF->getFunction();
643 OutStreamer->GetCommentOS()
644 << "-- Begin function "
645 << GlobalValue::dropLLVMManglingEscape(F.getName()) << '\n';
647 // Print out constants referenced by the function
650 // Print the 'header' of function.
651 OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(&F, TM));
652 EmitVisibility(CurrentFnSym, F.getVisibility());
654 EmitLinkage(&F, CurrentFnSym);
655 if (MAI->hasFunctionAlignment())
656 EmitAlignment(MF->getAlignment(), &F);
658 if (MAI->hasDotTypeDotSizeDirective())
659 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
662 F.printAsOperand(OutStreamer->GetCommentOS(),
663 /*PrintType=*/false, F.getParent());
664 OutStreamer->GetCommentOS() << '\n';
667 // Emit the prefix data.
668 if (F.hasPrefixData()) {
669 if (MAI->hasSubsectionsViaSymbols()) {
670 // Preserving prefix data on platforms which use subsections-via-symbols
671 // is a bit tricky. Here we introduce a symbol for the prefix data
672 // and use the .alt_entry attribute to mark the function's real entry point
673 // as an alternative entry point to the prefix-data symbol.
674 MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
675 OutStreamer->EmitLabel(PrefixSym);
677 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
679 // Emit an .alt_entry directive for the actual function symbol.
680 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
682 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
686 // Emit the CurrentFnSym. This is a virtual function to allow targets to
687 // do their wild and crazy things as required.
688 EmitFunctionEntryLabel();
690 // If the function had address-taken blocks that got deleted, then we have
691 // references to the dangling symbols. Emit them at the start of the function
692 // so that we don't get references to undefined symbols.
693 std::vector<MCSymbol*> DeadBlockSyms;
694 MMI->takeDeletedSymbolsForFunction(&F, DeadBlockSyms);
695 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
696 OutStreamer->AddComment("Address taken block that was later removed");
697 OutStreamer->EmitLabel(DeadBlockSyms[i]);
700 if (CurrentFnBegin) {
701 if (MAI->useAssignmentForEHBegin()) {
702 MCSymbol *CurPos = OutContext.createTempSymbol();
703 OutStreamer->EmitLabel(CurPos);
704 OutStreamer->EmitAssignment(CurrentFnBegin,
705 MCSymbolRefExpr::create(CurPos, OutContext));
707 OutStreamer->EmitLabel(CurrentFnBegin);
711 // Emit pre-function debug and/or EH information.
712 for (const HandlerInfo &HI : Handlers) {
713 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
714 HI.TimerGroupDescription, TimePassesIsEnabled);
715 HI.Handler->beginFunction(MF);
718 // Emit the prologue data.
719 if (F.hasPrologueData())
720 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrologueData());
723 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
724 /// function. This can be overridden by targets as required to do custom stuff.
725 void AsmPrinter::EmitFunctionEntryLabel() {
726 CurrentFnSym->redefineIfPossible();
728 // The function label could have already been emitted if two symbols end up
729 // conflicting due to asm renaming. Detect this and emit an error.
730 if (CurrentFnSym->isVariable())
731 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
732 "' is a protected alias");
733 if (CurrentFnSym->isDefined())
734 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
735 "' label emitted multiple times to assembly file");
737 return OutStreamer->EmitLabel(CurrentFnSym);
740 /// emitComments - Pretty-print comments for instructions.
741 /// It returns true iff the sched comment was emitted.
742 /// Otherwise it returns false.
743 static bool emitComments(const MachineInstr &MI, raw_ostream &CommentOS,
745 const MachineFunction *MF = MI.getMF();
746 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
748 // Check for spills and reloads
751 const MachineFrameInfo &MFI = MF->getFrameInfo();
752 bool Commented = false;
755 [&MFI](const SmallVectorImpl<const MachineMemOperand *> &Accesses) {
757 for (auto A : Accesses)
758 if (MFI.isSpillSlotObjectIndex(
759 cast<FixedStackPseudoSourceValue>(A->getPseudoValue())
761 Size += A->getSize();
765 // We assume a single instruction only has a spill or reload, not
767 const MachineMemOperand *MMO;
768 SmallVector<const MachineMemOperand *, 2> Accesses;
769 if (TII->isLoadFromStackSlotPostFE(MI, FI)) {
770 if (MFI.isSpillSlotObjectIndex(FI)) {
771 MMO = *MI.memoperands_begin();
772 CommentOS << MMO->getSize() << "-byte Reload";
775 } else if (TII->hasLoadFromStackSlot(MI, Accesses)) {
776 if (auto Size = getSize(Accesses)) {
777 CommentOS << Size << "-byte Folded Reload";
780 } else if (TII->isStoreToStackSlotPostFE(MI, FI)) {
781 if (MFI.isSpillSlotObjectIndex(FI)) {
782 MMO = *MI.memoperands_begin();
783 CommentOS << MMO->getSize() << "-byte Spill";
786 } else if (TII->hasStoreToStackSlot(MI, Accesses)) {
787 if (auto Size = getSize(Accesses)) {
788 CommentOS << Size << "-byte Folded Spill";
793 // Check for spill-induced copies
794 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) {
796 CommentOS << " Reload Reuse";
800 if (AP->EnablePrintSchedInfo) {
801 // If any comment was added above and we need sched info comment then add
802 // this new comment just after the above comment w/o "\n" between them.
803 CommentOS << " " << MF->getSubtarget().getSchedInfoStr(MI) << "\n";
811 /// emitImplicitDef - This method emits the specified machine instruction
812 /// that is an implicit def.
813 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
814 unsigned RegNo = MI->getOperand(0).getReg();
816 SmallString<128> Str;
817 raw_svector_ostream OS(Str);
818 OS << "implicit-def: "
819 << printReg(RegNo, MF->getSubtarget().getRegisterInfo());
821 OutStreamer->AddComment(OS.str());
822 OutStreamer->AddBlankLine();
825 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
827 raw_string_ostream OS(Str);
829 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
830 const MachineOperand &Op = MI->getOperand(i);
831 assert(Op.isReg() && "KILL instruction must have only register operands");
832 OS << ' ' << (Op.isDef() ? "def " : "killed ")
833 << printReg(Op.getReg(), AP.MF->getSubtarget().getRegisterInfo());
835 AP.OutStreamer->AddComment(OS.str());
836 AP.OutStreamer->AddBlankLine();
839 /// emitDebugValueComment - This method handles the target-independent form
840 /// of DBG_VALUE, returning true if it was able to do so. A false return
841 /// means the target will need to handle MI in EmitInstruction.
842 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
843 // This code handles only the 4-operand target-independent form.
844 if (MI->getNumOperands() != 4)
847 SmallString<128> Str;
848 raw_svector_ostream OS(Str);
849 OS << "DEBUG_VALUE: ";
851 const DILocalVariable *V = MI->getDebugVariable();
852 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
853 StringRef Name = SP->getName();
860 // The second operand is only an offset if it's an immediate.
861 bool MemLoc = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
862 int64_t Offset = MemLoc ? MI->getOperand(1).getImm() : 0;
863 const DIExpression *Expr = MI->getDebugExpression();
864 if (Expr->getNumElements()) {
866 bool NeedSep = false;
867 for (auto Op : Expr->expr_ops()) {
872 OS << dwarf::OperationEncodingString(Op.getOp());
873 for (unsigned I = 0; I < Op.getNumArgs(); ++I)
874 OS << ' ' << Op.getArg(I);
879 // Register or immediate value. Register 0 means undef.
880 if (MI->getOperand(0).isFPImm()) {
881 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
882 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
883 OS << (double)APF.convertToFloat();
884 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
885 OS << APF.convertToDouble();
887 // There is no good way to print long double. Convert a copy to
888 // double. Ah well, it's only a comment.
890 APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
892 OS << "(long double) " << APF.convertToDouble();
894 } else if (MI->getOperand(0).isImm()) {
895 OS << MI->getOperand(0).getImm();
896 } else if (MI->getOperand(0).isCImm()) {
897 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
900 if (MI->getOperand(0).isReg()) {
901 Reg = MI->getOperand(0).getReg();
903 assert(MI->getOperand(0).isFI() && "Unknown operand type");
904 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
905 Offset += TFI->getFrameIndexReference(*AP.MF,
906 MI->getOperand(0).getIndex(), Reg);
910 // Suppress offset, it is not meaningful here.
912 // NOTE: Want this comment at start of line, don't emit with AddComment.
913 AP.OutStreamer->emitRawComment(OS.str());
918 OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
922 OS << '+' << Offset << ']';
924 // NOTE: Want this comment at start of line, don't emit with AddComment.
925 AP.OutStreamer->emitRawComment(OS.str());
929 /// This method handles the target-independent form of DBG_LABEL, returning
930 /// true if it was able to do so. A false return means the target will need
931 /// to handle MI in EmitInstruction.
932 static bool emitDebugLabelComment(const MachineInstr *MI, AsmPrinter &AP) {
933 if (MI->getNumOperands() != 1)
936 SmallString<128> Str;
937 raw_svector_ostream OS(Str);
938 OS << "DEBUG_LABEL: ";
940 const DILabel *V = MI->getDebugLabel();
941 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
942 StringRef Name = SP->getName();
948 // NOTE: Want this comment at start of line, don't emit with AddComment.
949 AP.OutStreamer->emitRawComment(OS.str());
953 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() const {
954 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
955 MF->getFunction().needsUnwindTableEntry())
958 if (MMI->hasDebugInfo())
964 bool AsmPrinter::needsSEHMoves() {
965 return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry();
968 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
969 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
970 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
971 ExceptionHandlingType != ExceptionHandling::ARM)
974 if (needsCFIMoves() == CFI_M_None)
977 // If there is no "real" instruction following this CFI instruction, skip
978 // emitting it; it would be beyond the end of the function's FDE range.
979 auto *MBB = MI.getParent();
980 auto I = std::next(MI.getIterator());
981 while (I != MBB->end() && I->isTransient())
983 if (I == MBB->instr_end() &&
984 MBB->getReverseIterator() == MBB->getParent()->rbegin())
987 const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions();
988 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
989 const MCCFIInstruction &CFI = Instrs[CFIIndex];
990 emitCFIInstruction(CFI);
993 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
994 // The operands are the MCSymbol and the frame offset of the allocation.
995 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
996 int FrameOffset = MI.getOperand(1).getImm();
998 // Emit a symbol assignment.
999 OutStreamer->EmitAssignment(FrameAllocSym,
1000 MCConstantExpr::create(FrameOffset, OutContext));
1003 void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) {
1004 if (!MF.getTarget().Options.EmitStackSizeSection)
1007 MCSection *StackSizeSection =
1008 getObjFileLowering().getStackSizesSection(*getCurrentSection());
1009 if (!StackSizeSection)
1012 const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
1013 // Don't emit functions with dynamic stack allocations.
1014 if (FrameInfo.hasVarSizedObjects())
1017 OutStreamer->PushSection();
1018 OutStreamer->SwitchSection(StackSizeSection);
1020 const MCSymbol *FunctionSymbol = getFunctionBegin();
1021 uint64_t StackSize = FrameInfo.getStackSize();
1022 OutStreamer->EmitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
1023 OutStreamer->EmitULEB128IntValue(StackSize);
1025 OutStreamer->PopSection();
1028 static bool needFuncLabelsForEHOrDebugInfo(const MachineFunction &MF,
1029 MachineModuleInfo *MMI) {
1030 if (!MF.getLandingPads().empty() || MF.hasEHFunclets() || MMI->hasDebugInfo())
1033 // We might emit an EH table that uses function begin and end labels even if
1034 // we don't have any landingpads.
1035 if (!MF.getFunction().hasPersonalityFn())
1037 return !isNoOpWithoutInvoke(
1038 classifyEHPersonality(MF.getFunction().getPersonalityFn()));
1041 /// EmitFunctionBody - This method emits the body and trailer for a
1043 void AsmPrinter::EmitFunctionBody() {
1044 EmitFunctionHeader();
1046 // Emit target-specific gunk before the function body.
1047 EmitFunctionBodyStart();
1049 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
1052 // Get MachineDominatorTree or compute it on the fly if it's unavailable
1053 MDT = getAnalysisIfAvailable<MachineDominatorTree>();
1055 OwnedMDT = make_unique<MachineDominatorTree>();
1056 OwnedMDT->getBase().recalculate(*MF);
1057 MDT = OwnedMDT.get();
1060 // Get MachineLoopInfo or compute it on the fly if it's unavailable
1061 MLI = getAnalysisIfAvailable<MachineLoopInfo>();
1063 OwnedMLI = make_unique<MachineLoopInfo>();
1064 OwnedMLI->getBase().analyze(MDT->getBase());
1065 MLI = OwnedMLI.get();
1069 // Print out code for the function.
1070 bool HasAnyRealCode = false;
1071 int NumInstsInFunction = 0;
1072 for (auto &MBB : *MF) {
1073 // Print a label for the basic block.
1074 EmitBasicBlockStart(MBB);
1075 for (auto &MI : MBB) {
1076 // Print the assembly for the instruction.
1077 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
1078 !MI.isDebugInstr()) {
1079 HasAnyRealCode = true;
1080 ++NumInstsInFunction;
1083 // If there is a pre-instruction symbol, emit a label for it here.
1084 if (MCSymbol *S = MI.getPreInstrSymbol())
1085 OutStreamer->EmitLabel(S);
1087 if (ShouldPrintDebugScopes) {
1088 for (const HandlerInfo &HI : Handlers) {
1089 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1090 HI.TimerGroupName, HI.TimerGroupDescription,
1091 TimePassesIsEnabled);
1092 HI.Handler->beginInstruction(&MI);
1096 if (isVerbose() && emitComments(MI, OutStreamer->GetCommentOS(), this)) {
1097 MachineInstr *MIP = const_cast<MachineInstr *>(&MI);
1098 MIP->setAsmPrinterFlag(MachineInstr::NoSchedComment);
1101 switch (MI.getOpcode()) {
1102 case TargetOpcode::CFI_INSTRUCTION:
1103 emitCFIInstruction(MI);
1105 case TargetOpcode::LOCAL_ESCAPE:
1108 case TargetOpcode::EH_LABEL:
1109 case TargetOpcode::GC_LABEL:
1110 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
1112 case TargetOpcode::INLINEASM:
1115 case TargetOpcode::DBG_VALUE:
1117 if (!emitDebugValueComment(&MI, *this))
1118 EmitInstruction(&MI);
1121 case TargetOpcode::DBG_LABEL:
1123 if (!emitDebugLabelComment(&MI, *this))
1124 EmitInstruction(&MI);
1127 case TargetOpcode::IMPLICIT_DEF:
1128 if (isVerbose()) emitImplicitDef(&MI);
1130 case TargetOpcode::KILL:
1131 if (isVerbose()) emitKill(&MI, *this);
1134 EmitInstruction(&MI);
1138 // If there is a post-instruction symbol, emit a label for it here.
1139 if (MCSymbol *S = MI.getPostInstrSymbol())
1140 OutStreamer->EmitLabel(S);
1142 if (ShouldPrintDebugScopes) {
1143 for (const HandlerInfo &HI : Handlers) {
1144 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1145 HI.TimerGroupName, HI.TimerGroupDescription,
1146 TimePassesIsEnabled);
1147 HI.Handler->endInstruction();
1152 EmitBasicBlockEnd(MBB);
1155 EmittedInsts += NumInstsInFunction;
1156 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
1157 MF->getFunction().getSubprogram(),
1159 R << ore::NV("NumInstructions", NumInstsInFunction)
1160 << " instructions in function";
1163 // If the function is empty and the object file uses .subsections_via_symbols,
1164 // then we need to emit *something* to the function body to prevent the
1165 // labels from collapsing together. Just emit a noop.
1166 // Similarly, don't emit empty functions on Windows either. It can lead to
1167 // duplicate entries (two functions with the same RVA) in the Guard CF Table
1168 // after linking, causing the kernel not to load the binary:
1169 // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
1170 // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
1171 const Triple &TT = TM.getTargetTriple();
1172 if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() ||
1173 (TT.isOSWindows() && TT.isOSBinFormatCOFF()))) {
1175 MF->getSubtarget().getInstrInfo()->getNoop(Noop);
1177 // Targets can opt-out of emitting the noop here by leaving the opcode
1179 if (Noop.getOpcode()) {
1180 OutStreamer->AddComment("avoids zero-length function");
1181 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
1185 const Function &F = MF->getFunction();
1186 for (const auto &BB : F) {
1187 if (!BB.hasAddressTaken())
1189 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
1190 if (Sym->isDefined())
1192 OutStreamer->AddComment("Address of block that was removed by CodeGen");
1193 OutStreamer->EmitLabel(Sym);
1196 // Emit target-specific gunk after the function body.
1197 EmitFunctionBodyEnd();
1199 if (needFuncLabelsForEHOrDebugInfo(*MF, MMI) ||
1200 MAI->hasDotTypeDotSizeDirective()) {
1201 // Create a symbol for the end of function.
1202 CurrentFnEnd = createTempSymbol("func_end");
1203 OutStreamer->EmitLabel(CurrentFnEnd);
1206 // If the target wants a .size directive for the size of the function, emit
1208 if (MAI->hasDotTypeDotSizeDirective()) {
1209 // We can get the size as difference between the function label and the
1211 const MCExpr *SizeExp = MCBinaryExpr::createSub(
1212 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1213 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1214 OutStreamer->emitELFSize(CurrentFnSym, SizeExp);
1217 for (const HandlerInfo &HI : Handlers) {
1218 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1219 HI.TimerGroupDescription, TimePassesIsEnabled);
1220 HI.Handler->markFunctionEnd();
1223 // Print out jump tables referenced by the function.
1224 EmitJumpTableInfo();
1226 // Emit post-function debug and/or EH information.
1227 for (const HandlerInfo &HI : Handlers) {
1228 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1229 HI.TimerGroupDescription, TimePassesIsEnabled);
1230 HI.Handler->endFunction(MF);
1233 // Emit section containing stack size metadata.
1234 emitStackSizeSection(*MF);
1237 OutStreamer->GetCommentOS() << "-- End function\n";
1239 OutStreamer->AddBlankLine();
1242 /// Compute the number of Global Variables that uses a Constant.
1243 static unsigned getNumGlobalVariableUses(const Constant *C) {
1247 if (isa<GlobalVariable>(C))
1250 unsigned NumUses = 0;
1251 for (auto *CU : C->users())
1252 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1257 /// Only consider global GOT equivalents if at least one user is a
1258 /// cstexpr inside an initializer of another global variables. Also, don't
1259 /// handle cstexpr inside instructions. During global variable emission,
1260 /// candidates are skipped and are emitted later in case at least one cstexpr
1261 /// isn't replaced by a PC relative GOT entry access.
1262 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1263 unsigned &NumGOTEquivUsers) {
1264 // Global GOT equivalents are unnamed private globals with a constant
1265 // pointer initializer to another global symbol. They must point to a
1266 // GlobalVariable or Function, i.e., as GlobalValue.
1267 if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
1268 !GV->isConstant() || !GV->isDiscardableIfUnused() ||
1269 !dyn_cast<GlobalValue>(GV->getOperand(0)))
1272 // To be a got equivalent, at least one of its users need to be a constant
1273 // expression used by another global variable.
1274 for (auto *U : GV->users())
1275 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1277 return NumGOTEquivUsers > 0;
1280 /// Unnamed constant global variables solely contaning a pointer to
1281 /// another globals variable is equivalent to a GOT table entry; it contains the
1282 /// the address of another symbol. Optimize it and replace accesses to these
1283 /// "GOT equivalents" by using the GOT entry for the final global instead.
1284 /// Compute GOT equivalent candidates among all global variables to avoid
1285 /// emitting them if possible later on, after it use is replaced by a GOT entry
1287 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1288 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1291 for (const auto &G : M.globals()) {
1292 unsigned NumGOTEquivUsers = 0;
1293 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1296 const MCSymbol *GOTEquivSym = getSymbol(&G);
1297 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1301 /// Constant expressions using GOT equivalent globals may not be eligible
1302 /// for PC relative GOT entry conversion, in such cases we need to emit such
1303 /// globals we previously omitted in EmitGlobalVariable.
1304 void AsmPrinter::emitGlobalGOTEquivs() {
1305 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1308 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1309 for (auto &I : GlobalGOTEquivs) {
1310 const GlobalVariable *GV = I.second.first;
1311 unsigned Cnt = I.second.second;
1313 FailedCandidates.push_back(GV);
1315 GlobalGOTEquivs.clear();
1317 for (auto *GV : FailedCandidates)
1318 EmitGlobalVariable(GV);
1321 void AsmPrinter::emitGlobalIndirectSymbol(Module &M,
1322 const GlobalIndirectSymbol& GIS) {
1323 MCSymbol *Name = getSymbol(&GIS);
1325 if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective())
1326 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1327 else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage())
1328 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1330 assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage");
1332 // Set the symbol type to function if the alias has a function type.
1333 // This affects codegen when the aliasee is not a function.
1334 if (GIS.getType()->getPointerElementType()->isFunctionTy()) {
1335 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
1336 if (isa<GlobalIFunc>(GIS))
1337 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
1340 EmitVisibility(Name, GIS.getVisibility());
1342 const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol());
1344 if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
1345 OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry);
1347 // Emit the directives as assignments aka .set:
1348 OutStreamer->EmitAssignment(Name, Expr);
1350 if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) {
1351 // If the aliasee does not correspond to a symbol in the output, i.e. the
1352 // alias is not of an object or the aliased object is private, then set the
1353 // size of the alias symbol from the type of the alias. We don't do this in
1354 // other situations as the alias and aliasee having differing types but same
1355 // size may be intentional.
1356 const GlobalObject *BaseObject = GA->getBaseObject();
1357 if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() &&
1358 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1359 const DataLayout &DL = M.getDataLayout();
1360 uint64_t Size = DL.getTypeAllocSize(GA->getValueType());
1361 OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
1366 bool AsmPrinter::doFinalization(Module &M) {
1367 // Set the MachineFunction to nullptr so that we can catch attempted
1368 // accesses to MF specific features at the module level and so that
1369 // we can conditionalize accesses based on whether or not it is nullptr.
1372 // Gather all GOT equivalent globals in the module. We really need two
1373 // passes over the globals: one to compute and another to avoid its emission
1374 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1375 // where the got equivalent shows up before its use.
1376 computeGlobalGOTEquivs(M);
1378 // Emit global variables.
1379 for (const auto &G : M.globals())
1380 EmitGlobalVariable(&G);
1382 // Emit remaining GOT equivalent globals.
1383 emitGlobalGOTEquivs();
1385 // Emit visibility info for declarations
1386 for (const Function &F : M) {
1387 if (!F.isDeclarationForLinker())
1389 GlobalValue::VisibilityTypes V = F.getVisibility();
1390 if (V == GlobalValue::DefaultVisibility)
1393 MCSymbol *Name = getSymbol(&F);
1394 EmitVisibility(Name, V, false);
1397 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1399 TLOF.emitModuleMetadata(*OutStreamer, M);
1401 if (TM.getTargetTriple().isOSBinFormatELF()) {
1402 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1404 // Output stubs for external and common global variables.
1405 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1406 if (!Stubs.empty()) {
1407 OutStreamer->SwitchSection(TLOF.getDataSection());
1408 const DataLayout &DL = M.getDataLayout();
1410 EmitAlignment(Log2_32(DL.getPointerSize()));
1411 for (const auto &Stub : Stubs) {
1412 OutStreamer->EmitLabel(Stub.first);
1413 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1414 DL.getPointerSize());
1419 if (TM.getTargetTriple().isOSBinFormatCOFF()) {
1420 MachineModuleInfoCOFF &MMICOFF =
1421 MMI->getObjFileInfo<MachineModuleInfoCOFF>();
1423 // Output stubs for external and common global variables.
1424 MachineModuleInfoCOFF::SymbolListTy Stubs = MMICOFF.GetGVStubList();
1425 if (!Stubs.empty()) {
1426 const DataLayout &DL = M.getDataLayout();
1428 for (const auto &Stub : Stubs) {
1429 SmallString<256> SectionName = StringRef(".rdata$");
1430 SectionName += Stub.first->getName();
1431 OutStreamer->SwitchSection(OutContext.getCOFFSection(
1433 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
1434 COFF::IMAGE_SCN_LNK_COMDAT,
1435 SectionKind::getReadOnly(), Stub.first->getName(),
1436 COFF::IMAGE_COMDAT_SELECT_ANY));
1437 EmitAlignment(Log2_32(DL.getPointerSize()));
1438 OutStreamer->EmitSymbolAttribute(Stub.first, MCSA_Global);
1439 OutStreamer->EmitLabel(Stub.first);
1440 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1441 DL.getPointerSize());
1446 // Finalize debug and EH information.
1447 for (const HandlerInfo &HI : Handlers) {
1448 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1449 HI.TimerGroupDescription, TimePassesIsEnabled);
1450 HI.Handler->endModule();
1456 // If the target wants to know about weak references, print them all.
1457 if (MAI->getWeakRefDirective()) {
1458 // FIXME: This is not lazy, it would be nice to only print weak references
1459 // to stuff that is actually used. Note that doing so would require targets
1460 // to notice uses in operands (due to constant exprs etc). This should
1461 // happen with the MC stuff eventually.
1463 // Print out module-level global objects here.
1464 for (const auto &GO : M.global_objects()) {
1465 if (!GO.hasExternalWeakLinkage())
1467 OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
1471 OutStreamer->AddBlankLine();
1473 // Print aliases in topological order, that is, for each alias a = b,
1474 // b must be printed before a.
1475 // This is because on some targets (e.g. PowerPC) linker expects aliases in
1476 // such an order to generate correct TOC information.
1477 SmallVector<const GlobalAlias *, 16> AliasStack;
1478 SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
1479 for (const auto &Alias : M.aliases()) {
1480 for (const GlobalAlias *Cur = &Alias; Cur;
1481 Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
1482 if (!AliasVisited.insert(Cur).second)
1484 AliasStack.push_back(Cur);
1486 for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
1487 emitGlobalIndirectSymbol(M, *AncestorAlias);
1490 for (const auto &IFunc : M.ifuncs())
1491 emitGlobalIndirectSymbol(M, IFunc);
1493 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1494 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1495 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1496 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1497 MP->finishAssembly(M, *MI, *this);
1499 // Emit llvm.ident metadata in an '.ident' directive.
1500 EmitModuleIdents(M);
1502 // Emit bytes for llvm.commandline metadata.
1503 EmitModuleCommandLines(M);
1505 // Emit __morestack address if needed for indirect calls.
1506 if (MMI->usesMorestackAddr()) {
1508 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1509 getDataLayout(), SectionKind::getReadOnly(),
1510 /*C=*/nullptr, Align);
1511 OutStreamer->SwitchSection(ReadOnlySection);
1513 MCSymbol *AddrSymbol =
1514 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1515 OutStreamer->EmitLabel(AddrSymbol);
1517 unsigned PtrSize = MAI->getCodePointerSize();
1518 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1522 // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if
1523 // split-stack is used.
1524 if (TM.getTargetTriple().isOSBinFormatELF() && MMI->hasSplitStack()) {
1525 OutStreamer->SwitchSection(
1526 OutContext.getELFSection(".note.GNU-split-stack", ELF::SHT_PROGBITS, 0));
1527 if (MMI->hasNosplitStack())
1528 OutStreamer->SwitchSection(
1529 OutContext.getELFSection(".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0));
1532 // If we don't have any trampolines, then we don't require stack memory
1533 // to be executable. Some targets have a directive to declare this.
1534 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1535 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1536 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1537 OutStreamer->SwitchSection(S);
1539 if (TM.getTargetTriple().isOSBinFormatCOFF()) {
1540 // Emit /EXPORT: flags for each exported global as necessary.
1541 const auto &TLOF = getObjFileLowering();
1544 for (const GlobalValue &GV : M.global_values()) {
1545 raw_string_ostream OS(Flags);
1546 TLOF.emitLinkerFlagsForGlobal(OS, &GV);
1548 if (!Flags.empty()) {
1549 OutStreamer->SwitchSection(TLOF.getDrectveSection());
1550 OutStreamer->EmitBytes(Flags);
1555 // Emit /INCLUDE: flags for each used global as necessary.
1556 if (const auto *LU = M.getNamedGlobal("llvm.used")) {
1557 assert(LU->hasInitializer() &&
1558 "expected llvm.used to have an initializer");
1559 assert(isa<ArrayType>(LU->getValueType()) &&
1560 "expected llvm.used to be an array type");
1561 if (const auto *A = cast<ConstantArray>(LU->getInitializer())) {
1562 for (const Value *Op : A->operands()) {
1564 cast<GlobalValue>(Op->stripPointerCastsNoFollowAliases());
1565 // Global symbols with internal or private linkage are not visible to
1566 // the linker, and thus would cause an error when the linker tried to
1567 // preserve the symbol due to the `/include:` directive.
1568 if (GV->hasLocalLinkage())
1571 raw_string_ostream OS(Flags);
1572 TLOF.emitLinkerFlagsForUsed(OS, GV);
1575 if (!Flags.empty()) {
1576 OutStreamer->SwitchSection(TLOF.getDrectveSection());
1577 OutStreamer->EmitBytes(Flags);
1585 if (TM.Options.EmitAddrsig) {
1586 // Emit address-significance attributes for all globals.
1587 OutStreamer->EmitAddrsig();
1588 for (const GlobalValue &GV : M.global_values())
1589 if (!GV.use_empty() && !GV.isThreadLocal() &&
1590 !GV.hasDLLImportStorageClass() && !GV.getName().startswith("llvm.") &&
1591 !GV.hasAtLeastLocalUnnamedAddr())
1592 OutStreamer->EmitAddrsigSym(getSymbol(&GV));
1595 // Allow the target to emit any magic that it wants at the end of the file,
1596 // after everything else has gone out.
1597 EmitEndOfAsmFile(M);
1601 OutStreamer->Finish();
1602 OutStreamer->reset();
1609 MCSymbol *AsmPrinter::getCurExceptionSym() {
1610 if (!CurExceptionSym)
1611 CurExceptionSym = createTempSymbol("exception");
1612 return CurExceptionSym;
1615 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1617 // Get the function symbol.
1618 CurrentFnSym = getSymbol(&MF.getFunction());
1619 CurrentFnSymForSize = CurrentFnSym;
1620 CurrentFnBegin = nullptr;
1621 CurExceptionSym = nullptr;
1622 bool NeedsLocalForSize = MAI->needsLocalForSize();
1623 if (needFuncLabelsForEHOrDebugInfo(MF, MMI) || NeedsLocalForSize ||
1624 MF.getTarget().Options.EmitStackSizeSection) {
1625 CurrentFnBegin = createTempSymbol("func_begin");
1626 if (NeedsLocalForSize)
1627 CurrentFnSymForSize = CurrentFnBegin;
1630 ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
1632 const TargetSubtargetInfo &STI = MF.getSubtarget();
1633 EnablePrintSchedInfo = PrintSchedule.getNumOccurrences()
1635 : STI.supportPrintSchedInfo();
1640 // Keep track the alignment, constpool entries per Section.
1644 SmallVector<unsigned, 4> CPEs;
1646 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1649 } // end anonymous namespace
1651 /// EmitConstantPool - Print to the current output stream assembly
1652 /// representations of the constants in the constant pool MCP. This is
1653 /// used to print out constants which have been "spilled to memory" by
1654 /// the code generator.
1655 void AsmPrinter::EmitConstantPool() {
1656 const MachineConstantPool *MCP = MF->getConstantPool();
1657 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1658 if (CP.empty()) return;
1660 // Calculate sections for constant pool entries. We collect entries to go into
1661 // the same section together to reduce amount of section switch statements.
1662 SmallVector<SectionCPs, 4> CPSections;
1663 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1664 const MachineConstantPoolEntry &CPE = CP[i];
1665 unsigned Align = CPE.getAlignment();
1667 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1669 const Constant *C = nullptr;
1670 if (!CPE.isMachineConstantPoolEntry())
1671 C = CPE.Val.ConstVal;
1673 MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
1676 // The number of sections are small, just do a linear search from the
1677 // last section to the first.
1679 unsigned SecIdx = CPSections.size();
1680 while (SecIdx != 0) {
1681 if (CPSections[--SecIdx].S == S) {
1687 SecIdx = CPSections.size();
1688 CPSections.push_back(SectionCPs(S, Align));
1691 if (Align > CPSections[SecIdx].Alignment)
1692 CPSections[SecIdx].Alignment = Align;
1693 CPSections[SecIdx].CPEs.push_back(i);
1696 // Now print stuff into the calculated sections.
1697 const MCSection *CurSection = nullptr;
1698 unsigned Offset = 0;
1699 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1700 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1701 unsigned CPI = CPSections[i].CPEs[j];
1702 MCSymbol *Sym = GetCPISymbol(CPI);
1703 if (!Sym->isUndefined())
1706 if (CurSection != CPSections[i].S) {
1707 OutStreamer->SwitchSection(CPSections[i].S);
1708 EmitAlignment(Log2_32(CPSections[i].Alignment));
1709 CurSection = CPSections[i].S;
1713 MachineConstantPoolEntry CPE = CP[CPI];
1715 // Emit inter-object padding for alignment.
1716 unsigned AlignMask = CPE.getAlignment() - 1;
1717 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1718 OutStreamer->EmitZeros(NewOffset - Offset);
1720 Type *Ty = CPE.getType();
1721 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1723 OutStreamer->EmitLabel(Sym);
1724 if (CPE.isMachineConstantPoolEntry())
1725 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1727 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1732 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1733 /// by the current function to the current output stream.
1734 void AsmPrinter::EmitJumpTableInfo() {
1735 const DataLayout &DL = MF->getDataLayout();
1736 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1738 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1739 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1740 if (JT.empty()) return;
1742 // Pick the directive to use to print the jump table entries, and switch to
1743 // the appropriate section.
1744 const Function &F = MF->getFunction();
1745 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1746 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1747 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1749 if (JTInDiffSection) {
1750 // Drop it in the readonly section.
1751 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM);
1752 OutStreamer->SwitchSection(ReadOnlySection);
1755 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1757 // Jump tables in code sections are marked with a data_region directive
1758 // where that's supported.
1759 if (!JTInDiffSection)
1760 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1762 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1763 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1765 // If this jump table was deleted, ignore it.
1766 if (JTBBs.empty()) continue;
1768 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1769 /// emit a .set directive for each unique entry.
1770 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1771 MAI->doesSetDirectiveSuppressReloc()) {
1772 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1773 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1774 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1775 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1776 const MachineBasicBlock *MBB = JTBBs[ii];
1777 if (!EmittedSets.insert(MBB).second)
1780 // .set LJTSet, LBB32-base
1782 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1783 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1784 MCBinaryExpr::createSub(LHS, Base,
1789 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1790 // before each jump table. The first label is never referenced, but tells
1791 // the assembler and linker the extents of the jump table object. The
1792 // second label is actually referenced by the code.
1793 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1794 // FIXME: This doesn't have to have any specific name, just any randomly
1795 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1796 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1798 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1800 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1801 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1803 if (!JTInDiffSection)
1804 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1807 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1809 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1810 const MachineBasicBlock *MBB,
1811 unsigned UID) const {
1812 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1813 const MCExpr *Value = nullptr;
1814 switch (MJTI->getEntryKind()) {
1815 case MachineJumpTableInfo::EK_Inline:
1816 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1817 case MachineJumpTableInfo::EK_Custom32:
1818 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1819 MJTI, MBB, UID, OutContext);
1821 case MachineJumpTableInfo::EK_BlockAddress:
1822 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1824 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1826 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1827 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1828 // with a relocation as gp-relative, e.g.:
1830 MCSymbol *MBBSym = MBB->getSymbol();
1831 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1835 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1836 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1837 // with a relocation as gp-relative, e.g.:
1839 MCSymbol *MBBSym = MBB->getSymbol();
1840 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1844 case MachineJumpTableInfo::EK_LabelDifference32: {
1845 // Each entry is the address of the block minus the address of the jump
1846 // table. This is used for PIC jump tables where gprel32 is not supported.
1848 // .word LBB123 - LJTI1_2
1849 // If the .set directive avoids relocations, this is emitted as:
1850 // .set L4_5_set_123, LBB123 - LJTI1_2
1851 // .word L4_5_set_123
1852 if (MAI->doesSetDirectiveSuppressReloc()) {
1853 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1857 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1858 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1859 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1860 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1865 assert(Value && "Unknown entry kind!");
1867 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1868 OutStreamer->EmitValue(Value, EntrySize);
1871 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1872 /// special global used by LLVM. If so, emit it and return true, otherwise
1873 /// do nothing and return false.
1874 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1875 if (GV->getName() == "llvm.used") {
1876 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1877 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1881 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1882 if (GV->getSection() == "llvm.metadata" ||
1883 GV->hasAvailableExternallyLinkage())
1886 if (!GV->hasAppendingLinkage()) return false;
1888 assert(GV->hasInitializer() && "Not a special LLVM global!");
1890 if (GV->getName() == "llvm.global_ctors") {
1891 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1897 if (GV->getName() == "llvm.global_dtors") {
1898 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1899 /* isCtor */ false);
1904 report_fatal_error("unknown special variable");
1907 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1908 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1909 /// is true, as being used with this directive.
1910 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1911 // Should be an array of 'i8*'.
1912 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1913 const GlobalValue *GV =
1914 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1916 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1924 Constant *Func = nullptr;
1925 GlobalValue *ComdatKey = nullptr;
1927 Structor() = default;
1930 } // end anonymous namespace
1932 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1934 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1936 // Should be an array of '{ int, void ()* }' structs. The first value is the
1938 if (!isa<ConstantArray>(List)) return;
1940 // Sanity check the structors list.
1941 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1942 if (!InitList) return; // Not an array!
1943 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1944 // FIXME: Only allow the 3-field form in LLVM 4.0.
1945 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1946 return; // Not an array of two or three elements!
1947 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1948 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1949 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1950 return; // Not (int, ptr, ptr).
1952 // Gather the structors in a form that's convenient for sorting by priority.
1953 SmallVector<Structor, 8> Structors;
1954 for (Value *O : InitList->operands()) {
1955 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1956 if (!CS) continue; // Malformed.
1957 if (CS->getOperand(1)->isNullValue())
1958 break; // Found a null terminator, skip the rest.
1959 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1960 if (!Priority) continue; // Malformed.
1961 Structors.push_back(Structor());
1962 Structor &S = Structors.back();
1963 S.Priority = Priority->getLimitedValue(65535);
1964 S.Func = CS->getOperand(1);
1965 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1967 dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1970 // Emit the function pointers in the target-specific order
1971 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1972 std::stable_sort(Structors.begin(), Structors.end(),
1973 [](const Structor &L,
1974 const Structor &R) { return L.Priority < R.Priority; });
1975 for (Structor &S : Structors) {
1976 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1977 const MCSymbol *KeySym = nullptr;
1978 if (GlobalValue *GV = S.ComdatKey) {
1979 if (GV->isDeclarationForLinker())
1980 // If the associated variable is not defined in this module
1981 // (it might be available_externally, or have been an
1982 // available_externally definition that was dropped by the
1983 // EliminateAvailableExternally pass), some other TU
1984 // will provide its dynamic initializer.
1987 KeySym = getSymbol(GV);
1989 MCSection *OutputSection =
1990 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1991 : Obj.getStaticDtorSection(S.Priority, KeySym));
1992 OutStreamer->SwitchSection(OutputSection);
1993 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1994 EmitAlignment(Align);
1995 EmitXXStructor(DL, S.Func);
1999 void AsmPrinter::EmitModuleIdents(Module &M) {
2000 if (!MAI->hasIdentDirective())
2003 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
2004 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
2005 const MDNode *N = NMD->getOperand(i);
2006 assert(N->getNumOperands() == 1 &&
2007 "llvm.ident metadata entry can have only one operand");
2008 const MDString *S = cast<MDString>(N->getOperand(0));
2009 OutStreamer->EmitIdent(S->getString());
2014 void AsmPrinter::EmitModuleCommandLines(Module &M) {
2015 MCSection *CommandLine = getObjFileLowering().getSectionForCommandLines();
2019 const NamedMDNode *NMD = M.getNamedMetadata("llvm.commandline");
2020 if (!NMD || !NMD->getNumOperands())
2023 OutStreamer->PushSection();
2024 OutStreamer->SwitchSection(CommandLine);
2025 OutStreamer->EmitZeros(1);
2026 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
2027 const MDNode *N = NMD->getOperand(i);
2028 assert(N->getNumOperands() == 1 &&
2029 "llvm.commandline metadata entry can have only one operand");
2030 const MDString *S = cast<MDString>(N->getOperand(0));
2031 OutStreamer->EmitBytes(S->getString());
2032 OutStreamer->EmitZeros(1);
2034 OutStreamer->PopSection();
2037 //===--------------------------------------------------------------------===//
2038 // Emission and print routines
2041 /// Emit a byte directive and value.
2043 void AsmPrinter::emitInt8(int Value) const {
2044 OutStreamer->EmitIntValue(Value, 1);
2047 /// Emit a short directive and value.
2048 void AsmPrinter::emitInt16(int Value) const {
2049 OutStreamer->EmitIntValue(Value, 2);
2052 /// Emit a long directive and value.
2053 void AsmPrinter::emitInt32(int Value) const {
2054 OutStreamer->EmitIntValue(Value, 4);
2057 /// Emit a long long directive and value.
2058 void AsmPrinter::emitInt64(uint64_t Value) const {
2059 OutStreamer->EmitIntValue(Value, 8);
2062 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
2063 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
2064 /// .set if it avoids relocations.
2065 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
2066 unsigned Size) const {
2067 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
2070 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
2071 /// where the size in bytes of the directive is specified by Size and Label
2072 /// specifies the label. This implicitly uses .set if it is available.
2073 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
2075 bool IsSectionRelative) const {
2076 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
2077 OutStreamer->EmitCOFFSecRel32(Label, Offset);
2079 OutStreamer->EmitZeros(Size - 4);
2083 // Emit Label+Offset (or just Label if Offset is zero)
2084 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
2086 Expr = MCBinaryExpr::createAdd(
2087 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
2089 OutStreamer->EmitValue(Expr, Size);
2092 //===----------------------------------------------------------------------===//
2094 // EmitAlignment - Emit an alignment directive to the specified power of
2095 // two boundary. For example, if you pass in 3 here, you will get an 8
2096 // byte alignment. If a global value is specified, and if that global has
2097 // an explicit alignment requested, it will override the alignment request
2098 // if required for correctness.
2099 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
2101 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
2103 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
2106 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
2107 "undefined behavior");
2108 if (getCurrentSection()->getKind().isText())
2109 OutStreamer->EmitCodeAlignment(1u << NumBits);
2111 OutStreamer->EmitValueToAlignment(1u << NumBits);
2114 //===----------------------------------------------------------------------===//
2115 // Constant emission.
2116 //===----------------------------------------------------------------------===//
2118 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
2119 MCContext &Ctx = OutContext;
2121 if (CV->isNullValue() || isa<UndefValue>(CV))
2122 return MCConstantExpr::create(0, Ctx);
2124 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
2125 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
2127 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
2128 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
2130 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
2131 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
2133 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
2135 llvm_unreachable("Unknown constant value to lower!");
2138 switch (CE->getOpcode()) {
2140 // If the code isn't optimized, there may be outstanding folding
2141 // opportunities. Attempt to fold the expression using DataLayout as a
2142 // last resort before giving up.
2143 if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
2145 return lowerConstant(C);
2147 // Otherwise report the problem to the user.
2150 raw_string_ostream OS(S);
2151 OS << "Unsupported expression in static initializer: ";
2152 CE->printAsOperand(OS, /*PrintType=*/false,
2153 !MF ? nullptr : MF->getFunction().getParent());
2154 report_fatal_error(OS.str());
2156 case Instruction::GetElementPtr: {
2157 // Generate a symbolic expression for the byte address
2158 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
2159 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
2161 const MCExpr *Base = lowerConstant(CE->getOperand(0));
2165 int64_t Offset = OffsetAI.getSExtValue();
2166 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
2170 case Instruction::Trunc:
2171 // We emit the value and depend on the assembler to truncate the generated
2172 // expression properly. This is important for differences between
2173 // blockaddress labels. Since the two labels are in the same function, it
2174 // is reasonable to treat their delta as a 32-bit value.
2176 case Instruction::BitCast:
2177 return lowerConstant(CE->getOperand(0));
2179 case Instruction::IntToPtr: {
2180 const DataLayout &DL = getDataLayout();
2182 // Handle casts to pointers by changing them into casts to the appropriate
2183 // integer type. This promotes constant folding and simplifies this code.
2184 Constant *Op = CE->getOperand(0);
2185 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
2187 return lowerConstant(Op);
2190 case Instruction::PtrToInt: {
2191 const DataLayout &DL = getDataLayout();
2193 // Support only foldable casts to/from pointers that can be eliminated by
2194 // changing the pointer to the appropriately sized integer type.
2195 Constant *Op = CE->getOperand(0);
2196 Type *Ty = CE->getType();
2198 const MCExpr *OpExpr = lowerConstant(Op);
2200 // We can emit the pointer value into this slot if the slot is an
2201 // integer slot equal to the size of the pointer.
2202 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
2205 // Otherwise the pointer is smaller than the resultant integer, mask off
2206 // the high bits so we are sure to get a proper truncation if the input is
2208 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
2209 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
2210 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
2213 case Instruction::Sub: {
2216 if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
2220 if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
2222 const MCExpr *RelocExpr =
2223 getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM);
2225 RelocExpr = MCBinaryExpr::createSub(
2226 MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx),
2227 MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
2228 int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
2230 RelocExpr = MCBinaryExpr::createAdd(
2231 RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
2239 // The MC library also has a right-shift operator, but it isn't consistently
2240 // signed or unsigned between different targets.
2241 case Instruction::Add:
2242 case Instruction::Mul:
2243 case Instruction::SDiv:
2244 case Instruction::SRem:
2245 case Instruction::Shl:
2246 case Instruction::And:
2247 case Instruction::Or:
2248 case Instruction::Xor: {
2249 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
2250 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
2251 switch (CE->getOpcode()) {
2252 default: llvm_unreachable("Unknown binary operator constant cast expr");
2253 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
2254 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
2255 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
2256 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
2257 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
2258 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
2259 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
2260 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
2261 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
2267 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
2269 const Constant *BaseCV = nullptr,
2270 uint64_t Offset = 0);
2272 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
2273 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP);
2275 /// isRepeatedByteSequence - Determine whether the given value is
2276 /// composed of a repeated sequence of identical bytes and return the
2277 /// byte value. If it is not a repeated sequence, return -1.
2278 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
2279 StringRef Data = V->getRawDataValues();
2280 assert(!Data.empty() && "Empty aggregates should be CAZ node");
2282 for (unsigned i = 1, e = Data.size(); i != e; ++i)
2283 if (Data[i] != C) return -1;
2284 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
2287 /// isRepeatedByteSequence - Determine whether the given value is
2288 /// composed of a repeated sequence of identical bytes and return the
2289 /// byte value. If it is not a repeated sequence, return -1.
2290 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
2291 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
2292 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
2293 assert(Size % 8 == 0);
2295 // Extend the element to take zero padding into account.
2296 APInt Value = CI->getValue().zextOrSelf(Size);
2297 if (!Value.isSplat(8))
2300 return Value.zextOrTrunc(8).getZExtValue();
2302 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
2303 // Make sure all array elements are sequences of the same repeated
2305 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
2306 Constant *Op0 = CA->getOperand(0);
2307 int Byte = isRepeatedByteSequence(Op0, DL);
2311 // All array elements must be equal.
2312 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
2313 if (CA->getOperand(i) != Op0)
2318 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
2319 return isRepeatedByteSequence(CDS);
2324 static void emitGlobalConstantDataSequential(const DataLayout &DL,
2325 const ConstantDataSequential *CDS,
2327 // See if we can aggregate this into a .fill, if so, emit it as such.
2328 int Value = isRepeatedByteSequence(CDS, DL);
2330 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
2331 // Don't emit a 1-byte object as a .fill.
2333 return AP.OutStreamer->emitFill(Bytes, Value);
2336 // If this can be emitted with .ascii/.asciz, emit it as such.
2337 if (CDS->isString())
2338 return AP.OutStreamer->EmitBytes(CDS->getAsString());
2340 // Otherwise, emit the values in successive locations.
2341 unsigned ElementByteSize = CDS->getElementByteSize();
2342 if (isa<IntegerType>(CDS->getElementType())) {
2343 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
2345 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2346 CDS->getElementAsInteger(i));
2347 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
2351 Type *ET = CDS->getElementType();
2352 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I)
2353 emitGlobalConstantFP(CDS->getElementAsAPFloat(I), ET, AP);
2356 unsigned Size = DL.getTypeAllocSize(CDS->getType());
2357 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
2358 CDS->getNumElements();
2359 assert(EmittedSize <= Size && "Size cannot be less than EmittedSize!");
2360 if (unsigned Padding = Size - EmittedSize)
2361 AP.OutStreamer->EmitZeros(Padding);
2364 static void emitGlobalConstantArray(const DataLayout &DL,
2365 const ConstantArray *CA, AsmPrinter &AP,
2366 const Constant *BaseCV, uint64_t Offset) {
2367 // See if we can aggregate some values. Make sure it can be
2368 // represented as a series of bytes of the constant value.
2369 int Value = isRepeatedByteSequence(CA, DL);
2372 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2373 AP.OutStreamer->emitFill(Bytes, Value);
2376 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2377 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2378 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2383 static void emitGlobalConstantVector(const DataLayout &DL,
2384 const ConstantVector *CV, AsmPrinter &AP) {
2385 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2386 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2388 unsigned Size = DL.getTypeAllocSize(CV->getType());
2389 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2390 CV->getType()->getNumElements();
2391 if (unsigned Padding = Size - EmittedSize)
2392 AP.OutStreamer->EmitZeros(Padding);
2395 static void emitGlobalConstantStruct(const DataLayout &DL,
2396 const ConstantStruct *CS, AsmPrinter &AP,
2397 const Constant *BaseCV, uint64_t Offset) {
2398 // Print the fields in successive locations. Pad to align if needed!
2399 unsigned Size = DL.getTypeAllocSize(CS->getType());
2400 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2401 uint64_t SizeSoFar = 0;
2402 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2403 const Constant *Field = CS->getOperand(i);
2405 // Print the actual field value.
2406 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2408 // Check if padding is needed and insert one or more 0s.
2409 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2410 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2411 - Layout->getElementOffset(i)) - FieldSize;
2412 SizeSoFar += FieldSize + PadSize;
2414 // Insert padding - this may include padding to increase the size of the
2415 // current field up to the ABI size (if the struct is not packed) as well
2416 // as padding to ensure that the next field starts at the right offset.
2417 AP.OutStreamer->EmitZeros(PadSize);
2419 assert(SizeSoFar == Layout->getSizeInBytes() &&
2420 "Layout of constant struct may be incorrect!");
2423 static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP) {
2424 APInt API = APF.bitcastToAPInt();
2426 // First print a comment with what we think the original floating-point value
2427 // should have been.
2428 if (AP.isVerbose()) {
2429 SmallString<8> StrVal;
2430 APF.toString(StrVal);
2433 ET->print(AP.OutStreamer->GetCommentOS());
2435 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2436 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2439 // Now iterate through the APInt chunks, emitting them in endian-correct
2440 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2442 unsigned NumBytes = API.getBitWidth() / 8;
2443 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2444 const uint64_t *p = API.getRawData();
2446 // PPC's long double has odd notions of endianness compared to how LLVM
2447 // handles it: p[0] goes first for *big* endian on PPC.
2448 if (AP.getDataLayout().isBigEndian() && !ET->isPPC_FP128Ty()) {
2449 int Chunk = API.getNumWords() - 1;
2452 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2454 for (; Chunk >= 0; --Chunk)
2455 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2458 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2459 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2462 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2465 // Emit the tail padding for the long double.
2466 const DataLayout &DL = AP.getDataLayout();
2467 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(ET) - DL.getTypeStoreSize(ET));
2470 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2471 emitGlobalConstantFP(CFP->getValueAPF(), CFP->getType(), AP);
2474 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2475 const DataLayout &DL = AP.getDataLayout();
2476 unsigned BitWidth = CI->getBitWidth();
2478 // Copy the value as we may massage the layout for constants whose bit width
2479 // is not a multiple of 64-bits.
2480 APInt Realigned(CI->getValue());
2481 uint64_t ExtraBits = 0;
2482 unsigned ExtraBitsSize = BitWidth & 63;
2484 if (ExtraBitsSize) {
2485 // The bit width of the data is not a multiple of 64-bits.
2486 // The extra bits are expected to be at the end of the chunk of the memory.
2488 // * Nothing to be done, just record the extra bits to emit.
2490 // * Record the extra bits to emit.
2491 // * Realign the raw data to emit the chunks of 64-bits.
2492 if (DL.isBigEndian()) {
2493 // Basically the structure of the raw data is a chunk of 64-bits cells:
2494 // 0 1 BitWidth / 64
2495 // [chunk1][chunk2] ... [chunkN].
2496 // The most significant chunk is chunkN and it should be emitted first.
2497 // However, due to the alignment issue chunkN contains useless bits.
2498 // Realign the chunks so that they contain only useless information:
2499 // ExtraBits 0 1 (BitWidth / 64) - 1
2500 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2501 ExtraBits = Realigned.getRawData()[0] &
2502 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2503 Realigned.lshrInPlace(ExtraBitsSize);
2505 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2508 // We don't expect assemblers to support integer data directives
2509 // for more than 64 bits, so we emit the data in at most 64-bit
2510 // quantities at a time.
2511 const uint64_t *RawData = Realigned.getRawData();
2512 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2513 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2514 AP.OutStreamer->EmitIntValue(Val, 8);
2517 if (ExtraBitsSize) {
2518 // Emit the extra bits after the 64-bits chunks.
2520 // Emit a directive that fills the expected size.
2521 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2522 Size -= (BitWidth / 64) * 8;
2523 assert(Size && Size * 8 >= ExtraBitsSize &&
2524 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2525 == ExtraBits && "Directive too small for extra bits.");
2526 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2530 /// Transform a not absolute MCExpr containing a reference to a GOT
2531 /// equivalent global, by a target specific GOT pc relative access to the
2533 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2534 const Constant *BaseCst,
2536 // The global @foo below illustrates a global that uses a got equivalent.
2538 // @bar = global i32 42
2539 // @gotequiv = private unnamed_addr constant i32* @bar
2540 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2541 // i64 ptrtoint (i32* @foo to i64))
2544 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2545 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2548 // foo = cstexpr, where
2549 // cstexpr := <gotequiv> - "." + <cst>
2550 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2552 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2554 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2555 // gotpcrelcst := <offset from @foo base> + <cst>
2557 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2559 const MCSymbolRefExpr *SymA = MV.getSymA();
2563 // Check that GOT equivalent symbol is cached.
2564 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2565 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2568 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2572 // Check for a valid base symbol
2573 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2574 const MCSymbolRefExpr *SymB = MV.getSymB();
2576 if (!SymB || BaseSym != &SymB->getSymbol())
2579 // Make sure to match:
2581 // gotpcrelcst := <offset from @foo base> + <cst>
2583 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2584 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2585 // if the target knows how to encode it.
2586 int64_t GOTPCRelCst = Offset + MV.getConstant();
2587 if (GOTPCRelCst < 0)
2589 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2592 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2599 // .long gotequiv - "." + <cst>
2601 // is replaced by the target specific equivalent to:
2606 // .long bar@GOTPCREL+<gotpcrelcst>
2607 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2608 const GlobalVariable *GV = Result.first;
2609 int NumUses = (int)Result.second;
2610 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2611 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2612 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2613 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2615 // Update GOT equivalent usage information
2618 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2621 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2622 AsmPrinter &AP, const Constant *BaseCV,
2624 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2626 // Globals with sub-elements such as combinations of arrays and structs
2627 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2628 // constant symbol base and the current position with BaseCV and Offset.
2629 if (!BaseCV && CV->hasOneUse())
2630 BaseCV = dyn_cast<Constant>(CV->user_back());
2632 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2633 return AP.OutStreamer->EmitZeros(Size);
2635 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2642 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2643 CI->getZExtValue());
2644 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2647 emitGlobalConstantLargeInt(CI, AP);
2652 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2653 return emitGlobalConstantFP(CFP, AP);
2655 if (isa<ConstantPointerNull>(CV)) {
2656 AP.OutStreamer->EmitIntValue(0, Size);
2660 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2661 return emitGlobalConstantDataSequential(DL, CDS, AP);
2663 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2664 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2666 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2667 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2669 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2670 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2672 if (CE->getOpcode() == Instruction::BitCast)
2673 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2676 // If the constant expression's size is greater than 64-bits, then we have
2677 // to emit the value in chunks. Try to constant fold the value and emit it
2679 Constant *New = ConstantFoldConstant(CE, DL);
2680 if (New && New != CE)
2681 return emitGlobalConstantImpl(DL, New, AP);
2685 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2686 return emitGlobalConstantVector(DL, V, AP);
2688 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2689 // thread the streamer with EmitValue.
2690 const MCExpr *ME = AP.lowerConstant(CV);
2692 // Since lowerConstant already folded and got rid of all IR pointer and
2693 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2695 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2696 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2698 AP.OutStreamer->EmitValue(ME, Size);
2701 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2702 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2703 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2705 emitGlobalConstantImpl(DL, CV, *this);
2706 else if (MAI->hasSubsectionsViaSymbols()) {
2707 // If the global has zero size, emit a single byte so that two labels don't
2708 // look like they are at the same location.
2709 OutStreamer->EmitIntValue(0, 1);
2713 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2714 // Target doesn't support this yet!
2715 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2718 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2720 OS << '+' << Offset;
2721 else if (Offset < 0)
2725 //===----------------------------------------------------------------------===//
2726 // Symbol Lowering Routines.
2727 //===----------------------------------------------------------------------===//
2729 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2730 return OutContext.createTempSymbol(Name, true);
2733 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2734 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2737 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2738 return MMI->getAddrLabelSymbol(BB);
2741 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2742 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2743 if (getSubtargetInfo().getTargetTriple().isKnownWindowsMSVCEnvironment()) {
2744 const MachineConstantPoolEntry &CPE =
2745 MF->getConstantPool()->getConstants()[CPID];
2746 if (!CPE.isMachineConstantPoolEntry()) {
2747 const DataLayout &DL = MF->getDataLayout();
2748 SectionKind Kind = CPE.getSectionKind(&DL);
2749 const Constant *C = CPE.Val.ConstVal;
2750 unsigned Align = CPE.Alignment;
2751 if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
2752 getObjFileLowering().getSectionForConstant(DL, Kind, C, Align))) {
2753 if (MCSymbol *Sym = S->getCOMDATSymbol()) {
2754 if (Sym->isUndefined())
2755 OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global);
2762 const DataLayout &DL = getDataLayout();
2763 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2764 "CPI" + Twine(getFunctionNumber()) + "_" +
2768 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2769 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2770 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2773 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2774 /// FIXME: privatize to AsmPrinter.
2775 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2776 const DataLayout &DL = getDataLayout();
2777 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2778 Twine(getFunctionNumber()) + "_" +
2779 Twine(UID) + "_set_" + Twine(MBBID));
2782 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2783 StringRef Suffix) const {
2784 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM);
2787 /// Return the MCSymbol for the specified ExternalSymbol.
2788 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2789 SmallString<60> NameStr;
2790 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2791 return OutContext.getOrCreateSymbol(NameStr);
2794 /// PrintParentLoopComment - Print comments about parent loops of this one.
2795 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2796 unsigned FunctionNumber) {
2798 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2799 OS.indent(Loop->getLoopDepth()*2)
2800 << "Parent Loop BB" << FunctionNumber << "_"
2801 << Loop->getHeader()->getNumber()
2802 << " Depth=" << Loop->getLoopDepth() << '\n';
2805 /// PrintChildLoopComment - Print comments about child loops within
2806 /// the loop for this basic block, with nesting.
2807 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2808 unsigned FunctionNumber) {
2809 // Add child loop information
2810 for (const MachineLoop *CL : *Loop) {
2811 OS.indent(CL->getLoopDepth()*2)
2812 << "Child Loop BB" << FunctionNumber << "_"
2813 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2815 PrintChildLoopComment(OS, CL, FunctionNumber);
2819 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2820 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2821 const MachineLoopInfo *LI,
2822 const AsmPrinter &AP) {
2823 // Add loop depth information
2824 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2827 MachineBasicBlock *Header = Loop->getHeader();
2828 assert(Header && "No header for loop");
2830 // If this block is not a loop header, just print out what is the loop header
2832 if (Header != &MBB) {
2833 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2834 Twine(AP.getFunctionNumber())+"_" +
2835 Twine(Loop->getHeader()->getNumber())+
2836 " Depth="+Twine(Loop->getLoopDepth()));
2840 // Otherwise, it is a loop header. Print out information about child and
2842 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2844 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2847 OS.indent(Loop->getLoopDepth()*2-2);
2852 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2854 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2857 void AsmPrinter::setupCodePaddingContext(const MachineBasicBlock &MBB,
2858 MCCodePaddingContext &Context) const {
2859 assert(MF != nullptr && "Machine function must be valid");
2860 Context.IsPaddingActive = !MF->hasInlineAsm() &&
2861 !MF->getFunction().optForSize() &&
2862 TM.getOptLevel() != CodeGenOpt::None;
2863 Context.IsBasicBlockReachableViaFallthrough =
2864 std::find(MBB.pred_begin(), MBB.pred_end(), MBB.getPrevNode()) !=
2866 Context.IsBasicBlockReachableViaBranch =
2867 MBB.pred_size() > 0 && !isBlockOnlyReachableByFallthrough(&MBB);
2870 /// EmitBasicBlockStart - This method prints the label for the specified
2871 /// MachineBasicBlock, an alignment (if present) and a comment describing
2872 /// it if appropriate.
2873 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2874 // End the previous funclet and start a new one.
2875 if (MBB.isEHFuncletEntry()) {
2876 for (const HandlerInfo &HI : Handlers) {
2877 HI.Handler->endFunclet();
2878 HI.Handler->beginFunclet(MBB);
2882 // Emit an alignment directive for this block, if needed.
2883 if (unsigned Align = MBB.getAlignment())
2884 EmitAlignment(Align);
2885 MCCodePaddingContext Context;
2886 setupCodePaddingContext(MBB, Context);
2887 OutStreamer->EmitCodePaddingBasicBlockStart(Context);
2889 // If the block has its address taken, emit any labels that were used to
2890 // reference the block. It is possible that there is more than one label
2891 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2892 // the references were generated.
2893 if (MBB.hasAddressTaken()) {
2894 const BasicBlock *BB = MBB.getBasicBlock();
2896 OutStreamer->AddComment("Block address taken");
2898 // MBBs can have their address taken as part of CodeGen without having
2899 // their corresponding BB's address taken in IR
2900 if (BB->hasAddressTaken())
2901 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2902 OutStreamer->EmitLabel(Sym);
2905 // Print some verbose block comments.
2907 if (const BasicBlock *BB = MBB.getBasicBlock()) {
2908 if (BB->hasName()) {
2909 BB->printAsOperand(OutStreamer->GetCommentOS(),
2910 /*PrintType=*/false, BB->getModule());
2911 OutStreamer->GetCommentOS() << '\n';
2915 assert(MLI != nullptr && "MachineLoopInfo should has been computed");
2916 emitBasicBlockLoopComments(MBB, MLI, *this);
2919 // Print the main label for the block.
2920 if (MBB.pred_empty() ||
2921 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2923 // NOTE: Want this comment at start of line, don't emit with AddComment.
2924 OutStreamer->emitRawComment(" %bb." + Twine(MBB.getNumber()) + ":",
2928 OutStreamer->EmitLabel(MBB.getSymbol());
2932 void AsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) {
2933 MCCodePaddingContext Context;
2934 setupCodePaddingContext(MBB, Context);
2935 OutStreamer->EmitCodePaddingBasicBlockEnd(Context);
2938 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2939 bool IsDefinition) const {
2940 MCSymbolAttr Attr = MCSA_Invalid;
2942 switch (Visibility) {
2944 case GlobalValue::HiddenVisibility:
2946 Attr = MAI->getHiddenVisibilityAttr();
2948 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2950 case GlobalValue::ProtectedVisibility:
2951 Attr = MAI->getProtectedVisibilityAttr();
2955 if (Attr != MCSA_Invalid)
2956 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2959 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2960 /// exactly one predecessor and the control transfer mechanism between
2961 /// the predecessor and this block is a fall-through.
2963 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2964 // If this is a landing pad, it isn't a fall through. If it has no preds,
2965 // then nothing falls through to it.
2966 if (MBB->isEHPad() || MBB->pred_empty())
2969 // If there isn't exactly one predecessor, it can't be a fall through.
2970 if (MBB->pred_size() > 1)
2973 // The predecessor has to be immediately before this block.
2974 MachineBasicBlock *Pred = *MBB->pred_begin();
2975 if (!Pred->isLayoutSuccessor(MBB))
2978 // If the block is completely empty, then it definitely does fall through.
2982 // Check the terminators in the previous blocks
2983 for (const auto &MI : Pred->terminators()) {
2984 // If it is not a simple branch, we are in a table somewhere.
2985 if (!MI.isBranch() || MI.isIndirectBranch())
2988 // If we are the operands of one of the branches, this is not a fall
2989 // through. Note that targets with delay slots will usually bundle
2990 // terminators with the delay slot instruction.
2991 for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
2994 if (OP->isMBB() && OP->getMBB() == MBB)
3002 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
3003 if (!S.usesMetadata())
3006 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
3007 gcp_map_type::iterator GCPI = GCMap.find(&S);
3008 if (GCPI != GCMap.end())
3009 return GCPI->second.get();
3011 auto Name = S.getName();
3013 for (GCMetadataPrinterRegistry::iterator
3014 I = GCMetadataPrinterRegistry::begin(),
3015 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
3016 if (Name == I->getName()) {
3017 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
3019 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
3020 return IterBool.first->second.get();
3023 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
3026 void AsmPrinter::emitStackMaps(StackMaps &SM) {
3027 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
3028 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
3029 bool NeedsDefault = false;
3030 if (MI->begin() == MI->end())
3031 // No GC strategy, use the default format.
3032 NeedsDefault = true;
3034 for (auto &I : *MI) {
3035 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
3036 if (MP->emitStackMaps(SM, *this))
3038 // The strategy doesn't have printer or doesn't emit custom stack maps.
3039 // Use the default format.
3040 NeedsDefault = true;
3044 SM.serializeToStackMapSection();
3047 /// Pin vtable to this file.
3048 AsmPrinterHandler::~AsmPrinterHandler() = default;
3050 void AsmPrinterHandler::markFunctionEnd() {}
3052 // In the binary's "xray_instr_map" section, an array of these function entries
3053 // describes each instrumentation point. When XRay patches your code, the index
3054 // into this table will be given to your handler as a patch point identifier.
3055 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out,
3056 const MCSymbol *CurrentFnSym) const {
3057 Out->EmitSymbolValue(Sled, Bytes);
3058 Out->EmitSymbolValue(CurrentFnSym, Bytes);
3059 auto Kind8 = static_cast<uint8_t>(Kind);
3060 Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
3061 Out->EmitBinaryData(
3062 StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
3063 Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Version), 1));
3064 auto Padding = (4 * Bytes) - ((2 * Bytes) + 3);
3065 assert(Padding >= 0 && "Instrumentation map entry > 4 * Word Size");
3066 Out->EmitZeros(Padding);
3069 void AsmPrinter::emitXRayTable() {
3073 auto PrevSection = OutStreamer->getCurrentSectionOnly();
3074 const Function &F = MF->getFunction();
3075 MCSection *InstMap = nullptr;
3076 MCSection *FnSledIndex = nullptr;
3077 if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) {
3078 auto Associated = dyn_cast<MCSymbolELF>(CurrentFnSym);
3079 assert(Associated != nullptr);
3080 auto Flags = ELF::SHF_WRITE | ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER;
3081 std::string GroupName;
3082 if (F.hasComdat()) {
3083 Flags |= ELF::SHF_GROUP;
3084 GroupName = F.getComdat()->getName();
3087 auto UniqueID = ++XRayFnUniqueID;
3089 OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS, Flags, 0,
3090 GroupName, UniqueID, Associated);
3092 OutContext.getELFSection("xray_fn_idx", ELF::SHT_PROGBITS, Flags, 0,
3093 GroupName, UniqueID, Associated);
3094 } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
3095 InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map", 0,
3096 SectionKind::getReadOnlyWithRel());
3097 FnSledIndex = OutContext.getMachOSection("__DATA", "xray_fn_idx", 0,
3098 SectionKind::getReadOnlyWithRel());
3100 llvm_unreachable("Unsupported target");
3103 auto WordSizeBytes = MAI->getCodePointerSize();
3105 // Now we switch to the instrumentation map section. Because this is done
3106 // per-function, we are able to create an index entry that will represent the
3107 // range of sleds associated with a function.
3108 MCSymbol *SledsStart = OutContext.createTempSymbol("xray_sleds_start", true);
3109 OutStreamer->SwitchSection(InstMap);
3110 OutStreamer->EmitLabel(SledsStart);
3111 for (const auto &Sled : Sleds)
3112 Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym);
3113 MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_sleds_end", true);
3114 OutStreamer->EmitLabel(SledsEnd);
3116 // We then emit a single entry in the index per function. We use the symbols
3117 // that bound the instrumentation map as the range for a specific function.
3118 // Each entry here will be 2 * word size aligned, as we're writing down two
3119 // pointers. This should work for both 32-bit and 64-bit platforms.
3120 OutStreamer->SwitchSection(FnSledIndex);
3121 OutStreamer->EmitCodeAlignment(2 * WordSizeBytes);
3122 OutStreamer->EmitSymbolValue(SledsStart, WordSizeBytes, false);
3123 OutStreamer->EmitSymbolValue(SledsEnd, WordSizeBytes, false);
3124 OutStreamer->SwitchSection(PrevSection);
3128 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
3129 SledKind Kind, uint8_t Version) {
3130 const Function &F = MI.getMF()->getFunction();
3131 auto Attr = F.getFnAttribute("function-instrument");
3132 bool LogArgs = F.hasFnAttribute("xray-log-args");
3133 bool AlwaysInstrument =
3134 Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always";
3135 if (Kind == SledKind::FUNCTION_ENTER && LogArgs)
3136 Kind = SledKind::LOG_ARGS_ENTER;
3137 Sleds.emplace_back(XRayFunctionEntry{Sled, CurrentFnSym, Kind,
3138 AlwaysInstrument, &F, Version});
3141 uint16_t AsmPrinter::getDwarfVersion() const {
3142 return OutStreamer->getContext().getDwarfVersion();
3145 void AsmPrinter::setDwarfVersion(uint16_t Version) {
3146 OutStreamer->getContext().setDwarfVersion(Version);