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 "AsmPrinterHandler.h"
16 #include "CodeViewDebug.h"
17 #include "DwarfDebug.h"
18 #include "DwarfException.h"
19 #include "WinException.h"
20 #include "llvm/ADT/APFloat.h"
21 #include "llvm/ADT/APInt.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/ADT/SmallPtrSet.h"
25 #include "llvm/ADT/SmallString.h"
26 #include "llvm/ADT/SmallVector.h"
27 #include "llvm/ADT/Statistic.h"
28 #include "llvm/ADT/StringRef.h"
29 #include "llvm/ADT/Triple.h"
30 #include "llvm/ADT/Twine.h"
31 #include "llvm/Analysis/ConstantFolding.h"
32 #include "llvm/Analysis/EHPersonalities.h"
33 #include "llvm/Analysis/ObjectUtils.h"
34 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
35 #include "llvm/BinaryFormat/Dwarf.h"
36 #include "llvm/BinaryFormat/ELF.h"
37 #include "llvm/CodeGen/GCMetadata.h"
38 #include "llvm/CodeGen/GCMetadataPrinter.h"
39 #include "llvm/CodeGen/GCStrategy.h"
40 #include "llvm/CodeGen/MachineBasicBlock.h"
41 #include "llvm/CodeGen/MachineConstantPool.h"
42 #include "llvm/CodeGen/MachineFrameInfo.h"
43 #include "llvm/CodeGen/MachineFunction.h"
44 #include "llvm/CodeGen/MachineFunctionPass.h"
45 #include "llvm/CodeGen/MachineInstr.h"
46 #include "llvm/CodeGen/MachineInstrBundle.h"
47 #include "llvm/CodeGen/MachineJumpTableInfo.h"
48 #include "llvm/CodeGen/MachineLoopInfo.h"
49 #include "llvm/CodeGen/MachineMemOperand.h"
50 #include "llvm/CodeGen/MachineModuleInfo.h"
51 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
52 #include "llvm/CodeGen/MachineOperand.h"
53 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
54 #include "llvm/CodeGen/TargetFrameLowering.h"
55 #include "llvm/CodeGen/TargetInstrInfo.h"
56 #include "llvm/CodeGen/TargetLowering.h"
57 #include "llvm/CodeGen/TargetLoweringObjectFile.h"
58 #include "llvm/CodeGen/TargetOpcodes.h"
59 #include "llvm/CodeGen/TargetRegisterInfo.h"
60 #include "llvm/CodeGen/TargetSubtargetInfo.h"
61 #include "llvm/IR/BasicBlock.h"
62 #include "llvm/IR/Comdat.h"
63 #include "llvm/IR/Constant.h"
64 #include "llvm/IR/Constants.h"
65 #include "llvm/IR/DataLayout.h"
66 #include "llvm/IR/DebugInfoMetadata.h"
67 #include "llvm/IR/DerivedTypes.h"
68 #include "llvm/IR/Function.h"
69 #include "llvm/IR/GlobalAlias.h"
70 #include "llvm/IR/GlobalIFunc.h"
71 #include "llvm/IR/GlobalIndirectSymbol.h"
72 #include "llvm/IR/GlobalObject.h"
73 #include "llvm/IR/GlobalValue.h"
74 #include "llvm/IR/GlobalVariable.h"
75 #include "llvm/IR/Instruction.h"
76 #include "llvm/IR/Mangler.h"
77 #include "llvm/IR/Metadata.h"
78 #include "llvm/IR/Module.h"
79 #include "llvm/IR/Operator.h"
80 #include "llvm/IR/Type.h"
81 #include "llvm/IR/Value.h"
82 #include "llvm/MC/MCAsmInfo.h"
83 #include "llvm/MC/MCCodePadder.h"
84 #include "llvm/MC/MCContext.h"
85 #include "llvm/MC/MCDirectives.h"
86 #include "llvm/MC/MCDwarf.h"
87 #include "llvm/MC/MCExpr.h"
88 #include "llvm/MC/MCInst.h"
89 #include "llvm/MC/MCSection.h"
90 #include "llvm/MC/MCSectionELF.h"
91 #include "llvm/MC/MCSectionMachO.h"
92 #include "llvm/MC/MCStreamer.h"
93 #include "llvm/MC/MCSubtargetInfo.h"
94 #include "llvm/MC/MCSymbol.h"
95 #include "llvm/MC/MCSymbolELF.h"
96 #include "llvm/MC/MCTargetOptions.h"
97 #include "llvm/MC/MCValue.h"
98 #include "llvm/MC/SectionKind.h"
99 #include "llvm/Pass.h"
100 #include "llvm/Support/Casting.h"
101 #include "llvm/Support/CommandLine.h"
102 #include "llvm/Support/Compiler.h"
103 #include "llvm/Support/ErrorHandling.h"
104 #include "llvm/Support/Format.h"
105 #include "llvm/Support/MathExtras.h"
106 #include "llvm/Support/Path.h"
107 #include "llvm/Support/TargetRegistry.h"
108 #include "llvm/Support/Timer.h"
109 #include "llvm/Support/raw_ostream.h"
110 #include "llvm/Target/TargetMachine.h"
111 #include "llvm/Target/TargetOptions.h"
123 using namespace llvm;
125 #define DEBUG_TYPE "asm-printer"
127 static const char *const DWARFGroupName = "dwarf";
128 static const char *const DWARFGroupDescription = "DWARF Emission";
129 static const char *const DbgTimerName = "emit";
130 static const char *const DbgTimerDescription = "Debug Info Emission";
131 static const char *const EHTimerName = "write_exception";
132 static const char *const EHTimerDescription = "DWARF Exception Writer";
133 static const char *const CodeViewLineTablesGroupName = "linetables";
134 static const char *const CodeViewLineTablesGroupDescription =
135 "CodeView Line Tables";
137 STATISTIC(EmittedInsts, "Number of machine instrs printed");
140 PrintSchedule("print-schedule", cl::Hidden, cl::init(false),
141 cl::desc("Print 'sched: [latency:throughput]' in .s output"));
143 char AsmPrinter::ID = 0;
145 using gcp_map_type = DenseMap<GCStrategy *, std::unique_ptr<GCMetadataPrinter>>;
147 static gcp_map_type &getGCMap(void *&P) {
149 P = new gcp_map_type();
150 return *(gcp_map_type*)P;
153 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
154 /// value in log2 form. This rounds up to the preferred alignment if possible
156 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
157 unsigned InBits = 0) {
158 unsigned NumBits = 0;
159 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
160 NumBits = DL.getPreferredAlignmentLog(GVar);
162 // If InBits is specified, round it to it.
163 if (InBits > NumBits)
166 // If the GV has a specified alignment, take it into account.
167 if (GV->getAlignment() == 0)
170 unsigned GVAlign = Log2_32(GV->getAlignment());
172 // If the GVAlign is larger than NumBits, or if we are required to obey
173 // NumBits because the GV has an assigned section, obey it.
174 if (GVAlign > NumBits || GV->hasSection())
179 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
180 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
181 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) {
182 VerboseAsm = OutStreamer->isVerboseAsm();
185 AsmPrinter::~AsmPrinter() {
186 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
188 if (GCMetadataPrinters) {
189 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
192 GCMetadataPrinters = nullptr;
196 bool AsmPrinter::isPositionIndependent() const {
197 return TM.isPositionIndependent();
200 /// getFunctionNumber - Return a unique ID for the current function.
201 unsigned AsmPrinter::getFunctionNumber() const {
202 return MF->getFunctionNumber();
205 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
206 return *TM.getObjFileLowering();
209 const DataLayout &AsmPrinter::getDataLayout() const {
210 return MMI->getModule()->getDataLayout();
213 // Do not use the cached DataLayout because some client use it without a Module
214 // (llvm-dsymutil, llvm-dwarfdump).
215 unsigned AsmPrinter::getPointerSize() const { return TM.getPointerSize(); }
217 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
218 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
219 return MF->getSubtarget<MCSubtargetInfo>();
222 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
223 S.EmitInstruction(Inst, getSubtargetInfo());
226 /// getCurrentSection() - Return the current section we are emitting to.
227 const MCSection *AsmPrinter::getCurrentSection() const {
228 return OutStreamer->getCurrentSectionOnly();
231 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
232 AU.setPreservesAll();
233 MachineFunctionPass::getAnalysisUsage(AU);
234 AU.addRequired<MachineModuleInfo>();
235 AU.addRequired<MachineOptimizationRemarkEmitterPass>();
236 AU.addRequired<GCModuleInfo>();
237 AU.addRequired<MachineLoopInfo>();
240 bool AsmPrinter::doInitialization(Module &M) {
241 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
243 // Initialize TargetLoweringObjectFile.
244 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
245 .Initialize(OutContext, TM);
247 OutStreamer->InitSections(false);
249 // Emit the version-min deplyment target directive if needed.
251 // FIXME: If we end up with a collection of these sorts of Darwin-specific
252 // or ELF-specific things, it may make sense to have a platform helper class
253 // that will work with the target helper class. For now keep it here, as the
254 // alternative is duplicated code in each of the target asm printers that
255 // use the directive, where it would need the same conditionalization
257 const Triple &Target = TM.getTargetTriple();
258 OutStreamer->EmitVersionForTarget(Target);
260 // Allow the target to emit any magic that it wants at the start of the file.
261 EmitStartOfAsmFile(M);
263 // Very minimal debug info. It is ignored if we emit actual debug info. If we
264 // don't, this at least helps the user find where a global came from.
265 if (MAI->hasSingleParameterDotFile()) {
267 OutStreamer->EmitFileDirective(
268 llvm::sys::path::filename(M.getSourceFileName()));
271 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
272 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
274 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
275 MP->beginAssembly(M, *MI, *this);
277 // Emit module-level inline asm if it exists.
278 if (!M.getModuleInlineAsm().empty()) {
279 // We're at the module level. Construct MCSubtarget from the default CPU
280 // and target triple.
281 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
282 TM.getTargetTriple().str(), TM.getTargetCPU(),
283 TM.getTargetFeatureString()));
284 OutStreamer->AddComment("Start of file scope inline assembly");
285 OutStreamer->AddBlankLine();
286 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
287 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
288 OutStreamer->AddComment("End of file scope inline assembly");
289 OutStreamer->AddBlankLine();
292 if (MAI->doesSupportDebugInformation()) {
293 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
294 if (EmitCodeView && (TM.getTargetTriple().isKnownWindowsMSVCEnvironment() ||
295 TM.getTargetTriple().isWindowsItaniumEnvironment())) {
296 Handlers.push_back(HandlerInfo(new CodeViewDebug(this),
297 DbgTimerName, DbgTimerDescription,
298 CodeViewLineTablesGroupName,
299 CodeViewLineTablesGroupDescription));
301 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
302 DD = new DwarfDebug(this, &M);
304 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DbgTimerDescription,
305 DWARFGroupName, DWARFGroupDescription));
309 switch (MAI->getExceptionHandlingType()) {
310 case ExceptionHandling::SjLj:
311 case ExceptionHandling::DwarfCFI:
312 case ExceptionHandling::ARM:
313 isCFIMoveForDebugging = true;
314 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
316 for (auto &F: M.getFunctionList()) {
317 // If the module contains any function with unwind data,
318 // .eh_frame has to be emitted.
319 // Ignore functions that won't get emitted.
320 if (!F.isDeclarationForLinker() && F.needsUnwindTableEntry()) {
321 isCFIMoveForDebugging = false;
327 isCFIMoveForDebugging = false;
331 EHStreamer *ES = nullptr;
332 switch (MAI->getExceptionHandlingType()) {
333 case ExceptionHandling::None:
335 case ExceptionHandling::SjLj:
336 case ExceptionHandling::DwarfCFI:
337 ES = new DwarfCFIException(this);
339 case ExceptionHandling::ARM:
340 ES = new ARMException(this);
342 case ExceptionHandling::WinEH:
343 switch (MAI->getWinEHEncodingType()) {
344 default: llvm_unreachable("unsupported unwinding information encoding");
345 case WinEH::EncodingType::Invalid:
347 case WinEH::EncodingType::X86:
348 case WinEH::EncodingType::Itanium:
349 ES = new WinException(this);
355 Handlers.push_back(HandlerInfo(ES, EHTimerName, EHTimerDescription,
356 DWARFGroupName, DWARFGroupDescription));
360 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
361 if (!MAI.hasWeakDefCanBeHiddenDirective())
364 return canBeOmittedFromSymbolTable(GV);
367 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
368 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
370 case GlobalValue::CommonLinkage:
371 case GlobalValue::LinkOnceAnyLinkage:
372 case GlobalValue::LinkOnceODRLinkage:
373 case GlobalValue::WeakAnyLinkage:
374 case GlobalValue::WeakODRLinkage:
375 if (MAI->hasWeakDefDirective()) {
377 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
379 if (!canBeHidden(GV, *MAI))
380 // .weak_definition _foo
381 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
383 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
384 } else if (MAI->hasLinkOnceDirective()) {
386 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
387 //NOTE: linkonce is handled by the section the symbol was assigned to.
390 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
393 case GlobalValue::ExternalLinkage:
394 // If external, declare as a global symbol: .globl _foo
395 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
397 case GlobalValue::PrivateLinkage:
398 case GlobalValue::InternalLinkage:
400 case GlobalValue::AppendingLinkage:
401 case GlobalValue::AvailableExternallyLinkage:
402 case GlobalValue::ExternalWeakLinkage:
403 llvm_unreachable("Should never emit this");
405 llvm_unreachable("Unknown linkage type!");
408 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
409 const GlobalValue *GV) const {
410 TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
413 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
414 return TM.getSymbol(GV);
417 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
418 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
419 bool IsEmuTLSVar = TM.Options.EmulatedTLS && GV->isThreadLocal();
420 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
421 "No emulated TLS variables in the common section");
423 // Never emit TLS variable xyz in emulated TLS model.
424 // The initialization value is in __emutls_t.xyz instead of xyz.
428 if (GV->hasInitializer()) {
429 // Check to see if this is a special global used by LLVM, if so, emit it.
430 if (EmitSpecialLLVMGlobal(GV))
433 // Skip the emission of global equivalents. The symbol can be emitted later
434 // on by emitGlobalGOTEquivs in case it turns out to be needed.
435 if (GlobalGOTEquivs.count(getSymbol(GV)))
439 // When printing the control variable __emutls_v.*,
440 // we don't need to print the original TLS variable name.
441 GV->printAsOperand(OutStreamer->GetCommentOS(),
442 /*PrintType=*/false, GV->getParent());
443 OutStreamer->GetCommentOS() << '\n';
447 MCSymbol *GVSym = getSymbol(GV);
448 MCSymbol *EmittedSym = GVSym;
450 // getOrCreateEmuTLSControlSym only creates the symbol with name and default
452 // GV's or GVSym's attributes will be used for the EmittedSym.
453 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
455 if (!GV->hasInitializer()) // External globals require no extra code.
458 GVSym->redefineIfPossible();
459 if (GVSym->isDefined() || GVSym->isVariable())
460 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
461 "' is already defined");
463 if (MAI->hasDotTypeDotSizeDirective())
464 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
466 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
468 const DataLayout &DL = GV->getParent()->getDataLayout();
469 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
471 // If the alignment is specified, we *must* obey it. Overaligning a global
472 // with a specified alignment is a prompt way to break globals emitted to
473 // sections and expected to be contiguous (e.g. ObjC metadata).
474 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
476 for (const HandlerInfo &HI : Handlers) {
477 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
478 HI.TimerGroupName, HI.TimerGroupDescription,
479 TimePassesIsEnabled);
480 HI.Handler->setSymbolSize(GVSym, Size);
483 // Handle common symbols
484 if (GVKind.isCommon()) {
485 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
486 unsigned Align = 1 << AlignLog;
487 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
491 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
495 // Determine to which section this global should be emitted.
496 MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
498 // If we have a bss global going to a section that supports the
499 // zerofill directive, do so here.
500 if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
501 TheSection->isVirtualSection()) {
503 Size = 1; // zerofill of 0 bytes is undefined.
504 unsigned Align = 1 << AlignLog;
505 EmitLinkage(GV, GVSym);
506 // .zerofill __DATA, __bss, _foo, 400, 5
507 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
511 // If this is a BSS local symbol and we are emitting in the BSS
512 // section use .lcomm/.comm directive.
513 if (GVKind.isBSSLocal() &&
514 getObjFileLowering().getBSSSection() == TheSection) {
516 Size = 1; // .comm Foo, 0 is undefined, avoid it.
517 unsigned Align = 1 << AlignLog;
519 // Use .lcomm only if it supports user-specified alignment.
520 // Otherwise, while it would still be correct to use .lcomm in some
521 // cases (e.g. when Align == 1), the external assembler might enfore
522 // some -unknown- default alignment behavior, which could cause
523 // spurious differences between external and integrated assembler.
524 // Prefer to simply fall back to .local / .comm in this case.
525 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
527 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
531 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
535 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
537 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
541 // Handle thread local data for mach-o which requires us to output an
542 // additional structure of data and mangle the original symbol so that we
543 // can reference it later.
545 // TODO: This should become an "emit thread local global" method on TLOF.
546 // All of this macho specific stuff should be sunk down into TLOFMachO and
547 // stuff like "TLSExtraDataSection" should no longer be part of the parent
548 // TLOF class. This will also make it more obvious that stuff like
549 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
551 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
552 // Emit the .tbss symbol
554 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
556 if (GVKind.isThreadBSS()) {
557 TheSection = getObjFileLowering().getTLSBSSSection();
558 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
559 } else if (GVKind.isThreadData()) {
560 OutStreamer->SwitchSection(TheSection);
562 EmitAlignment(AlignLog, GV);
563 OutStreamer->EmitLabel(MangSym);
565 EmitGlobalConstant(GV->getParent()->getDataLayout(),
566 GV->getInitializer());
569 OutStreamer->AddBlankLine();
571 // Emit the variable struct for the runtime.
572 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
574 OutStreamer->SwitchSection(TLVSect);
575 // Emit the linkage here.
576 EmitLinkage(GV, GVSym);
577 OutStreamer->EmitLabel(GVSym);
579 // Three pointers in size:
580 // - __tlv_bootstrap - used to make sure support exists
581 // - spare pointer, used when mapped by the runtime
582 // - pointer to mangled symbol above with initializer
583 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
584 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
586 OutStreamer->EmitIntValue(0, PtrSize);
587 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
589 OutStreamer->AddBlankLine();
593 MCSymbol *EmittedInitSym = GVSym;
595 OutStreamer->SwitchSection(TheSection);
597 EmitLinkage(GV, EmittedInitSym);
598 EmitAlignment(AlignLog, GV);
600 OutStreamer->EmitLabel(EmittedInitSym);
602 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
604 if (MAI->hasDotTypeDotSizeDirective())
606 OutStreamer->emitELFSize(EmittedInitSym,
607 MCConstantExpr::create(Size, OutContext));
609 OutStreamer->AddBlankLine();
612 /// Emit the directive and value for debug thread local expression
614 /// \p Value - The value to emit.
615 /// \p Size - The size of the integer (in bytes) to emit.
616 void AsmPrinter::EmitDebugThreadLocal(const MCExpr *Value,
617 unsigned Size) const {
618 OutStreamer->EmitValue(Value, Size);
621 /// EmitFunctionHeader - This method emits the header for the current
623 void AsmPrinter::EmitFunctionHeader() {
624 const Function &F = MF->getFunction();
627 OutStreamer->GetCommentOS()
628 << "-- Begin function "
629 << GlobalValue::dropLLVMManglingEscape(F.getName()) << '\n';
631 // Print out constants referenced by the function
634 // Print the 'header' of function.
635 OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(&F, TM));
636 EmitVisibility(CurrentFnSym, F.getVisibility());
638 EmitLinkage(&F, CurrentFnSym);
639 if (MAI->hasFunctionAlignment())
640 EmitAlignment(MF->getAlignment(), &F);
642 if (MAI->hasDotTypeDotSizeDirective())
643 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
646 F.printAsOperand(OutStreamer->GetCommentOS(),
647 /*PrintType=*/false, F.getParent());
648 OutStreamer->GetCommentOS() << '\n';
651 // Emit the prefix data.
652 if (F.hasPrefixData()) {
653 if (MAI->hasSubsectionsViaSymbols()) {
654 // Preserving prefix data on platforms which use subsections-via-symbols
655 // is a bit tricky. Here we introduce a symbol for the prefix data
656 // and use the .alt_entry attribute to mark the function's real entry point
657 // as an alternative entry point to the prefix-data symbol.
658 MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
659 OutStreamer->EmitLabel(PrefixSym);
661 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
663 // Emit an .alt_entry directive for the actual function symbol.
664 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
666 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
670 // Emit the CurrentFnSym. This is a virtual function to allow targets to
671 // do their wild and crazy things as required.
672 EmitFunctionEntryLabel();
674 // If the function had address-taken blocks that got deleted, then we have
675 // references to the dangling symbols. Emit them at the start of the function
676 // so that we don't get references to undefined symbols.
677 std::vector<MCSymbol*> DeadBlockSyms;
678 MMI->takeDeletedSymbolsForFunction(&F, DeadBlockSyms);
679 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
680 OutStreamer->AddComment("Address taken block that was later removed");
681 OutStreamer->EmitLabel(DeadBlockSyms[i]);
684 if (CurrentFnBegin) {
685 if (MAI->useAssignmentForEHBegin()) {
686 MCSymbol *CurPos = OutContext.createTempSymbol();
687 OutStreamer->EmitLabel(CurPos);
688 OutStreamer->EmitAssignment(CurrentFnBegin,
689 MCSymbolRefExpr::create(CurPos, OutContext));
691 OutStreamer->EmitLabel(CurrentFnBegin);
695 // Emit pre-function debug and/or EH information.
696 for (const HandlerInfo &HI : Handlers) {
697 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
698 HI.TimerGroupDescription, TimePassesIsEnabled);
699 HI.Handler->beginFunction(MF);
702 // Emit the prologue data.
703 if (F.hasPrologueData())
704 EmitGlobalConstant(F.getParent()->getDataLayout(), F.getPrologueData());
707 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
708 /// function. This can be overridden by targets as required to do custom stuff.
709 void AsmPrinter::EmitFunctionEntryLabel() {
710 CurrentFnSym->redefineIfPossible();
712 // The function label could have already been emitted if two symbols end up
713 // conflicting due to asm renaming. Detect this and emit an error.
714 if (CurrentFnSym->isVariable())
715 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
716 "' is a protected alias");
717 if (CurrentFnSym->isDefined())
718 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
719 "' label emitted multiple times to assembly file");
721 return OutStreamer->EmitLabel(CurrentFnSym);
724 /// emitComments - Pretty-print comments for instructions.
725 /// It returns true iff the sched comment was emitted.
726 /// Otherwise it returns false.
727 static bool emitComments(const MachineInstr &MI, raw_ostream &CommentOS,
729 const MachineFunction *MF = MI.getMF();
730 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
732 // Check for spills and reloads
735 const MachineFrameInfo &MFI = MF->getFrameInfo();
736 bool Commented = false;
738 // We assume a single instruction only has a spill or reload, not
740 const MachineMemOperand *MMO;
741 if (TII->isLoadFromStackSlotPostFE(MI, FI)) {
742 if (MFI.isSpillSlotObjectIndex(FI)) {
743 MMO = *MI.memoperands_begin();
744 CommentOS << MMO->getSize() << "-byte Reload";
747 } else if (TII->hasLoadFromStackSlot(MI, MMO, FI)) {
748 if (MFI.isSpillSlotObjectIndex(FI)) {
749 CommentOS << MMO->getSize() << "-byte Folded Reload";
752 } else if (TII->isStoreToStackSlotPostFE(MI, FI)) {
753 if (MFI.isSpillSlotObjectIndex(FI)) {
754 MMO = *MI.memoperands_begin();
755 CommentOS << MMO->getSize() << "-byte Spill";
758 } else if (TII->hasStoreToStackSlot(MI, MMO, FI)) {
759 if (MFI.isSpillSlotObjectIndex(FI)) {
760 CommentOS << MMO->getSize() << "-byte Folded Spill";
765 // Check for spill-induced copies
766 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) {
768 CommentOS << " Reload Reuse";
772 if (AP->EnablePrintSchedInfo) {
773 // If any comment was added above and we need sched info comment then add
774 // this new comment just after the above comment w/o "\n" between them.
775 CommentOS << " " << MF->getSubtarget().getSchedInfoStr(MI) << "\n";
783 /// emitImplicitDef - This method emits the specified machine instruction
784 /// that is an implicit def.
785 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
786 unsigned RegNo = MI->getOperand(0).getReg();
788 SmallString<128> Str;
789 raw_svector_ostream OS(Str);
790 OS << "implicit-def: "
791 << printReg(RegNo, MF->getSubtarget().getRegisterInfo());
793 OutStreamer->AddComment(OS.str());
794 OutStreamer->AddBlankLine();
797 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
799 raw_string_ostream OS(Str);
801 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
802 const MachineOperand &Op = MI->getOperand(i);
803 assert(Op.isReg() && "KILL instruction must have only register operands");
804 OS << ' ' << (Op.isDef() ? "def " : "killed ")
805 << printReg(Op.getReg(), AP.MF->getSubtarget().getRegisterInfo());
807 AP.OutStreamer->AddComment(OS.str());
808 AP.OutStreamer->AddBlankLine();
811 /// emitDebugValueComment - This method handles the target-independent form
812 /// of DBG_VALUE, returning true if it was able to do so. A false return
813 /// means the target will need to handle MI in EmitInstruction.
814 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
815 // This code handles only the 4-operand target-independent form.
816 if (MI->getNumOperands() != 4)
819 SmallString<128> Str;
820 raw_svector_ostream OS(Str);
821 OS << "DEBUG_VALUE: ";
823 const DILocalVariable *V = MI->getDebugVariable();
824 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
825 StringRef Name = SP->getName();
832 // The second operand is only an offset if it's an immediate.
833 bool MemLoc = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
834 int64_t Offset = MemLoc ? MI->getOperand(1).getImm() : 0;
835 const DIExpression *Expr = MI->getDebugExpression();
836 if (Expr->getNumElements()) {
838 bool NeedSep = false;
839 for (auto Op : Expr->expr_ops()) {
844 OS << dwarf::OperationEncodingString(Op.getOp());
845 for (unsigned I = 0; I < Op.getNumArgs(); ++I)
846 OS << ' ' << Op.getArg(I);
851 // Register or immediate value. Register 0 means undef.
852 if (MI->getOperand(0).isFPImm()) {
853 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
854 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
855 OS << (double)APF.convertToFloat();
856 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
857 OS << APF.convertToDouble();
859 // There is no good way to print long double. Convert a copy to
860 // double. Ah well, it's only a comment.
862 APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
864 OS << "(long double) " << APF.convertToDouble();
866 } else if (MI->getOperand(0).isImm()) {
867 OS << MI->getOperand(0).getImm();
868 } else if (MI->getOperand(0).isCImm()) {
869 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
872 if (MI->getOperand(0).isReg()) {
873 Reg = MI->getOperand(0).getReg();
875 assert(MI->getOperand(0).isFI() && "Unknown operand type");
876 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
877 Offset += TFI->getFrameIndexReference(*AP.MF,
878 MI->getOperand(0).getIndex(), Reg);
882 // Suppress offset, it is not meaningful here.
884 // NOTE: Want this comment at start of line, don't emit with AddComment.
885 AP.OutStreamer->emitRawComment(OS.str());
890 OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
894 OS << '+' << Offset << ']';
896 // NOTE: Want this comment at start of line, don't emit with AddComment.
897 AP.OutStreamer->emitRawComment(OS.str());
901 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() const {
902 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
903 MF->getFunction().needsUnwindTableEntry())
906 if (MMI->hasDebugInfo())
912 bool AsmPrinter::needsSEHMoves() {
913 return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry();
916 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
917 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
918 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
919 ExceptionHandlingType != ExceptionHandling::ARM)
922 if (needsCFIMoves() == CFI_M_None)
925 // If there is no "real" instruction following this CFI instruction, skip
926 // emitting it; it would be beyond the end of the function's FDE range.
927 auto *MBB = MI.getParent();
928 auto I = std::next(MI.getIterator());
929 while (I != MBB->end() && I->isTransient())
931 if (I == MBB->instr_end() &&
932 MBB->getReverseIterator() == MBB->getParent()->rbegin())
935 const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions();
936 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
937 const MCCFIInstruction &CFI = Instrs[CFIIndex];
938 emitCFIInstruction(CFI);
941 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
942 // The operands are the MCSymbol and the frame offset of the allocation.
943 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
944 int FrameOffset = MI.getOperand(1).getImm();
946 // Emit a symbol assignment.
947 OutStreamer->EmitAssignment(FrameAllocSym,
948 MCConstantExpr::create(FrameOffset, OutContext));
951 void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) {
952 if (!MF.getTarget().Options.EmitStackSizeSection)
955 MCSection *StackSizeSection = getObjFileLowering().getStackSizesSection();
956 if (!StackSizeSection)
959 const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
960 // Don't emit functions with dynamic stack allocations.
961 if (FrameInfo.hasVarSizedObjects())
964 OutStreamer->PushSection();
965 OutStreamer->SwitchSection(StackSizeSection);
967 const MCSymbol *FunctionSymbol = getSymbol(&MF.getFunction());
968 uint64_t StackSize = FrameInfo.getStackSize();
969 OutStreamer->EmitValue(MCSymbolRefExpr::create(FunctionSymbol, OutContext),
971 OutStreamer->EmitULEB128IntValue(StackSize);
973 OutStreamer->PopSection();
976 static bool needFuncLabelsForEHOrDebugInfo(const MachineFunction &MF,
977 MachineModuleInfo *MMI) {
978 if (!MF.getLandingPads().empty() || MF.hasEHFunclets() || MMI->hasDebugInfo())
981 // We might emit an EH table that uses function begin and end labels even if
982 // we don't have any landingpads.
983 if (!MF.getFunction().hasPersonalityFn())
985 return !isNoOpWithoutInvoke(
986 classifyEHPersonality(MF.getFunction().getPersonalityFn()));
989 /// EmitFunctionBody - This method emits the body and trailer for a
991 void AsmPrinter::EmitFunctionBody() {
992 EmitFunctionHeader();
994 // Emit target-specific gunk before the function body.
995 EmitFunctionBodyStart();
997 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
999 // Print out code for the function.
1000 bool HasAnyRealCode = false;
1001 int NumInstsInFunction = 0;
1002 for (auto &MBB : *MF) {
1003 // Print a label for the basic block.
1004 EmitBasicBlockStart(MBB);
1005 for (auto &MI : MBB) {
1006 // Print the assembly for the instruction.
1007 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
1008 !MI.isDebugValue()) {
1009 HasAnyRealCode = true;
1010 ++NumInstsInFunction;
1013 if (ShouldPrintDebugScopes) {
1014 for (const HandlerInfo &HI : Handlers) {
1015 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1016 HI.TimerGroupName, HI.TimerGroupDescription,
1017 TimePassesIsEnabled);
1018 HI.Handler->beginInstruction(&MI);
1022 if (isVerbose() && emitComments(MI, OutStreamer->GetCommentOS(), this)) {
1023 MachineInstr *MIP = const_cast<MachineInstr *>(&MI);
1024 MIP->setAsmPrinterFlag(MachineInstr::NoSchedComment);
1027 switch (MI.getOpcode()) {
1028 case TargetOpcode::CFI_INSTRUCTION:
1029 emitCFIInstruction(MI);
1031 case TargetOpcode::LOCAL_ESCAPE:
1034 case TargetOpcode::EH_LABEL:
1035 case TargetOpcode::GC_LABEL:
1036 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
1038 case TargetOpcode::INLINEASM:
1041 case TargetOpcode::DBG_VALUE:
1043 if (!emitDebugValueComment(&MI, *this))
1044 EmitInstruction(&MI);
1047 case TargetOpcode::IMPLICIT_DEF:
1048 if (isVerbose()) emitImplicitDef(&MI);
1050 case TargetOpcode::KILL:
1051 if (isVerbose()) emitKill(&MI, *this);
1054 EmitInstruction(&MI);
1058 if (ShouldPrintDebugScopes) {
1059 for (const HandlerInfo &HI : Handlers) {
1060 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1061 HI.TimerGroupName, HI.TimerGroupDescription,
1062 TimePassesIsEnabled);
1063 HI.Handler->endInstruction();
1068 EmitBasicBlockEnd(MBB);
1071 EmittedInsts += NumInstsInFunction;
1072 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
1073 MF->getFunction().getSubprogram(),
1075 R << ore::NV("NumInstructions", NumInstsInFunction)
1076 << " instructions in function";
1079 // If the function is empty and the object file uses .subsections_via_symbols,
1080 // then we need to emit *something* to the function body to prevent the
1081 // labels from collapsing together. Just emit a noop.
1082 // Similarly, don't emit empty functions on Windows either. It can lead to
1083 // duplicate entries (two functions with the same RVA) in the Guard CF Table
1084 // after linking, causing the kernel not to load the binary:
1085 // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
1086 // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
1087 const Triple &TT = TM.getTargetTriple();
1088 if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() ||
1089 (TT.isOSWindows() && TT.isOSBinFormatCOFF()))) {
1091 MF->getSubtarget().getInstrInfo()->getNoop(Noop);
1093 // Targets can opt-out of emitting the noop here by leaving the opcode
1095 if (Noop.getOpcode()) {
1096 OutStreamer->AddComment("avoids zero-length function");
1097 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
1101 const Function &F = MF->getFunction();
1102 for (const auto &BB : F) {
1103 if (!BB.hasAddressTaken())
1105 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
1106 if (Sym->isDefined())
1108 OutStreamer->AddComment("Address of block that was removed by CodeGen");
1109 OutStreamer->EmitLabel(Sym);
1112 // Emit target-specific gunk after the function body.
1113 EmitFunctionBodyEnd();
1115 if (needFuncLabelsForEHOrDebugInfo(*MF, MMI) ||
1116 MAI->hasDotTypeDotSizeDirective()) {
1117 // Create a symbol for the end of function.
1118 CurrentFnEnd = createTempSymbol("func_end");
1119 OutStreamer->EmitLabel(CurrentFnEnd);
1122 // If the target wants a .size directive for the size of the function, emit
1124 if (MAI->hasDotTypeDotSizeDirective()) {
1125 // We can get the size as difference between the function label and the
1127 const MCExpr *SizeExp = MCBinaryExpr::createSub(
1128 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1129 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1130 OutStreamer->emitELFSize(CurrentFnSym, SizeExp);
1133 for (const HandlerInfo &HI : Handlers) {
1134 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1135 HI.TimerGroupDescription, TimePassesIsEnabled);
1136 HI.Handler->markFunctionEnd();
1139 // Print out jump tables referenced by the function.
1140 EmitJumpTableInfo();
1142 // Emit post-function debug and/or EH information.
1143 for (const HandlerInfo &HI : Handlers) {
1144 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1145 HI.TimerGroupDescription, TimePassesIsEnabled);
1146 HI.Handler->endFunction(MF);
1149 // Emit section containing stack size metadata.
1150 emitStackSizeSection(*MF);
1153 OutStreamer->GetCommentOS() << "-- End function\n";
1155 OutStreamer->AddBlankLine();
1158 /// \brief Compute the number of Global Variables that uses a Constant.
1159 static unsigned getNumGlobalVariableUses(const Constant *C) {
1163 if (isa<GlobalVariable>(C))
1166 unsigned NumUses = 0;
1167 for (auto *CU : C->users())
1168 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1173 /// \brief Only consider global GOT equivalents if at least one user is a
1174 /// cstexpr inside an initializer of another global variables. Also, don't
1175 /// handle cstexpr inside instructions. During global variable emission,
1176 /// candidates are skipped and are emitted later in case at least one cstexpr
1177 /// isn't replaced by a PC relative GOT entry access.
1178 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1179 unsigned &NumGOTEquivUsers) {
1180 // Global GOT equivalents are unnamed private globals with a constant
1181 // pointer initializer to another global symbol. They must point to a
1182 // GlobalVariable or Function, i.e., as GlobalValue.
1183 if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
1184 !GV->isConstant() || !GV->isDiscardableIfUnused() ||
1185 !dyn_cast<GlobalValue>(GV->getOperand(0)))
1188 // To be a got equivalent, at least one of its users need to be a constant
1189 // expression used by another global variable.
1190 for (auto *U : GV->users())
1191 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1193 return NumGOTEquivUsers > 0;
1196 /// \brief Unnamed constant global variables solely contaning a pointer to
1197 /// another globals variable is equivalent to a GOT table entry; it contains the
1198 /// the address of another symbol. Optimize it and replace accesses to these
1199 /// "GOT equivalents" by using the GOT entry for the final global instead.
1200 /// Compute GOT equivalent candidates among all global variables to avoid
1201 /// emitting them if possible later on, after it use is replaced by a GOT entry
1203 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1204 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1207 for (const auto &G : M.globals()) {
1208 unsigned NumGOTEquivUsers = 0;
1209 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1212 const MCSymbol *GOTEquivSym = getSymbol(&G);
1213 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1217 /// \brief Constant expressions using GOT equivalent globals may not be eligible
1218 /// for PC relative GOT entry conversion, in such cases we need to emit such
1219 /// globals we previously omitted in EmitGlobalVariable.
1220 void AsmPrinter::emitGlobalGOTEquivs() {
1221 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1224 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1225 for (auto &I : GlobalGOTEquivs) {
1226 const GlobalVariable *GV = I.second.first;
1227 unsigned Cnt = I.second.second;
1229 FailedCandidates.push_back(GV);
1231 GlobalGOTEquivs.clear();
1233 for (auto *GV : FailedCandidates)
1234 EmitGlobalVariable(GV);
1237 void AsmPrinter::emitGlobalIndirectSymbol(Module &M,
1238 const GlobalIndirectSymbol& GIS) {
1239 MCSymbol *Name = getSymbol(&GIS);
1241 if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective())
1242 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1243 else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage())
1244 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1246 assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage");
1248 // Set the symbol type to function if the alias has a function type.
1249 // This affects codegen when the aliasee is not a function.
1250 if (GIS.getType()->getPointerElementType()->isFunctionTy()) {
1251 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
1252 if (isa<GlobalIFunc>(GIS))
1253 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
1256 EmitVisibility(Name, GIS.getVisibility());
1258 const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol());
1260 if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
1261 OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry);
1263 // Emit the directives as assignments aka .set:
1264 OutStreamer->EmitAssignment(Name, Expr);
1266 if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) {
1267 // If the aliasee does not correspond to a symbol in the output, i.e. the
1268 // alias is not of an object or the aliased object is private, then set the
1269 // size of the alias symbol from the type of the alias. We don't do this in
1270 // other situations as the alias and aliasee having differing types but same
1271 // size may be intentional.
1272 const GlobalObject *BaseObject = GA->getBaseObject();
1273 if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() &&
1274 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1275 const DataLayout &DL = M.getDataLayout();
1276 uint64_t Size = DL.getTypeAllocSize(GA->getValueType());
1277 OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
1282 bool AsmPrinter::doFinalization(Module &M) {
1283 // Set the MachineFunction to nullptr so that we can catch attempted
1284 // accesses to MF specific features at the module level and so that
1285 // we can conditionalize accesses based on whether or not it is nullptr.
1288 // Gather all GOT equivalent globals in the module. We really need two
1289 // passes over the globals: one to compute and another to avoid its emission
1290 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1291 // where the got equivalent shows up before its use.
1292 computeGlobalGOTEquivs(M);
1294 // Emit global variables.
1295 for (const auto &G : M.globals())
1296 EmitGlobalVariable(&G);
1298 // Emit remaining GOT equivalent globals.
1299 emitGlobalGOTEquivs();
1301 // Emit visibility info for declarations
1302 for (const Function &F : M) {
1303 if (!F.isDeclarationForLinker())
1305 GlobalValue::VisibilityTypes V = F.getVisibility();
1306 if (V == GlobalValue::DefaultVisibility)
1309 MCSymbol *Name = getSymbol(&F);
1310 EmitVisibility(Name, V, false);
1313 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1315 TLOF.emitModuleMetadata(*OutStreamer, M, TM);
1317 if (TM.getTargetTriple().isOSBinFormatELF()) {
1318 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1320 // Output stubs for external and common global variables.
1321 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1322 if (!Stubs.empty()) {
1323 OutStreamer->SwitchSection(TLOF.getDataSection());
1324 const DataLayout &DL = M.getDataLayout();
1326 for (const auto &Stub : Stubs) {
1327 OutStreamer->EmitLabel(Stub.first);
1328 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1329 DL.getPointerSize());
1334 // Finalize debug and EH information.
1335 for (const HandlerInfo &HI : Handlers) {
1336 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1337 HI.TimerGroupDescription, TimePassesIsEnabled);
1338 HI.Handler->endModule();
1344 // If the target wants to know about weak references, print them all.
1345 if (MAI->getWeakRefDirective()) {
1346 // FIXME: This is not lazy, it would be nice to only print weak references
1347 // to stuff that is actually used. Note that doing so would require targets
1348 // to notice uses in operands (due to constant exprs etc). This should
1349 // happen with the MC stuff eventually.
1351 // Print out module-level global objects here.
1352 for (const auto &GO : M.global_objects()) {
1353 if (!GO.hasExternalWeakLinkage())
1355 OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
1359 OutStreamer->AddBlankLine();
1361 // Print aliases in topological order, that is, for each alias a = b,
1362 // b must be printed before a.
1363 // This is because on some targets (e.g. PowerPC) linker expects aliases in
1364 // such an order to generate correct TOC information.
1365 SmallVector<const GlobalAlias *, 16> AliasStack;
1366 SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
1367 for (const auto &Alias : M.aliases()) {
1368 for (const GlobalAlias *Cur = &Alias; Cur;
1369 Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
1370 if (!AliasVisited.insert(Cur).second)
1372 AliasStack.push_back(Cur);
1374 for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
1375 emitGlobalIndirectSymbol(M, *AncestorAlias);
1378 for (const auto &IFunc : M.ifuncs())
1379 emitGlobalIndirectSymbol(M, IFunc);
1381 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1382 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1383 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1384 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1385 MP->finishAssembly(M, *MI, *this);
1387 // Emit llvm.ident metadata in an '.ident' directive.
1388 EmitModuleIdents(M);
1390 // Emit __morestack address if needed for indirect calls.
1391 if (MMI->usesMorestackAddr()) {
1393 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1394 getDataLayout(), SectionKind::getReadOnly(),
1395 /*C=*/nullptr, Align);
1396 OutStreamer->SwitchSection(ReadOnlySection);
1398 MCSymbol *AddrSymbol =
1399 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1400 OutStreamer->EmitLabel(AddrSymbol);
1402 unsigned PtrSize = MAI->getCodePointerSize();
1403 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1407 // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if
1408 // split-stack is used.
1409 if (TM.getTargetTriple().isOSBinFormatELF() && MMI->hasSplitStack()) {
1410 OutStreamer->SwitchSection(
1411 OutContext.getELFSection(".note.GNU-split-stack", ELF::SHT_PROGBITS, 0));
1412 if (MMI->hasNosplitStack())
1413 OutStreamer->SwitchSection(
1414 OutContext.getELFSection(".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0));
1417 // If we don't have any trampolines, then we don't require stack memory
1418 // to be executable. Some targets have a directive to declare this.
1419 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1420 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1421 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1422 OutStreamer->SwitchSection(S);
1424 // Allow the target to emit any magic that it wants at the end of the file,
1425 // after everything else has gone out.
1426 EmitEndOfAsmFile(M);
1430 OutStreamer->Finish();
1431 OutStreamer->reset();
1436 MCSymbol *AsmPrinter::getCurExceptionSym() {
1437 if (!CurExceptionSym)
1438 CurExceptionSym = createTempSymbol("exception");
1439 return CurExceptionSym;
1442 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1444 // Get the function symbol.
1445 CurrentFnSym = getSymbol(&MF.getFunction());
1446 CurrentFnSymForSize = CurrentFnSym;
1447 CurrentFnBegin = nullptr;
1448 CurExceptionSym = nullptr;
1449 bool NeedsLocalForSize = MAI->needsLocalForSize();
1450 if (needFuncLabelsForEHOrDebugInfo(MF, MMI) || NeedsLocalForSize) {
1451 CurrentFnBegin = createTempSymbol("func_begin");
1452 if (NeedsLocalForSize)
1453 CurrentFnSymForSize = CurrentFnBegin;
1456 ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
1457 LI = &getAnalysis<MachineLoopInfo>();
1459 const TargetSubtargetInfo &STI = MF.getSubtarget();
1460 EnablePrintSchedInfo = PrintSchedule.getNumOccurrences()
1462 : STI.supportPrintSchedInfo();
1467 // Keep track the alignment, constpool entries per Section.
1471 SmallVector<unsigned, 4> CPEs;
1473 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1476 } // end anonymous namespace
1478 /// EmitConstantPool - Print to the current output stream assembly
1479 /// representations of the constants in the constant pool MCP. This is
1480 /// used to print out constants which have been "spilled to memory" by
1481 /// the code generator.
1482 void AsmPrinter::EmitConstantPool() {
1483 const MachineConstantPool *MCP = MF->getConstantPool();
1484 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1485 if (CP.empty()) return;
1487 // Calculate sections for constant pool entries. We collect entries to go into
1488 // the same section together to reduce amount of section switch statements.
1489 SmallVector<SectionCPs, 4> CPSections;
1490 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1491 const MachineConstantPoolEntry &CPE = CP[i];
1492 unsigned Align = CPE.getAlignment();
1494 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1496 const Constant *C = nullptr;
1497 if (!CPE.isMachineConstantPoolEntry())
1498 C = CPE.Val.ConstVal;
1500 MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
1503 // The number of sections are small, just do a linear search from the
1504 // last section to the first.
1506 unsigned SecIdx = CPSections.size();
1507 while (SecIdx != 0) {
1508 if (CPSections[--SecIdx].S == S) {
1514 SecIdx = CPSections.size();
1515 CPSections.push_back(SectionCPs(S, Align));
1518 if (Align > CPSections[SecIdx].Alignment)
1519 CPSections[SecIdx].Alignment = Align;
1520 CPSections[SecIdx].CPEs.push_back(i);
1523 // Now print stuff into the calculated sections.
1524 const MCSection *CurSection = nullptr;
1525 unsigned Offset = 0;
1526 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1527 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1528 unsigned CPI = CPSections[i].CPEs[j];
1529 MCSymbol *Sym = GetCPISymbol(CPI);
1530 if (!Sym->isUndefined())
1533 if (CurSection != CPSections[i].S) {
1534 OutStreamer->SwitchSection(CPSections[i].S);
1535 EmitAlignment(Log2_32(CPSections[i].Alignment));
1536 CurSection = CPSections[i].S;
1540 MachineConstantPoolEntry CPE = CP[CPI];
1542 // Emit inter-object padding for alignment.
1543 unsigned AlignMask = CPE.getAlignment() - 1;
1544 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1545 OutStreamer->EmitZeros(NewOffset - Offset);
1547 Type *Ty = CPE.getType();
1548 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1550 OutStreamer->EmitLabel(Sym);
1551 if (CPE.isMachineConstantPoolEntry())
1552 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1554 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1559 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1560 /// by the current function to the current output stream.
1561 void AsmPrinter::EmitJumpTableInfo() {
1562 const DataLayout &DL = MF->getDataLayout();
1563 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1565 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1566 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1567 if (JT.empty()) return;
1569 // Pick the directive to use to print the jump table entries, and switch to
1570 // the appropriate section.
1571 const Function &F = MF->getFunction();
1572 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1573 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1574 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1576 if (JTInDiffSection) {
1577 // Drop it in the readonly section.
1578 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM);
1579 OutStreamer->SwitchSection(ReadOnlySection);
1582 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1584 // Jump tables in code sections are marked with a data_region directive
1585 // where that's supported.
1586 if (!JTInDiffSection)
1587 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1589 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1590 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1592 // If this jump table was deleted, ignore it.
1593 if (JTBBs.empty()) continue;
1595 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1596 /// emit a .set directive for each unique entry.
1597 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1598 MAI->doesSetDirectiveSuppressReloc()) {
1599 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1600 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1601 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1602 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1603 const MachineBasicBlock *MBB = JTBBs[ii];
1604 if (!EmittedSets.insert(MBB).second)
1607 // .set LJTSet, LBB32-base
1609 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1610 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1611 MCBinaryExpr::createSub(LHS, Base,
1616 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1617 // before each jump table. The first label is never referenced, but tells
1618 // the assembler and linker the extents of the jump table object. The
1619 // second label is actually referenced by the code.
1620 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1621 // FIXME: This doesn't have to have any specific name, just any randomly
1622 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1623 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1625 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1627 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1628 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1630 if (!JTInDiffSection)
1631 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1634 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1636 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1637 const MachineBasicBlock *MBB,
1638 unsigned UID) const {
1639 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1640 const MCExpr *Value = nullptr;
1641 switch (MJTI->getEntryKind()) {
1642 case MachineJumpTableInfo::EK_Inline:
1643 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1644 case MachineJumpTableInfo::EK_Custom32:
1645 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1646 MJTI, MBB, UID, OutContext);
1648 case MachineJumpTableInfo::EK_BlockAddress:
1649 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1651 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1653 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1654 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1655 // with a relocation as gp-relative, e.g.:
1657 MCSymbol *MBBSym = MBB->getSymbol();
1658 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1662 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1663 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1664 // with a relocation as gp-relative, e.g.:
1666 MCSymbol *MBBSym = MBB->getSymbol();
1667 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1671 case MachineJumpTableInfo::EK_LabelDifference32: {
1672 // Each entry is the address of the block minus the address of the jump
1673 // table. This is used for PIC jump tables where gprel32 is not supported.
1675 // .word LBB123 - LJTI1_2
1676 // If the .set directive avoids relocations, this is emitted as:
1677 // .set L4_5_set_123, LBB123 - LJTI1_2
1678 // .word L4_5_set_123
1679 if (MAI->doesSetDirectiveSuppressReloc()) {
1680 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1684 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1685 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1686 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1687 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1692 assert(Value && "Unknown entry kind!");
1694 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1695 OutStreamer->EmitValue(Value, EntrySize);
1698 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1699 /// special global used by LLVM. If so, emit it and return true, otherwise
1700 /// do nothing and return false.
1701 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1702 if (GV->getName() == "llvm.used") {
1703 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1704 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1708 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1709 if (GV->getSection() == "llvm.metadata" ||
1710 GV->hasAvailableExternallyLinkage())
1713 if (!GV->hasAppendingLinkage()) return false;
1715 assert(GV->hasInitializer() && "Not a special LLVM global!");
1717 if (GV->getName() == "llvm.global_ctors") {
1718 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1724 if (GV->getName() == "llvm.global_dtors") {
1725 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1726 /* isCtor */ false);
1731 report_fatal_error("unknown special variable");
1734 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1735 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1736 /// is true, as being used with this directive.
1737 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1738 // Should be an array of 'i8*'.
1739 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1740 const GlobalValue *GV =
1741 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1743 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1751 Constant *Func = nullptr;
1752 GlobalValue *ComdatKey = nullptr;
1754 Structor() = default;
1757 } // end anonymous namespace
1759 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1761 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1763 // Should be an array of '{ int, void ()* }' structs. The first value is the
1765 if (!isa<ConstantArray>(List)) return;
1767 // Sanity check the structors list.
1768 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1769 if (!InitList) return; // Not an array!
1770 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1771 // FIXME: Only allow the 3-field form in LLVM 4.0.
1772 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1773 return; // Not an array of two or three elements!
1774 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1775 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1776 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1777 return; // Not (int, ptr, ptr).
1779 // Gather the structors in a form that's convenient for sorting by priority.
1780 SmallVector<Structor, 8> Structors;
1781 for (Value *O : InitList->operands()) {
1782 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1783 if (!CS) continue; // Malformed.
1784 if (CS->getOperand(1)->isNullValue())
1785 break; // Found a null terminator, skip the rest.
1786 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1787 if (!Priority) continue; // Malformed.
1788 Structors.push_back(Structor());
1789 Structor &S = Structors.back();
1790 S.Priority = Priority->getLimitedValue(65535);
1791 S.Func = CS->getOperand(1);
1792 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1794 dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1797 // Emit the function pointers in the target-specific order
1798 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1799 std::stable_sort(Structors.begin(), Structors.end(),
1800 [](const Structor &L,
1801 const Structor &R) { return L.Priority < R.Priority; });
1802 for (Structor &S : Structors) {
1803 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1804 const MCSymbol *KeySym = nullptr;
1805 if (GlobalValue *GV = S.ComdatKey) {
1806 if (GV->isDeclarationForLinker())
1807 // If the associated variable is not defined in this module
1808 // (it might be available_externally, or have been an
1809 // available_externally definition that was dropped by the
1810 // EliminateAvailableExternally pass), some other TU
1811 // will provide its dynamic initializer.
1814 KeySym = getSymbol(GV);
1816 MCSection *OutputSection =
1817 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1818 : Obj.getStaticDtorSection(S.Priority, KeySym));
1819 OutStreamer->SwitchSection(OutputSection);
1820 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1821 EmitAlignment(Align);
1822 EmitXXStructor(DL, S.Func);
1826 void AsmPrinter::EmitModuleIdents(Module &M) {
1827 if (!MAI->hasIdentDirective())
1830 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1831 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1832 const MDNode *N = NMD->getOperand(i);
1833 assert(N->getNumOperands() == 1 &&
1834 "llvm.ident metadata entry can have only one operand");
1835 const MDString *S = cast<MDString>(N->getOperand(0));
1836 OutStreamer->EmitIdent(S->getString());
1841 //===--------------------------------------------------------------------===//
1842 // Emission and print routines
1845 /// EmitInt8 - Emit a byte directive and value.
1847 void AsmPrinter::EmitInt8(int Value) const {
1848 OutStreamer->EmitIntValue(Value, 1);
1851 /// EmitInt16 - Emit a short directive and value.
1852 void AsmPrinter::EmitInt16(int Value) const {
1853 OutStreamer->EmitIntValue(Value, 2);
1856 /// EmitInt32 - Emit a long directive and value.
1857 void AsmPrinter::EmitInt32(int Value) const {
1858 OutStreamer->EmitIntValue(Value, 4);
1861 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1862 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1863 /// .set if it avoids relocations.
1864 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1865 unsigned Size) const {
1866 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
1869 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1870 /// where the size in bytes of the directive is specified by Size and Label
1871 /// specifies the label. This implicitly uses .set if it is available.
1872 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1874 bool IsSectionRelative) const {
1875 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1876 OutStreamer->EmitCOFFSecRel32(Label, Offset);
1878 OutStreamer->EmitZeros(Size - 4);
1882 // Emit Label+Offset (or just Label if Offset is zero)
1883 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
1885 Expr = MCBinaryExpr::createAdd(
1886 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
1888 OutStreamer->EmitValue(Expr, Size);
1891 //===----------------------------------------------------------------------===//
1893 // EmitAlignment - Emit an alignment directive to the specified power of
1894 // two boundary. For example, if you pass in 3 here, you will get an 8
1895 // byte alignment. If a global value is specified, and if that global has
1896 // an explicit alignment requested, it will override the alignment request
1897 // if required for correctness.
1898 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1900 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
1902 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1905 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1906 "undefined behavior");
1907 if (getCurrentSection()->getKind().isText())
1908 OutStreamer->EmitCodeAlignment(1u << NumBits);
1910 OutStreamer->EmitValueToAlignment(1u << NumBits);
1913 //===----------------------------------------------------------------------===//
1914 // Constant emission.
1915 //===----------------------------------------------------------------------===//
1917 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1918 MCContext &Ctx = OutContext;
1920 if (CV->isNullValue() || isa<UndefValue>(CV))
1921 return MCConstantExpr::create(0, Ctx);
1923 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1924 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
1926 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1927 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
1929 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1930 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
1932 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1934 llvm_unreachable("Unknown constant value to lower!");
1937 switch (CE->getOpcode()) {
1939 // If the code isn't optimized, there may be outstanding folding
1940 // opportunities. Attempt to fold the expression using DataLayout as a
1941 // last resort before giving up.
1942 if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
1944 return lowerConstant(C);
1946 // Otherwise report the problem to the user.
1949 raw_string_ostream OS(S);
1950 OS << "Unsupported expression in static initializer: ";
1951 CE->printAsOperand(OS, /*PrintType=*/false,
1952 !MF ? nullptr : MF->getFunction().getParent());
1953 report_fatal_error(OS.str());
1955 case Instruction::GetElementPtr: {
1956 // Generate a symbolic expression for the byte address
1957 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
1958 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
1960 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1964 int64_t Offset = OffsetAI.getSExtValue();
1965 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
1969 case Instruction::Trunc:
1970 // We emit the value and depend on the assembler to truncate the generated
1971 // expression properly. This is important for differences between
1972 // blockaddress labels. Since the two labels are in the same function, it
1973 // is reasonable to treat their delta as a 32-bit value.
1975 case Instruction::BitCast:
1976 return lowerConstant(CE->getOperand(0));
1978 case Instruction::IntToPtr: {
1979 const DataLayout &DL = getDataLayout();
1981 // Handle casts to pointers by changing them into casts to the appropriate
1982 // integer type. This promotes constant folding and simplifies this code.
1983 Constant *Op = CE->getOperand(0);
1984 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1986 return lowerConstant(Op);
1989 case Instruction::PtrToInt: {
1990 const DataLayout &DL = getDataLayout();
1992 // Support only foldable casts to/from pointers that can be eliminated by
1993 // changing the pointer to the appropriately sized integer type.
1994 Constant *Op = CE->getOperand(0);
1995 Type *Ty = CE->getType();
1997 const MCExpr *OpExpr = lowerConstant(Op);
1999 // We can emit the pointer value into this slot if the slot is an
2000 // integer slot equal to the size of the pointer.
2001 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
2004 // Otherwise the pointer is smaller than the resultant integer, mask off
2005 // the high bits so we are sure to get a proper truncation if the input is
2007 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
2008 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
2009 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
2012 case Instruction::Sub: {
2015 if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
2019 if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
2021 const MCExpr *RelocExpr =
2022 getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM);
2024 RelocExpr = MCBinaryExpr::createSub(
2025 MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx),
2026 MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
2027 int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
2029 RelocExpr = MCBinaryExpr::createAdd(
2030 RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
2038 // The MC library also has a right-shift operator, but it isn't consistently
2039 // signed or unsigned between different targets.
2040 case Instruction::Add:
2041 case Instruction::Mul:
2042 case Instruction::SDiv:
2043 case Instruction::SRem:
2044 case Instruction::Shl:
2045 case Instruction::And:
2046 case Instruction::Or:
2047 case Instruction::Xor: {
2048 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
2049 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
2050 switch (CE->getOpcode()) {
2051 default: llvm_unreachable("Unknown binary operator constant cast expr");
2052 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
2053 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
2054 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
2055 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
2056 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
2057 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
2058 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
2059 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
2060 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
2066 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
2068 const Constant *BaseCV = nullptr,
2069 uint64_t Offset = 0);
2071 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
2073 /// isRepeatedByteSequence - Determine whether the given value is
2074 /// composed of a repeated sequence of identical bytes and return the
2075 /// byte value. If it is not a repeated sequence, return -1.
2076 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
2077 StringRef Data = V->getRawDataValues();
2078 assert(!Data.empty() && "Empty aggregates should be CAZ node");
2080 for (unsigned i = 1, e = Data.size(); i != e; ++i)
2081 if (Data[i] != C) return -1;
2082 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
2085 /// isRepeatedByteSequence - Determine whether the given value is
2086 /// composed of a repeated sequence of identical bytes and return the
2087 /// byte value. If it is not a repeated sequence, return -1.
2088 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
2089 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
2090 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
2091 assert(Size % 8 == 0);
2093 // Extend the element to take zero padding into account.
2094 APInt Value = CI->getValue().zextOrSelf(Size);
2095 if (!Value.isSplat(8))
2098 return Value.zextOrTrunc(8).getZExtValue();
2100 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
2101 // Make sure all array elements are sequences of the same repeated
2103 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
2104 Constant *Op0 = CA->getOperand(0);
2105 int Byte = isRepeatedByteSequence(Op0, DL);
2109 // All array elements must be equal.
2110 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
2111 if (CA->getOperand(i) != Op0)
2116 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
2117 return isRepeatedByteSequence(CDS);
2122 static void emitGlobalConstantDataSequential(const DataLayout &DL,
2123 const ConstantDataSequential *CDS,
2125 // See if we can aggregate this into a .fill, if so, emit it as such.
2126 int Value = isRepeatedByteSequence(CDS, DL);
2128 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
2129 // Don't emit a 1-byte object as a .fill.
2131 return AP.OutStreamer->emitFill(Bytes, Value);
2134 // If this can be emitted with .ascii/.asciz, emit it as such.
2135 if (CDS->isString())
2136 return AP.OutStreamer->EmitBytes(CDS->getAsString());
2138 // Otherwise, emit the values in successive locations.
2139 unsigned ElementByteSize = CDS->getElementByteSize();
2140 if (isa<IntegerType>(CDS->getElementType())) {
2141 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
2143 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2144 CDS->getElementAsInteger(i));
2145 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
2149 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I)
2150 emitGlobalConstantFP(cast<ConstantFP>(CDS->getElementAsConstant(I)), AP);
2153 unsigned Size = DL.getTypeAllocSize(CDS->getType());
2154 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
2155 CDS->getNumElements();
2156 if (unsigned Padding = Size - EmittedSize)
2157 AP.OutStreamer->EmitZeros(Padding);
2160 static void emitGlobalConstantArray(const DataLayout &DL,
2161 const ConstantArray *CA, AsmPrinter &AP,
2162 const Constant *BaseCV, uint64_t Offset) {
2163 // See if we can aggregate some values. Make sure it can be
2164 // represented as a series of bytes of the constant value.
2165 int Value = isRepeatedByteSequence(CA, DL);
2168 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2169 AP.OutStreamer->emitFill(Bytes, Value);
2172 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2173 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2174 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2179 static void emitGlobalConstantVector(const DataLayout &DL,
2180 const ConstantVector *CV, AsmPrinter &AP) {
2181 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2182 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2184 unsigned Size = DL.getTypeAllocSize(CV->getType());
2185 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2186 CV->getType()->getNumElements();
2187 if (unsigned Padding = Size - EmittedSize)
2188 AP.OutStreamer->EmitZeros(Padding);
2191 static void emitGlobalConstantStruct(const DataLayout &DL,
2192 const ConstantStruct *CS, AsmPrinter &AP,
2193 const Constant *BaseCV, uint64_t Offset) {
2194 // Print the fields in successive locations. Pad to align if needed!
2195 unsigned Size = DL.getTypeAllocSize(CS->getType());
2196 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2197 uint64_t SizeSoFar = 0;
2198 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2199 const Constant *Field = CS->getOperand(i);
2201 // Print the actual field value.
2202 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2204 // Check if padding is needed and insert one or more 0s.
2205 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2206 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2207 - Layout->getElementOffset(i)) - FieldSize;
2208 SizeSoFar += FieldSize + PadSize;
2210 // Insert padding - this may include padding to increase the size of the
2211 // current field up to the ABI size (if the struct is not packed) as well
2212 // as padding to ensure that the next field starts at the right offset.
2213 AP.OutStreamer->EmitZeros(PadSize);
2215 assert(SizeSoFar == Layout->getSizeInBytes() &&
2216 "Layout of constant struct may be incorrect!");
2219 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2220 APInt API = CFP->getValueAPF().bitcastToAPInt();
2222 // First print a comment with what we think the original floating-point value
2223 // should have been.
2224 if (AP.isVerbose()) {
2225 SmallString<8> StrVal;
2226 CFP->getValueAPF().toString(StrVal);
2229 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
2231 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2232 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2235 // Now iterate through the APInt chunks, emitting them in endian-correct
2236 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2238 unsigned NumBytes = API.getBitWidth() / 8;
2239 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2240 const uint64_t *p = API.getRawData();
2242 // PPC's long double has odd notions of endianness compared to how LLVM
2243 // handles it: p[0] goes first for *big* endian on PPC.
2244 if (AP.getDataLayout().isBigEndian() && !CFP->getType()->isPPC_FP128Ty()) {
2245 int Chunk = API.getNumWords() - 1;
2248 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2250 for (; Chunk >= 0; --Chunk)
2251 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2254 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2255 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2258 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2261 // Emit the tail padding for the long double.
2262 const DataLayout &DL = AP.getDataLayout();
2263 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2264 DL.getTypeStoreSize(CFP->getType()));
2267 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2268 const DataLayout &DL = AP.getDataLayout();
2269 unsigned BitWidth = CI->getBitWidth();
2271 // Copy the value as we may massage the layout for constants whose bit width
2272 // is not a multiple of 64-bits.
2273 APInt Realigned(CI->getValue());
2274 uint64_t ExtraBits = 0;
2275 unsigned ExtraBitsSize = BitWidth & 63;
2277 if (ExtraBitsSize) {
2278 // The bit width of the data is not a multiple of 64-bits.
2279 // The extra bits are expected to be at the end of the chunk of the memory.
2281 // * Nothing to be done, just record the extra bits to emit.
2283 // * Record the extra bits to emit.
2284 // * Realign the raw data to emit the chunks of 64-bits.
2285 if (DL.isBigEndian()) {
2286 // Basically the structure of the raw data is a chunk of 64-bits cells:
2287 // 0 1 BitWidth / 64
2288 // [chunk1][chunk2] ... [chunkN].
2289 // The most significant chunk is chunkN and it should be emitted first.
2290 // However, due to the alignment issue chunkN contains useless bits.
2291 // Realign the chunks so that they contain only useless information:
2292 // ExtraBits 0 1 (BitWidth / 64) - 1
2293 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2294 ExtraBits = Realigned.getRawData()[0] &
2295 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2296 Realigned.lshrInPlace(ExtraBitsSize);
2298 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2301 // We don't expect assemblers to support integer data directives
2302 // for more than 64 bits, so we emit the data in at most 64-bit
2303 // quantities at a time.
2304 const uint64_t *RawData = Realigned.getRawData();
2305 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2306 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2307 AP.OutStreamer->EmitIntValue(Val, 8);
2310 if (ExtraBitsSize) {
2311 // Emit the extra bits after the 64-bits chunks.
2313 // Emit a directive that fills the expected size.
2314 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2315 Size -= (BitWidth / 64) * 8;
2316 assert(Size && Size * 8 >= ExtraBitsSize &&
2317 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2318 == ExtraBits && "Directive too small for extra bits.");
2319 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2323 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2324 /// equivalent global, by a target specific GOT pc relative access to the
2326 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2327 const Constant *BaseCst,
2329 // The global @foo below illustrates a global that uses a got equivalent.
2331 // @bar = global i32 42
2332 // @gotequiv = private unnamed_addr constant i32* @bar
2333 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2334 // i64 ptrtoint (i32* @foo to i64))
2337 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2338 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2341 // foo = cstexpr, where
2342 // cstexpr := <gotequiv> - "." + <cst>
2343 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2345 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2347 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2348 // gotpcrelcst := <offset from @foo base> + <cst>
2350 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2352 const MCSymbolRefExpr *SymA = MV.getSymA();
2356 // Check that GOT equivalent symbol is cached.
2357 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2358 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2361 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2365 // Check for a valid base symbol
2366 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2367 const MCSymbolRefExpr *SymB = MV.getSymB();
2369 if (!SymB || BaseSym != &SymB->getSymbol())
2372 // Make sure to match:
2374 // gotpcrelcst := <offset from @foo base> + <cst>
2376 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2377 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2378 // if the target knows how to encode it.
2379 int64_t GOTPCRelCst = Offset + MV.getConstant();
2380 if (GOTPCRelCst < 0)
2382 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2385 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2392 // .long gotequiv - "." + <cst>
2394 // is replaced by the target specific equivalent to:
2399 // .long bar@GOTPCREL+<gotpcrelcst>
2400 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2401 const GlobalVariable *GV = Result.first;
2402 int NumUses = (int)Result.second;
2403 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2404 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2405 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2406 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2408 // Update GOT equivalent usage information
2411 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2414 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2415 AsmPrinter &AP, const Constant *BaseCV,
2417 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2419 // Globals with sub-elements such as combinations of arrays and structs
2420 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2421 // constant symbol base and the current position with BaseCV and Offset.
2422 if (!BaseCV && CV->hasOneUse())
2423 BaseCV = dyn_cast<Constant>(CV->user_back());
2425 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2426 return AP.OutStreamer->EmitZeros(Size);
2428 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2435 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2436 CI->getZExtValue());
2437 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2440 emitGlobalConstantLargeInt(CI, AP);
2445 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2446 return emitGlobalConstantFP(CFP, AP);
2448 if (isa<ConstantPointerNull>(CV)) {
2449 AP.OutStreamer->EmitIntValue(0, Size);
2453 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2454 return emitGlobalConstantDataSequential(DL, CDS, AP);
2456 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2457 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2459 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2460 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2462 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2463 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2465 if (CE->getOpcode() == Instruction::BitCast)
2466 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2469 // If the constant expression's size is greater than 64-bits, then we have
2470 // to emit the value in chunks. Try to constant fold the value and emit it
2472 Constant *New = ConstantFoldConstant(CE, DL);
2473 if (New && New != CE)
2474 return emitGlobalConstantImpl(DL, New, AP);
2478 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2479 return emitGlobalConstantVector(DL, V, AP);
2481 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2482 // thread the streamer with EmitValue.
2483 const MCExpr *ME = AP.lowerConstant(CV);
2485 // Since lowerConstant already folded and got rid of all IR pointer and
2486 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2488 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2489 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2491 AP.OutStreamer->EmitValue(ME, Size);
2494 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2495 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2496 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2498 emitGlobalConstantImpl(DL, CV, *this);
2499 else if (MAI->hasSubsectionsViaSymbols()) {
2500 // If the global has zero size, emit a single byte so that two labels don't
2501 // look like they are at the same location.
2502 OutStreamer->EmitIntValue(0, 1);
2506 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2507 // Target doesn't support this yet!
2508 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2511 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2513 OS << '+' << Offset;
2514 else if (Offset < 0)
2518 //===----------------------------------------------------------------------===//
2519 // Symbol Lowering Routines.
2520 //===----------------------------------------------------------------------===//
2522 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2523 return OutContext.createTempSymbol(Name, true);
2526 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2527 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2530 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2531 return MMI->getAddrLabelSymbol(BB);
2534 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2535 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2536 const DataLayout &DL = getDataLayout();
2537 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2538 "CPI" + Twine(getFunctionNumber()) + "_" +
2542 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2543 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2544 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2547 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2548 /// FIXME: privatize to AsmPrinter.
2549 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2550 const DataLayout &DL = getDataLayout();
2551 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2552 Twine(getFunctionNumber()) + "_" +
2553 Twine(UID) + "_set_" + Twine(MBBID));
2556 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2557 StringRef Suffix) const {
2558 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM);
2561 /// Return the MCSymbol for the specified ExternalSymbol.
2562 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2563 SmallString<60> NameStr;
2564 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2565 return OutContext.getOrCreateSymbol(NameStr);
2568 /// PrintParentLoopComment - Print comments about parent loops of this one.
2569 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2570 unsigned FunctionNumber) {
2572 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2573 OS.indent(Loop->getLoopDepth()*2)
2574 << "Parent Loop BB" << FunctionNumber << "_"
2575 << Loop->getHeader()->getNumber()
2576 << " Depth=" << Loop->getLoopDepth() << '\n';
2579 /// PrintChildLoopComment - Print comments about child loops within
2580 /// the loop for this basic block, with nesting.
2581 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2582 unsigned FunctionNumber) {
2583 // Add child loop information
2584 for (const MachineLoop *CL : *Loop) {
2585 OS.indent(CL->getLoopDepth()*2)
2586 << "Child Loop BB" << FunctionNumber << "_"
2587 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2589 PrintChildLoopComment(OS, CL, FunctionNumber);
2593 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2594 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2595 const MachineLoopInfo *LI,
2596 const AsmPrinter &AP) {
2597 // Add loop depth information
2598 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2601 MachineBasicBlock *Header = Loop->getHeader();
2602 assert(Header && "No header for loop");
2604 // If this block is not a loop header, just print out what is the loop header
2606 if (Header != &MBB) {
2607 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2608 Twine(AP.getFunctionNumber())+"_" +
2609 Twine(Loop->getHeader()->getNumber())+
2610 " Depth="+Twine(Loop->getLoopDepth()));
2614 // Otherwise, it is a loop header. Print out information about child and
2616 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2618 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2621 OS.indent(Loop->getLoopDepth()*2-2);
2626 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2628 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2631 void AsmPrinter::setupCodePaddingContext(const MachineBasicBlock &MBB,
2632 MCCodePaddingContext &Context) const {
2633 assert(MF != nullptr && "Machine function must be valid");
2634 assert(LI != nullptr && "Loop info must be valid");
2635 Context.IsPaddingActive = !MF->hasInlineAsm() &&
2636 !MF->getFunction().optForSize() &&
2637 TM.getOptLevel() != CodeGenOpt::None;
2638 const MachineLoop *CurrentLoop = LI->getLoopFor(&MBB);
2639 Context.IsBasicBlockInsideInnermostLoop =
2640 CurrentLoop != nullptr && CurrentLoop->getSubLoops().empty();
2641 Context.IsBasicBlockReachableViaFallthrough =
2642 std::find(MBB.pred_begin(), MBB.pred_end(), MBB.getPrevNode()) !=
2644 Context.IsBasicBlockReachableViaBranch =
2645 MBB.pred_size() > 0 && !isBlockOnlyReachableByFallthrough(&MBB);
2648 /// EmitBasicBlockStart - This method prints the label for the specified
2649 /// MachineBasicBlock, an alignment (if present) and a comment describing
2650 /// it if appropriate.
2651 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2652 // End the previous funclet and start a new one.
2653 if (MBB.isEHFuncletEntry()) {
2654 for (const HandlerInfo &HI : Handlers) {
2655 HI.Handler->endFunclet();
2656 HI.Handler->beginFunclet(MBB);
2660 // Emit an alignment directive for this block, if needed.
2661 if (unsigned Align = MBB.getAlignment())
2662 EmitAlignment(Align);
2663 MCCodePaddingContext Context;
2664 setupCodePaddingContext(MBB, Context);
2665 OutStreamer->EmitCodePaddingBasicBlockStart(Context);
2667 // If the block has its address taken, emit any labels that were used to
2668 // reference the block. It is possible that there is more than one label
2669 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2670 // the references were generated.
2671 if (MBB.hasAddressTaken()) {
2672 const BasicBlock *BB = MBB.getBasicBlock();
2674 OutStreamer->AddComment("Block address taken");
2676 // MBBs can have their address taken as part of CodeGen without having
2677 // their corresponding BB's address taken in IR
2678 if (BB->hasAddressTaken())
2679 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2680 OutStreamer->EmitLabel(Sym);
2683 // Print some verbose block comments.
2685 if (const BasicBlock *BB = MBB.getBasicBlock()) {
2686 if (BB->hasName()) {
2687 BB->printAsOperand(OutStreamer->GetCommentOS(),
2688 /*PrintType=*/false, BB->getModule());
2689 OutStreamer->GetCommentOS() << '\n';
2692 emitBasicBlockLoopComments(MBB, LI, *this);
2695 // Print the main label for the block.
2696 if (MBB.pred_empty() ||
2697 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2699 // NOTE: Want this comment at start of line, don't emit with AddComment.
2700 OutStreamer->emitRawComment(" %bb." + Twine(MBB.getNumber()) + ":",
2704 OutStreamer->EmitLabel(MBB.getSymbol());
2708 void AsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) {
2709 MCCodePaddingContext Context;
2710 setupCodePaddingContext(MBB, Context);
2711 OutStreamer->EmitCodePaddingBasicBlockEnd(Context);
2714 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2715 bool IsDefinition) const {
2716 MCSymbolAttr Attr = MCSA_Invalid;
2718 switch (Visibility) {
2720 case GlobalValue::HiddenVisibility:
2722 Attr = MAI->getHiddenVisibilityAttr();
2724 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2726 case GlobalValue::ProtectedVisibility:
2727 Attr = MAI->getProtectedVisibilityAttr();
2731 if (Attr != MCSA_Invalid)
2732 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2735 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2736 /// exactly one predecessor and the control transfer mechanism between
2737 /// the predecessor and this block is a fall-through.
2739 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2740 // If this is a landing pad, it isn't a fall through. If it has no preds,
2741 // then nothing falls through to it.
2742 if (MBB->isEHPad() || MBB->pred_empty())
2745 // If there isn't exactly one predecessor, it can't be a fall through.
2746 if (MBB->pred_size() > 1)
2749 // The predecessor has to be immediately before this block.
2750 MachineBasicBlock *Pred = *MBB->pred_begin();
2751 if (!Pred->isLayoutSuccessor(MBB))
2754 // If the block is completely empty, then it definitely does fall through.
2758 // Check the terminators in the previous blocks
2759 for (const auto &MI : Pred->terminators()) {
2760 // If it is not a simple branch, we are in a table somewhere.
2761 if (!MI.isBranch() || MI.isIndirectBranch())
2764 // If we are the operands of one of the branches, this is not a fall
2765 // through. Note that targets with delay slots will usually bundle
2766 // terminators with the delay slot instruction.
2767 for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
2770 if (OP->isMBB() && OP->getMBB() == MBB)
2778 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2779 if (!S.usesMetadata())
2782 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2783 " stackmap formats, please see the documentation for a description of"
2784 " the default format. If you really need a custom serialized format,"
2785 " please file a bug");
2787 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2788 gcp_map_type::iterator GCPI = GCMap.find(&S);
2789 if (GCPI != GCMap.end())
2790 return GCPI->second.get();
2792 auto Name = S.getName();
2794 for (GCMetadataPrinterRegistry::iterator
2795 I = GCMetadataPrinterRegistry::begin(),
2796 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2797 if (Name == I->getName()) {
2798 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2800 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2801 return IterBool.first->second.get();
2804 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2807 /// Pin vtable to this file.
2808 AsmPrinterHandler::~AsmPrinterHandler() = default;
2810 void AsmPrinterHandler::markFunctionEnd() {}
2812 // In the binary's "xray_instr_map" section, an array of these function entries
2813 // describes each instrumentation point. When XRay patches your code, the index
2814 // into this table will be given to your handler as a patch point identifier.
2815 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out,
2816 const MCSymbol *CurrentFnSym) const {
2817 Out->EmitSymbolValue(Sled, Bytes);
2818 Out->EmitSymbolValue(CurrentFnSym, Bytes);
2819 auto Kind8 = static_cast<uint8_t>(Kind);
2820 Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
2821 Out->EmitBinaryData(
2822 StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
2823 Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Version), 1));
2824 auto Padding = (4 * Bytes) - ((2 * Bytes) + 3);
2825 assert(Padding >= 0 && "Instrumentation map entry > 4 * Word Size");
2826 Out->EmitZeros(Padding);
2829 void AsmPrinter::emitXRayTable() {
2833 auto PrevSection = OutStreamer->getCurrentSectionOnly();
2834 const Function &F = MF->getFunction();
2835 MCSection *InstMap = nullptr;
2836 MCSection *FnSledIndex = nullptr;
2837 if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) {
2838 auto Associated = dyn_cast<MCSymbolELF>(CurrentFnSym);
2839 assert(Associated != nullptr);
2840 auto Flags = ELF::SHF_WRITE | ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER;
2841 std::string GroupName;
2842 if (F.hasComdat()) {
2843 Flags |= ELF::SHF_GROUP;
2844 GroupName = F.getComdat()->getName();
2847 auto UniqueID = ++XRayFnUniqueID;
2849 OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS, Flags, 0,
2850 GroupName, UniqueID, Associated);
2852 OutContext.getELFSection("xray_fn_idx", ELF::SHT_PROGBITS, Flags, 0,
2853 GroupName, UniqueID, Associated);
2854 } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
2855 InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map", 0,
2856 SectionKind::getReadOnlyWithRel());
2857 FnSledIndex = OutContext.getMachOSection("__DATA", "xray_fn_idx", 0,
2858 SectionKind::getReadOnlyWithRel());
2860 llvm_unreachable("Unsupported target");
2863 auto WordSizeBytes = MAI->getCodePointerSize();
2865 // Now we switch to the instrumentation map section. Because this is done
2866 // per-function, we are able to create an index entry that will represent the
2867 // range of sleds associated with a function.
2868 MCSymbol *SledsStart = OutContext.createTempSymbol("xray_sleds_start", true);
2869 OutStreamer->SwitchSection(InstMap);
2870 OutStreamer->EmitLabel(SledsStart);
2871 for (const auto &Sled : Sleds)
2872 Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym);
2873 MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_sleds_end", true);
2874 OutStreamer->EmitLabel(SledsEnd);
2876 // We then emit a single entry in the index per function. We use the symbols
2877 // that bound the instrumentation map as the range for a specific function.
2878 // Each entry here will be 2 * word size aligned, as we're writing down two
2879 // pointers. This should work for both 32-bit and 64-bit platforms.
2880 OutStreamer->SwitchSection(FnSledIndex);
2881 OutStreamer->EmitCodeAlignment(2 * WordSizeBytes);
2882 OutStreamer->EmitSymbolValue(SledsStart, WordSizeBytes, false);
2883 OutStreamer->EmitSymbolValue(SledsEnd, WordSizeBytes, false);
2884 OutStreamer->SwitchSection(PrevSection);
2888 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
2889 SledKind Kind, uint8_t Version) {
2890 const Function &F = MI.getMF()->getFunction();
2891 auto Attr = F.getFnAttribute("function-instrument");
2892 bool LogArgs = F.hasFnAttribute("xray-log-args");
2893 bool AlwaysInstrument =
2894 Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always";
2895 if (Kind == SledKind::FUNCTION_ENTER && LogArgs)
2896 Kind = SledKind::LOG_ARGS_ENTER;
2897 Sleds.emplace_back(XRayFunctionEntry{Sled, CurrentFnSym, Kind,
2898 AlwaysInstrument, &F, Version});
2901 uint16_t AsmPrinter::getDwarfVersion() const {
2902 return OutStreamer->getContext().getDwarfVersion();
2905 void AsmPrinter::setDwarfVersion(uint16_t Version) {
2906 OutStreamer->getContext().setDwarfVersion(Version);