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 "AsmPrinterHandler.h"
15 #include "CodeViewDebug.h"
16 #include "DwarfDebug.h"
17 #include "DwarfException.h"
18 #include "WinException.h"
19 #include "llvm/ADT/APFloat.h"
20 #include "llvm/ADT/APInt.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/Statistic.h"
26 #include "llvm/ADT/STLExtras.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/ADT/Twine.h"
30 #include "llvm/Analysis/ConstantFolding.h"
31 #include "llvm/Analysis/ObjectUtils.h"
32 #include "llvm/CodeGen/Analysis.h"
33 #include "llvm/CodeGen/AsmPrinter.h"
34 #include "llvm/CodeGen/GCMetadata.h"
35 #include "llvm/CodeGen/GCMetadataPrinter.h"
36 #include "llvm/CodeGen/GCStrategy.h"
37 #include "llvm/CodeGen/MachineBasicBlock.h"
38 #include "llvm/CodeGen/MachineConstantPool.h"
39 #include "llvm/CodeGen/MachineFrameInfo.h"
40 #include "llvm/CodeGen/MachineFunction.h"
41 #include "llvm/CodeGen/MachineFunctionPass.h"
42 #include "llvm/CodeGen/MachineInstr.h"
43 #include "llvm/CodeGen/MachineInstrBundle.h"
44 #include "llvm/CodeGen/MachineJumpTableInfo.h"
45 #include "llvm/CodeGen/MachineLoopInfo.h"
46 #include "llvm/CodeGen/MachineMemOperand.h"
47 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
48 #include "llvm/CodeGen/MachineOperand.h"
49 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
50 #include "llvm/IR/BasicBlock.h"
51 #include "llvm/IR/Constant.h"
52 #include "llvm/IR/Constants.h"
53 #include "llvm/IR/DataLayout.h"
54 #include "llvm/IR/DebugInfoMetadata.h"
55 #include "llvm/IR/DerivedTypes.h"
56 #include "llvm/IR/Function.h"
57 #include "llvm/IR/GlobalAlias.h"
58 #include "llvm/IR/GlobalIFunc.h"
59 #include "llvm/IR/GlobalIndirectSymbol.h"
60 #include "llvm/IR/GlobalObject.h"
61 #include "llvm/IR/GlobalValue.h"
62 #include "llvm/IR/GlobalVariable.h"
63 #include "llvm/IR/Mangler.h"
64 #include "llvm/IR/Metadata.h"
65 #include "llvm/IR/Module.h"
66 #include "llvm/IR/Operator.h"
67 #include "llvm/IR/Value.h"
68 #include "llvm/MC/MCAsmInfo.h"
69 #include "llvm/MC/MCContext.h"
70 #include "llvm/MC/MCDirectives.h"
71 #include "llvm/MC/MCExpr.h"
72 #include "llvm/MC/MCInst.h"
73 #include "llvm/MC/MCSection.h"
74 #include "llvm/MC/MCSectionELF.h"
75 #include "llvm/MC/MCSectionMachO.h"
76 #include "llvm/MC/MCStreamer.h"
77 #include "llvm/MC/MCSubtargetInfo.h"
78 #include "llvm/MC/MCSymbol.h"
79 #include "llvm/MC/MCTargetOptions.h"
80 #include "llvm/MC/MCValue.h"
81 #include "llvm/MC/SectionKind.h"
82 #include "llvm/Pass.h"
83 #include "llvm/Support/Casting.h"
84 #include "llvm/Support/Compiler.h"
85 #include "llvm/Support/Dwarf.h"
86 #include "llvm/Support/ELF.h"
87 #include "llvm/Support/ErrorHandling.h"
88 #include "llvm/Support/Format.h"
89 #include "llvm/Support/MathExtras.h"
90 #include "llvm/Support/raw_ostream.h"
91 #include "llvm/Support/TargetRegistry.h"
92 #include "llvm/Support/Timer.h"
93 #include "llvm/Target/TargetFrameLowering.h"
94 #include "llvm/Target/TargetInstrInfo.h"
95 #include "llvm/Target/TargetLowering.h"
96 #include "llvm/Target/TargetLoweringObjectFile.h"
97 #include "llvm/Target/TargetMachine.h"
98 #include "llvm/Target/TargetRegisterInfo.h"
99 #include "llvm/Target/TargetSubtargetInfo.h"
110 using namespace llvm;
112 #define DEBUG_TYPE "asm-printer"
114 static const char *const DWARFGroupName = "dwarf";
115 static const char *const DWARFGroupDescription = "DWARF Emission";
116 static const char *const DbgTimerName = "emit";
117 static const char *const DbgTimerDescription = "Debug Info Emission";
118 static const char *const EHTimerName = "write_exception";
119 static const char *const EHTimerDescription = "DWARF Exception Writer";
120 static const char *const CodeViewLineTablesGroupName = "linetables";
121 static const char *const CodeViewLineTablesGroupDescription =
122 "CodeView Line Tables";
124 STATISTIC(EmittedInsts, "Number of machine instrs printed");
127 PrintSchedule("print-schedule", cl::Hidden, cl::init(false),
128 cl::desc("Print 'sched: [latency:throughput]' in .s output"));
130 char AsmPrinter::ID = 0;
132 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
133 static gcp_map_type &getGCMap(void *&P) {
135 P = new gcp_map_type();
136 return *(gcp_map_type*)P;
139 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
140 /// value in log2 form. This rounds up to the preferred alignment if possible
142 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
143 unsigned InBits = 0) {
144 unsigned NumBits = 0;
145 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
146 NumBits = DL.getPreferredAlignmentLog(GVar);
148 // If InBits is specified, round it to it.
149 if (InBits > NumBits)
152 // If the GV has a specified alignment, take it into account.
153 if (GV->getAlignment() == 0)
156 unsigned GVAlign = Log2_32(GV->getAlignment());
158 // If the GVAlign is larger than NumBits, or if we are required to obey
159 // NumBits because the GV has an assigned section, obey it.
160 if (GVAlign > NumBits || GV->hasSection())
165 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
166 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
167 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) {
168 VerboseAsm = OutStreamer->isVerboseAsm();
171 AsmPrinter::~AsmPrinter() {
172 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
174 if (GCMetadataPrinters) {
175 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
178 GCMetadataPrinters = nullptr;
182 bool AsmPrinter::isPositionIndependent() const {
183 return TM.isPositionIndependent();
186 /// getFunctionNumber - Return a unique ID for the current function.
188 unsigned AsmPrinter::getFunctionNumber() const {
189 return MF->getFunctionNumber();
192 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
193 return *TM.getObjFileLowering();
196 const DataLayout &AsmPrinter::getDataLayout() const {
197 return MMI->getModule()->getDataLayout();
200 // Do not use the cached DataLayout because some client use it without a Module
201 // (llvm-dsymutil, llvm-dwarfdump).
202 unsigned AsmPrinter::getPointerSize() const { return TM.getPointerSize(); }
204 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
205 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
206 return MF->getSubtarget<MCSubtargetInfo>();
209 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
210 S.EmitInstruction(Inst, getSubtargetInfo());
213 /// getCurrentSection() - Return the current section we are emitting to.
214 const MCSection *AsmPrinter::getCurrentSection() const {
215 return OutStreamer->getCurrentSectionOnly();
218 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
219 AU.setPreservesAll();
220 MachineFunctionPass::getAnalysisUsage(AU);
221 AU.addRequired<MachineModuleInfo>();
222 AU.addRequired<MachineOptimizationRemarkEmitterPass>();
223 AU.addRequired<GCModuleInfo>();
225 AU.addRequired<MachineLoopInfo>();
228 bool AsmPrinter::doInitialization(Module &M) {
229 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
231 // Initialize TargetLoweringObjectFile.
232 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
233 .Initialize(OutContext, TM);
235 OutStreamer->InitSections(false);
237 // Emit the version-min deplyment target directive if needed.
239 // FIXME: If we end up with a collection of these sorts of Darwin-specific
240 // or ELF-specific things, it may make sense to have a platform helper class
241 // that will work with the target helper class. For now keep it here, as the
242 // alternative is duplicated code in each of the target asm printers that
243 // use the directive, where it would need the same conditionalization
245 const Triple &TT = TM.getTargetTriple();
246 // If there is a version specified, Major will be non-zero.
247 if (TT.isOSDarwin() && TT.getOSMajorVersion() != 0) {
248 unsigned Major, Minor, Update;
249 MCVersionMinType VersionType;
250 if (TT.isWatchOS()) {
251 VersionType = MCVM_WatchOSVersionMin;
252 TT.getWatchOSVersion(Major, Minor, Update);
253 } else if (TT.isTvOS()) {
254 VersionType = MCVM_TvOSVersionMin;
255 TT.getiOSVersion(Major, Minor, Update);
256 } else if (TT.isMacOSX()) {
257 VersionType = MCVM_OSXVersionMin;
258 if (!TT.getMacOSXVersion(Major, Minor, Update))
261 VersionType = MCVM_IOSVersionMin;
262 TT.getiOSVersion(Major, Minor, Update);
265 OutStreamer->EmitVersionMin(VersionType, Major, Minor, Update);
268 // Allow the target to emit any magic that it wants at the start of the file.
269 EmitStartOfAsmFile(M);
271 // Very minimal debug info. It is ignored if we emit actual debug info. If we
272 // don't, this at least helps the user find where a global came from.
273 if (MAI->hasSingleParameterDotFile()) {
275 OutStreamer->EmitFileDirective(M.getSourceFileName());
278 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
279 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
281 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
282 MP->beginAssembly(M, *MI, *this);
284 // Emit module-level inline asm if it exists.
285 if (!M.getModuleInlineAsm().empty()) {
286 // We're at the module level. Construct MCSubtarget from the default CPU
287 // and target triple.
288 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
289 TM.getTargetTriple().str(), TM.getTargetCPU(),
290 TM.getTargetFeatureString()));
291 OutStreamer->AddComment("Start of file scope inline assembly");
292 OutStreamer->AddBlankLine();
293 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
294 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
295 OutStreamer->AddComment("End of file scope inline assembly");
296 OutStreamer->AddBlankLine();
299 if (MAI->doesSupportDebugInformation()) {
300 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
301 if (EmitCodeView && (TM.getTargetTriple().isKnownWindowsMSVCEnvironment() ||
302 TM.getTargetTriple().isWindowsItaniumEnvironment())) {
303 Handlers.push_back(HandlerInfo(new CodeViewDebug(this),
304 DbgTimerName, DbgTimerDescription,
305 CodeViewLineTablesGroupName,
306 CodeViewLineTablesGroupDescription));
308 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
309 DD = new DwarfDebug(this, &M);
311 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DbgTimerDescription,
312 DWARFGroupName, DWARFGroupDescription));
316 switch (MAI->getExceptionHandlingType()) {
317 case ExceptionHandling::SjLj:
318 case ExceptionHandling::DwarfCFI:
319 case ExceptionHandling::ARM:
320 isCFIMoveForDebugging = true;
321 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
323 for (auto &F: M.getFunctionList()) {
324 // If the module contains any function with unwind data,
325 // .eh_frame has to be emitted.
326 // Ignore functions that won't get emitted.
327 if (!F.isDeclarationForLinker() && F.needsUnwindTableEntry()) {
328 isCFIMoveForDebugging = false;
334 isCFIMoveForDebugging = false;
338 EHStreamer *ES = nullptr;
339 switch (MAI->getExceptionHandlingType()) {
340 case ExceptionHandling::None:
342 case ExceptionHandling::SjLj:
343 case ExceptionHandling::DwarfCFI:
344 ES = new DwarfCFIException(this);
346 case ExceptionHandling::ARM:
347 ES = new ARMException(this);
349 case ExceptionHandling::WinEH:
350 switch (MAI->getWinEHEncodingType()) {
351 default: llvm_unreachable("unsupported unwinding information encoding");
352 case WinEH::EncodingType::Invalid:
354 case WinEH::EncodingType::X86:
355 case WinEH::EncodingType::Itanium:
356 ES = new WinException(this);
362 Handlers.push_back(HandlerInfo(ES, EHTimerName, EHTimerDescription,
363 DWARFGroupName, DWARFGroupDescription));
367 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
368 if (!MAI.hasWeakDefCanBeHiddenDirective())
371 return canBeOmittedFromSymbolTable(GV);
374 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
375 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
377 case GlobalValue::CommonLinkage:
378 case GlobalValue::LinkOnceAnyLinkage:
379 case GlobalValue::LinkOnceODRLinkage:
380 case GlobalValue::WeakAnyLinkage:
381 case GlobalValue::WeakODRLinkage:
382 if (MAI->hasWeakDefDirective()) {
384 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
386 if (!canBeHidden(GV, *MAI))
387 // .weak_definition _foo
388 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
390 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
391 } else if (MAI->hasLinkOnceDirective()) {
393 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
394 //NOTE: linkonce is handled by the section the symbol was assigned to.
397 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
400 case GlobalValue::ExternalLinkage:
401 // If external, declare as a global symbol: .globl _foo
402 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
404 case GlobalValue::PrivateLinkage:
405 case GlobalValue::InternalLinkage:
407 case GlobalValue::AppendingLinkage:
408 case GlobalValue::AvailableExternallyLinkage:
409 case GlobalValue::ExternalWeakLinkage:
410 llvm_unreachable("Should never emit this");
412 llvm_unreachable("Unknown linkage type!");
415 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
416 const GlobalValue *GV) const {
417 TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
420 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
421 return TM.getSymbol(GV);
424 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
425 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
426 bool IsEmuTLSVar = TM.Options.EmulatedTLS && GV->isThreadLocal();
427 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
428 "No emulated TLS variables in the common section");
430 // Never emit TLS variable xyz in emulated TLS model.
431 // The initialization value is in __emutls_t.xyz instead of xyz.
435 if (GV->hasInitializer()) {
436 // Check to see if this is a special global used by LLVM, if so, emit it.
437 if (EmitSpecialLLVMGlobal(GV))
440 // Skip the emission of global equivalents. The symbol can be emitted later
441 // on by emitGlobalGOTEquivs in case it turns out to be needed.
442 if (GlobalGOTEquivs.count(getSymbol(GV)))
446 // When printing the control variable __emutls_v.*,
447 // we don't need to print the original TLS variable name.
448 GV->printAsOperand(OutStreamer->GetCommentOS(),
449 /*PrintType=*/false, GV->getParent());
450 OutStreamer->GetCommentOS() << '\n';
454 MCSymbol *GVSym = getSymbol(GV);
455 MCSymbol *EmittedSym = GVSym;
457 // getOrCreateEmuTLSControlSym only creates the symbol with name and default
459 // GV's or GVSym's attributes will be used for the EmittedSym.
460 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
462 if (!GV->hasInitializer()) // External globals require no extra code.
465 GVSym->redefineIfPossible();
466 if (GVSym->isDefined() || GVSym->isVariable())
467 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
468 "' is already defined");
470 if (MAI->hasDotTypeDotSizeDirective())
471 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
473 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
475 const DataLayout &DL = GV->getParent()->getDataLayout();
476 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
478 // If the alignment is specified, we *must* obey it. Overaligning a global
479 // with a specified alignment is a prompt way to break globals emitted to
480 // sections and expected to be contiguous (e.g. ObjC metadata).
481 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
483 for (const HandlerInfo &HI : Handlers) {
484 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
485 HI.TimerGroupName, HI.TimerGroupDescription,
486 TimePassesIsEnabled);
487 HI.Handler->setSymbolSize(GVSym, Size);
490 // Handle common symbols
491 if (GVKind.isCommon()) {
492 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
493 unsigned Align = 1 << AlignLog;
494 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
498 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
502 // Determine to which section this global should be emitted.
503 MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
505 // If we have a bss global going to a section that supports the
506 // zerofill directive, do so here.
507 if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
508 TheSection->isVirtualSection()) {
510 Size = 1; // zerofill of 0 bytes is undefined.
511 unsigned Align = 1 << AlignLog;
512 EmitLinkage(GV, GVSym);
513 // .zerofill __DATA, __bss, _foo, 400, 5
514 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
518 // If this is a BSS local symbol and we are emitting in the BSS
519 // section use .lcomm/.comm directive.
520 if (GVKind.isBSSLocal() &&
521 getObjFileLowering().getBSSSection() == TheSection) {
523 Size = 1; // .comm Foo, 0 is undefined, avoid it.
524 unsigned Align = 1 << AlignLog;
526 // Use .lcomm only if it supports user-specified alignment.
527 // Otherwise, while it would still be correct to use .lcomm in some
528 // cases (e.g. when Align == 1), the external assembler might enfore
529 // some -unknown- default alignment behavior, which could cause
530 // spurious differences between external and integrated assembler.
531 // Prefer to simply fall back to .local / .comm in this case.
532 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
534 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
538 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
542 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
544 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
548 // Handle thread local data for mach-o which requires us to output an
549 // additional structure of data and mangle the original symbol so that we
550 // can reference it later.
552 // TODO: This should become an "emit thread local global" method on TLOF.
553 // All of this macho specific stuff should be sunk down into TLOFMachO and
554 // stuff like "TLSExtraDataSection" should no longer be part of the parent
555 // TLOF class. This will also make it more obvious that stuff like
556 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
558 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
559 // Emit the .tbss symbol
561 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
563 if (GVKind.isThreadBSS()) {
564 TheSection = getObjFileLowering().getTLSBSSSection();
565 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
566 } else if (GVKind.isThreadData()) {
567 OutStreamer->SwitchSection(TheSection);
569 EmitAlignment(AlignLog, GV);
570 OutStreamer->EmitLabel(MangSym);
572 EmitGlobalConstant(GV->getParent()->getDataLayout(),
573 GV->getInitializer());
576 OutStreamer->AddBlankLine();
578 // Emit the variable struct for the runtime.
579 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
581 OutStreamer->SwitchSection(TLVSect);
582 // Emit the linkage here.
583 EmitLinkage(GV, GVSym);
584 OutStreamer->EmitLabel(GVSym);
586 // Three pointers in size:
587 // - __tlv_bootstrap - used to make sure support exists
588 // - spare pointer, used when mapped by the runtime
589 // - pointer to mangled symbol above with initializer
590 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
591 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
593 OutStreamer->EmitIntValue(0, PtrSize);
594 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
596 OutStreamer->AddBlankLine();
600 MCSymbol *EmittedInitSym = GVSym;
602 OutStreamer->SwitchSection(TheSection);
604 EmitLinkage(GV, EmittedInitSym);
605 EmitAlignment(AlignLog, GV);
607 OutStreamer->EmitLabel(EmittedInitSym);
609 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
611 if (MAI->hasDotTypeDotSizeDirective())
613 OutStreamer->emitELFSize(EmittedInitSym,
614 MCConstantExpr::create(Size, OutContext));
616 OutStreamer->AddBlankLine();
619 /// Emit the directive and value for debug thread local expression
621 /// \p Value - The value to emit.
622 /// \p Size - The size of the integer (in bytes) to emit.
623 void AsmPrinter::EmitDebugThreadLocal(const MCExpr *Value,
624 unsigned Size) const {
625 OutStreamer->EmitValue(Value, Size);
628 /// EmitFunctionHeader - This method emits the header for the current
630 void AsmPrinter::EmitFunctionHeader() {
631 const Function *F = MF->getFunction();
634 OutStreamer->GetCommentOS() << "-- Begin function " << F->getName() << '\n';
636 // Print out constants referenced by the function
639 // Print the 'header' of function.
640 OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(F, TM));
641 EmitVisibility(CurrentFnSym, F->getVisibility());
643 EmitLinkage(F, CurrentFnSym);
644 if (MAI->hasFunctionAlignment())
645 EmitAlignment(MF->getAlignment(), F);
647 if (MAI->hasDotTypeDotSizeDirective())
648 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
651 F->printAsOperand(OutStreamer->GetCommentOS(),
652 /*PrintType=*/false, F->getParent());
653 OutStreamer->GetCommentOS() << '\n';
656 // Emit the prefix data.
657 if (F->hasPrefixData()) {
658 if (MAI->hasSubsectionsViaSymbols()) {
659 // Preserving prefix data on platforms which use subsections-via-symbols
660 // is a bit tricky. Here we introduce a symbol for the prefix data
661 // and use the .alt_entry attribute to mark the function's real entry point
662 // as an alternative entry point to the prefix-data symbol.
663 MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
664 OutStreamer->EmitLabel(PrefixSym);
666 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
668 // Emit an .alt_entry directive for the actual function symbol.
669 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
671 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
675 // Emit the CurrentFnSym. This is a virtual function to allow targets to
676 // do their wild and crazy things as required.
677 EmitFunctionEntryLabel();
679 // If the function had address-taken blocks that got deleted, then we have
680 // references to the dangling symbols. Emit them at the start of the function
681 // so that we don't get references to undefined symbols.
682 std::vector<MCSymbol*> DeadBlockSyms;
683 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
684 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
685 OutStreamer->AddComment("Address taken block that was later removed");
686 OutStreamer->EmitLabel(DeadBlockSyms[i]);
689 if (CurrentFnBegin) {
690 if (MAI->useAssignmentForEHBegin()) {
691 MCSymbol *CurPos = OutContext.createTempSymbol();
692 OutStreamer->EmitLabel(CurPos);
693 OutStreamer->EmitAssignment(CurrentFnBegin,
694 MCSymbolRefExpr::create(CurPos, OutContext));
696 OutStreamer->EmitLabel(CurrentFnBegin);
700 // Emit pre-function debug and/or EH information.
701 for (const HandlerInfo &HI : Handlers) {
702 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
703 HI.TimerGroupDescription, TimePassesIsEnabled);
704 HI.Handler->beginFunction(MF);
707 // Emit the prologue data.
708 if (F->hasPrologueData())
709 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrologueData());
712 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
713 /// function. This can be overridden by targets as required to do custom stuff.
714 void AsmPrinter::EmitFunctionEntryLabel() {
715 CurrentFnSym->redefineIfPossible();
717 // The function label could have already been emitted if two symbols end up
718 // conflicting due to asm renaming. Detect this and emit an error.
719 if (CurrentFnSym->isVariable())
720 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
721 "' is a protected alias");
722 if (CurrentFnSym->isDefined())
723 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
724 "' label emitted multiple times to assembly file");
726 return OutStreamer->EmitLabel(CurrentFnSym);
729 /// emitComments - Pretty-print comments for instructions.
730 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS,
732 const MachineFunction *MF = MI.getParent()->getParent();
733 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
735 // Check for spills and reloads
738 const MachineFrameInfo &MFI = MF->getFrameInfo();
739 bool Commented = false;
741 // We assume a single instruction only has a spill or reload, not
743 const MachineMemOperand *MMO;
744 if (TII->isLoadFromStackSlotPostFE(MI, FI)) {
745 if (MFI.isSpillSlotObjectIndex(FI)) {
746 MMO = *MI.memoperands_begin();
747 CommentOS << MMO->getSize() << "-byte Reload";
750 } else if (TII->hasLoadFromStackSlot(MI, MMO, FI)) {
751 if (MFI.isSpillSlotObjectIndex(FI)) {
752 CommentOS << MMO->getSize() << "-byte Folded Reload";
755 } else if (TII->isStoreToStackSlotPostFE(MI, FI)) {
756 if (MFI.isSpillSlotObjectIndex(FI)) {
757 MMO = *MI.memoperands_begin();
758 CommentOS << MMO->getSize() << "-byte Spill";
761 } else if (TII->hasStoreToStackSlot(MI, MMO, FI)) {
762 if (MFI.isSpillSlotObjectIndex(FI)) {
763 CommentOS << MMO->getSize() << "-byte Folded Spill";
768 // Check for spill-induced copies
769 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) {
771 CommentOS << " Reload Reuse";
774 if (Commented && AP->EnablePrintSchedInfo)
775 // If any comment was added above and we need sched info comment then
776 // add this new comment just after the above comment w/o "\n" between them.
777 CommentOS << " " << MF->getSubtarget().getSchedInfoStr(MI) << "\n";
782 /// emitImplicitDef - This method emits the specified machine instruction
783 /// that is an implicit def.
784 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
785 unsigned RegNo = MI->getOperand(0).getReg();
787 SmallString<128> Str;
788 raw_svector_ostream OS(Str);
789 OS << "implicit-def: "
790 << PrintReg(RegNo, MF->getSubtarget().getRegisterInfo());
792 OutStreamer->AddComment(OS.str());
793 OutStreamer->AddBlankLine();
796 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
798 raw_string_ostream OS(Str);
800 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
801 const MachineOperand &Op = MI->getOperand(i);
802 assert(Op.isReg() && "KILL instruction must have only register operands");
804 << PrintReg(Op.getReg(),
805 AP.MF->getSubtarget().getRegisterInfo())
806 << (Op.isDef() ? "<def>" : "<kill>");
808 AP.OutStreamer->AddComment(OS.str());
809 AP.OutStreamer->AddBlankLine();
812 /// emitDebugValueComment - This method handles the target-independent form
813 /// of DBG_VALUE, returning true if it was able to do so. A false return
814 /// means the target will need to handle MI in EmitInstruction.
815 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
816 // This code handles only the 4-operand target-independent form.
817 if (MI->getNumOperands() != 4)
820 SmallString<128> Str;
821 raw_svector_ostream OS(Str);
822 OS << "DEBUG_VALUE: ";
824 const DILocalVariable *V = MI->getDebugVariable();
825 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
826 StringRef Name = SP->getName();
833 // The second operand is only an offset if it's an immediate.
834 bool MemLoc = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
835 int64_t Offset = MemLoc ? MI->getOperand(1).getImm() : 0;
836 const DIExpression *Expr = MI->getDebugExpression();
837 if (Expr->getNumElements()) {
839 bool NeedSep = false;
840 for (auto Op : Expr->expr_ops()) {
845 OS << dwarf::OperationEncodingString(Op.getOp());
846 for (unsigned I = 0; I < Op.getNumArgs(); ++I)
847 OS << ' ' << Op.getArg(I);
852 // Register or immediate value. Register 0 means undef.
853 if (MI->getOperand(0).isFPImm()) {
854 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
855 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
856 OS << (double)APF.convertToFloat();
857 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
858 OS << APF.convertToDouble();
860 // There is no good way to print long double. Convert a copy to
861 // double. Ah well, it's only a comment.
863 APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
865 OS << "(long double) " << APF.convertToDouble();
867 } else if (MI->getOperand(0).isImm()) {
868 OS << MI->getOperand(0).getImm();
869 } else if (MI->getOperand(0).isCImm()) {
870 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
873 if (MI->getOperand(0).isReg()) {
874 Reg = MI->getOperand(0).getReg();
876 assert(MI->getOperand(0).isFI() && "Unknown operand type");
877 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
878 Offset += TFI->getFrameIndexReference(*AP.MF,
879 MI->getOperand(0).getIndex(), Reg);
883 // Suppress offset, it is not meaningful here.
885 // NOTE: Want this comment at start of line, don't emit with AddComment.
886 AP.OutStreamer->emitRawComment(OS.str());
891 OS << PrintReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
895 OS << '+' << Offset << ']';
897 // NOTE: Want this comment at start of line, don't emit with AddComment.
898 AP.OutStreamer->emitRawComment(OS.str());
902 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
903 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
904 MF->getFunction()->needsUnwindTableEntry())
907 if (MMI->hasDebugInfo())
913 bool AsmPrinter::needsSEHMoves() {
914 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
917 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
918 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
919 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
920 ExceptionHandlingType != ExceptionHandling::ARM)
923 if (needsCFIMoves() == CFI_M_None)
926 // If there is no "real" instruction following this CFI instruction, skip
927 // emitting it; it would be beyond the end of the function's FDE range.
928 auto *MBB = MI.getParent();
929 auto I = std::next(MI.getIterator());
930 while (I != MBB->end() && I->isTransient())
932 if (I == MBB->instr_end() &&
933 MBB->getReverseIterator() == MBB->getParent()->rbegin())
936 const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions();
937 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
938 const MCCFIInstruction &CFI = Instrs[CFIIndex];
939 emitCFIInstruction(CFI);
942 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
943 // The operands are the MCSymbol and the frame offset of the allocation.
944 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
945 int FrameOffset = MI.getOperand(1).getImm();
947 // Emit a symbol assignment.
948 OutStreamer->EmitAssignment(FrameAllocSym,
949 MCConstantExpr::create(FrameOffset, OutContext));
952 static bool needFuncLabelsForEHOrDebugInfo(const MachineFunction &MF,
953 MachineModuleInfo *MMI) {
954 if (!MF.getLandingPads().empty() || MF.hasEHFunclets() || MMI->hasDebugInfo())
957 // We might emit an EH table that uses function begin and end labels even if
958 // we don't have any landingpads.
959 if (!MF.getFunction()->hasPersonalityFn())
961 return !isNoOpWithoutInvoke(
962 classifyEHPersonality(MF.getFunction()->getPersonalityFn()));
965 /// EmitFunctionBody - This method emits the body and trailer for a
967 void AsmPrinter::EmitFunctionBody() {
968 EmitFunctionHeader();
970 // Emit target-specific gunk before the function body.
971 EmitFunctionBodyStart();
973 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
975 // Print out code for the function.
976 bool HasAnyRealCode = false;
977 int NumInstsInFunction = 0;
978 for (auto &MBB : *MF) {
979 // Print a label for the basic block.
980 EmitBasicBlockStart(MBB);
981 for (auto &MI : MBB) {
983 // Print the assembly for the instruction.
984 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
985 !MI.isDebugValue()) {
986 HasAnyRealCode = true;
987 ++NumInstsInFunction;
990 if (ShouldPrintDebugScopes) {
991 for (const HandlerInfo &HI : Handlers) {
992 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
993 HI.TimerGroupName, HI.TimerGroupDescription,
994 TimePassesIsEnabled);
995 HI.Handler->beginInstruction(&MI);
1000 emitComments(MI, OutStreamer->GetCommentOS(), this);
1002 switch (MI.getOpcode()) {
1003 case TargetOpcode::CFI_INSTRUCTION:
1004 emitCFIInstruction(MI);
1007 case TargetOpcode::LOCAL_ESCAPE:
1011 case TargetOpcode::EH_LABEL:
1012 case TargetOpcode::GC_LABEL:
1013 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
1015 case TargetOpcode::INLINEASM:
1018 case TargetOpcode::DBG_VALUE:
1020 if (!emitDebugValueComment(&MI, *this))
1021 EmitInstruction(&MI);
1024 case TargetOpcode::IMPLICIT_DEF:
1025 if (isVerbose()) emitImplicitDef(&MI);
1027 case TargetOpcode::KILL:
1028 if (isVerbose()) emitKill(&MI, *this);
1031 EmitInstruction(&MI);
1035 if (ShouldPrintDebugScopes) {
1036 for (const HandlerInfo &HI : Handlers) {
1037 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1038 HI.TimerGroupName, HI.TimerGroupDescription,
1039 TimePassesIsEnabled);
1040 HI.Handler->endInstruction();
1045 EmitBasicBlockEnd(MBB);
1048 EmittedInsts += NumInstsInFunction;
1049 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
1050 MF->getFunction()->getSubprogram(),
1052 R << ore::NV("NumInstructions", NumInstsInFunction)
1053 << " instructions in function";
1056 // If the function is empty and the object file uses .subsections_via_symbols,
1057 // then we need to emit *something* to the function body to prevent the
1058 // labels from collapsing together. Just emit a noop.
1059 // Similarly, don't emit empty functions on Windows either. It can lead to
1060 // duplicate entries (two functions with the same RVA) in the Guard CF Table
1061 // after linking, causing the kernel not to load the binary:
1062 // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
1063 // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
1064 const Triple &TT = TM.getTargetTriple();
1065 if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() ||
1066 (TT.isOSWindows() && TT.isOSBinFormatCOFF()))) {
1068 MF->getSubtarget().getInstrInfo()->getNoop(Noop);
1070 // Targets can opt-out of emitting the noop here by leaving the opcode
1072 if (Noop.getOpcode()) {
1073 OutStreamer->AddComment("avoids zero-length function");
1074 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
1078 const Function *F = MF->getFunction();
1079 for (const auto &BB : *F) {
1080 if (!BB.hasAddressTaken())
1082 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
1083 if (Sym->isDefined())
1085 OutStreamer->AddComment("Address of block that was removed by CodeGen");
1086 OutStreamer->EmitLabel(Sym);
1089 // Emit target-specific gunk after the function body.
1090 EmitFunctionBodyEnd();
1092 if (needFuncLabelsForEHOrDebugInfo(*MF, MMI) ||
1093 MAI->hasDotTypeDotSizeDirective()) {
1094 // Create a symbol for the end of function.
1095 CurrentFnEnd = createTempSymbol("func_end");
1096 OutStreamer->EmitLabel(CurrentFnEnd);
1099 // If the target wants a .size directive for the size of the function, emit
1101 if (MAI->hasDotTypeDotSizeDirective()) {
1102 // We can get the size as difference between the function label and the
1104 const MCExpr *SizeExp = MCBinaryExpr::createSub(
1105 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1106 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1107 OutStreamer->emitELFSize(CurrentFnSym, SizeExp);
1110 for (const HandlerInfo &HI : Handlers) {
1111 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1112 HI.TimerGroupDescription, TimePassesIsEnabled);
1113 HI.Handler->markFunctionEnd();
1116 // Print out jump tables referenced by the function.
1117 EmitJumpTableInfo();
1119 // Emit post-function debug and/or EH information.
1120 for (const HandlerInfo &HI : Handlers) {
1121 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1122 HI.TimerGroupDescription, TimePassesIsEnabled);
1123 HI.Handler->endFunction(MF);
1127 OutStreamer->GetCommentOS() << "-- End function\n";
1129 OutStreamer->AddBlankLine();
1132 /// \brief Compute the number of Global Variables that uses a Constant.
1133 static unsigned getNumGlobalVariableUses(const Constant *C) {
1137 if (isa<GlobalVariable>(C))
1140 unsigned NumUses = 0;
1141 for (auto *CU : C->users())
1142 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1147 /// \brief Only consider global GOT equivalents if at least one user is a
1148 /// cstexpr inside an initializer of another global variables. Also, don't
1149 /// handle cstexpr inside instructions. During global variable emission,
1150 /// candidates are skipped and are emitted later in case at least one cstexpr
1151 /// isn't replaced by a PC relative GOT entry access.
1152 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1153 unsigned &NumGOTEquivUsers) {
1154 // Global GOT equivalents are unnamed private globals with a constant
1155 // pointer initializer to another global symbol. They must point to a
1156 // GlobalVariable or Function, i.e., as GlobalValue.
1157 if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
1158 !GV->isConstant() || !GV->isDiscardableIfUnused() ||
1159 !dyn_cast<GlobalValue>(GV->getOperand(0)))
1162 // To be a got equivalent, at least one of its users need to be a constant
1163 // expression used by another global variable.
1164 for (auto *U : GV->users())
1165 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1167 return NumGOTEquivUsers > 0;
1170 /// \brief Unnamed constant global variables solely contaning a pointer to
1171 /// another globals variable is equivalent to a GOT table entry; it contains the
1172 /// the address of another symbol. Optimize it and replace accesses to these
1173 /// "GOT equivalents" by using the GOT entry for the final global instead.
1174 /// Compute GOT equivalent candidates among all global variables to avoid
1175 /// emitting them if possible later on, after it use is replaced by a GOT entry
1177 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1178 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1181 for (const auto &G : M.globals()) {
1182 unsigned NumGOTEquivUsers = 0;
1183 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1186 const MCSymbol *GOTEquivSym = getSymbol(&G);
1187 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1191 /// \brief Constant expressions using GOT equivalent globals may not be eligible
1192 /// for PC relative GOT entry conversion, in such cases we need to emit such
1193 /// globals we previously omitted in EmitGlobalVariable.
1194 void AsmPrinter::emitGlobalGOTEquivs() {
1195 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1198 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1199 for (auto &I : GlobalGOTEquivs) {
1200 const GlobalVariable *GV = I.second.first;
1201 unsigned Cnt = I.second.second;
1203 FailedCandidates.push_back(GV);
1205 GlobalGOTEquivs.clear();
1207 for (auto *GV : FailedCandidates)
1208 EmitGlobalVariable(GV);
1211 void AsmPrinter::emitGlobalIndirectSymbol(Module &M,
1212 const GlobalIndirectSymbol& GIS) {
1213 MCSymbol *Name = getSymbol(&GIS);
1215 if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective())
1216 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1217 else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage())
1218 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1220 assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage");
1222 // Set the symbol type to function if the alias has a function type.
1223 // This affects codegen when the aliasee is not a function.
1224 if (GIS.getType()->getPointerElementType()->isFunctionTy()) {
1225 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
1226 if (isa<GlobalIFunc>(GIS))
1227 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
1230 EmitVisibility(Name, GIS.getVisibility());
1232 const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol());
1234 if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
1235 OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry);
1237 // Emit the directives as assignments aka .set:
1238 OutStreamer->EmitAssignment(Name, Expr);
1240 if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) {
1241 // If the aliasee does not correspond to a symbol in the output, i.e. the
1242 // alias is not of an object or the aliased object is private, then set the
1243 // size of the alias symbol from the type of the alias. We don't do this in
1244 // other situations as the alias and aliasee having differing types but same
1245 // size may be intentional.
1246 const GlobalObject *BaseObject = GA->getBaseObject();
1247 if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() &&
1248 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1249 const DataLayout &DL = M.getDataLayout();
1250 uint64_t Size = DL.getTypeAllocSize(GA->getValueType());
1251 OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
1256 bool AsmPrinter::doFinalization(Module &M) {
1257 // Set the MachineFunction to nullptr so that we can catch attempted
1258 // accesses to MF specific features at the module level and so that
1259 // we can conditionalize accesses based on whether or not it is nullptr.
1262 // Gather all GOT equivalent globals in the module. We really need two
1263 // passes over the globals: one to compute and another to avoid its emission
1264 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1265 // where the got equivalent shows up before its use.
1266 computeGlobalGOTEquivs(M);
1268 // Emit global variables.
1269 for (const auto &G : M.globals())
1270 EmitGlobalVariable(&G);
1272 // Emit remaining GOT equivalent globals.
1273 emitGlobalGOTEquivs();
1275 // Emit visibility info for declarations
1276 for (const Function &F : M) {
1277 if (!F.isDeclarationForLinker())
1279 GlobalValue::VisibilityTypes V = F.getVisibility();
1280 if (V == GlobalValue::DefaultVisibility)
1283 MCSymbol *Name = getSymbol(&F);
1284 EmitVisibility(Name, V, false);
1287 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1289 // Emit module flags.
1290 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1291 M.getModuleFlagsMetadata(ModuleFlags);
1292 if (!ModuleFlags.empty())
1293 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, TM);
1295 if (TM.getTargetTriple().isOSBinFormatELF()) {
1296 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1298 // Output stubs for external and common global variables.
1299 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1300 if (!Stubs.empty()) {
1301 OutStreamer->SwitchSection(TLOF.getDataSection());
1302 const DataLayout &DL = M.getDataLayout();
1304 for (const auto &Stub : Stubs) {
1305 OutStreamer->EmitLabel(Stub.first);
1306 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1307 DL.getPointerSize());
1312 // Finalize debug and EH information.
1313 for (const HandlerInfo &HI : Handlers) {
1314 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1315 HI.TimerGroupDescription, TimePassesIsEnabled);
1316 HI.Handler->endModule();
1322 // If the target wants to know about weak references, print them all.
1323 if (MAI->getWeakRefDirective()) {
1324 // FIXME: This is not lazy, it would be nice to only print weak references
1325 // to stuff that is actually used. Note that doing so would require targets
1326 // to notice uses in operands (due to constant exprs etc). This should
1327 // happen with the MC stuff eventually.
1329 // Print out module-level global objects here.
1330 for (const auto &GO : M.global_objects()) {
1331 if (!GO.hasExternalWeakLinkage())
1333 OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
1337 OutStreamer->AddBlankLine();
1339 // Print aliases in topological order, that is, for each alias a = b,
1340 // b must be printed before a.
1341 // This is because on some targets (e.g. PowerPC) linker expects aliases in
1342 // such an order to generate correct TOC information.
1343 SmallVector<const GlobalAlias *, 16> AliasStack;
1344 SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
1345 for (const auto &Alias : M.aliases()) {
1346 for (const GlobalAlias *Cur = &Alias; Cur;
1347 Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
1348 if (!AliasVisited.insert(Cur).second)
1350 AliasStack.push_back(Cur);
1352 for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
1353 emitGlobalIndirectSymbol(M, *AncestorAlias);
1356 for (const auto &IFunc : M.ifuncs())
1357 emitGlobalIndirectSymbol(M, IFunc);
1359 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1360 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1361 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1362 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1363 MP->finishAssembly(M, *MI, *this);
1365 // Emit llvm.ident metadata in an '.ident' directive.
1366 EmitModuleIdents(M);
1368 // Emit __morestack address if needed for indirect calls.
1369 if (MMI->usesMorestackAddr()) {
1371 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1372 getDataLayout(), SectionKind::getReadOnly(),
1373 /*C=*/nullptr, Align);
1374 OutStreamer->SwitchSection(ReadOnlySection);
1376 MCSymbol *AddrSymbol =
1377 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1378 OutStreamer->EmitLabel(AddrSymbol);
1380 unsigned PtrSize = MAI->getCodePointerSize();
1381 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1385 // If we don't have any trampolines, then we don't require stack memory
1386 // to be executable. Some targets have a directive to declare this.
1387 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1388 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1389 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1390 OutStreamer->SwitchSection(S);
1392 // Allow the target to emit any magic that it wants at the end of the file,
1393 // after everything else has gone out.
1394 EmitEndOfAsmFile(M);
1398 OutStreamer->Finish();
1399 OutStreamer->reset();
1404 MCSymbol *AsmPrinter::getCurExceptionSym() {
1405 if (!CurExceptionSym)
1406 CurExceptionSym = createTempSymbol("exception");
1407 return CurExceptionSym;
1410 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1412 // Get the function symbol.
1413 CurrentFnSym = getSymbol(MF.getFunction());
1414 CurrentFnSymForSize = CurrentFnSym;
1415 CurrentFnBegin = nullptr;
1416 CurExceptionSym = nullptr;
1417 bool NeedsLocalForSize = MAI->needsLocalForSize();
1418 if (needFuncLabelsForEHOrDebugInfo(MF, MMI) || NeedsLocalForSize) {
1419 CurrentFnBegin = createTempSymbol("func_begin");
1420 if (NeedsLocalForSize)
1421 CurrentFnSymForSize = CurrentFnBegin;
1424 ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
1426 LI = &getAnalysis<MachineLoopInfo>();
1428 const TargetSubtargetInfo &STI = MF.getSubtarget();
1429 EnablePrintSchedInfo = PrintSchedule.getNumOccurrences()
1431 : STI.supportPrintSchedInfo();
1436 // Keep track the alignment, constpool entries per Section.
1440 SmallVector<unsigned, 4> CPEs;
1442 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1445 } // end anonymous namespace
1447 /// EmitConstantPool - Print to the current output stream assembly
1448 /// representations of the constants in the constant pool MCP. This is
1449 /// used to print out constants which have been "spilled to memory" by
1450 /// the code generator.
1452 void AsmPrinter::EmitConstantPool() {
1453 const MachineConstantPool *MCP = MF->getConstantPool();
1454 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1455 if (CP.empty()) return;
1457 // Calculate sections for constant pool entries. We collect entries to go into
1458 // the same section together to reduce amount of section switch statements.
1459 SmallVector<SectionCPs, 4> CPSections;
1460 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1461 const MachineConstantPoolEntry &CPE = CP[i];
1462 unsigned Align = CPE.getAlignment();
1464 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1466 const Constant *C = nullptr;
1467 if (!CPE.isMachineConstantPoolEntry())
1468 C = CPE.Val.ConstVal;
1470 MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
1473 // The number of sections are small, just do a linear search from the
1474 // last section to the first.
1476 unsigned SecIdx = CPSections.size();
1477 while (SecIdx != 0) {
1478 if (CPSections[--SecIdx].S == S) {
1484 SecIdx = CPSections.size();
1485 CPSections.push_back(SectionCPs(S, Align));
1488 if (Align > CPSections[SecIdx].Alignment)
1489 CPSections[SecIdx].Alignment = Align;
1490 CPSections[SecIdx].CPEs.push_back(i);
1493 // Now print stuff into the calculated sections.
1494 const MCSection *CurSection = nullptr;
1495 unsigned Offset = 0;
1496 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1497 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1498 unsigned CPI = CPSections[i].CPEs[j];
1499 MCSymbol *Sym = GetCPISymbol(CPI);
1500 if (!Sym->isUndefined())
1503 if (CurSection != CPSections[i].S) {
1504 OutStreamer->SwitchSection(CPSections[i].S);
1505 EmitAlignment(Log2_32(CPSections[i].Alignment));
1506 CurSection = CPSections[i].S;
1510 MachineConstantPoolEntry CPE = CP[CPI];
1512 // Emit inter-object padding for alignment.
1513 unsigned AlignMask = CPE.getAlignment() - 1;
1514 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1515 OutStreamer->EmitZeros(NewOffset - Offset);
1517 Type *Ty = CPE.getType();
1518 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1520 OutStreamer->EmitLabel(Sym);
1521 if (CPE.isMachineConstantPoolEntry())
1522 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1524 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1529 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1530 /// by the current function to the current output stream.
1532 void AsmPrinter::EmitJumpTableInfo() {
1533 const DataLayout &DL = MF->getDataLayout();
1534 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1536 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1537 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1538 if (JT.empty()) return;
1540 // Pick the directive to use to print the jump table entries, and switch to
1541 // the appropriate section.
1542 const Function *F = MF->getFunction();
1543 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1544 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1545 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1547 if (JTInDiffSection) {
1548 // Drop it in the readonly section.
1549 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(*F, TM);
1550 OutStreamer->SwitchSection(ReadOnlySection);
1553 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1555 // Jump tables in code sections are marked with a data_region directive
1556 // where that's supported.
1557 if (!JTInDiffSection)
1558 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1560 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1561 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1563 // If this jump table was deleted, ignore it.
1564 if (JTBBs.empty()) continue;
1566 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1567 /// emit a .set directive for each unique entry.
1568 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1569 MAI->doesSetDirectiveSuppressReloc()) {
1570 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1571 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1572 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1573 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1574 const MachineBasicBlock *MBB = JTBBs[ii];
1575 if (!EmittedSets.insert(MBB).second)
1578 // .set LJTSet, LBB32-base
1580 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1581 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1582 MCBinaryExpr::createSub(LHS, Base,
1587 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1588 // before each jump table. The first label is never referenced, but tells
1589 // the assembler and linker the extents of the jump table object. The
1590 // second label is actually referenced by the code.
1591 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1592 // FIXME: This doesn't have to have any specific name, just any randomly
1593 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1594 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1596 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1598 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1599 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1601 if (!JTInDiffSection)
1602 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1605 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1607 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1608 const MachineBasicBlock *MBB,
1609 unsigned UID) const {
1610 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1611 const MCExpr *Value = nullptr;
1612 switch (MJTI->getEntryKind()) {
1613 case MachineJumpTableInfo::EK_Inline:
1614 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1615 case MachineJumpTableInfo::EK_Custom32:
1616 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1617 MJTI, MBB, UID, OutContext);
1619 case MachineJumpTableInfo::EK_BlockAddress:
1620 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1622 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1624 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1625 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1626 // with a relocation as gp-relative, e.g.:
1628 MCSymbol *MBBSym = MBB->getSymbol();
1629 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1633 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1634 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1635 // with a relocation as gp-relative, e.g.:
1637 MCSymbol *MBBSym = MBB->getSymbol();
1638 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1642 case MachineJumpTableInfo::EK_LabelDifference32: {
1643 // Each entry is the address of the block minus the address of the jump
1644 // table. This is used for PIC jump tables where gprel32 is not supported.
1646 // .word LBB123 - LJTI1_2
1647 // If the .set directive avoids relocations, this is emitted as:
1648 // .set L4_5_set_123, LBB123 - LJTI1_2
1649 // .word L4_5_set_123
1650 if (MAI->doesSetDirectiveSuppressReloc()) {
1651 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1655 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1656 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1657 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1658 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1663 assert(Value && "Unknown entry kind!");
1665 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1666 OutStreamer->EmitValue(Value, EntrySize);
1669 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1670 /// special global used by LLVM. If so, emit it and return true, otherwise
1671 /// do nothing and return false.
1672 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1673 if (GV->getName() == "llvm.used") {
1674 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1675 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1679 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1680 if (GV->getSection() == "llvm.metadata" ||
1681 GV->hasAvailableExternallyLinkage())
1684 if (!GV->hasAppendingLinkage()) return false;
1686 assert(GV->hasInitializer() && "Not a special LLVM global!");
1688 if (GV->getName() == "llvm.global_ctors") {
1689 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1695 if (GV->getName() == "llvm.global_dtors") {
1696 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1697 /* isCtor */ false);
1702 report_fatal_error("unknown special variable");
1705 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1706 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1707 /// is true, as being used with this directive.
1708 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1709 // Should be an array of 'i8*'.
1710 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1711 const GlobalValue *GV =
1712 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1714 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1722 Constant *Func = nullptr;
1723 GlobalValue *ComdatKey = nullptr;
1725 Structor() = default;
1728 } // end anonymous namespace
1730 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1732 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1734 // Should be an array of '{ int, void ()* }' structs. The first value is the
1736 if (!isa<ConstantArray>(List)) return;
1738 // Sanity check the structors list.
1739 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1740 if (!InitList) return; // Not an array!
1741 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1742 // FIXME: Only allow the 3-field form in LLVM 4.0.
1743 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1744 return; // Not an array of two or three elements!
1745 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1746 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1747 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1748 return; // Not (int, ptr, ptr).
1750 // Gather the structors in a form that's convenient for sorting by priority.
1751 SmallVector<Structor, 8> Structors;
1752 for (Value *O : InitList->operands()) {
1753 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1754 if (!CS) continue; // Malformed.
1755 if (CS->getOperand(1)->isNullValue())
1756 break; // Found a null terminator, skip the rest.
1757 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1758 if (!Priority) continue; // Malformed.
1759 Structors.push_back(Structor());
1760 Structor &S = Structors.back();
1761 S.Priority = Priority->getLimitedValue(65535);
1762 S.Func = CS->getOperand(1);
1763 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1765 dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1768 // Emit the function pointers in the target-specific order
1769 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1770 std::stable_sort(Structors.begin(), Structors.end(),
1771 [](const Structor &L,
1772 const Structor &R) { return L.Priority < R.Priority; });
1773 for (Structor &S : Structors) {
1774 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1775 const MCSymbol *KeySym = nullptr;
1776 if (GlobalValue *GV = S.ComdatKey) {
1777 if (GV->isDeclarationForLinker())
1778 // If the associated variable is not defined in this module
1779 // (it might be available_externally, or have been an
1780 // available_externally definition that was dropped by the
1781 // EliminateAvailableExternally pass), some other TU
1782 // will provide its dynamic initializer.
1785 KeySym = getSymbol(GV);
1787 MCSection *OutputSection =
1788 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1789 : Obj.getStaticDtorSection(S.Priority, KeySym));
1790 OutStreamer->SwitchSection(OutputSection);
1791 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1792 EmitAlignment(Align);
1793 EmitXXStructor(DL, S.Func);
1797 void AsmPrinter::EmitModuleIdents(Module &M) {
1798 if (!MAI->hasIdentDirective())
1801 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1802 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1803 const MDNode *N = NMD->getOperand(i);
1804 assert(N->getNumOperands() == 1 &&
1805 "llvm.ident metadata entry can have only one operand");
1806 const MDString *S = cast<MDString>(N->getOperand(0));
1807 OutStreamer->EmitIdent(S->getString());
1812 //===--------------------------------------------------------------------===//
1813 // Emission and print routines
1816 /// EmitInt8 - Emit a byte directive and value.
1818 void AsmPrinter::EmitInt8(int Value) const {
1819 OutStreamer->EmitIntValue(Value, 1);
1822 /// EmitInt16 - Emit a short directive and value.
1824 void AsmPrinter::EmitInt16(int Value) const {
1825 OutStreamer->EmitIntValue(Value, 2);
1828 /// EmitInt32 - Emit a long directive and value.
1830 void AsmPrinter::EmitInt32(int Value) const {
1831 OutStreamer->EmitIntValue(Value, 4);
1834 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1835 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1836 /// .set if it avoids relocations.
1837 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1838 unsigned Size) const {
1839 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
1842 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1843 /// where the size in bytes of the directive is specified by Size and Label
1844 /// specifies the label. This implicitly uses .set if it is available.
1845 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1847 bool IsSectionRelative) const {
1848 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1849 OutStreamer->EmitCOFFSecRel32(Label, Offset);
1851 OutStreamer->EmitZeros(Size - 4);
1855 // Emit Label+Offset (or just Label if Offset is zero)
1856 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
1858 Expr = MCBinaryExpr::createAdd(
1859 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
1861 OutStreamer->EmitValue(Expr, Size);
1864 //===----------------------------------------------------------------------===//
1866 // EmitAlignment - Emit an alignment directive to the specified power of
1867 // two boundary. For example, if you pass in 3 here, you will get an 8
1868 // byte alignment. If a global value is specified, and if that global has
1869 // an explicit alignment requested, it will override the alignment request
1870 // if required for correctness.
1872 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1874 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
1876 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1879 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1880 "undefined behavior");
1881 if (getCurrentSection()->getKind().isText())
1882 OutStreamer->EmitCodeAlignment(1u << NumBits);
1884 OutStreamer->EmitValueToAlignment(1u << NumBits);
1887 //===----------------------------------------------------------------------===//
1888 // Constant emission.
1889 //===----------------------------------------------------------------------===//
1891 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1892 MCContext &Ctx = OutContext;
1894 if (CV->isNullValue() || isa<UndefValue>(CV))
1895 return MCConstantExpr::create(0, Ctx);
1897 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1898 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
1900 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1901 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
1903 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1904 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
1906 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1908 llvm_unreachable("Unknown constant value to lower!");
1911 switch (CE->getOpcode()) {
1913 // If the code isn't optimized, there may be outstanding folding
1914 // opportunities. Attempt to fold the expression using DataLayout as a
1915 // last resort before giving up.
1916 if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
1918 return lowerConstant(C);
1920 // Otherwise report the problem to the user.
1923 raw_string_ostream OS(S);
1924 OS << "Unsupported expression in static initializer: ";
1925 CE->printAsOperand(OS, /*PrintType=*/false,
1926 !MF ? nullptr : MF->getFunction()->getParent());
1927 report_fatal_error(OS.str());
1929 case Instruction::GetElementPtr: {
1930 // Generate a symbolic expression for the byte address
1931 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
1932 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
1934 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1938 int64_t Offset = OffsetAI.getSExtValue();
1939 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
1943 case Instruction::Trunc:
1944 // We emit the value and depend on the assembler to truncate the generated
1945 // expression properly. This is important for differences between
1946 // blockaddress labels. Since the two labels are in the same function, it
1947 // is reasonable to treat their delta as a 32-bit value.
1949 case Instruction::BitCast:
1950 return lowerConstant(CE->getOperand(0));
1952 case Instruction::IntToPtr: {
1953 const DataLayout &DL = getDataLayout();
1955 // Handle casts to pointers by changing them into casts to the appropriate
1956 // integer type. This promotes constant folding and simplifies this code.
1957 Constant *Op = CE->getOperand(0);
1958 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1960 return lowerConstant(Op);
1963 case Instruction::PtrToInt: {
1964 const DataLayout &DL = getDataLayout();
1966 // Support only foldable casts to/from pointers that can be eliminated by
1967 // changing the pointer to the appropriately sized integer type.
1968 Constant *Op = CE->getOperand(0);
1969 Type *Ty = CE->getType();
1971 const MCExpr *OpExpr = lowerConstant(Op);
1973 // We can emit the pointer value into this slot if the slot is an
1974 // integer slot equal to the size of the pointer.
1975 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1978 // Otherwise the pointer is smaller than the resultant integer, mask off
1979 // the high bits so we are sure to get a proper truncation if the input is
1981 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1982 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
1983 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
1986 case Instruction::Sub: {
1989 if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
1993 if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
1995 const MCExpr *RelocExpr =
1996 getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM);
1998 RelocExpr = MCBinaryExpr::createSub(
1999 MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx),
2000 MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
2001 int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
2003 RelocExpr = MCBinaryExpr::createAdd(
2004 RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
2011 // The MC library also has a right-shift operator, but it isn't consistently
2012 // signed or unsigned between different targets.
2013 case Instruction::Add:
2014 case Instruction::Mul:
2015 case Instruction::SDiv:
2016 case Instruction::SRem:
2017 case Instruction::Shl:
2018 case Instruction::And:
2019 case Instruction::Or:
2020 case Instruction::Xor: {
2021 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
2022 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
2023 switch (CE->getOpcode()) {
2024 default: llvm_unreachable("Unknown binary operator constant cast expr");
2025 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
2026 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
2027 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
2028 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
2029 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
2030 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
2031 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
2032 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
2033 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
2039 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
2041 const Constant *BaseCV = nullptr,
2042 uint64_t Offset = 0);
2044 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
2046 /// isRepeatedByteSequence - Determine whether the given value is
2047 /// composed of a repeated sequence of identical bytes and return the
2048 /// byte value. If it is not a repeated sequence, return -1.
2049 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
2050 StringRef Data = V->getRawDataValues();
2051 assert(!Data.empty() && "Empty aggregates should be CAZ node");
2053 for (unsigned i = 1, e = Data.size(); i != e; ++i)
2054 if (Data[i] != C) return -1;
2055 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
2058 /// isRepeatedByteSequence - Determine whether the given value is
2059 /// composed of a repeated sequence of identical bytes and return the
2060 /// byte value. If it is not a repeated sequence, return -1.
2061 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
2062 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
2063 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
2064 assert(Size % 8 == 0);
2066 // Extend the element to take zero padding into account.
2067 APInt Value = CI->getValue().zextOrSelf(Size);
2068 if (!Value.isSplat(8))
2071 return Value.zextOrTrunc(8).getZExtValue();
2073 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
2074 // Make sure all array elements are sequences of the same repeated
2076 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
2077 Constant *Op0 = CA->getOperand(0);
2078 int Byte = isRepeatedByteSequence(Op0, DL);
2082 // All array elements must be equal.
2083 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
2084 if (CA->getOperand(i) != Op0)
2089 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
2090 return isRepeatedByteSequence(CDS);
2095 static void emitGlobalConstantDataSequential(const DataLayout &DL,
2096 const ConstantDataSequential *CDS,
2098 // See if we can aggregate this into a .fill, if so, emit it as such.
2099 int Value = isRepeatedByteSequence(CDS, DL);
2101 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
2102 // Don't emit a 1-byte object as a .fill.
2104 return AP.OutStreamer->emitFill(Bytes, Value);
2107 // If this can be emitted with .ascii/.asciz, emit it as such.
2108 if (CDS->isString())
2109 return AP.OutStreamer->EmitBytes(CDS->getAsString());
2111 // Otherwise, emit the values in successive locations.
2112 unsigned ElementByteSize = CDS->getElementByteSize();
2113 if (isa<IntegerType>(CDS->getElementType())) {
2114 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
2116 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2117 CDS->getElementAsInteger(i));
2118 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
2122 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I)
2123 emitGlobalConstantFP(cast<ConstantFP>(CDS->getElementAsConstant(I)), AP);
2126 unsigned Size = DL.getTypeAllocSize(CDS->getType());
2127 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
2128 CDS->getNumElements();
2129 if (unsigned Padding = Size - EmittedSize)
2130 AP.OutStreamer->EmitZeros(Padding);
2133 static void emitGlobalConstantArray(const DataLayout &DL,
2134 const ConstantArray *CA, AsmPrinter &AP,
2135 const Constant *BaseCV, uint64_t Offset) {
2136 // See if we can aggregate some values. Make sure it can be
2137 // represented as a series of bytes of the constant value.
2138 int Value = isRepeatedByteSequence(CA, DL);
2141 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2142 AP.OutStreamer->emitFill(Bytes, Value);
2145 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2146 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2147 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2152 static void emitGlobalConstantVector(const DataLayout &DL,
2153 const ConstantVector *CV, AsmPrinter &AP) {
2154 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2155 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2157 unsigned Size = DL.getTypeAllocSize(CV->getType());
2158 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2159 CV->getType()->getNumElements();
2160 if (unsigned Padding = Size - EmittedSize)
2161 AP.OutStreamer->EmitZeros(Padding);
2164 static void emitGlobalConstantStruct(const DataLayout &DL,
2165 const ConstantStruct *CS, AsmPrinter &AP,
2166 const Constant *BaseCV, uint64_t Offset) {
2167 // Print the fields in successive locations. Pad to align if needed!
2168 unsigned Size = DL.getTypeAllocSize(CS->getType());
2169 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2170 uint64_t SizeSoFar = 0;
2171 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2172 const Constant *Field = CS->getOperand(i);
2174 // Print the actual field value.
2175 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2177 // Check if padding is needed and insert one or more 0s.
2178 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2179 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2180 - Layout->getElementOffset(i)) - FieldSize;
2181 SizeSoFar += FieldSize + PadSize;
2183 // Insert padding - this may include padding to increase the size of the
2184 // current field up to the ABI size (if the struct is not packed) as well
2185 // as padding to ensure that the next field starts at the right offset.
2186 AP.OutStreamer->EmitZeros(PadSize);
2188 assert(SizeSoFar == Layout->getSizeInBytes() &&
2189 "Layout of constant struct may be incorrect!");
2192 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2193 APInt API = CFP->getValueAPF().bitcastToAPInt();
2195 // First print a comment with what we think the original floating-point value
2196 // should have been.
2197 if (AP.isVerbose()) {
2198 SmallString<8> StrVal;
2199 CFP->getValueAPF().toString(StrVal);
2202 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
2204 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2205 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2208 // Now iterate through the APInt chunks, emitting them in endian-correct
2209 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2211 unsigned NumBytes = API.getBitWidth() / 8;
2212 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2213 const uint64_t *p = API.getRawData();
2215 // PPC's long double has odd notions of endianness compared to how LLVM
2216 // handles it: p[0] goes first for *big* endian on PPC.
2217 if (AP.getDataLayout().isBigEndian() && !CFP->getType()->isPPC_FP128Ty()) {
2218 int Chunk = API.getNumWords() - 1;
2221 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2223 for (; Chunk >= 0; --Chunk)
2224 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2227 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2228 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2231 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2234 // Emit the tail padding for the long double.
2235 const DataLayout &DL = AP.getDataLayout();
2236 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2237 DL.getTypeStoreSize(CFP->getType()));
2240 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2241 const DataLayout &DL = AP.getDataLayout();
2242 unsigned BitWidth = CI->getBitWidth();
2244 // Copy the value as we may massage the layout for constants whose bit width
2245 // is not a multiple of 64-bits.
2246 APInt Realigned(CI->getValue());
2247 uint64_t ExtraBits = 0;
2248 unsigned ExtraBitsSize = BitWidth & 63;
2250 if (ExtraBitsSize) {
2251 // The bit width of the data is not a multiple of 64-bits.
2252 // The extra bits are expected to be at the end of the chunk of the memory.
2254 // * Nothing to be done, just record the extra bits to emit.
2256 // * Record the extra bits to emit.
2257 // * Realign the raw data to emit the chunks of 64-bits.
2258 if (DL.isBigEndian()) {
2259 // Basically the structure of the raw data is a chunk of 64-bits cells:
2260 // 0 1 BitWidth / 64
2261 // [chunk1][chunk2] ... [chunkN].
2262 // The most significant chunk is chunkN and it should be emitted first.
2263 // However, due to the alignment issue chunkN contains useless bits.
2264 // Realign the chunks so that they contain only useless information:
2265 // ExtraBits 0 1 (BitWidth / 64) - 1
2266 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2267 ExtraBits = Realigned.getRawData()[0] &
2268 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2269 Realigned.lshrInPlace(ExtraBitsSize);
2271 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2274 // We don't expect assemblers to support integer data directives
2275 // for more than 64 bits, so we emit the data in at most 64-bit
2276 // quantities at a time.
2277 const uint64_t *RawData = Realigned.getRawData();
2278 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2279 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2280 AP.OutStreamer->EmitIntValue(Val, 8);
2283 if (ExtraBitsSize) {
2284 // Emit the extra bits after the 64-bits chunks.
2286 // Emit a directive that fills the expected size.
2287 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2288 Size -= (BitWidth / 64) * 8;
2289 assert(Size && Size * 8 >= ExtraBitsSize &&
2290 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2291 == ExtraBits && "Directive too small for extra bits.");
2292 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2296 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2297 /// equivalent global, by a target specific GOT pc relative access to the
2299 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2300 const Constant *BaseCst,
2302 // The global @foo below illustrates a global that uses a got equivalent.
2304 // @bar = global i32 42
2305 // @gotequiv = private unnamed_addr constant i32* @bar
2306 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2307 // i64 ptrtoint (i32* @foo to i64))
2310 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2311 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2314 // foo = cstexpr, where
2315 // cstexpr := <gotequiv> - "." + <cst>
2316 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2318 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2320 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2321 // gotpcrelcst := <offset from @foo base> + <cst>
2324 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2326 const MCSymbolRefExpr *SymA = MV.getSymA();
2330 // Check that GOT equivalent symbol is cached.
2331 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2332 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2335 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2339 // Check for a valid base symbol
2340 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2341 const MCSymbolRefExpr *SymB = MV.getSymB();
2343 if (!SymB || BaseSym != &SymB->getSymbol())
2346 // Make sure to match:
2348 // gotpcrelcst := <offset from @foo base> + <cst>
2350 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2351 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2352 // if the target knows how to encode it.
2354 int64_t GOTPCRelCst = Offset + MV.getConstant();
2355 if (GOTPCRelCst < 0)
2357 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2360 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2367 // .long gotequiv - "." + <cst>
2369 // is replaced by the target specific equivalent to:
2374 // .long bar@GOTPCREL+<gotpcrelcst>
2376 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2377 const GlobalVariable *GV = Result.first;
2378 int NumUses = (int)Result.second;
2379 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2380 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2381 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2382 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2384 // Update GOT equivalent usage information
2387 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2390 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2391 AsmPrinter &AP, const Constant *BaseCV,
2393 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2395 // Globals with sub-elements such as combinations of arrays and structs
2396 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2397 // constant symbol base and the current position with BaseCV and Offset.
2398 if (!BaseCV && CV->hasOneUse())
2399 BaseCV = dyn_cast<Constant>(CV->user_back());
2401 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2402 return AP.OutStreamer->EmitZeros(Size);
2404 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2411 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2412 CI->getZExtValue());
2413 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2416 emitGlobalConstantLargeInt(CI, AP);
2421 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2422 return emitGlobalConstantFP(CFP, AP);
2424 if (isa<ConstantPointerNull>(CV)) {
2425 AP.OutStreamer->EmitIntValue(0, Size);
2429 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2430 return emitGlobalConstantDataSequential(DL, CDS, AP);
2432 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2433 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2435 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2436 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2438 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2439 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2441 if (CE->getOpcode() == Instruction::BitCast)
2442 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2445 // If the constant expression's size is greater than 64-bits, then we have
2446 // to emit the value in chunks. Try to constant fold the value and emit it
2448 Constant *New = ConstantFoldConstant(CE, DL);
2449 if (New && New != CE)
2450 return emitGlobalConstantImpl(DL, New, AP);
2454 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2455 return emitGlobalConstantVector(DL, V, AP);
2457 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2458 // thread the streamer with EmitValue.
2459 const MCExpr *ME = AP.lowerConstant(CV);
2461 // Since lowerConstant already folded and got rid of all IR pointer and
2462 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2464 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2465 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2467 AP.OutStreamer->EmitValue(ME, Size);
2470 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2471 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2472 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2474 emitGlobalConstantImpl(DL, CV, *this);
2475 else if (MAI->hasSubsectionsViaSymbols()) {
2476 // If the global has zero size, emit a single byte so that two labels don't
2477 // look like they are at the same location.
2478 OutStreamer->EmitIntValue(0, 1);
2482 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2483 // Target doesn't support this yet!
2484 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2487 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2489 OS << '+' << Offset;
2490 else if (Offset < 0)
2494 //===----------------------------------------------------------------------===//
2495 // Symbol Lowering Routines.
2496 //===----------------------------------------------------------------------===//
2498 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2499 return OutContext.createTempSymbol(Name, true);
2502 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2503 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2506 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2507 return MMI->getAddrLabelSymbol(BB);
2510 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2511 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2512 const DataLayout &DL = getDataLayout();
2513 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2514 "CPI" + Twine(getFunctionNumber()) + "_" +
2518 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2519 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2520 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2523 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2524 /// FIXME: privatize to AsmPrinter.
2525 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2526 const DataLayout &DL = getDataLayout();
2527 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2528 Twine(getFunctionNumber()) + "_" +
2529 Twine(UID) + "_set_" + Twine(MBBID));
2532 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2533 StringRef Suffix) const {
2534 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM);
2537 /// Return the MCSymbol for the specified ExternalSymbol.
2538 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2539 SmallString<60> NameStr;
2540 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2541 return OutContext.getOrCreateSymbol(NameStr);
2544 /// PrintParentLoopComment - Print comments about parent loops of this one.
2545 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2546 unsigned FunctionNumber) {
2548 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2549 OS.indent(Loop->getLoopDepth()*2)
2550 << "Parent Loop BB" << FunctionNumber << "_"
2551 << Loop->getHeader()->getNumber()
2552 << " Depth=" << Loop->getLoopDepth() << '\n';
2556 /// PrintChildLoopComment - Print comments about child loops within
2557 /// the loop for this basic block, with nesting.
2558 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2559 unsigned FunctionNumber) {
2560 // Add child loop information
2561 for (const MachineLoop *CL : *Loop) {
2562 OS.indent(CL->getLoopDepth()*2)
2563 << "Child Loop BB" << FunctionNumber << "_"
2564 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2566 PrintChildLoopComment(OS, CL, FunctionNumber);
2570 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2571 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2572 const MachineLoopInfo *LI,
2573 const AsmPrinter &AP) {
2574 // Add loop depth information
2575 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2578 MachineBasicBlock *Header = Loop->getHeader();
2579 assert(Header && "No header for loop");
2581 // If this block is not a loop header, just print out what is the loop header
2583 if (Header != &MBB) {
2584 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2585 Twine(AP.getFunctionNumber())+"_" +
2586 Twine(Loop->getHeader()->getNumber())+
2587 " Depth="+Twine(Loop->getLoopDepth()));
2591 // Otherwise, it is a loop header. Print out information about child and
2593 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2595 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2598 OS.indent(Loop->getLoopDepth()*2-2);
2603 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2605 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2608 /// EmitBasicBlockStart - This method prints the label for the specified
2609 /// MachineBasicBlock, an alignment (if present) and a comment describing
2610 /// it if appropriate.
2611 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2612 // End the previous funclet and start a new one.
2613 if (MBB.isEHFuncletEntry()) {
2614 for (const HandlerInfo &HI : Handlers) {
2615 HI.Handler->endFunclet();
2616 HI.Handler->beginFunclet(MBB);
2620 // Emit an alignment directive for this block, if needed.
2621 if (unsigned Align = MBB.getAlignment())
2622 EmitAlignment(Align);
2624 // If the block has its address taken, emit any labels that were used to
2625 // reference the block. It is possible that there is more than one label
2626 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2627 // the references were generated.
2628 if (MBB.hasAddressTaken()) {
2629 const BasicBlock *BB = MBB.getBasicBlock();
2631 OutStreamer->AddComment("Block address taken");
2633 // MBBs can have their address taken as part of CodeGen without having
2634 // their corresponding BB's address taken in IR
2635 if (BB->hasAddressTaken())
2636 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2637 OutStreamer->EmitLabel(Sym);
2640 // Print some verbose block comments.
2642 if (const BasicBlock *BB = MBB.getBasicBlock()) {
2643 if (BB->hasName()) {
2644 BB->printAsOperand(OutStreamer->GetCommentOS(),
2645 /*PrintType=*/false, BB->getModule());
2646 OutStreamer->GetCommentOS() << '\n';
2649 emitBasicBlockLoopComments(MBB, LI, *this);
2652 // Print the main label for the block.
2653 if (MBB.pred_empty() ||
2654 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2656 // NOTE: Want this comment at start of line, don't emit with AddComment.
2657 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2660 OutStreamer->EmitLabel(MBB.getSymbol());
2664 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2665 bool IsDefinition) const {
2666 MCSymbolAttr Attr = MCSA_Invalid;
2668 switch (Visibility) {
2670 case GlobalValue::HiddenVisibility:
2672 Attr = MAI->getHiddenVisibilityAttr();
2674 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2676 case GlobalValue::ProtectedVisibility:
2677 Attr = MAI->getProtectedVisibilityAttr();
2681 if (Attr != MCSA_Invalid)
2682 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2685 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2686 /// exactly one predecessor and the control transfer mechanism between
2687 /// the predecessor and this block is a fall-through.
2689 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2690 // If this is a landing pad, it isn't a fall through. If it has no preds,
2691 // then nothing falls through to it.
2692 if (MBB->isEHPad() || MBB->pred_empty())
2695 // If there isn't exactly one predecessor, it can't be a fall through.
2696 if (MBB->pred_size() > 1)
2699 // The predecessor has to be immediately before this block.
2700 MachineBasicBlock *Pred = *MBB->pred_begin();
2701 if (!Pred->isLayoutSuccessor(MBB))
2704 // If the block is completely empty, then it definitely does fall through.
2708 // Check the terminators in the previous blocks
2709 for (const auto &MI : Pred->terminators()) {
2710 // If it is not a simple branch, we are in a table somewhere.
2711 if (!MI.isBranch() || MI.isIndirectBranch())
2714 // If we are the operands of one of the branches, this is not a fall
2715 // through. Note that targets with delay slots will usually bundle
2716 // terminators with the delay slot instruction.
2717 for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
2720 if (OP->isMBB() && OP->getMBB() == MBB)
2728 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2729 if (!S.usesMetadata())
2732 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2733 " stackmap formats, please see the documentation for a description of"
2734 " the default format. If you really need a custom serialized format,"
2735 " please file a bug");
2737 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2738 gcp_map_type::iterator GCPI = GCMap.find(&S);
2739 if (GCPI != GCMap.end())
2740 return GCPI->second.get();
2742 auto Name = S.getName();
2744 for (GCMetadataPrinterRegistry::iterator
2745 I = GCMetadataPrinterRegistry::begin(),
2746 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2747 if (Name == I->getName()) {
2748 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2750 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2751 return IterBool.first->second.get();
2754 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2757 /// Pin vtable to this file.
2758 AsmPrinterHandler::~AsmPrinterHandler() = default;
2760 void AsmPrinterHandler::markFunctionEnd() {}
2762 // In the binary's "xray_instr_map" section, an array of these function entries
2763 // describes each instrumentation point. When XRay patches your code, the index
2764 // into this table will be given to your handler as a patch point identifier.
2765 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out,
2766 const MCSymbol *CurrentFnSym) const {
2767 Out->EmitSymbolValue(Sled, Bytes);
2768 Out->EmitSymbolValue(CurrentFnSym, Bytes);
2769 auto Kind8 = static_cast<uint8_t>(Kind);
2770 Out->EmitBytes(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
2772 StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
2773 Out->EmitZeros(2 * Bytes - 2); // Pad the previous two entries
2776 void AsmPrinter::emitXRayTable() {
2780 auto PrevSection = OutStreamer->getCurrentSectionOnly();
2781 auto Fn = MF->getFunction();
2782 MCSection *InstMap = nullptr;
2783 MCSection *FnSledIndex = nullptr;
2784 if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) {
2785 if (Fn->hasComdat()) {
2786 InstMap = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
2787 ELF::SHF_ALLOC | ELF::SHF_GROUP, 0,
2788 Fn->getComdat()->getName());
2789 FnSledIndex = OutContext.getELFSection("xray_fn_idx", ELF::SHT_PROGBITS,
2790 ELF::SHF_ALLOC | ELF::SHF_GROUP, 0,
2791 Fn->getComdat()->getName());
2793 InstMap = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
2795 FnSledIndex = OutContext.getELFSection("xray_fn_idx", ELF::SHT_PROGBITS,
2798 } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
2799 InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map", 0,
2800 SectionKind::getReadOnlyWithRel());
2801 FnSledIndex = OutContext.getMachOSection("__DATA", "xray_fn_idx", 0,
2802 SectionKind::getReadOnlyWithRel());
2804 llvm_unreachable("Unsupported target");
2807 // Before we switch over, we force a reference to a label inside the
2808 // xray_instr_map and xray_fn_idx sections. Since this function is always
2809 // called just before the function's end, we assume that this is happening
2810 // after the last return instruction. We also use the synthetic label in the
2811 // xray_inster_map as a delimeter for the range of sleds for this function in
2813 auto WordSizeBytes = MAI->getCodePointerSize();
2814 MCSymbol *SledsStart = OutContext.createTempSymbol("xray_synthetic_", true);
2815 MCSymbol *IdxRef = OutContext.createTempSymbol("xray_fn_idx_synth_", true);
2816 OutStreamer->EmitCodeAlignment(16);
2817 OutStreamer->EmitSymbolValue(SledsStart, WordSizeBytes, false);
2818 OutStreamer->EmitSymbolValue(IdxRef, WordSizeBytes, false);
2820 // Now we switch to the instrumentation map section. Because this is done
2821 // per-function, we are able to create an index entry that will represent the
2822 // range of sleds associated with a function.
2823 OutStreamer->SwitchSection(InstMap);
2824 OutStreamer->EmitLabel(SledsStart);
2825 for (const auto &Sled : Sleds)
2826 Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym);
2827 MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_synthetic_end", true);
2828 OutStreamer->EmitLabel(SledsEnd);
2830 // We then emit a single entry in the index per function. We use the symbols
2831 // that bound the instrumentation map as the range for a specific function.
2832 // Each entry here will be 2 * word size aligned, as we're writing down two
2833 // pointers. This should work for both 32-bit and 64-bit platforms.
2834 OutStreamer->SwitchSection(FnSledIndex);
2835 OutStreamer->EmitCodeAlignment(2 * WordSizeBytes);
2836 OutStreamer->EmitLabel(IdxRef);
2837 OutStreamer->EmitSymbolValue(SledsStart, WordSizeBytes);
2838 OutStreamer->EmitSymbolValue(SledsEnd, WordSizeBytes);
2839 OutStreamer->SwitchSection(PrevSection);
2843 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
2845 auto Fn = MI.getParent()->getParent()->getFunction();
2846 auto Attr = Fn->getFnAttribute("function-instrument");
2847 bool LogArgs = Fn->hasFnAttribute("xray-log-args");
2848 bool AlwaysInstrument =
2849 Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always";
2850 if (Kind == SledKind::FUNCTION_ENTER && LogArgs)
2851 Kind = SledKind::LOG_ARGS_ENTER;
2853 XRayFunctionEntry{ Sled, CurrentFnSym, Kind, AlwaysInstrument, Fn });
2856 uint16_t AsmPrinter::getDwarfVersion() const {
2857 return OutStreamer->getContext().getDwarfVersion();
2860 void AsmPrinter::setDwarfVersion(uint16_t Version) {
2861 OutStreamer->getContext().setDwarfVersion(Version);