1 //===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the AsmPrinter class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/AsmPrinter.h"
15 #include "DwarfDebug.h"
16 #include "DwarfException.h"
17 #include "WinException.h"
18 #include "WinCodeViewLineTables.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/Analysis/ConstantFolding.h"
22 #include "llvm/CodeGen/Analysis.h"
23 #include "llvm/CodeGen/GCMetadataPrinter.h"
24 #include "llvm/CodeGen/MachineConstantPool.h"
25 #include "llvm/CodeGen/MachineFrameInfo.h"
26 #include "llvm/CodeGen/MachineFunction.h"
27 #include "llvm/CodeGen/MachineInstrBundle.h"
28 #include "llvm/CodeGen/MachineJumpTableInfo.h"
29 #include "llvm/CodeGen/MachineLoopInfo.h"
30 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
31 #include "llvm/IR/DataLayout.h"
32 #include "llvm/IR/DebugInfo.h"
33 #include "llvm/IR/Mangler.h"
34 #include "llvm/IR/Module.h"
35 #include "llvm/IR/Operator.h"
36 #include "llvm/MC/MCAsmInfo.h"
37 #include "llvm/MC/MCContext.h"
38 #include "llvm/MC/MCExpr.h"
39 #include "llvm/MC/MCInst.h"
40 #include "llvm/MC/MCSection.h"
41 #include "llvm/MC/MCStreamer.h"
42 #include "llvm/MC/MCSymbolELF.h"
43 #include "llvm/MC/MCValue.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/Format.h"
46 #include "llvm/Support/MathExtras.h"
47 #include "llvm/Support/TargetRegistry.h"
48 #include "llvm/Support/Timer.h"
49 #include "llvm/Target/TargetFrameLowering.h"
50 #include "llvm/Target/TargetInstrInfo.h"
51 #include "llvm/Target/TargetLowering.h"
52 #include "llvm/Target/TargetLoweringObjectFile.h"
53 #include "llvm/Target/TargetRegisterInfo.h"
54 #include "llvm/Target/TargetSubtargetInfo.h"
57 #define DEBUG_TYPE "asm-printer"
59 static const char *const DWARFGroupName = "DWARF Emission";
60 static const char *const DbgTimerName = "Debug Info Emission";
61 static const char *const EHTimerName = "DWARF Exception Writer";
62 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
64 STATISTIC(EmittedInsts, "Number of machine instrs printed");
66 char AsmPrinter::ID = 0;
68 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
69 static gcp_map_type &getGCMap(void *&P) {
71 P = new gcp_map_type();
72 return *(gcp_map_type*)P;
76 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
77 /// value in log2 form. This rounds up to the preferred alignment if possible
79 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
80 unsigned InBits = 0) {
82 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
83 NumBits = DL.getPreferredAlignmentLog(GVar);
85 // If InBits is specified, round it to it.
89 // If the GV has a specified alignment, take it into account.
90 if (GV->getAlignment() == 0)
93 unsigned GVAlign = Log2_32(GV->getAlignment());
95 // If the GVAlign is larger than NumBits, or if we are required to obey
96 // NumBits because the GV has an assigned section, obey it.
97 if (GVAlign > NumBits || GV->hasSection())
102 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
103 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
104 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)),
105 LastMI(nullptr), LastFn(0), Counter(~0U) {
110 CurExceptionSym = CurrentFnSym = CurrentFnSymForSize = nullptr;
111 CurrentFnBegin = nullptr;
112 CurrentFnEnd = nullptr;
113 GCMetadataPrinters = nullptr;
114 VerboseAsm = OutStreamer->isVerboseAsm();
117 AsmPrinter::~AsmPrinter() {
118 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
120 if (GCMetadataPrinters) {
121 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
124 GCMetadataPrinters = nullptr;
128 /// getFunctionNumber - Return a unique ID for the current function.
130 unsigned AsmPrinter::getFunctionNumber() const {
131 return MF->getFunctionNumber();
134 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
135 return *TM.getObjFileLowering();
138 const DataLayout &AsmPrinter::getDataLayout() const {
139 return MMI->getModule()->getDataLayout();
142 // Do not use the cached DataLayout because some client use it without a Module
143 // (llmv-dsymutil, llvm-dwarfdump).
144 unsigned AsmPrinter::getPointerSize() const { return TM.getPointerSize(); }
146 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
147 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
148 return MF->getSubtarget<MCSubtargetInfo>();
151 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
152 S.EmitInstruction(Inst, getSubtargetInfo());
155 StringRef AsmPrinter::getTargetTriple() const {
156 return TM.getTargetTriple().str();
159 /// getCurrentSection() - Return the current section we are emitting to.
160 const MCSection *AsmPrinter::getCurrentSection() const {
161 return OutStreamer->getCurrentSection().first;
166 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
167 AU.setPreservesAll();
168 MachineFunctionPass::getAnalysisUsage(AU);
169 AU.addRequired<MachineModuleInfo>();
170 AU.addRequired<GCModuleInfo>();
172 AU.addRequired<MachineLoopInfo>();
175 bool AsmPrinter::doInitialization(Module &M) {
176 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
178 // Initialize TargetLoweringObjectFile.
179 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
180 .Initialize(OutContext, TM);
182 OutStreamer->InitSections(false);
184 Mang = new Mangler();
186 // Emit the version-min deplyment target directive if needed.
188 // FIXME: If we end up with a collection of these sorts of Darwin-specific
189 // or ELF-specific things, it may make sense to have a platform helper class
190 // that will work with the target helper class. For now keep it here, as the
191 // alternative is duplicated code in each of the target asm printers that
192 // use the directive, where it would need the same conditionalization
194 Triple TT(getTargetTriple());
195 // If there is a version specified, Major will be non-zero.
196 if (TT.isOSDarwin() && TT.getOSMajorVersion() != 0) {
197 unsigned Major, Minor, Update;
198 MCVersionMinType VersionType;
199 if (TT.isWatchOS()) {
200 VersionType = MCVM_WatchOSVersionMin;
201 TT.getWatchOSVersion(Major, Minor, Update);
202 } else if (TT.isTvOS()) {
203 VersionType = MCVM_TvOSVersionMin;
204 TT.getiOSVersion(Major, Minor, Update);
205 } else if (TT.isMacOSX()) {
206 VersionType = MCVM_OSXVersionMin;
207 if (!TT.getMacOSXVersion(Major, Minor, Update))
210 VersionType = MCVM_IOSVersionMin;
211 TT.getiOSVersion(Major, Minor, Update);
214 OutStreamer->EmitVersionMin(VersionType, Major, Minor, Update);
217 // Allow the target to emit any magic that it wants at the start of the file.
218 EmitStartOfAsmFile(M);
220 // Very minimal debug info. It is ignored if we emit actual debug info. If we
221 // don't, this at least helps the user find where a global came from.
222 if (MAI->hasSingleParameterDotFile()) {
224 OutStreamer->EmitFileDirective(M.getModuleIdentifier());
227 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
228 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
230 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
231 MP->beginAssembly(M, *MI, *this);
233 // Emit module-level inline asm if it exists.
234 if (!M.getModuleInlineAsm().empty()) {
235 // We're at the module level. Construct MCSubtarget from the default CPU
236 // and target triple.
237 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
238 TM.getTargetTriple().str(), TM.getTargetCPU(),
239 TM.getTargetFeatureString()));
240 OutStreamer->AddComment("Start of file scope inline assembly");
241 OutStreamer->AddBlankLine();
242 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
243 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
244 OutStreamer->AddComment("End of file scope inline assembly");
245 OutStreamer->AddBlankLine();
248 if (MAI->doesSupportDebugInformation()) {
249 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
250 if (EmitCodeView && TM.getTargetTriple().isKnownWindowsMSVCEnvironment()) {
251 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
253 CodeViewLineTablesGroupName));
255 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
256 DD = new DwarfDebug(this, &M);
257 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
261 EHStreamer *ES = nullptr;
262 switch (MAI->getExceptionHandlingType()) {
263 case ExceptionHandling::None:
265 case ExceptionHandling::SjLj:
266 case ExceptionHandling::DwarfCFI:
267 ES = new DwarfCFIException(this);
269 case ExceptionHandling::ARM:
270 ES = new ARMException(this);
272 case ExceptionHandling::WinEH:
273 switch (MAI->getWinEHEncodingType()) {
274 default: llvm_unreachable("unsupported unwinding information encoding");
275 case WinEH::EncodingType::Invalid:
277 case WinEH::EncodingType::X86:
278 case WinEH::EncodingType::Itanium:
279 ES = new WinException(this);
285 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
289 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
290 if (!MAI.hasWeakDefCanBeHiddenDirective())
293 return canBeOmittedFromSymbolTable(GV);
296 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
297 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
299 case GlobalValue::CommonLinkage:
300 case GlobalValue::LinkOnceAnyLinkage:
301 case GlobalValue::LinkOnceODRLinkage:
302 case GlobalValue::WeakAnyLinkage:
303 case GlobalValue::WeakODRLinkage:
304 if (MAI->hasWeakDefDirective()) {
306 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
308 if (!canBeHidden(GV, *MAI))
309 // .weak_definition _foo
310 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
312 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
313 } else if (MAI->hasLinkOnceDirective()) {
315 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
316 //NOTE: linkonce is handled by the section the symbol was assigned to.
319 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
322 case GlobalValue::AppendingLinkage:
323 // FIXME: appending linkage variables should go into a section of
324 // their name or something. For now, just emit them as external.
325 case GlobalValue::ExternalLinkage:
326 // If external or appending, declare as a global symbol.
328 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
330 case GlobalValue::PrivateLinkage:
331 case GlobalValue::InternalLinkage:
333 case GlobalValue::AvailableExternallyLinkage:
334 llvm_unreachable("Should never emit this");
335 case GlobalValue::ExternalWeakLinkage:
336 llvm_unreachable("Don't know how to emit these");
338 llvm_unreachable("Unknown linkage type!");
341 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
342 const GlobalValue *GV) const {
343 TM.getNameWithPrefix(Name, GV, *Mang);
346 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
347 return TM.getSymbol(GV, *Mang);
350 static MCSymbol *getOrCreateEmuTLSControlSym(MCSymbol *GVSym, MCContext &C) {
351 return C.getOrCreateSymbol(Twine("__emutls_v.") + GVSym->getName());
354 static MCSymbol *getOrCreateEmuTLSInitSym(MCSymbol *GVSym, MCContext &C) {
355 return C.getOrCreateSymbol(Twine("__emutls_t.") + GVSym->getName());
358 /// EmitEmulatedTLSControlVariable - Emit the control variable for an emulated TLS variable.
359 void AsmPrinter::EmitEmulatedTLSControlVariable(const GlobalVariable *GV,
360 MCSymbol *EmittedSym,
361 bool AllZeroInitValue) {
362 MCSection *TLSVarSection = getObjFileLowering().getDataSection();
363 OutStreamer->SwitchSection(TLSVarSection);
364 MCSymbol *GVSym = getSymbol(GV);
365 EmitLinkage(GV, EmittedSym); // same linkage as GV
366 const DataLayout &DL = GV->getParent()->getDataLayout();
367 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
368 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
369 unsigned WordSize = DL.getPointerSize();
370 unsigned Alignment = DL.getPointerABIAlignment();
371 EmitAlignment(Log2_32(Alignment));
372 OutStreamer->EmitLabel(EmittedSym);
373 OutStreamer->EmitIntValue(Size, WordSize);
374 OutStreamer->EmitIntValue((1 << AlignLog), WordSize);
375 OutStreamer->EmitIntValue(0, WordSize);
376 if (GV->hasInitializer() && !AllZeroInitValue) {
377 OutStreamer->EmitSymbolValue(
378 getOrCreateEmuTLSInitSym(GVSym, OutContext), WordSize);
380 OutStreamer->EmitIntValue(0, WordSize);
381 if (MAI->hasDotTypeDotSizeDirective())
382 OutStreamer->emitELFSize(cast<MCSymbolELF>(EmittedSym),
383 MCConstantExpr::create(4 * WordSize, OutContext));
384 OutStreamer->AddBlankLine(); // End of the __emutls_v.* variable.
387 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
388 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
390 GV->getThreadLocalMode() != llvm::GlobalVariable::NotThreadLocal &&
391 TM.Options.EmulatedTLS;
392 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
393 "No emulated TLS variables in the common section");
395 if (GV->hasInitializer()) {
396 // Check to see if this is a special global used by LLVM, if so, emit it.
397 if (EmitSpecialLLVMGlobal(GV))
400 // Skip the emission of global equivalents. The symbol can be emitted later
401 // on by emitGlobalGOTEquivs in case it turns out to be needed.
402 if (GlobalGOTEquivs.count(getSymbol(GV)))
405 if (isVerbose() && !IsEmuTLSVar) {
406 // When printing the control variable __emutls_v.*,
407 // we don't need to print the original TLS variable name.
408 GV->printAsOperand(OutStreamer->GetCommentOS(),
409 /*PrintType=*/false, GV->getParent());
410 OutStreamer->GetCommentOS() << '\n';
414 MCSymbol *GVSym = getSymbol(GV);
415 MCSymbol *EmittedSym = IsEmuTLSVar ?
416 getOrCreateEmuTLSControlSym(GVSym, OutContext) : GVSym;
417 // getOrCreateEmuTLSControlSym only creates the symbol with name and default attributes.
418 // GV's or GVSym's attributes will be used for the EmittedSym.
420 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
422 if (!GV->hasInitializer()) // External globals require no extra code.
425 GVSym->redefineIfPossible();
426 if (GVSym->isDefined() || GVSym->isVariable())
427 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
428 "' is already defined");
430 if (MAI->hasDotTypeDotSizeDirective())
431 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
433 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
435 const DataLayout &DL = GV->getParent()->getDataLayout();
436 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
438 // If the alignment is specified, we *must* obey it. Overaligning a global
439 // with a specified alignment is a prompt way to break globals emitted to
440 // sections and expected to be contiguous (e.g. ObjC metadata).
441 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
443 bool AllZeroInitValue = false;
444 const Constant *InitValue = GV->getInitializer();
445 if (isa<ConstantAggregateZero>(InitValue))
446 AllZeroInitValue = true;
448 const ConstantInt *InitIntValue = dyn_cast<ConstantInt>(InitValue);
449 if (InitIntValue && InitIntValue->isZero())
450 AllZeroInitValue = true;
453 EmitEmulatedTLSControlVariable(GV, EmittedSym, AllZeroInitValue);
455 for (const HandlerInfo &HI : Handlers) {
456 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
457 HI.Handler->setSymbolSize(GVSym, Size);
460 // Handle common and BSS local symbols (.lcomm).
461 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
462 assert(!(IsEmuTLSVar && GVKind.isCommon()) &&
463 "No emulated TLS variables in the common section");
464 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
465 unsigned Align = 1 << AlignLog;
467 // Handle common symbols.
468 if (GVKind.isCommon()) {
469 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
473 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
477 // Handle local BSS symbols.
478 if (MAI->hasMachoZeroFillDirective()) {
479 MCSection *TheSection =
480 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
481 // .zerofill __DATA, __bss, _foo, 400, 5
482 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
486 // Use .lcomm only if it supports user-specified alignment.
487 // Otherwise, while it would still be correct to use .lcomm in some
488 // cases (e.g. when Align == 1), the external assembler might enfore
489 // some -unknown- default alignment behavior, which could cause
490 // spurious differences between external and integrated assembler.
491 // Prefer to simply fall back to .local / .comm in this case.
492 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
494 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
498 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
502 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
504 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
508 if (IsEmuTLSVar && AllZeroInitValue)
509 return; // No need of initialization values.
511 MCSymbol *EmittedInitSym = IsEmuTLSVar ?
512 getOrCreateEmuTLSInitSym(GVSym, OutContext) : GVSym;
513 // getOrCreateEmuTLSInitSym only creates the symbol with name and default attributes.
514 // GV's or GVSym's attributes will be used for the EmittedInitSym.
516 MCSection *TheSection = IsEmuTLSVar ?
517 getObjFileLowering().getReadOnlySection() :
518 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
520 // Handle the zerofill directive on darwin, which is a special form of BSS
522 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective() && !IsEmuTLSVar) {
523 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
526 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
527 // .zerofill __DATA, __common, _foo, 400, 5
528 OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
532 // Handle thread local data for mach-o which requires us to output an
533 // additional structure of data and mangle the original symbol so that we
534 // can reference it later.
536 // TODO: This should become an "emit thread local global" method on TLOF.
537 // All of this macho specific stuff should be sunk down into TLOFMachO and
538 // stuff like "TLSExtraDataSection" should no longer be part of the parent
539 // TLOF class. This will also make it more obvious that stuff like
540 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
542 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective() && !IsEmuTLSVar) {
543 // Emit the .tbss symbol
545 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
547 if (GVKind.isThreadBSS()) {
548 TheSection = getObjFileLowering().getTLSBSSSection();
549 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
550 } else if (GVKind.isThreadData()) {
551 OutStreamer->SwitchSection(TheSection);
553 EmitAlignment(AlignLog, GV);
554 OutStreamer->EmitLabel(MangSym);
556 EmitGlobalConstant(GV->getParent()->getDataLayout(),
557 GV->getInitializer());
560 OutStreamer->AddBlankLine();
562 // Emit the variable struct for the runtime.
563 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
565 OutStreamer->SwitchSection(TLVSect);
566 // Emit the linkage here.
567 EmitLinkage(GV, GVSym);
568 OutStreamer->EmitLabel(GVSym);
570 // Three pointers in size:
571 // - __tlv_bootstrap - used to make sure support exists
572 // - spare pointer, used when mapped by the runtime
573 // - pointer to mangled symbol above with initializer
574 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
575 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
577 OutStreamer->EmitIntValue(0, PtrSize);
578 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
580 OutStreamer->AddBlankLine();
584 OutStreamer->SwitchSection(TheSection);
586 // emutls_t.* symbols are only used in the current compilation unit.
588 EmitLinkage(GV, EmittedInitSym);
589 EmitAlignment(AlignLog, GV);
591 OutStreamer->EmitLabel(EmittedInitSym);
593 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
595 if (MAI->hasDotTypeDotSizeDirective())
597 OutStreamer->emitELFSize(cast<MCSymbolELF>(EmittedInitSym),
598 MCConstantExpr::create(Size, OutContext));
600 OutStreamer->AddBlankLine();
603 /// EmitFunctionHeader - This method emits the header for the current
605 void AsmPrinter::EmitFunctionHeader() {
606 // Print out constants referenced by the function
609 // Print the 'header' of function.
610 const Function *F = MF->getFunction();
612 OutStreamer->SwitchSection(
613 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
614 EmitVisibility(CurrentFnSym, F->getVisibility());
616 EmitLinkage(F, CurrentFnSym);
617 if (MAI->hasFunctionAlignment())
618 EmitAlignment(MF->getAlignment(), F);
620 if (MAI->hasDotTypeDotSizeDirective())
621 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
624 F->printAsOperand(OutStreamer->GetCommentOS(),
625 /*PrintType=*/false, F->getParent());
626 OutStreamer->GetCommentOS() << '\n';
629 // Emit the prefix data.
630 if (F->hasPrefixData())
631 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
633 // Emit the CurrentFnSym. This is a virtual function to allow targets to
634 // do their wild and crazy things as required.
635 EmitFunctionEntryLabel();
637 // If the function had address-taken blocks that got deleted, then we have
638 // references to the dangling symbols. Emit them at the start of the function
639 // so that we don't get references to undefined symbols.
640 std::vector<MCSymbol*> DeadBlockSyms;
641 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
642 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
643 OutStreamer->AddComment("Address taken block that was later removed");
644 OutStreamer->EmitLabel(DeadBlockSyms[i]);
647 if (CurrentFnBegin) {
648 if (MAI->useAssignmentForEHBegin()) {
649 MCSymbol *CurPos = OutContext.createTempSymbol();
650 OutStreamer->EmitLabel(CurPos);
651 OutStreamer->EmitAssignment(CurrentFnBegin,
652 MCSymbolRefExpr::create(CurPos, OutContext));
654 OutStreamer->EmitLabel(CurrentFnBegin);
658 // Emit pre-function debug and/or EH information.
659 for (const HandlerInfo &HI : Handlers) {
660 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
661 HI.Handler->beginFunction(MF);
664 // Emit the prologue data.
665 if (F->hasPrologueData())
666 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrologueData());
669 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
670 /// function. This can be overridden by targets as required to do custom stuff.
671 void AsmPrinter::EmitFunctionEntryLabel() {
672 CurrentFnSym->redefineIfPossible();
674 // The function label could have already been emitted if two symbols end up
675 // conflicting due to asm renaming. Detect this and emit an error.
676 if (CurrentFnSym->isVariable())
677 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
678 "' is a protected alias");
679 if (CurrentFnSym->isDefined())
680 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
681 "' label emitted multiple times to assembly file");
683 return OutStreamer->EmitLabel(CurrentFnSym);
686 /// emitComments - Pretty-print comments for instructions.
687 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
688 const MachineFunction *MF = MI.getParent()->getParent();
689 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
691 // Check for spills and reloads
694 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
696 // We assume a single instruction only has a spill or reload, not
698 const MachineMemOperand *MMO;
699 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
700 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
701 MMO = *MI.memoperands_begin();
702 CommentOS << MMO->getSize() << "-byte Reload\n";
704 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
705 if (FrameInfo->isSpillSlotObjectIndex(FI))
706 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
707 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
708 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
709 MMO = *MI.memoperands_begin();
710 CommentOS << MMO->getSize() << "-byte Spill\n";
712 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
713 if (FrameInfo->isSpillSlotObjectIndex(FI))
714 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
717 // Check for spill-induced copies
718 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
719 CommentOS << " Reload Reuse\n";
722 /// emitImplicitDef - This method emits the specified machine instruction
723 /// that is an implicit def.
724 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
725 unsigned RegNo = MI->getOperand(0).getReg();
727 SmallString<128> Str;
728 raw_svector_ostream OS(Str);
729 OS << "implicit-def: "
730 << PrintReg(RegNo, MF->getSubtarget().getRegisterInfo());
732 OutStreamer->AddComment(OS.str());
733 OutStreamer->AddBlankLine();
736 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
738 raw_string_ostream OS(Str);
740 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
741 const MachineOperand &Op = MI->getOperand(i);
742 assert(Op.isReg() && "KILL instruction must have only register operands");
744 << PrintReg(Op.getReg(),
745 AP.MF->getSubtarget().getRegisterInfo())
746 << (Op.isDef() ? "<def>" : "<kill>");
748 AP.OutStreamer->AddComment(Str);
749 AP.OutStreamer->AddBlankLine();
752 /// emitDebugValueComment - This method handles the target-independent form
753 /// of DBG_VALUE, returning true if it was able to do so. A false return
754 /// means the target will need to handle MI in EmitInstruction.
755 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
756 // This code handles only the 4-operand target-independent form.
757 if (MI->getNumOperands() != 4)
760 SmallString<128> Str;
761 raw_svector_ostream OS(Str);
762 OS << "DEBUG_VALUE: ";
764 const DILocalVariable *V = MI->getDebugVariable();
765 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
766 StringRef Name = SP->getDisplayName();
772 const DIExpression *Expr = MI->getDebugExpression();
773 if (Expr->isBitPiece())
774 OS << " [bit_piece offset=" << Expr->getBitPieceOffset()
775 << " size=" << Expr->getBitPieceSize() << "]";
778 // The second operand is only an offset if it's an immediate.
779 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
780 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
782 for (unsigned i = 0; i < Expr->getNumElements(); ++i) {
784 // We currently don't support extra Offsets or derefs after the first
785 // one. Bail out early instead of emitting an incorrect comment
786 OS << " [complex expression]";
787 AP.OutStreamer->emitRawComment(OS.str());
790 uint64_t Op = Expr->getElement(i);
791 if (Op == dwarf::DW_OP_deref) {
794 } else if (Op == dwarf::DW_OP_bit_piece) {
795 // There can't be any operands after this in a valid expression
798 uint64_t ExtraOffset = Expr->getElement(i++);
799 if (Op == dwarf::DW_OP_plus)
800 Offset += ExtraOffset;
802 assert(Op == dwarf::DW_OP_minus);
803 Offset -= ExtraOffset;
807 // Register or immediate value. Register 0 means undef.
808 if (MI->getOperand(0).isFPImm()) {
809 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
810 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
811 OS << (double)APF.convertToFloat();
812 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
813 OS << APF.convertToDouble();
815 // There is no good way to print long double. Convert a copy to
816 // double. Ah well, it's only a comment.
818 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
820 OS << "(long double) " << APF.convertToDouble();
822 } else if (MI->getOperand(0).isImm()) {
823 OS << MI->getOperand(0).getImm();
824 } else if (MI->getOperand(0).isCImm()) {
825 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
828 if (MI->getOperand(0).isReg()) {
829 Reg = MI->getOperand(0).getReg();
831 assert(MI->getOperand(0).isFI() && "Unknown operand type");
832 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
833 Offset += TFI->getFrameIndexReference(*AP.MF,
834 MI->getOperand(0).getIndex(), Reg);
838 // Suppress offset, it is not meaningful here.
840 // NOTE: Want this comment at start of line, don't emit with AddComment.
841 AP.OutStreamer->emitRawComment(OS.str());
846 OS << PrintReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
850 OS << '+' << Offset << ']';
852 // NOTE: Want this comment at start of line, don't emit with AddComment.
853 AP.OutStreamer->emitRawComment(OS.str());
857 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
858 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
859 MF->getFunction()->needsUnwindTableEntry())
862 if (MMI->hasDebugInfo())
868 bool AsmPrinter::needsSEHMoves() {
869 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
872 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
873 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
874 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
875 ExceptionHandlingType != ExceptionHandling::ARM)
878 if (needsCFIMoves() == CFI_M_None)
881 const MachineModuleInfo &MMI = MF->getMMI();
882 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
883 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
884 const MCCFIInstruction &CFI = Instrs[CFIIndex];
885 emitCFIInstruction(CFI);
888 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
889 // The operands are the MCSymbol and the frame offset of the allocation.
890 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
891 int FrameOffset = MI.getOperand(1).getImm();
893 // Emit a symbol assignment.
894 OutStreamer->EmitAssignment(FrameAllocSym,
895 MCConstantExpr::create(FrameOffset, OutContext));
898 /// EmitFunctionBody - This method emits the body and trailer for a
900 void AsmPrinter::EmitFunctionBody() {
901 EmitFunctionHeader();
903 // Emit target-specific gunk before the function body.
904 EmitFunctionBodyStart();
906 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
908 // Print out code for the function.
909 bool HasAnyRealCode = false;
910 for (auto &MBB : *MF) {
911 // Print a label for the basic block.
912 EmitBasicBlockStart(MBB);
913 for (auto &MI : MBB) {
915 // Print the assembly for the instruction.
916 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
917 !MI.isDebugValue()) {
918 HasAnyRealCode = true;
922 if (ShouldPrintDebugScopes) {
923 for (const HandlerInfo &HI : Handlers) {
924 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
925 TimePassesIsEnabled);
926 HI.Handler->beginInstruction(&MI);
931 emitComments(MI, OutStreamer->GetCommentOS());
933 switch (MI.getOpcode()) {
934 case TargetOpcode::CFI_INSTRUCTION:
935 emitCFIInstruction(MI);
938 case TargetOpcode::LOCAL_ESCAPE:
942 case TargetOpcode::EH_LABEL:
943 case TargetOpcode::GC_LABEL:
944 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
946 case TargetOpcode::INLINEASM:
949 case TargetOpcode::DBG_VALUE:
951 if (!emitDebugValueComment(&MI, *this))
952 EmitInstruction(&MI);
955 case TargetOpcode::IMPLICIT_DEF:
956 if (isVerbose()) emitImplicitDef(&MI);
958 case TargetOpcode::KILL:
959 if (isVerbose()) emitKill(&MI, *this);
962 EmitInstruction(&MI);
966 if (ShouldPrintDebugScopes) {
967 for (const HandlerInfo &HI : Handlers) {
968 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
969 TimePassesIsEnabled);
970 HI.Handler->endInstruction();
975 EmitBasicBlockEnd(MBB);
978 // If the function is empty and the object file uses .subsections_via_symbols,
979 // then we need to emit *something* to the function body to prevent the
980 // labels from collapsing together. Just emit a noop.
981 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
983 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
984 OutStreamer->AddComment("avoids zero-length function");
986 // Targets can opt-out of emitting the noop here by leaving the opcode
988 if (Noop.getOpcode())
989 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
992 const Function *F = MF->getFunction();
993 for (const auto &BB : *F) {
994 if (!BB.hasAddressTaken())
996 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
997 if (Sym->isDefined())
999 OutStreamer->AddComment("Address of block that was removed by CodeGen");
1000 OutStreamer->EmitLabel(Sym);
1003 // Emit target-specific gunk after the function body.
1004 EmitFunctionBodyEnd();
1006 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1007 MMI->hasEHFunclets() || MAI->hasDotTypeDotSizeDirective()) {
1008 // Create a symbol for the end of function.
1009 CurrentFnEnd = createTempSymbol("func_end");
1010 OutStreamer->EmitLabel(CurrentFnEnd);
1013 // If the target wants a .size directive for the size of the function, emit
1015 if (MAI->hasDotTypeDotSizeDirective()) {
1016 // We can get the size as difference between the function label and the
1018 const MCExpr *SizeExp = MCBinaryExpr::createSub(
1019 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1020 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1021 if (auto Sym = dyn_cast<MCSymbolELF>(CurrentFnSym))
1022 OutStreamer->emitELFSize(Sym, SizeExp);
1025 for (const HandlerInfo &HI : Handlers) {
1026 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
1027 HI.Handler->markFunctionEnd();
1030 // Print out jump tables referenced by the function.
1031 EmitJumpTableInfo();
1033 // Emit post-function debug and/or EH information.
1034 for (const HandlerInfo &HI : Handlers) {
1035 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
1036 HI.Handler->endFunction(MF);
1040 OutStreamer->AddBlankLine();
1043 /// \brief Compute the number of Global Variables that uses a Constant.
1044 static unsigned getNumGlobalVariableUses(const Constant *C) {
1048 if (isa<GlobalVariable>(C))
1051 unsigned NumUses = 0;
1052 for (auto *CU : C->users())
1053 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1058 /// \brief Only consider global GOT equivalents if at least one user is a
1059 /// cstexpr inside an initializer of another global variables. Also, don't
1060 /// handle cstexpr inside instructions. During global variable emission,
1061 /// candidates are skipped and are emitted later in case at least one cstexpr
1062 /// isn't replaced by a PC relative GOT entry access.
1063 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1064 unsigned &NumGOTEquivUsers) {
1065 // Global GOT equivalents are unnamed private globals with a constant
1066 // pointer initializer to another global symbol. They must point to a
1067 // GlobalVariable or Function, i.e., as GlobalValue.
1068 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
1069 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
1072 // To be a got equivalent, at least one of its users need to be a constant
1073 // expression used by another global variable.
1074 for (auto *U : GV->users())
1075 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1077 return NumGOTEquivUsers > 0;
1080 /// \brief Unnamed constant global variables solely contaning a pointer to
1081 /// another globals variable is equivalent to a GOT table entry; it contains the
1082 /// the address of another symbol. Optimize it and replace accesses to these
1083 /// "GOT equivalents" by using the GOT entry for the final global instead.
1084 /// Compute GOT equivalent candidates among all global variables to avoid
1085 /// emitting them if possible later on, after it use is replaced by a GOT entry
1087 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1088 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1091 for (const auto &G : M.globals()) {
1092 unsigned NumGOTEquivUsers = 0;
1093 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1096 const MCSymbol *GOTEquivSym = getSymbol(&G);
1097 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1101 /// \brief Constant expressions using GOT equivalent globals may not be eligible
1102 /// for PC relative GOT entry conversion, in such cases we need to emit such
1103 /// globals we previously omitted in EmitGlobalVariable.
1104 void AsmPrinter::emitGlobalGOTEquivs() {
1105 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1108 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1109 for (auto &I : GlobalGOTEquivs) {
1110 const GlobalVariable *GV = I.second.first;
1111 unsigned Cnt = I.second.second;
1113 FailedCandidates.push_back(GV);
1115 GlobalGOTEquivs.clear();
1117 for (auto *GV : FailedCandidates)
1118 EmitGlobalVariable(GV);
1121 bool AsmPrinter::doFinalization(Module &M) {
1122 // Set the MachineFunction to nullptr so that we can catch attempted
1123 // accesses to MF specific features at the module level and so that
1124 // we can conditionalize accesses based on whether or not it is nullptr.
1127 // Gather all GOT equivalent globals in the module. We really need two
1128 // passes over the globals: one to compute and another to avoid its emission
1129 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1130 // where the got equivalent shows up before its use.
1131 computeGlobalGOTEquivs(M);
1133 // Emit global variables.
1134 for (const auto &G : M.globals())
1135 EmitGlobalVariable(&G);
1137 // Emit remaining GOT equivalent globals.
1138 emitGlobalGOTEquivs();
1140 // Emit visibility info for declarations
1141 for (const Function &F : M) {
1142 if (!F.isDeclarationForLinker())
1144 GlobalValue::VisibilityTypes V = F.getVisibility();
1145 if (V == GlobalValue::DefaultVisibility)
1148 MCSymbol *Name = getSymbol(&F);
1149 EmitVisibility(Name, V, false);
1152 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1154 // Emit module flags.
1155 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1156 M.getModuleFlagsMetadata(ModuleFlags);
1157 if (!ModuleFlags.empty())
1158 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, *Mang, TM);
1160 if (TM.getTargetTriple().isOSBinFormatELF()) {
1161 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1163 // Output stubs for external and common global variables.
1164 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1165 if (!Stubs.empty()) {
1166 OutStreamer->SwitchSection(TLOF.getDataSection());
1167 const DataLayout &DL = M.getDataLayout();
1169 for (const auto &Stub : Stubs) {
1170 OutStreamer->EmitLabel(Stub.first);
1171 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1172 DL.getPointerSize());
1177 // Finalize debug and EH information.
1178 for (const HandlerInfo &HI : Handlers) {
1179 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
1180 TimePassesIsEnabled);
1181 HI.Handler->endModule();
1187 // If the target wants to know about weak references, print them all.
1188 if (MAI->getWeakRefDirective()) {
1189 // FIXME: This is not lazy, it would be nice to only print weak references
1190 // to stuff that is actually used. Note that doing so would require targets
1191 // to notice uses in operands (due to constant exprs etc). This should
1192 // happen with the MC stuff eventually.
1194 // Print out module-level global variables here.
1195 for (const auto &G : M.globals()) {
1196 if (!G.hasExternalWeakLinkage())
1198 OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
1201 for (const auto &F : M) {
1202 if (!F.hasExternalWeakLinkage())
1204 OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1208 OutStreamer->AddBlankLine();
1209 for (const auto &Alias : M.aliases()) {
1210 MCSymbol *Name = getSymbol(&Alias);
1212 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1213 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1214 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1215 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1217 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1219 // Set the symbol type to function if the alias has a function type.
1220 // This affects codegen when the aliasee is not a function.
1221 if (Alias.getType()->getPointerElementType()->isFunctionTy())
1222 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
1224 EmitVisibility(Name, Alias.getVisibility());
1226 // Emit the directives as assignments aka .set:
1227 OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1229 // If the aliasee does not correspond to a symbol in the output, i.e. the
1230 // alias is not of an object or the aliased object is private, then set the
1231 // size of the alias symbol from the type of the alias. We don't do this in
1232 // other situations as the alias and aliasee having differing types but same
1233 // size may be intentional.
1234 const GlobalObject *BaseObject = Alias.getBaseObject();
1235 if (MAI->hasDotTypeDotSizeDirective() && Alias.getValueType()->isSized() &&
1236 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1237 const DataLayout &DL = M.getDataLayout();
1238 uint64_t Size = DL.getTypeAllocSize(Alias.getValueType());
1239 OutStreamer->emitELFSize(cast<MCSymbolELF>(Name),
1240 MCConstantExpr::create(Size, OutContext));
1244 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1245 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1246 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1247 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1248 MP->finishAssembly(M, *MI, *this);
1250 // Emit llvm.ident metadata in an '.ident' directive.
1251 EmitModuleIdents(M);
1253 // Emit __morestack address if needed for indirect calls.
1254 if (MMI->usesMorestackAddr()) {
1255 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1256 getDataLayout(), SectionKind::getReadOnly(),
1258 OutStreamer->SwitchSection(ReadOnlySection);
1260 MCSymbol *AddrSymbol =
1261 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1262 OutStreamer->EmitLabel(AddrSymbol);
1264 unsigned PtrSize = M.getDataLayout().getPointerSize(0);
1265 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1269 // If we don't have any trampolines, then we don't require stack memory
1270 // to be executable. Some targets have a directive to declare this.
1271 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1272 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1273 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1274 OutStreamer->SwitchSection(S);
1276 // Allow the target to emit any magic that it wants at the end of the file,
1277 // after everything else has gone out.
1278 EmitEndOfAsmFile(M);
1280 delete Mang; Mang = nullptr;
1283 OutStreamer->Finish();
1284 OutStreamer->reset();
1289 MCSymbol *AsmPrinter::getCurExceptionSym() {
1290 if (!CurExceptionSym)
1291 CurExceptionSym = createTempSymbol("exception");
1292 return CurExceptionSym;
1295 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1297 // Get the function symbol.
1298 CurrentFnSym = getSymbol(MF.getFunction());
1299 CurrentFnSymForSize = CurrentFnSym;
1300 CurrentFnBegin = nullptr;
1301 CurExceptionSym = nullptr;
1302 bool NeedsLocalForSize = MAI->needsLocalForSize();
1303 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1304 MMI->hasEHFunclets() || NeedsLocalForSize) {
1305 CurrentFnBegin = createTempSymbol("func_begin");
1306 if (NeedsLocalForSize)
1307 CurrentFnSymForSize = CurrentFnBegin;
1311 LI = &getAnalysis<MachineLoopInfo>();
1315 // Keep track the alignment, constpool entries per Section.
1319 SmallVector<unsigned, 4> CPEs;
1320 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1324 /// EmitConstantPool - Print to the current output stream assembly
1325 /// representations of the constants in the constant pool MCP. This is
1326 /// used to print out constants which have been "spilled to memory" by
1327 /// the code generator.
1329 void AsmPrinter::EmitConstantPool() {
1330 const MachineConstantPool *MCP = MF->getConstantPool();
1331 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1332 if (CP.empty()) return;
1334 // Calculate sections for constant pool entries. We collect entries to go into
1335 // the same section together to reduce amount of section switch statements.
1336 SmallVector<SectionCPs, 4> CPSections;
1337 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1338 const MachineConstantPoolEntry &CPE = CP[i];
1339 unsigned Align = CPE.getAlignment();
1341 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1343 const Constant *C = nullptr;
1344 if (!CPE.isMachineConstantPoolEntry())
1345 C = CPE.Val.ConstVal;
1348 getObjFileLowering().getSectionForConstant(getDataLayout(), Kind, C);
1350 // The number of sections are small, just do a linear search from the
1351 // last section to the first.
1353 unsigned SecIdx = CPSections.size();
1354 while (SecIdx != 0) {
1355 if (CPSections[--SecIdx].S == S) {
1361 SecIdx = CPSections.size();
1362 CPSections.push_back(SectionCPs(S, Align));
1365 if (Align > CPSections[SecIdx].Alignment)
1366 CPSections[SecIdx].Alignment = Align;
1367 CPSections[SecIdx].CPEs.push_back(i);
1370 // Now print stuff into the calculated sections.
1371 const MCSection *CurSection = nullptr;
1372 unsigned Offset = 0;
1373 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1374 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1375 unsigned CPI = CPSections[i].CPEs[j];
1376 MCSymbol *Sym = GetCPISymbol(CPI);
1377 if (!Sym->isUndefined())
1380 if (CurSection != CPSections[i].S) {
1381 OutStreamer->SwitchSection(CPSections[i].S);
1382 EmitAlignment(Log2_32(CPSections[i].Alignment));
1383 CurSection = CPSections[i].S;
1387 MachineConstantPoolEntry CPE = CP[CPI];
1389 // Emit inter-object padding for alignment.
1390 unsigned AlignMask = CPE.getAlignment() - 1;
1391 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1392 OutStreamer->EmitZeros(NewOffset - Offset);
1394 Type *Ty = CPE.getType();
1395 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1397 OutStreamer->EmitLabel(Sym);
1398 if (CPE.isMachineConstantPoolEntry())
1399 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1401 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1406 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1407 /// by the current function to the current output stream.
1409 void AsmPrinter::EmitJumpTableInfo() {
1410 const DataLayout &DL = MF->getDataLayout();
1411 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1413 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1414 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1415 if (JT.empty()) return;
1417 // Pick the directive to use to print the jump table entries, and switch to
1418 // the appropriate section.
1419 const Function *F = MF->getFunction();
1420 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1421 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1422 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1424 if (JTInDiffSection) {
1425 // Drop it in the readonly section.
1426 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(*F, *Mang, TM);
1427 OutStreamer->SwitchSection(ReadOnlySection);
1430 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1432 // Jump tables in code sections are marked with a data_region directive
1433 // where that's supported.
1434 if (!JTInDiffSection)
1435 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1437 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1438 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1440 // If this jump table was deleted, ignore it.
1441 if (JTBBs.empty()) continue;
1443 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1444 /// emit a .set directive for each unique entry.
1445 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1446 MAI->doesSetDirectiveSuppressesReloc()) {
1447 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1448 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1449 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1450 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1451 const MachineBasicBlock *MBB = JTBBs[ii];
1452 if (!EmittedSets.insert(MBB).second)
1455 // .set LJTSet, LBB32-base
1457 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1458 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1459 MCBinaryExpr::createSub(LHS, Base,
1464 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1465 // before each jump table. The first label is never referenced, but tells
1466 // the assembler and linker the extents of the jump table object. The
1467 // second label is actually referenced by the code.
1468 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1469 // FIXME: This doesn't have to have any specific name, just any randomly
1470 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1471 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1473 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1475 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1476 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1478 if (!JTInDiffSection)
1479 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1482 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1484 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1485 const MachineBasicBlock *MBB,
1486 unsigned UID) const {
1487 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1488 const MCExpr *Value = nullptr;
1489 switch (MJTI->getEntryKind()) {
1490 case MachineJumpTableInfo::EK_Inline:
1491 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1492 case MachineJumpTableInfo::EK_Custom32:
1493 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1494 MJTI, MBB, UID, OutContext);
1496 case MachineJumpTableInfo::EK_BlockAddress:
1497 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1499 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1501 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1502 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1503 // with a relocation as gp-relative, e.g.:
1505 MCSymbol *MBBSym = MBB->getSymbol();
1506 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1510 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1511 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1512 // with a relocation as gp-relative, e.g.:
1514 MCSymbol *MBBSym = MBB->getSymbol();
1515 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1519 case MachineJumpTableInfo::EK_LabelDifference32: {
1520 // Each entry is the address of the block minus the address of the jump
1521 // table. This is used for PIC jump tables where gprel32 is not supported.
1523 // .word LBB123 - LJTI1_2
1524 // If the .set directive avoids relocations, this is emitted as:
1525 // .set L4_5_set_123, LBB123 - LJTI1_2
1526 // .word L4_5_set_123
1527 if (MAI->doesSetDirectiveSuppressesReloc()) {
1528 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1532 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1533 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1534 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1535 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1540 assert(Value && "Unknown entry kind!");
1542 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1543 OutStreamer->EmitValue(Value, EntrySize);
1547 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1548 /// special global used by LLVM. If so, emit it and return true, otherwise
1549 /// do nothing and return false.
1550 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1551 if (GV->getName() == "llvm.used") {
1552 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1553 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1557 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1558 if (StringRef(GV->getSection()) == "llvm.metadata" ||
1559 GV->hasAvailableExternallyLinkage())
1562 if (!GV->hasAppendingLinkage()) return false;
1564 assert(GV->hasInitializer() && "Not a special LLVM global!");
1566 if (GV->getName() == "llvm.global_ctors") {
1567 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1570 if (TM.getRelocationModel() == Reloc::Static &&
1571 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1572 StringRef Sym(".constructors_used");
1573 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1579 if (GV->getName() == "llvm.global_dtors") {
1580 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1581 /* isCtor */ false);
1583 if (TM.getRelocationModel() == Reloc::Static &&
1584 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1585 StringRef Sym(".destructors_used");
1586 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1595 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1596 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1597 /// is true, as being used with this directive.
1598 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1599 // Should be an array of 'i8*'.
1600 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1601 const GlobalValue *GV =
1602 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1604 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1610 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
1612 llvm::Constant *Func;
1613 llvm::GlobalValue *ComdatKey;
1617 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1619 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1621 // Should be an array of '{ int, void ()* }' structs. The first value is the
1623 if (!isa<ConstantArray>(List)) return;
1625 // Sanity check the structors list.
1626 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1627 if (!InitList) return; // Not an array!
1628 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1629 // FIXME: Only allow the 3-field form in LLVM 4.0.
1630 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1631 return; // Not an array of two or three elements!
1632 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1633 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1634 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1635 return; // Not (int, ptr, ptr).
1637 // Gather the structors in a form that's convenient for sorting by priority.
1638 SmallVector<Structor, 8> Structors;
1639 for (Value *O : InitList->operands()) {
1640 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1641 if (!CS) continue; // Malformed.
1642 if (CS->getOperand(1)->isNullValue())
1643 break; // Found a null terminator, skip the rest.
1644 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1645 if (!Priority) continue; // Malformed.
1646 Structors.push_back(Structor());
1647 Structor &S = Structors.back();
1648 S.Priority = Priority->getLimitedValue(65535);
1649 S.Func = CS->getOperand(1);
1650 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1651 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1654 // Emit the function pointers in the target-specific order
1655 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1656 std::stable_sort(Structors.begin(), Structors.end(),
1657 [](const Structor &L,
1658 const Structor &R) { return L.Priority < R.Priority; });
1659 for (Structor &S : Structors) {
1660 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1661 const MCSymbol *KeySym = nullptr;
1662 if (GlobalValue *GV = S.ComdatKey) {
1663 if (GV->hasAvailableExternallyLinkage())
1664 // If the associated variable is available_externally, some other TU
1665 // will provide its dynamic initializer.
1668 KeySym = getSymbol(GV);
1670 MCSection *OutputSection =
1671 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1672 : Obj.getStaticDtorSection(S.Priority, KeySym));
1673 OutStreamer->SwitchSection(OutputSection);
1674 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1675 EmitAlignment(Align);
1676 EmitXXStructor(DL, S.Func);
1680 void AsmPrinter::EmitModuleIdents(Module &M) {
1681 if (!MAI->hasIdentDirective())
1684 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1685 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1686 const MDNode *N = NMD->getOperand(i);
1687 assert(N->getNumOperands() == 1 &&
1688 "llvm.ident metadata entry can have only one operand");
1689 const MDString *S = cast<MDString>(N->getOperand(0));
1690 OutStreamer->EmitIdent(S->getString());
1695 //===--------------------------------------------------------------------===//
1696 // Emission and print routines
1699 /// EmitInt8 - Emit a byte directive and value.
1701 void AsmPrinter::EmitInt8(int Value) const {
1702 OutStreamer->EmitIntValue(Value, 1);
1705 /// EmitInt16 - Emit a short directive and value.
1707 void AsmPrinter::EmitInt16(int Value) const {
1708 OutStreamer->EmitIntValue(Value, 2);
1711 /// EmitInt32 - Emit a long directive and value.
1713 void AsmPrinter::EmitInt32(int Value) const {
1714 OutStreamer->EmitIntValue(Value, 4);
1717 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1718 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1719 /// .set if it avoids relocations.
1720 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1721 unsigned Size) const {
1722 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
1725 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1726 /// where the size in bytes of the directive is specified by Size and Label
1727 /// specifies the label. This implicitly uses .set if it is available.
1728 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1730 bool IsSectionRelative) const {
1731 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1732 OutStreamer->EmitCOFFSecRel32(Label);
1736 // Emit Label+Offset (or just Label if Offset is zero)
1737 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
1739 Expr = MCBinaryExpr::createAdd(
1740 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
1742 OutStreamer->EmitValue(Expr, Size);
1745 //===----------------------------------------------------------------------===//
1747 // EmitAlignment - Emit an alignment directive to the specified power of
1748 // two boundary. For example, if you pass in 3 here, you will get an 8
1749 // byte alignment. If a global value is specified, and if that global has
1750 // an explicit alignment requested, it will override the alignment request
1751 // if required for correctness.
1753 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1755 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
1757 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1760 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1761 "undefined behavior");
1762 if (getCurrentSection()->getKind().isText())
1763 OutStreamer->EmitCodeAlignment(1u << NumBits);
1765 OutStreamer->EmitValueToAlignment(1u << NumBits);
1768 //===----------------------------------------------------------------------===//
1769 // Constant emission.
1770 //===----------------------------------------------------------------------===//
1772 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1773 MCContext &Ctx = OutContext;
1775 if (CV->isNullValue() || isa<UndefValue>(CV))
1776 return MCConstantExpr::create(0, Ctx);
1778 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1779 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
1781 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1782 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
1784 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1785 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
1787 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1789 llvm_unreachable("Unknown constant value to lower!");
1792 if (const MCExpr *RelocExpr
1793 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1796 switch (CE->getOpcode()) {
1798 // If the code isn't optimized, there may be outstanding folding
1799 // opportunities. Attempt to fold the expression using DataLayout as a
1800 // last resort before giving up.
1801 if (Constant *C = ConstantFoldConstantExpression(CE, getDataLayout()))
1803 return lowerConstant(C);
1805 // Otherwise report the problem to the user.
1808 raw_string_ostream OS(S);
1809 OS << "Unsupported expression in static initializer: ";
1810 CE->printAsOperand(OS, /*PrintType=*/false,
1811 !MF ? nullptr : MF->getFunction()->getParent());
1812 report_fatal_error(OS.str());
1814 case Instruction::GetElementPtr: {
1815 // Generate a symbolic expression for the byte address
1816 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
1817 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
1819 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1823 int64_t Offset = OffsetAI.getSExtValue();
1824 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
1828 case Instruction::Trunc:
1829 // We emit the value and depend on the assembler to truncate the generated
1830 // expression properly. This is important for differences between
1831 // blockaddress labels. Since the two labels are in the same function, it
1832 // is reasonable to treat their delta as a 32-bit value.
1834 case Instruction::BitCast:
1835 return lowerConstant(CE->getOperand(0));
1837 case Instruction::IntToPtr: {
1838 const DataLayout &DL = getDataLayout();
1840 // Handle casts to pointers by changing them into casts to the appropriate
1841 // integer type. This promotes constant folding and simplifies this code.
1842 Constant *Op = CE->getOperand(0);
1843 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1845 return lowerConstant(Op);
1848 case Instruction::PtrToInt: {
1849 const DataLayout &DL = getDataLayout();
1851 // Support only foldable casts to/from pointers that can be eliminated by
1852 // changing the pointer to the appropriately sized integer type.
1853 Constant *Op = CE->getOperand(0);
1854 Type *Ty = CE->getType();
1856 const MCExpr *OpExpr = lowerConstant(Op);
1858 // We can emit the pointer value into this slot if the slot is an
1859 // integer slot equal to the size of the pointer.
1860 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1863 // Otherwise the pointer is smaller than the resultant integer, mask off
1864 // the high bits so we are sure to get a proper truncation if the input is
1866 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1867 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
1868 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
1871 // The MC library also has a right-shift operator, but it isn't consistently
1872 // signed or unsigned between different targets.
1873 case Instruction::Add:
1874 case Instruction::Sub:
1875 case Instruction::Mul:
1876 case Instruction::SDiv:
1877 case Instruction::SRem:
1878 case Instruction::Shl:
1879 case Instruction::And:
1880 case Instruction::Or:
1881 case Instruction::Xor: {
1882 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1883 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1884 switch (CE->getOpcode()) {
1885 default: llvm_unreachable("Unknown binary operator constant cast expr");
1886 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
1887 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
1888 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
1889 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
1890 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
1891 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
1892 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
1893 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
1894 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
1900 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
1902 const Constant *BaseCV = nullptr,
1903 uint64_t Offset = 0);
1905 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
1907 /// isRepeatedByteSequence - Determine whether the given value is
1908 /// composed of a repeated sequence of identical bytes and return the
1909 /// byte value. If it is not a repeated sequence, return -1.
1910 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1911 StringRef Data = V->getRawDataValues();
1912 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1914 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1915 if (Data[i] != C) return -1;
1916 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1920 /// isRepeatedByteSequence - Determine whether the given value is
1921 /// composed of a repeated sequence of identical bytes and return the
1922 /// byte value. If it is not a repeated sequence, return -1.
1923 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
1924 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1925 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
1926 assert(Size % 8 == 0);
1928 // Extend the element to take zero padding into account.
1929 APInt Value = CI->getValue().zextOrSelf(Size);
1930 if (!Value.isSplat(8))
1933 return Value.zextOrTrunc(8).getZExtValue();
1935 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1936 // Make sure all array elements are sequences of the same repeated
1938 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1939 Constant *Op0 = CA->getOperand(0);
1940 int Byte = isRepeatedByteSequence(Op0, DL);
1944 // All array elements must be equal.
1945 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
1946 if (CA->getOperand(i) != Op0)
1951 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1952 return isRepeatedByteSequence(CDS);
1957 static void emitGlobalConstantDataSequential(const DataLayout &DL,
1958 const ConstantDataSequential *CDS,
1961 // See if we can aggregate this into a .fill, if so, emit it as such.
1962 int Value = isRepeatedByteSequence(CDS, DL);
1964 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
1965 // Don't emit a 1-byte object as a .fill.
1967 return AP.OutStreamer->EmitFill(Bytes, Value);
1970 // If this can be emitted with .ascii/.asciz, emit it as such.
1971 if (CDS->isString())
1972 return AP.OutStreamer->EmitBytes(CDS->getAsString());
1974 // Otherwise, emit the values in successive locations.
1975 unsigned ElementByteSize = CDS->getElementByteSize();
1976 if (isa<IntegerType>(CDS->getElementType())) {
1977 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1979 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
1980 CDS->getElementAsInteger(i));
1981 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
1985 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I)
1986 emitGlobalConstantFP(cast<ConstantFP>(CDS->getElementAsConstant(I)), AP);
1989 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1990 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1991 CDS->getNumElements();
1992 if (unsigned Padding = Size - EmittedSize)
1993 AP.OutStreamer->EmitZeros(Padding);
1997 static void emitGlobalConstantArray(const DataLayout &DL,
1998 const ConstantArray *CA, AsmPrinter &AP,
1999 const Constant *BaseCV, uint64_t Offset) {
2000 // See if we can aggregate some values. Make sure it can be
2001 // represented as a series of bytes of the constant value.
2002 int Value = isRepeatedByteSequence(CA, DL);
2005 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2006 AP.OutStreamer->EmitFill(Bytes, Value);
2009 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2010 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2011 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2016 static void emitGlobalConstantVector(const DataLayout &DL,
2017 const ConstantVector *CV, AsmPrinter &AP) {
2018 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2019 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2021 unsigned Size = DL.getTypeAllocSize(CV->getType());
2022 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2023 CV->getType()->getNumElements();
2024 if (unsigned Padding = Size - EmittedSize)
2025 AP.OutStreamer->EmitZeros(Padding);
2028 static void emitGlobalConstantStruct(const DataLayout &DL,
2029 const ConstantStruct *CS, AsmPrinter &AP,
2030 const Constant *BaseCV, uint64_t Offset) {
2031 // Print the fields in successive locations. Pad to align if needed!
2032 unsigned Size = DL.getTypeAllocSize(CS->getType());
2033 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2034 uint64_t SizeSoFar = 0;
2035 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2036 const Constant *Field = CS->getOperand(i);
2038 // Print the actual field value.
2039 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2041 // Check if padding is needed and insert one or more 0s.
2042 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2043 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2044 - Layout->getElementOffset(i)) - FieldSize;
2045 SizeSoFar += FieldSize + PadSize;
2047 // Insert padding - this may include padding to increase the size of the
2048 // current field up to the ABI size (if the struct is not packed) as well
2049 // as padding to ensure that the next field starts at the right offset.
2050 AP.OutStreamer->EmitZeros(PadSize);
2052 assert(SizeSoFar == Layout->getSizeInBytes() &&
2053 "Layout of constant struct may be incorrect!");
2056 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2057 APInt API = CFP->getValueAPF().bitcastToAPInt();
2059 // First print a comment with what we think the original floating-point value
2060 // should have been.
2061 if (AP.isVerbose()) {
2062 SmallString<8> StrVal;
2063 CFP->getValueAPF().toString(StrVal);
2066 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
2068 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2069 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2072 // Now iterate through the APInt chunks, emitting them in endian-correct
2073 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2075 unsigned NumBytes = API.getBitWidth() / 8;
2076 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2077 const uint64_t *p = API.getRawData();
2079 // PPC's long double has odd notions of endianness compared to how LLVM
2080 // handles it: p[0] goes first for *big* endian on PPC.
2081 if (AP.getDataLayout().isBigEndian() && !CFP->getType()->isPPC_FP128Ty()) {
2082 int Chunk = API.getNumWords() - 1;
2085 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2087 for (; Chunk >= 0; --Chunk)
2088 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2091 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2092 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2095 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2098 // Emit the tail padding for the long double.
2099 const DataLayout &DL = AP.getDataLayout();
2100 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2101 DL.getTypeStoreSize(CFP->getType()));
2104 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2105 const DataLayout &DL = AP.getDataLayout();
2106 unsigned BitWidth = CI->getBitWidth();
2108 // Copy the value as we may massage the layout for constants whose bit width
2109 // is not a multiple of 64-bits.
2110 APInt Realigned(CI->getValue());
2111 uint64_t ExtraBits = 0;
2112 unsigned ExtraBitsSize = BitWidth & 63;
2114 if (ExtraBitsSize) {
2115 // The bit width of the data is not a multiple of 64-bits.
2116 // The extra bits are expected to be at the end of the chunk of the memory.
2118 // * Nothing to be done, just record the extra bits to emit.
2120 // * Record the extra bits to emit.
2121 // * Realign the raw data to emit the chunks of 64-bits.
2122 if (DL.isBigEndian()) {
2123 // Basically the structure of the raw data is a chunk of 64-bits cells:
2124 // 0 1 BitWidth / 64
2125 // [chunk1][chunk2] ... [chunkN].
2126 // The most significant chunk is chunkN and it should be emitted first.
2127 // However, due to the alignment issue chunkN contains useless bits.
2128 // Realign the chunks so that they contain only useless information:
2129 // ExtraBits 0 1 (BitWidth / 64) - 1
2130 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2131 ExtraBits = Realigned.getRawData()[0] &
2132 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2133 Realigned = Realigned.lshr(ExtraBitsSize);
2135 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2138 // We don't expect assemblers to support integer data directives
2139 // for more than 64 bits, so we emit the data in at most 64-bit
2140 // quantities at a time.
2141 const uint64_t *RawData = Realigned.getRawData();
2142 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2143 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2144 AP.OutStreamer->EmitIntValue(Val, 8);
2147 if (ExtraBitsSize) {
2148 // Emit the extra bits after the 64-bits chunks.
2150 // Emit a directive that fills the expected size.
2151 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2152 Size -= (BitWidth / 64) * 8;
2153 assert(Size && Size * 8 >= ExtraBitsSize &&
2154 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2155 == ExtraBits && "Directive too small for extra bits.");
2156 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2160 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2161 /// equivalent global, by a target specific GOT pc relative access to the
2163 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2164 const Constant *BaseCst,
2166 // The global @foo below illustrates a global that uses a got equivalent.
2168 // @bar = global i32 42
2169 // @gotequiv = private unnamed_addr constant i32* @bar
2170 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2171 // i64 ptrtoint (i32* @foo to i64))
2174 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2175 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2178 // foo = cstexpr, where
2179 // cstexpr := <gotequiv> - "." + <cst>
2180 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2182 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2184 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2185 // gotpcrelcst := <offset from @foo base> + <cst>
2188 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2190 const MCSymbolRefExpr *SymA = MV.getSymA();
2194 // Check that GOT equivalent symbol is cached.
2195 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2196 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2199 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2203 // Check for a valid base symbol
2204 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2205 const MCSymbolRefExpr *SymB = MV.getSymB();
2207 if (!SymB || BaseSym != &SymB->getSymbol())
2210 // Make sure to match:
2212 // gotpcrelcst := <offset from @foo base> + <cst>
2214 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2215 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2216 // if the target knows how to encode it.
2218 int64_t GOTPCRelCst = Offset + MV.getConstant();
2219 if (GOTPCRelCst < 0)
2221 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2224 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2231 // .long gotequiv - "." + <cst>
2233 // is replaced by the target specific equivalent to:
2238 // .long bar@GOTPCREL+<gotpcrelcst>
2240 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2241 const GlobalVariable *GV = Result.first;
2242 int NumUses = (int)Result.second;
2243 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2244 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2245 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2246 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2248 // Update GOT equivalent usage information
2251 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2254 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2255 AsmPrinter &AP, const Constant *BaseCV,
2257 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2259 // Globals with sub-elements such as combinations of arrays and structs
2260 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2261 // constant symbol base and the current position with BaseCV and Offset.
2262 if (!BaseCV && CV->hasOneUse())
2263 BaseCV = dyn_cast<Constant>(CV->user_back());
2265 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2266 return AP.OutStreamer->EmitZeros(Size);
2268 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2275 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2276 CI->getZExtValue());
2277 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2280 emitGlobalConstantLargeInt(CI, AP);
2285 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2286 return emitGlobalConstantFP(CFP, AP);
2288 if (isa<ConstantPointerNull>(CV)) {
2289 AP.OutStreamer->EmitIntValue(0, Size);
2293 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2294 return emitGlobalConstantDataSequential(DL, CDS, AP);
2296 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2297 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2299 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2300 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2302 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2303 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2305 if (CE->getOpcode() == Instruction::BitCast)
2306 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2309 // If the constant expression's size is greater than 64-bits, then we have
2310 // to emit the value in chunks. Try to constant fold the value and emit it
2312 Constant *New = ConstantFoldConstantExpression(CE, DL);
2313 if (New && New != CE)
2314 return emitGlobalConstantImpl(DL, New, AP);
2318 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2319 return emitGlobalConstantVector(DL, V, AP);
2321 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2322 // thread the streamer with EmitValue.
2323 const MCExpr *ME = AP.lowerConstant(CV);
2325 // Since lowerConstant already folded and got rid of all IR pointer and
2326 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2328 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2329 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2331 AP.OutStreamer->EmitValue(ME, Size);
2334 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2335 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2336 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2338 emitGlobalConstantImpl(DL, CV, *this);
2339 else if (MAI->hasSubsectionsViaSymbols()) {
2340 // If the global has zero size, emit a single byte so that two labels don't
2341 // look like they are at the same location.
2342 OutStreamer->EmitIntValue(0, 1);
2346 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2347 // Target doesn't support this yet!
2348 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2351 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2353 OS << '+' << Offset;
2354 else if (Offset < 0)
2358 //===----------------------------------------------------------------------===//
2359 // Symbol Lowering Routines.
2360 //===----------------------------------------------------------------------===//
2362 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2363 return OutContext.createTempSymbol(Name, true);
2366 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2367 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2370 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2371 return MMI->getAddrLabelSymbol(BB);
2374 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2375 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2376 const DataLayout &DL = getDataLayout();
2377 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2378 "CPI" + Twine(getFunctionNumber()) + "_" +
2382 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2383 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2384 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2387 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2388 /// FIXME: privatize to AsmPrinter.
2389 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2390 const DataLayout &DL = getDataLayout();
2391 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2392 Twine(getFunctionNumber()) + "_" +
2393 Twine(UID) + "_set_" + Twine(MBBID));
2396 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2397 StringRef Suffix) const {
2398 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2402 /// Return the MCSymbol for the specified ExternalSymbol.
2403 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2404 SmallString<60> NameStr;
2405 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2406 return OutContext.getOrCreateSymbol(NameStr);
2411 /// PrintParentLoopComment - Print comments about parent loops of this one.
2412 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2413 unsigned FunctionNumber) {
2415 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2416 OS.indent(Loop->getLoopDepth()*2)
2417 << "Parent Loop BB" << FunctionNumber << "_"
2418 << Loop->getHeader()->getNumber()
2419 << " Depth=" << Loop->getLoopDepth() << '\n';
2423 /// PrintChildLoopComment - Print comments about child loops within
2424 /// the loop for this basic block, with nesting.
2425 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2426 unsigned FunctionNumber) {
2427 // Add child loop information
2428 for (const MachineLoop *CL : *Loop) {
2429 OS.indent(CL->getLoopDepth()*2)
2430 << "Child Loop BB" << FunctionNumber << "_"
2431 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2433 PrintChildLoopComment(OS, CL, FunctionNumber);
2437 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2438 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2439 const MachineLoopInfo *LI,
2440 const AsmPrinter &AP) {
2441 // Add loop depth information
2442 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2445 MachineBasicBlock *Header = Loop->getHeader();
2446 assert(Header && "No header for loop");
2448 // If this block is not a loop header, just print out what is the loop header
2450 if (Header != &MBB) {
2451 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2452 Twine(AP.getFunctionNumber())+"_" +
2453 Twine(Loop->getHeader()->getNumber())+
2454 " Depth="+Twine(Loop->getLoopDepth()));
2458 // Otherwise, it is a loop header. Print out information about child and
2460 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2462 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2465 OS.indent(Loop->getLoopDepth()*2-2);
2470 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2472 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2476 /// EmitBasicBlockStart - This method prints the label for the specified
2477 /// MachineBasicBlock, an alignment (if present) and a comment describing
2478 /// it if appropriate.
2479 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2480 // End the previous funclet and start a new one.
2481 if (MBB.isEHFuncletEntry()) {
2482 for (const HandlerInfo &HI : Handlers) {
2483 HI.Handler->endFunclet();
2484 HI.Handler->beginFunclet(MBB);
2488 // Emit an alignment directive for this block, if needed.
2489 if (unsigned Align = MBB.getAlignment())
2490 EmitAlignment(Align);
2492 // If the block has its address taken, emit any labels that were used to
2493 // reference the block. It is possible that there is more than one label
2494 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2495 // the references were generated.
2496 if (MBB.hasAddressTaken()) {
2497 const BasicBlock *BB = MBB.getBasicBlock();
2499 OutStreamer->AddComment("Block address taken");
2501 // MBBs can have their address taken as part of CodeGen without having
2502 // their corresponding BB's address taken in IR
2503 if (BB->hasAddressTaken())
2504 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2505 OutStreamer->EmitLabel(Sym);
2508 // Print some verbose block comments.
2510 if (const BasicBlock *BB = MBB.getBasicBlock()) {
2511 if (BB->hasName()) {
2512 BB->printAsOperand(OutStreamer->GetCommentOS(),
2513 /*PrintType=*/false, BB->getModule());
2514 OutStreamer->GetCommentOS() << '\n';
2517 emitBasicBlockLoopComments(MBB, LI, *this);
2520 // Print the main label for the block.
2521 if (MBB.pred_empty() ||
2522 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2524 // NOTE: Want this comment at start of line, don't emit with AddComment.
2525 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2528 OutStreamer->EmitLabel(MBB.getSymbol());
2532 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2533 bool IsDefinition) const {
2534 MCSymbolAttr Attr = MCSA_Invalid;
2536 switch (Visibility) {
2538 case GlobalValue::HiddenVisibility:
2540 Attr = MAI->getHiddenVisibilityAttr();
2542 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2544 case GlobalValue::ProtectedVisibility:
2545 Attr = MAI->getProtectedVisibilityAttr();
2549 if (Attr != MCSA_Invalid)
2550 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2553 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2554 /// exactly one predecessor and the control transfer mechanism between
2555 /// the predecessor and this block is a fall-through.
2557 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2558 // If this is a landing pad, it isn't a fall through. If it has no preds,
2559 // then nothing falls through to it.
2560 if (MBB->isEHPad() || MBB->pred_empty())
2563 // If there isn't exactly one predecessor, it can't be a fall through.
2564 if (MBB->pred_size() > 1)
2567 // The predecessor has to be immediately before this block.
2568 MachineBasicBlock *Pred = *MBB->pred_begin();
2569 if (!Pred->isLayoutSuccessor(MBB))
2572 // If the block is completely empty, then it definitely does fall through.
2576 // Check the terminators in the previous blocks
2577 for (const auto &MI : Pred->terminators()) {
2578 // If it is not a simple branch, we are in a table somewhere.
2579 if (!MI.isBranch() || MI.isIndirectBranch())
2582 // If we are the operands of one of the branches, this is not a fall
2583 // through. Note that targets with delay slots will usually bundle
2584 // terminators with the delay slot instruction.
2585 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2588 if (OP->isMBB() && OP->getMBB() == MBB)
2598 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2599 if (!S.usesMetadata())
2602 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2603 " stackmap formats, please see the documentation for a description of"
2604 " the default format. If you really need a custom serialized format,"
2605 " please file a bug");
2607 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2608 gcp_map_type::iterator GCPI = GCMap.find(&S);
2609 if (GCPI != GCMap.end())
2610 return GCPI->second.get();
2612 const char *Name = S.getName().c_str();
2614 for (GCMetadataPrinterRegistry::iterator
2615 I = GCMetadataPrinterRegistry::begin(),
2616 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2617 if (strcmp(Name, I->getName()) == 0) {
2618 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2620 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2621 return IterBool.first->second.get();
2624 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2627 /// Pin vtable to this file.
2628 AsmPrinterHandler::~AsmPrinterHandler() {}
2630 void AsmPrinterHandler::markFunctionEnd() {}