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 (TT.isOSDarwin()) {
196 unsigned Major, Minor, Update;
197 TT.getOSVersion(Major, Minor, Update);
198 // If there is a version specified, Major will be non-zero.
200 MCVersionMinType VersionType;
202 VersionType = MCVM_WatchOSVersionMin;
203 else if (TT.isTvOS())
204 VersionType = MCVM_TvOSVersionMin;
205 else if (TT.isMacOSX())
206 VersionType = MCVM_OSXVersionMin;
208 VersionType = MCVM_IOSVersionMin;
209 OutStreamer->EmitVersionMin(VersionType, Major, Minor, Update);
213 // Allow the target to emit any magic that it wants at the start of the file.
214 EmitStartOfAsmFile(M);
216 // Very minimal debug info. It is ignored if we emit actual debug info. If we
217 // don't, this at least helps the user find where a global came from.
218 if (MAI->hasSingleParameterDotFile()) {
220 OutStreamer->EmitFileDirective(M.getModuleIdentifier());
223 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
224 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
226 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
227 MP->beginAssembly(M, *MI, *this);
229 // Emit module-level inline asm if it exists.
230 if (!M.getModuleInlineAsm().empty()) {
231 // We're at the module level. Construct MCSubtarget from the default CPU
232 // and target triple.
233 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
234 TM.getTargetTriple().str(), TM.getTargetCPU(),
235 TM.getTargetFeatureString()));
236 OutStreamer->AddComment("Start of file scope inline assembly");
237 OutStreamer->AddBlankLine();
238 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
239 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
240 OutStreamer->AddComment("End of file scope inline assembly");
241 OutStreamer->AddBlankLine();
244 if (MAI->doesSupportDebugInformation()) {
245 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
246 if (EmitCodeView && TM.getTargetTriple().isKnownWindowsMSVCEnvironment()) {
247 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
249 CodeViewLineTablesGroupName));
251 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
252 DD = new DwarfDebug(this, &M);
253 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
257 EHStreamer *ES = nullptr;
258 switch (MAI->getExceptionHandlingType()) {
259 case ExceptionHandling::None:
261 case ExceptionHandling::SjLj:
262 case ExceptionHandling::DwarfCFI:
263 ES = new DwarfCFIException(this);
265 case ExceptionHandling::ARM:
266 ES = new ARMException(this);
268 case ExceptionHandling::WinEH:
269 switch (MAI->getWinEHEncodingType()) {
270 default: llvm_unreachable("unsupported unwinding information encoding");
271 case WinEH::EncodingType::Invalid:
273 case WinEH::EncodingType::X86:
274 case WinEH::EncodingType::Itanium:
275 ES = new WinException(this);
281 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
285 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
286 if (!MAI.hasWeakDefCanBeHiddenDirective())
289 return canBeOmittedFromSymbolTable(GV);
292 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
293 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
295 case GlobalValue::CommonLinkage:
296 case GlobalValue::LinkOnceAnyLinkage:
297 case GlobalValue::LinkOnceODRLinkage:
298 case GlobalValue::WeakAnyLinkage:
299 case GlobalValue::WeakODRLinkage:
300 if (MAI->hasWeakDefDirective()) {
302 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
304 if (!canBeHidden(GV, *MAI))
305 // .weak_definition _foo
306 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
308 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
309 } else if (MAI->hasLinkOnceDirective()) {
311 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
312 //NOTE: linkonce is handled by the section the symbol was assigned to.
315 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
318 case GlobalValue::AppendingLinkage:
319 // FIXME: appending linkage variables should go into a section of
320 // their name or something. For now, just emit them as external.
321 case GlobalValue::ExternalLinkage:
322 // If external or appending, declare as a global symbol.
324 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
326 case GlobalValue::PrivateLinkage:
327 case GlobalValue::InternalLinkage:
329 case GlobalValue::AvailableExternallyLinkage:
330 llvm_unreachable("Should never emit this");
331 case GlobalValue::ExternalWeakLinkage:
332 llvm_unreachable("Don't know how to emit these");
334 llvm_unreachable("Unknown linkage type!");
337 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
338 const GlobalValue *GV) const {
339 TM.getNameWithPrefix(Name, GV, *Mang);
342 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
343 return TM.getSymbol(GV, *Mang);
346 static MCSymbol *getOrCreateEmuTLSControlSym(MCSymbol *GVSym, MCContext &C) {
347 return C.getOrCreateSymbol(Twine("__emutls_v.") + GVSym->getName());
350 static MCSymbol *getOrCreateEmuTLSInitSym(MCSymbol *GVSym, MCContext &C) {
351 return C.getOrCreateSymbol(Twine("__emutls_t.") + GVSym->getName());
354 /// EmitEmulatedTLSControlVariable - Emit the control variable for an emulated TLS variable.
355 void AsmPrinter::EmitEmulatedTLSControlVariable(const GlobalVariable *GV,
356 MCSymbol *EmittedSym,
357 bool AllZeroInitValue) {
358 // If there is init value, use .data.rel.local section;
359 // otherwise use the .data section.
360 MCSection *TLSVarSection =
361 const_cast<MCSection *>((GV->hasInitializer() && !AllZeroInitValue)
362 ? getObjFileLowering().getDataRelSection()
363 : getObjFileLowering().getDataSection());
364 OutStreamer->SwitchSection(TLSVarSection);
365 MCSymbol *GVSym = getSymbol(GV);
366 EmitLinkage(GV, EmittedSym); // same linkage as GV
367 const DataLayout &DL = GV->getParent()->getDataLayout();
368 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
369 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
370 unsigned WordSize = DL.getPointerSize();
371 unsigned Alignment = DL.getPointerABIAlignment();
372 EmitAlignment(Log2_32(Alignment));
373 OutStreamer->EmitLabel(EmittedSym);
374 OutStreamer->EmitIntValue(Size, WordSize);
375 OutStreamer->EmitIntValue((1 << AlignLog), WordSize);
376 OutStreamer->EmitIntValue(0, WordSize);
377 if (GV->hasInitializer() && !AllZeroInitValue) {
378 OutStreamer->EmitSymbolValue(
379 getOrCreateEmuTLSInitSym(GVSym, OutContext), WordSize);
381 OutStreamer->EmitIntValue(0, WordSize);
382 if (MAI->hasDotTypeDotSizeDirective())
383 OutStreamer->emitELFSize(cast<MCSymbolELF>(EmittedSym),
384 MCConstantExpr::create(4 * WordSize, OutContext));
385 OutStreamer->AddBlankLine(); // End of the __emutls_v.* variable.
388 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
389 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
391 GV->getThreadLocalMode() != llvm::GlobalVariable::NotThreadLocal &&
392 TM.Options.EmulatedTLS;
393 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
394 "No emulated TLS variables in the common section");
396 if (GV->hasInitializer()) {
397 // Check to see if this is a special global used by LLVM, if so, emit it.
398 if (EmitSpecialLLVMGlobal(GV))
401 // Skip the emission of global equivalents. The symbol can be emitted later
402 // on by emitGlobalGOTEquivs in case it turns out to be needed.
403 if (GlobalGOTEquivs.count(getSymbol(GV)))
406 if (isVerbose() && !IsEmuTLSVar) {
407 // When printing the control variable __emutls_v.*,
408 // we don't need to print the original TLS variable name.
409 GV->printAsOperand(OutStreamer->GetCommentOS(),
410 /*PrintType=*/false, GV->getParent());
411 OutStreamer->GetCommentOS() << '\n';
415 MCSymbol *GVSym = getSymbol(GV);
416 MCSymbol *EmittedSym = IsEmuTLSVar ?
417 getOrCreateEmuTLSControlSym(GVSym, OutContext) : GVSym;
418 // getOrCreateEmuTLSControlSym only creates the symbol with name and default attributes.
419 // GV's or GVSym's attributes will be used for the EmittedSym.
421 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
423 if (!GV->hasInitializer()) // External globals require no extra code.
426 GVSym->redefineIfPossible();
427 if (GVSym->isDefined() || GVSym->isVariable())
428 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
429 "' is already defined");
431 if (MAI->hasDotTypeDotSizeDirective())
432 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
434 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
436 const DataLayout &DL = GV->getParent()->getDataLayout();
437 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
439 // If the alignment is specified, we *must* obey it. Overaligning a global
440 // with a specified alignment is a prompt way to break globals emitted to
441 // sections and expected to be contiguous (e.g. ObjC metadata).
442 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
444 bool AllZeroInitValue = false;
445 const Constant *InitValue = GV->getInitializer();
446 if (isa<ConstantAggregateZero>(InitValue))
447 AllZeroInitValue = true;
449 const ConstantInt *InitIntValue = dyn_cast<ConstantInt>(InitValue);
450 if (InitIntValue && InitIntValue->isZero())
451 AllZeroInitValue = true;
454 EmitEmulatedTLSControlVariable(GV, EmittedSym, AllZeroInitValue);
456 for (const HandlerInfo &HI : Handlers) {
457 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
458 HI.Handler->setSymbolSize(GVSym, Size);
461 // Handle common and BSS local symbols (.lcomm).
462 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
463 assert(!(IsEmuTLSVar && GVKind.isCommon()) &&
464 "No emulated TLS variables in the common section");
465 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
466 unsigned Align = 1 << AlignLog;
468 // Handle common symbols.
469 if (GVKind.isCommon()) {
470 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
474 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
478 // Handle local BSS symbols.
479 if (MAI->hasMachoZeroFillDirective()) {
480 MCSection *TheSection =
481 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
482 // .zerofill __DATA, __bss, _foo, 400, 5
483 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
487 // Use .lcomm only if it supports user-specified alignment.
488 // Otherwise, while it would still be correct to use .lcomm in some
489 // cases (e.g. when Align == 1), the external assembler might enfore
490 // some -unknown- default alignment behavior, which could cause
491 // spurious differences between external and integrated assembler.
492 // Prefer to simply fall back to .local / .comm in this case.
493 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
495 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
499 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
503 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
505 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
509 if (IsEmuTLSVar && AllZeroInitValue)
510 return; // No need of initialization values.
512 MCSymbol *EmittedInitSym = IsEmuTLSVar ?
513 getOrCreateEmuTLSInitSym(GVSym, OutContext) : GVSym;
514 // getOrCreateEmuTLSInitSym only creates the symbol with name and default attributes.
515 // GV's or GVSym's attributes will be used for the EmittedInitSym.
517 MCSection *TheSection = IsEmuTLSVar ?
518 getObjFileLowering().getReadOnlySection() :
519 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
521 // Handle the zerofill directive on darwin, which is a special form of BSS
523 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective() && !IsEmuTLSVar) {
524 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
527 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
528 // .zerofill __DATA, __common, _foo, 400, 5
529 OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
533 // Handle thread local data for mach-o which requires us to output an
534 // additional structure of data and mangle the original symbol so that we
535 // can reference it later.
537 // TODO: This should become an "emit thread local global" method on TLOF.
538 // All of this macho specific stuff should be sunk down into TLOFMachO and
539 // stuff like "TLSExtraDataSection" should no longer be part of the parent
540 // TLOF class. This will also make it more obvious that stuff like
541 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
543 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective() && !IsEmuTLSVar) {
544 // Emit the .tbss symbol
546 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
548 if (GVKind.isThreadBSS()) {
549 TheSection = getObjFileLowering().getTLSBSSSection();
550 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
551 } else if (GVKind.isThreadData()) {
552 OutStreamer->SwitchSection(TheSection);
554 EmitAlignment(AlignLog, GV);
555 OutStreamer->EmitLabel(MangSym);
557 EmitGlobalConstant(GV->getParent()->getDataLayout(),
558 GV->getInitializer());
561 OutStreamer->AddBlankLine();
563 // Emit the variable struct for the runtime.
564 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
566 OutStreamer->SwitchSection(TLVSect);
567 // Emit the linkage here.
568 EmitLinkage(GV, GVSym);
569 OutStreamer->EmitLabel(GVSym);
571 // Three pointers in size:
572 // - __tlv_bootstrap - used to make sure support exists
573 // - spare pointer, used when mapped by the runtime
574 // - pointer to mangled symbol above with initializer
575 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
576 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
578 OutStreamer->EmitIntValue(0, PtrSize);
579 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
581 OutStreamer->AddBlankLine();
585 OutStreamer->SwitchSection(TheSection);
587 // emutls_t.* symbols are only used in the current compilation unit.
589 EmitLinkage(GV, EmittedInitSym);
590 EmitAlignment(AlignLog, GV);
592 OutStreamer->EmitLabel(EmittedInitSym);
594 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
596 if (MAI->hasDotTypeDotSizeDirective())
598 OutStreamer->emitELFSize(cast<MCSymbolELF>(EmittedInitSym),
599 MCConstantExpr::create(Size, OutContext));
601 OutStreamer->AddBlankLine();
604 /// EmitFunctionHeader - This method emits the header for the current
606 void AsmPrinter::EmitFunctionHeader() {
607 // Print out constants referenced by the function
610 // Print the 'header' of function.
611 const Function *F = MF->getFunction();
613 OutStreamer->SwitchSection(
614 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
615 EmitVisibility(CurrentFnSym, F->getVisibility());
617 EmitLinkage(F, CurrentFnSym);
618 if (MAI->hasFunctionAlignment())
619 EmitAlignment(MF->getAlignment(), F);
621 if (MAI->hasDotTypeDotSizeDirective())
622 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
625 F->printAsOperand(OutStreamer->GetCommentOS(),
626 /*PrintType=*/false, F->getParent());
627 OutStreamer->GetCommentOS() << '\n';
630 // Emit the prefix data.
631 if (F->hasPrefixData())
632 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
634 // Emit the CurrentFnSym. This is a virtual function to allow targets to
635 // do their wild and crazy things as required.
636 EmitFunctionEntryLabel();
638 // If the function had address-taken blocks that got deleted, then we have
639 // references to the dangling symbols. Emit them at the start of the function
640 // so that we don't get references to undefined symbols.
641 std::vector<MCSymbol*> DeadBlockSyms;
642 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
643 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
644 OutStreamer->AddComment("Address taken block that was later removed");
645 OutStreamer->EmitLabel(DeadBlockSyms[i]);
648 if (CurrentFnBegin) {
649 if (MAI->useAssignmentForEHBegin()) {
650 MCSymbol *CurPos = OutContext.createTempSymbol();
651 OutStreamer->EmitLabel(CurPos);
652 OutStreamer->EmitAssignment(CurrentFnBegin,
653 MCSymbolRefExpr::create(CurPos, OutContext));
655 OutStreamer->EmitLabel(CurrentFnBegin);
659 // Emit pre-function debug and/or EH information.
660 for (const HandlerInfo &HI : Handlers) {
661 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
662 HI.Handler->beginFunction(MF);
665 // Emit the prologue data.
666 if (F->hasPrologueData())
667 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrologueData());
670 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
671 /// function. This can be overridden by targets as required to do custom stuff.
672 void AsmPrinter::EmitFunctionEntryLabel() {
673 CurrentFnSym->redefineIfPossible();
675 // The function label could have already been emitted if two symbols end up
676 // conflicting due to asm renaming. Detect this and emit an error.
677 if (CurrentFnSym->isVariable())
678 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
679 "' is a protected alias");
680 if (CurrentFnSym->isDefined())
681 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
682 "' label emitted multiple times to assembly file");
684 return OutStreamer->EmitLabel(CurrentFnSym);
687 /// emitComments - Pretty-print comments for instructions.
688 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
689 const MachineFunction *MF = MI.getParent()->getParent();
690 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
692 // Check for spills and reloads
695 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
697 // We assume a single instruction only has a spill or reload, not
699 const MachineMemOperand *MMO;
700 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
701 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
702 MMO = *MI.memoperands_begin();
703 CommentOS << MMO->getSize() << "-byte Reload\n";
705 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
706 if (FrameInfo->isSpillSlotObjectIndex(FI))
707 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
708 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
709 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
710 MMO = *MI.memoperands_begin();
711 CommentOS << MMO->getSize() << "-byte Spill\n";
713 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
714 if (FrameInfo->isSpillSlotObjectIndex(FI))
715 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
718 // Check for spill-induced copies
719 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
720 CommentOS << " Reload Reuse\n";
723 /// emitImplicitDef - This method emits the specified machine instruction
724 /// that is an implicit def.
725 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
726 unsigned RegNo = MI->getOperand(0).getReg();
728 SmallString<128> Str;
729 raw_svector_ostream OS(Str);
730 OS << "implicit-def: "
731 << PrintReg(RegNo, MF->getSubtarget().getRegisterInfo());
733 OutStreamer->AddComment(OS.str());
734 OutStreamer->AddBlankLine();
737 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
739 raw_string_ostream OS(Str);
741 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
742 const MachineOperand &Op = MI->getOperand(i);
743 assert(Op.isReg() && "KILL instruction must have only register operands");
745 << PrintReg(Op.getReg(),
746 AP.MF->getSubtarget().getRegisterInfo())
747 << (Op.isDef() ? "<def>" : "<kill>");
749 AP.OutStreamer->AddComment(Str);
750 AP.OutStreamer->AddBlankLine();
753 /// emitDebugValueComment - This method handles the target-independent form
754 /// of DBG_VALUE, returning true if it was able to do so. A false return
755 /// means the target will need to handle MI in EmitInstruction.
756 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
757 // This code handles only the 4-operand target-independent form.
758 if (MI->getNumOperands() != 4)
761 SmallString<128> Str;
762 raw_svector_ostream OS(Str);
763 OS << "DEBUG_VALUE: ";
765 const DILocalVariable *V = MI->getDebugVariable();
766 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
767 StringRef Name = SP->getDisplayName();
773 const DIExpression *Expr = MI->getDebugExpression();
774 if (Expr->isBitPiece())
775 OS << " [bit_piece offset=" << Expr->getBitPieceOffset()
776 << " size=" << Expr->getBitPieceSize() << "]";
779 // The second operand is only an offset if it's an immediate.
780 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
781 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
783 // Register or immediate value. Register 0 means undef.
784 if (MI->getOperand(0).isFPImm()) {
785 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
786 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
787 OS << (double)APF.convertToFloat();
788 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
789 OS << APF.convertToDouble();
791 // There is no good way to print long double. Convert a copy to
792 // double. Ah well, it's only a comment.
794 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
796 OS << "(long double) " << APF.convertToDouble();
798 } else if (MI->getOperand(0).isImm()) {
799 OS << MI->getOperand(0).getImm();
800 } else if (MI->getOperand(0).isCImm()) {
801 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
804 if (MI->getOperand(0).isReg()) {
805 Reg = MI->getOperand(0).getReg();
807 assert(MI->getOperand(0).isFI() && "Unknown operand type");
808 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
809 Offset += TFI->getFrameIndexReference(*AP.MF,
810 MI->getOperand(0).getIndex(), Reg);
814 // Suppress offset, it is not meaningful here.
816 // NOTE: Want this comment at start of line, don't emit with AddComment.
817 AP.OutStreamer->emitRawComment(OS.str());
822 OS << PrintReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
826 OS << '+' << Offset << ']';
828 // NOTE: Want this comment at start of line, don't emit with AddComment.
829 AP.OutStreamer->emitRawComment(OS.str());
833 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
834 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
835 MF->getFunction()->needsUnwindTableEntry())
838 if (MMI->hasDebugInfo())
844 bool AsmPrinter::needsSEHMoves() {
845 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
848 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
849 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
850 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
851 ExceptionHandlingType != ExceptionHandling::ARM)
854 if (needsCFIMoves() == CFI_M_None)
857 const MachineModuleInfo &MMI = MF->getMMI();
858 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
859 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
860 const MCCFIInstruction &CFI = Instrs[CFIIndex];
861 emitCFIInstruction(CFI);
864 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
865 // The operands are the MCSymbol and the frame offset of the allocation.
866 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
867 int FrameOffset = MI.getOperand(1).getImm();
869 // Emit a symbol assignment.
870 OutStreamer->EmitAssignment(FrameAllocSym,
871 MCConstantExpr::create(FrameOffset, OutContext));
874 /// EmitFunctionBody - This method emits the body and trailer for a
876 void AsmPrinter::EmitFunctionBody() {
877 EmitFunctionHeader();
879 // Emit target-specific gunk before the function body.
880 EmitFunctionBodyStart();
882 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
884 // Print out code for the function.
885 bool HasAnyRealCode = false;
886 for (auto &MBB : *MF) {
887 // Print a label for the basic block.
888 EmitBasicBlockStart(MBB);
889 for (auto &MI : MBB) {
891 // Print the assembly for the instruction.
892 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
893 !MI.isDebugValue()) {
894 HasAnyRealCode = true;
898 if (ShouldPrintDebugScopes) {
899 for (const HandlerInfo &HI : Handlers) {
900 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
901 TimePassesIsEnabled);
902 HI.Handler->beginInstruction(&MI);
907 emitComments(MI, OutStreamer->GetCommentOS());
909 switch (MI.getOpcode()) {
910 case TargetOpcode::CFI_INSTRUCTION:
911 emitCFIInstruction(MI);
914 case TargetOpcode::LOCAL_ESCAPE:
918 case TargetOpcode::EH_LABEL:
919 case TargetOpcode::GC_LABEL:
920 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
922 case TargetOpcode::INLINEASM:
925 case TargetOpcode::DBG_VALUE:
927 if (!emitDebugValueComment(&MI, *this))
928 EmitInstruction(&MI);
931 case TargetOpcode::IMPLICIT_DEF:
932 if (isVerbose()) emitImplicitDef(&MI);
934 case TargetOpcode::KILL:
935 if (isVerbose()) emitKill(&MI, *this);
938 EmitInstruction(&MI);
942 if (ShouldPrintDebugScopes) {
943 for (const HandlerInfo &HI : Handlers) {
944 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
945 TimePassesIsEnabled);
946 HI.Handler->endInstruction();
951 EmitBasicBlockEnd(MBB);
954 // If the function is empty and the object file uses .subsections_via_symbols,
955 // then we need to emit *something* to the function body to prevent the
956 // labels from collapsing together. Just emit a noop.
957 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
959 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
960 OutStreamer->AddComment("avoids zero-length function");
962 // Targets can opt-out of emitting the noop here by leaving the opcode
964 if (Noop.getOpcode())
965 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
968 const Function *F = MF->getFunction();
969 for (const auto &BB : *F) {
970 if (!BB.hasAddressTaken())
972 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
973 if (Sym->isDefined())
975 OutStreamer->AddComment("Address of block that was removed by CodeGen");
976 OutStreamer->EmitLabel(Sym);
979 // Emit target-specific gunk after the function body.
980 EmitFunctionBodyEnd();
982 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
983 MMI->hasEHFunclets() || MAI->hasDotTypeDotSizeDirective()) {
984 // Create a symbol for the end of function.
985 CurrentFnEnd = createTempSymbol("func_end");
986 OutStreamer->EmitLabel(CurrentFnEnd);
989 // If the target wants a .size directive for the size of the function, emit
991 if (MAI->hasDotTypeDotSizeDirective()) {
992 // We can get the size as difference between the function label and the
994 const MCExpr *SizeExp = MCBinaryExpr::createSub(
995 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
996 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
997 if (auto Sym = dyn_cast<MCSymbolELF>(CurrentFnSym))
998 OutStreamer->emitELFSize(Sym, SizeExp);
1001 for (const HandlerInfo &HI : Handlers) {
1002 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
1003 HI.Handler->markFunctionEnd();
1006 // Print out jump tables referenced by the function.
1007 EmitJumpTableInfo();
1009 // Emit post-function debug and/or EH information.
1010 for (const HandlerInfo &HI : Handlers) {
1011 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
1012 HI.Handler->endFunction(MF);
1016 OutStreamer->AddBlankLine();
1019 /// \brief Compute the number of Global Variables that uses a Constant.
1020 static unsigned getNumGlobalVariableUses(const Constant *C) {
1024 if (isa<GlobalVariable>(C))
1027 unsigned NumUses = 0;
1028 for (auto *CU : C->users())
1029 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1034 /// \brief Only consider global GOT equivalents if at least one user is a
1035 /// cstexpr inside an initializer of another global variables. Also, don't
1036 /// handle cstexpr inside instructions. During global variable emission,
1037 /// candidates are skipped and are emitted later in case at least one cstexpr
1038 /// isn't replaced by a PC relative GOT entry access.
1039 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1040 unsigned &NumGOTEquivUsers) {
1041 // Global GOT equivalents are unnamed private globals with a constant
1042 // pointer initializer to another global symbol. They must point to a
1043 // GlobalVariable or Function, i.e., as GlobalValue.
1044 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
1045 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
1048 // To be a got equivalent, at least one of its users need to be a constant
1049 // expression used by another global variable.
1050 for (auto *U : GV->users())
1051 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1053 return NumGOTEquivUsers > 0;
1056 /// \brief Unnamed constant global variables solely contaning a pointer to
1057 /// another globals variable is equivalent to a GOT table entry; it contains the
1058 /// the address of another symbol. Optimize it and replace accesses to these
1059 /// "GOT equivalents" by using the GOT entry for the final global instead.
1060 /// Compute GOT equivalent candidates among all global variables to avoid
1061 /// emitting them if possible later on, after it use is replaced by a GOT entry
1063 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1064 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1067 for (const auto &G : M.globals()) {
1068 unsigned NumGOTEquivUsers = 0;
1069 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1072 const MCSymbol *GOTEquivSym = getSymbol(&G);
1073 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1077 /// \brief Constant expressions using GOT equivalent globals may not be eligible
1078 /// for PC relative GOT entry conversion, in such cases we need to emit such
1079 /// globals we previously omitted in EmitGlobalVariable.
1080 void AsmPrinter::emitGlobalGOTEquivs() {
1081 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1084 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1085 for (auto &I : GlobalGOTEquivs) {
1086 const GlobalVariable *GV = I.second.first;
1087 unsigned Cnt = I.second.second;
1089 FailedCandidates.push_back(GV);
1091 GlobalGOTEquivs.clear();
1093 for (auto *GV : FailedCandidates)
1094 EmitGlobalVariable(GV);
1097 bool AsmPrinter::doFinalization(Module &M) {
1098 // Set the MachineFunction to nullptr so that we can catch attempted
1099 // accesses to MF specific features at the module level and so that
1100 // we can conditionalize accesses based on whether or not it is nullptr.
1103 // Gather all GOT equivalent globals in the module. We really need two
1104 // passes over the globals: one to compute and another to avoid its emission
1105 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1106 // where the got equivalent shows up before its use.
1107 computeGlobalGOTEquivs(M);
1109 // Emit global variables.
1110 for (const auto &G : M.globals())
1111 EmitGlobalVariable(&G);
1113 // Emit remaining GOT equivalent globals.
1114 emitGlobalGOTEquivs();
1116 // Emit visibility info for declarations
1117 for (const Function &F : M) {
1118 if (!F.isDeclarationForLinker())
1120 GlobalValue::VisibilityTypes V = F.getVisibility();
1121 if (V == GlobalValue::DefaultVisibility)
1124 MCSymbol *Name = getSymbol(&F);
1125 EmitVisibility(Name, V, false);
1128 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1130 // Emit module flags.
1131 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1132 M.getModuleFlagsMetadata(ModuleFlags);
1133 if (!ModuleFlags.empty())
1134 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, *Mang, TM);
1136 if (TM.getTargetTriple().isOSBinFormatELF()) {
1137 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1139 // Output stubs for external and common global variables.
1140 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1141 if (!Stubs.empty()) {
1142 OutStreamer->SwitchSection(TLOF.getDataRelSection());
1143 const DataLayout &DL = M.getDataLayout();
1145 for (const auto &Stub : Stubs) {
1146 OutStreamer->EmitLabel(Stub.first);
1147 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1148 DL.getPointerSize());
1153 // Finalize debug and EH information.
1154 for (const HandlerInfo &HI : Handlers) {
1155 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
1156 TimePassesIsEnabled);
1157 HI.Handler->endModule();
1163 // If the target wants to know about weak references, print them all.
1164 if (MAI->getWeakRefDirective()) {
1165 // FIXME: This is not lazy, it would be nice to only print weak references
1166 // to stuff that is actually used. Note that doing so would require targets
1167 // to notice uses in operands (due to constant exprs etc). This should
1168 // happen with the MC stuff eventually.
1170 // Print out module-level global variables here.
1171 for (const auto &G : M.globals()) {
1172 if (!G.hasExternalWeakLinkage())
1174 OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
1177 for (const auto &F : M) {
1178 if (!F.hasExternalWeakLinkage())
1180 OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1184 OutStreamer->AddBlankLine();
1185 for (const auto &Alias : M.aliases()) {
1186 MCSymbol *Name = getSymbol(&Alias);
1188 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1189 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1190 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1191 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1193 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1195 EmitVisibility(Name, Alias.getVisibility());
1197 // Emit the directives as assignments aka .set:
1198 OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1200 // If the aliasee does not correspond to a symbol in the output, i.e. the
1201 // alias is not of an object or the aliased object is private, then set the
1202 // size of the alias symbol from the type of the alias. We don't do this in
1203 // other situations as the alias and aliasee having differing types but same
1204 // size may be intentional.
1205 const GlobalObject *BaseObject = Alias.getBaseObject();
1206 if (MAI->hasDotTypeDotSizeDirective() && Alias.getValueType()->isSized() &&
1207 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1208 const DataLayout &DL = M.getDataLayout();
1209 uint64_t Size = DL.getTypeAllocSize(Alias.getValueType());
1210 OutStreamer->emitELFSize(cast<MCSymbolELF>(Name),
1211 MCConstantExpr::create(Size, OutContext));
1215 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1216 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1217 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1218 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1219 MP->finishAssembly(M, *MI, *this);
1221 // Emit llvm.ident metadata in an '.ident' directive.
1222 EmitModuleIdents(M);
1224 // Emit __morestack address if needed for indirect calls.
1225 if (MMI->usesMorestackAddr()) {
1226 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1227 getDataLayout(), SectionKind::getReadOnly(),
1229 OutStreamer->SwitchSection(ReadOnlySection);
1231 MCSymbol *AddrSymbol =
1232 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1233 OutStreamer->EmitLabel(AddrSymbol);
1235 unsigned PtrSize = M.getDataLayout().getPointerSize(0);
1236 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1240 // If we don't have any trampolines, then we don't require stack memory
1241 // to be executable. Some targets have a directive to declare this.
1242 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1243 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1244 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1245 OutStreamer->SwitchSection(S);
1247 // Allow the target to emit any magic that it wants at the end of the file,
1248 // after everything else has gone out.
1249 EmitEndOfAsmFile(M);
1251 delete Mang; Mang = nullptr;
1254 OutStreamer->Finish();
1255 OutStreamer->reset();
1260 MCSymbol *AsmPrinter::getCurExceptionSym() {
1261 if (!CurExceptionSym)
1262 CurExceptionSym = createTempSymbol("exception");
1263 return CurExceptionSym;
1266 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1268 // Get the function symbol.
1269 CurrentFnSym = getSymbol(MF.getFunction());
1270 CurrentFnSymForSize = CurrentFnSym;
1271 CurrentFnBegin = nullptr;
1272 CurExceptionSym = nullptr;
1273 bool NeedsLocalForSize = MAI->needsLocalForSize();
1274 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1275 MMI->hasEHFunclets() || NeedsLocalForSize) {
1276 CurrentFnBegin = createTempSymbol("func_begin");
1277 if (NeedsLocalForSize)
1278 CurrentFnSymForSize = CurrentFnBegin;
1282 LI = &getAnalysis<MachineLoopInfo>();
1286 // Keep track the alignment, constpool entries per Section.
1290 SmallVector<unsigned, 4> CPEs;
1291 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1295 /// EmitConstantPool - Print to the current output stream assembly
1296 /// representations of the constants in the constant pool MCP. This is
1297 /// used to print out constants which have been "spilled to memory" by
1298 /// the code generator.
1300 void AsmPrinter::EmitConstantPool() {
1301 const MachineConstantPool *MCP = MF->getConstantPool();
1302 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1303 if (CP.empty()) return;
1305 // Calculate sections for constant pool entries. We collect entries to go into
1306 // the same section together to reduce amount of section switch statements.
1307 SmallVector<SectionCPs, 4> CPSections;
1308 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1309 const MachineConstantPoolEntry &CPE = CP[i];
1310 unsigned Align = CPE.getAlignment();
1312 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1314 const Constant *C = nullptr;
1315 if (!CPE.isMachineConstantPoolEntry())
1316 C = CPE.Val.ConstVal;
1319 getObjFileLowering().getSectionForConstant(getDataLayout(), Kind, C);
1321 // The number of sections are small, just do a linear search from the
1322 // last section to the first.
1324 unsigned SecIdx = CPSections.size();
1325 while (SecIdx != 0) {
1326 if (CPSections[--SecIdx].S == S) {
1332 SecIdx = CPSections.size();
1333 CPSections.push_back(SectionCPs(S, Align));
1336 if (Align > CPSections[SecIdx].Alignment)
1337 CPSections[SecIdx].Alignment = Align;
1338 CPSections[SecIdx].CPEs.push_back(i);
1341 // Now print stuff into the calculated sections.
1342 const MCSection *CurSection = nullptr;
1343 unsigned Offset = 0;
1344 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1345 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1346 unsigned CPI = CPSections[i].CPEs[j];
1347 MCSymbol *Sym = GetCPISymbol(CPI);
1348 if (!Sym->isUndefined())
1351 if (CurSection != CPSections[i].S) {
1352 OutStreamer->SwitchSection(CPSections[i].S);
1353 EmitAlignment(Log2_32(CPSections[i].Alignment));
1354 CurSection = CPSections[i].S;
1358 MachineConstantPoolEntry CPE = CP[CPI];
1360 // Emit inter-object padding for alignment.
1361 unsigned AlignMask = CPE.getAlignment() - 1;
1362 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1363 OutStreamer->EmitZeros(NewOffset - Offset);
1365 Type *Ty = CPE.getType();
1366 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1368 OutStreamer->EmitLabel(Sym);
1369 if (CPE.isMachineConstantPoolEntry())
1370 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1372 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1377 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1378 /// by the current function to the current output stream.
1380 void AsmPrinter::EmitJumpTableInfo() {
1381 const DataLayout &DL = MF->getDataLayout();
1382 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1384 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1385 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1386 if (JT.empty()) return;
1388 // Pick the directive to use to print the jump table entries, and switch to
1389 // the appropriate section.
1390 const Function *F = MF->getFunction();
1391 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1392 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1393 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1395 if (JTInDiffSection) {
1396 // Drop it in the readonly section.
1397 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(*F, *Mang, TM);
1398 OutStreamer->SwitchSection(ReadOnlySection);
1401 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1403 // Jump tables in code sections are marked with a data_region directive
1404 // where that's supported.
1405 if (!JTInDiffSection)
1406 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1408 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1409 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1411 // If this jump table was deleted, ignore it.
1412 if (JTBBs.empty()) continue;
1414 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1415 /// emit a .set directive for each unique entry.
1416 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1417 MAI->doesSetDirectiveSuppressesReloc()) {
1418 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1419 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1420 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1421 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1422 const MachineBasicBlock *MBB = JTBBs[ii];
1423 if (!EmittedSets.insert(MBB).second)
1426 // .set LJTSet, LBB32-base
1428 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1429 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1430 MCBinaryExpr::createSub(LHS, Base,
1435 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1436 // before each jump table. The first label is never referenced, but tells
1437 // the assembler and linker the extents of the jump table object. The
1438 // second label is actually referenced by the code.
1439 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1440 // FIXME: This doesn't have to have any specific name, just any randomly
1441 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1442 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1444 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1446 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1447 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1449 if (!JTInDiffSection)
1450 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1453 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1455 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1456 const MachineBasicBlock *MBB,
1457 unsigned UID) const {
1458 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1459 const MCExpr *Value = nullptr;
1460 switch (MJTI->getEntryKind()) {
1461 case MachineJumpTableInfo::EK_Inline:
1462 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1463 case MachineJumpTableInfo::EK_Custom32:
1464 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1465 MJTI, MBB, UID, OutContext);
1467 case MachineJumpTableInfo::EK_BlockAddress:
1468 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1470 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1472 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1473 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1474 // with a relocation as gp-relative, e.g.:
1476 MCSymbol *MBBSym = MBB->getSymbol();
1477 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1481 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1482 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1483 // with a relocation as gp-relative, e.g.:
1485 MCSymbol *MBBSym = MBB->getSymbol();
1486 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1490 case MachineJumpTableInfo::EK_LabelDifference32: {
1491 // Each entry is the address of the block minus the address of the jump
1492 // table. This is used for PIC jump tables where gprel32 is not supported.
1494 // .word LBB123 - LJTI1_2
1495 // If the .set directive avoids relocations, this is emitted as:
1496 // .set L4_5_set_123, LBB123 - LJTI1_2
1497 // .word L4_5_set_123
1498 if (MAI->doesSetDirectiveSuppressesReloc()) {
1499 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1503 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1504 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1505 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1506 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1511 assert(Value && "Unknown entry kind!");
1513 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1514 OutStreamer->EmitValue(Value, EntrySize);
1518 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1519 /// special global used by LLVM. If so, emit it and return true, otherwise
1520 /// do nothing and return false.
1521 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1522 if (GV->getName() == "llvm.used") {
1523 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1524 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1528 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1529 if (StringRef(GV->getSection()) == "llvm.metadata" ||
1530 GV->hasAvailableExternallyLinkage())
1533 if (!GV->hasAppendingLinkage()) return false;
1535 assert(GV->hasInitializer() && "Not a special LLVM global!");
1537 if (GV->getName() == "llvm.global_ctors") {
1538 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1541 if (TM.getRelocationModel() == Reloc::Static &&
1542 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1543 StringRef Sym(".constructors_used");
1544 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1550 if (GV->getName() == "llvm.global_dtors") {
1551 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1552 /* isCtor */ false);
1554 if (TM.getRelocationModel() == Reloc::Static &&
1555 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1556 StringRef Sym(".destructors_used");
1557 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1566 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1567 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1568 /// is true, as being used with this directive.
1569 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1570 // Should be an array of 'i8*'.
1571 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1572 const GlobalValue *GV =
1573 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1575 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1581 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
1583 llvm::Constant *Func;
1584 llvm::GlobalValue *ComdatKey;
1588 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1590 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1592 // Should be an array of '{ int, void ()* }' structs. The first value is the
1594 if (!isa<ConstantArray>(List)) return;
1596 // Sanity check the structors list.
1597 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1598 if (!InitList) return; // Not an array!
1599 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1600 // FIXME: Only allow the 3-field form in LLVM 4.0.
1601 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1602 return; // Not an array of two or three elements!
1603 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1604 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1605 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1606 return; // Not (int, ptr, ptr).
1608 // Gather the structors in a form that's convenient for sorting by priority.
1609 SmallVector<Structor, 8> Structors;
1610 for (Value *O : InitList->operands()) {
1611 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1612 if (!CS) continue; // Malformed.
1613 if (CS->getOperand(1)->isNullValue())
1614 break; // Found a null terminator, skip the rest.
1615 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1616 if (!Priority) continue; // Malformed.
1617 Structors.push_back(Structor());
1618 Structor &S = Structors.back();
1619 S.Priority = Priority->getLimitedValue(65535);
1620 S.Func = CS->getOperand(1);
1621 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1622 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1625 // Emit the function pointers in the target-specific order
1626 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1627 std::stable_sort(Structors.begin(), Structors.end(),
1628 [](const Structor &L,
1629 const Structor &R) { return L.Priority < R.Priority; });
1630 for (Structor &S : Structors) {
1631 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1632 const MCSymbol *KeySym = nullptr;
1633 if (GlobalValue *GV = S.ComdatKey) {
1634 if (GV->hasAvailableExternallyLinkage())
1635 // If the associated variable is available_externally, some other TU
1636 // will provide its dynamic initializer.
1639 KeySym = getSymbol(GV);
1641 MCSection *OutputSection =
1642 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1643 : Obj.getStaticDtorSection(S.Priority, KeySym));
1644 OutStreamer->SwitchSection(OutputSection);
1645 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1646 EmitAlignment(Align);
1647 EmitXXStructor(DL, S.Func);
1651 void AsmPrinter::EmitModuleIdents(Module &M) {
1652 if (!MAI->hasIdentDirective())
1655 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1656 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1657 const MDNode *N = NMD->getOperand(i);
1658 assert(N->getNumOperands() == 1 &&
1659 "llvm.ident metadata entry can have only one operand");
1660 const MDString *S = cast<MDString>(N->getOperand(0));
1661 OutStreamer->EmitIdent(S->getString());
1666 //===--------------------------------------------------------------------===//
1667 // Emission and print routines
1670 /// EmitInt8 - Emit a byte directive and value.
1672 void AsmPrinter::EmitInt8(int Value) const {
1673 OutStreamer->EmitIntValue(Value, 1);
1676 /// EmitInt16 - Emit a short directive and value.
1678 void AsmPrinter::EmitInt16(int Value) const {
1679 OutStreamer->EmitIntValue(Value, 2);
1682 /// EmitInt32 - Emit a long directive and value.
1684 void AsmPrinter::EmitInt32(int Value) const {
1685 OutStreamer->EmitIntValue(Value, 4);
1688 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1689 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1690 /// .set if it avoids relocations.
1691 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1692 unsigned Size) const {
1693 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
1696 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1697 /// where the size in bytes of the directive is specified by Size and Label
1698 /// specifies the label. This implicitly uses .set if it is available.
1699 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1701 bool IsSectionRelative) const {
1702 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1703 OutStreamer->EmitCOFFSecRel32(Label);
1707 // Emit Label+Offset (or just Label if Offset is zero)
1708 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
1710 Expr = MCBinaryExpr::createAdd(
1711 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
1713 OutStreamer->EmitValue(Expr, Size);
1716 //===----------------------------------------------------------------------===//
1718 // EmitAlignment - Emit an alignment directive to the specified power of
1719 // two boundary. For example, if you pass in 3 here, you will get an 8
1720 // byte alignment. If a global value is specified, and if that global has
1721 // an explicit alignment requested, it will override the alignment request
1722 // if required for correctness.
1724 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1726 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
1728 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1731 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1732 "undefined behavior");
1733 if (getCurrentSection()->getKind().isText())
1734 OutStreamer->EmitCodeAlignment(1u << NumBits);
1736 OutStreamer->EmitValueToAlignment(1u << NumBits);
1739 //===----------------------------------------------------------------------===//
1740 // Constant emission.
1741 //===----------------------------------------------------------------------===//
1743 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1744 MCContext &Ctx = OutContext;
1746 if (CV->isNullValue() || isa<UndefValue>(CV))
1747 return MCConstantExpr::create(0, Ctx);
1749 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1750 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
1752 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1753 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
1755 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1756 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
1758 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1760 llvm_unreachable("Unknown constant value to lower!");
1763 if (const MCExpr *RelocExpr
1764 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1767 switch (CE->getOpcode()) {
1769 // If the code isn't optimized, there may be outstanding folding
1770 // opportunities. Attempt to fold the expression using DataLayout as a
1771 // last resort before giving up.
1772 if (Constant *C = ConstantFoldConstantExpression(CE, getDataLayout()))
1774 return lowerConstant(C);
1776 // Otherwise report the problem to the user.
1779 raw_string_ostream OS(S);
1780 OS << "Unsupported expression in static initializer: ";
1781 CE->printAsOperand(OS, /*PrintType=*/false,
1782 !MF ? nullptr : MF->getFunction()->getParent());
1783 report_fatal_error(OS.str());
1785 case Instruction::GetElementPtr: {
1786 // Generate a symbolic expression for the byte address
1787 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
1788 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
1790 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1794 int64_t Offset = OffsetAI.getSExtValue();
1795 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
1799 case Instruction::Trunc:
1800 // We emit the value and depend on the assembler to truncate the generated
1801 // expression properly. This is important for differences between
1802 // blockaddress labels. Since the two labels are in the same function, it
1803 // is reasonable to treat their delta as a 32-bit value.
1805 case Instruction::BitCast:
1806 return lowerConstant(CE->getOperand(0));
1808 case Instruction::IntToPtr: {
1809 const DataLayout &DL = getDataLayout();
1811 // Handle casts to pointers by changing them into casts to the appropriate
1812 // integer type. This promotes constant folding and simplifies this code.
1813 Constant *Op = CE->getOperand(0);
1814 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1816 return lowerConstant(Op);
1819 case Instruction::PtrToInt: {
1820 const DataLayout &DL = getDataLayout();
1822 // Support only foldable casts to/from pointers that can be eliminated by
1823 // changing the pointer to the appropriately sized integer type.
1824 Constant *Op = CE->getOperand(0);
1825 Type *Ty = CE->getType();
1827 const MCExpr *OpExpr = lowerConstant(Op);
1829 // We can emit the pointer value into this slot if the slot is an
1830 // integer slot equal to the size of the pointer.
1831 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1834 // Otherwise the pointer is smaller than the resultant integer, mask off
1835 // the high bits so we are sure to get a proper truncation if the input is
1837 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1838 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
1839 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
1842 // The MC library also has a right-shift operator, but it isn't consistently
1843 // signed or unsigned between different targets.
1844 case Instruction::Add:
1845 case Instruction::Sub:
1846 case Instruction::Mul:
1847 case Instruction::SDiv:
1848 case Instruction::SRem:
1849 case Instruction::Shl:
1850 case Instruction::And:
1851 case Instruction::Or:
1852 case Instruction::Xor: {
1853 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1854 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1855 switch (CE->getOpcode()) {
1856 default: llvm_unreachable("Unknown binary operator constant cast expr");
1857 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
1858 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
1859 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
1860 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
1861 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
1862 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
1863 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
1864 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
1865 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
1871 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
1873 const Constant *BaseCV = nullptr,
1874 uint64_t Offset = 0);
1876 /// isRepeatedByteSequence - Determine whether the given value is
1877 /// composed of a repeated sequence of identical bytes and return the
1878 /// byte value. If it is not a repeated sequence, return -1.
1879 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1880 StringRef Data = V->getRawDataValues();
1881 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1883 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1884 if (Data[i] != C) return -1;
1885 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1889 /// isRepeatedByteSequence - Determine whether the given value is
1890 /// composed of a repeated sequence of identical bytes and return the
1891 /// byte value. If it is not a repeated sequence, return -1.
1892 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
1893 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1894 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
1895 assert(Size % 8 == 0);
1897 // Extend the element to take zero padding into account.
1898 APInt Value = CI->getValue().zextOrSelf(Size);
1899 if (!Value.isSplat(8))
1902 return Value.zextOrTrunc(8).getZExtValue();
1904 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1905 // Make sure all array elements are sequences of the same repeated
1907 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1908 Constant *Op0 = CA->getOperand(0);
1909 int Byte = isRepeatedByteSequence(Op0, DL);
1913 // All array elements must be equal.
1914 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
1915 if (CA->getOperand(i) != Op0)
1920 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1921 return isRepeatedByteSequence(CDS);
1926 static void emitGlobalConstantDataSequential(const DataLayout &DL,
1927 const ConstantDataSequential *CDS,
1930 // See if we can aggregate this into a .fill, if so, emit it as such.
1931 int Value = isRepeatedByteSequence(CDS, DL);
1933 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
1934 // Don't emit a 1-byte object as a .fill.
1936 return AP.OutStreamer->EmitFill(Bytes, Value);
1939 // If this can be emitted with .ascii/.asciz, emit it as such.
1940 if (CDS->isString())
1941 return AP.OutStreamer->EmitBytes(CDS->getAsString());
1943 // Otherwise, emit the values in successive locations.
1944 unsigned ElementByteSize = CDS->getElementByteSize();
1945 if (isa<IntegerType>(CDS->getElementType())) {
1946 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1948 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
1949 CDS->getElementAsInteger(i));
1950 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
1953 } else if (ElementByteSize == 4) {
1954 // FP Constants are printed as integer constants to avoid losing
1956 assert(CDS->getElementType()->isFloatTy());
1957 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1963 F = CDS->getElementAsFloat(i);
1965 AP.OutStreamer->GetCommentOS() << "float " << F << '\n';
1966 AP.OutStreamer->EmitIntValue(I, 4);
1969 assert(CDS->getElementType()->isDoubleTy());
1970 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1976 F = CDS->getElementAsDouble(i);
1978 AP.OutStreamer->GetCommentOS() << "double " << F << '\n';
1979 AP.OutStreamer->EmitIntValue(I, 8);
1983 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1984 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1985 CDS->getNumElements();
1986 if (unsigned Padding = Size - EmittedSize)
1987 AP.OutStreamer->EmitZeros(Padding);
1991 static void emitGlobalConstantArray(const DataLayout &DL,
1992 const ConstantArray *CA, AsmPrinter &AP,
1993 const Constant *BaseCV, uint64_t Offset) {
1994 // See if we can aggregate some values. Make sure it can be
1995 // represented as a series of bytes of the constant value.
1996 int Value = isRepeatedByteSequence(CA, DL);
1999 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2000 AP.OutStreamer->EmitFill(Bytes, Value);
2003 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2004 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2005 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2010 static void emitGlobalConstantVector(const DataLayout &DL,
2011 const ConstantVector *CV, AsmPrinter &AP) {
2012 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2013 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2015 unsigned Size = DL.getTypeAllocSize(CV->getType());
2016 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2017 CV->getType()->getNumElements();
2018 if (unsigned Padding = Size - EmittedSize)
2019 AP.OutStreamer->EmitZeros(Padding);
2022 static void emitGlobalConstantStruct(const DataLayout &DL,
2023 const ConstantStruct *CS, AsmPrinter &AP,
2024 const Constant *BaseCV, uint64_t Offset) {
2025 // Print the fields in successive locations. Pad to align if needed!
2026 unsigned Size = DL.getTypeAllocSize(CS->getType());
2027 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2028 uint64_t SizeSoFar = 0;
2029 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2030 const Constant *Field = CS->getOperand(i);
2032 // Print the actual field value.
2033 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2035 // Check if padding is needed and insert one or more 0s.
2036 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2037 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2038 - Layout->getElementOffset(i)) - FieldSize;
2039 SizeSoFar += FieldSize + PadSize;
2041 // Insert padding - this may include padding to increase the size of the
2042 // current field up to the ABI size (if the struct is not packed) as well
2043 // as padding to ensure that the next field starts at the right offset.
2044 AP.OutStreamer->EmitZeros(PadSize);
2046 assert(SizeSoFar == Layout->getSizeInBytes() &&
2047 "Layout of constant struct may be incorrect!");
2050 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2051 APInt API = CFP->getValueAPF().bitcastToAPInt();
2053 // First print a comment with what we think the original floating-point value
2054 // should have been.
2055 if (AP.isVerbose()) {
2056 SmallString<8> StrVal;
2057 CFP->getValueAPF().toString(StrVal);
2060 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
2062 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2063 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2066 // Now iterate through the APInt chunks, emitting them in endian-correct
2067 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2069 unsigned NumBytes = API.getBitWidth() / 8;
2070 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2071 const uint64_t *p = API.getRawData();
2073 // PPC's long double has odd notions of endianness compared to how LLVM
2074 // handles it: p[0] goes first for *big* endian on PPC.
2075 if (AP.getDataLayout().isBigEndian() && !CFP->getType()->isPPC_FP128Ty()) {
2076 int Chunk = API.getNumWords() - 1;
2079 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2081 for (; Chunk >= 0; --Chunk)
2082 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2085 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2086 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2089 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2092 // Emit the tail padding for the long double.
2093 const DataLayout &DL = AP.getDataLayout();
2094 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2095 DL.getTypeStoreSize(CFP->getType()));
2098 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2099 const DataLayout &DL = AP.getDataLayout();
2100 unsigned BitWidth = CI->getBitWidth();
2102 // Copy the value as we may massage the layout for constants whose bit width
2103 // is not a multiple of 64-bits.
2104 APInt Realigned(CI->getValue());
2105 uint64_t ExtraBits = 0;
2106 unsigned ExtraBitsSize = BitWidth & 63;
2108 if (ExtraBitsSize) {
2109 // The bit width of the data is not a multiple of 64-bits.
2110 // The extra bits are expected to be at the end of the chunk of the memory.
2112 // * Nothing to be done, just record the extra bits to emit.
2114 // * Record the extra bits to emit.
2115 // * Realign the raw data to emit the chunks of 64-bits.
2116 if (DL.isBigEndian()) {
2117 // Basically the structure of the raw data is a chunk of 64-bits cells:
2118 // 0 1 BitWidth / 64
2119 // [chunk1][chunk2] ... [chunkN].
2120 // The most significant chunk is chunkN and it should be emitted first.
2121 // However, due to the alignment issue chunkN contains useless bits.
2122 // Realign the chunks so that they contain only useless information:
2123 // ExtraBits 0 1 (BitWidth / 64) - 1
2124 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2125 ExtraBits = Realigned.getRawData()[0] &
2126 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2127 Realigned = Realigned.lshr(ExtraBitsSize);
2129 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2132 // We don't expect assemblers to support integer data directives
2133 // for more than 64 bits, so we emit the data in at most 64-bit
2134 // quantities at a time.
2135 const uint64_t *RawData = Realigned.getRawData();
2136 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2137 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2138 AP.OutStreamer->EmitIntValue(Val, 8);
2141 if (ExtraBitsSize) {
2142 // Emit the extra bits after the 64-bits chunks.
2144 // Emit a directive that fills the expected size.
2145 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2146 Size -= (BitWidth / 64) * 8;
2147 assert(Size && Size * 8 >= ExtraBitsSize &&
2148 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2149 == ExtraBits && "Directive too small for extra bits.");
2150 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2154 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2155 /// equivalent global, by a target specific GOT pc relative access to the
2157 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2158 const Constant *BaseCst,
2160 // The global @foo below illustrates a global that uses a got equivalent.
2162 // @bar = global i32 42
2163 // @gotequiv = private unnamed_addr constant i32* @bar
2164 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2165 // i64 ptrtoint (i32* @foo to i64))
2168 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2169 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2172 // foo = cstexpr, where
2173 // cstexpr := <gotequiv> - "." + <cst>
2174 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2176 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2178 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2179 // gotpcrelcst := <offset from @foo base> + <cst>
2182 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2184 const MCSymbolRefExpr *SymA = MV.getSymA();
2188 // Check that GOT equivalent symbol is cached.
2189 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2190 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2193 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2197 // Check for a valid base symbol
2198 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2199 const MCSymbolRefExpr *SymB = MV.getSymB();
2201 if (!SymB || BaseSym != &SymB->getSymbol())
2204 // Make sure to match:
2206 // gotpcrelcst := <offset from @foo base> + <cst>
2208 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2209 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2210 // if the target knows how to encode it.
2212 int64_t GOTPCRelCst = Offset + MV.getConstant();
2213 if (GOTPCRelCst < 0)
2215 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2218 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2225 // .long gotequiv - "." + <cst>
2227 // is replaced by the target specific equivalent to:
2232 // .long bar@GOTPCREL+<gotpcrelcst>
2234 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2235 const GlobalVariable *GV = Result.first;
2236 int NumUses = (int)Result.second;
2237 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2238 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2239 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2240 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2242 // Update GOT equivalent usage information
2245 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2248 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2249 AsmPrinter &AP, const Constant *BaseCV,
2251 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2253 // Globals with sub-elements such as combinations of arrays and structs
2254 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2255 // constant symbol base and the current position with BaseCV and Offset.
2256 if (!BaseCV && CV->hasOneUse())
2257 BaseCV = dyn_cast<Constant>(CV->user_back());
2259 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2260 return AP.OutStreamer->EmitZeros(Size);
2262 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2269 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2270 CI->getZExtValue());
2271 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2274 emitGlobalConstantLargeInt(CI, AP);
2279 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2280 return emitGlobalConstantFP(CFP, AP);
2282 if (isa<ConstantPointerNull>(CV)) {
2283 AP.OutStreamer->EmitIntValue(0, Size);
2287 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2288 return emitGlobalConstantDataSequential(DL, CDS, AP);
2290 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2291 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2293 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2294 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2296 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2297 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2299 if (CE->getOpcode() == Instruction::BitCast)
2300 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2303 // If the constant expression's size is greater than 64-bits, then we have
2304 // to emit the value in chunks. Try to constant fold the value and emit it
2306 Constant *New = ConstantFoldConstantExpression(CE, DL);
2307 if (New && New != CE)
2308 return emitGlobalConstantImpl(DL, New, AP);
2312 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2313 return emitGlobalConstantVector(DL, V, AP);
2315 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2316 // thread the streamer with EmitValue.
2317 const MCExpr *ME = AP.lowerConstant(CV);
2319 // Since lowerConstant already folded and got rid of all IR pointer and
2320 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2322 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2323 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2325 AP.OutStreamer->EmitValue(ME, Size);
2328 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2329 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2330 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2332 emitGlobalConstantImpl(DL, CV, *this);
2333 else if (MAI->hasSubsectionsViaSymbols()) {
2334 // If the global has zero size, emit a single byte so that two labels don't
2335 // look like they are at the same location.
2336 OutStreamer->EmitIntValue(0, 1);
2340 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2341 // Target doesn't support this yet!
2342 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2345 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2347 OS << '+' << Offset;
2348 else if (Offset < 0)
2352 //===----------------------------------------------------------------------===//
2353 // Symbol Lowering Routines.
2354 //===----------------------------------------------------------------------===//
2356 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2357 return OutContext.createTempSymbol(Name, true);
2360 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2361 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2364 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2365 return MMI->getAddrLabelSymbol(BB);
2368 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2369 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2370 const DataLayout &DL = getDataLayout();
2371 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2372 "CPI" + Twine(getFunctionNumber()) + "_" +
2376 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2377 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2378 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2381 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2382 /// FIXME: privatize to AsmPrinter.
2383 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2384 const DataLayout &DL = getDataLayout();
2385 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2386 Twine(getFunctionNumber()) + "_" +
2387 Twine(UID) + "_set_" + Twine(MBBID));
2390 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2391 StringRef Suffix) const {
2392 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2396 /// Return the MCSymbol for the specified ExternalSymbol.
2397 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2398 SmallString<60> NameStr;
2399 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2400 return OutContext.getOrCreateSymbol(NameStr);
2405 /// PrintParentLoopComment - Print comments about parent loops of this one.
2406 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2407 unsigned FunctionNumber) {
2409 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2410 OS.indent(Loop->getLoopDepth()*2)
2411 << "Parent Loop BB" << FunctionNumber << "_"
2412 << Loop->getHeader()->getNumber()
2413 << " Depth=" << Loop->getLoopDepth() << '\n';
2417 /// PrintChildLoopComment - Print comments about child loops within
2418 /// the loop for this basic block, with nesting.
2419 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2420 unsigned FunctionNumber) {
2421 // Add child loop information
2422 for (const MachineLoop *CL : *Loop) {
2423 OS.indent(CL->getLoopDepth()*2)
2424 << "Child Loop BB" << FunctionNumber << "_"
2425 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2427 PrintChildLoopComment(OS, CL, FunctionNumber);
2431 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2432 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2433 const MachineLoopInfo *LI,
2434 const AsmPrinter &AP) {
2435 // Add loop depth information
2436 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2439 MachineBasicBlock *Header = Loop->getHeader();
2440 assert(Header && "No header for loop");
2442 // If this block is not a loop header, just print out what is the loop header
2444 if (Header != &MBB) {
2445 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2446 Twine(AP.getFunctionNumber())+"_" +
2447 Twine(Loop->getHeader()->getNumber())+
2448 " Depth="+Twine(Loop->getLoopDepth()));
2452 // Otherwise, it is a loop header. Print out information about child and
2454 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2456 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2459 OS.indent(Loop->getLoopDepth()*2-2);
2464 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2466 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2470 /// EmitBasicBlockStart - This method prints the label for the specified
2471 /// MachineBasicBlock, an alignment (if present) and a comment describing
2472 /// it if appropriate.
2473 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2474 // End the previous funclet and start a new one.
2475 if (MBB.isEHFuncletEntry()) {
2476 for (const HandlerInfo &HI : Handlers) {
2477 HI.Handler->endFunclet();
2478 HI.Handler->beginFunclet(MBB);
2482 // Emit an alignment directive for this block, if needed.
2483 if (unsigned Align = MBB.getAlignment())
2484 EmitAlignment(Align);
2486 // If the block has its address taken, emit any labels that were used to
2487 // reference the block. It is possible that there is more than one label
2488 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2489 // the references were generated.
2490 if (MBB.hasAddressTaken()) {
2491 const BasicBlock *BB = MBB.getBasicBlock();
2493 OutStreamer->AddComment("Block address taken");
2495 // MBBs can have their address taken as part of CodeGen without having
2496 // their corresponding BB's address taken in IR
2497 if (BB->hasAddressTaken())
2498 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2499 OutStreamer->EmitLabel(Sym);
2502 // Print some verbose block comments.
2504 if (const BasicBlock *BB = MBB.getBasicBlock())
2506 OutStreamer->AddComment("%" + BB->getName());
2507 emitBasicBlockLoopComments(MBB, LI, *this);
2510 // Print the main label for the block.
2511 if (MBB.pred_empty() ||
2512 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2514 // NOTE: Want this comment at start of line, don't emit with AddComment.
2515 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2518 OutStreamer->EmitLabel(MBB.getSymbol());
2522 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2523 bool IsDefinition) const {
2524 MCSymbolAttr Attr = MCSA_Invalid;
2526 switch (Visibility) {
2528 case GlobalValue::HiddenVisibility:
2530 Attr = MAI->getHiddenVisibilityAttr();
2532 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2534 case GlobalValue::ProtectedVisibility:
2535 Attr = MAI->getProtectedVisibilityAttr();
2539 if (Attr != MCSA_Invalid)
2540 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2543 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2544 /// exactly one predecessor and the control transfer mechanism between
2545 /// the predecessor and this block is a fall-through.
2547 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2548 // If this is a landing pad, it isn't a fall through. If it has no preds,
2549 // then nothing falls through to it.
2550 if (MBB->isEHPad() || MBB->pred_empty())
2553 // If there isn't exactly one predecessor, it can't be a fall through.
2554 if (MBB->pred_size() > 1)
2557 // The predecessor has to be immediately before this block.
2558 MachineBasicBlock *Pred = *MBB->pred_begin();
2559 if (!Pred->isLayoutSuccessor(MBB))
2562 // If the block is completely empty, then it definitely does fall through.
2566 // Check the terminators in the previous blocks
2567 for (const auto &MI : Pred->terminators()) {
2568 // If it is not a simple branch, we are in a table somewhere.
2569 if (!MI.isBranch() || MI.isIndirectBranch())
2572 // If we are the operands of one of the branches, this is not a fall
2573 // through. Note that targets with delay slots will usually bundle
2574 // terminators with the delay slot instruction.
2575 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2578 if (OP->isMBB() && OP->getMBB() == MBB)
2588 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2589 if (!S.usesMetadata())
2592 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2593 " stackmap formats, please see the documentation for a description of"
2594 " the default format. If you really need a custom serialized format,"
2595 " please file a bug");
2597 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2598 gcp_map_type::iterator GCPI = GCMap.find(&S);
2599 if (GCPI != GCMap.end())
2600 return GCPI->second.get();
2602 const char *Name = S.getName().c_str();
2604 for (GCMetadataPrinterRegistry::iterator
2605 I = GCMetadataPrinterRegistry::begin(),
2606 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2607 if (strcmp(Name, I->getName()) == 0) {
2608 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2610 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2611 return IterBool.first->second.get();
2614 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2617 /// Pin vtable to this file.
2618 AsmPrinterHandler::~AsmPrinterHandler() {}
2620 void AsmPrinterHandler::markFunctionEnd() {}