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 "Win64Exception.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/Analysis/JumpInstrTableInfo.h"
23 #include "llvm/CodeGen/Analysis.h"
24 #include "llvm/CodeGen/GCMetadataPrinter.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineFrameInfo.h"
27 #include "llvm/CodeGen/MachineFunction.h"
28 #include "llvm/CodeGen/MachineInstrBundle.h"
29 #include "llvm/CodeGen/MachineJumpTableInfo.h"
30 #include "llvm/CodeGen/MachineLoopInfo.h"
31 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/DebugInfo.h"
34 #include "llvm/IR/Mangler.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/IR/Operator.h"
37 #include "llvm/MC/MCAsmInfo.h"
38 #include "llvm/MC/MCContext.h"
39 #include "llvm/MC/MCExpr.h"
40 #include "llvm/MC/MCInst.h"
41 #include "llvm/MC/MCSection.h"
42 #include "llvm/MC/MCStreamer.h"
43 #include "llvm/MC/MCSymbol.h"
44 #include "llvm/MC/MCValue.h"
45 #include "llvm/Support/ErrorHandling.h"
46 #include "llvm/Support/Format.h"
47 #include "llvm/Support/MathExtras.h"
48 #include "llvm/Support/TargetRegistry.h"
49 #include "llvm/Support/Timer.h"
50 #include "llvm/Target/TargetFrameLowering.h"
51 #include "llvm/Target/TargetInstrInfo.h"
52 #include "llvm/Target/TargetLowering.h"
53 #include "llvm/Target/TargetLoweringObjectFile.h"
54 #include "llvm/Target/TargetRegisterInfo.h"
55 #include "llvm/Target/TargetSubtargetInfo.h"
58 #define DEBUG_TYPE "asm-printer"
60 static const char *const DWARFGroupName = "DWARF Emission";
61 static const char *const DbgTimerName = "Debug Info Emission";
62 static const char *const EHTimerName = "DWARF Exception Writer";
63 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
65 STATISTIC(EmittedInsts, "Number of machine instrs printed");
67 char AsmPrinter::ID = 0;
69 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
70 static gcp_map_type &getGCMap(void *&P) {
72 P = new gcp_map_type();
73 return *(gcp_map_type*)P;
77 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
78 /// value in log2 form. This rounds up to the preferred alignment if possible
80 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
81 unsigned InBits = 0) {
83 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
84 NumBits = DL.getPreferredAlignmentLog(GVar);
86 // If InBits is specified, round it to it.
90 // If the GV has a specified alignment, take it into account.
91 if (GV->getAlignment() == 0)
94 unsigned GVAlign = Log2_32(GV->getAlignment());
96 // If the GVAlign is larger than NumBits, or if we are required to obey
97 // NumBits because the GV has an assigned section, obey it.
98 if (GVAlign > NumBits || GV->hasSection())
103 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
104 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
105 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)),
106 LastMI(nullptr), LastFn(0), Counter(~0U) {
111 CurExceptionSym = CurrentFnSym = CurrentFnSymForSize = nullptr;
112 CurrentFnBegin = nullptr;
113 CurrentFnEnd = nullptr;
114 GCMetadataPrinters = nullptr;
115 VerboseAsm = OutStreamer->isVerboseAsm();
118 AsmPrinter::~AsmPrinter() {
119 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
121 if (GCMetadataPrinters) {
122 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
125 GCMetadataPrinters = nullptr;
129 /// getFunctionNumber - Return a unique ID for the current function.
131 unsigned AsmPrinter::getFunctionNumber() const {
132 return MF->getFunctionNumber();
135 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
136 return *TM.getObjFileLowering();
139 /// getDataLayout - Return information about data layout.
140 const DataLayout &AsmPrinter::getDataLayout() const {
141 return *TM.getDataLayout();
144 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
145 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
146 return MF->getSubtarget<MCSubtargetInfo>();
149 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
150 S.EmitInstruction(Inst, getSubtargetInfo());
153 StringRef AsmPrinter::getTargetTriple() const {
154 return TM.getTargetTriple();
157 /// getCurrentSection() - Return the current section we are emitting to.
158 const MCSection *AsmPrinter::getCurrentSection() const {
159 return OutStreamer->getCurrentSection().first;
164 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
165 AU.setPreservesAll();
166 MachineFunctionPass::getAnalysisUsage(AU);
167 AU.addRequired<MachineModuleInfo>();
168 AU.addRequired<GCModuleInfo>();
170 AU.addRequired<MachineLoopInfo>();
173 bool AsmPrinter::doInitialization(Module &M) {
174 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
175 MMI->AnalyzeModule(M);
177 // Initialize TargetLoweringObjectFile.
178 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
179 .Initialize(OutContext, TM);
181 OutStreamer->InitSections(false);
183 Mang = new Mangler(TM.getDataLayout());
185 // Emit the version-min deplyment target directive if needed.
187 // FIXME: If we end up with a collection of these sorts of Darwin-specific
188 // or ELF-specific things, it may make sense to have a platform helper class
189 // that will work with the target helper class. For now keep it here, as the
190 // alternative is duplicated code in each of the target asm printers that
191 // use the directive, where it would need the same conditionalization
193 Triple TT(getTargetTriple());
194 if (TT.isOSDarwin()) {
195 unsigned Major, Minor, Update;
196 TT.getOSVersion(Major, Minor, Update);
197 // If there is a version specified, Major will be non-zero.
199 OutStreamer->EmitVersionMin((TT.isMacOSX() ?
200 MCVM_OSXVersionMin : MCVM_IOSVersionMin),
201 Major, Minor, Update);
204 // Allow the target to emit any magic that it wants at the start of the file.
205 EmitStartOfAsmFile(M);
207 // Very minimal debug info. It is ignored if we emit actual debug info. If we
208 // don't, this at least helps the user find where a global came from.
209 if (MAI->hasSingleParameterDotFile()) {
211 OutStreamer->EmitFileDirective(M.getModuleIdentifier());
214 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
215 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
217 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
218 MP->beginAssembly(M, *MI, *this);
220 // Emit module-level inline asm if it exists.
221 if (!M.getModuleInlineAsm().empty()) {
222 // We're at the module level. Construct MCSubtarget from the default CPU
223 // and target triple.
224 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
225 TM.getTargetTriple(), TM.getTargetCPU(), TM.getTargetFeatureString()));
226 OutStreamer->AddComment("Start of file scope inline assembly");
227 OutStreamer->AddBlankLine();
228 EmitInlineAsm(M.getModuleInlineAsm()+"\n", *STI);
229 OutStreamer->AddComment("End of file scope inline assembly");
230 OutStreamer->AddBlankLine();
233 if (MAI->doesSupportDebugInformation()) {
234 bool skip_dwarf = false;
235 if (Triple(TM.getTargetTriple()).isKnownWindowsMSVCEnvironment()) {
236 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
238 CodeViewLineTablesGroupName));
239 // FIXME: Don't emit DWARF debug info if there's at least one function
240 // with AddressSanitizer instrumentation.
241 // This is a band-aid fix for PR22032.
242 for (auto &F : M.functions()) {
243 if (F.hasFnAttribute(Attribute::SanitizeAddress)) {
250 DD = new DwarfDebug(this, &M);
251 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
255 EHStreamer *ES = nullptr;
256 switch (MAI->getExceptionHandlingType()) {
257 case ExceptionHandling::None:
259 case ExceptionHandling::SjLj:
260 case ExceptionHandling::DwarfCFI:
261 ES = new DwarfCFIException(this);
263 case ExceptionHandling::ARM:
264 ES = new ARMException(this);
266 case ExceptionHandling::WinEH:
267 switch (MAI->getWinEHEncodingType()) {
268 default: llvm_unreachable("unsupported unwinding information encoding");
269 case WinEH::EncodingType::Itanium:
270 ES = new Win64Exception(this);
276 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
280 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
281 if (!MAI.hasWeakDefCanBeHiddenDirective())
284 return canBeOmittedFromSymbolTable(GV);
287 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
288 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
290 case GlobalValue::CommonLinkage:
291 case GlobalValue::LinkOnceAnyLinkage:
292 case GlobalValue::LinkOnceODRLinkage:
293 case GlobalValue::WeakAnyLinkage:
294 case GlobalValue::WeakODRLinkage:
295 if (MAI->hasWeakDefDirective()) {
297 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
299 if (!canBeHidden(GV, *MAI))
300 // .weak_definition _foo
301 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
303 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
304 } else if (MAI->hasLinkOnceDirective()) {
306 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
307 //NOTE: linkonce is handled by the section the symbol was assigned to.
310 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
313 case GlobalValue::AppendingLinkage:
314 // FIXME: appending linkage variables should go into a section of
315 // their name or something. For now, just emit them as external.
316 case GlobalValue::ExternalLinkage:
317 // If external or appending, declare as a global symbol.
319 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
321 case GlobalValue::PrivateLinkage:
322 case GlobalValue::InternalLinkage:
324 case GlobalValue::AvailableExternallyLinkage:
325 llvm_unreachable("Should never emit this");
326 case GlobalValue::ExternalWeakLinkage:
327 llvm_unreachable("Don't know how to emit these");
329 llvm_unreachable("Unknown linkage type!");
332 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
333 const GlobalValue *GV) const {
334 TM.getNameWithPrefix(Name, GV, *Mang);
337 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
338 return TM.getSymbol(GV, *Mang);
341 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
342 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
343 if (GV->hasInitializer()) {
344 // Check to see if this is a special global used by LLVM, if so, emit it.
345 if (EmitSpecialLLVMGlobal(GV))
348 // Skip the emission of global equivalents. The symbol can be emitted later
349 // on by emitGlobalGOTEquivs in case it turns out to be needed.
350 if (GlobalGOTEquivs.count(getSymbol(GV)))
354 GV->printAsOperand(OutStreamer->GetCommentOS(),
355 /*PrintType=*/false, GV->getParent());
356 OutStreamer->GetCommentOS() << '\n';
360 MCSymbol *GVSym = getSymbol(GV);
361 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
363 if (!GV->hasInitializer()) // External globals require no extra code.
366 GVSym->redefineIfPossible();
367 if (GVSym->isDefined() || GVSym->isVariable())
368 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
369 "' is already defined");
371 if (MAI->hasDotTypeDotSizeDirective())
372 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
374 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
376 const DataLayout *DL = TM.getDataLayout();
377 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType());
379 // If the alignment is specified, we *must* obey it. Overaligning a global
380 // with a specified alignment is a prompt way to break globals emitted to
381 // sections and expected to be contiguous (e.g. ObjC metadata).
382 unsigned AlignLog = getGVAlignmentLog2(GV, *DL);
384 for (const HandlerInfo &HI : Handlers) {
385 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
386 HI.Handler->setSymbolSize(GVSym, Size);
389 // Handle common and BSS local symbols (.lcomm).
390 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
391 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
392 unsigned Align = 1 << AlignLog;
394 // Handle common symbols.
395 if (GVKind.isCommon()) {
396 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
400 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
404 // Handle local BSS symbols.
405 if (MAI->hasMachoZeroFillDirective()) {
406 const MCSection *TheSection =
407 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
408 // .zerofill __DATA, __bss, _foo, 400, 5
409 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
413 // Use .lcomm only if it supports user-specified alignment.
414 // Otherwise, while it would still be correct to use .lcomm in some
415 // cases (e.g. when Align == 1), the external assembler might enfore
416 // some -unknown- default alignment behavior, which could cause
417 // spurious differences between external and integrated assembler.
418 // Prefer to simply fall back to .local / .comm in this case.
419 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
421 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
425 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
429 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
431 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
435 const MCSection *TheSection =
436 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
438 // Handle the zerofill directive on darwin, which is a special form of BSS
440 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
441 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
444 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
445 // .zerofill __DATA, __common, _foo, 400, 5
446 OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
450 // Handle thread local data for mach-o which requires us to output an
451 // additional structure of data and mangle the original symbol so that we
452 // can reference it later.
454 // TODO: This should become an "emit thread local global" method on TLOF.
455 // All of this macho specific stuff should be sunk down into TLOFMachO and
456 // stuff like "TLSExtraDataSection" should no longer be part of the parent
457 // TLOF class. This will also make it more obvious that stuff like
458 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
460 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
461 // Emit the .tbss symbol
463 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
465 if (GVKind.isThreadBSS()) {
466 TheSection = getObjFileLowering().getTLSBSSSection();
467 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
468 } else if (GVKind.isThreadData()) {
469 OutStreamer->SwitchSection(TheSection);
471 EmitAlignment(AlignLog, GV);
472 OutStreamer->EmitLabel(MangSym);
474 EmitGlobalConstant(GV->getInitializer());
477 OutStreamer->AddBlankLine();
479 // Emit the variable struct for the runtime.
480 const MCSection *TLVSect
481 = getObjFileLowering().getTLSExtraDataSection();
483 OutStreamer->SwitchSection(TLVSect);
484 // Emit the linkage here.
485 EmitLinkage(GV, GVSym);
486 OutStreamer->EmitLabel(GVSym);
488 // Three pointers in size:
489 // - __tlv_bootstrap - used to make sure support exists
490 // - spare pointer, used when mapped by the runtime
491 // - pointer to mangled symbol above with initializer
492 unsigned PtrSize = DL->getPointerTypeSize(GV->getType());
493 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
495 OutStreamer->EmitIntValue(0, PtrSize);
496 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
498 OutStreamer->AddBlankLine();
502 OutStreamer->SwitchSection(TheSection);
504 EmitLinkage(GV, GVSym);
505 EmitAlignment(AlignLog, GV);
507 OutStreamer->EmitLabel(GVSym);
509 EmitGlobalConstant(GV->getInitializer());
511 if (MAI->hasDotTypeDotSizeDirective())
513 OutStreamer->EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
515 OutStreamer->AddBlankLine();
518 /// EmitFunctionHeader - This method emits the header for the current
520 void AsmPrinter::EmitFunctionHeader() {
521 // Print out constants referenced by the function
524 // Print the 'header' of function.
525 const Function *F = MF->getFunction();
527 OutStreamer->SwitchSection(
528 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
529 EmitVisibility(CurrentFnSym, F->getVisibility());
531 EmitLinkage(F, CurrentFnSym);
532 if (MAI->hasFunctionAlignment())
533 EmitAlignment(MF->getAlignment(), F);
535 if (MAI->hasDotTypeDotSizeDirective())
536 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
539 F->printAsOperand(OutStreamer->GetCommentOS(),
540 /*PrintType=*/false, F->getParent());
541 OutStreamer->GetCommentOS() << '\n';
544 // Emit the prefix data.
545 if (F->hasPrefixData())
546 EmitGlobalConstant(F->getPrefixData());
548 // Emit the CurrentFnSym. This is a virtual function to allow targets to
549 // do their wild and crazy things as required.
550 EmitFunctionEntryLabel();
552 // If the function had address-taken blocks that got deleted, then we have
553 // references to the dangling symbols. Emit them at the start of the function
554 // so that we don't get references to undefined symbols.
555 std::vector<MCSymbol*> DeadBlockSyms;
556 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
557 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
558 OutStreamer->AddComment("Address taken block that was later removed");
559 OutStreamer->EmitLabel(DeadBlockSyms[i]);
562 if (CurrentFnBegin) {
563 if (MAI->useAssignmentForEHBegin()) {
564 MCSymbol *CurPos = OutContext.CreateTempSymbol();
565 OutStreamer->EmitLabel(CurPos);
566 OutStreamer->EmitAssignment(CurrentFnBegin,
567 MCSymbolRefExpr::Create(CurPos, OutContext));
569 OutStreamer->EmitLabel(CurrentFnBegin);
573 // Emit pre-function debug and/or EH information.
574 for (const HandlerInfo &HI : Handlers) {
575 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
576 HI.Handler->beginFunction(MF);
579 // Emit the prologue data.
580 if (F->hasPrologueData())
581 EmitGlobalConstant(F->getPrologueData());
584 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
585 /// function. This can be overridden by targets as required to do custom stuff.
586 void AsmPrinter::EmitFunctionEntryLabel() {
587 CurrentFnSym->redefineIfPossible();
589 // The function label could have already been emitted if two symbols end up
590 // conflicting due to asm renaming. Detect this and emit an error.
591 if (CurrentFnSym->isVariable())
592 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
593 "' is a protected alias");
594 if (CurrentFnSym->isDefined())
595 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
596 "' label emitted multiple times to assembly file");
598 return OutStreamer->EmitLabel(CurrentFnSym);
601 /// emitComments - Pretty-print comments for instructions.
602 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
603 const MachineFunction *MF = MI.getParent()->getParent();
604 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
606 // Check for spills and reloads
609 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
611 // We assume a single instruction only has a spill or reload, not
613 const MachineMemOperand *MMO;
614 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
615 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
616 MMO = *MI.memoperands_begin();
617 CommentOS << MMO->getSize() << "-byte Reload\n";
619 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
620 if (FrameInfo->isSpillSlotObjectIndex(FI))
621 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
622 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
623 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
624 MMO = *MI.memoperands_begin();
625 CommentOS << MMO->getSize() << "-byte Spill\n";
627 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
628 if (FrameInfo->isSpillSlotObjectIndex(FI))
629 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
632 // Check for spill-induced copies
633 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
634 CommentOS << " Reload Reuse\n";
637 /// emitImplicitDef - This method emits the specified machine instruction
638 /// that is an implicit def.
639 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
640 unsigned RegNo = MI->getOperand(0).getReg();
641 OutStreamer->AddComment(Twine("implicit-def: ") +
642 MMI->getContext().getRegisterInfo()->getName(RegNo));
643 OutStreamer->AddBlankLine();
646 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
647 std::string Str = "kill:";
648 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
649 const MachineOperand &Op = MI->getOperand(i);
650 assert(Op.isReg() && "KILL instruction must have only register operands");
652 Str += AP.MMI->getContext().getRegisterInfo()->getName(Op.getReg());
653 Str += (Op.isDef() ? "<def>" : "<kill>");
655 AP.OutStreamer->AddComment(Str);
656 AP.OutStreamer->AddBlankLine();
659 /// emitDebugValueComment - This method handles the target-independent form
660 /// of DBG_VALUE, returning true if it was able to do so. A false return
661 /// means the target will need to handle MI in EmitInstruction.
662 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
663 // This code handles only the 4-operand target-independent form.
664 if (MI->getNumOperands() != 4)
667 SmallString<128> Str;
668 raw_svector_ostream OS(Str);
669 OS << "DEBUG_VALUE: ";
671 const MDLocalVariable *V = MI->getDebugVariable();
672 if (auto *SP = dyn_cast<MDSubprogram>(V->getScope())) {
673 StringRef Name = SP->getDisplayName();
679 const MDExpression *Expr = MI->getDebugExpression();
680 if (Expr->isBitPiece())
681 OS << " [bit_piece offset=" << Expr->getBitPieceOffset()
682 << " size=" << Expr->getBitPieceSize() << "]";
685 // The second operand is only an offset if it's an immediate.
686 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
687 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
689 // Register or immediate value. Register 0 means undef.
690 if (MI->getOperand(0).isFPImm()) {
691 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
692 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
693 OS << (double)APF.convertToFloat();
694 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
695 OS << APF.convertToDouble();
697 // There is no good way to print long double. Convert a copy to
698 // double. Ah well, it's only a comment.
700 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
702 OS << "(long double) " << APF.convertToDouble();
704 } else if (MI->getOperand(0).isImm()) {
705 OS << MI->getOperand(0).getImm();
706 } else if (MI->getOperand(0).isCImm()) {
707 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
710 if (MI->getOperand(0).isReg()) {
711 Reg = MI->getOperand(0).getReg();
713 assert(MI->getOperand(0).isFI() && "Unknown operand type");
714 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
715 Offset += TFI->getFrameIndexReference(*AP.MF,
716 MI->getOperand(0).getIndex(), Reg);
720 // Suppress offset, it is not meaningful here.
722 // NOTE: Want this comment at start of line, don't emit with AddComment.
723 AP.OutStreamer->emitRawComment(OS.str());
728 OS << AP.MMI->getContext().getRegisterInfo()->getName(Reg);
732 OS << '+' << Offset << ']';
734 // NOTE: Want this comment at start of line, don't emit with AddComment.
735 AP.OutStreamer->emitRawComment(OS.str());
739 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
740 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
741 MF->getFunction()->needsUnwindTableEntry())
744 if (MMI->hasDebugInfo())
750 bool AsmPrinter::needsSEHMoves() {
751 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
754 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
755 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
756 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
757 ExceptionHandlingType != ExceptionHandling::ARM)
760 if (needsCFIMoves() == CFI_M_None)
763 const MachineModuleInfo &MMI = MF->getMMI();
764 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
765 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
766 const MCCFIInstruction &CFI = Instrs[CFIIndex];
767 emitCFIInstruction(CFI);
770 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
771 // The operands are the MCSymbol and the frame offset of the allocation.
772 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
773 int FrameOffset = MI.getOperand(1).getImm();
775 // Emit a symbol assignment.
776 OutStreamer->EmitAssignment(FrameAllocSym,
777 MCConstantExpr::Create(FrameOffset, OutContext));
780 /// EmitFunctionBody - This method emits the body and trailer for a
782 void AsmPrinter::EmitFunctionBody() {
783 EmitFunctionHeader();
785 // Emit target-specific gunk before the function body.
786 EmitFunctionBodyStart();
788 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
790 // Print out code for the function.
791 bool HasAnyRealCode = false;
792 for (auto &MBB : *MF) {
793 // Print a label for the basic block.
794 EmitBasicBlockStart(MBB);
795 for (auto &MI : MBB) {
797 // Print the assembly for the instruction.
798 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
799 !MI.isDebugValue()) {
800 HasAnyRealCode = true;
804 if (ShouldPrintDebugScopes) {
805 for (const HandlerInfo &HI : Handlers) {
806 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
807 TimePassesIsEnabled);
808 HI.Handler->beginInstruction(&MI);
813 emitComments(MI, OutStreamer->GetCommentOS());
815 switch (MI.getOpcode()) {
816 case TargetOpcode::CFI_INSTRUCTION:
817 emitCFIInstruction(MI);
820 case TargetOpcode::FRAME_ALLOC:
824 case TargetOpcode::EH_LABEL:
825 case TargetOpcode::GC_LABEL:
826 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
828 case TargetOpcode::INLINEASM:
831 case TargetOpcode::DBG_VALUE:
833 if (!emitDebugValueComment(&MI, *this))
834 EmitInstruction(&MI);
837 case TargetOpcode::IMPLICIT_DEF:
838 if (isVerbose()) emitImplicitDef(&MI);
840 case TargetOpcode::KILL:
841 if (isVerbose()) emitKill(&MI, *this);
844 EmitInstruction(&MI);
848 if (ShouldPrintDebugScopes) {
849 for (const HandlerInfo &HI : Handlers) {
850 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
851 TimePassesIsEnabled);
852 HI.Handler->endInstruction();
857 EmitBasicBlockEnd(MBB);
860 // If the function is empty and the object file uses .subsections_via_symbols,
861 // then we need to emit *something* to the function body to prevent the
862 // labels from collapsing together. Just emit a noop.
863 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
865 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
866 OutStreamer->AddComment("avoids zero-length function");
868 // Targets can opt-out of emitting the noop here by leaving the opcode
870 if (Noop.getOpcode())
871 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
874 const Function *F = MF->getFunction();
875 for (const auto &BB : *F) {
876 if (!BB.hasAddressTaken())
878 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
879 if (Sym->isDefined())
881 OutStreamer->AddComment("Address of block that was removed by CodeGen");
882 OutStreamer->EmitLabel(Sym);
885 // Emit target-specific gunk after the function body.
886 EmitFunctionBodyEnd();
888 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
889 MAI->hasDotTypeDotSizeDirective()) {
890 // Create a symbol for the end of function.
891 CurrentFnEnd = createTempSymbol("func_end");
892 OutStreamer->EmitLabel(CurrentFnEnd);
895 // If the target wants a .size directive for the size of the function, emit
897 if (MAI->hasDotTypeDotSizeDirective()) {
898 // We can get the size as difference between the function label and the
900 const MCExpr *SizeExp =
901 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(CurrentFnEnd, OutContext),
902 MCSymbolRefExpr::Create(CurrentFnSymForSize,
905 OutStreamer->EmitELFSize(CurrentFnSym, SizeExp);
908 for (const HandlerInfo &HI : Handlers) {
909 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
910 HI.Handler->markFunctionEnd();
913 // Print out jump tables referenced by the function.
916 // Emit post-function debug and/or EH information.
917 for (const HandlerInfo &HI : Handlers) {
918 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
919 HI.Handler->endFunction(MF);
923 OutStreamer->AddBlankLine();
926 /// \brief Compute the number of Global Variables that uses a Constant.
927 static unsigned getNumGlobalVariableUses(const Constant *C) {
931 if (isa<GlobalVariable>(C))
934 unsigned NumUses = 0;
935 for (auto *CU : C->users())
936 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
941 /// \brief Only consider global GOT equivalents if at least one user is a
942 /// cstexpr inside an initializer of another global variables. Also, don't
943 /// handle cstexpr inside instructions. During global variable emission,
944 /// candidates are skipped and are emitted later in case at least one cstexpr
945 /// isn't replaced by a PC relative GOT entry access.
946 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
947 unsigned &NumGOTEquivUsers) {
948 // Global GOT equivalents are unnamed private globals with a constant
949 // pointer initializer to another global symbol. They must point to a
950 // GlobalVariable or Function, i.e., as GlobalValue.
951 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
952 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
955 // To be a got equivalent, at least one of its users need to be a constant
956 // expression used by another global variable.
957 for (auto *U : GV->users())
958 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
960 return NumGOTEquivUsers > 0;
963 /// \brief Unnamed constant global variables solely contaning a pointer to
964 /// another globals variable is equivalent to a GOT table entry; it contains the
965 /// the address of another symbol. Optimize it and replace accesses to these
966 /// "GOT equivalents" by using the GOT entry for the final global instead.
967 /// Compute GOT equivalent candidates among all global variables to avoid
968 /// emitting them if possible later on, after it use is replaced by a GOT entry
970 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
971 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
974 for (const auto &G : M.globals()) {
975 unsigned NumGOTEquivUsers = 0;
976 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
979 const MCSymbol *GOTEquivSym = getSymbol(&G);
980 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
984 /// \brief Constant expressions using GOT equivalent globals may not be eligible
985 /// for PC relative GOT entry conversion, in such cases we need to emit such
986 /// globals we previously omitted in EmitGlobalVariable.
987 void AsmPrinter::emitGlobalGOTEquivs() {
988 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
991 SmallVector<const GlobalVariable *, 8> FailedCandidates;
992 for (auto &I : GlobalGOTEquivs) {
993 const GlobalVariable *GV = I.second.first;
994 unsigned Cnt = I.second.second;
996 FailedCandidates.push_back(GV);
998 GlobalGOTEquivs.clear();
1000 for (auto *GV : FailedCandidates)
1001 EmitGlobalVariable(GV);
1004 bool AsmPrinter::doFinalization(Module &M) {
1005 // Set the MachineFunction to nullptr so that we can catch attempted
1006 // accesses to MF specific features at the module level and so that
1007 // we can conditionalize accesses based on whether or not it is nullptr.
1010 // Gather all GOT equivalent globals in the module. We really need two
1011 // passes over the globals: one to compute and another to avoid its emission
1012 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1013 // where the got equivalent shows up before its use.
1014 computeGlobalGOTEquivs(M);
1016 // Emit global variables.
1017 for (const auto &G : M.globals())
1018 EmitGlobalVariable(&G);
1020 // Emit remaining GOT equivalent globals.
1021 emitGlobalGOTEquivs();
1023 // Emit visibility info for declarations
1024 for (const Function &F : M) {
1025 if (!F.isDeclaration())
1027 GlobalValue::VisibilityTypes V = F.getVisibility();
1028 if (V == GlobalValue::DefaultVisibility)
1031 MCSymbol *Name = getSymbol(&F);
1032 EmitVisibility(Name, V, false);
1035 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1037 // Emit module flags.
1038 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1039 M.getModuleFlagsMetadata(ModuleFlags);
1040 if (!ModuleFlags.empty())
1041 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, *Mang, TM);
1043 Triple TT(TM.getTargetTriple());
1044 if (TT.isOSBinFormatELF()) {
1045 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1047 // Output stubs for external and common global variables.
1048 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1049 if (!Stubs.empty()) {
1050 OutStreamer->SwitchSection(TLOF.getDataRelSection());
1051 const DataLayout *DL = TM.getDataLayout();
1053 for (const auto &Stub : Stubs) {
1054 OutStreamer->EmitLabel(Stub.first);
1055 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1056 DL->getPointerSize());
1061 // Make sure we wrote out everything we need.
1062 OutStreamer->Flush();
1064 // Finalize debug and EH information.
1065 for (const HandlerInfo &HI : Handlers) {
1066 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
1067 TimePassesIsEnabled);
1068 HI.Handler->endModule();
1074 // If the target wants to know about weak references, print them all.
1075 if (MAI->getWeakRefDirective()) {
1076 // FIXME: This is not lazy, it would be nice to only print weak references
1077 // to stuff that is actually used. Note that doing so would require targets
1078 // to notice uses in operands (due to constant exprs etc). This should
1079 // happen with the MC stuff eventually.
1081 // Print out module-level global variables here.
1082 for (const auto &G : M.globals()) {
1083 if (!G.hasExternalWeakLinkage())
1085 OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
1088 for (const auto &F : M) {
1089 if (!F.hasExternalWeakLinkage())
1091 OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1095 OutStreamer->AddBlankLine();
1096 for (const auto &Alias : M.aliases()) {
1097 MCSymbol *Name = getSymbol(&Alias);
1099 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1100 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1101 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1102 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1104 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1106 EmitVisibility(Name, Alias.getVisibility());
1108 // Emit the directives as assignments aka .set:
1109 OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1112 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1113 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1114 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1115 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1116 MP->finishAssembly(M, *MI, *this);
1118 // Emit llvm.ident metadata in an '.ident' directive.
1119 EmitModuleIdents(M);
1121 // Emit __morestack address if needed for indirect calls.
1122 if (MMI->usesMorestackAddr()) {
1123 const MCSection *ReadOnlySection =
1124 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
1126 OutStreamer->SwitchSection(ReadOnlySection);
1128 MCSymbol *AddrSymbol =
1129 OutContext.GetOrCreateSymbol(StringRef("__morestack_addr"));
1130 OutStreamer->EmitLabel(AddrSymbol);
1132 unsigned PtrSize = TM.getDataLayout()->getPointerSize(0);
1133 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1137 // If we don't have any trampolines, then we don't require stack memory
1138 // to be executable. Some targets have a directive to declare this.
1139 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1140 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1141 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1142 OutStreamer->SwitchSection(S);
1144 // Allow the target to emit any magic that it wants at the end of the file,
1145 // after everything else has gone out.
1146 EmitEndOfAsmFile(M);
1148 delete Mang; Mang = nullptr;
1151 OutStreamer->Finish();
1152 OutStreamer->reset();
1157 MCSymbol *AsmPrinter::getCurExceptionSym() {
1158 if (!CurExceptionSym)
1159 CurExceptionSym = createTempSymbol("exception");
1160 return CurExceptionSym;
1163 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1165 // Get the function symbol.
1166 CurrentFnSym = getSymbol(MF.getFunction());
1167 CurrentFnSymForSize = CurrentFnSym;
1168 CurrentFnBegin = nullptr;
1169 CurExceptionSym = nullptr;
1170 bool NeedsLocalForSize = MAI->needsLocalForSize();
1171 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1172 NeedsLocalForSize) {
1173 CurrentFnBegin = createTempSymbol("func_begin");
1174 if (NeedsLocalForSize)
1175 CurrentFnSymForSize = CurrentFnBegin;
1179 LI = &getAnalysis<MachineLoopInfo>();
1183 // SectionCPs - Keep track the alignment, constpool entries per Section.
1187 SmallVector<unsigned, 4> CPEs;
1188 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
1192 /// EmitConstantPool - Print to the current output stream assembly
1193 /// representations of the constants in the constant pool MCP. This is
1194 /// used to print out constants which have been "spilled to memory" by
1195 /// the code generator.
1197 void AsmPrinter::EmitConstantPool() {
1198 const MachineConstantPool *MCP = MF->getConstantPool();
1199 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1200 if (CP.empty()) return;
1202 // Calculate sections for constant pool entries. We collect entries to go into
1203 // the same section together to reduce amount of section switch statements.
1204 SmallVector<SectionCPs, 4> CPSections;
1205 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1206 const MachineConstantPoolEntry &CPE = CP[i];
1207 unsigned Align = CPE.getAlignment();
1210 CPE.getSectionKind(TM.getDataLayout());
1212 const Constant *C = nullptr;
1213 if (!CPE.isMachineConstantPoolEntry())
1214 C = CPE.Val.ConstVal;
1216 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C);
1218 // The number of sections are small, just do a linear search from the
1219 // last section to the first.
1221 unsigned SecIdx = CPSections.size();
1222 while (SecIdx != 0) {
1223 if (CPSections[--SecIdx].S == S) {
1229 SecIdx = CPSections.size();
1230 CPSections.push_back(SectionCPs(S, Align));
1233 if (Align > CPSections[SecIdx].Alignment)
1234 CPSections[SecIdx].Alignment = Align;
1235 CPSections[SecIdx].CPEs.push_back(i);
1238 // Now print stuff into the calculated sections.
1239 const MCSection *CurSection = nullptr;
1240 unsigned Offset = 0;
1241 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1242 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1243 unsigned CPI = CPSections[i].CPEs[j];
1244 MCSymbol *Sym = GetCPISymbol(CPI);
1245 if (!Sym->isUndefined())
1248 if (CurSection != CPSections[i].S) {
1249 OutStreamer->SwitchSection(CPSections[i].S);
1250 EmitAlignment(Log2_32(CPSections[i].Alignment));
1251 CurSection = CPSections[i].S;
1255 MachineConstantPoolEntry CPE = CP[CPI];
1257 // Emit inter-object padding for alignment.
1258 unsigned AlignMask = CPE.getAlignment() - 1;
1259 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1260 OutStreamer->EmitZeros(NewOffset - Offset);
1262 Type *Ty = CPE.getType();
1263 Offset = NewOffset +
1264 TM.getDataLayout()->getTypeAllocSize(Ty);
1266 OutStreamer->EmitLabel(Sym);
1267 if (CPE.isMachineConstantPoolEntry())
1268 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1270 EmitGlobalConstant(CPE.Val.ConstVal);
1275 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1276 /// by the current function to the current output stream.
1278 void AsmPrinter::EmitJumpTableInfo() {
1279 const DataLayout *DL = MF->getTarget().getDataLayout();
1280 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1282 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1283 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1284 if (JT.empty()) return;
1286 // Pick the directive to use to print the jump table entries, and switch to
1287 // the appropriate section.
1288 const Function *F = MF->getFunction();
1289 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1290 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1291 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1293 if (JTInDiffSection) {
1294 // Drop it in the readonly section.
1295 const MCSection *ReadOnlySection =
1296 TLOF.getSectionForJumpTable(*F, *Mang, TM);
1297 OutStreamer->SwitchSection(ReadOnlySection);
1300 EmitAlignment(Log2_32(
1301 MJTI->getEntryAlignment(*TM.getDataLayout())));
1303 // Jump tables in code sections are marked with a data_region directive
1304 // where that's supported.
1305 if (!JTInDiffSection)
1306 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1308 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1309 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1311 // If this jump table was deleted, ignore it.
1312 if (JTBBs.empty()) continue;
1314 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1315 /// emit a .set directive for each unique entry.
1316 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1317 MAI->doesSetDirectiveSuppressesReloc()) {
1318 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1319 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1320 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1321 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1322 const MachineBasicBlock *MBB = JTBBs[ii];
1323 if (!EmittedSets.insert(MBB).second)
1326 // .set LJTSet, LBB32-base
1328 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1329 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1330 MCBinaryExpr::CreateSub(LHS, Base,
1335 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1336 // before each jump table. The first label is never referenced, but tells
1337 // the assembler and linker the extents of the jump table object. The
1338 // second label is actually referenced by the code.
1339 if (JTInDiffSection && DL->hasLinkerPrivateGlobalPrefix())
1340 // FIXME: This doesn't have to have any specific name, just any randomly
1341 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1342 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1344 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1346 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1347 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1349 if (!JTInDiffSection)
1350 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1353 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1355 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1356 const MachineBasicBlock *MBB,
1357 unsigned UID) const {
1358 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1359 const MCExpr *Value = nullptr;
1360 switch (MJTI->getEntryKind()) {
1361 case MachineJumpTableInfo::EK_Inline:
1362 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1363 case MachineJumpTableInfo::EK_Custom32:
1364 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1365 MJTI, MBB, UID, OutContext);
1367 case MachineJumpTableInfo::EK_BlockAddress:
1368 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1370 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1372 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1373 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1374 // with a relocation as gp-relative, e.g.:
1376 MCSymbol *MBBSym = MBB->getSymbol();
1377 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1381 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1382 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1383 // with a relocation as gp-relative, e.g.:
1385 MCSymbol *MBBSym = MBB->getSymbol();
1386 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1390 case MachineJumpTableInfo::EK_LabelDifference32: {
1391 // Each entry is the address of the block minus the address of the jump
1392 // table. This is used for PIC jump tables where gprel32 is not supported.
1394 // .word LBB123 - LJTI1_2
1395 // If the .set directive avoids relocations, this is emitted as:
1396 // .set L4_5_set_123, LBB123 - LJTI1_2
1397 // .word L4_5_set_123
1398 if (MAI->doesSetDirectiveSuppressesReloc()) {
1399 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1403 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1404 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1405 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1406 Value = MCBinaryExpr::CreateSub(Value, Base, OutContext);
1411 assert(Value && "Unknown entry kind!");
1413 unsigned EntrySize =
1414 MJTI->getEntrySize(*TM.getDataLayout());
1415 OutStreamer->EmitValue(Value, EntrySize);
1419 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1420 /// special global used by LLVM. If so, emit it and return true, otherwise
1421 /// do nothing and return false.
1422 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1423 if (GV->getName() == "llvm.used") {
1424 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1425 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1429 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1430 if (StringRef(GV->getSection()) == "llvm.metadata" ||
1431 GV->hasAvailableExternallyLinkage())
1434 if (!GV->hasAppendingLinkage()) return false;
1436 assert(GV->hasInitializer() && "Not a special LLVM global!");
1438 if (GV->getName() == "llvm.global_ctors") {
1439 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);
1441 if (TM.getRelocationModel() == Reloc::Static &&
1442 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1443 StringRef Sym(".constructors_used");
1444 OutStreamer->EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1450 if (GV->getName() == "llvm.global_dtors") {
1451 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);
1453 if (TM.getRelocationModel() == Reloc::Static &&
1454 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1455 StringRef Sym(".destructors_used");
1456 OutStreamer->EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1465 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1466 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1467 /// is true, as being used with this directive.
1468 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1469 // Should be an array of 'i8*'.
1470 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1471 const GlobalValue *GV =
1472 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1474 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1480 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
1482 llvm::Constant *Func;
1483 llvm::GlobalValue *ComdatKey;
1487 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1489 void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
1490 // Should be an array of '{ int, void ()* }' structs. The first value is the
1492 if (!isa<ConstantArray>(List)) return;
1494 // Sanity check the structors list.
1495 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1496 if (!InitList) return; // Not an array!
1497 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1498 // FIXME: Only allow the 3-field form in LLVM 4.0.
1499 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1500 return; // Not an array of two or three elements!
1501 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1502 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1503 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1504 return; // Not (int, ptr, ptr).
1506 // Gather the structors in a form that's convenient for sorting by priority.
1507 SmallVector<Structor, 8> Structors;
1508 for (Value *O : InitList->operands()) {
1509 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1510 if (!CS) continue; // Malformed.
1511 if (CS->getOperand(1)->isNullValue())
1512 break; // Found a null terminator, skip the rest.
1513 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1514 if (!Priority) continue; // Malformed.
1515 Structors.push_back(Structor());
1516 Structor &S = Structors.back();
1517 S.Priority = Priority->getLimitedValue(65535);
1518 S.Func = CS->getOperand(1);
1519 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1520 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1523 // Emit the function pointers in the target-specific order
1524 const DataLayout *DL = TM.getDataLayout();
1525 unsigned Align = Log2_32(DL->getPointerPrefAlignment());
1526 std::stable_sort(Structors.begin(), Structors.end(),
1527 [](const Structor &L,
1528 const Structor &R) { return L.Priority < R.Priority; });
1529 for (Structor &S : Structors) {
1530 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1531 const MCSymbol *KeySym = nullptr;
1532 if (GlobalValue *GV = S.ComdatKey) {
1533 if (GV->hasAvailableExternallyLinkage())
1534 // If the associated variable is available_externally, some other TU
1535 // will provide its dynamic initializer.
1538 KeySym = getSymbol(GV);
1540 const MCSection *OutputSection =
1541 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1542 : Obj.getStaticDtorSection(S.Priority, KeySym));
1543 OutStreamer->SwitchSection(OutputSection);
1544 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1545 EmitAlignment(Align);
1546 EmitXXStructor(S.Func);
1550 void AsmPrinter::EmitModuleIdents(Module &M) {
1551 if (!MAI->hasIdentDirective())
1554 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1555 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1556 const MDNode *N = NMD->getOperand(i);
1557 assert(N->getNumOperands() == 1 &&
1558 "llvm.ident metadata entry can have only one operand");
1559 const MDString *S = cast<MDString>(N->getOperand(0));
1560 OutStreamer->EmitIdent(S->getString());
1565 //===--------------------------------------------------------------------===//
1566 // Emission and print routines
1569 /// EmitInt8 - Emit a byte directive and value.
1571 void AsmPrinter::EmitInt8(int Value) const {
1572 OutStreamer->EmitIntValue(Value, 1);
1575 /// EmitInt16 - Emit a short directive and value.
1577 void AsmPrinter::EmitInt16(int Value) const {
1578 OutStreamer->EmitIntValue(Value, 2);
1581 /// EmitInt32 - Emit a long directive and value.
1583 void AsmPrinter::EmitInt32(int Value) const {
1584 OutStreamer->EmitIntValue(Value, 4);
1587 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1588 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1589 /// .set if it avoids relocations.
1590 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1591 unsigned Size) const {
1592 // Get the Hi-Lo expression.
1593 const MCExpr *Diff =
1594 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1595 MCSymbolRefExpr::Create(Lo, OutContext),
1598 if (!MAI->doesSetDirectiveSuppressesReloc()) {
1599 OutStreamer->EmitValue(Diff, Size);
1603 // Otherwise, emit with .set (aka assignment).
1604 MCSymbol *SetLabel = createTempSymbol("set");
1605 OutStreamer->EmitAssignment(SetLabel, Diff);
1606 OutStreamer->EmitSymbolValue(SetLabel, Size);
1609 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1610 /// where the size in bytes of the directive is specified by Size and Label
1611 /// specifies the label. This implicitly uses .set if it is available.
1612 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1614 bool IsSectionRelative) const {
1615 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1616 OutStreamer->EmitCOFFSecRel32(Label);
1620 // Emit Label+Offset (or just Label if Offset is zero)
1621 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
1623 Expr = MCBinaryExpr::CreateAdd(
1624 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
1626 OutStreamer->EmitValue(Expr, Size);
1629 //===----------------------------------------------------------------------===//
1631 // EmitAlignment - Emit an alignment directive to the specified power of
1632 // two boundary. For example, if you pass in 3 here, you will get an 8
1633 // byte alignment. If a global value is specified, and if that global has
1634 // an explicit alignment requested, it will override the alignment request
1635 // if required for correctness.
1637 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1639 NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(),
1642 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1645 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1646 "undefined behavior");
1647 if (getCurrentSection()->getKind().isText())
1648 OutStreamer->EmitCodeAlignment(1u << NumBits);
1650 OutStreamer->EmitValueToAlignment(1u << NumBits);
1653 //===----------------------------------------------------------------------===//
1654 // Constant emission.
1655 //===----------------------------------------------------------------------===//
1657 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1658 MCContext &Ctx = OutContext;
1660 if (CV->isNullValue() || isa<UndefValue>(CV))
1661 return MCConstantExpr::Create(0, Ctx);
1663 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1664 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1666 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1667 return MCSymbolRefExpr::Create(getSymbol(GV), Ctx);
1669 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1670 return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx);
1672 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1674 llvm_unreachable("Unknown constant value to lower!");
1677 if (const MCExpr *RelocExpr
1678 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1681 switch (CE->getOpcode()) {
1683 // If the code isn't optimized, there may be outstanding folding
1684 // opportunities. Attempt to fold the expression using DataLayout as a
1685 // last resort before giving up.
1686 if (Constant *C = ConstantFoldConstantExpression(CE, *TM.getDataLayout()))
1688 return lowerConstant(C);
1690 // Otherwise report the problem to the user.
1693 raw_string_ostream OS(S);
1694 OS << "Unsupported expression in static initializer: ";
1695 CE->printAsOperand(OS, /*PrintType=*/false,
1696 !MF ? nullptr : MF->getFunction()->getParent());
1697 report_fatal_error(OS.str());
1699 case Instruction::GetElementPtr: {
1700 const DataLayout &DL = *TM.getDataLayout();
1702 // Generate a symbolic expression for the byte address
1703 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
1704 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
1706 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1710 int64_t Offset = OffsetAI.getSExtValue();
1711 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1715 case Instruction::Trunc:
1716 // We emit the value and depend on the assembler to truncate the generated
1717 // expression properly. This is important for differences between
1718 // blockaddress labels. Since the two labels are in the same function, it
1719 // is reasonable to treat their delta as a 32-bit value.
1721 case Instruction::BitCast:
1722 return lowerConstant(CE->getOperand(0));
1724 case Instruction::IntToPtr: {
1725 const DataLayout &DL = *TM.getDataLayout();
1727 // Handle casts to pointers by changing them into casts to the appropriate
1728 // integer type. This promotes constant folding and simplifies this code.
1729 Constant *Op = CE->getOperand(0);
1730 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1732 return lowerConstant(Op);
1735 case Instruction::PtrToInt: {
1736 const DataLayout &DL = *TM.getDataLayout();
1738 // Support only foldable casts to/from pointers that can be eliminated by
1739 // changing the pointer to the appropriately sized integer type.
1740 Constant *Op = CE->getOperand(0);
1741 Type *Ty = CE->getType();
1743 const MCExpr *OpExpr = lowerConstant(Op);
1745 // We can emit the pointer value into this slot if the slot is an
1746 // integer slot equal to the size of the pointer.
1747 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1750 // Otherwise the pointer is smaller than the resultant integer, mask off
1751 // the high bits so we are sure to get a proper truncation if the input is
1753 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1754 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1755 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1758 // The MC library also has a right-shift operator, but it isn't consistently
1759 // signed or unsigned between different targets.
1760 case Instruction::Add:
1761 case Instruction::Sub:
1762 case Instruction::Mul:
1763 case Instruction::SDiv:
1764 case Instruction::SRem:
1765 case Instruction::Shl:
1766 case Instruction::And:
1767 case Instruction::Or:
1768 case Instruction::Xor: {
1769 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1770 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1771 switch (CE->getOpcode()) {
1772 default: llvm_unreachable("Unknown binary operator constant cast expr");
1773 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1774 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1775 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1776 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1777 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1778 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1779 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1780 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1781 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1787 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP,
1788 const Constant *BaseCV = nullptr,
1789 uint64_t Offset = 0);
1791 /// isRepeatedByteSequence - Determine whether the given value is
1792 /// composed of a repeated sequence of identical bytes and return the
1793 /// byte value. If it is not a repeated sequence, return -1.
1794 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1795 StringRef Data = V->getRawDataValues();
1796 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1798 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1799 if (Data[i] != C) return -1;
1800 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1804 /// isRepeatedByteSequence - Determine whether the given value is
1805 /// composed of a repeated sequence of identical bytes and return the
1806 /// byte value. If it is not a repeated sequence, return -1.
1807 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
1809 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1810 if (CI->getBitWidth() > 64) return -1;
1813 TM.getDataLayout()->getTypeAllocSize(V->getType());
1814 uint64_t Value = CI->getZExtValue();
1816 // Make sure the constant is at least 8 bits long and has a power
1817 // of 2 bit width. This guarantees the constant bit width is
1818 // always a multiple of 8 bits, avoiding issues with padding out
1819 // to Size and other such corner cases.
1820 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
1822 uint8_t Byte = static_cast<uint8_t>(Value);
1824 for (unsigned i = 1; i < Size; ++i) {
1826 if (static_cast<uint8_t>(Value) != Byte) return -1;
1830 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1831 // Make sure all array elements are sequences of the same repeated
1833 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1834 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
1835 if (Byte == -1) return -1;
1837 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
1838 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
1839 if (ThisByte == -1) return -1;
1840 if (Byte != ThisByte) return -1;
1845 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1846 return isRepeatedByteSequence(CDS);
1851 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
1854 // See if we can aggregate this into a .fill, if so, emit it as such.
1855 int Value = isRepeatedByteSequence(CDS, AP.TM);
1858 AP.TM.getDataLayout()->getTypeAllocSize(
1860 // Don't emit a 1-byte object as a .fill.
1862 return AP.OutStreamer->EmitFill(Bytes, Value);
1865 // If this can be emitted with .ascii/.asciz, emit it as such.
1866 if (CDS->isString())
1867 return AP.OutStreamer->EmitBytes(CDS->getAsString());
1869 // Otherwise, emit the values in successive locations.
1870 unsigned ElementByteSize = CDS->getElementByteSize();
1871 if (isa<IntegerType>(CDS->getElementType())) {
1872 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1874 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
1875 CDS->getElementAsInteger(i));
1876 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
1879 } else if (ElementByteSize == 4) {
1880 // FP Constants are printed as integer constants to avoid losing
1882 assert(CDS->getElementType()->isFloatTy());
1883 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1889 F = CDS->getElementAsFloat(i);
1891 AP.OutStreamer->GetCommentOS() << "float " << F << '\n';
1892 AP.OutStreamer->EmitIntValue(I, 4);
1895 assert(CDS->getElementType()->isDoubleTy());
1896 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1902 F = CDS->getElementAsDouble(i);
1904 AP.OutStreamer->GetCommentOS() << "double " << F << '\n';
1905 AP.OutStreamer->EmitIntValue(I, 8);
1909 const DataLayout &DL = *AP.TM.getDataLayout();
1910 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1911 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1912 CDS->getNumElements();
1913 if (unsigned Padding = Size - EmittedSize)
1914 AP.OutStreamer->EmitZeros(Padding);
1918 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP,
1919 const Constant *BaseCV, uint64_t Offset) {
1920 // See if we can aggregate some values. Make sure it can be
1921 // represented as a series of bytes of the constant value.
1922 int Value = isRepeatedByteSequence(CA, AP.TM);
1923 const DataLayout &DL = *AP.TM.getDataLayout();
1926 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
1927 AP.OutStreamer->EmitFill(Bytes, Value);
1930 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
1931 emitGlobalConstantImpl(CA->getOperand(i), AP, BaseCV, Offset);
1932 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
1937 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
1938 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1939 emitGlobalConstantImpl(CV->getOperand(i), AP);
1941 const DataLayout &DL = *AP.TM.getDataLayout();
1942 unsigned Size = DL.getTypeAllocSize(CV->getType());
1943 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
1944 CV->getType()->getNumElements();
1945 if (unsigned Padding = Size - EmittedSize)
1946 AP.OutStreamer->EmitZeros(Padding);
1949 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP,
1950 const Constant *BaseCV, uint64_t Offset) {
1951 // Print the fields in successive locations. Pad to align if needed!
1952 const DataLayout *DL = AP.TM.getDataLayout();
1953 unsigned Size = DL->getTypeAllocSize(CS->getType());
1954 const StructLayout *Layout = DL->getStructLayout(CS->getType());
1955 uint64_t SizeSoFar = 0;
1956 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1957 const Constant *Field = CS->getOperand(i);
1959 // Print the actual field value.
1960 emitGlobalConstantImpl(Field, AP, BaseCV, Offset+SizeSoFar);
1962 // Check if padding is needed and insert one or more 0s.
1963 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
1964 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1965 - Layout->getElementOffset(i)) - FieldSize;
1966 SizeSoFar += FieldSize + PadSize;
1968 // Insert padding - this may include padding to increase the size of the
1969 // current field up to the ABI size (if the struct is not packed) as well
1970 // as padding to ensure that the next field starts at the right offset.
1971 AP.OutStreamer->EmitZeros(PadSize);
1973 assert(SizeSoFar == Layout->getSizeInBytes() &&
1974 "Layout of constant struct may be incorrect!");
1977 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
1978 APInt API = CFP->getValueAPF().bitcastToAPInt();
1980 // First print a comment with what we think the original floating-point value
1981 // should have been.
1982 if (AP.isVerbose()) {
1983 SmallString<8> StrVal;
1984 CFP->getValueAPF().toString(StrVal);
1987 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
1989 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
1990 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
1993 // Now iterate through the APInt chunks, emitting them in endian-correct
1994 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
1996 unsigned NumBytes = API.getBitWidth() / 8;
1997 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
1998 const uint64_t *p = API.getRawData();
2000 // PPC's long double has odd notions of endianness compared to how LLVM
2001 // handles it: p[0] goes first for *big* endian on PPC.
2002 if (AP.TM.getDataLayout()->isBigEndian() &&
2003 !CFP->getType()->isPPC_FP128Ty()) {
2004 int Chunk = API.getNumWords() - 1;
2007 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2009 for (; Chunk >= 0; --Chunk)
2010 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2013 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2014 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2017 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2020 // Emit the tail padding for the long double.
2021 const DataLayout &DL = *AP.TM.getDataLayout();
2022 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2023 DL.getTypeStoreSize(CFP->getType()));
2026 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2027 const DataLayout *DL = AP.TM.getDataLayout();
2028 unsigned BitWidth = CI->getBitWidth();
2030 // Copy the value as we may massage the layout for constants whose bit width
2031 // is not a multiple of 64-bits.
2032 APInt Realigned(CI->getValue());
2033 uint64_t ExtraBits = 0;
2034 unsigned ExtraBitsSize = BitWidth & 63;
2036 if (ExtraBitsSize) {
2037 // The bit width of the data is not a multiple of 64-bits.
2038 // The extra bits are expected to be at the end of the chunk of the memory.
2040 // * Nothing to be done, just record the extra bits to emit.
2042 // * Record the extra bits to emit.
2043 // * Realign the raw data to emit the chunks of 64-bits.
2044 if (DL->isBigEndian()) {
2045 // Basically the structure of the raw data is a chunk of 64-bits cells:
2046 // 0 1 BitWidth / 64
2047 // [chunk1][chunk2] ... [chunkN].
2048 // The most significant chunk is chunkN and it should be emitted first.
2049 // However, due to the alignment issue chunkN contains useless bits.
2050 // Realign the chunks so that they contain only useless information:
2051 // ExtraBits 0 1 (BitWidth / 64) - 1
2052 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2053 ExtraBits = Realigned.getRawData()[0] &
2054 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2055 Realigned = Realigned.lshr(ExtraBitsSize);
2057 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2060 // We don't expect assemblers to support integer data directives
2061 // for more than 64 bits, so we emit the data in at most 64-bit
2062 // quantities at a time.
2063 const uint64_t *RawData = Realigned.getRawData();
2064 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2065 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
2066 AP.OutStreamer->EmitIntValue(Val, 8);
2069 if (ExtraBitsSize) {
2070 // Emit the extra bits after the 64-bits chunks.
2072 // Emit a directive that fills the expected size.
2073 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(
2075 Size -= (BitWidth / 64) * 8;
2076 assert(Size && Size * 8 >= ExtraBitsSize &&
2077 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2078 == ExtraBits && "Directive too small for extra bits.");
2079 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2083 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2084 /// equivalent global, by a target specific GOT pc relative access to the
2086 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2087 const Constant *BaseCst,
2089 // The global @foo below illustrates a global that uses a got equivalent.
2091 // @bar = global i32 42
2092 // @gotequiv = private unnamed_addr constant i32* @bar
2093 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2094 // i64 ptrtoint (i32* @foo to i64))
2097 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2098 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2101 // foo = cstexpr, where
2102 // cstexpr := <gotequiv> - "." + <cst>
2103 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2105 // After canonicalization by EvaluateAsRelocatable `ME` turns into:
2107 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2108 // gotpcrelcst := <offset from @foo base> + <cst>
2111 if (!(*ME)->EvaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2114 const MCSymbol *GOTEquivSym = &MV.getSymA()->getSymbol();
2115 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2118 const GlobalValue *BaseGV = dyn_cast<GlobalValue>(BaseCst);
2122 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2123 if (BaseSym != &MV.getSymB()->getSymbol())
2126 // Make sure to match:
2128 // gotpcrelcst := <offset from @foo base> + <cst>
2130 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2131 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2132 // if the target knows how to encode it.
2134 int64_t GOTPCRelCst = Offset + MV.getConstant();
2135 if (GOTPCRelCst < 0)
2137 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2140 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2147 // .long gotequiv - "." + <cst>
2149 // is replaced by the target specific equivalent to:
2154 // .long bar@GOTPCREL+<gotpcrelcst>
2156 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2157 const GlobalVariable *GV = Result.first;
2158 int NumUses = (int)Result.second;
2159 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2160 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2161 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2162 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2164 // Update GOT equivalent usage information
2167 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2170 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP,
2171 const Constant *BaseCV, uint64_t Offset) {
2172 const DataLayout *DL = AP.TM.getDataLayout();
2173 uint64_t Size = DL->getTypeAllocSize(CV->getType());
2175 // Globals with sub-elements such as combinations of arrays and structs
2176 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2177 // constant symbol base and the current position with BaseCV and Offset.
2178 if (!BaseCV && CV->hasOneUse())
2179 BaseCV = dyn_cast<Constant>(CV->user_back());
2181 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2182 return AP.OutStreamer->EmitZeros(Size);
2184 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2191 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2192 CI->getZExtValue());
2193 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2196 emitGlobalConstantLargeInt(CI, AP);
2201 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2202 return emitGlobalConstantFP(CFP, AP);
2204 if (isa<ConstantPointerNull>(CV)) {
2205 AP.OutStreamer->EmitIntValue(0, Size);
2209 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2210 return emitGlobalConstantDataSequential(CDS, AP);
2212 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2213 return emitGlobalConstantArray(CVA, AP, BaseCV, Offset);
2215 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2216 return emitGlobalConstantStruct(CVS, AP, BaseCV, Offset);
2218 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2219 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2221 if (CE->getOpcode() == Instruction::BitCast)
2222 return emitGlobalConstantImpl(CE->getOperand(0), AP);
2225 // If the constant expression's size is greater than 64-bits, then we have
2226 // to emit the value in chunks. Try to constant fold the value and emit it
2228 Constant *New = ConstantFoldConstantExpression(CE, *DL);
2229 if (New && New != CE)
2230 return emitGlobalConstantImpl(New, AP);
2234 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2235 return emitGlobalConstantVector(V, AP);
2237 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2238 // thread the streamer with EmitValue.
2239 const MCExpr *ME = AP.lowerConstant(CV);
2241 // Since lowerConstant already folded and got rid of all IR pointer and
2242 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2244 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2245 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2247 AP.OutStreamer->EmitValue(ME, Size);
2250 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2251 void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
2253 TM.getDataLayout()->getTypeAllocSize(CV->getType());
2255 emitGlobalConstantImpl(CV, *this);
2256 else if (MAI->hasSubsectionsViaSymbols()) {
2257 // If the global has zero size, emit a single byte so that two labels don't
2258 // look like they are at the same location.
2259 OutStreamer->EmitIntValue(0, 1);
2263 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2264 // Target doesn't support this yet!
2265 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2268 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2270 OS << '+' << Offset;
2271 else if (Offset < 0)
2275 //===----------------------------------------------------------------------===//
2276 // Symbol Lowering Routines.
2277 //===----------------------------------------------------------------------===//
2279 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2280 return OutContext.createTempSymbol(Name, true);
2283 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2284 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2287 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2288 return MMI->getAddrLabelSymbol(BB);
2291 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2292 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2293 const DataLayout *DL = TM.getDataLayout();
2294 return OutContext.GetOrCreateSymbol
2295 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
2296 + "_" + Twine(CPID));
2299 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2300 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2301 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2304 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2305 /// FIXME: privatize to AsmPrinter.
2306 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2307 const DataLayout *DL = TM.getDataLayout();
2308 return OutContext.GetOrCreateSymbol
2309 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
2310 Twine(UID) + "_set_" + Twine(MBBID));
2313 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2314 StringRef Suffix) const {
2315 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2319 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
2321 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2322 SmallString<60> NameStr;
2323 Mang->getNameWithPrefix(NameStr, Sym);
2324 return OutContext.GetOrCreateSymbol(NameStr);
2329 /// PrintParentLoopComment - Print comments about parent loops of this one.
2330 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2331 unsigned FunctionNumber) {
2333 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2334 OS.indent(Loop->getLoopDepth()*2)
2335 << "Parent Loop BB" << FunctionNumber << "_"
2336 << Loop->getHeader()->getNumber()
2337 << " Depth=" << Loop->getLoopDepth() << '\n';
2341 /// PrintChildLoopComment - Print comments about child loops within
2342 /// the loop for this basic block, with nesting.
2343 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2344 unsigned FunctionNumber) {
2345 // Add child loop information
2346 for (const MachineLoop *CL : *Loop) {
2347 OS.indent(CL->getLoopDepth()*2)
2348 << "Child Loop BB" << FunctionNumber << "_"
2349 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2351 PrintChildLoopComment(OS, CL, FunctionNumber);
2355 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2356 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2357 const MachineLoopInfo *LI,
2358 const AsmPrinter &AP) {
2359 // Add loop depth information
2360 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2363 MachineBasicBlock *Header = Loop->getHeader();
2364 assert(Header && "No header for loop");
2366 // If this block is not a loop header, just print out what is the loop header
2368 if (Header != &MBB) {
2369 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2370 Twine(AP.getFunctionNumber())+"_" +
2371 Twine(Loop->getHeader()->getNumber())+
2372 " Depth="+Twine(Loop->getLoopDepth()));
2376 // Otherwise, it is a loop header. Print out information about child and
2378 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2380 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2383 OS.indent(Loop->getLoopDepth()*2-2);
2388 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2390 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2394 /// EmitBasicBlockStart - This method prints the label for the specified
2395 /// MachineBasicBlock, an alignment (if present) and a comment describing
2396 /// it if appropriate.
2397 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2398 // Emit an alignment directive for this block, if needed.
2399 if (unsigned Align = MBB.getAlignment())
2400 EmitAlignment(Align);
2402 // If the block has its address taken, emit any labels that were used to
2403 // reference the block. It is possible that there is more than one label
2404 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2405 // the references were generated.
2406 if (MBB.hasAddressTaken()) {
2407 const BasicBlock *BB = MBB.getBasicBlock();
2409 OutStreamer->AddComment("Block address taken");
2411 std::vector<MCSymbol*> Symbols = MMI->getAddrLabelSymbolToEmit(BB);
2412 for (auto *Sym : Symbols)
2413 OutStreamer->EmitLabel(Sym);
2416 // Print some verbose block comments.
2418 if (const BasicBlock *BB = MBB.getBasicBlock())
2420 OutStreamer->AddComment("%" + BB->getName());
2421 emitBasicBlockLoopComments(MBB, LI, *this);
2424 // Print the main label for the block.
2425 if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) {
2427 // NOTE: Want this comment at start of line, don't emit with AddComment.
2428 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2431 OutStreamer->EmitLabel(MBB.getSymbol());
2435 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2436 bool IsDefinition) const {
2437 MCSymbolAttr Attr = MCSA_Invalid;
2439 switch (Visibility) {
2441 case GlobalValue::HiddenVisibility:
2443 Attr = MAI->getHiddenVisibilityAttr();
2445 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2447 case GlobalValue::ProtectedVisibility:
2448 Attr = MAI->getProtectedVisibilityAttr();
2452 if (Attr != MCSA_Invalid)
2453 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2456 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2457 /// exactly one predecessor and the control transfer mechanism between
2458 /// the predecessor and this block is a fall-through.
2460 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2461 // If this is a landing pad, it isn't a fall through. If it has no preds,
2462 // then nothing falls through to it.
2463 if (MBB->isLandingPad() || MBB->pred_empty())
2466 // If there isn't exactly one predecessor, it can't be a fall through.
2467 if (MBB->pred_size() > 1)
2470 // The predecessor has to be immediately before this block.
2471 MachineBasicBlock *Pred = *MBB->pred_begin();
2472 if (!Pred->isLayoutSuccessor(MBB))
2475 // If the block is completely empty, then it definitely does fall through.
2479 // Check the terminators in the previous blocks
2480 for (const auto &MI : Pred->terminators()) {
2481 // If it is not a simple branch, we are in a table somewhere.
2482 if (!MI.isBranch() || MI.isIndirectBranch())
2485 // If we are the operands of one of the branches, this is not a fall
2486 // through. Note that targets with delay slots will usually bundle
2487 // terminators with the delay slot instruction.
2488 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2491 if (OP->isMBB() && OP->getMBB() == MBB)
2501 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2502 if (!S.usesMetadata())
2505 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2506 " stackmap formats, please see the documentation for a description of"
2507 " the default format. If you really need a custom serialized format,"
2508 " please file a bug");
2510 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2511 gcp_map_type::iterator GCPI = GCMap.find(&S);
2512 if (GCPI != GCMap.end())
2513 return GCPI->second.get();
2515 const char *Name = S.getName().c_str();
2517 for (GCMetadataPrinterRegistry::iterator
2518 I = GCMetadataPrinterRegistry::begin(),
2519 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2520 if (strcmp(Name, I->getName()) == 0) {
2521 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2523 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2524 return IterBool.first->second.get();
2527 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2530 /// Pin vtable to this file.
2531 AsmPrinterHandler::~AsmPrinterHandler() {}
2533 void AsmPrinterHandler::markFunctionEnd() {}