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/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, TM.Options.MCOptions);
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::Invalid:
271 case WinEH::EncodingType::Itanium:
272 ES = new WinException(this);
278 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
282 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
283 if (!MAI.hasWeakDefCanBeHiddenDirective())
286 return canBeOmittedFromSymbolTable(GV);
289 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
290 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
292 case GlobalValue::CommonLinkage:
293 case GlobalValue::LinkOnceAnyLinkage:
294 case GlobalValue::LinkOnceODRLinkage:
295 case GlobalValue::WeakAnyLinkage:
296 case GlobalValue::WeakODRLinkage:
297 if (MAI->hasWeakDefDirective()) {
299 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
301 if (!canBeHidden(GV, *MAI))
302 // .weak_definition _foo
303 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
305 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
306 } else if (MAI->hasLinkOnceDirective()) {
308 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
309 //NOTE: linkonce is handled by the section the symbol was assigned to.
312 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
315 case GlobalValue::AppendingLinkage:
316 // FIXME: appending linkage variables should go into a section of
317 // their name or something. For now, just emit them as external.
318 case GlobalValue::ExternalLinkage:
319 // If external or appending, declare as a global symbol.
321 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
323 case GlobalValue::PrivateLinkage:
324 case GlobalValue::InternalLinkage:
326 case GlobalValue::AvailableExternallyLinkage:
327 llvm_unreachable("Should never emit this");
328 case GlobalValue::ExternalWeakLinkage:
329 llvm_unreachable("Don't know how to emit these");
331 llvm_unreachable("Unknown linkage type!");
334 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
335 const GlobalValue *GV) const {
336 TM.getNameWithPrefix(Name, GV, *Mang);
339 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
340 return TM.getSymbol(GV, *Mang);
343 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
344 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
345 if (GV->hasInitializer()) {
346 // Check to see if this is a special global used by LLVM, if so, emit it.
347 if (EmitSpecialLLVMGlobal(GV))
350 // Skip the emission of global equivalents. The symbol can be emitted later
351 // on by emitGlobalGOTEquivs in case it turns out to be needed.
352 if (GlobalGOTEquivs.count(getSymbol(GV)))
356 GV->printAsOperand(OutStreamer->GetCommentOS(),
357 /*PrintType=*/false, GV->getParent());
358 OutStreamer->GetCommentOS() << '\n';
362 MCSymbol *GVSym = getSymbol(GV);
363 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
365 if (!GV->hasInitializer()) // External globals require no extra code.
368 GVSym->redefineIfPossible();
369 if (GVSym->isDefined() || GVSym->isVariable())
370 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
371 "' is already defined");
373 if (MAI->hasDotTypeDotSizeDirective())
374 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
376 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
378 const DataLayout *DL = TM.getDataLayout();
379 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType());
381 // If the alignment is specified, we *must* obey it. Overaligning a global
382 // with a specified alignment is a prompt way to break globals emitted to
383 // sections and expected to be contiguous (e.g. ObjC metadata).
384 unsigned AlignLog = getGVAlignmentLog2(GV, *DL);
386 for (const HandlerInfo &HI : Handlers) {
387 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
388 HI.Handler->setSymbolSize(GVSym, Size);
391 // Handle common and BSS local symbols (.lcomm).
392 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
393 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
394 unsigned Align = 1 << AlignLog;
396 // Handle common symbols.
397 if (GVKind.isCommon()) {
398 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
402 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
406 // Handle local BSS symbols.
407 if (MAI->hasMachoZeroFillDirective()) {
408 MCSection *TheSection =
409 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
410 // .zerofill __DATA, __bss, _foo, 400, 5
411 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
415 // Use .lcomm only if it supports user-specified alignment.
416 // Otherwise, while it would still be correct to use .lcomm in some
417 // cases (e.g. when Align == 1), the external assembler might enfore
418 // some -unknown- default alignment behavior, which could cause
419 // spurious differences between external and integrated assembler.
420 // Prefer to simply fall back to .local / .comm in this case.
421 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
423 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
427 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
431 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
433 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
437 MCSection *TheSection =
438 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
440 // Handle the zerofill directive on darwin, which is a special form of BSS
442 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
443 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
446 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
447 // .zerofill __DATA, __common, _foo, 400, 5
448 OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
452 // Handle thread local data for mach-o which requires us to output an
453 // additional structure of data and mangle the original symbol so that we
454 // can reference it later.
456 // TODO: This should become an "emit thread local global" method on TLOF.
457 // All of this macho specific stuff should be sunk down into TLOFMachO and
458 // stuff like "TLSExtraDataSection" should no longer be part of the parent
459 // TLOF class. This will also make it more obvious that stuff like
460 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
462 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
463 // Emit the .tbss symbol
465 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
467 if (GVKind.isThreadBSS()) {
468 TheSection = getObjFileLowering().getTLSBSSSection();
469 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
470 } else if (GVKind.isThreadData()) {
471 OutStreamer->SwitchSection(TheSection);
473 EmitAlignment(AlignLog, GV);
474 OutStreamer->EmitLabel(MangSym);
476 EmitGlobalConstant(GV->getInitializer());
479 OutStreamer->AddBlankLine();
481 // Emit the variable struct for the runtime.
482 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
484 OutStreamer->SwitchSection(TLVSect);
485 // Emit the linkage here.
486 EmitLinkage(GV, GVSym);
487 OutStreamer->EmitLabel(GVSym);
489 // Three pointers in size:
490 // - __tlv_bootstrap - used to make sure support exists
491 // - spare pointer, used when mapped by the runtime
492 // - pointer to mangled symbol above with initializer
493 unsigned PtrSize = DL->getPointerTypeSize(GV->getType());
494 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
496 OutStreamer->EmitIntValue(0, PtrSize);
497 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
499 OutStreamer->AddBlankLine();
503 OutStreamer->SwitchSection(TheSection);
505 EmitLinkage(GV, GVSym);
506 EmitAlignment(AlignLog, GV);
508 OutStreamer->EmitLabel(GVSym);
510 EmitGlobalConstant(GV->getInitializer());
512 if (MAI->hasDotTypeDotSizeDirective())
514 OutStreamer->EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
516 OutStreamer->AddBlankLine();
519 /// EmitFunctionHeader - This method emits the header for the current
521 void AsmPrinter::EmitFunctionHeader() {
522 // Print out constants referenced by the function
525 // Print the 'header' of function.
526 const Function *F = MF->getFunction();
528 OutStreamer->SwitchSection(
529 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
530 EmitVisibility(CurrentFnSym, F->getVisibility());
532 EmitLinkage(F, CurrentFnSym);
533 if (MAI->hasFunctionAlignment())
534 EmitAlignment(MF->getAlignment(), F);
536 if (MAI->hasDotTypeDotSizeDirective())
537 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
540 F->printAsOperand(OutStreamer->GetCommentOS(),
541 /*PrintType=*/false, F->getParent());
542 OutStreamer->GetCommentOS() << '\n';
545 // Emit the prefix data.
546 if (F->hasPrefixData())
547 EmitGlobalConstant(F->getPrefixData());
549 // Emit the CurrentFnSym. This is a virtual function to allow targets to
550 // do their wild and crazy things as required.
551 EmitFunctionEntryLabel();
553 // If the function had address-taken blocks that got deleted, then we have
554 // references to the dangling symbols. Emit them at the start of the function
555 // so that we don't get references to undefined symbols.
556 std::vector<MCSymbol*> DeadBlockSyms;
557 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
558 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
559 OutStreamer->AddComment("Address taken block that was later removed");
560 OutStreamer->EmitLabel(DeadBlockSyms[i]);
563 if (CurrentFnBegin) {
564 if (MAI->useAssignmentForEHBegin()) {
565 MCSymbol *CurPos = OutContext.createTempSymbol();
566 OutStreamer->EmitLabel(CurPos);
567 OutStreamer->EmitAssignment(CurrentFnBegin,
568 MCSymbolRefExpr::Create(CurPos, OutContext));
570 OutStreamer->EmitLabel(CurrentFnBegin);
574 // Emit pre-function debug and/or EH information.
575 for (const HandlerInfo &HI : Handlers) {
576 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
577 HI.Handler->beginFunction(MF);
580 // Emit the prologue data.
581 if (F->hasPrologueData())
582 EmitGlobalConstant(F->getPrologueData());
585 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
586 /// function. This can be overridden by targets as required to do custom stuff.
587 void AsmPrinter::EmitFunctionEntryLabel() {
588 CurrentFnSym->redefineIfPossible();
590 // The function label could have already been emitted if two symbols end up
591 // conflicting due to asm renaming. Detect this and emit an error.
592 if (CurrentFnSym->isVariable())
593 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
594 "' is a protected alias");
595 if (CurrentFnSym->isDefined())
596 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
597 "' label emitted multiple times to assembly file");
599 return OutStreamer->EmitLabel(CurrentFnSym);
602 /// emitComments - Pretty-print comments for instructions.
603 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
604 const MachineFunction *MF = MI.getParent()->getParent();
605 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
607 // Check for spills and reloads
610 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
612 // We assume a single instruction only has a spill or reload, not
614 const MachineMemOperand *MMO;
615 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
616 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
617 MMO = *MI.memoperands_begin();
618 CommentOS << MMO->getSize() << "-byte Reload\n";
620 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
621 if (FrameInfo->isSpillSlotObjectIndex(FI))
622 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
623 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
624 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
625 MMO = *MI.memoperands_begin();
626 CommentOS << MMO->getSize() << "-byte Spill\n";
628 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
629 if (FrameInfo->isSpillSlotObjectIndex(FI))
630 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
633 // Check for spill-induced copies
634 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
635 CommentOS << " Reload Reuse\n";
638 /// emitImplicitDef - This method emits the specified machine instruction
639 /// that is an implicit def.
640 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
641 unsigned RegNo = MI->getOperand(0).getReg();
642 OutStreamer->AddComment(Twine("implicit-def: ") +
643 MMI->getContext().getRegisterInfo()->getName(RegNo));
644 OutStreamer->AddBlankLine();
647 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
648 std::string Str = "kill:";
649 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
650 const MachineOperand &Op = MI->getOperand(i);
651 assert(Op.isReg() && "KILL instruction must have only register operands");
653 Str += AP.MMI->getContext().getRegisterInfo()->getName(Op.getReg());
654 Str += (Op.isDef() ? "<def>" : "<kill>");
656 AP.OutStreamer->AddComment(Str);
657 AP.OutStreamer->AddBlankLine();
660 /// emitDebugValueComment - This method handles the target-independent form
661 /// of DBG_VALUE, returning true if it was able to do so. A false return
662 /// means the target will need to handle MI in EmitInstruction.
663 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
664 // This code handles only the 4-operand target-independent form.
665 if (MI->getNumOperands() != 4)
668 SmallString<128> Str;
669 raw_svector_ostream OS(Str);
670 OS << "DEBUG_VALUE: ";
672 const DILocalVariable *V = MI->getDebugVariable();
673 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
674 StringRef Name = SP->getDisplayName();
680 const DIExpression *Expr = MI->getDebugExpression();
681 if (Expr->isBitPiece())
682 OS << " [bit_piece offset=" << Expr->getBitPieceOffset()
683 << " size=" << Expr->getBitPieceSize() << "]";
686 // The second operand is only an offset if it's an immediate.
687 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
688 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
690 // Register or immediate value. Register 0 means undef.
691 if (MI->getOperand(0).isFPImm()) {
692 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
693 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
694 OS << (double)APF.convertToFloat();
695 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
696 OS << APF.convertToDouble();
698 // There is no good way to print long double. Convert a copy to
699 // double. Ah well, it's only a comment.
701 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
703 OS << "(long double) " << APF.convertToDouble();
705 } else if (MI->getOperand(0).isImm()) {
706 OS << MI->getOperand(0).getImm();
707 } else if (MI->getOperand(0).isCImm()) {
708 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
711 if (MI->getOperand(0).isReg()) {
712 Reg = MI->getOperand(0).getReg();
714 assert(MI->getOperand(0).isFI() && "Unknown operand type");
715 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
716 Offset += TFI->getFrameIndexReference(*AP.MF,
717 MI->getOperand(0).getIndex(), Reg);
721 // Suppress offset, it is not meaningful here.
723 // NOTE: Want this comment at start of line, don't emit with AddComment.
724 AP.OutStreamer->emitRawComment(OS.str());
729 OS << AP.MMI->getContext().getRegisterInfo()->getName(Reg);
733 OS << '+' << Offset << ']';
735 // NOTE: Want this comment at start of line, don't emit with AddComment.
736 AP.OutStreamer->emitRawComment(OS.str());
740 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
741 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
742 MF->getFunction()->needsUnwindTableEntry())
745 if (MMI->hasDebugInfo())
751 bool AsmPrinter::needsSEHMoves() {
752 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
755 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
756 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
757 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
758 ExceptionHandlingType != ExceptionHandling::ARM)
761 if (needsCFIMoves() == CFI_M_None)
764 const MachineModuleInfo &MMI = MF->getMMI();
765 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
766 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
767 const MCCFIInstruction &CFI = Instrs[CFIIndex];
768 emitCFIInstruction(CFI);
771 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
772 // The operands are the MCSymbol and the frame offset of the allocation.
773 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
774 int FrameOffset = MI.getOperand(1).getImm();
776 // Emit a symbol assignment.
777 OutStreamer->EmitAssignment(FrameAllocSym,
778 MCConstantExpr::Create(FrameOffset, OutContext));
781 /// EmitFunctionBody - This method emits the body and trailer for a
783 void AsmPrinter::EmitFunctionBody() {
784 EmitFunctionHeader();
786 // Emit target-specific gunk before the function body.
787 EmitFunctionBodyStart();
789 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
791 // Print out code for the function.
792 bool HasAnyRealCode = false;
793 for (auto &MBB : *MF) {
794 // Print a label for the basic block.
795 EmitBasicBlockStart(MBB);
796 for (auto &MI : MBB) {
798 // Print the assembly for the instruction.
799 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
800 !MI.isDebugValue()) {
801 HasAnyRealCode = true;
805 if (ShouldPrintDebugScopes) {
806 for (const HandlerInfo &HI : Handlers) {
807 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
808 TimePassesIsEnabled);
809 HI.Handler->beginInstruction(&MI);
814 emitComments(MI, OutStreamer->GetCommentOS());
816 switch (MI.getOpcode()) {
817 case TargetOpcode::CFI_INSTRUCTION:
818 emitCFIInstruction(MI);
821 case TargetOpcode::FRAME_ALLOC:
825 case TargetOpcode::EH_LABEL:
826 case TargetOpcode::GC_LABEL:
827 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
829 case TargetOpcode::INLINEASM:
832 case TargetOpcode::DBG_VALUE:
834 if (!emitDebugValueComment(&MI, *this))
835 EmitInstruction(&MI);
838 case TargetOpcode::IMPLICIT_DEF:
839 if (isVerbose()) emitImplicitDef(&MI);
841 case TargetOpcode::KILL:
842 if (isVerbose()) emitKill(&MI, *this);
845 EmitInstruction(&MI);
849 if (ShouldPrintDebugScopes) {
850 for (const HandlerInfo &HI : Handlers) {
851 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
852 TimePassesIsEnabled);
853 HI.Handler->endInstruction();
858 EmitBasicBlockEnd(MBB);
861 // If the function is empty and the object file uses .subsections_via_symbols,
862 // then we need to emit *something* to the function body to prevent the
863 // labels from collapsing together. Just emit a noop.
864 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
866 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
867 OutStreamer->AddComment("avoids zero-length function");
869 // Targets can opt-out of emitting the noop here by leaving the opcode
871 if (Noop.getOpcode())
872 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
875 const Function *F = MF->getFunction();
876 for (const auto &BB : *F) {
877 if (!BB.hasAddressTaken())
879 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
880 if (Sym->isDefined())
882 OutStreamer->AddComment("Address of block that was removed by CodeGen");
883 OutStreamer->EmitLabel(Sym);
886 // Emit target-specific gunk after the function body.
887 EmitFunctionBodyEnd();
889 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
890 MAI->hasDotTypeDotSizeDirective()) {
891 // Create a symbol for the end of function.
892 CurrentFnEnd = createTempSymbol("func_end");
893 OutStreamer->EmitLabel(CurrentFnEnd);
896 // If the target wants a .size directive for the size of the function, emit
898 if (MAI->hasDotTypeDotSizeDirective()) {
899 // We can get the size as difference between the function label and the
901 const MCExpr *SizeExp =
902 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(CurrentFnEnd, OutContext),
903 MCSymbolRefExpr::Create(CurrentFnSymForSize,
906 OutStreamer->EmitELFSize(CurrentFnSym, SizeExp);
909 for (const HandlerInfo &HI : Handlers) {
910 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
911 HI.Handler->markFunctionEnd();
914 // Print out jump tables referenced by the function.
917 // Emit post-function debug and/or EH information.
918 for (const HandlerInfo &HI : Handlers) {
919 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
920 HI.Handler->endFunction(MF);
924 OutStreamer->AddBlankLine();
927 /// \brief Compute the number of Global Variables that uses a Constant.
928 static unsigned getNumGlobalVariableUses(const Constant *C) {
932 if (isa<GlobalVariable>(C))
935 unsigned NumUses = 0;
936 for (auto *CU : C->users())
937 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
942 /// \brief Only consider global GOT equivalents if at least one user is a
943 /// cstexpr inside an initializer of another global variables. Also, don't
944 /// handle cstexpr inside instructions. During global variable emission,
945 /// candidates are skipped and are emitted later in case at least one cstexpr
946 /// isn't replaced by a PC relative GOT entry access.
947 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
948 unsigned &NumGOTEquivUsers) {
949 // Global GOT equivalents are unnamed private globals with a constant
950 // pointer initializer to another global symbol. They must point to a
951 // GlobalVariable or Function, i.e., as GlobalValue.
952 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
953 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
956 // To be a got equivalent, at least one of its users need to be a constant
957 // expression used by another global variable.
958 for (auto *U : GV->users())
959 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
961 return NumGOTEquivUsers > 0;
964 /// \brief Unnamed constant global variables solely contaning a pointer to
965 /// another globals variable is equivalent to a GOT table entry; it contains the
966 /// the address of another symbol. Optimize it and replace accesses to these
967 /// "GOT equivalents" by using the GOT entry for the final global instead.
968 /// Compute GOT equivalent candidates among all global variables to avoid
969 /// emitting them if possible later on, after it use is replaced by a GOT entry
971 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
972 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
975 for (const auto &G : M.globals()) {
976 unsigned NumGOTEquivUsers = 0;
977 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
980 const MCSymbol *GOTEquivSym = getSymbol(&G);
981 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
985 /// \brief Constant expressions using GOT equivalent globals may not be eligible
986 /// for PC relative GOT entry conversion, in such cases we need to emit such
987 /// globals we previously omitted in EmitGlobalVariable.
988 void AsmPrinter::emitGlobalGOTEquivs() {
989 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
992 SmallVector<const GlobalVariable *, 8> FailedCandidates;
993 for (auto &I : GlobalGOTEquivs) {
994 const GlobalVariable *GV = I.second.first;
995 unsigned Cnt = I.second.second;
997 FailedCandidates.push_back(GV);
999 GlobalGOTEquivs.clear();
1001 for (auto *GV : FailedCandidates)
1002 EmitGlobalVariable(GV);
1005 bool AsmPrinter::doFinalization(Module &M) {
1006 // Set the MachineFunction to nullptr so that we can catch attempted
1007 // accesses to MF specific features at the module level and so that
1008 // we can conditionalize accesses based on whether or not it is nullptr.
1011 // Gather all GOT equivalent globals in the module. We really need two
1012 // passes over the globals: one to compute and another to avoid its emission
1013 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1014 // where the got equivalent shows up before its use.
1015 computeGlobalGOTEquivs(M);
1017 // Emit global variables.
1018 for (const auto &G : M.globals())
1019 EmitGlobalVariable(&G);
1021 // Emit remaining GOT equivalent globals.
1022 emitGlobalGOTEquivs();
1024 // Emit visibility info for declarations
1025 for (const Function &F : M) {
1026 if (!F.isDeclaration())
1028 GlobalValue::VisibilityTypes V = F.getVisibility();
1029 if (V == GlobalValue::DefaultVisibility)
1032 MCSymbol *Name = getSymbol(&F);
1033 EmitVisibility(Name, V, false);
1036 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1038 // Emit module flags.
1039 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1040 M.getModuleFlagsMetadata(ModuleFlags);
1041 if (!ModuleFlags.empty())
1042 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, *Mang, TM);
1044 Triple TT(TM.getTargetTriple());
1045 if (TT.isOSBinFormatELF()) {
1046 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1048 // Output stubs for external and common global variables.
1049 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1050 if (!Stubs.empty()) {
1051 OutStreamer->SwitchSection(TLOF.getDataRelSection());
1052 const DataLayout *DL = TM.getDataLayout();
1054 for (const auto &Stub : Stubs) {
1055 OutStreamer->EmitLabel(Stub.first);
1056 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1057 DL->getPointerSize());
1062 // Make sure we wrote out everything we need.
1063 OutStreamer->Flush();
1065 // Finalize debug and EH information.
1066 for (const HandlerInfo &HI : Handlers) {
1067 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
1068 TimePassesIsEnabled);
1069 HI.Handler->endModule();
1075 // If the target wants to know about weak references, print them all.
1076 if (MAI->getWeakRefDirective()) {
1077 // FIXME: This is not lazy, it would be nice to only print weak references
1078 // to stuff that is actually used. Note that doing so would require targets
1079 // to notice uses in operands (due to constant exprs etc). This should
1080 // happen with the MC stuff eventually.
1082 // Print out module-level global variables here.
1083 for (const auto &G : M.globals()) {
1084 if (!G.hasExternalWeakLinkage())
1086 OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
1089 for (const auto &F : M) {
1090 if (!F.hasExternalWeakLinkage())
1092 OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1096 OutStreamer->AddBlankLine();
1097 for (const auto &Alias : M.aliases()) {
1098 MCSymbol *Name = getSymbol(&Alias);
1100 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1101 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1102 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1103 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1105 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1107 EmitVisibility(Name, Alias.getVisibility());
1109 // Emit the directives as assignments aka .set:
1110 OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1113 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1114 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1115 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1116 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1117 MP->finishAssembly(M, *MI, *this);
1119 // Emit llvm.ident metadata in an '.ident' directive.
1120 EmitModuleIdents(M);
1122 // Emit __morestack address if needed for indirect calls.
1123 if (MMI->usesMorestackAddr()) {
1124 MCSection *ReadOnlySection =
1125 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
1127 OutStreamer->SwitchSection(ReadOnlySection);
1129 MCSymbol *AddrSymbol =
1130 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1131 OutStreamer->EmitLabel(AddrSymbol);
1133 unsigned PtrSize = TM.getDataLayout()->getPointerSize(0);
1134 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1138 // If we don't have any trampolines, then we don't require stack memory
1139 // to be executable. Some targets have a directive to declare this.
1140 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1141 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1142 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1143 OutStreamer->SwitchSection(S);
1145 // Allow the target to emit any magic that it wants at the end of the file,
1146 // after everything else has gone out.
1147 EmitEndOfAsmFile(M);
1149 delete Mang; Mang = nullptr;
1152 OutStreamer->Finish();
1153 OutStreamer->reset();
1158 MCSymbol *AsmPrinter::getCurExceptionSym() {
1159 if (!CurExceptionSym)
1160 CurExceptionSym = createTempSymbol("exception");
1161 return CurExceptionSym;
1164 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1166 // Get the function symbol.
1167 CurrentFnSym = getSymbol(MF.getFunction());
1168 CurrentFnSymForSize = CurrentFnSym;
1169 CurrentFnBegin = nullptr;
1170 CurExceptionSym = nullptr;
1171 bool NeedsLocalForSize = MAI->needsLocalForSize();
1172 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1173 NeedsLocalForSize) {
1174 CurrentFnBegin = createTempSymbol("func_begin");
1175 if (NeedsLocalForSize)
1176 CurrentFnSymForSize = CurrentFnBegin;
1180 LI = &getAnalysis<MachineLoopInfo>();
1184 // Keep track the alignment, constpool entries per Section.
1188 SmallVector<unsigned, 4> CPEs;
1189 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1193 /// EmitConstantPool - Print to the current output stream assembly
1194 /// representations of the constants in the constant pool MCP. This is
1195 /// used to print out constants which have been "spilled to memory" by
1196 /// the code generator.
1198 void AsmPrinter::EmitConstantPool() {
1199 const MachineConstantPool *MCP = MF->getConstantPool();
1200 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1201 if (CP.empty()) return;
1203 // Calculate sections for constant pool entries. We collect entries to go into
1204 // the same section together to reduce amount of section switch statements.
1205 SmallVector<SectionCPs, 4> CPSections;
1206 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1207 const MachineConstantPoolEntry &CPE = CP[i];
1208 unsigned Align = CPE.getAlignment();
1211 CPE.getSectionKind(TM.getDataLayout());
1213 const Constant *C = nullptr;
1214 if (!CPE.isMachineConstantPoolEntry())
1215 C = CPE.Val.ConstVal;
1217 MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C);
1219 // The number of sections are small, just do a linear search from the
1220 // last section to the first.
1222 unsigned SecIdx = CPSections.size();
1223 while (SecIdx != 0) {
1224 if (CPSections[--SecIdx].S == S) {
1230 SecIdx = CPSections.size();
1231 CPSections.push_back(SectionCPs(S, Align));
1234 if (Align > CPSections[SecIdx].Alignment)
1235 CPSections[SecIdx].Alignment = Align;
1236 CPSections[SecIdx].CPEs.push_back(i);
1239 // Now print stuff into the calculated sections.
1240 const MCSection *CurSection = nullptr;
1241 unsigned Offset = 0;
1242 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1243 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1244 unsigned CPI = CPSections[i].CPEs[j];
1245 MCSymbol *Sym = GetCPISymbol(CPI);
1246 if (!Sym->isUndefined())
1249 if (CurSection != CPSections[i].S) {
1250 OutStreamer->SwitchSection(CPSections[i].S);
1251 EmitAlignment(Log2_32(CPSections[i].Alignment));
1252 CurSection = CPSections[i].S;
1256 MachineConstantPoolEntry CPE = CP[CPI];
1258 // Emit inter-object padding for alignment.
1259 unsigned AlignMask = CPE.getAlignment() - 1;
1260 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1261 OutStreamer->EmitZeros(NewOffset - Offset);
1263 Type *Ty = CPE.getType();
1264 Offset = NewOffset +
1265 TM.getDataLayout()->getTypeAllocSize(Ty);
1267 OutStreamer->EmitLabel(Sym);
1268 if (CPE.isMachineConstantPoolEntry())
1269 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1271 EmitGlobalConstant(CPE.Val.ConstVal);
1276 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1277 /// by the current function to the current output stream.
1279 void AsmPrinter::EmitJumpTableInfo() {
1280 const DataLayout *DL = MF->getTarget().getDataLayout();
1281 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1283 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1284 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1285 if (JT.empty()) return;
1287 // Pick the directive to use to print the jump table entries, and switch to
1288 // the appropriate section.
1289 const Function *F = MF->getFunction();
1290 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1291 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1292 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1294 if (JTInDiffSection) {
1295 // Drop it in the readonly section.
1296 MCSection *ReadOnlySection = 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 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 if (!MAI->doesDwarfUseRelocationsAcrossSections())
1593 if (OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size))
1596 // Get the Hi-Lo expression.
1597 const MCExpr *Diff =
1598 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1599 MCSymbolRefExpr::Create(Lo, OutContext),
1602 if (!MAI->doesSetDirectiveSuppressesReloc()) {
1603 OutStreamer->EmitValue(Diff, Size);
1607 // Otherwise, emit with .set (aka assignment).
1608 MCSymbol *SetLabel = createTempSymbol("set");
1609 OutStreamer->EmitAssignment(SetLabel, Diff);
1610 OutStreamer->EmitSymbolValue(SetLabel, Size);
1613 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1614 /// where the size in bytes of the directive is specified by Size and Label
1615 /// specifies the label. This implicitly uses .set if it is available.
1616 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1618 bool IsSectionRelative) const {
1619 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1620 OutStreamer->EmitCOFFSecRel32(Label);
1624 // Emit Label+Offset (or just Label if Offset is zero)
1625 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
1627 Expr = MCBinaryExpr::CreateAdd(
1628 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
1630 OutStreamer->EmitValue(Expr, Size);
1633 //===----------------------------------------------------------------------===//
1635 // EmitAlignment - Emit an alignment directive to the specified power of
1636 // two boundary. For example, if you pass in 3 here, you will get an 8
1637 // byte alignment. If a global value is specified, and if that global has
1638 // an explicit alignment requested, it will override the alignment request
1639 // if required for correctness.
1641 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1643 NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(),
1646 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1649 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1650 "undefined behavior");
1651 if (getCurrentSection()->getKind().isText())
1652 OutStreamer->EmitCodeAlignment(1u << NumBits);
1654 OutStreamer->EmitValueToAlignment(1u << NumBits);
1657 //===----------------------------------------------------------------------===//
1658 // Constant emission.
1659 //===----------------------------------------------------------------------===//
1661 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1662 MCContext &Ctx = OutContext;
1664 if (CV->isNullValue() || isa<UndefValue>(CV))
1665 return MCConstantExpr::Create(0, Ctx);
1667 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1668 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1670 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1671 return MCSymbolRefExpr::Create(getSymbol(GV), Ctx);
1673 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1674 return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx);
1676 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1678 llvm_unreachable("Unknown constant value to lower!");
1681 if (const MCExpr *RelocExpr
1682 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1685 switch (CE->getOpcode()) {
1687 // If the code isn't optimized, there may be outstanding folding
1688 // opportunities. Attempt to fold the expression using DataLayout as a
1689 // last resort before giving up.
1690 if (Constant *C = ConstantFoldConstantExpression(CE, *TM.getDataLayout()))
1692 return lowerConstant(C);
1694 // Otherwise report the problem to the user.
1697 raw_string_ostream OS(S);
1698 OS << "Unsupported expression in static initializer: ";
1699 CE->printAsOperand(OS, /*PrintType=*/false,
1700 !MF ? nullptr : MF->getFunction()->getParent());
1701 report_fatal_error(OS.str());
1703 case Instruction::GetElementPtr: {
1704 const DataLayout &DL = *TM.getDataLayout();
1706 // Generate a symbolic expression for the byte address
1707 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
1708 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
1710 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1714 int64_t Offset = OffsetAI.getSExtValue();
1715 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1719 case Instruction::Trunc:
1720 // We emit the value and depend on the assembler to truncate the generated
1721 // expression properly. This is important for differences between
1722 // blockaddress labels. Since the two labels are in the same function, it
1723 // is reasonable to treat their delta as a 32-bit value.
1725 case Instruction::BitCast:
1726 return lowerConstant(CE->getOperand(0));
1728 case Instruction::IntToPtr: {
1729 const DataLayout &DL = *TM.getDataLayout();
1731 // Handle casts to pointers by changing them into casts to the appropriate
1732 // integer type. This promotes constant folding and simplifies this code.
1733 Constant *Op = CE->getOperand(0);
1734 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1736 return lowerConstant(Op);
1739 case Instruction::PtrToInt: {
1740 const DataLayout &DL = *TM.getDataLayout();
1742 // Support only foldable casts to/from pointers that can be eliminated by
1743 // changing the pointer to the appropriately sized integer type.
1744 Constant *Op = CE->getOperand(0);
1745 Type *Ty = CE->getType();
1747 const MCExpr *OpExpr = lowerConstant(Op);
1749 // We can emit the pointer value into this slot if the slot is an
1750 // integer slot equal to the size of the pointer.
1751 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1754 // Otherwise the pointer is smaller than the resultant integer, mask off
1755 // the high bits so we are sure to get a proper truncation if the input is
1757 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1758 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1759 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1762 // The MC library also has a right-shift operator, but it isn't consistently
1763 // signed or unsigned between different targets.
1764 case Instruction::Add:
1765 case Instruction::Sub:
1766 case Instruction::Mul:
1767 case Instruction::SDiv:
1768 case Instruction::SRem:
1769 case Instruction::Shl:
1770 case Instruction::And:
1771 case Instruction::Or:
1772 case Instruction::Xor: {
1773 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1774 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1775 switch (CE->getOpcode()) {
1776 default: llvm_unreachable("Unknown binary operator constant cast expr");
1777 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1778 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1779 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1780 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1781 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1782 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1783 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1784 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1785 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1791 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP,
1792 const Constant *BaseCV = nullptr,
1793 uint64_t Offset = 0);
1795 /// isRepeatedByteSequence - Determine whether the given value is
1796 /// composed of a repeated sequence of identical bytes and return the
1797 /// byte value. If it is not a repeated sequence, return -1.
1798 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1799 StringRef Data = V->getRawDataValues();
1800 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1802 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1803 if (Data[i] != C) return -1;
1804 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1808 /// isRepeatedByteSequence - Determine whether the given value is
1809 /// composed of a repeated sequence of identical bytes and return the
1810 /// byte value. If it is not a repeated sequence, return -1.
1811 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
1813 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1814 if (CI->getBitWidth() > 64) return -1;
1817 TM.getDataLayout()->getTypeAllocSize(V->getType());
1818 uint64_t Value = CI->getZExtValue();
1820 // Make sure the constant is at least 8 bits long and has a power
1821 // of 2 bit width. This guarantees the constant bit width is
1822 // always a multiple of 8 bits, avoiding issues with padding out
1823 // to Size and other such corner cases.
1824 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
1826 uint8_t Byte = static_cast<uint8_t>(Value);
1828 for (unsigned i = 1; i < Size; ++i) {
1830 if (static_cast<uint8_t>(Value) != Byte) return -1;
1834 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1835 // Make sure all array elements are sequences of the same repeated
1837 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1838 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
1839 if (Byte == -1) return -1;
1841 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
1842 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
1843 if (ThisByte == -1) return -1;
1844 if (Byte != ThisByte) return -1;
1849 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1850 return isRepeatedByteSequence(CDS);
1855 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
1858 // See if we can aggregate this into a .fill, if so, emit it as such.
1859 int Value = isRepeatedByteSequence(CDS, AP.TM);
1862 AP.TM.getDataLayout()->getTypeAllocSize(
1864 // Don't emit a 1-byte object as a .fill.
1866 return AP.OutStreamer->EmitFill(Bytes, Value);
1869 // If this can be emitted with .ascii/.asciz, emit it as such.
1870 if (CDS->isString())
1871 return AP.OutStreamer->EmitBytes(CDS->getAsString());
1873 // Otherwise, emit the values in successive locations.
1874 unsigned ElementByteSize = CDS->getElementByteSize();
1875 if (isa<IntegerType>(CDS->getElementType())) {
1876 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1878 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
1879 CDS->getElementAsInteger(i));
1880 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
1883 } else if (ElementByteSize == 4) {
1884 // FP Constants are printed as integer constants to avoid losing
1886 assert(CDS->getElementType()->isFloatTy());
1887 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1893 F = CDS->getElementAsFloat(i);
1895 AP.OutStreamer->GetCommentOS() << "float " << F << '\n';
1896 AP.OutStreamer->EmitIntValue(I, 4);
1899 assert(CDS->getElementType()->isDoubleTy());
1900 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1906 F = CDS->getElementAsDouble(i);
1908 AP.OutStreamer->GetCommentOS() << "double " << F << '\n';
1909 AP.OutStreamer->EmitIntValue(I, 8);
1913 const DataLayout &DL = *AP.TM.getDataLayout();
1914 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1915 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1916 CDS->getNumElements();
1917 if (unsigned Padding = Size - EmittedSize)
1918 AP.OutStreamer->EmitZeros(Padding);
1922 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP,
1923 const Constant *BaseCV, uint64_t Offset) {
1924 // See if we can aggregate some values. Make sure it can be
1925 // represented as a series of bytes of the constant value.
1926 int Value = isRepeatedByteSequence(CA, AP.TM);
1927 const DataLayout &DL = *AP.TM.getDataLayout();
1930 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
1931 AP.OutStreamer->EmitFill(Bytes, Value);
1934 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
1935 emitGlobalConstantImpl(CA->getOperand(i), AP, BaseCV, Offset);
1936 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
1941 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
1942 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1943 emitGlobalConstantImpl(CV->getOperand(i), AP);
1945 const DataLayout &DL = *AP.TM.getDataLayout();
1946 unsigned Size = DL.getTypeAllocSize(CV->getType());
1947 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
1948 CV->getType()->getNumElements();
1949 if (unsigned Padding = Size - EmittedSize)
1950 AP.OutStreamer->EmitZeros(Padding);
1953 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP,
1954 const Constant *BaseCV, uint64_t Offset) {
1955 // Print the fields in successive locations. Pad to align if needed!
1956 const DataLayout *DL = AP.TM.getDataLayout();
1957 unsigned Size = DL->getTypeAllocSize(CS->getType());
1958 const StructLayout *Layout = DL->getStructLayout(CS->getType());
1959 uint64_t SizeSoFar = 0;
1960 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1961 const Constant *Field = CS->getOperand(i);
1963 // Print the actual field value.
1964 emitGlobalConstantImpl(Field, AP, BaseCV, Offset+SizeSoFar);
1966 // Check if padding is needed and insert one or more 0s.
1967 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
1968 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1969 - Layout->getElementOffset(i)) - FieldSize;
1970 SizeSoFar += FieldSize + PadSize;
1972 // Insert padding - this may include padding to increase the size of the
1973 // current field up to the ABI size (if the struct is not packed) as well
1974 // as padding to ensure that the next field starts at the right offset.
1975 AP.OutStreamer->EmitZeros(PadSize);
1977 assert(SizeSoFar == Layout->getSizeInBytes() &&
1978 "Layout of constant struct may be incorrect!");
1981 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
1982 APInt API = CFP->getValueAPF().bitcastToAPInt();
1984 // First print a comment with what we think the original floating-point value
1985 // should have been.
1986 if (AP.isVerbose()) {
1987 SmallString<8> StrVal;
1988 CFP->getValueAPF().toString(StrVal);
1991 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
1993 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
1994 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
1997 // Now iterate through the APInt chunks, emitting them in endian-correct
1998 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2000 unsigned NumBytes = API.getBitWidth() / 8;
2001 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2002 const uint64_t *p = API.getRawData();
2004 // PPC's long double has odd notions of endianness compared to how LLVM
2005 // handles it: p[0] goes first for *big* endian on PPC.
2006 if (AP.TM.getDataLayout()->isBigEndian() &&
2007 !CFP->getType()->isPPC_FP128Ty()) {
2008 int Chunk = API.getNumWords() - 1;
2011 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2013 for (; Chunk >= 0; --Chunk)
2014 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2017 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2018 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2021 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2024 // Emit the tail padding for the long double.
2025 const DataLayout &DL = *AP.TM.getDataLayout();
2026 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2027 DL.getTypeStoreSize(CFP->getType()));
2030 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2031 const DataLayout *DL = AP.TM.getDataLayout();
2032 unsigned BitWidth = CI->getBitWidth();
2034 // Copy the value as we may massage the layout for constants whose bit width
2035 // is not a multiple of 64-bits.
2036 APInt Realigned(CI->getValue());
2037 uint64_t ExtraBits = 0;
2038 unsigned ExtraBitsSize = BitWidth & 63;
2040 if (ExtraBitsSize) {
2041 // The bit width of the data is not a multiple of 64-bits.
2042 // The extra bits are expected to be at the end of the chunk of the memory.
2044 // * Nothing to be done, just record the extra bits to emit.
2046 // * Record the extra bits to emit.
2047 // * Realign the raw data to emit the chunks of 64-bits.
2048 if (DL->isBigEndian()) {
2049 // Basically the structure of the raw data is a chunk of 64-bits cells:
2050 // 0 1 BitWidth / 64
2051 // [chunk1][chunk2] ... [chunkN].
2052 // The most significant chunk is chunkN and it should be emitted first.
2053 // However, due to the alignment issue chunkN contains useless bits.
2054 // Realign the chunks so that they contain only useless information:
2055 // ExtraBits 0 1 (BitWidth / 64) - 1
2056 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2057 ExtraBits = Realigned.getRawData()[0] &
2058 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2059 Realigned = Realigned.lshr(ExtraBitsSize);
2061 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2064 // We don't expect assemblers to support integer data directives
2065 // for more than 64 bits, so we emit the data in at most 64-bit
2066 // quantities at a time.
2067 const uint64_t *RawData = Realigned.getRawData();
2068 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2069 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
2070 AP.OutStreamer->EmitIntValue(Val, 8);
2073 if (ExtraBitsSize) {
2074 // Emit the extra bits after the 64-bits chunks.
2076 // Emit a directive that fills the expected size.
2077 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(
2079 Size -= (BitWidth / 64) * 8;
2080 assert(Size && Size * 8 >= ExtraBitsSize &&
2081 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2082 == ExtraBits && "Directive too small for extra bits.");
2083 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2087 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2088 /// equivalent global, by a target specific GOT pc relative access to the
2090 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2091 const Constant *BaseCst,
2093 // The global @foo below illustrates a global that uses a got equivalent.
2095 // @bar = global i32 42
2096 // @gotequiv = private unnamed_addr constant i32* @bar
2097 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2098 // i64 ptrtoint (i32* @foo to i64))
2101 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2102 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2105 // foo = cstexpr, where
2106 // cstexpr := <gotequiv> - "." + <cst>
2107 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2109 // After canonicalization by EvaluateAsRelocatable `ME` turns into:
2111 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2112 // gotpcrelcst := <offset from @foo base> + <cst>
2115 if (!(*ME)->EvaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2118 const MCSymbol *GOTEquivSym = &MV.getSymA()->getSymbol();
2119 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2122 const GlobalValue *BaseGV = dyn_cast<GlobalValue>(BaseCst);
2126 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2127 if (BaseSym != &MV.getSymB()->getSymbol())
2130 // Make sure to match:
2132 // gotpcrelcst := <offset from @foo base> + <cst>
2134 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2135 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2136 // if the target knows how to encode it.
2138 int64_t GOTPCRelCst = Offset + MV.getConstant();
2139 if (GOTPCRelCst < 0)
2141 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2144 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2151 // .long gotequiv - "." + <cst>
2153 // is replaced by the target specific equivalent to:
2158 // .long bar@GOTPCREL+<gotpcrelcst>
2160 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2161 const GlobalVariable *GV = Result.first;
2162 int NumUses = (int)Result.second;
2163 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2164 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2165 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2166 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2168 // Update GOT equivalent usage information
2171 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2174 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP,
2175 const Constant *BaseCV, uint64_t Offset) {
2176 const DataLayout *DL = AP.TM.getDataLayout();
2177 uint64_t Size = DL->getTypeAllocSize(CV->getType());
2179 // Globals with sub-elements such as combinations of arrays and structs
2180 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2181 // constant symbol base and the current position with BaseCV and Offset.
2182 if (!BaseCV && CV->hasOneUse())
2183 BaseCV = dyn_cast<Constant>(CV->user_back());
2185 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2186 return AP.OutStreamer->EmitZeros(Size);
2188 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2195 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2196 CI->getZExtValue());
2197 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2200 emitGlobalConstantLargeInt(CI, AP);
2205 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2206 return emitGlobalConstantFP(CFP, AP);
2208 if (isa<ConstantPointerNull>(CV)) {
2209 AP.OutStreamer->EmitIntValue(0, Size);
2213 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2214 return emitGlobalConstantDataSequential(CDS, AP);
2216 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2217 return emitGlobalConstantArray(CVA, AP, BaseCV, Offset);
2219 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2220 return emitGlobalConstantStruct(CVS, AP, BaseCV, Offset);
2222 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2223 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2225 if (CE->getOpcode() == Instruction::BitCast)
2226 return emitGlobalConstantImpl(CE->getOperand(0), AP);
2229 // If the constant expression's size is greater than 64-bits, then we have
2230 // to emit the value in chunks. Try to constant fold the value and emit it
2232 Constant *New = ConstantFoldConstantExpression(CE, *DL);
2233 if (New && New != CE)
2234 return emitGlobalConstantImpl(New, AP);
2238 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2239 return emitGlobalConstantVector(V, AP);
2241 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2242 // thread the streamer with EmitValue.
2243 const MCExpr *ME = AP.lowerConstant(CV);
2245 // Since lowerConstant already folded and got rid of all IR pointer and
2246 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2248 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2249 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2251 AP.OutStreamer->EmitValue(ME, Size);
2254 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2255 void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
2257 TM.getDataLayout()->getTypeAllocSize(CV->getType());
2259 emitGlobalConstantImpl(CV, *this);
2260 else if (MAI->hasSubsectionsViaSymbols()) {
2261 // If the global has zero size, emit a single byte so that two labels don't
2262 // look like they are at the same location.
2263 OutStreamer->EmitIntValue(0, 1);
2267 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2268 // Target doesn't support this yet!
2269 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2272 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2274 OS << '+' << Offset;
2275 else if (Offset < 0)
2279 //===----------------------------------------------------------------------===//
2280 // Symbol Lowering Routines.
2281 //===----------------------------------------------------------------------===//
2283 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2284 return OutContext.createTempSymbol(Name, true);
2287 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2288 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2291 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2292 return MMI->getAddrLabelSymbol(BB);
2295 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2296 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2297 const DataLayout *DL = TM.getDataLayout();
2298 return OutContext.getOrCreateSymbol
2299 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
2300 + "_" + Twine(CPID));
2303 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2304 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2305 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2308 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2309 /// FIXME: privatize to AsmPrinter.
2310 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2311 const DataLayout *DL = TM.getDataLayout();
2312 return OutContext.getOrCreateSymbol
2313 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
2314 Twine(UID) + "_set_" + Twine(MBBID));
2317 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2318 StringRef Suffix) const {
2319 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2323 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
2325 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2326 SmallString<60> NameStr;
2327 Mang->getNameWithPrefix(NameStr, Sym);
2328 return OutContext.getOrCreateSymbol(NameStr);
2333 /// PrintParentLoopComment - Print comments about parent loops of this one.
2334 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2335 unsigned FunctionNumber) {
2337 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2338 OS.indent(Loop->getLoopDepth()*2)
2339 << "Parent Loop BB" << FunctionNumber << "_"
2340 << Loop->getHeader()->getNumber()
2341 << " Depth=" << Loop->getLoopDepth() << '\n';
2345 /// PrintChildLoopComment - Print comments about child loops within
2346 /// the loop for this basic block, with nesting.
2347 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2348 unsigned FunctionNumber) {
2349 // Add child loop information
2350 for (const MachineLoop *CL : *Loop) {
2351 OS.indent(CL->getLoopDepth()*2)
2352 << "Child Loop BB" << FunctionNumber << "_"
2353 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2355 PrintChildLoopComment(OS, CL, FunctionNumber);
2359 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2360 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2361 const MachineLoopInfo *LI,
2362 const AsmPrinter &AP) {
2363 // Add loop depth information
2364 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2367 MachineBasicBlock *Header = Loop->getHeader();
2368 assert(Header && "No header for loop");
2370 // If this block is not a loop header, just print out what is the loop header
2372 if (Header != &MBB) {
2373 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2374 Twine(AP.getFunctionNumber())+"_" +
2375 Twine(Loop->getHeader()->getNumber())+
2376 " Depth="+Twine(Loop->getLoopDepth()));
2380 // Otherwise, it is a loop header. Print out information about child and
2382 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2384 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2387 OS.indent(Loop->getLoopDepth()*2-2);
2392 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2394 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2398 /// EmitBasicBlockStart - This method prints the label for the specified
2399 /// MachineBasicBlock, an alignment (if present) and a comment describing
2400 /// it if appropriate.
2401 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2402 // Emit an alignment directive for this block, if needed.
2403 if (unsigned Align = MBB.getAlignment())
2404 EmitAlignment(Align);
2406 // If the block has its address taken, emit any labels that were used to
2407 // reference the block. It is possible that there is more than one label
2408 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2409 // the references were generated.
2410 if (MBB.hasAddressTaken()) {
2411 const BasicBlock *BB = MBB.getBasicBlock();
2413 OutStreamer->AddComment("Block address taken");
2415 std::vector<MCSymbol*> Symbols = MMI->getAddrLabelSymbolToEmit(BB);
2416 for (auto *Sym : Symbols)
2417 OutStreamer->EmitLabel(Sym);
2420 // Print some verbose block comments.
2422 if (const BasicBlock *BB = MBB.getBasicBlock())
2424 OutStreamer->AddComment("%" + BB->getName());
2425 emitBasicBlockLoopComments(MBB, LI, *this);
2428 // Print the main label for the block.
2429 if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) {
2431 // NOTE: Want this comment at start of line, don't emit with AddComment.
2432 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2435 OutStreamer->EmitLabel(MBB.getSymbol());
2439 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2440 bool IsDefinition) const {
2441 MCSymbolAttr Attr = MCSA_Invalid;
2443 switch (Visibility) {
2445 case GlobalValue::HiddenVisibility:
2447 Attr = MAI->getHiddenVisibilityAttr();
2449 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2451 case GlobalValue::ProtectedVisibility:
2452 Attr = MAI->getProtectedVisibilityAttr();
2456 if (Attr != MCSA_Invalid)
2457 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2460 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2461 /// exactly one predecessor and the control transfer mechanism between
2462 /// the predecessor and this block is a fall-through.
2464 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2465 // If this is a landing pad, it isn't a fall through. If it has no preds,
2466 // then nothing falls through to it.
2467 if (MBB->isLandingPad() || MBB->pred_empty())
2470 // If there isn't exactly one predecessor, it can't be a fall through.
2471 if (MBB->pred_size() > 1)
2474 // The predecessor has to be immediately before this block.
2475 MachineBasicBlock *Pred = *MBB->pred_begin();
2476 if (!Pred->isLayoutSuccessor(MBB))
2479 // If the block is completely empty, then it definitely does fall through.
2483 // Check the terminators in the previous blocks
2484 for (const auto &MI : Pred->terminators()) {
2485 // If it is not a simple branch, we are in a table somewhere.
2486 if (!MI.isBranch() || MI.isIndirectBranch())
2489 // If we are the operands of one of the branches, this is not a fall
2490 // through. Note that targets with delay slots will usually bundle
2491 // terminators with the delay slot instruction.
2492 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2495 if (OP->isMBB() && OP->getMBB() == MBB)
2505 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2506 if (!S.usesMetadata())
2509 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2510 " stackmap formats, please see the documentation for a description of"
2511 " the default format. If you really need a custom serialized format,"
2512 " please file a bug");
2514 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2515 gcp_map_type::iterator GCPI = GCMap.find(&S);
2516 if (GCPI != GCMap.end())
2517 return GCPI->second.get();
2519 const char *Name = S.getName().c_str();
2521 for (GCMetadataPrinterRegistry::iterator
2522 I = GCMetadataPrinterRegistry::begin(),
2523 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2524 if (strcmp(Name, I->getName()) == 0) {
2525 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2527 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2528 return IterBool.first->second.get();
2531 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2534 /// Pin vtable to this file.
2535 AsmPrinterHandler::~AsmPrinterHandler() {}
2537 void AsmPrinterHandler::markFunctionEnd() {}