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 #define DEBUG_TYPE "asm-printer"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "DwarfDebug.h"
17 #include "DwarfException.h"
18 #include "llvm/Module.h"
19 #include "llvm/CodeGen/GCMetadataPrinter.h"
20 #include "llvm/CodeGen/MachineConstantPool.h"
21 #include "llvm/CodeGen/MachineFrameInfo.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineJumpTableInfo.h"
24 #include "llvm/CodeGen/MachineLoopInfo.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/Analysis/ConstantFolding.h"
27 #include "llvm/Analysis/DebugInfo.h"
28 #include "llvm/MC/MCAsmInfo.h"
29 #include "llvm/MC/MCContext.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCInst.h"
32 #include "llvm/MC/MCSection.h"
33 #include "llvm/MC/MCStreamer.h"
34 #include "llvm/MC/MCSymbol.h"
35 #include "llvm/Target/Mangler.h"
36 #include "llvm/Target/TargetData.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/Target/TargetLowering.h"
39 #include "llvm/Target/TargetLoweringObjectFile.h"
40 #include "llvm/Target/TargetRegisterInfo.h"
41 #include "llvm/ADT/SmallString.h"
42 #include "llvm/ADT/Statistic.h"
43 #include "llvm/Support/ErrorHandling.h"
44 #include "llvm/Support/Format.h"
45 #include "llvm/Support/Timer.h"
48 static const char *DWARFGroupName = "DWARF Emission";
49 static const char *DbgTimerName = "DWARF Debug Writer";
50 static const char *EHTimerName = "DWARF Exception Writer";
52 STATISTIC(EmittedInsts, "Number of machine instrs printed");
54 char AsmPrinter::ID = 0;
56 typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
57 static gcp_map_type &getGCMap(void *&P) {
59 P = new gcp_map_type();
60 return *(gcp_map_type*)P;
64 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
65 /// value in log2 form. This rounds up to the preferred alignment if possible
67 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const TargetData &TD,
68 unsigned InBits = 0) {
70 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
71 NumBits = TD.getPreferredAlignmentLog(GVar);
73 // If InBits is specified, round it to it.
77 // If the GV has a specified alignment, take it into account.
78 if (GV->getAlignment() == 0)
81 unsigned GVAlign = Log2_32(GV->getAlignment());
83 // If the GVAlign is larger than NumBits, or if we are required to obey
84 // NumBits because the GV has an assigned section, obey it.
85 if (GVAlign > NumBits || GV->hasSection())
93 AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
94 : MachineFunctionPass(&ID),
95 TM(tm), MAI(tm.getMCAsmInfo()),
96 OutContext(Streamer.getContext()),
97 OutStreamer(Streamer),
98 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
99 DD = 0; DE = 0; MMI = 0; LI = 0;
100 GCMetadataPrinters = 0;
101 VerboseAsm = Streamer.isVerboseAsm();
104 AsmPrinter::~AsmPrinter() {
105 assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized");
107 if (GCMetadataPrinters != 0) {
108 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
110 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
113 GCMetadataPrinters = 0;
119 /// getFunctionNumber - Return a unique ID for the current function.
121 unsigned AsmPrinter::getFunctionNumber() const {
122 return MF->getFunctionNumber();
125 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
126 return TM.getTargetLowering()->getObjFileLowering();
130 /// getTargetData - Return information about data layout.
131 const TargetData &AsmPrinter::getTargetData() const {
132 return *TM.getTargetData();
135 /// getCurrentSection() - Return the current section we are emitting to.
136 const MCSection *AsmPrinter::getCurrentSection() const {
137 return OutStreamer.getCurrentSection();
142 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
143 AU.setPreservesAll();
144 MachineFunctionPass::getAnalysisUsage(AU);
145 AU.addRequired<MachineModuleInfo>();
146 AU.addRequired<GCModuleInfo>();
148 AU.addRequired<MachineLoopInfo>();
151 bool AsmPrinter::doInitialization(Module &M) {
152 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
153 MMI->AnalyzeModule(M);
155 // Initialize TargetLoweringObjectFile.
156 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
157 .Initialize(OutContext, TM);
159 Mang = new Mangler(OutContext, *TM.getTargetData());
161 // Allow the target to emit any magic that it wants at the start of the file.
162 EmitStartOfAsmFile(M);
164 // Very minimal debug info. It is ignored if we emit actual debug info. If we
165 // don't, this at least helps the user find where a global came from.
166 if (MAI->hasSingleParameterDotFile()) {
168 OutStreamer.EmitFileDirective(M.getModuleIdentifier());
171 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
172 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
173 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
174 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
175 MP->beginAssembly(*this);
177 // Emit module-level inline asm if it exists.
178 if (!M.getModuleInlineAsm().empty()) {
179 OutStreamer.AddComment("Start of file scope inline assembly");
180 OutStreamer.AddBlankLine();
181 EmitInlineAsm(M.getModuleInlineAsm()+"\n", 0/*no loc cookie*/);
182 OutStreamer.AddComment("End of file scope inline assembly");
183 OutStreamer.AddBlankLine();
186 if (MAI->doesSupportDebugInformation())
187 DD = new DwarfDebug(this, &M);
189 if (MAI->doesSupportExceptionHandling())
190 DE = new DwarfException(this);
195 void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
196 switch ((GlobalValue::LinkageTypes)Linkage) {
197 case GlobalValue::CommonLinkage:
198 case GlobalValue::LinkOnceAnyLinkage:
199 case GlobalValue::LinkOnceODRLinkage:
200 case GlobalValue::WeakAnyLinkage:
201 case GlobalValue::WeakODRLinkage:
202 case GlobalValue::LinkerPrivateWeakLinkage:
203 if (MAI->getWeakDefDirective() != 0) {
205 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
206 // .weak_definition _foo
207 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
208 } else if (MAI->getLinkOnceDirective() != 0) {
210 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
211 //NOTE: linkonce is handled by the section the symbol was assigned to.
214 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
217 case GlobalValue::DLLExportLinkage:
218 case GlobalValue::AppendingLinkage:
219 // FIXME: appending linkage variables should go into a section of
220 // their name or something. For now, just emit them as external.
221 case GlobalValue::ExternalLinkage:
222 // If external or appending, declare as a global symbol.
224 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
226 case GlobalValue::PrivateLinkage:
227 case GlobalValue::InternalLinkage:
228 case GlobalValue::LinkerPrivateLinkage:
231 llvm_unreachable("Unknown linkage type!");
236 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
237 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
238 if (!GV->hasInitializer()) // External globals require no code.
241 // Check to see if this is a special global used by LLVM, if so, emit it.
242 if (EmitSpecialLLVMGlobal(GV))
246 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
247 /*PrintType=*/false, GV->getParent());
248 OutStreamer.GetCommentOS() << '\n';
251 MCSymbol *GVSym = Mang->getSymbol(GV);
252 EmitVisibility(GVSym, GV->getVisibility());
254 if (MAI->hasDotTypeDotSizeDirective())
255 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
257 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
259 const TargetData *TD = TM.getTargetData();
260 uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());
262 // If the alignment is specified, we *must* obey it. Overaligning a global
263 // with a specified alignment is a prompt way to break globals emitted to
264 // sections and expected to be contiguous (e.g. ObjC metadata).
265 unsigned AlignLog = getGVAlignmentLog2(GV, *TD);
267 // Handle common and BSS local symbols (.lcomm).
268 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
269 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
272 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
273 /*PrintType=*/false, GV->getParent());
274 OutStreamer.GetCommentOS() << '\n';
277 // Handle common symbols.
278 if (GVKind.isCommon()) {
280 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
284 // Handle local BSS symbols.
285 if (MAI->hasMachoZeroFillDirective()) {
286 const MCSection *TheSection =
287 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
288 // .zerofill __DATA, __bss, _foo, 400, 5
289 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
293 if (MAI->hasLCOMMDirective()) {
295 OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
300 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
302 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
306 const MCSection *TheSection =
307 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
309 // Handle the zerofill directive on darwin, which is a special form of BSS
311 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
312 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
315 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
316 // .zerofill __DATA, __common, _foo, 400, 5
317 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
321 // Handle thread local data for mach-o which requires us to output an
322 // additional structure of data and mangle the original symbol so that we
323 // can reference it later.
324 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
325 // Emit the .tbss symbol
327 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
329 if (GVKind.isThreadBSS())
330 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
331 else if (GVKind.isThreadData()) {
332 OutStreamer.SwitchSection(TheSection);
334 EmitAlignment(AlignLog, GV);
335 OutStreamer.EmitLabel(MangSym);
337 EmitGlobalConstant(GV->getInitializer());
340 OutStreamer.AddBlankLine();
342 // Emit the variable struct for the runtime.
343 const MCSection *TLVSect
344 = getObjFileLowering().getTLSExtraDataSection();
346 OutStreamer.SwitchSection(TLVSect);
347 // Emit the linkage here.
348 EmitLinkage(GV->getLinkage(), GVSym);
349 OutStreamer.EmitLabel(GVSym);
351 // Three pointers in size:
352 // - __tlv_bootstrap - used to make sure support exists
353 // - spare pointer, used when mapped by the runtime
354 // - pointer to mangled symbol above with initializer
355 unsigned PtrSize = TD->getPointerSizeInBits()/8;
356 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
358 OutStreamer.EmitIntValue(0, PtrSize, 0);
359 OutStreamer.EmitSymbolValue(MangSym, PtrSize, 0);
361 OutStreamer.AddBlankLine();
365 OutStreamer.SwitchSection(TheSection);
367 EmitLinkage(GV->getLinkage(), GVSym);
368 EmitAlignment(AlignLog, GV);
370 OutStreamer.EmitLabel(GVSym);
372 EmitGlobalConstant(GV->getInitializer());
374 if (MAI->hasDotTypeDotSizeDirective())
376 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
378 OutStreamer.AddBlankLine();
381 /// EmitFunctionHeader - This method emits the header for the current
383 void AsmPrinter::EmitFunctionHeader() {
384 // Print out constants referenced by the function
387 // Print the 'header' of function.
388 const Function *F = MF->getFunction();
390 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
391 EmitVisibility(CurrentFnSym, F->getVisibility());
393 EmitLinkage(F->getLinkage(), CurrentFnSym);
394 EmitAlignment(MF->getAlignment(), F);
396 if (MAI->hasDotTypeDotSizeDirective())
397 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
400 WriteAsOperand(OutStreamer.GetCommentOS(), F,
401 /*PrintType=*/false, F->getParent());
402 OutStreamer.GetCommentOS() << '\n';
405 // Emit the CurrentFnSym. This is a virtual function to allow targets to
406 // do their wild and crazy things as required.
407 EmitFunctionEntryLabel();
409 // If the function had address-taken blocks that got deleted, then we have
410 // references to the dangling symbols. Emit them at the start of the function
411 // so that we don't get references to undefined symbols.
412 std::vector<MCSymbol*> DeadBlockSyms;
413 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
414 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
415 OutStreamer.AddComment("Address taken block that was later removed");
416 OutStreamer.EmitLabel(DeadBlockSyms[i]);
419 // Add some workaround for linkonce linkage on Cygwin\MinGW.
420 if (MAI->getLinkOnceDirective() != 0 &&
421 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
422 // FIXME: What is this?
424 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
425 CurrentFnSym->getName());
426 OutStreamer.EmitLabel(FakeStub);
429 // Emit pre-function debug and/or EH information.
431 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
432 DE->BeginFunction(MF);
435 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
436 DD->beginFunction(MF);
440 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
441 /// function. This can be overridden by targets as required to do custom stuff.
442 void AsmPrinter::EmitFunctionEntryLabel() {
443 // The function label could have already been emitted if two symbols end up
444 // conflicting due to asm renaming. Detect this and emit an error.
445 if (CurrentFnSym->isUndefined())
446 return OutStreamer.EmitLabel(CurrentFnSym);
448 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
449 "' label emitted multiple times to assembly file");
453 static void EmitDebugLoc(DebugLoc DL, const MachineFunction *MF,
454 raw_ostream &CommentOS) {
455 const LLVMContext &Ctx = MF->getFunction()->getContext();
456 if (!DL.isUnknown()) { // Print source line info.
457 DIScope Scope(DL.getScope(Ctx));
458 // Omit the directory, because it's likely to be long and uninteresting.
460 CommentOS << Scope.getFilename();
462 CommentOS << "<unknown>";
463 CommentOS << ':' << DL.getLine();
464 if (DL.getCol() != 0)
465 CommentOS << ':' << DL.getCol();
466 DebugLoc InlinedAtDL = DebugLoc::getFromDILocation(DL.getInlinedAt(Ctx));
467 if (!InlinedAtDL.isUnknown()) {
469 EmitDebugLoc(InlinedAtDL, MF, CommentOS);
475 /// EmitComments - Pretty-print comments for instructions.
476 static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
477 const MachineFunction *MF = MI.getParent()->getParent();
478 const TargetMachine &TM = MF->getTarget();
480 DebugLoc DL = MI.getDebugLoc();
481 if (!DL.isUnknown()) { // Print source line info.
482 EmitDebugLoc(DL, MF, CommentOS);
486 // Check for spills and reloads
489 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
491 // We assume a single instruction only has a spill or reload, not
493 const MachineMemOperand *MMO;
494 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
495 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
496 MMO = *MI.memoperands_begin();
497 CommentOS << MMO->getSize() << "-byte Reload\n";
499 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
500 if (FrameInfo->isSpillSlotObjectIndex(FI))
501 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
502 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
503 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
504 MMO = *MI.memoperands_begin();
505 CommentOS << MMO->getSize() << "-byte Spill\n";
507 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
508 if (FrameInfo->isSpillSlotObjectIndex(FI))
509 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
512 // Check for spill-induced copies
513 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
514 CommentOS << " Reload Reuse\n";
517 /// EmitImplicitDef - This method emits the specified machine instruction
518 /// that is an implicit def.
519 static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
520 unsigned RegNo = MI->getOperand(0).getReg();
521 AP.OutStreamer.AddComment(Twine("implicit-def: ") +
522 AP.TM.getRegisterInfo()->getName(RegNo));
523 AP.OutStreamer.AddBlankLine();
526 static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
527 std::string Str = "kill:";
528 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
529 const MachineOperand &Op = MI->getOperand(i);
530 assert(Op.isReg() && "KILL instruction must have only register operands");
532 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
533 Str += (Op.isDef() ? "<def>" : "<kill>");
535 AP.OutStreamer.AddComment(Str);
536 AP.OutStreamer.AddBlankLine();
539 /// EmitDebugValueComment - This method handles the target-independent form
540 /// of DBG_VALUE, returning true if it was able to do so. A false return
541 /// means the target will need to handle MI in EmitInstruction.
542 static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
543 // This code handles only the 3-operand target-independent form.
544 if (MI->getNumOperands() != 3)
547 SmallString<128> Str;
548 raw_svector_ostream OS(Str);
549 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
551 // cast away const; DIetc do not take const operands for some reason.
552 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
553 if (V.getContext().isSubprogram())
554 OS << DISubprogram(V.getContext()).getDisplayName() << ":";
555 OS << V.getName() << " <- ";
557 // Register or immediate value. Register 0 means undef.
558 if (MI->getOperand(0).isFPImm()) {
559 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
560 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
561 OS << (double)APF.convertToFloat();
562 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
563 OS << APF.convertToDouble();
565 // There is no good way to print long double. Convert a copy to
566 // double. Ah well, it's only a comment.
568 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
570 OS << "(long double) " << APF.convertToDouble();
572 } else if (MI->getOperand(0).isImm()) {
573 OS << MI->getOperand(0).getImm();
575 assert(MI->getOperand(0).isReg() && "Unknown operand type");
576 if (MI->getOperand(0).getReg() == 0) {
577 // Suppress offset, it is not meaningful here.
579 // NOTE: Want this comment at start of line, don't emit with AddComment.
580 AP.OutStreamer.EmitRawText(OS.str());
583 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
586 OS << '+' << MI->getOperand(1).getImm();
587 // NOTE: Want this comment at start of line, don't emit with AddComment.
588 AP.OutStreamer.EmitRawText(OS.str());
592 /// EmitFunctionBody - This method emits the body and trailer for a
594 void AsmPrinter::EmitFunctionBody() {
595 // Emit target-specific gunk before the function body.
596 EmitFunctionBodyStart();
598 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
600 // Print out code for the function.
601 bool HasAnyRealCode = false;
602 const MachineInstr *LastMI = 0;
603 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
605 // Print a label for the basic block.
606 EmitBasicBlockStart(I);
607 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
611 // Print the assembly for the instruction.
612 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
613 !II->isDebugValue()) {
614 HasAnyRealCode = true;
618 if (ShouldPrintDebugScopes) {
619 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
624 EmitComments(*II, OutStreamer.GetCommentOS());
626 switch (II->getOpcode()) {
627 case TargetOpcode::PROLOG_LABEL:
628 case TargetOpcode::EH_LABEL:
629 case TargetOpcode::GC_LABEL:
630 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
632 case TargetOpcode::INLINEASM:
635 case TargetOpcode::DBG_VALUE:
637 if (!EmitDebugValueComment(II, *this))
641 case TargetOpcode::IMPLICIT_DEF:
642 if (isVerbose()) EmitImplicitDef(II, *this);
644 case TargetOpcode::KILL:
645 if (isVerbose()) EmitKill(II, *this);
652 if (ShouldPrintDebugScopes) {
653 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
659 // If the last instruction was a prolog label, then we have a situation where
660 // we emitted a prolog but no function body. This results in the ending prolog
661 // label equaling the end of function label and an invalid "row" in the
662 // FDE. We need to emit a noop in this situation so that the FDE's rows are
664 bool RequiresNoop = LastMI && LastMI->getOpcode()==TargetOpcode::PROLOG_LABEL;
666 // If the function is empty and the object file uses .subsections_via_symbols,
667 // then we need to emit *something* to the function body to prevent the
668 // labels from collapsing together. Just emit a noop.
669 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
671 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
672 if (Noop.getOpcode()) {
673 OutStreamer.AddComment("avoids zero-length function");
674 OutStreamer.EmitInstruction(Noop);
675 } else // Target not mc-ized yet.
676 OutStreamer.EmitRawText(StringRef("\tnop\n"));
679 // Emit target-specific gunk after the function body.
680 EmitFunctionBodyEnd();
682 // If the target wants a .size directive for the size of the function, emit
684 if (MAI->hasDotTypeDotSizeDirective()) {
685 // Create a symbol for the end of function, so we can get the size as
686 // difference between the function label and the temp label.
687 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
688 OutStreamer.EmitLabel(FnEndLabel);
690 const MCExpr *SizeExp =
691 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
692 MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
694 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
697 // Emit post-function debug information.
699 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
703 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
708 // Print out jump tables referenced by the function.
711 OutStreamer.AddBlankLine();
714 /// getDebugValueLocation - Get location information encoded by DBG_VALUE
716 MachineLocation AsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
717 // Target specific DBG_VALUE instructions are handled by each target.
718 return MachineLocation();
721 bool AsmPrinter::doFinalization(Module &M) {
722 // Emit global variables.
723 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
725 EmitGlobalVariable(I);
727 // Finalize debug and EH information.
730 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
737 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
743 // If the target wants to know about weak references, print them all.
744 if (MAI->getWeakRefDirective()) {
745 // FIXME: This is not lazy, it would be nice to only print weak references
746 // to stuff that is actually used. Note that doing so would require targets
747 // to notice uses in operands (due to constant exprs etc). This should
748 // happen with the MC stuff eventually.
750 // Print out module-level global variables here.
751 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
753 if (!I->hasExternalWeakLinkage()) continue;
754 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
757 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
758 if (!I->hasExternalWeakLinkage()) continue;
759 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
763 if (MAI->hasSetDirective()) {
764 OutStreamer.AddBlankLine();
765 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
767 MCSymbol *Name = Mang->getSymbol(I);
769 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
770 MCSymbol *Target = Mang->getSymbol(GV);
772 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
773 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
774 else if (I->hasWeakLinkage())
775 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
777 assert(I->hasLocalLinkage() && "Invalid alias linkage");
779 EmitVisibility(Name, I->getVisibility());
781 // Emit the directives as assignments aka .set:
782 OutStreamer.EmitAssignment(Name,
783 MCSymbolRefExpr::Create(Target, OutContext));
787 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
788 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
789 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
790 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
791 MP->finishAssembly(*this);
793 // If we don't have any trampolines, then we don't require stack memory
794 // to be executable. Some targets have a directive to declare this.
795 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
796 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
797 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
798 OutStreamer.SwitchSection(S);
800 // Allow the target to emit any magic that it wants at the end of the file,
801 // after everything else has gone out.
804 delete Mang; Mang = 0;
807 OutStreamer.Finish();
811 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
813 // Get the function symbol.
814 CurrentFnSym = Mang->getSymbol(MF.getFunction());
817 LI = &getAnalysis<MachineLoopInfo>();
821 // SectionCPs - Keep track the alignment, constpool entries per Section.
825 SmallVector<unsigned, 4> CPEs;
826 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
830 /// EmitConstantPool - Print to the current output stream assembly
831 /// representations of the constants in the constant pool MCP. This is
832 /// used to print out constants which have been "spilled to memory" by
833 /// the code generator.
835 void AsmPrinter::EmitConstantPool() {
836 const MachineConstantPool *MCP = MF->getConstantPool();
837 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
838 if (CP.empty()) return;
840 // Calculate sections for constant pool entries. We collect entries to go into
841 // the same section together to reduce amount of section switch statements.
842 SmallVector<SectionCPs, 4> CPSections;
843 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
844 const MachineConstantPoolEntry &CPE = CP[i];
845 unsigned Align = CPE.getAlignment();
848 switch (CPE.getRelocationInfo()) {
849 default: llvm_unreachable("Unknown section kind");
850 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
852 Kind = SectionKind::getReadOnlyWithRelLocal();
855 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
856 case 4: Kind = SectionKind::getMergeableConst4(); break;
857 case 8: Kind = SectionKind::getMergeableConst8(); break;
858 case 16: Kind = SectionKind::getMergeableConst16();break;
859 default: Kind = SectionKind::getMergeableConst(); break;
863 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
865 // The number of sections are small, just do a linear search from the
866 // last section to the first.
868 unsigned SecIdx = CPSections.size();
869 while (SecIdx != 0) {
870 if (CPSections[--SecIdx].S == S) {
876 SecIdx = CPSections.size();
877 CPSections.push_back(SectionCPs(S, Align));
880 if (Align > CPSections[SecIdx].Alignment)
881 CPSections[SecIdx].Alignment = Align;
882 CPSections[SecIdx].CPEs.push_back(i);
885 // Now print stuff into the calculated sections.
886 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
887 OutStreamer.SwitchSection(CPSections[i].S);
888 EmitAlignment(Log2_32(CPSections[i].Alignment));
891 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
892 unsigned CPI = CPSections[i].CPEs[j];
893 MachineConstantPoolEntry CPE = CP[CPI];
895 // Emit inter-object padding for alignment.
896 unsigned AlignMask = CPE.getAlignment() - 1;
897 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
898 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
900 const Type *Ty = CPE.getType();
901 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
903 // Emit the label with a comment on it.
905 OutStreamer.GetCommentOS() << "constant pool ";
906 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
907 MF->getFunction()->getParent());
908 OutStreamer.GetCommentOS() << '\n';
910 OutStreamer.EmitLabel(GetCPISymbol(CPI));
912 if (CPE.isMachineConstantPoolEntry())
913 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
915 EmitGlobalConstant(CPE.Val.ConstVal);
920 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
921 /// by the current function to the current output stream.
923 void AsmPrinter::EmitJumpTableInfo() {
924 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
925 if (MJTI == 0) return;
926 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
927 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
928 if (JT.empty()) return;
930 // Pick the directive to use to print the jump table entries, and switch to
931 // the appropriate section.
932 const Function *F = MF->getFunction();
933 bool JTInDiffSection = false;
934 if (// In PIC mode, we need to emit the jump table to the same section as the
935 // function body itself, otherwise the label differences won't make sense.
936 // FIXME: Need a better predicate for this: what about custom entries?
937 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
938 // We should also do if the section name is NULL or function is declared
939 // in discardable section
940 // FIXME: this isn't the right predicate, should be based on the MCSection
942 F->isWeakForLinker()) {
943 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
945 // Otherwise, drop it in the readonly section.
946 const MCSection *ReadOnlySection =
947 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
948 OutStreamer.SwitchSection(ReadOnlySection);
949 JTInDiffSection = true;
952 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
954 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
955 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
957 // If this jump table was deleted, ignore it.
958 if (JTBBs.empty()) continue;
960 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
961 // .set directive for each unique entry. This reduces the number of
962 // relocations the assembler will generate for the jump table.
963 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
964 MAI->hasSetDirective()) {
965 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
966 const TargetLowering *TLI = TM.getTargetLowering();
967 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
968 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
969 const MachineBasicBlock *MBB = JTBBs[ii];
970 if (!EmittedSets.insert(MBB)) continue;
972 // .set LJTSet, LBB32-base
974 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
975 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
976 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
980 // On some targets (e.g. Darwin) we want to emit two consequtive labels
981 // before each jump table. The first label is never referenced, but tells
982 // the assembler and linker the extents of the jump table object. The
983 // second label is actually referenced by the code.
984 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
985 // FIXME: This doesn't have to have any specific name, just any randomly
986 // named and numbered 'l' label would work. Simplify GetJTISymbol.
987 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
989 OutStreamer.EmitLabel(GetJTISymbol(JTI));
991 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
992 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
996 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
998 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
999 const MachineBasicBlock *MBB,
1000 unsigned UID) const {
1001 const MCExpr *Value = 0;
1002 switch (MJTI->getEntryKind()) {
1003 case MachineJumpTableInfo::EK_Inline:
1004 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
1005 case MachineJumpTableInfo::EK_Custom32:
1006 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1009 case MachineJumpTableInfo::EK_BlockAddress:
1010 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1012 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1014 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1015 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1016 // with a relocation as gp-relative, e.g.:
1018 MCSymbol *MBBSym = MBB->getSymbol();
1019 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1023 case MachineJumpTableInfo::EK_LabelDifference32: {
1024 // EK_LabelDifference32 - Each entry is the address of the block minus
1025 // the address of the jump table. This is used for PIC jump tables where
1026 // gprel32 is not supported. e.g.:
1027 // .word LBB123 - LJTI1_2
1028 // If the .set directive is supported, this is emitted as:
1029 // .set L4_5_set_123, LBB123 - LJTI1_2
1030 // .word L4_5_set_123
1032 // If we have emitted set directives for the jump table entries, print
1033 // them rather than the entries themselves. If we're emitting PIC, then
1034 // emit the table entries as differences between two text section labels.
1035 if (MAI->hasSetDirective()) {
1036 // If we used .set, reference the .set's symbol.
1037 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1041 // Otherwise, use the difference as the jump table entry.
1042 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1043 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1044 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1049 assert(Value && "Unknown entry kind!");
1051 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
1052 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
1056 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1057 /// special global used by LLVM. If so, emit it and return true, otherwise
1058 /// do nothing and return false.
1059 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1060 if (GV->getName() == "llvm.used") {
1061 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1062 EmitLLVMUsedList(GV->getInitializer());
1066 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1067 if (GV->getSection() == "llvm.metadata" ||
1068 GV->hasAvailableExternallyLinkage())
1071 if (!GV->hasAppendingLinkage()) return false;
1073 assert(GV->hasInitializer() && "Not a special LLVM global!");
1075 const TargetData *TD = TM.getTargetData();
1076 unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1077 if (GV->getName() == "llvm.global_ctors") {
1078 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1079 EmitAlignment(Align);
1080 EmitXXStructorList(GV->getInitializer());
1082 if (TM.getRelocationModel() == Reloc::Static &&
1083 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1084 StringRef Sym(".constructors_used");
1085 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1091 if (GV->getName() == "llvm.global_dtors") {
1092 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1093 EmitAlignment(Align);
1094 EmitXXStructorList(GV->getInitializer());
1096 if (TM.getRelocationModel() == Reloc::Static &&
1097 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1098 StringRef Sym(".destructors_used");
1099 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1108 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1109 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1110 /// is true, as being used with this directive.
1111 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1112 // Should be an array of 'i8*'.
1113 ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1114 if (InitList == 0) return;
1116 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1117 const GlobalValue *GV =
1118 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1119 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1120 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1124 /// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
1125 /// function pointers, ignoring the init priority.
1126 void AsmPrinter::EmitXXStructorList(Constant *List) {
1127 // Should be an array of '{ int, void ()* }' structs. The first value is the
1128 // init priority, which we ignore.
1129 if (!isa<ConstantArray>(List)) return;
1130 ConstantArray *InitList = cast<ConstantArray>(List);
1131 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1132 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1133 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
1135 if (CS->getOperand(1)->isNullValue())
1136 return; // Found a null terminator, exit printing.
1137 // Emit the function pointer.
1138 EmitGlobalConstant(CS->getOperand(1));
1142 //===--------------------------------------------------------------------===//
1143 // Emission and print routines
1146 /// EmitInt8 - Emit a byte directive and value.
1148 void AsmPrinter::EmitInt8(int Value) const {
1149 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1152 /// EmitInt16 - Emit a short directive and value.
1154 void AsmPrinter::EmitInt16(int Value) const {
1155 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1158 /// EmitInt32 - Emit a long directive and value.
1160 void AsmPrinter::EmitInt32(int Value) const {
1161 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1164 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1165 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1166 /// labels. This implicitly uses .set if it is available.
1167 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1168 unsigned Size) const {
1169 // Get the Hi-Lo expression.
1170 const MCExpr *Diff =
1171 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1172 MCSymbolRefExpr::Create(Lo, OutContext),
1175 if (!MAI->hasSetDirective()) {
1176 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1180 // Otherwise, emit with .set (aka assignment).
1181 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1182 OutStreamer.EmitAssignment(SetLabel, Diff);
1183 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1186 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1187 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1188 /// specify the labels. This implicitly uses .set if it is available.
1189 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1190 const MCSymbol *Lo, unsigned Size)
1193 // Emit Hi+Offset - Lo
1194 // Get the Hi+Offset expression.
1195 const MCExpr *Plus =
1196 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1197 MCConstantExpr::Create(Offset, OutContext),
1200 // Get the Hi+Offset-Lo expression.
1201 const MCExpr *Diff =
1202 MCBinaryExpr::CreateSub(Plus,
1203 MCSymbolRefExpr::Create(Lo, OutContext),
1206 if (!MAI->hasSetDirective())
1207 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1209 // Otherwise, emit with .set (aka assignment).
1210 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1211 OutStreamer.EmitAssignment(SetLabel, Diff);
1212 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1217 //===----------------------------------------------------------------------===//
1219 // EmitAlignment - Emit an alignment directive to the specified power of
1220 // two boundary. For example, if you pass in 3 here, you will get an 8
1221 // byte alignment. If a global value is specified, and if that global has
1222 // an explicit alignment requested, it will override the alignment request
1223 // if required for correctness.
1225 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1226 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
1228 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1230 if (getCurrentSection()->getKind().isText())
1231 OutStreamer.EmitCodeAlignment(1 << NumBits);
1233 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1236 //===----------------------------------------------------------------------===//
1237 // Constant emission.
1238 //===----------------------------------------------------------------------===//
1240 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1242 static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1243 MCContext &Ctx = AP.OutContext;
1245 if (CV->isNullValue() || isa<UndefValue>(CV))
1246 return MCConstantExpr::Create(0, Ctx);
1248 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1249 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1251 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1252 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1253 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1254 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1256 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1258 llvm_unreachable("Unknown constant value to lower!");
1259 return MCConstantExpr::Create(0, Ctx);
1262 switch (CE->getOpcode()) {
1264 // If the code isn't optimized, there may be outstanding folding
1265 // opportunities. Attempt to fold the expression using TargetData as a
1266 // last resort before giving up.
1268 ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1270 return LowerConstant(C, AP);
1274 llvm_unreachable("FIXME: Don't support this constant expr");
1275 case Instruction::GetElementPtr: {
1276 const TargetData &TD = *AP.TM.getTargetData();
1277 // Generate a symbolic expression for the byte address
1278 const Constant *PtrVal = CE->getOperand(0);
1279 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1280 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1283 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1287 // Truncate/sext the offset to the pointer size.
1288 if (TD.getPointerSizeInBits() != 64) {
1289 int SExtAmount = 64-TD.getPointerSizeInBits();
1290 Offset = (Offset << SExtAmount) >> SExtAmount;
1293 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1297 case Instruction::Trunc:
1298 // We emit the value and depend on the assembler to truncate the generated
1299 // expression properly. This is important for differences between
1300 // blockaddress labels. Since the two labels are in the same function, it
1301 // is reasonable to treat their delta as a 32-bit value.
1303 case Instruction::BitCast:
1304 return LowerConstant(CE->getOperand(0), AP);
1306 case Instruction::IntToPtr: {
1307 const TargetData &TD = *AP.TM.getTargetData();
1308 // Handle casts to pointers by changing them into casts to the appropriate
1309 // integer type. This promotes constant folding and simplifies this code.
1310 Constant *Op = CE->getOperand(0);
1311 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1313 return LowerConstant(Op, AP);
1316 case Instruction::PtrToInt: {
1317 const TargetData &TD = *AP.TM.getTargetData();
1318 // Support only foldable casts to/from pointers that can be eliminated by
1319 // changing the pointer to the appropriately sized integer type.
1320 Constant *Op = CE->getOperand(0);
1321 const Type *Ty = CE->getType();
1323 const MCExpr *OpExpr = LowerConstant(Op, AP);
1325 // We can emit the pointer value into this slot if the slot is an
1326 // integer slot equal to the size of the pointer.
1327 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1330 // Otherwise the pointer is smaller than the resultant integer, mask off
1331 // the high bits so we are sure to get a proper truncation if the input is
1333 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1334 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1335 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1338 // The MC library also has a right-shift operator, but it isn't consistently
1339 // signed or unsigned between different targets.
1340 case Instruction::Add:
1341 case Instruction::Sub:
1342 case Instruction::Mul:
1343 case Instruction::SDiv:
1344 case Instruction::SRem:
1345 case Instruction::Shl:
1346 case Instruction::And:
1347 case Instruction::Or:
1348 case Instruction::Xor: {
1349 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1350 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1351 switch (CE->getOpcode()) {
1352 default: llvm_unreachable("Unknown binary operator constant cast expr");
1353 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1354 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1355 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1356 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1357 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1358 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1359 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1360 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1361 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1367 static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1370 static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1372 if (AddrSpace != 0 || !CA->isString()) {
1373 // Not a string. Print the values in successive locations
1374 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1375 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1379 // Otherwise, it can be emitted as .ascii.
1380 SmallVector<char, 128> TmpVec;
1381 TmpVec.reserve(CA->getNumOperands());
1382 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1383 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1385 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1388 static void EmitGlobalConstantVector(const ConstantVector *CV,
1389 unsigned AddrSpace, AsmPrinter &AP) {
1390 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1391 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1394 static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1395 unsigned AddrSpace, AsmPrinter &AP) {
1396 // Print the fields in successive locations. Pad to align if needed!
1397 const TargetData *TD = AP.TM.getTargetData();
1398 unsigned Size = TD->getTypeAllocSize(CS->getType());
1399 const StructLayout *Layout = TD->getStructLayout(CS->getType());
1400 uint64_t SizeSoFar = 0;
1401 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1402 const Constant *Field = CS->getOperand(i);
1404 // Check if padding is needed and insert one or more 0s.
1405 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1406 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1407 - Layout->getElementOffset(i)) - FieldSize;
1408 SizeSoFar += FieldSize + PadSize;
1410 // Now print the actual field value.
1411 EmitGlobalConstantImpl(Field, AddrSpace, AP);
1413 // Insert padding - this may include padding to increase the size of the
1414 // current field up to the ABI size (if the struct is not packed) as well
1415 // as padding to ensure that the next field starts at the right offset.
1416 AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1418 assert(SizeSoFar == Layout->getSizeInBytes() &&
1419 "Layout of constant struct may be incorrect!");
1422 static void EmitGlobalConstantUnion(const ConstantUnion *CU,
1423 unsigned AddrSpace, AsmPrinter &AP) {
1424 const TargetData *TD = AP.TM.getTargetData();
1425 unsigned Size = TD->getTypeAllocSize(CU->getType());
1427 const Constant *Contents = CU->getOperand(0);
1428 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType());
1430 // Print the actually filled part
1431 EmitGlobalConstantImpl(Contents, AddrSpace, AP);
1433 // And pad with enough zeroes
1434 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace);
1437 static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1439 // FP Constants are printed as integer constants to avoid losing
1441 if (CFP->getType()->isDoubleTy()) {
1442 if (AP.isVerbose()) {
1443 double Val = CFP->getValueAPF().convertToDouble();
1444 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1447 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1448 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1452 if (CFP->getType()->isFloatTy()) {
1453 if (AP.isVerbose()) {
1454 float Val = CFP->getValueAPF().convertToFloat();
1455 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1457 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1458 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1462 if (CFP->getType()->isX86_FP80Ty()) {
1463 // all long double variants are printed as hex
1464 // API needed to prevent premature destruction
1465 APInt API = CFP->getValueAPF().bitcastToAPInt();
1466 const uint64_t *p = API.getRawData();
1467 if (AP.isVerbose()) {
1468 // Convert to double so we can print the approximate val as a comment.
1469 APFloat DoubleVal = CFP->getValueAPF();
1471 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1473 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1474 << DoubleVal.convertToDouble() << '\n';
1477 if (AP.TM.getTargetData()->isBigEndian()) {
1478 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1479 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1481 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1482 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1485 // Emit the tail padding for the long double.
1486 const TargetData &TD = *AP.TM.getTargetData();
1487 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1488 TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1492 assert(CFP->getType()->isPPC_FP128Ty() &&
1493 "Floating point constant type not handled");
1494 // All long double variants are printed as hex
1495 // API needed to prevent premature destruction.
1496 APInt API = CFP->getValueAPF().bitcastToAPInt();
1497 const uint64_t *p = API.getRawData();
1498 if (AP.TM.getTargetData()->isBigEndian()) {
1499 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1500 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1502 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1503 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1507 static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1508 unsigned AddrSpace, AsmPrinter &AP) {
1509 const TargetData *TD = AP.TM.getTargetData();
1510 unsigned BitWidth = CI->getBitWidth();
1511 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1513 // We don't expect assemblers to support integer data directives
1514 // for more than 64 bits, so we emit the data in at most 64-bit
1515 // quantities at a time.
1516 const uint64_t *RawData = CI->getValue().getRawData();
1517 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1518 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1519 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1523 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1525 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1526 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1527 return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1530 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1531 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1538 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1539 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1542 EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1547 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1548 return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1550 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1551 return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1553 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1554 return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1556 if (isa<ConstantPointerNull>(CV)) {
1557 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1558 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1562 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV))
1563 return EmitGlobalConstantUnion(CVU, AddrSpace, AP);
1565 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1566 return EmitGlobalConstantVector(V, AddrSpace, AP);
1568 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
1569 // thread the streamer with EmitValue.
1570 AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1571 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1575 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1576 void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1577 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1579 EmitGlobalConstantImpl(CV, AddrSpace, *this);
1580 else if (MAI->hasSubsectionsViaSymbols()) {
1581 // If the global has zero size, emit a single byte so that two labels don't
1582 // look like they are at the same location.
1583 OutStreamer.EmitIntValue(0, 1, AddrSpace);
1587 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1588 // Target doesn't support this yet!
1589 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1592 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1594 OS << '+' << Offset;
1595 else if (Offset < 0)
1599 //===----------------------------------------------------------------------===//
1600 // Symbol Lowering Routines.
1601 //===----------------------------------------------------------------------===//
1603 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1604 /// temporary label with the specified stem and unique ID.
1605 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1606 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1610 /// GetTempSymbol - Return an assembler temporary label with the specified
1612 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1613 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1618 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1619 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1622 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1623 return MMI->getAddrLabelSymbol(BB);
1626 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
1627 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1628 return OutContext.GetOrCreateSymbol
1629 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1630 + "_" + Twine(CPID));
1633 /// GetJTISymbol - Return the symbol for the specified jump table entry.
1634 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1635 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1638 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
1639 /// FIXME: privatize to AsmPrinter.
1640 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1641 return OutContext.GetOrCreateSymbol
1642 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1643 Twine(UID) + "_set_" + Twine(MBBID));
1646 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1647 /// global value name as its base, with the specified suffix, and where the
1648 /// symbol is forced to have private linkage if ForcePrivate is true.
1649 MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1651 bool ForcePrivate) const {
1652 SmallString<60> NameStr;
1653 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1654 NameStr.append(Suffix.begin(), Suffix.end());
1655 return OutContext.GetOrCreateSymbol(NameStr.str());
1658 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1660 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1661 SmallString<60> NameStr;
1662 Mang->getNameWithPrefix(NameStr, Sym);
1663 return OutContext.GetOrCreateSymbol(NameStr.str());
1668 /// PrintParentLoopComment - Print comments about parent loops of this one.
1669 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1670 unsigned FunctionNumber) {
1671 if (Loop == 0) return;
1672 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1673 OS.indent(Loop->getLoopDepth()*2)
1674 << "Parent Loop BB" << FunctionNumber << "_"
1675 << Loop->getHeader()->getNumber()
1676 << " Depth=" << Loop->getLoopDepth() << '\n';
1680 /// PrintChildLoopComment - Print comments about child loops within
1681 /// the loop for this basic block, with nesting.
1682 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1683 unsigned FunctionNumber) {
1684 // Add child loop information
1685 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1686 OS.indent((*CL)->getLoopDepth()*2)
1687 << "Child Loop BB" << FunctionNumber << "_"
1688 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1690 PrintChildLoopComment(OS, *CL, FunctionNumber);
1694 /// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1695 static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1696 const MachineLoopInfo *LI,
1697 const AsmPrinter &AP) {
1698 // Add loop depth information
1699 const MachineLoop *Loop = LI->getLoopFor(&MBB);
1700 if (Loop == 0) return;
1702 MachineBasicBlock *Header = Loop->getHeader();
1703 assert(Header && "No header for loop");
1705 // If this block is not a loop header, just print out what is the loop header
1707 if (Header != &MBB) {
1708 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
1709 Twine(AP.getFunctionNumber())+"_" +
1710 Twine(Loop->getHeader()->getNumber())+
1711 " Depth="+Twine(Loop->getLoopDepth()));
1715 // Otherwise, it is a loop header. Print out information about child and
1717 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1719 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1722 OS.indent(Loop->getLoopDepth()*2-2);
1727 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1729 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1733 /// EmitBasicBlockStart - This method prints the label for the specified
1734 /// MachineBasicBlock, an alignment (if present) and a comment describing
1735 /// it if appropriate.
1736 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1737 // Emit an alignment directive for this block, if needed.
1738 if (unsigned Align = MBB->getAlignment())
1739 EmitAlignment(Log2_32(Align));
1741 // If the block has its address taken, emit any labels that were used to
1742 // reference the block. It is possible that there is more than one label
1743 // here, because multiple LLVM BB's may have been RAUW'd to this block after
1744 // the references were generated.
1745 if (MBB->hasAddressTaken()) {
1746 const BasicBlock *BB = MBB->getBasicBlock();
1748 OutStreamer.AddComment("Block address taken");
1750 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1752 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1753 OutStreamer.EmitLabel(Syms[i]);
1756 // Print the main label for the block.
1757 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1758 if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1759 if (const BasicBlock *BB = MBB->getBasicBlock())
1761 OutStreamer.AddComment("%" + BB->getName());
1763 EmitBasicBlockLoopComments(*MBB, LI, *this);
1765 // NOTE: Want this comment at start of line, don't emit with AddComment.
1766 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1767 Twine(MBB->getNumber()) + ":");
1771 if (const BasicBlock *BB = MBB->getBasicBlock())
1773 OutStreamer.AddComment("%" + BB->getName());
1774 EmitBasicBlockLoopComments(*MBB, LI, *this);
1777 OutStreamer.EmitLabel(MBB->getSymbol());
1781 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1782 MCSymbolAttr Attr = MCSA_Invalid;
1784 switch (Visibility) {
1786 case GlobalValue::HiddenVisibility:
1787 Attr = MAI->getHiddenVisibilityAttr();
1789 case GlobalValue::ProtectedVisibility:
1790 Attr = MAI->getProtectedVisibilityAttr();
1794 if (Attr != MCSA_Invalid)
1795 OutStreamer.EmitSymbolAttribute(Sym, Attr);
1798 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
1799 /// exactly one predecessor and the control transfer mechanism between
1800 /// the predecessor and this block is a fall-through.
1802 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1803 // If this is a landing pad, it isn't a fall through. If it has no preds,
1804 // then nothing falls through to it.
1805 if (MBB->isLandingPad() || MBB->pred_empty())
1808 // If there isn't exactly one predecessor, it can't be a fall through.
1809 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1811 if (PI2 != MBB->pred_end())
1814 // The predecessor has to be immediately before this block.
1815 const MachineBasicBlock *Pred = *PI;
1817 if (!Pred->isLayoutSuccessor(MBB))
1820 // If the block is completely empty, then it definitely does fall through.
1824 // Otherwise, check the last instruction.
1825 const MachineInstr &LastInst = Pred->back();
1826 return !LastInst.getDesc().isBarrier();
1831 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1832 if (!S->usesMetadata())
1835 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1836 gcp_map_type::iterator GCPI = GCMap.find(S);
1837 if (GCPI != GCMap.end())
1838 return GCPI->second;
1840 const char *Name = S->getName().c_str();
1842 for (GCMetadataPrinterRegistry::iterator
1843 I = GCMetadataPrinterRegistry::begin(),
1844 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1845 if (strcmp(Name, I->getName()) == 0) {
1846 GCMetadataPrinter *GMP = I->instantiate();
1848 GCMap.insert(std::make_pair(S, GMP));
1852 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));