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(), 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 unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
514 if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
515 SrcSubIdx, DstSubIdx)) {
516 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
517 CommentOS << " Reload Reuse\n";
521 /// EmitImplicitDef - This method emits the specified machine instruction
522 /// that is an implicit def.
523 static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
524 unsigned RegNo = MI->getOperand(0).getReg();
525 AP.OutStreamer.AddComment(Twine("implicit-def: ") +
526 AP.TM.getRegisterInfo()->getName(RegNo));
527 AP.OutStreamer.AddBlankLine();
530 static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
531 std::string Str = "kill:";
532 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
533 const MachineOperand &Op = MI->getOperand(i);
534 assert(Op.isReg() && "KILL instruction must have only register operands");
536 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
537 Str += (Op.isDef() ? "<def>" : "<kill>");
539 AP.OutStreamer.AddComment(Str);
540 AP.OutStreamer.AddBlankLine();
543 /// EmitDebugValueComment - This method handles the target-independent form
544 /// of DBG_VALUE, returning true if it was able to do so. A false return
545 /// means the target will need to handle MI in EmitInstruction.
546 static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
547 // This code handles only the 3-operand target-independent form.
548 if (MI->getNumOperands() != 3)
551 SmallString<128> Str;
552 raw_svector_ostream OS(Str);
553 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
555 // cast away const; DIetc do not take const operands for some reason.
556 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
557 if (V.getContext().isSubprogram())
558 OS << DISubprogram(V.getContext()).getDisplayName() << ":";
559 OS << V.getName() << " <- ";
561 // Register or immediate value. Register 0 means undef.
562 if (MI->getOperand(0).isFPImm()) {
563 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
564 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
565 OS << (double)APF.convertToFloat();
566 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
567 OS << APF.convertToDouble();
569 // There is no good way to print long double. Convert a copy to
570 // double. Ah well, it's only a comment.
572 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
574 OS << "(long double) " << APF.convertToDouble();
576 } else if (MI->getOperand(0).isImm()) {
577 OS << MI->getOperand(0).getImm();
579 assert(MI->getOperand(0).isReg() && "Unknown operand type");
580 if (MI->getOperand(0).getReg() == 0) {
581 // Suppress offset, it is not meaningful here.
583 // NOTE: Want this comment at start of line, don't emit with AddComment.
584 AP.OutStreamer.EmitRawText(OS.str());
587 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
590 OS << '+' << MI->getOperand(1).getImm();
591 // NOTE: Want this comment at start of line, don't emit with AddComment.
592 AP.OutStreamer.EmitRawText(OS.str());
596 /// EmitFunctionBody - This method emits the body and trailer for a
598 void AsmPrinter::EmitFunctionBody() {
599 // Emit target-specific gunk before the function body.
600 EmitFunctionBodyStart();
602 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
604 // Print out code for the function.
605 bool HasAnyRealCode = false;
606 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
608 // Print a label for the basic block.
609 EmitBasicBlockStart(I);
610 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
612 // Print the assembly for the instruction.
613 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
614 !II->isDebugValue()) {
615 HasAnyRealCode = true;
619 if (ShouldPrintDebugScopes) {
620 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
625 EmitComments(*II, OutStreamer.GetCommentOS());
627 switch (II->getOpcode()) {
628 case TargetOpcode::DBG_LABEL:
629 case TargetOpcode::EH_LABEL:
630 case TargetOpcode::GC_LABEL:
631 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
633 case TargetOpcode::INLINEASM:
636 case TargetOpcode::DBG_VALUE:
638 if (!EmitDebugValueComment(II, *this))
642 case TargetOpcode::IMPLICIT_DEF:
643 if (isVerbose()) EmitImplicitDef(II, *this);
645 case TargetOpcode::KILL:
646 if (isVerbose()) EmitKill(II, *this);
653 if (ShouldPrintDebugScopes) {
654 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
660 // If the function is empty and the object file uses .subsections_via_symbols,
661 // then we need to emit *something* to the function body to prevent the
662 // labels from collapsing together. Just emit a noop.
663 if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) {
665 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
666 if (Noop.getOpcode()) {
667 OutStreamer.AddComment("avoids zero-length function");
668 OutStreamer.EmitInstruction(Noop);
669 } else // Target not mc-ized yet.
670 OutStreamer.EmitRawText(StringRef("\tnop\n"));
673 // Emit target-specific gunk after the function body.
674 EmitFunctionBodyEnd();
676 // If the target wants a .size directive for the size of the function, emit
678 if (MAI->hasDotTypeDotSizeDirective()) {
679 // Create a symbol for the end of function, so we can get the size as
680 // difference between the function label and the temp label.
681 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
682 OutStreamer.EmitLabel(FnEndLabel);
684 const MCExpr *SizeExp =
685 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
686 MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
688 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
691 // Emit post-function debug information.
693 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
697 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
702 // Print out jump tables referenced by the function.
705 OutStreamer.AddBlankLine();
708 /// getDebugValueLocation - Get location information encoded by DBG_VALUE
710 MachineLocation AsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
711 // Target specific DBG_VALUE instructions are handled by each target.
712 return MachineLocation();
715 bool AsmPrinter::doFinalization(Module &M) {
716 // Emit global variables.
717 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
719 EmitGlobalVariable(I);
721 // Finalize debug and EH information.
724 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
731 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
737 // If the target wants to know about weak references, print them all.
738 if (MAI->getWeakRefDirective()) {
739 // FIXME: This is not lazy, it would be nice to only print weak references
740 // to stuff that is actually used. Note that doing so would require targets
741 // to notice uses in operands (due to constant exprs etc). This should
742 // happen with the MC stuff eventually.
744 // Print out module-level global variables here.
745 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
747 if (!I->hasExternalWeakLinkage()) continue;
748 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
751 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
752 if (!I->hasExternalWeakLinkage()) continue;
753 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
757 if (MAI->hasSetDirective()) {
758 OutStreamer.AddBlankLine();
759 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
761 MCSymbol *Name = Mang->getSymbol(I);
763 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
764 MCSymbol *Target = Mang->getSymbol(GV);
766 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
767 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
768 else if (I->hasWeakLinkage())
769 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
771 assert(I->hasLocalLinkage() && "Invalid alias linkage");
773 EmitVisibility(Name, I->getVisibility());
775 // Emit the directives as assignments aka .set:
776 OutStreamer.EmitAssignment(Name,
777 MCSymbolRefExpr::Create(Target, OutContext));
781 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
782 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
783 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
784 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
785 MP->finishAssembly(*this);
787 // If we don't have any trampolines, then we don't require stack memory
788 // to be executable. Some targets have a directive to declare this.
789 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
790 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
791 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
792 OutStreamer.SwitchSection(S);
794 // Allow the target to emit any magic that it wants at the end of the file,
795 // after everything else has gone out.
798 delete Mang; Mang = 0;
801 OutStreamer.Finish();
805 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
807 // Get the function symbol.
808 CurrentFnSym = Mang->getSymbol(MF.getFunction());
811 LI = &getAnalysis<MachineLoopInfo>();
815 // SectionCPs - Keep track the alignment, constpool entries per Section.
819 SmallVector<unsigned, 4> CPEs;
820 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
824 /// EmitConstantPool - Print to the current output stream assembly
825 /// representations of the constants in the constant pool MCP. This is
826 /// used to print out constants which have been "spilled to memory" by
827 /// the code generator.
829 void AsmPrinter::EmitConstantPool() {
830 const MachineConstantPool *MCP = MF->getConstantPool();
831 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
832 if (CP.empty()) return;
834 // Calculate sections for constant pool entries. We collect entries to go into
835 // the same section together to reduce amount of section switch statements.
836 SmallVector<SectionCPs, 4> CPSections;
837 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
838 const MachineConstantPoolEntry &CPE = CP[i];
839 unsigned Align = CPE.getAlignment();
842 switch (CPE.getRelocationInfo()) {
843 default: llvm_unreachable("Unknown section kind");
844 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
846 Kind = SectionKind::getReadOnlyWithRelLocal();
849 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
850 case 4: Kind = SectionKind::getMergeableConst4(); break;
851 case 8: Kind = SectionKind::getMergeableConst8(); break;
852 case 16: Kind = SectionKind::getMergeableConst16();break;
853 default: Kind = SectionKind::getMergeableConst(); break;
857 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
859 // The number of sections are small, just do a linear search from the
860 // last section to the first.
862 unsigned SecIdx = CPSections.size();
863 while (SecIdx != 0) {
864 if (CPSections[--SecIdx].S == S) {
870 SecIdx = CPSections.size();
871 CPSections.push_back(SectionCPs(S, Align));
874 if (Align > CPSections[SecIdx].Alignment)
875 CPSections[SecIdx].Alignment = Align;
876 CPSections[SecIdx].CPEs.push_back(i);
879 // Now print stuff into the calculated sections.
880 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
881 OutStreamer.SwitchSection(CPSections[i].S);
882 EmitAlignment(Log2_32(CPSections[i].Alignment));
885 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
886 unsigned CPI = CPSections[i].CPEs[j];
887 MachineConstantPoolEntry CPE = CP[CPI];
889 // Emit inter-object padding for alignment.
890 unsigned AlignMask = CPE.getAlignment() - 1;
891 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
892 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
894 const Type *Ty = CPE.getType();
895 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
897 // Emit the label with a comment on it.
899 OutStreamer.GetCommentOS() << "constant pool ";
900 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
901 MF->getFunction()->getParent());
902 OutStreamer.GetCommentOS() << '\n';
904 OutStreamer.EmitLabel(GetCPISymbol(CPI));
906 if (CPE.isMachineConstantPoolEntry())
907 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
909 EmitGlobalConstant(CPE.Val.ConstVal);
914 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
915 /// by the current function to the current output stream.
917 void AsmPrinter::EmitJumpTableInfo() {
918 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
919 if (MJTI == 0) return;
920 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
921 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
922 if (JT.empty()) return;
924 // Pick the directive to use to print the jump table entries, and switch to
925 // the appropriate section.
926 const Function *F = MF->getFunction();
927 bool JTInDiffSection = false;
928 if (// In PIC mode, we need to emit the jump table to the same section as the
929 // function body itself, otherwise the label differences won't make sense.
930 // FIXME: Need a better predicate for this: what about custom entries?
931 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
932 // We should also do if the section name is NULL or function is declared
933 // in discardable section
934 // FIXME: this isn't the right predicate, should be based on the MCSection
936 F->isWeakForLinker()) {
937 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
939 // Otherwise, drop it in the readonly section.
940 const MCSection *ReadOnlySection =
941 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
942 OutStreamer.SwitchSection(ReadOnlySection);
943 JTInDiffSection = true;
946 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
948 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
949 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
951 // If this jump table was deleted, ignore it.
952 if (JTBBs.empty()) continue;
954 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
955 // .set directive for each unique entry. This reduces the number of
956 // relocations the assembler will generate for the jump table.
957 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
958 MAI->hasSetDirective()) {
959 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
960 const TargetLowering *TLI = TM.getTargetLowering();
961 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
962 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
963 const MachineBasicBlock *MBB = JTBBs[ii];
964 if (!EmittedSets.insert(MBB)) continue;
966 // .set LJTSet, LBB32-base
968 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
969 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
970 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
974 // On some targets (e.g. Darwin) we want to emit two consequtive labels
975 // before each jump table. The first label is never referenced, but tells
976 // the assembler and linker the extents of the jump table object. The
977 // second label is actually referenced by the code.
978 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
979 // FIXME: This doesn't have to have any specific name, just any randomly
980 // named and numbered 'l' label would work. Simplify GetJTISymbol.
981 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
983 OutStreamer.EmitLabel(GetJTISymbol(JTI));
985 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
986 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
990 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
992 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
993 const MachineBasicBlock *MBB,
994 unsigned UID) const {
995 const MCExpr *Value = 0;
996 switch (MJTI->getEntryKind()) {
997 case MachineJumpTableInfo::EK_Inline:
998 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
999 case MachineJumpTableInfo::EK_Custom32:
1000 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1003 case MachineJumpTableInfo::EK_BlockAddress:
1004 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1006 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1008 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1009 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1010 // with a relocation as gp-relative, e.g.:
1012 MCSymbol *MBBSym = MBB->getSymbol();
1013 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1017 case MachineJumpTableInfo::EK_LabelDifference32: {
1018 // EK_LabelDifference32 - Each entry is the address of the block minus
1019 // the address of the jump table. This is used for PIC jump tables where
1020 // gprel32 is not supported. e.g.:
1021 // .word LBB123 - LJTI1_2
1022 // If the .set directive is supported, this is emitted as:
1023 // .set L4_5_set_123, LBB123 - LJTI1_2
1024 // .word L4_5_set_123
1026 // If we have emitted set directives for the jump table entries, print
1027 // them rather than the entries themselves. If we're emitting PIC, then
1028 // emit the table entries as differences between two text section labels.
1029 if (MAI->hasSetDirective()) {
1030 // If we used .set, reference the .set's symbol.
1031 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1035 // Otherwise, use the difference as the jump table entry.
1036 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1037 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1038 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1043 assert(Value && "Unknown entry kind!");
1045 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
1046 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
1050 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1051 /// special global used by LLVM. If so, emit it and return true, otherwise
1052 /// do nothing and return false.
1053 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1054 if (GV->getName() == "llvm.used") {
1055 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1056 EmitLLVMUsedList(GV->getInitializer());
1060 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1061 if (GV->getSection() == "llvm.metadata" ||
1062 GV->hasAvailableExternallyLinkage())
1065 if (!GV->hasAppendingLinkage()) return false;
1067 assert(GV->hasInitializer() && "Not a special LLVM global!");
1069 const TargetData *TD = TM.getTargetData();
1070 unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1071 if (GV->getName() == "llvm.global_ctors") {
1072 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1073 EmitAlignment(Align);
1074 EmitXXStructorList(GV->getInitializer());
1076 if (TM.getRelocationModel() == Reloc::Static &&
1077 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1078 StringRef Sym(".constructors_used");
1079 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1085 if (GV->getName() == "llvm.global_dtors") {
1086 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1087 EmitAlignment(Align);
1088 EmitXXStructorList(GV->getInitializer());
1090 if (TM.getRelocationModel() == Reloc::Static &&
1091 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1092 StringRef Sym(".destructors_used");
1093 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1102 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1103 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1104 /// is true, as being used with this directive.
1105 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1106 // Should be an array of 'i8*'.
1107 ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1108 if (InitList == 0) return;
1110 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1111 const GlobalValue *GV =
1112 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1113 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1114 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1118 /// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
1119 /// function pointers, ignoring the init priority.
1120 void AsmPrinter::EmitXXStructorList(Constant *List) {
1121 // Should be an array of '{ int, void ()* }' structs. The first value is the
1122 // init priority, which we ignore.
1123 if (!isa<ConstantArray>(List)) return;
1124 ConstantArray *InitList = cast<ConstantArray>(List);
1125 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1126 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1127 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
1129 if (CS->getOperand(1)->isNullValue())
1130 return; // Found a null terminator, exit printing.
1131 // Emit the function pointer.
1132 EmitGlobalConstant(CS->getOperand(1));
1136 //===--------------------------------------------------------------------===//
1137 // Emission and print routines
1140 /// EmitInt8 - Emit a byte directive and value.
1142 void AsmPrinter::EmitInt8(int Value) const {
1143 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1146 /// EmitInt16 - Emit a short directive and value.
1148 void AsmPrinter::EmitInt16(int Value) const {
1149 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1152 /// EmitInt32 - Emit a long directive and value.
1154 void AsmPrinter::EmitInt32(int Value) const {
1155 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1158 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1159 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1160 /// labels. This implicitly uses .set if it is available.
1161 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1162 unsigned Size) const {
1163 // Get the Hi-Lo expression.
1164 const MCExpr *Diff =
1165 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1166 MCSymbolRefExpr::Create(Lo, OutContext),
1169 if (!MAI->hasSetDirective()) {
1170 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1174 // Otherwise, emit with .set (aka assignment).
1175 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1176 OutStreamer.EmitAssignment(SetLabel, Diff);
1177 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1180 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1181 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1182 /// specify the labels. This implicitly uses .set if it is available.
1183 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1184 const MCSymbol *Lo, unsigned Size)
1187 // Emit Hi+Offset - Lo
1188 // Get the Hi+Offset expression.
1189 const MCExpr *Plus =
1190 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1191 MCConstantExpr::Create(Offset, OutContext),
1194 // Get the Hi+Offset-Lo expression.
1195 const MCExpr *Diff =
1196 MCBinaryExpr::CreateSub(Plus,
1197 MCSymbolRefExpr::Create(Lo, OutContext),
1200 if (!MAI->hasSetDirective())
1201 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1203 // Otherwise, emit with .set (aka assignment).
1204 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1205 OutStreamer.EmitAssignment(SetLabel, Diff);
1206 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1211 //===----------------------------------------------------------------------===//
1213 // EmitAlignment - Emit an alignment directive to the specified power of
1214 // two boundary. For example, if you pass in 3 here, you will get an 8
1215 // byte alignment. If a global value is specified, and if that global has
1216 // an explicit alignment requested, it will override the alignment request
1217 // if required for correctness.
1219 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1220 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
1222 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1224 if (getCurrentSection()->getKind().isText())
1225 OutStreamer.EmitCodeAlignment(1 << NumBits);
1227 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1230 //===----------------------------------------------------------------------===//
1231 // Constant emission.
1232 //===----------------------------------------------------------------------===//
1234 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1236 static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1237 MCContext &Ctx = AP.OutContext;
1239 if (CV->isNullValue() || isa<UndefValue>(CV))
1240 return MCConstantExpr::Create(0, Ctx);
1242 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1243 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1245 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1246 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1247 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1248 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1250 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1252 llvm_unreachable("Unknown constant value to lower!");
1253 return MCConstantExpr::Create(0, Ctx);
1256 switch (CE->getOpcode()) {
1258 // If the code isn't optimized, there may be outstanding folding
1259 // opportunities. Attempt to fold the expression using TargetData as a
1260 // last resort before giving up.
1262 ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1264 return LowerConstant(C, AP);
1268 llvm_unreachable("FIXME: Don't support this constant expr");
1269 case Instruction::GetElementPtr: {
1270 const TargetData &TD = *AP.TM.getTargetData();
1271 // Generate a symbolic expression for the byte address
1272 const Constant *PtrVal = CE->getOperand(0);
1273 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1274 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1277 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1281 // Truncate/sext the offset to the pointer size.
1282 if (TD.getPointerSizeInBits() != 64) {
1283 int SExtAmount = 64-TD.getPointerSizeInBits();
1284 Offset = (Offset << SExtAmount) >> SExtAmount;
1287 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1291 case Instruction::Trunc:
1292 // We emit the value and depend on the assembler to truncate the generated
1293 // expression properly. This is important for differences between
1294 // blockaddress labels. Since the two labels are in the same function, it
1295 // is reasonable to treat their delta as a 32-bit value.
1297 case Instruction::BitCast:
1298 return LowerConstant(CE->getOperand(0), AP);
1300 case Instruction::IntToPtr: {
1301 const TargetData &TD = *AP.TM.getTargetData();
1302 // Handle casts to pointers by changing them into casts to the appropriate
1303 // integer type. This promotes constant folding and simplifies this code.
1304 Constant *Op = CE->getOperand(0);
1305 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1307 return LowerConstant(Op, AP);
1310 case Instruction::PtrToInt: {
1311 const TargetData &TD = *AP.TM.getTargetData();
1312 // Support only foldable casts to/from pointers that can be eliminated by
1313 // changing the pointer to the appropriately sized integer type.
1314 Constant *Op = CE->getOperand(0);
1315 const Type *Ty = CE->getType();
1317 const MCExpr *OpExpr = LowerConstant(Op, AP);
1319 // We can emit the pointer value into this slot if the slot is an
1320 // integer slot equal to the size of the pointer.
1321 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1324 // Otherwise the pointer is smaller than the resultant integer, mask off
1325 // the high bits so we are sure to get a proper truncation if the input is
1327 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1328 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1329 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1332 // The MC library also has a right-shift operator, but it isn't consistently
1333 // signed or unsigned between different targets.
1334 case Instruction::Add:
1335 case Instruction::Sub:
1336 case Instruction::Mul:
1337 case Instruction::SDiv:
1338 case Instruction::SRem:
1339 case Instruction::Shl:
1340 case Instruction::And:
1341 case Instruction::Or:
1342 case Instruction::Xor: {
1343 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1344 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1345 switch (CE->getOpcode()) {
1346 default: llvm_unreachable("Unknown binary operator constant cast expr");
1347 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1348 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1349 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1350 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1351 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1352 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1353 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1354 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1355 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1361 static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1364 static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1366 if (AddrSpace != 0 || !CA->isString()) {
1367 // Not a string. Print the values in successive locations
1368 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1369 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1373 // Otherwise, it can be emitted as .ascii.
1374 SmallVector<char, 128> TmpVec;
1375 TmpVec.reserve(CA->getNumOperands());
1376 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1377 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1379 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1382 static void EmitGlobalConstantVector(const ConstantVector *CV,
1383 unsigned AddrSpace, AsmPrinter &AP) {
1384 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1385 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1388 static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1389 unsigned AddrSpace, AsmPrinter &AP) {
1390 // Print the fields in successive locations. Pad to align if needed!
1391 const TargetData *TD = AP.TM.getTargetData();
1392 unsigned Size = TD->getTypeAllocSize(CS->getType());
1393 const StructLayout *Layout = TD->getStructLayout(CS->getType());
1394 uint64_t SizeSoFar = 0;
1395 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1396 const Constant *Field = CS->getOperand(i);
1398 // Check if padding is needed and insert one or more 0s.
1399 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1400 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1401 - Layout->getElementOffset(i)) - FieldSize;
1402 SizeSoFar += FieldSize + PadSize;
1404 // Now print the actual field value.
1405 EmitGlobalConstantImpl(Field, AddrSpace, AP);
1407 // Insert padding - this may include padding to increase the size of the
1408 // current field up to the ABI size (if the struct is not packed) as well
1409 // as padding to ensure that the next field starts at the right offset.
1410 AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1412 assert(SizeSoFar == Layout->getSizeInBytes() &&
1413 "Layout of constant struct may be incorrect!");
1416 static void EmitGlobalConstantUnion(const ConstantUnion *CU,
1417 unsigned AddrSpace, AsmPrinter &AP) {
1418 const TargetData *TD = AP.TM.getTargetData();
1419 unsigned Size = TD->getTypeAllocSize(CU->getType());
1421 const Constant *Contents = CU->getOperand(0);
1422 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType());
1424 // Print the actually filled part
1425 EmitGlobalConstantImpl(Contents, AddrSpace, AP);
1427 // And pad with enough zeroes
1428 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace);
1431 static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1433 // FP Constants are printed as integer constants to avoid losing
1435 if (CFP->getType()->isDoubleTy()) {
1436 if (AP.isVerbose()) {
1437 double Val = CFP->getValueAPF().convertToDouble();
1438 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1441 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1442 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1446 if (CFP->getType()->isFloatTy()) {
1447 if (AP.isVerbose()) {
1448 float Val = CFP->getValueAPF().convertToFloat();
1449 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1451 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1452 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1456 if (CFP->getType()->isX86_FP80Ty()) {
1457 // all long double variants are printed as hex
1458 // API needed to prevent premature destruction
1459 APInt API = CFP->getValueAPF().bitcastToAPInt();
1460 const uint64_t *p = API.getRawData();
1461 if (AP.isVerbose()) {
1462 // Convert to double so we can print the approximate val as a comment.
1463 APFloat DoubleVal = CFP->getValueAPF();
1465 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1467 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1468 << DoubleVal.convertToDouble() << '\n';
1471 if (AP.TM.getTargetData()->isBigEndian()) {
1472 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1473 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1475 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1476 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1479 // Emit the tail padding for the long double.
1480 const TargetData &TD = *AP.TM.getTargetData();
1481 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1482 TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1486 assert(CFP->getType()->isPPC_FP128Ty() &&
1487 "Floating point constant type not handled");
1488 // All long double variants are printed as hex
1489 // API needed to prevent premature destruction.
1490 APInt API = CFP->getValueAPF().bitcastToAPInt();
1491 const uint64_t *p = API.getRawData();
1492 if (AP.TM.getTargetData()->isBigEndian()) {
1493 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1494 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1496 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1497 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1501 static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1502 unsigned AddrSpace, AsmPrinter &AP) {
1503 const TargetData *TD = AP.TM.getTargetData();
1504 unsigned BitWidth = CI->getBitWidth();
1505 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1507 // We don't expect assemblers to support integer data directives
1508 // for more than 64 bits, so we emit the data in at most 64-bit
1509 // quantities at a time.
1510 const uint64_t *RawData = CI->getValue().getRawData();
1511 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1512 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1513 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1517 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1519 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1520 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1521 return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1524 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1525 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1532 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1533 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1536 EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1541 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1542 return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1544 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1545 return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1547 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1548 return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1550 if (isa<ConstantPointerNull>(CV)) {
1551 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1552 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1556 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV))
1557 return EmitGlobalConstantUnion(CVU, AddrSpace, AP);
1559 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1560 return EmitGlobalConstantVector(V, AddrSpace, AP);
1562 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
1563 // thread the streamer with EmitValue.
1564 AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1565 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1569 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1570 void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1571 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1573 EmitGlobalConstantImpl(CV, AddrSpace, *this);
1574 else if (MAI->hasSubsectionsViaSymbols()) {
1575 // If the global has zero size, emit a single byte so that two labels don't
1576 // look like they are at the same location.
1577 OutStreamer.EmitIntValue(0, 1, AddrSpace);
1581 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1582 // Target doesn't support this yet!
1583 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1586 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1588 OS << '+' << Offset;
1589 else if (Offset < 0)
1593 //===----------------------------------------------------------------------===//
1594 // Symbol Lowering Routines.
1595 //===----------------------------------------------------------------------===//
1597 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1598 /// temporary label with the specified stem and unique ID.
1599 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1600 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1604 /// GetTempSymbol - Return an assembler temporary label with the specified
1606 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1607 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1612 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1613 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1616 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1617 return MMI->getAddrLabelSymbol(BB);
1620 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
1621 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1622 return OutContext.GetOrCreateSymbol
1623 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1624 + "_" + Twine(CPID));
1627 /// GetJTISymbol - Return the symbol for the specified jump table entry.
1628 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1629 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1632 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
1633 /// FIXME: privatize to AsmPrinter.
1634 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1635 return OutContext.GetOrCreateSymbol
1636 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1637 Twine(UID) + "_set_" + Twine(MBBID));
1640 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1641 /// global value name as its base, with the specified suffix, and where the
1642 /// symbol is forced to have private linkage if ForcePrivate is true.
1643 MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1645 bool ForcePrivate) const {
1646 SmallString<60> NameStr;
1647 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1648 NameStr.append(Suffix.begin(), Suffix.end());
1649 return OutContext.GetOrCreateSymbol(NameStr.str());
1652 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1654 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1655 SmallString<60> NameStr;
1656 Mang->getNameWithPrefix(NameStr, Sym);
1657 return OutContext.GetOrCreateSymbol(NameStr.str());
1662 /// PrintParentLoopComment - Print comments about parent loops of this one.
1663 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1664 unsigned FunctionNumber) {
1665 if (Loop == 0) return;
1666 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1667 OS.indent(Loop->getLoopDepth()*2)
1668 << "Parent Loop BB" << FunctionNumber << "_"
1669 << Loop->getHeader()->getNumber()
1670 << " Depth=" << Loop->getLoopDepth() << '\n';
1674 /// PrintChildLoopComment - Print comments about child loops within
1675 /// the loop for this basic block, with nesting.
1676 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1677 unsigned FunctionNumber) {
1678 // Add child loop information
1679 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1680 OS.indent((*CL)->getLoopDepth()*2)
1681 << "Child Loop BB" << FunctionNumber << "_"
1682 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1684 PrintChildLoopComment(OS, *CL, FunctionNumber);
1688 /// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1689 static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1690 const MachineLoopInfo *LI,
1691 const AsmPrinter &AP) {
1692 // Add loop depth information
1693 const MachineLoop *Loop = LI->getLoopFor(&MBB);
1694 if (Loop == 0) return;
1696 MachineBasicBlock *Header = Loop->getHeader();
1697 assert(Header && "No header for loop");
1699 // If this block is not a loop header, just print out what is the loop header
1701 if (Header != &MBB) {
1702 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
1703 Twine(AP.getFunctionNumber())+"_" +
1704 Twine(Loop->getHeader()->getNumber())+
1705 " Depth="+Twine(Loop->getLoopDepth()));
1709 // Otherwise, it is a loop header. Print out information about child and
1711 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1713 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1716 OS.indent(Loop->getLoopDepth()*2-2);
1721 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1723 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1727 /// EmitBasicBlockStart - This method prints the label for the specified
1728 /// MachineBasicBlock, an alignment (if present) and a comment describing
1729 /// it if appropriate.
1730 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1731 // Emit an alignment directive for this block, if needed.
1732 if (unsigned Align = MBB->getAlignment())
1733 EmitAlignment(Log2_32(Align));
1735 // If the block has its address taken, emit any labels that were used to
1736 // reference the block. It is possible that there is more than one label
1737 // here, because multiple LLVM BB's may have been RAUW'd to this block after
1738 // the references were generated.
1739 if (MBB->hasAddressTaken()) {
1740 const BasicBlock *BB = MBB->getBasicBlock();
1742 OutStreamer.AddComment("Block address taken");
1744 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1746 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1747 OutStreamer.EmitLabel(Syms[i]);
1750 // Print the main label for the block.
1751 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1752 if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1753 if (const BasicBlock *BB = MBB->getBasicBlock())
1755 OutStreamer.AddComment("%" + BB->getName());
1757 EmitBasicBlockLoopComments(*MBB, LI, *this);
1759 // NOTE: Want this comment at start of line, don't emit with AddComment.
1760 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1761 Twine(MBB->getNumber()) + ":");
1765 if (const BasicBlock *BB = MBB->getBasicBlock())
1767 OutStreamer.AddComment("%" + BB->getName());
1768 EmitBasicBlockLoopComments(*MBB, LI, *this);
1771 OutStreamer.EmitLabel(MBB->getSymbol());
1775 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1776 MCSymbolAttr Attr = MCSA_Invalid;
1778 switch (Visibility) {
1780 case GlobalValue::HiddenVisibility:
1781 Attr = MAI->getHiddenVisibilityAttr();
1783 case GlobalValue::ProtectedVisibility:
1784 Attr = MAI->getProtectedVisibilityAttr();
1788 if (Attr != MCSA_Invalid)
1789 OutStreamer.EmitSymbolAttribute(Sym, Attr);
1792 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
1793 /// exactly one predecessor and the control transfer mechanism between
1794 /// the predecessor and this block is a fall-through.
1796 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1797 // If this is a landing pad, it isn't a fall through. If it has no preds,
1798 // then nothing falls through to it.
1799 if (MBB->isLandingPad() || MBB->pred_empty())
1802 // If there isn't exactly one predecessor, it can't be a fall through.
1803 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1805 if (PI2 != MBB->pred_end())
1808 // The predecessor has to be immediately before this block.
1809 const MachineBasicBlock *Pred = *PI;
1811 if (!Pred->isLayoutSuccessor(MBB))
1814 // If the block is completely empty, then it definitely does fall through.
1818 // Otherwise, check the last instruction.
1819 const MachineInstr &LastInst = Pred->back();
1820 return !LastInst.getDesc().isBarrier();
1825 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1826 if (!S->usesMetadata())
1829 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1830 gcp_map_type::iterator GCPI = GCMap.find(S);
1831 if (GCPI != GCMap.end())
1832 return GCPI->second;
1834 const char *Name = S->getName().c_str();
1836 for (GCMetadataPrinterRegistry::iterator
1837 I = GCMetadataPrinterRegistry::begin(),
1838 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1839 if (strcmp(Name, I->getName()) == 0) {
1840 GCMetadataPrinter *GMP = I->instantiate();
1842 GCMap.insert(std::make_pair(S, GMP));
1846 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));