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 case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
204 if (MAI->getWeakDefDirective() != 0) {
206 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
208 if ((GlobalValue::LinkageTypes)Linkage !=
209 GlobalValue::LinkerPrivateWeakDefAutoLinkage)
210 // .weak_definition _foo
211 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
213 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
214 } else if (MAI->getLinkOnceDirective() != 0) {
216 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
217 //NOTE: linkonce is handled by the section the symbol was assigned to.
220 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
223 case GlobalValue::DLLExportLinkage:
224 case GlobalValue::AppendingLinkage:
225 // FIXME: appending linkage variables should go into a section of
226 // their name or something. For now, just emit them as external.
227 case GlobalValue::ExternalLinkage:
228 // If external or appending, declare as a global symbol.
230 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
232 case GlobalValue::PrivateLinkage:
233 case GlobalValue::InternalLinkage:
234 case GlobalValue::LinkerPrivateLinkage:
237 llvm_unreachable("Unknown linkage type!");
242 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
243 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
244 if (!GV->hasInitializer()) // External globals require no code.
247 // Check to see if this is a special global used by LLVM, if so, emit it.
248 if (EmitSpecialLLVMGlobal(GV))
252 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
253 /*PrintType=*/false, GV->getParent());
254 OutStreamer.GetCommentOS() << '\n';
257 MCSymbol *GVSym = Mang->getSymbol(GV);
258 EmitVisibility(GVSym, GV->getVisibility());
260 if (MAI->hasDotTypeDotSizeDirective())
261 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
263 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
265 const TargetData *TD = TM.getTargetData();
266 uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());
268 // If the alignment is specified, we *must* obey it. Overaligning a global
269 // with a specified alignment is a prompt way to break globals emitted to
270 // sections and expected to be contiguous (e.g. ObjC metadata).
271 unsigned AlignLog = getGVAlignmentLog2(GV, *TD);
273 // Handle common and BSS local symbols (.lcomm).
274 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
275 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
278 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
279 /*PrintType=*/false, GV->getParent());
280 OutStreamer.GetCommentOS() << '\n';
283 // Handle common symbols.
284 if (GVKind.isCommon()) {
286 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
290 // Handle local BSS symbols.
291 if (MAI->hasMachoZeroFillDirective()) {
292 const MCSection *TheSection =
293 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
294 // .zerofill __DATA, __bss, _foo, 400, 5
295 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
299 if (MAI->hasLCOMMDirective()) {
301 OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
306 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
308 OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
312 const MCSection *TheSection =
313 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
315 // Handle the zerofill directive on darwin, which is a special form of BSS
317 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
318 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
321 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
322 // .zerofill __DATA, __common, _foo, 400, 5
323 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
327 // Handle thread local data for mach-o which requires us to output an
328 // additional structure of data and mangle the original symbol so that we
329 // can reference it later.
330 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
331 // Emit the .tbss symbol
333 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
335 if (GVKind.isThreadBSS())
336 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
337 else if (GVKind.isThreadData()) {
338 OutStreamer.SwitchSection(TheSection);
340 EmitAlignment(AlignLog, GV);
341 OutStreamer.EmitLabel(MangSym);
343 EmitGlobalConstant(GV->getInitializer());
346 OutStreamer.AddBlankLine();
348 // Emit the variable struct for the runtime.
349 const MCSection *TLVSect
350 = getObjFileLowering().getTLSExtraDataSection();
352 OutStreamer.SwitchSection(TLVSect);
353 // Emit the linkage here.
354 EmitLinkage(GV->getLinkage(), GVSym);
355 OutStreamer.EmitLabel(GVSym);
357 // Three pointers in size:
358 // - __tlv_bootstrap - used to make sure support exists
359 // - spare pointer, used when mapped by the runtime
360 // - pointer to mangled symbol above with initializer
361 unsigned PtrSize = TD->getPointerSizeInBits()/8;
362 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
364 OutStreamer.EmitIntValue(0, PtrSize, 0);
365 OutStreamer.EmitSymbolValue(MangSym, PtrSize, 0);
367 OutStreamer.AddBlankLine();
371 OutStreamer.SwitchSection(TheSection);
373 EmitLinkage(GV->getLinkage(), GVSym);
374 EmitAlignment(AlignLog, GV);
376 OutStreamer.EmitLabel(GVSym);
378 EmitGlobalConstant(GV->getInitializer());
380 if (MAI->hasDotTypeDotSizeDirective())
382 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
384 OutStreamer.AddBlankLine();
387 /// EmitFunctionHeader - This method emits the header for the current
389 void AsmPrinter::EmitFunctionHeader() {
390 // Print out constants referenced by the function
393 // Print the 'header' of function.
394 const Function *F = MF->getFunction();
396 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
397 EmitVisibility(CurrentFnSym, F->getVisibility());
399 EmitLinkage(F->getLinkage(), CurrentFnSym);
400 EmitAlignment(MF->getAlignment(), F);
402 if (MAI->hasDotTypeDotSizeDirective())
403 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
406 WriteAsOperand(OutStreamer.GetCommentOS(), F,
407 /*PrintType=*/false, F->getParent());
408 OutStreamer.GetCommentOS() << '\n';
411 // Emit the CurrentFnSym. This is a virtual function to allow targets to
412 // do their wild and crazy things as required.
413 EmitFunctionEntryLabel();
415 // If the function had address-taken blocks that got deleted, then we have
416 // references to the dangling symbols. Emit them at the start of the function
417 // so that we don't get references to undefined symbols.
418 std::vector<MCSymbol*> DeadBlockSyms;
419 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
420 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
421 OutStreamer.AddComment("Address taken block that was later removed");
422 OutStreamer.EmitLabel(DeadBlockSyms[i]);
425 // Add some workaround for linkonce linkage on Cygwin\MinGW.
426 if (MAI->getLinkOnceDirective() != 0 &&
427 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
428 // FIXME: What is this?
430 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
431 CurrentFnSym->getName());
432 OutStreamer.EmitLabel(FakeStub);
435 // Emit pre-function debug and/or EH information.
437 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
438 DE->BeginFunction(MF);
441 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
442 DD->beginFunction(MF);
446 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
447 /// function. This can be overridden by targets as required to do custom stuff.
448 void AsmPrinter::EmitFunctionEntryLabel() {
449 // The function label could have already been emitted if two symbols end up
450 // conflicting due to asm renaming. Detect this and emit an error.
451 if (CurrentFnSym->isUndefined())
452 return OutStreamer.EmitLabel(CurrentFnSym);
454 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
455 "' label emitted multiple times to assembly file");
459 static void EmitDebugLoc(DebugLoc DL, const MachineFunction *MF,
460 raw_ostream &CommentOS) {
461 const LLVMContext &Ctx = MF->getFunction()->getContext();
462 if (!DL.isUnknown()) { // Print source line info.
463 DIScope Scope(DL.getScope(Ctx));
464 // Omit the directory, because it's likely to be long and uninteresting.
466 CommentOS << Scope.getFilename();
468 CommentOS << "<unknown>";
469 CommentOS << ':' << DL.getLine();
470 if (DL.getCol() != 0)
471 CommentOS << ':' << DL.getCol();
472 DebugLoc InlinedAtDL = DebugLoc::getFromDILocation(DL.getInlinedAt(Ctx));
473 if (!InlinedAtDL.isUnknown()) {
475 EmitDebugLoc(InlinedAtDL, MF, CommentOS);
481 /// EmitComments - Pretty-print comments for instructions.
482 static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
483 const MachineFunction *MF = MI.getParent()->getParent();
484 const TargetMachine &TM = MF->getTarget();
486 DebugLoc DL = MI.getDebugLoc();
487 if (!DL.isUnknown()) { // Print source line info.
488 EmitDebugLoc(DL, MF, CommentOS);
492 // Check for spills and reloads
495 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
497 // We assume a single instruction only has a spill or reload, not
499 const MachineMemOperand *MMO;
500 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
501 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
502 MMO = *MI.memoperands_begin();
503 CommentOS << MMO->getSize() << "-byte Reload\n";
505 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
506 if (FrameInfo->isSpillSlotObjectIndex(FI))
507 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
508 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
509 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
510 MMO = *MI.memoperands_begin();
511 CommentOS << MMO->getSize() << "-byte Spill\n";
513 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
514 if (FrameInfo->isSpillSlotObjectIndex(FI))
515 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
518 // Check for spill-induced copies
519 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
520 CommentOS << " Reload Reuse\n";
523 /// EmitImplicitDef - This method emits the specified machine instruction
524 /// that is an implicit def.
525 static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
526 unsigned RegNo = MI->getOperand(0).getReg();
527 AP.OutStreamer.AddComment(Twine("implicit-def: ") +
528 AP.TM.getRegisterInfo()->getName(RegNo));
529 AP.OutStreamer.AddBlankLine();
532 static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
533 std::string Str = "kill:";
534 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
535 const MachineOperand &Op = MI->getOperand(i);
536 assert(Op.isReg() && "KILL instruction must have only register operands");
538 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
539 Str += (Op.isDef() ? "<def>" : "<kill>");
541 AP.OutStreamer.AddComment(Str);
542 AP.OutStreamer.AddBlankLine();
545 /// EmitDebugValueComment - This method handles the target-independent form
546 /// of DBG_VALUE, returning true if it was able to do so. A false return
547 /// means the target will need to handle MI in EmitInstruction.
548 static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
549 // This code handles only the 3-operand target-independent form.
550 if (MI->getNumOperands() != 3)
553 SmallString<128> Str;
554 raw_svector_ostream OS(Str);
555 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
557 // cast away const; DIetc do not take const operands for some reason.
558 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
559 if (V.getContext().isSubprogram())
560 OS << DISubprogram(V.getContext()).getDisplayName() << ":";
561 OS << V.getName() << " <- ";
563 // Register or immediate value. Register 0 means undef.
564 if (MI->getOperand(0).isFPImm()) {
565 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
566 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
567 OS << (double)APF.convertToFloat();
568 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
569 OS << APF.convertToDouble();
571 // There is no good way to print long double. Convert a copy to
572 // double. Ah well, it's only a comment.
574 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
576 OS << "(long double) " << APF.convertToDouble();
578 } else if (MI->getOperand(0).isImm()) {
579 OS << MI->getOperand(0).getImm();
581 assert(MI->getOperand(0).isReg() && "Unknown operand type");
582 if (MI->getOperand(0).getReg() == 0) {
583 // Suppress offset, it is not meaningful here.
585 // NOTE: Want this comment at start of line, don't emit with AddComment.
586 AP.OutStreamer.EmitRawText(OS.str());
589 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
592 OS << '+' << MI->getOperand(1).getImm();
593 // NOTE: Want this comment at start of line, don't emit with AddComment.
594 AP.OutStreamer.EmitRawText(OS.str());
598 /// EmitFunctionBody - This method emits the body and trailer for a
600 void AsmPrinter::EmitFunctionBody() {
601 // Emit target-specific gunk before the function body.
602 EmitFunctionBodyStart();
604 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
606 // Print out code for the function.
607 bool HasAnyRealCode = false;
608 const MachineInstr *LastMI = 0;
609 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
611 // Print a label for the basic block.
612 EmitBasicBlockStart(I);
613 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
617 // Print the assembly for the instruction.
618 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
619 !II->isDebugValue()) {
620 HasAnyRealCode = true;
624 if (ShouldPrintDebugScopes) {
625 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
630 EmitComments(*II, OutStreamer.GetCommentOS());
632 switch (II->getOpcode()) {
633 case TargetOpcode::PROLOG_LABEL:
634 case TargetOpcode::EH_LABEL:
635 case TargetOpcode::GC_LABEL:
636 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
638 case TargetOpcode::INLINEASM:
641 case TargetOpcode::DBG_VALUE:
643 if (!EmitDebugValueComment(II, *this))
647 case TargetOpcode::IMPLICIT_DEF:
648 if (isVerbose()) EmitImplicitDef(II, *this);
650 case TargetOpcode::KILL:
651 if (isVerbose()) EmitKill(II, *this);
658 if (ShouldPrintDebugScopes) {
659 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
665 // If the last instruction was a prolog label, then we have a situation where
666 // we emitted a prolog but no function body. This results in the ending prolog
667 // label equaling the end of function label and an invalid "row" in the
668 // FDE. We need to emit a noop in this situation so that the FDE's rows are
670 bool RequiresNoop = LastMI && LastMI->isPrologLabel();
672 // If the function is empty and the object file uses .subsections_via_symbols,
673 // then we need to emit *something* to the function body to prevent the
674 // labels from collapsing together. Just emit a noop.
675 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
677 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
678 if (Noop.getOpcode()) {
679 OutStreamer.AddComment("avoids zero-length function");
680 OutStreamer.EmitInstruction(Noop);
681 } else // Target not mc-ized yet.
682 OutStreamer.EmitRawText(StringRef("\tnop\n"));
685 // Emit target-specific gunk after the function body.
686 EmitFunctionBodyEnd();
688 // If the target wants a .size directive for the size of the function, emit
690 if (MAI->hasDotTypeDotSizeDirective()) {
691 // Create a symbol for the end of function, so we can get the size as
692 // difference between the function label and the temp label.
693 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
694 OutStreamer.EmitLabel(FnEndLabel);
696 const MCExpr *SizeExp =
697 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
698 MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
700 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
703 // Emit post-function debug information.
705 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
709 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
714 // Print out jump tables referenced by the function.
717 OutStreamer.AddBlankLine();
720 /// getDebugValueLocation - Get location information encoded by DBG_VALUE
722 MachineLocation AsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
723 // Target specific DBG_VALUE instructions are handled by each target.
724 return MachineLocation();
727 bool AsmPrinter::doFinalization(Module &M) {
728 // Emit global variables.
729 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
731 EmitGlobalVariable(I);
733 // Finalize debug and EH information.
736 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
743 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
749 // If the target wants to know about weak references, print them all.
750 if (MAI->getWeakRefDirective()) {
751 // FIXME: This is not lazy, it would be nice to only print weak references
752 // to stuff that is actually used. Note that doing so would require targets
753 // to notice uses in operands (due to constant exprs etc). This should
754 // happen with the MC stuff eventually.
756 // Print out module-level global variables here.
757 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
759 if (!I->hasExternalWeakLinkage()) continue;
760 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
763 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
764 if (!I->hasExternalWeakLinkage()) continue;
765 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
769 if (MAI->hasSetDirective()) {
770 OutStreamer.AddBlankLine();
771 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
773 MCSymbol *Name = Mang->getSymbol(I);
775 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
776 MCSymbol *Target = Mang->getSymbol(GV);
778 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
779 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
780 else if (I->hasWeakLinkage())
781 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
783 assert(I->hasLocalLinkage() && "Invalid alias linkage");
785 EmitVisibility(Name, I->getVisibility());
787 // Emit the directives as assignments aka .set:
788 OutStreamer.EmitAssignment(Name,
789 MCSymbolRefExpr::Create(Target, OutContext));
793 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
794 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
795 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
796 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
797 MP->finishAssembly(*this);
799 // If we don't have any trampolines, then we don't require stack memory
800 // to be executable. Some targets have a directive to declare this.
801 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
802 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
803 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
804 OutStreamer.SwitchSection(S);
806 // Allow the target to emit any magic that it wants at the end of the file,
807 // after everything else has gone out.
810 delete Mang; Mang = 0;
813 OutStreamer.Finish();
817 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
819 // Get the function symbol.
820 CurrentFnSym = Mang->getSymbol(MF.getFunction());
823 LI = &getAnalysis<MachineLoopInfo>();
827 // SectionCPs - Keep track the alignment, constpool entries per Section.
831 SmallVector<unsigned, 4> CPEs;
832 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
836 /// EmitConstantPool - Print to the current output stream assembly
837 /// representations of the constants in the constant pool MCP. This is
838 /// used to print out constants which have been "spilled to memory" by
839 /// the code generator.
841 void AsmPrinter::EmitConstantPool() {
842 const MachineConstantPool *MCP = MF->getConstantPool();
843 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
844 if (CP.empty()) return;
846 // Calculate sections for constant pool entries. We collect entries to go into
847 // the same section together to reduce amount of section switch statements.
848 SmallVector<SectionCPs, 4> CPSections;
849 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
850 const MachineConstantPoolEntry &CPE = CP[i];
851 unsigned Align = CPE.getAlignment();
854 switch (CPE.getRelocationInfo()) {
855 default: llvm_unreachable("Unknown section kind");
856 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
858 Kind = SectionKind::getReadOnlyWithRelLocal();
861 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
862 case 4: Kind = SectionKind::getMergeableConst4(); break;
863 case 8: Kind = SectionKind::getMergeableConst8(); break;
864 case 16: Kind = SectionKind::getMergeableConst16();break;
865 default: Kind = SectionKind::getMergeableConst(); break;
869 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
871 // The number of sections are small, just do a linear search from the
872 // last section to the first.
874 unsigned SecIdx = CPSections.size();
875 while (SecIdx != 0) {
876 if (CPSections[--SecIdx].S == S) {
882 SecIdx = CPSections.size();
883 CPSections.push_back(SectionCPs(S, Align));
886 if (Align > CPSections[SecIdx].Alignment)
887 CPSections[SecIdx].Alignment = Align;
888 CPSections[SecIdx].CPEs.push_back(i);
891 // Now print stuff into the calculated sections.
892 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
893 OutStreamer.SwitchSection(CPSections[i].S);
894 EmitAlignment(Log2_32(CPSections[i].Alignment));
897 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
898 unsigned CPI = CPSections[i].CPEs[j];
899 MachineConstantPoolEntry CPE = CP[CPI];
901 // Emit inter-object padding for alignment.
902 unsigned AlignMask = CPE.getAlignment() - 1;
903 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
904 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
906 const Type *Ty = CPE.getType();
907 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
909 // Emit the label with a comment on it.
911 OutStreamer.GetCommentOS() << "constant pool ";
912 WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
913 MF->getFunction()->getParent());
914 OutStreamer.GetCommentOS() << '\n';
916 OutStreamer.EmitLabel(GetCPISymbol(CPI));
918 if (CPE.isMachineConstantPoolEntry())
919 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
921 EmitGlobalConstant(CPE.Val.ConstVal);
926 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
927 /// by the current function to the current output stream.
929 void AsmPrinter::EmitJumpTableInfo() {
930 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
931 if (MJTI == 0) return;
932 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
933 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
934 if (JT.empty()) return;
936 // Pick the directive to use to print the jump table entries, and switch to
937 // the appropriate section.
938 const Function *F = MF->getFunction();
939 bool JTInDiffSection = false;
940 if (// In PIC mode, we need to emit the jump table to the same section as the
941 // function body itself, otherwise the label differences won't make sense.
942 // FIXME: Need a better predicate for this: what about custom entries?
943 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
944 // We should also do if the section name is NULL or function is declared
945 // in discardable section
946 // FIXME: this isn't the right predicate, should be based on the MCSection
948 F->isWeakForLinker()) {
949 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
951 // Otherwise, drop it in the readonly section.
952 const MCSection *ReadOnlySection =
953 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
954 OutStreamer.SwitchSection(ReadOnlySection);
955 JTInDiffSection = true;
958 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
960 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
961 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
963 // If this jump table was deleted, ignore it.
964 if (JTBBs.empty()) continue;
966 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
967 // .set directive for each unique entry. This reduces the number of
968 // relocations the assembler will generate for the jump table.
969 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
970 MAI->hasSetDirective()) {
971 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
972 const TargetLowering *TLI = TM.getTargetLowering();
973 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
974 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
975 const MachineBasicBlock *MBB = JTBBs[ii];
976 if (!EmittedSets.insert(MBB)) continue;
978 // .set LJTSet, LBB32-base
980 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
981 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
982 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
986 // On some targets (e.g. Darwin) we want to emit two consequtive labels
987 // before each jump table. The first label is never referenced, but tells
988 // the assembler and linker the extents of the jump table object. The
989 // second label is actually referenced by the code.
990 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
991 // FIXME: This doesn't have to have any specific name, just any randomly
992 // named and numbered 'l' label would work. Simplify GetJTISymbol.
993 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
995 OutStreamer.EmitLabel(GetJTISymbol(JTI));
997 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
998 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1002 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1004 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1005 const MachineBasicBlock *MBB,
1006 unsigned UID) const {
1007 const MCExpr *Value = 0;
1008 switch (MJTI->getEntryKind()) {
1009 case MachineJumpTableInfo::EK_Inline:
1010 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
1011 case MachineJumpTableInfo::EK_Custom32:
1012 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1015 case MachineJumpTableInfo::EK_BlockAddress:
1016 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1018 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1020 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1021 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1022 // with a relocation as gp-relative, e.g.:
1024 MCSymbol *MBBSym = MBB->getSymbol();
1025 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1029 case MachineJumpTableInfo::EK_LabelDifference32: {
1030 // EK_LabelDifference32 - Each entry is the address of the block minus
1031 // the address of the jump table. This is used for PIC jump tables where
1032 // gprel32 is not supported. e.g.:
1033 // .word LBB123 - LJTI1_2
1034 // If the .set directive is supported, this is emitted as:
1035 // .set L4_5_set_123, LBB123 - LJTI1_2
1036 // .word L4_5_set_123
1038 // If we have emitted set directives for the jump table entries, print
1039 // them rather than the entries themselves. If we're emitting PIC, then
1040 // emit the table entries as differences between two text section labels.
1041 if (MAI->hasSetDirective()) {
1042 // If we used .set, reference the .set's symbol.
1043 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1047 // Otherwise, use the difference as the jump table entry.
1048 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1049 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1050 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1055 assert(Value && "Unknown entry kind!");
1057 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
1058 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
1062 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1063 /// special global used by LLVM. If so, emit it and return true, otherwise
1064 /// do nothing and return false.
1065 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1066 if (GV->getName() == "llvm.used") {
1067 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1068 EmitLLVMUsedList(GV->getInitializer());
1072 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1073 if (GV->getSection() == "llvm.metadata" ||
1074 GV->hasAvailableExternallyLinkage())
1077 if (!GV->hasAppendingLinkage()) return false;
1079 assert(GV->hasInitializer() && "Not a special LLVM global!");
1081 const TargetData *TD = TM.getTargetData();
1082 unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1083 if (GV->getName() == "llvm.global_ctors") {
1084 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1085 EmitAlignment(Align);
1086 EmitXXStructorList(GV->getInitializer());
1088 if (TM.getRelocationModel() == Reloc::Static &&
1089 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1090 StringRef Sym(".constructors_used");
1091 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1097 if (GV->getName() == "llvm.global_dtors") {
1098 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1099 EmitAlignment(Align);
1100 EmitXXStructorList(GV->getInitializer());
1102 if (TM.getRelocationModel() == Reloc::Static &&
1103 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1104 StringRef Sym(".destructors_used");
1105 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1114 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1115 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1116 /// is true, as being used with this directive.
1117 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1118 // Should be an array of 'i8*'.
1119 ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1120 if (InitList == 0) return;
1122 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1123 const GlobalValue *GV =
1124 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1125 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1126 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1130 /// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
1131 /// function pointers, ignoring the init priority.
1132 void AsmPrinter::EmitXXStructorList(Constant *List) {
1133 // Should be an array of '{ int, void ()* }' structs. The first value is the
1134 // init priority, which we ignore.
1135 if (!isa<ConstantArray>(List)) return;
1136 ConstantArray *InitList = cast<ConstantArray>(List);
1137 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1138 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1139 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
1141 if (CS->getOperand(1)->isNullValue())
1142 return; // Found a null terminator, exit printing.
1143 // Emit the function pointer.
1144 EmitGlobalConstant(CS->getOperand(1));
1148 //===--------------------------------------------------------------------===//
1149 // Emission and print routines
1152 /// EmitInt8 - Emit a byte directive and value.
1154 void AsmPrinter::EmitInt8(int Value) const {
1155 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1158 /// EmitInt16 - Emit a short directive and value.
1160 void AsmPrinter::EmitInt16(int Value) const {
1161 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1164 /// EmitInt32 - Emit a long directive and value.
1166 void AsmPrinter::EmitInt32(int Value) const {
1167 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1170 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1171 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1172 /// labels. This implicitly uses .set if it is available.
1173 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1174 unsigned Size) const {
1175 // Get the Hi-Lo expression.
1176 const MCExpr *Diff =
1177 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1178 MCSymbolRefExpr::Create(Lo, OutContext),
1181 if (!MAI->hasSetDirective()) {
1182 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1186 // Otherwise, emit with .set (aka assignment).
1187 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1188 OutStreamer.EmitAssignment(SetLabel, Diff);
1189 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1192 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1193 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1194 /// specify the labels. This implicitly uses .set if it is available.
1195 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1196 const MCSymbol *Lo, unsigned Size)
1199 // Emit Hi+Offset - Lo
1200 // Get the Hi+Offset expression.
1201 const MCExpr *Plus =
1202 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1203 MCConstantExpr::Create(Offset, OutContext),
1206 // Get the Hi+Offset-Lo expression.
1207 const MCExpr *Diff =
1208 MCBinaryExpr::CreateSub(Plus,
1209 MCSymbolRefExpr::Create(Lo, OutContext),
1212 if (!MAI->hasSetDirective())
1213 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1215 // Otherwise, emit with .set (aka assignment).
1216 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1217 OutStreamer.EmitAssignment(SetLabel, Diff);
1218 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1223 //===----------------------------------------------------------------------===//
1225 // EmitAlignment - Emit an alignment directive to the specified power of
1226 // two boundary. For example, if you pass in 3 here, you will get an 8
1227 // byte alignment. If a global value is specified, and if that global has
1228 // an explicit alignment requested, it will override the alignment request
1229 // if required for correctness.
1231 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1232 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
1234 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1236 if (getCurrentSection()->getKind().isText())
1237 OutStreamer.EmitCodeAlignment(1 << NumBits);
1239 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1242 //===----------------------------------------------------------------------===//
1243 // Constant emission.
1244 //===----------------------------------------------------------------------===//
1246 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1248 static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1249 MCContext &Ctx = AP.OutContext;
1251 if (CV->isNullValue() || isa<UndefValue>(CV))
1252 return MCConstantExpr::Create(0, Ctx);
1254 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1255 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1257 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1258 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1260 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1261 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1263 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1265 llvm_unreachable("Unknown constant value to lower!");
1266 return MCConstantExpr::Create(0, Ctx);
1269 switch (CE->getOpcode()) {
1271 // If the code isn't optimized, there may be outstanding folding
1272 // opportunities. Attempt to fold the expression using TargetData as a
1273 // last resort before giving up.
1275 ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1277 return LowerConstant(C, AP);
1279 // Otherwise report the problem to the user.
1282 raw_string_ostream OS(S);
1283 OS << "Unsupported expression in static initializer: ";
1284 WriteAsOperand(OS, CE, /*PrintType=*/false,
1285 !AP.MF ? 0 : AP.MF->getFunction()->getParent());
1286 report_fatal_error(OS.str());
1288 return MCConstantExpr::Create(0, Ctx);
1289 case Instruction::GetElementPtr: {
1290 const TargetData &TD = *AP.TM.getTargetData();
1291 // Generate a symbolic expression for the byte address
1292 const Constant *PtrVal = CE->getOperand(0);
1293 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1294 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1297 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1301 // Truncate/sext the offset to the pointer size.
1302 if (TD.getPointerSizeInBits() != 64) {
1303 int SExtAmount = 64-TD.getPointerSizeInBits();
1304 Offset = (Offset << SExtAmount) >> SExtAmount;
1307 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1311 case Instruction::Trunc:
1312 // We emit the value and depend on the assembler to truncate the generated
1313 // expression properly. This is important for differences between
1314 // blockaddress labels. Since the two labels are in the same function, it
1315 // is reasonable to treat their delta as a 32-bit value.
1317 case Instruction::BitCast:
1318 return LowerConstant(CE->getOperand(0), AP);
1320 case Instruction::IntToPtr: {
1321 const TargetData &TD = *AP.TM.getTargetData();
1322 // Handle casts to pointers by changing them into casts to the appropriate
1323 // integer type. This promotes constant folding and simplifies this code.
1324 Constant *Op = CE->getOperand(0);
1325 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1327 return LowerConstant(Op, AP);
1330 case Instruction::PtrToInt: {
1331 const TargetData &TD = *AP.TM.getTargetData();
1332 // Support only foldable casts to/from pointers that can be eliminated by
1333 // changing the pointer to the appropriately sized integer type.
1334 Constant *Op = CE->getOperand(0);
1335 const Type *Ty = CE->getType();
1337 const MCExpr *OpExpr = LowerConstant(Op, AP);
1339 // We can emit the pointer value into this slot if the slot is an
1340 // integer slot equal to the size of the pointer.
1341 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1344 // Otherwise the pointer is smaller than the resultant integer, mask off
1345 // the high bits so we are sure to get a proper truncation if the input is
1347 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1348 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1349 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1352 // The MC library also has a right-shift operator, but it isn't consistently
1353 // signed or unsigned between different targets.
1354 case Instruction::Add:
1355 case Instruction::Sub:
1356 case Instruction::Mul:
1357 case Instruction::SDiv:
1358 case Instruction::SRem:
1359 case Instruction::Shl:
1360 case Instruction::And:
1361 case Instruction::Or:
1362 case Instruction::Xor: {
1363 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1364 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1365 switch (CE->getOpcode()) {
1366 default: llvm_unreachable("Unknown binary operator constant cast expr");
1367 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1368 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1369 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1370 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1371 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1372 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1373 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1374 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1375 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1381 static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1384 static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1386 if (AddrSpace != 0 || !CA->isString()) {
1387 // Not a string. Print the values in successive locations
1388 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1389 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1393 // Otherwise, it can be emitted as .ascii.
1394 SmallVector<char, 128> TmpVec;
1395 TmpVec.reserve(CA->getNumOperands());
1396 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1397 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1399 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1402 static void EmitGlobalConstantVector(const ConstantVector *CV,
1403 unsigned AddrSpace, AsmPrinter &AP) {
1404 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1405 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1408 static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1409 unsigned AddrSpace, AsmPrinter &AP) {
1410 // Print the fields in successive locations. Pad to align if needed!
1411 const TargetData *TD = AP.TM.getTargetData();
1412 unsigned Size = TD->getTypeAllocSize(CS->getType());
1413 const StructLayout *Layout = TD->getStructLayout(CS->getType());
1414 uint64_t SizeSoFar = 0;
1415 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1416 const Constant *Field = CS->getOperand(i);
1418 // Check if padding is needed and insert one or more 0s.
1419 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1420 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1421 - Layout->getElementOffset(i)) - FieldSize;
1422 SizeSoFar += FieldSize + PadSize;
1424 // Now print the actual field value.
1425 EmitGlobalConstantImpl(Field, AddrSpace, AP);
1427 // Insert padding - this may include padding to increase the size of the
1428 // current field up to the ABI size (if the struct is not packed) as well
1429 // as padding to ensure that the next field starts at the right offset.
1430 AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1432 assert(SizeSoFar == Layout->getSizeInBytes() &&
1433 "Layout of constant struct may be incorrect!");
1436 static void EmitGlobalConstantUnion(const ConstantUnion *CU,
1437 unsigned AddrSpace, AsmPrinter &AP) {
1438 const TargetData *TD = AP.TM.getTargetData();
1439 unsigned Size = TD->getTypeAllocSize(CU->getType());
1441 const Constant *Contents = CU->getOperand(0);
1442 unsigned FilledSize = TD->getTypeAllocSize(Contents->getType());
1444 // Print the actually filled part
1445 EmitGlobalConstantImpl(Contents, AddrSpace, AP);
1447 // And pad with enough zeroes
1448 AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace);
1451 static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1453 // FP Constants are printed as integer constants to avoid losing
1455 if (CFP->getType()->isDoubleTy()) {
1456 if (AP.isVerbose()) {
1457 double Val = CFP->getValueAPF().convertToDouble();
1458 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1461 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1462 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1466 if (CFP->getType()->isFloatTy()) {
1467 if (AP.isVerbose()) {
1468 float Val = CFP->getValueAPF().convertToFloat();
1469 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1471 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1472 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1476 if (CFP->getType()->isX86_FP80Ty()) {
1477 // all long double variants are printed as hex
1478 // API needed to prevent premature destruction
1479 APInt API = CFP->getValueAPF().bitcastToAPInt();
1480 const uint64_t *p = API.getRawData();
1481 if (AP.isVerbose()) {
1482 // Convert to double so we can print the approximate val as a comment.
1483 APFloat DoubleVal = CFP->getValueAPF();
1485 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1487 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1488 << DoubleVal.convertToDouble() << '\n';
1491 if (AP.TM.getTargetData()->isBigEndian()) {
1492 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1493 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1495 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1496 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1499 // Emit the tail padding for the long double.
1500 const TargetData &TD = *AP.TM.getTargetData();
1501 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1502 TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1506 assert(CFP->getType()->isPPC_FP128Ty() &&
1507 "Floating point constant type not handled");
1508 // All long double variants are printed as hex
1509 // API needed to prevent premature destruction.
1510 APInt API = CFP->getValueAPF().bitcastToAPInt();
1511 const uint64_t *p = API.getRawData();
1512 if (AP.TM.getTargetData()->isBigEndian()) {
1513 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1514 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1516 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1517 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1521 static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1522 unsigned AddrSpace, AsmPrinter &AP) {
1523 const TargetData *TD = AP.TM.getTargetData();
1524 unsigned BitWidth = CI->getBitWidth();
1525 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1527 // We don't expect assemblers to support integer data directives
1528 // for more than 64 bits, so we emit the data in at most 64-bit
1529 // quantities at a time.
1530 const uint64_t *RawData = CI->getValue().getRawData();
1531 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1532 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1533 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1537 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1539 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1540 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1541 return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1544 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1545 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1552 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1553 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1556 EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1561 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1562 return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1564 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1565 return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1567 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1568 return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1570 if (isa<ConstantPointerNull>(CV)) {
1571 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1572 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1576 if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV))
1577 return EmitGlobalConstantUnion(CVU, AddrSpace, AP);
1579 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1580 return EmitGlobalConstantVector(V, AddrSpace, AP);
1582 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
1583 // thread the streamer with EmitValue.
1584 AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1585 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1589 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1590 void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1591 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1593 EmitGlobalConstantImpl(CV, AddrSpace, *this);
1594 else if (MAI->hasSubsectionsViaSymbols()) {
1595 // If the global has zero size, emit a single byte so that two labels don't
1596 // look like they are at the same location.
1597 OutStreamer.EmitIntValue(0, 1, AddrSpace);
1601 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1602 // Target doesn't support this yet!
1603 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1606 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1608 OS << '+' << Offset;
1609 else if (Offset < 0)
1613 //===----------------------------------------------------------------------===//
1614 // Symbol Lowering Routines.
1615 //===----------------------------------------------------------------------===//
1617 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1618 /// temporary label with the specified stem and unique ID.
1619 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1620 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1624 /// GetTempSymbol - Return an assembler temporary label with the specified
1626 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1627 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1632 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1633 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1636 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1637 return MMI->getAddrLabelSymbol(BB);
1640 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
1641 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1642 return OutContext.GetOrCreateSymbol
1643 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1644 + "_" + Twine(CPID));
1647 /// GetJTISymbol - Return the symbol for the specified jump table entry.
1648 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1649 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1652 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
1653 /// FIXME: privatize to AsmPrinter.
1654 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1655 return OutContext.GetOrCreateSymbol
1656 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1657 Twine(UID) + "_set_" + Twine(MBBID));
1660 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1661 /// global value name as its base, with the specified suffix, and where the
1662 /// symbol is forced to have private linkage if ForcePrivate is true.
1663 MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1665 bool ForcePrivate) const {
1666 SmallString<60> NameStr;
1667 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1668 NameStr.append(Suffix.begin(), Suffix.end());
1669 return OutContext.GetOrCreateSymbol(NameStr.str());
1672 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1674 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1675 SmallString<60> NameStr;
1676 Mang->getNameWithPrefix(NameStr, Sym);
1677 return OutContext.GetOrCreateSymbol(NameStr.str());
1682 /// PrintParentLoopComment - Print comments about parent loops of this one.
1683 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1684 unsigned FunctionNumber) {
1685 if (Loop == 0) return;
1686 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1687 OS.indent(Loop->getLoopDepth()*2)
1688 << "Parent Loop BB" << FunctionNumber << "_"
1689 << Loop->getHeader()->getNumber()
1690 << " Depth=" << Loop->getLoopDepth() << '\n';
1694 /// PrintChildLoopComment - Print comments about child loops within
1695 /// the loop for this basic block, with nesting.
1696 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1697 unsigned FunctionNumber) {
1698 // Add child loop information
1699 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1700 OS.indent((*CL)->getLoopDepth()*2)
1701 << "Child Loop BB" << FunctionNumber << "_"
1702 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1704 PrintChildLoopComment(OS, *CL, FunctionNumber);
1708 /// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1709 static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1710 const MachineLoopInfo *LI,
1711 const AsmPrinter &AP) {
1712 // Add loop depth information
1713 const MachineLoop *Loop = LI->getLoopFor(&MBB);
1714 if (Loop == 0) return;
1716 MachineBasicBlock *Header = Loop->getHeader();
1717 assert(Header && "No header for loop");
1719 // If this block is not a loop header, just print out what is the loop header
1721 if (Header != &MBB) {
1722 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
1723 Twine(AP.getFunctionNumber())+"_" +
1724 Twine(Loop->getHeader()->getNumber())+
1725 " Depth="+Twine(Loop->getLoopDepth()));
1729 // Otherwise, it is a loop header. Print out information about child and
1731 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1733 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1736 OS.indent(Loop->getLoopDepth()*2-2);
1741 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1743 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1747 /// EmitBasicBlockStart - This method prints the label for the specified
1748 /// MachineBasicBlock, an alignment (if present) and a comment describing
1749 /// it if appropriate.
1750 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1751 // Emit an alignment directive for this block, if needed.
1752 if (unsigned Align = MBB->getAlignment())
1753 EmitAlignment(Log2_32(Align));
1755 // If the block has its address taken, emit any labels that were used to
1756 // reference the block. It is possible that there is more than one label
1757 // here, because multiple LLVM BB's may have been RAUW'd to this block after
1758 // the references were generated.
1759 if (MBB->hasAddressTaken()) {
1760 const BasicBlock *BB = MBB->getBasicBlock();
1762 OutStreamer.AddComment("Block address taken");
1764 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1766 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1767 OutStreamer.EmitLabel(Syms[i]);
1770 // Print the main label for the block.
1771 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1772 if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1773 if (const BasicBlock *BB = MBB->getBasicBlock())
1775 OutStreamer.AddComment("%" + BB->getName());
1777 EmitBasicBlockLoopComments(*MBB, LI, *this);
1779 // NOTE: Want this comment at start of line, don't emit with AddComment.
1780 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1781 Twine(MBB->getNumber()) + ":");
1785 if (const BasicBlock *BB = MBB->getBasicBlock())
1787 OutStreamer.AddComment("%" + BB->getName());
1788 EmitBasicBlockLoopComments(*MBB, LI, *this);
1791 OutStreamer.EmitLabel(MBB->getSymbol());
1795 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1796 MCSymbolAttr Attr = MCSA_Invalid;
1798 switch (Visibility) {
1800 case GlobalValue::HiddenVisibility:
1801 Attr = MAI->getHiddenVisibilityAttr();
1803 case GlobalValue::ProtectedVisibility:
1804 Attr = MAI->getProtectedVisibilityAttr();
1808 if (Attr != MCSA_Invalid)
1809 OutStreamer.EmitSymbolAttribute(Sym, Attr);
1812 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
1813 /// exactly one predecessor and the control transfer mechanism between
1814 /// the predecessor and this block is a fall-through.
1816 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1817 // If this is a landing pad, it isn't a fall through. If it has no preds,
1818 // then nothing falls through to it.
1819 if (MBB->isLandingPad() || MBB->pred_empty())
1822 // If there isn't exactly one predecessor, it can't be a fall through.
1823 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1825 if (PI2 != MBB->pred_end())
1828 // The predecessor has to be immediately before this block.
1829 const MachineBasicBlock *Pred = *PI;
1831 if (!Pred->isLayoutSuccessor(MBB))
1834 // If the block is completely empty, then it definitely does fall through.
1838 // Otherwise, check the last instruction.
1839 const MachineInstr &LastInst = Pred->back();
1840 return !LastInst.getDesc().isBarrier();
1845 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1846 if (!S->usesMetadata())
1849 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1850 gcp_map_type::iterator GCPI = GCMap.find(S);
1851 if (GCPI != GCMap.end())
1852 return GCPI->second;
1854 const char *Name = S->getName().c_str();
1856 for (GCMetadataPrinterRegistry::iterator
1857 I = GCMetadataPrinterRegistry::begin(),
1858 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1859 if (strcmp(Name, I->getName()) == 0) {
1860 GCMetadataPrinter *GMP = I->instantiate();
1862 GCMap.insert(std::make_pair(S, GMP));
1866 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));