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/TargetAsmInfo.h"
37 #include "llvm/Target/TargetData.h"
38 #include "llvm/Target/TargetInstrInfo.h"
39 #include "llvm/Target/TargetLowering.h"
40 #include "llvm/Target/TargetLoweringObjectFile.h"
41 #include "llvm/Target/TargetRegisterInfo.h"
42 #include "llvm/Assembly/Writer.h"
43 #include "llvm/ADT/SmallString.h"
44 #include "llvm/ADT/Statistic.h"
45 #include "llvm/Support/ErrorHandling.h"
46 #include "llvm/Support/Format.h"
47 #include "llvm/Support/Timer.h"
50 static const char *DWARFGroupName = "DWARF Emission";
51 static const char *DbgTimerName = "DWARF Debug Writer";
52 static const char *EHTimerName = "DWARF Exception Writer";
54 STATISTIC(EmittedInsts, "Number of machine instrs printed");
56 char AsmPrinter::ID = 0;
58 typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
59 static gcp_map_type &getGCMap(void *&P) {
61 P = new gcp_map_type();
62 return *(gcp_map_type*)P;
66 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
67 /// value in log2 form. This rounds up to the preferred alignment if possible
69 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const TargetData &TD,
70 unsigned InBits = 0) {
72 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
73 NumBits = TD.getPreferredAlignmentLog(GVar);
75 // If InBits is specified, round it to it.
79 // If the GV has a specified alignment, take it into account.
80 if (GV->getAlignment() == 0)
83 unsigned GVAlign = Log2_32(GV->getAlignment());
85 // If the GVAlign is larger than NumBits, or if we are required to obey
86 // NumBits because the GV has an assigned section, obey it.
87 if (GVAlign > NumBits || GV->hasSection())
95 AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
96 : MachineFunctionPass(ID),
97 TM(tm), MAI(tm.getMCAsmInfo()),
98 OutContext(Streamer.getContext()),
99 OutStreamer(Streamer),
100 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
101 DD = 0; DE = 0; MMI = 0; LI = 0;
102 GCMetadataPrinters = 0;
103 VerboseAsm = Streamer.isVerboseAsm();
106 AsmPrinter::~AsmPrinter() {
107 assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized");
109 if (GCMetadataPrinters != 0) {
110 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
112 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
115 GCMetadataPrinters = 0;
121 /// getFunctionNumber - Return a unique ID for the current function.
123 unsigned AsmPrinter::getFunctionNumber() const {
124 return MF->getFunctionNumber();
127 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
128 return TM.getTargetLowering()->getObjFileLowering();
132 /// getTargetData - Return information about data layout.
133 const TargetData &AsmPrinter::getTargetData() const {
134 return *TM.getTargetData();
137 /// getCurrentSection() - Return the current section we are emitting to.
138 const MCSection *AsmPrinter::getCurrentSection() const {
139 return OutStreamer.getCurrentSection();
144 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
145 AU.setPreservesAll();
146 MachineFunctionPass::getAnalysisUsage(AU);
147 AU.addRequired<MachineModuleInfo>();
148 AU.addRequired<GCModuleInfo>();
150 AU.addRequired<MachineLoopInfo>();
153 bool AsmPrinter::doInitialization(Module &M) {
154 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
155 MMI->AnalyzeModule(M);
157 // Initialize TargetLoweringObjectFile.
158 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
159 .Initialize(OutContext, TM);
161 Mang = new Mangler(OutContext, *TM.getTargetData());
163 // Allow the target to emit any magic that it wants at the start of the file.
164 EmitStartOfAsmFile(M);
166 // Very minimal debug info. It is ignored if we emit actual debug info. If we
167 // don't, this at least helps the user find where a global came from.
168 if (MAI->hasSingleParameterDotFile()) {
170 OutStreamer.EmitFileDirective(M.getModuleIdentifier());
173 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
174 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
175 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
176 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
177 MP->beginAssembly(*this);
179 // Emit module-level inline asm if it exists.
180 if (!M.getModuleInlineAsm().empty()) {
181 OutStreamer.AddComment("Start of file scope inline assembly");
182 OutStreamer.AddBlankLine();
183 EmitInlineAsm(M.getModuleInlineAsm()+"\n");
184 OutStreamer.AddComment("End of file scope inline assembly");
185 OutStreamer.AddBlankLine();
188 if (MAI->doesSupportDebugInformation())
189 DD = new DwarfDebug(this, &M);
191 if (MAI->doesSupportExceptionHandling())
192 switch (MAI->getExceptionHandlingType()) {
194 case ExceptionHandling::DwarfTable:
195 DE = new DwarfTableException(this);
197 case ExceptionHandling::DwarfCFI:
198 DE = new DwarfCFIException(this);
200 case ExceptionHandling::ARM:
201 DE = new ARMException(this);
208 void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
209 switch ((GlobalValue::LinkageTypes)Linkage) {
210 case GlobalValue::CommonLinkage:
211 case GlobalValue::LinkOnceAnyLinkage:
212 case GlobalValue::LinkOnceODRLinkage:
213 case GlobalValue::WeakAnyLinkage:
214 case GlobalValue::WeakODRLinkage:
215 case GlobalValue::LinkerPrivateWeakLinkage:
216 case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
217 if (MAI->getWeakDefDirective() != 0) {
219 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
221 if ((GlobalValue::LinkageTypes)Linkage !=
222 GlobalValue::LinkerPrivateWeakDefAutoLinkage)
223 // .weak_definition _foo
224 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
226 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
227 } else if (MAI->getLinkOnceDirective() != 0) {
229 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
230 //NOTE: linkonce is handled by the section the symbol was assigned to.
233 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
236 case GlobalValue::DLLExportLinkage:
237 case GlobalValue::AppendingLinkage:
238 // FIXME: appending linkage variables should go into a section of
239 // their name or something. For now, just emit them as external.
240 case GlobalValue::ExternalLinkage:
241 // If external or appending, declare as a global symbol.
243 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
245 case GlobalValue::PrivateLinkage:
246 case GlobalValue::InternalLinkage:
247 case GlobalValue::LinkerPrivateLinkage:
250 llvm_unreachable("Unknown linkage type!");
255 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
256 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
257 if (GV->hasInitializer()) {
258 // Check to see if this is a special global used by LLVM, if so, emit it.
259 if (EmitSpecialLLVMGlobal(GV))
263 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
264 /*PrintType=*/false, GV->getParent());
265 OutStreamer.GetCommentOS() << '\n';
269 MCSymbol *GVSym = Mang->getSymbol(GV);
270 EmitVisibility(GVSym, GV->getVisibility());
272 if (!GV->hasInitializer()) // External globals require no extra code.
275 if (MAI->hasDotTypeDotSizeDirective())
276 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
278 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
280 const TargetData *TD = TM.getTargetData();
281 uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());
283 // If the alignment is specified, we *must* obey it. Overaligning a global
284 // with a specified alignment is a prompt way to break globals emitted to
285 // sections and expected to be contiguous (e.g. ObjC metadata).
286 unsigned AlignLog = getGVAlignmentLog2(GV, *TD);
288 // Handle common and BSS local symbols (.lcomm).
289 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
290 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
292 // Handle common symbols.
293 if (GVKind.isCommon()) {
294 unsigned Align = 1 << AlignLog;
295 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
299 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
303 // Handle local BSS symbols.
304 if (MAI->hasMachoZeroFillDirective()) {
305 const MCSection *TheSection =
306 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
307 // .zerofill __DATA, __bss, _foo, 400, 5
308 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
312 if (MAI->hasLCOMMDirective()) {
314 OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
318 unsigned Align = 1 << AlignLog;
319 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
323 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
325 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
329 const MCSection *TheSection =
330 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
332 // Handle the zerofill directive on darwin, which is a special form of BSS
334 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
335 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
338 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
339 // .zerofill __DATA, __common, _foo, 400, 5
340 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
344 // Handle thread local data for mach-o which requires us to output an
345 // additional structure of data and mangle the original symbol so that we
346 // can reference it later.
348 // TODO: This should become an "emit thread local global" method on TLOF.
349 // All of this macho specific stuff should be sunk down into TLOFMachO and
350 // stuff like "TLSExtraDataSection" should no longer be part of the parent
351 // TLOF class. This will also make it more obvious that stuff like
352 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
354 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
355 // Emit the .tbss symbol
357 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
359 if (GVKind.isThreadBSS())
360 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
361 else if (GVKind.isThreadData()) {
362 OutStreamer.SwitchSection(TheSection);
364 EmitAlignment(AlignLog, GV);
365 OutStreamer.EmitLabel(MangSym);
367 EmitGlobalConstant(GV->getInitializer());
370 OutStreamer.AddBlankLine();
372 // Emit the variable struct for the runtime.
373 const MCSection *TLVSect
374 = getObjFileLowering().getTLSExtraDataSection();
376 OutStreamer.SwitchSection(TLVSect);
377 // Emit the linkage here.
378 EmitLinkage(GV->getLinkage(), GVSym);
379 OutStreamer.EmitLabel(GVSym);
381 // Three pointers in size:
382 // - __tlv_bootstrap - used to make sure support exists
383 // - spare pointer, used when mapped by the runtime
384 // - pointer to mangled symbol above with initializer
385 unsigned PtrSize = TD->getPointerSizeInBits()/8;
386 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
388 OutStreamer.EmitIntValue(0, PtrSize, 0);
389 OutStreamer.EmitSymbolValue(MangSym, PtrSize, 0);
391 OutStreamer.AddBlankLine();
395 OutStreamer.SwitchSection(TheSection);
397 EmitLinkage(GV->getLinkage(), GVSym);
398 EmitAlignment(AlignLog, GV);
400 OutStreamer.EmitLabel(GVSym);
402 EmitGlobalConstant(GV->getInitializer());
404 if (MAI->hasDotTypeDotSizeDirective())
406 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
408 OutStreamer.AddBlankLine();
411 /// EmitFunctionHeader - This method emits the header for the current
413 void AsmPrinter::EmitFunctionHeader() {
414 // Print out constants referenced by the function
417 // Print the 'header' of function.
418 const Function *F = MF->getFunction();
420 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
421 EmitVisibility(CurrentFnSym, F->getVisibility());
423 EmitLinkage(F->getLinkage(), CurrentFnSym);
424 EmitAlignment(MF->getAlignment(), F);
426 if (MAI->hasDotTypeDotSizeDirective())
427 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
430 WriteAsOperand(OutStreamer.GetCommentOS(), F,
431 /*PrintType=*/false, F->getParent());
432 OutStreamer.GetCommentOS() << '\n';
435 // Emit the CurrentFnSym. This is a virtual function to allow targets to
436 // do their wild and crazy things as required.
437 EmitFunctionEntryLabel();
439 // If the function had address-taken blocks that got deleted, then we have
440 // references to the dangling symbols. Emit them at the start of the function
441 // so that we don't get references to undefined symbols.
442 std::vector<MCSymbol*> DeadBlockSyms;
443 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
444 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
445 OutStreamer.AddComment("Address taken block that was later removed");
446 OutStreamer.EmitLabel(DeadBlockSyms[i]);
449 // Add some workaround for linkonce linkage on Cygwin\MinGW.
450 if (MAI->getLinkOnceDirective() != 0 &&
451 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
452 // FIXME: What is this?
454 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
455 CurrentFnSym->getName());
456 OutStreamer.EmitLabel(FakeStub);
459 // Emit pre-function debug and/or EH information.
461 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
462 DE->BeginFunction(MF);
465 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
466 DD->beginFunction(MF);
470 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
471 /// function. This can be overridden by targets as required to do custom stuff.
472 void AsmPrinter::EmitFunctionEntryLabel() {
473 // The function label could have already been emitted if two symbols end up
474 // conflicting due to asm renaming. Detect this and emit an error.
475 if (CurrentFnSym->isUndefined())
476 return OutStreamer.EmitLabel(CurrentFnSym);
478 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
479 "' label emitted multiple times to assembly file");
483 /// EmitComments - Pretty-print comments for instructions.
484 static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
485 const MachineFunction *MF = MI.getParent()->getParent();
486 const TargetMachine &TM = MF->getTarget();
488 // Check for spills and reloads
491 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
493 // We assume a single instruction only has a spill or reload, not
495 const MachineMemOperand *MMO;
496 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
497 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
498 MMO = *MI.memoperands_begin();
499 CommentOS << MMO->getSize() << "-byte Reload\n";
501 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
502 if (FrameInfo->isSpillSlotObjectIndex(FI))
503 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
504 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
505 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
506 MMO = *MI.memoperands_begin();
507 CommentOS << MMO->getSize() << "-byte Spill\n";
509 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
510 if (FrameInfo->isSpillSlotObjectIndex(FI))
511 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
514 // Check for spill-induced copies
515 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
516 CommentOS << " Reload Reuse\n";
519 /// EmitImplicitDef - This method emits the specified machine instruction
520 /// that is an implicit def.
521 static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
522 unsigned RegNo = MI->getOperand(0).getReg();
523 AP.OutStreamer.AddComment(Twine("implicit-def: ") +
524 AP.TM.getRegisterInfo()->getName(RegNo));
525 AP.OutStreamer.AddBlankLine();
528 static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
529 std::string Str = "kill:";
530 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
531 const MachineOperand &Op = MI->getOperand(i);
532 assert(Op.isReg() && "KILL instruction must have only register operands");
534 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
535 Str += (Op.isDef() ? "<def>" : "<kill>");
537 AP.OutStreamer.AddComment(Str);
538 AP.OutStreamer.AddBlankLine();
541 /// EmitDebugValueComment - This method handles the target-independent form
542 /// of DBG_VALUE, returning true if it was able to do so. A false return
543 /// means the target will need to handle MI in EmitInstruction.
544 static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
545 // This code handles only the 3-operand target-independent form.
546 if (MI->getNumOperands() != 3)
549 SmallString<128> Str;
550 raw_svector_ostream OS(Str);
551 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
553 // cast away const; DIetc do not take const operands for some reason.
554 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
555 if (V.getContext().isSubprogram())
556 OS << DISubprogram(V.getContext()).getDisplayName() << ":";
557 OS << V.getName() << " <- ";
559 // Register or immediate value. Register 0 means undef.
560 if (MI->getOperand(0).isFPImm()) {
561 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
562 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
563 OS << (double)APF.convertToFloat();
564 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
565 OS << APF.convertToDouble();
567 // There is no good way to print long double. Convert a copy to
568 // double. Ah well, it's only a comment.
570 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
572 OS << "(long double) " << APF.convertToDouble();
574 } else if (MI->getOperand(0).isImm()) {
575 OS << MI->getOperand(0).getImm();
577 assert(MI->getOperand(0).isReg() && "Unknown operand type");
578 if (MI->getOperand(0).getReg() == 0) {
579 // Suppress offset, it is not meaningful here.
581 // NOTE: Want this comment at start of line, don't emit with AddComment.
582 AP.OutStreamer.EmitRawText(OS.str());
585 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
588 OS << '+' << MI->getOperand(1).getImm();
589 // NOTE: Want this comment at start of line, don't emit with AddComment.
590 AP.OutStreamer.EmitRawText(OS.str());
594 void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
595 MCSymbol *Label = MI.getOperand(0).getMCSymbol();
597 if (MAI->doesDwarfRequireFrameSection() ||
598 MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
599 OutStreamer.EmitLabel(Label);
601 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
604 const MachineFunction &MF = *MI.getParent()->getParent();
605 MachineModuleInfo &MMI = MF.getMMI();
606 std::vector<MachineMove> &Moves = MMI.getFrameMoves();
607 bool FoundOne = false;
609 for (std::vector<MachineMove>::iterator I = Moves.begin(),
610 E = Moves.end(); I != E; ++I) {
611 if (I->getLabel() == Label) {
612 EmitCFIFrameMove(*I);
619 /// EmitFunctionBody - This method emits the body and trailer for a
621 void AsmPrinter::EmitFunctionBody() {
622 // Emit target-specific gunk before the function body.
623 EmitFunctionBodyStart();
625 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
627 // Print out code for the function.
628 bool HasAnyRealCode = false;
629 const MachineInstr *LastMI = 0;
630 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
632 // Print a label for the basic block.
633 EmitBasicBlockStart(I);
634 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
638 // Print the assembly for the instruction.
639 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
640 !II->isDebugValue()) {
641 HasAnyRealCode = true;
645 if (ShouldPrintDebugScopes) {
646 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
647 DD->beginInstruction(II);
651 EmitComments(*II, OutStreamer.GetCommentOS());
653 switch (II->getOpcode()) {
654 case TargetOpcode::PROLOG_LABEL:
655 emitPrologLabel(*II);
658 case TargetOpcode::EH_LABEL:
659 case TargetOpcode::GC_LABEL:
660 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
662 case TargetOpcode::INLINEASM:
665 case TargetOpcode::DBG_VALUE:
667 if (!EmitDebugValueComment(II, *this))
671 case TargetOpcode::IMPLICIT_DEF:
672 if (isVerbose()) EmitImplicitDef(II, *this);
674 case TargetOpcode::KILL:
675 if (isVerbose()) EmitKill(II, *this);
682 if (ShouldPrintDebugScopes) {
683 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
684 DD->endInstruction(II);
689 // If the last instruction was a prolog label, then we have a situation where
690 // we emitted a prolog but no function body. This results in the ending prolog
691 // label equaling the end of function label and an invalid "row" in the
692 // FDE. We need to emit a noop in this situation so that the FDE's rows are
694 bool RequiresNoop = LastMI && LastMI->isPrologLabel();
696 // If the function is empty and the object file uses .subsections_via_symbols,
697 // then we need to emit *something* to the function body to prevent the
698 // labels from collapsing together. Just emit a noop.
699 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
701 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
702 if (Noop.getOpcode()) {
703 OutStreamer.AddComment("avoids zero-length function");
704 OutStreamer.EmitInstruction(Noop);
705 } else // Target not mc-ized yet.
706 OutStreamer.EmitRawText(StringRef("\tnop\n"));
709 // Emit target-specific gunk after the function body.
710 EmitFunctionBodyEnd();
712 // If the target wants a .size directive for the size of the function, emit
714 if (MAI->hasDotTypeDotSizeDirective()) {
715 // Create a symbol for the end of function, so we can get the size as
716 // difference between the function label and the temp label.
717 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
718 OutStreamer.EmitLabel(FnEndLabel);
720 const MCExpr *SizeExp =
721 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
722 MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
724 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
727 // Emit post-function debug information.
729 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
733 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
738 // Print out jump tables referenced by the function.
741 OutStreamer.AddBlankLine();
744 /// getDebugValueLocation - Get location information encoded by DBG_VALUE
746 MachineLocation AsmPrinter::
747 getDebugValueLocation(const MachineInstr *MI) const {
748 // Target specific DBG_VALUE instructions are handled by each target.
749 return MachineLocation();
752 /// EmitDwarfRegOp - Emit dwarf register operation.
753 void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc,
754 unsigned ExtraExprSize) const {
755 const TargetRegisterInfo *RI = TM.getRegisterInfo();
756 unsigned Reg = RI->getDwarfRegNum(MLoc.getReg(), false);
757 if (int Offset = MLoc.getOffset()) {
758 // If the value is at a certain offset from frame register then
760 unsigned OffsetSize = Offset ? MCAsmInfo::getSLEB128Size(Offset) : 1;
761 OutStreamer.AddComment("Loc expr size");
762 EmitInt16(1 + OffsetSize + ExtraExprSize);
763 OutStreamer.AddComment(
764 dwarf::OperationEncodingString(dwarf::DW_OP_fbreg));
765 EmitInt8(dwarf::DW_OP_fbreg);
766 OutStreamer.AddComment("Offset");
770 OutStreamer.AddComment("Loc expr size");
772 OutStreamer.AddComment(
773 dwarf::OperationEncodingString(dwarf::DW_OP_reg0 + Reg));
774 EmitInt8(dwarf::DW_OP_reg0 + Reg);
776 OutStreamer.AddComment("Loc expr size");
777 EmitInt16(1 + MCAsmInfo::getULEB128Size(Reg) + ExtraExprSize);
778 OutStreamer.AddComment(
779 dwarf::OperationEncodingString(dwarf::DW_OP_regx));
780 EmitInt8(dwarf::DW_OP_regx);
781 OutStreamer.AddComment(Twine(Reg));
787 bool AsmPrinter::doFinalization(Module &M) {
788 // Emit global variables.
789 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
791 EmitGlobalVariable(I);
793 // Emit visibility info for declarations
794 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
795 const Function &F = *I;
796 if (!F.isDeclaration())
798 GlobalValue::VisibilityTypes V = F.getVisibility();
799 if (V == GlobalValue::DefaultVisibility)
802 MCSymbol *Name = Mang->getSymbol(&F);
803 EmitVisibility(Name, V, false);
806 // Finalize debug and EH information.
809 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
816 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
822 // If the target wants to know about weak references, print them all.
823 if (MAI->getWeakRefDirective()) {
824 // FIXME: This is not lazy, it would be nice to only print weak references
825 // to stuff that is actually used. Note that doing so would require targets
826 // to notice uses in operands (due to constant exprs etc). This should
827 // happen with the MC stuff eventually.
829 // Print out module-level global variables here.
830 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
832 if (!I->hasExternalWeakLinkage()) continue;
833 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
836 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
837 if (!I->hasExternalWeakLinkage()) continue;
838 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
842 if (MAI->hasSetDirective()) {
843 OutStreamer.AddBlankLine();
844 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
846 MCSymbol *Name = Mang->getSymbol(I);
848 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
849 MCSymbol *Target = Mang->getSymbol(GV);
851 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
852 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
853 else if (I->hasWeakLinkage())
854 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
856 assert(I->hasLocalLinkage() && "Invalid alias linkage");
858 EmitVisibility(Name, I->getVisibility());
860 // Emit the directives as assignments aka .set:
861 OutStreamer.EmitAssignment(Name,
862 MCSymbolRefExpr::Create(Target, OutContext));
866 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
867 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
868 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
869 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
870 MP->finishAssembly(*this);
872 // If we don't have any trampolines, then we don't require stack memory
873 // to be executable. Some targets have a directive to declare this.
874 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
875 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
876 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
877 OutStreamer.SwitchSection(S);
879 // Allow the target to emit any magic that it wants at the end of the file,
880 // after everything else has gone out.
883 delete Mang; Mang = 0;
886 OutStreamer.Finish();
890 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
892 // Get the function symbol.
893 CurrentFnSym = Mang->getSymbol(MF.getFunction());
896 LI = &getAnalysis<MachineLoopInfo>();
900 // SectionCPs - Keep track the alignment, constpool entries per Section.
904 SmallVector<unsigned, 4> CPEs;
905 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
909 /// EmitConstantPool - Print to the current output stream assembly
910 /// representations of the constants in the constant pool MCP. This is
911 /// used to print out constants which have been "spilled to memory" by
912 /// the code generator.
914 void AsmPrinter::EmitConstantPool() {
915 const MachineConstantPool *MCP = MF->getConstantPool();
916 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
917 if (CP.empty()) return;
919 // Calculate sections for constant pool entries. We collect entries to go into
920 // the same section together to reduce amount of section switch statements.
921 SmallVector<SectionCPs, 4> CPSections;
922 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
923 const MachineConstantPoolEntry &CPE = CP[i];
924 unsigned Align = CPE.getAlignment();
927 switch (CPE.getRelocationInfo()) {
928 default: llvm_unreachable("Unknown section kind");
929 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
931 Kind = SectionKind::getReadOnlyWithRelLocal();
934 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
935 case 4: Kind = SectionKind::getMergeableConst4(); break;
936 case 8: Kind = SectionKind::getMergeableConst8(); break;
937 case 16: Kind = SectionKind::getMergeableConst16();break;
938 default: Kind = SectionKind::getMergeableConst(); break;
942 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
944 // The number of sections are small, just do a linear search from the
945 // last section to the first.
947 unsigned SecIdx = CPSections.size();
948 while (SecIdx != 0) {
949 if (CPSections[--SecIdx].S == S) {
955 SecIdx = CPSections.size();
956 CPSections.push_back(SectionCPs(S, Align));
959 if (Align > CPSections[SecIdx].Alignment)
960 CPSections[SecIdx].Alignment = Align;
961 CPSections[SecIdx].CPEs.push_back(i);
964 // Now print stuff into the calculated sections.
965 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
966 OutStreamer.SwitchSection(CPSections[i].S);
967 EmitAlignment(Log2_32(CPSections[i].Alignment));
970 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
971 unsigned CPI = CPSections[i].CPEs[j];
972 MachineConstantPoolEntry CPE = CP[CPI];
974 // Emit inter-object padding for alignment.
975 unsigned AlignMask = CPE.getAlignment() - 1;
976 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
977 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
979 const Type *Ty = CPE.getType();
980 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
981 OutStreamer.EmitLabel(GetCPISymbol(CPI));
983 if (CPE.isMachineConstantPoolEntry())
984 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
986 EmitGlobalConstant(CPE.Val.ConstVal);
991 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
992 /// by the current function to the current output stream.
994 void AsmPrinter::EmitJumpTableInfo() {
995 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
996 if (MJTI == 0) return;
997 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
998 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
999 if (JT.empty()) return;
1001 // Pick the directive to use to print the jump table entries, and switch to
1002 // the appropriate section.
1003 const Function *F = MF->getFunction();
1004 bool JTInDiffSection = false;
1005 if (// In PIC mode, we need to emit the jump table to the same section as the
1006 // function body itself, otherwise the label differences won't make sense.
1007 // FIXME: Need a better predicate for this: what about custom entries?
1008 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
1009 // We should also do if the section name is NULL or function is declared
1010 // in discardable section
1011 // FIXME: this isn't the right predicate, should be based on the MCSection
1012 // for the function.
1013 F->isWeakForLinker()) {
1014 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
1016 // Otherwise, drop it in the readonly section.
1017 const MCSection *ReadOnlySection =
1018 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
1019 OutStreamer.SwitchSection(ReadOnlySection);
1020 JTInDiffSection = true;
1023 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
1025 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1026 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1028 // If this jump table was deleted, ignore it.
1029 if (JTBBs.empty()) continue;
1031 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
1032 // .set directive for each unique entry. This reduces the number of
1033 // relocations the assembler will generate for the jump table.
1034 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1035 MAI->hasSetDirective()) {
1036 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1037 const TargetLowering *TLI = TM.getTargetLowering();
1038 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1039 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1040 const MachineBasicBlock *MBB = JTBBs[ii];
1041 if (!EmittedSets.insert(MBB)) continue;
1043 // .set LJTSet, LBB32-base
1045 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1046 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1047 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
1051 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1052 // before each jump table. The first label is never referenced, but tells
1053 // the assembler and linker the extents of the jump table object. The
1054 // second label is actually referenced by the code.
1055 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
1056 // FIXME: This doesn't have to have any specific name, just any randomly
1057 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1058 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
1060 OutStreamer.EmitLabel(GetJTISymbol(JTI));
1062 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1063 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1067 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1069 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1070 const MachineBasicBlock *MBB,
1071 unsigned UID) const {
1072 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1073 const MCExpr *Value = 0;
1074 switch (MJTI->getEntryKind()) {
1075 case MachineJumpTableInfo::EK_Inline:
1076 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
1077 case MachineJumpTableInfo::EK_Custom32:
1078 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1081 case MachineJumpTableInfo::EK_BlockAddress:
1082 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1084 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1086 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1087 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1088 // with a relocation as gp-relative, e.g.:
1090 MCSymbol *MBBSym = MBB->getSymbol();
1091 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1095 case MachineJumpTableInfo::EK_LabelDifference32: {
1096 // EK_LabelDifference32 - Each entry is the address of the block minus
1097 // the address of the jump table. This is used for PIC jump tables where
1098 // gprel32 is not supported. e.g.:
1099 // .word LBB123 - LJTI1_2
1100 // If the .set directive is supported, this is emitted as:
1101 // .set L4_5_set_123, LBB123 - LJTI1_2
1102 // .word L4_5_set_123
1104 // If we have emitted set directives for the jump table entries, print
1105 // them rather than the entries themselves. If we're emitting PIC, then
1106 // emit the table entries as differences between two text section labels.
1107 if (MAI->hasSetDirective()) {
1108 // If we used .set, reference the .set's symbol.
1109 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1113 // Otherwise, use the difference as the jump table entry.
1114 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1115 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1116 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1121 assert(Value && "Unknown entry kind!");
1123 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
1124 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
1128 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1129 /// special global used by LLVM. If so, emit it and return true, otherwise
1130 /// do nothing and return false.
1131 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1132 if (GV->getName() == "llvm.used") {
1133 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1134 EmitLLVMUsedList(GV->getInitializer());
1138 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1139 if (GV->getSection() == "llvm.metadata" ||
1140 GV->hasAvailableExternallyLinkage())
1143 if (!GV->hasAppendingLinkage()) return false;
1145 assert(GV->hasInitializer() && "Not a special LLVM global!");
1147 const TargetData *TD = TM.getTargetData();
1148 unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1149 if (GV->getName() == "llvm.global_ctors") {
1150 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1151 EmitAlignment(Align);
1152 EmitXXStructorList(GV->getInitializer());
1154 if (TM.getRelocationModel() == Reloc::Static &&
1155 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1156 StringRef Sym(".constructors_used");
1157 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1163 if (GV->getName() == "llvm.global_dtors") {
1164 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1165 EmitAlignment(Align);
1166 EmitXXStructorList(GV->getInitializer());
1168 if (TM.getRelocationModel() == Reloc::Static &&
1169 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1170 StringRef Sym(".destructors_used");
1171 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1180 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1181 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1182 /// is true, as being used with this directive.
1183 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1184 // Should be an array of 'i8*'.
1185 ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1186 if (InitList == 0) return;
1188 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1189 const GlobalValue *GV =
1190 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1191 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1192 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1196 /// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
1197 /// function pointers, ignoring the init priority.
1198 void AsmPrinter::EmitXXStructorList(Constant *List) {
1199 // Should be an array of '{ int, void ()* }' structs. The first value is the
1200 // init priority, which we ignore.
1201 if (!isa<ConstantArray>(List)) return;
1202 ConstantArray *InitList = cast<ConstantArray>(List);
1203 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1204 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1205 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
1207 if (CS->getOperand(1)->isNullValue())
1208 return; // Found a null terminator, exit printing.
1209 // Emit the function pointer.
1210 EmitGlobalConstant(CS->getOperand(1));
1214 //===--------------------------------------------------------------------===//
1215 // Emission and print routines
1218 /// EmitInt8 - Emit a byte directive and value.
1220 void AsmPrinter::EmitInt8(int Value) const {
1221 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1224 /// EmitInt16 - Emit a short directive and value.
1226 void AsmPrinter::EmitInt16(int Value) const {
1227 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1230 /// EmitInt32 - Emit a long directive and value.
1232 void AsmPrinter::EmitInt32(int Value) const {
1233 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1236 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1237 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1238 /// labels. This implicitly uses .set if it is available.
1239 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1240 unsigned Size) const {
1241 // Get the Hi-Lo expression.
1242 const MCExpr *Diff =
1243 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1244 MCSymbolRefExpr::Create(Lo, OutContext),
1247 if (!MAI->hasSetDirective()) {
1248 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1252 // Otherwise, emit with .set (aka assignment).
1253 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1254 OutStreamer.EmitAssignment(SetLabel, Diff);
1255 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1258 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1259 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1260 /// specify the labels. This implicitly uses .set if it is available.
1261 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1262 const MCSymbol *Lo, unsigned Size)
1265 // Emit Hi+Offset - Lo
1266 // Get the Hi+Offset expression.
1267 const MCExpr *Plus =
1268 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1269 MCConstantExpr::Create(Offset, OutContext),
1272 // Get the Hi+Offset-Lo expression.
1273 const MCExpr *Diff =
1274 MCBinaryExpr::CreateSub(Plus,
1275 MCSymbolRefExpr::Create(Lo, OutContext),
1278 if (!MAI->hasSetDirective())
1279 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1281 // Otherwise, emit with .set (aka assignment).
1282 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1283 OutStreamer.EmitAssignment(SetLabel, Diff);
1284 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1288 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1289 /// where the size in bytes of the directive is specified by Size and Label
1290 /// specifies the label. This implicitly uses .set if it is available.
1291 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1295 // Emit Label+Offset
1296 const MCExpr *Plus =
1297 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Label, OutContext),
1298 MCConstantExpr::Create(Offset, OutContext),
1301 OutStreamer.EmitValue(Plus, 4, 0/*AddrSpace*/);
1305 //===----------------------------------------------------------------------===//
1307 // EmitAlignment - Emit an alignment directive to the specified power of
1308 // two boundary. For example, if you pass in 3 here, you will get an 8
1309 // byte alignment. If a global value is specified, and if that global has
1310 // an explicit alignment requested, it will override the alignment request
1311 // if required for correctness.
1313 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1314 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
1316 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1318 if (getCurrentSection()->getKind().isText())
1319 OutStreamer.EmitCodeAlignment(1 << NumBits);
1321 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1324 //===----------------------------------------------------------------------===//
1325 // Constant emission.
1326 //===----------------------------------------------------------------------===//
1328 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1330 static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1331 MCContext &Ctx = AP.OutContext;
1333 if (CV->isNullValue() || isa<UndefValue>(CV))
1334 return MCConstantExpr::Create(0, Ctx);
1336 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1337 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1339 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1340 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1342 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1343 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1345 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1347 llvm_unreachable("Unknown constant value to lower!");
1348 return MCConstantExpr::Create(0, Ctx);
1351 switch (CE->getOpcode()) {
1353 // If the code isn't optimized, there may be outstanding folding
1354 // opportunities. Attempt to fold the expression using TargetData as a
1355 // last resort before giving up.
1357 ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1359 return LowerConstant(C, AP);
1361 // Otherwise report the problem to the user.
1364 raw_string_ostream OS(S);
1365 OS << "Unsupported expression in static initializer: ";
1366 WriteAsOperand(OS, CE, /*PrintType=*/false,
1367 !AP.MF ? 0 : AP.MF->getFunction()->getParent());
1368 report_fatal_error(OS.str());
1370 return MCConstantExpr::Create(0, Ctx);
1371 case Instruction::GetElementPtr: {
1372 const TargetData &TD = *AP.TM.getTargetData();
1373 // Generate a symbolic expression for the byte address
1374 const Constant *PtrVal = CE->getOperand(0);
1375 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1376 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1379 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1383 // Truncate/sext the offset to the pointer size.
1384 if (TD.getPointerSizeInBits() != 64) {
1385 int SExtAmount = 64-TD.getPointerSizeInBits();
1386 Offset = (Offset << SExtAmount) >> SExtAmount;
1389 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1393 case Instruction::Trunc:
1394 // We emit the value and depend on the assembler to truncate the generated
1395 // expression properly. This is important for differences between
1396 // blockaddress labels. Since the two labels are in the same function, it
1397 // is reasonable to treat their delta as a 32-bit value.
1399 case Instruction::BitCast:
1400 return LowerConstant(CE->getOperand(0), AP);
1402 case Instruction::IntToPtr: {
1403 const TargetData &TD = *AP.TM.getTargetData();
1404 // Handle casts to pointers by changing them into casts to the appropriate
1405 // integer type. This promotes constant folding and simplifies this code.
1406 Constant *Op = CE->getOperand(0);
1407 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1409 return LowerConstant(Op, AP);
1412 case Instruction::PtrToInt: {
1413 const TargetData &TD = *AP.TM.getTargetData();
1414 // Support only foldable casts to/from pointers that can be eliminated by
1415 // changing the pointer to the appropriately sized integer type.
1416 Constant *Op = CE->getOperand(0);
1417 const Type *Ty = CE->getType();
1419 const MCExpr *OpExpr = LowerConstant(Op, AP);
1421 // We can emit the pointer value into this slot if the slot is an
1422 // integer slot equal to the size of the pointer.
1423 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1426 // Otherwise the pointer is smaller than the resultant integer, mask off
1427 // the high bits so we are sure to get a proper truncation if the input is
1429 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1430 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1431 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1434 // The MC library also has a right-shift operator, but it isn't consistently
1435 // signed or unsigned between different targets.
1436 case Instruction::Add:
1437 case Instruction::Sub:
1438 case Instruction::Mul:
1439 case Instruction::SDiv:
1440 case Instruction::SRem:
1441 case Instruction::Shl:
1442 case Instruction::And:
1443 case Instruction::Or:
1444 case Instruction::Xor: {
1445 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1446 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1447 switch (CE->getOpcode()) {
1448 default: llvm_unreachable("Unknown binary operator constant cast expr");
1449 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1450 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1451 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1452 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1453 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1454 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1455 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1456 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1457 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1463 static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1466 static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1468 if (AddrSpace != 0 || !CA->isString()) {
1469 // Not a string. Print the values in successive locations
1470 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1471 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1475 // Otherwise, it can be emitted as .ascii.
1476 SmallVector<char, 128> TmpVec;
1477 TmpVec.reserve(CA->getNumOperands());
1478 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1479 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1481 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1484 static void EmitGlobalConstantVector(const ConstantVector *CV,
1485 unsigned AddrSpace, AsmPrinter &AP) {
1486 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1487 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1490 static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1491 unsigned AddrSpace, AsmPrinter &AP) {
1492 // Print the fields in successive locations. Pad to align if needed!
1493 const TargetData *TD = AP.TM.getTargetData();
1494 unsigned Size = TD->getTypeAllocSize(CS->getType());
1495 const StructLayout *Layout = TD->getStructLayout(CS->getType());
1496 uint64_t SizeSoFar = 0;
1497 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1498 const Constant *Field = CS->getOperand(i);
1500 // Check if padding is needed and insert one or more 0s.
1501 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1502 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1503 - Layout->getElementOffset(i)) - FieldSize;
1504 SizeSoFar += FieldSize + PadSize;
1506 // Now print the actual field value.
1507 EmitGlobalConstantImpl(Field, AddrSpace, AP);
1509 // Insert padding - this may include padding to increase the size of the
1510 // current field up to the ABI size (if the struct is not packed) as well
1511 // as padding to ensure that the next field starts at the right offset.
1512 AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1514 assert(SizeSoFar == Layout->getSizeInBytes() &&
1515 "Layout of constant struct may be incorrect!");
1518 static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1520 // FP Constants are printed as integer constants to avoid losing
1522 if (CFP->getType()->isDoubleTy()) {
1523 if (AP.isVerbose()) {
1524 double Val = CFP->getValueAPF().convertToDouble();
1525 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1528 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1529 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1533 if (CFP->getType()->isFloatTy()) {
1534 if (AP.isVerbose()) {
1535 float Val = CFP->getValueAPF().convertToFloat();
1536 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1538 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1539 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1543 if (CFP->getType()->isX86_FP80Ty()) {
1544 // all long double variants are printed as hex
1545 // API needed to prevent premature destruction
1546 APInt API = CFP->getValueAPF().bitcastToAPInt();
1547 const uint64_t *p = API.getRawData();
1548 if (AP.isVerbose()) {
1549 // Convert to double so we can print the approximate val as a comment.
1550 APFloat DoubleVal = CFP->getValueAPF();
1552 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1554 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1555 << DoubleVal.convertToDouble() << '\n';
1558 if (AP.TM.getTargetData()->isBigEndian()) {
1559 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1560 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1562 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1563 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1566 // Emit the tail padding for the long double.
1567 const TargetData &TD = *AP.TM.getTargetData();
1568 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1569 TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1573 assert(CFP->getType()->isPPC_FP128Ty() &&
1574 "Floating point constant type not handled");
1575 // All long double variants are printed as hex
1576 // API needed to prevent premature destruction.
1577 APInt API = CFP->getValueAPF().bitcastToAPInt();
1578 const uint64_t *p = API.getRawData();
1579 if (AP.TM.getTargetData()->isBigEndian()) {
1580 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1581 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1583 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1584 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1588 static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1589 unsigned AddrSpace, AsmPrinter &AP) {
1590 const TargetData *TD = AP.TM.getTargetData();
1591 unsigned BitWidth = CI->getBitWidth();
1592 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1594 // We don't expect assemblers to support integer data directives
1595 // for more than 64 bits, so we emit the data in at most 64-bit
1596 // quantities at a time.
1597 const uint64_t *RawData = CI->getValue().getRawData();
1598 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1599 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1600 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1604 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1606 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1607 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1608 return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1611 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1612 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1619 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1620 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1623 EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1628 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1629 return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1631 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1632 return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1634 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1635 return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1637 if (isa<ConstantPointerNull>(CV)) {
1638 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1639 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1643 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1644 return EmitGlobalConstantVector(V, AddrSpace, AP);
1646 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
1647 // thread the streamer with EmitValue.
1648 AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1649 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1653 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1654 void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1655 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1657 EmitGlobalConstantImpl(CV, AddrSpace, *this);
1658 else if (MAI->hasSubsectionsViaSymbols()) {
1659 // If the global has zero size, emit a single byte so that two labels don't
1660 // look like they are at the same location.
1661 OutStreamer.EmitIntValue(0, 1, AddrSpace);
1665 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1666 // Target doesn't support this yet!
1667 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1670 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1672 OS << '+' << Offset;
1673 else if (Offset < 0)
1677 //===----------------------------------------------------------------------===//
1678 // Symbol Lowering Routines.
1679 //===----------------------------------------------------------------------===//
1681 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1682 /// temporary label with the specified stem and unique ID.
1683 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1684 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1688 /// GetTempSymbol - Return an assembler temporary label with the specified
1690 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1691 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1696 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1697 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1700 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1701 return MMI->getAddrLabelSymbol(BB);
1704 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
1705 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1706 return OutContext.GetOrCreateSymbol
1707 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1708 + "_" + Twine(CPID));
1711 /// GetJTISymbol - Return the symbol for the specified jump table entry.
1712 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1713 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1716 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
1717 /// FIXME: privatize to AsmPrinter.
1718 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1719 return OutContext.GetOrCreateSymbol
1720 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1721 Twine(UID) + "_set_" + Twine(MBBID));
1724 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1725 /// global value name as its base, with the specified suffix, and where the
1726 /// symbol is forced to have private linkage if ForcePrivate is true.
1727 MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1729 bool ForcePrivate) const {
1730 SmallString<60> NameStr;
1731 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1732 NameStr.append(Suffix.begin(), Suffix.end());
1733 return OutContext.GetOrCreateSymbol(NameStr.str());
1736 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1738 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1739 SmallString<60> NameStr;
1740 Mang->getNameWithPrefix(NameStr, Sym);
1741 return OutContext.GetOrCreateSymbol(NameStr.str());
1746 /// PrintParentLoopComment - Print comments about parent loops of this one.
1747 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1748 unsigned FunctionNumber) {
1749 if (Loop == 0) return;
1750 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1751 OS.indent(Loop->getLoopDepth()*2)
1752 << "Parent Loop BB" << FunctionNumber << "_"
1753 << Loop->getHeader()->getNumber()
1754 << " Depth=" << Loop->getLoopDepth() << '\n';
1758 /// PrintChildLoopComment - Print comments about child loops within
1759 /// the loop for this basic block, with nesting.
1760 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1761 unsigned FunctionNumber) {
1762 // Add child loop information
1763 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1764 OS.indent((*CL)->getLoopDepth()*2)
1765 << "Child Loop BB" << FunctionNumber << "_"
1766 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1768 PrintChildLoopComment(OS, *CL, FunctionNumber);
1772 /// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1773 static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1774 const MachineLoopInfo *LI,
1775 const AsmPrinter &AP) {
1776 // Add loop depth information
1777 const MachineLoop *Loop = LI->getLoopFor(&MBB);
1778 if (Loop == 0) return;
1780 MachineBasicBlock *Header = Loop->getHeader();
1781 assert(Header && "No header for loop");
1783 // If this block is not a loop header, just print out what is the loop header
1785 if (Header != &MBB) {
1786 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
1787 Twine(AP.getFunctionNumber())+"_" +
1788 Twine(Loop->getHeader()->getNumber())+
1789 " Depth="+Twine(Loop->getLoopDepth()));
1793 // Otherwise, it is a loop header. Print out information about child and
1795 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1797 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1800 OS.indent(Loop->getLoopDepth()*2-2);
1805 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1807 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1811 /// EmitBasicBlockStart - This method prints the label for the specified
1812 /// MachineBasicBlock, an alignment (if present) and a comment describing
1813 /// it if appropriate.
1814 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1815 // Emit an alignment directive for this block, if needed.
1816 if (unsigned Align = MBB->getAlignment())
1817 EmitAlignment(Log2_32(Align));
1819 // If the block has its address taken, emit any labels that were used to
1820 // reference the block. It is possible that there is more than one label
1821 // here, because multiple LLVM BB's may have been RAUW'd to this block after
1822 // the references were generated.
1823 if (MBB->hasAddressTaken()) {
1824 const BasicBlock *BB = MBB->getBasicBlock();
1826 OutStreamer.AddComment("Block address taken");
1828 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1830 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1831 OutStreamer.EmitLabel(Syms[i]);
1834 // Print the main label for the block.
1835 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1836 if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1837 if (const BasicBlock *BB = MBB->getBasicBlock())
1839 OutStreamer.AddComment("%" + BB->getName());
1841 EmitBasicBlockLoopComments(*MBB, LI, *this);
1843 // NOTE: Want this comment at start of line, don't emit with AddComment.
1844 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1845 Twine(MBB->getNumber()) + ":");
1849 if (const BasicBlock *BB = MBB->getBasicBlock())
1851 OutStreamer.AddComment("%" + BB->getName());
1852 EmitBasicBlockLoopComments(*MBB, LI, *this);
1855 OutStreamer.EmitLabel(MBB->getSymbol());
1859 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
1860 bool IsDefinition) const {
1861 MCSymbolAttr Attr = MCSA_Invalid;
1863 switch (Visibility) {
1865 case GlobalValue::HiddenVisibility:
1867 Attr = MAI->getHiddenVisibilityAttr();
1869 Attr = MAI->getHiddenDeclarationVisibilityAttr();
1871 case GlobalValue::ProtectedVisibility:
1872 Attr = MAI->getProtectedVisibilityAttr();
1876 if (Attr != MCSA_Invalid)
1877 OutStreamer.EmitSymbolAttribute(Sym, Attr);
1880 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
1881 /// exactly one predecessor and the control transfer mechanism between
1882 /// the predecessor and this block is a fall-through.
1884 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1885 // If this is a landing pad, it isn't a fall through. If it has no preds,
1886 // then nothing falls through to it.
1887 if (MBB->isLandingPad() || MBB->pred_empty())
1890 // If there isn't exactly one predecessor, it can't be a fall through.
1891 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1893 if (PI2 != MBB->pred_end())
1896 // The predecessor has to be immediately before this block.
1897 const MachineBasicBlock *Pred = *PI;
1899 if (!Pred->isLayoutSuccessor(MBB))
1902 // If the block is completely empty, then it definitely does fall through.
1906 // Otherwise, check the last instruction.
1907 const MachineInstr &LastInst = Pred->back();
1908 return !LastInst.getDesc().isBarrier();
1913 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1914 if (!S->usesMetadata())
1917 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1918 gcp_map_type::iterator GCPI = GCMap.find(S);
1919 if (GCPI != GCMap.end())
1920 return GCPI->second;
1922 const char *Name = S->getName().c_str();
1924 for (GCMetadataPrinterRegistry::iterator
1925 I = GCMetadataPrinterRegistry::begin(),
1926 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1927 if (strcmp(Name, I->getName()) == 0) {
1928 GCMetadataPrinter *GMP = I->instantiate();
1930 GCMap.insert(std::make_pair(S, GMP));
1934 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));