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.
293 WriteAsOperand(OutStreamer.GetCommentOS(), GV,
294 /*PrintType=*/false, GV->getParent());
295 OutStreamer.GetCommentOS() << '\n';
298 // Handle common symbols.
299 if (GVKind.isCommon()) {
300 unsigned Align = 1 << AlignLog;
301 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
305 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
309 // Handle local BSS symbols.
310 if (MAI->hasMachoZeroFillDirective()) {
311 const MCSection *TheSection =
312 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
313 // .zerofill __DATA, __bss, _foo, 400, 5
314 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
318 if (MAI->hasLCOMMDirective()) {
320 OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
324 unsigned Align = 1 << AlignLog;
325 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
329 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
331 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
335 const MCSection *TheSection =
336 getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
338 // Handle the zerofill directive on darwin, which is a special form of BSS
340 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
341 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
344 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
345 // .zerofill __DATA, __common, _foo, 400, 5
346 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
350 // Handle thread local data for mach-o which requires us to output an
351 // additional structure of data and mangle the original symbol so that we
352 // can reference it later.
354 // TODO: This should become an "emit thread local global" method on TLOF.
355 // All of this macho specific stuff should be sunk down into TLOFMachO and
356 // stuff like "TLSExtraDataSection" should no longer be part of the parent
357 // TLOF class. This will also make it more obvious that stuff like
358 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
360 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
361 // Emit the .tbss symbol
363 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
365 if (GVKind.isThreadBSS())
366 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
367 else if (GVKind.isThreadData()) {
368 OutStreamer.SwitchSection(TheSection);
370 EmitAlignment(AlignLog, GV);
371 OutStreamer.EmitLabel(MangSym);
373 EmitGlobalConstant(GV->getInitializer());
376 OutStreamer.AddBlankLine();
378 // Emit the variable struct for the runtime.
379 const MCSection *TLVSect
380 = getObjFileLowering().getTLSExtraDataSection();
382 OutStreamer.SwitchSection(TLVSect);
383 // Emit the linkage here.
384 EmitLinkage(GV->getLinkage(), GVSym);
385 OutStreamer.EmitLabel(GVSym);
387 // Three pointers in size:
388 // - __tlv_bootstrap - used to make sure support exists
389 // - spare pointer, used when mapped by the runtime
390 // - pointer to mangled symbol above with initializer
391 unsigned PtrSize = TD->getPointerSizeInBits()/8;
392 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
394 OutStreamer.EmitIntValue(0, PtrSize, 0);
395 OutStreamer.EmitSymbolValue(MangSym, PtrSize, 0);
397 OutStreamer.AddBlankLine();
401 OutStreamer.SwitchSection(TheSection);
403 EmitLinkage(GV->getLinkage(), GVSym);
404 EmitAlignment(AlignLog, GV);
406 OutStreamer.EmitLabel(GVSym);
408 EmitGlobalConstant(GV->getInitializer());
410 if (MAI->hasDotTypeDotSizeDirective())
412 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
414 OutStreamer.AddBlankLine();
417 /// EmitFunctionHeader - This method emits the header for the current
419 void AsmPrinter::EmitFunctionHeader() {
420 // Print out constants referenced by the function
423 // Print the 'header' of function.
424 const Function *F = MF->getFunction();
426 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
427 EmitVisibility(CurrentFnSym, F->getVisibility());
429 EmitLinkage(F->getLinkage(), CurrentFnSym);
430 EmitAlignment(MF->getAlignment(), F);
432 if (MAI->hasDotTypeDotSizeDirective())
433 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
436 WriteAsOperand(OutStreamer.GetCommentOS(), F,
437 /*PrintType=*/false, F->getParent());
438 OutStreamer.GetCommentOS() << '\n';
441 // Emit the CurrentFnSym. This is a virtual function to allow targets to
442 // do their wild and crazy things as required.
443 EmitFunctionEntryLabel();
445 // If the function had address-taken blocks that got deleted, then we have
446 // references to the dangling symbols. Emit them at the start of the function
447 // so that we don't get references to undefined symbols.
448 std::vector<MCSymbol*> DeadBlockSyms;
449 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
450 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
451 OutStreamer.AddComment("Address taken block that was later removed");
452 OutStreamer.EmitLabel(DeadBlockSyms[i]);
455 // Add some workaround for linkonce linkage on Cygwin\MinGW.
456 if (MAI->getLinkOnceDirective() != 0 &&
457 (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
458 // FIXME: What is this?
460 OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
461 CurrentFnSym->getName());
462 OutStreamer.EmitLabel(FakeStub);
465 // Emit pre-function debug and/or EH information.
467 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
468 DE->BeginFunction(MF);
471 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
472 DD->beginFunction(MF);
476 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
477 /// function. This can be overridden by targets as required to do custom stuff.
478 void AsmPrinter::EmitFunctionEntryLabel() {
479 // The function label could have already been emitted if two symbols end up
480 // conflicting due to asm renaming. Detect this and emit an error.
481 if (CurrentFnSym->isUndefined())
482 return OutStreamer.EmitLabel(CurrentFnSym);
484 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
485 "' label emitted multiple times to assembly file");
489 /// EmitComments - Pretty-print comments for instructions.
490 static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
491 const MachineFunction *MF = MI.getParent()->getParent();
492 const TargetMachine &TM = MF->getTarget();
494 // Check for spills and reloads
497 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
499 // We assume a single instruction only has a spill or reload, not
501 const MachineMemOperand *MMO;
502 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
503 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
504 MMO = *MI.memoperands_begin();
505 CommentOS << MMO->getSize() << "-byte Reload\n";
507 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
508 if (FrameInfo->isSpillSlotObjectIndex(FI))
509 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
510 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
511 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
512 MMO = *MI.memoperands_begin();
513 CommentOS << MMO->getSize() << "-byte Spill\n";
515 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
516 if (FrameInfo->isSpillSlotObjectIndex(FI))
517 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
520 // Check for spill-induced copies
521 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
522 CommentOS << " Reload Reuse\n";
525 /// EmitImplicitDef - This method emits the specified machine instruction
526 /// that is an implicit def.
527 static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
528 unsigned RegNo = MI->getOperand(0).getReg();
529 AP.OutStreamer.AddComment(Twine("implicit-def: ") +
530 AP.TM.getRegisterInfo()->getName(RegNo));
531 AP.OutStreamer.AddBlankLine();
534 static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
535 std::string Str = "kill:";
536 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
537 const MachineOperand &Op = MI->getOperand(i);
538 assert(Op.isReg() && "KILL instruction must have only register operands");
540 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
541 Str += (Op.isDef() ? "<def>" : "<kill>");
543 AP.OutStreamer.AddComment(Str);
544 AP.OutStreamer.AddBlankLine();
547 /// EmitDebugValueComment - This method handles the target-independent form
548 /// of DBG_VALUE, returning true if it was able to do so. A false return
549 /// means the target will need to handle MI in EmitInstruction.
550 static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
551 // This code handles only the 3-operand target-independent form.
552 if (MI->getNumOperands() != 3)
555 SmallString<128> Str;
556 raw_svector_ostream OS(Str);
557 OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
559 // cast away const; DIetc do not take const operands for some reason.
560 DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
561 if (V.getContext().isSubprogram())
562 OS << DISubprogram(V.getContext()).getDisplayName() << ":";
563 OS << V.getName() << " <- ";
565 // Register or immediate value. Register 0 means undef.
566 if (MI->getOperand(0).isFPImm()) {
567 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
568 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
569 OS << (double)APF.convertToFloat();
570 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
571 OS << APF.convertToDouble();
573 // There is no good way to print long double. Convert a copy to
574 // double. Ah well, it's only a comment.
576 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
578 OS << "(long double) " << APF.convertToDouble();
580 } else if (MI->getOperand(0).isImm()) {
581 OS << MI->getOperand(0).getImm();
583 assert(MI->getOperand(0).isReg() && "Unknown operand type");
584 if (MI->getOperand(0).getReg() == 0) {
585 // Suppress offset, it is not meaningful here.
587 // NOTE: Want this comment at start of line, don't emit with AddComment.
588 AP.OutStreamer.EmitRawText(OS.str());
591 OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
594 OS << '+' << MI->getOperand(1).getImm();
595 // NOTE: Want this comment at start of line, don't emit with AddComment.
596 AP.OutStreamer.EmitRawText(OS.str());
600 void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
601 MCSymbol *Label = MI.getOperand(0).getMCSymbol();
602 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI) {
603 OutStreamer.EmitLabel(Label);
607 const MachineFunction &MF = *MI.getParent()->getParent();
608 MachineModuleInfo &MMI = MF.getMMI();
609 std::vector<MachineMove> &Moves = MMI.getFrameMoves();
610 const MachineMove *Move = NULL;
611 for (std::vector<MachineMove>::iterator I = Moves.begin(),
612 E = Moves.end(); I != E; ++I) {
613 if (I->getLabel() == Label) {
619 EmitCFIFrameMove(*Move);
622 /// EmitFunctionBody - This method emits the body and trailer for a
624 void AsmPrinter::EmitFunctionBody() {
625 // Emit target-specific gunk before the function body.
626 EmitFunctionBodyStart();
628 bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
630 // Print out code for the function.
631 bool HasAnyRealCode = false;
632 const MachineInstr *LastMI = 0;
633 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
635 // Print a label for the basic block.
636 EmitBasicBlockStart(I);
637 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
641 // Print the assembly for the instruction.
642 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
643 !II->isDebugValue()) {
644 HasAnyRealCode = true;
648 if (ShouldPrintDebugScopes) {
649 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
650 DD->beginInstruction(II);
654 EmitComments(*II, OutStreamer.GetCommentOS());
656 switch (II->getOpcode()) {
657 case TargetOpcode::PROLOG_LABEL:
658 emitPrologLabel(*II);
661 case TargetOpcode::EH_LABEL:
662 case TargetOpcode::GC_LABEL:
663 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
665 case TargetOpcode::INLINEASM:
668 case TargetOpcode::DBG_VALUE:
670 if (!EmitDebugValueComment(II, *this))
674 case TargetOpcode::IMPLICIT_DEF:
675 if (isVerbose()) EmitImplicitDef(II, *this);
677 case TargetOpcode::KILL:
678 if (isVerbose()) EmitKill(II, *this);
685 if (ShouldPrintDebugScopes) {
686 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
687 DD->endInstruction(II);
692 // If the last instruction was a prolog label, then we have a situation where
693 // we emitted a prolog but no function body. This results in the ending prolog
694 // label equaling the end of function label and an invalid "row" in the
695 // FDE. We need to emit a noop in this situation so that the FDE's rows are
697 bool RequiresNoop = LastMI && LastMI->isPrologLabel();
699 // If the function is empty and the object file uses .subsections_via_symbols,
700 // then we need to emit *something* to the function body to prevent the
701 // labels from collapsing together. Just emit a noop.
702 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
704 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
705 if (Noop.getOpcode()) {
706 OutStreamer.AddComment("avoids zero-length function");
707 OutStreamer.EmitInstruction(Noop);
708 } else // Target not mc-ized yet.
709 OutStreamer.EmitRawText(StringRef("\tnop\n"));
712 // Emit target-specific gunk after the function body.
713 EmitFunctionBodyEnd();
715 // If the target wants a .size directive for the size of the function, emit
717 if (MAI->hasDotTypeDotSizeDirective()) {
718 // Create a symbol for the end of function, so we can get the size as
719 // difference between the function label and the temp label.
720 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
721 OutStreamer.EmitLabel(FnEndLabel);
723 const MCExpr *SizeExp =
724 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
725 MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
727 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
730 // Emit post-function debug information.
732 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
736 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
741 // Print out jump tables referenced by the function.
744 OutStreamer.AddBlankLine();
747 /// getDebugValueLocation - Get location information encoded by DBG_VALUE
749 MachineLocation AsmPrinter::
750 getDebugValueLocation(const MachineInstr *MI) const {
751 // Target specific DBG_VALUE instructions are handled by each target.
752 return MachineLocation();
755 /// EmitDwarfRegOp - Emit dwarf register operation.
756 void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
757 const TargetRegisterInfo *RI = TM.getRegisterInfo();
758 unsigned Reg = RI->getDwarfRegNum(MLoc.getReg(), false);
759 if (int Offset = MLoc.getOffset()) {
760 // If the value is at a certain offset from frame register then
762 unsigned OffsetSize = Offset ? MCAsmInfo::getSLEB128Size(Offset) : 1;
763 OutStreamer.AddComment("Loc expr size");
764 EmitInt16(1 + OffsetSize);
765 OutStreamer.AddComment(
766 dwarf::OperationEncodingString(dwarf::DW_OP_fbreg));
767 EmitInt8(dwarf::DW_OP_fbreg);
768 OutStreamer.AddComment("Offset");
772 OutStreamer.AddComment("Loc expr size");
774 OutStreamer.AddComment(
775 dwarf::OperationEncodingString(dwarf::DW_OP_reg0 + Reg));
776 EmitInt8(dwarf::DW_OP_reg0 + Reg);
778 OutStreamer.AddComment("Loc expr size");
779 EmitInt16(1 + MCAsmInfo::getULEB128Size(Reg));
780 OutStreamer.AddComment(
781 dwarf::OperationEncodingString(dwarf::DW_OP_regx));
782 EmitInt8(dwarf::DW_OP_regx);
783 OutStreamer.AddComment(Twine(Reg));
789 bool AsmPrinter::doFinalization(Module &M) {
790 // Emit global variables.
791 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
793 EmitGlobalVariable(I);
795 // Emit visibility info for declarations
796 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
797 const Function &F = *I;
798 if (!F.isDeclaration())
800 GlobalValue::VisibilityTypes V = F.getVisibility();
801 if (V == GlobalValue::DefaultVisibility)
804 MCSymbol *Name = Mang->getSymbol(&F);
805 EmitVisibility(Name, V, false);
808 // Finalize debug and EH information.
811 NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
818 NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
824 // If the target wants to know about weak references, print them all.
825 if (MAI->getWeakRefDirective()) {
826 // FIXME: This is not lazy, it would be nice to only print weak references
827 // to stuff that is actually used. Note that doing so would require targets
828 // to notice uses in operands (due to constant exprs etc). This should
829 // happen with the MC stuff eventually.
831 // Print out module-level global variables here.
832 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
834 if (!I->hasExternalWeakLinkage()) continue;
835 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
838 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
839 if (!I->hasExternalWeakLinkage()) continue;
840 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
844 if (MAI->hasSetDirective()) {
845 OutStreamer.AddBlankLine();
846 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
848 MCSymbol *Name = Mang->getSymbol(I);
850 const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
851 MCSymbol *Target = Mang->getSymbol(GV);
853 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
854 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
855 else if (I->hasWeakLinkage())
856 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
858 assert(I->hasLocalLinkage() && "Invalid alias linkage");
860 EmitVisibility(Name, I->getVisibility());
862 // Emit the directives as assignments aka .set:
863 OutStreamer.EmitAssignment(Name,
864 MCSymbolRefExpr::Create(Target, OutContext));
868 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
869 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
870 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
871 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
872 MP->finishAssembly(*this);
874 // If we don't have any trampolines, then we don't require stack memory
875 // to be executable. Some targets have a directive to declare this.
876 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
877 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
878 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
879 OutStreamer.SwitchSection(S);
881 // Allow the target to emit any magic that it wants at the end of the file,
882 // after everything else has gone out.
885 delete Mang; Mang = 0;
888 OutStreamer.Finish();
892 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
894 // Get the function symbol.
895 CurrentFnSym = Mang->getSymbol(MF.getFunction());
898 LI = &getAnalysis<MachineLoopInfo>();
902 // SectionCPs - Keep track the alignment, constpool entries per Section.
906 SmallVector<unsigned, 4> CPEs;
907 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
911 /// EmitConstantPool - Print to the current output stream assembly
912 /// representations of the constants in the constant pool MCP. This is
913 /// used to print out constants which have been "spilled to memory" by
914 /// the code generator.
916 void AsmPrinter::EmitConstantPool() {
917 const MachineConstantPool *MCP = MF->getConstantPool();
918 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
919 if (CP.empty()) return;
921 // Calculate sections for constant pool entries. We collect entries to go into
922 // the same section together to reduce amount of section switch statements.
923 SmallVector<SectionCPs, 4> CPSections;
924 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
925 const MachineConstantPoolEntry &CPE = CP[i];
926 unsigned Align = CPE.getAlignment();
929 switch (CPE.getRelocationInfo()) {
930 default: llvm_unreachable("Unknown section kind");
931 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
933 Kind = SectionKind::getReadOnlyWithRelLocal();
936 switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
937 case 4: Kind = SectionKind::getMergeableConst4(); break;
938 case 8: Kind = SectionKind::getMergeableConst8(); break;
939 case 16: Kind = SectionKind::getMergeableConst16();break;
940 default: Kind = SectionKind::getMergeableConst(); break;
944 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
946 // The number of sections are small, just do a linear search from the
947 // last section to the first.
949 unsigned SecIdx = CPSections.size();
950 while (SecIdx != 0) {
951 if (CPSections[--SecIdx].S == S) {
957 SecIdx = CPSections.size();
958 CPSections.push_back(SectionCPs(S, Align));
961 if (Align > CPSections[SecIdx].Alignment)
962 CPSections[SecIdx].Alignment = Align;
963 CPSections[SecIdx].CPEs.push_back(i);
966 // Now print stuff into the calculated sections.
967 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
968 OutStreamer.SwitchSection(CPSections[i].S);
969 EmitAlignment(Log2_32(CPSections[i].Alignment));
972 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
973 unsigned CPI = CPSections[i].CPEs[j];
974 MachineConstantPoolEntry CPE = CP[CPI];
976 // Emit inter-object padding for alignment.
977 unsigned AlignMask = CPE.getAlignment() - 1;
978 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
979 OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
981 const Type *Ty = CPE.getType();
982 Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
983 OutStreamer.EmitLabel(GetCPISymbol(CPI));
985 if (CPE.isMachineConstantPoolEntry())
986 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
988 EmitGlobalConstant(CPE.Val.ConstVal);
993 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
994 /// by the current function to the current output stream.
996 void AsmPrinter::EmitJumpTableInfo() {
997 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
998 if (MJTI == 0) return;
999 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1000 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1001 if (JT.empty()) return;
1003 // Pick the directive to use to print the jump table entries, and switch to
1004 // the appropriate section.
1005 const Function *F = MF->getFunction();
1006 bool JTInDiffSection = false;
1007 if (// In PIC mode, we need to emit the jump table to the same section as the
1008 // function body itself, otherwise the label differences won't make sense.
1009 // FIXME: Need a better predicate for this: what about custom entries?
1010 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
1011 // We should also do if the section name is NULL or function is declared
1012 // in discardable section
1013 // FIXME: this isn't the right predicate, should be based on the MCSection
1014 // for the function.
1015 F->isWeakForLinker()) {
1016 OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
1018 // Otherwise, drop it in the readonly section.
1019 const MCSection *ReadOnlySection =
1020 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
1021 OutStreamer.SwitchSection(ReadOnlySection);
1022 JTInDiffSection = true;
1025 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
1027 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1028 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1030 // If this jump table was deleted, ignore it.
1031 if (JTBBs.empty()) continue;
1033 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
1034 // .set directive for each unique entry. This reduces the number of
1035 // relocations the assembler will generate for the jump table.
1036 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1037 MAI->hasSetDirective()) {
1038 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1039 const TargetLowering *TLI = TM.getTargetLowering();
1040 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1041 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1042 const MachineBasicBlock *MBB = JTBBs[ii];
1043 if (!EmittedSets.insert(MBB)) continue;
1045 // .set LJTSet, LBB32-base
1047 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1048 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1049 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
1053 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1054 // before each jump table. The first label is never referenced, but tells
1055 // the assembler and linker the extents of the jump table object. The
1056 // second label is actually referenced by the code.
1057 if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
1058 // FIXME: This doesn't have to have any specific name, just any randomly
1059 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1060 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
1062 OutStreamer.EmitLabel(GetJTISymbol(JTI));
1064 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1065 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1069 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1071 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1072 const MachineBasicBlock *MBB,
1073 unsigned UID) const {
1074 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1075 const MCExpr *Value = 0;
1076 switch (MJTI->getEntryKind()) {
1077 case MachineJumpTableInfo::EK_Inline:
1078 llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
1079 case MachineJumpTableInfo::EK_Custom32:
1080 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1083 case MachineJumpTableInfo::EK_BlockAddress:
1084 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1086 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1088 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1089 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1090 // with a relocation as gp-relative, e.g.:
1092 MCSymbol *MBBSym = MBB->getSymbol();
1093 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1097 case MachineJumpTableInfo::EK_LabelDifference32: {
1098 // EK_LabelDifference32 - Each entry is the address of the block minus
1099 // the address of the jump table. This is used for PIC jump tables where
1100 // gprel32 is not supported. e.g.:
1101 // .word LBB123 - LJTI1_2
1102 // If the .set directive is supported, this is emitted as:
1103 // .set L4_5_set_123, LBB123 - LJTI1_2
1104 // .word L4_5_set_123
1106 // If we have emitted set directives for the jump table entries, print
1107 // them rather than the entries themselves. If we're emitting PIC, then
1108 // emit the table entries as differences between two text section labels.
1109 if (MAI->hasSetDirective()) {
1110 // If we used .set, reference the .set's symbol.
1111 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1115 // Otherwise, use the difference as the jump table entry.
1116 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1117 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1118 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1123 assert(Value && "Unknown entry kind!");
1125 unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
1126 OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
1130 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1131 /// special global used by LLVM. If so, emit it and return true, otherwise
1132 /// do nothing and return false.
1133 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1134 if (GV->getName() == "llvm.used") {
1135 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1136 EmitLLVMUsedList(GV->getInitializer());
1140 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1141 if (GV->getSection() == "llvm.metadata" ||
1142 GV->hasAvailableExternallyLinkage())
1145 if (!GV->hasAppendingLinkage()) return false;
1147 assert(GV->hasInitializer() && "Not a special LLVM global!");
1149 const TargetData *TD = TM.getTargetData();
1150 unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1151 if (GV->getName() == "llvm.global_ctors") {
1152 OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1153 EmitAlignment(Align);
1154 EmitXXStructorList(GV->getInitializer());
1156 if (TM.getRelocationModel() == Reloc::Static &&
1157 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1158 StringRef Sym(".constructors_used");
1159 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1165 if (GV->getName() == "llvm.global_dtors") {
1166 OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1167 EmitAlignment(Align);
1168 EmitXXStructorList(GV->getInitializer());
1170 if (TM.getRelocationModel() == Reloc::Static &&
1171 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1172 StringRef Sym(".destructors_used");
1173 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1182 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1183 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1184 /// is true, as being used with this directive.
1185 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1186 // Should be an array of 'i8*'.
1187 ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1188 if (InitList == 0) return;
1190 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1191 const GlobalValue *GV =
1192 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1193 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1194 OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1198 /// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
1199 /// function pointers, ignoring the init priority.
1200 void AsmPrinter::EmitXXStructorList(Constant *List) {
1201 // Should be an array of '{ int, void ()* }' structs. The first value is the
1202 // init priority, which we ignore.
1203 if (!isa<ConstantArray>(List)) return;
1204 ConstantArray *InitList = cast<ConstantArray>(List);
1205 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1206 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1207 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
1209 if (CS->getOperand(1)->isNullValue())
1210 return; // Found a null terminator, exit printing.
1211 // Emit the function pointer.
1212 EmitGlobalConstant(CS->getOperand(1));
1216 //===--------------------------------------------------------------------===//
1217 // Emission and print routines
1220 /// EmitInt8 - Emit a byte directive and value.
1222 void AsmPrinter::EmitInt8(int Value) const {
1223 OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1226 /// EmitInt16 - Emit a short directive and value.
1228 void AsmPrinter::EmitInt16(int Value) const {
1229 OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1232 /// EmitInt32 - Emit a long directive and value.
1234 void AsmPrinter::EmitInt32(int Value) const {
1235 OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1238 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1239 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1240 /// labels. This implicitly uses .set if it is available.
1241 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1242 unsigned Size) const {
1243 // Get the Hi-Lo expression.
1244 const MCExpr *Diff =
1245 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1246 MCSymbolRefExpr::Create(Lo, OutContext),
1249 if (!MAI->hasSetDirective()) {
1250 OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1254 // Otherwise, emit with .set (aka assignment).
1255 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1256 OutStreamer.EmitAssignment(SetLabel, Diff);
1257 OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1260 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1261 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1262 /// specify the labels. This implicitly uses .set if it is available.
1263 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1264 const MCSymbol *Lo, unsigned Size)
1267 // Emit Hi+Offset - Lo
1268 // Get the Hi+Offset expression.
1269 const MCExpr *Plus =
1270 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1271 MCConstantExpr::Create(Offset, OutContext),
1274 // Get the Hi+Offset-Lo expression.
1275 const MCExpr *Diff =
1276 MCBinaryExpr::CreateSub(Plus,
1277 MCSymbolRefExpr::Create(Lo, OutContext),
1280 if (!MAI->hasSetDirective())
1281 OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1283 // Otherwise, emit with .set (aka assignment).
1284 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1285 OutStreamer.EmitAssignment(SetLabel, Diff);
1286 OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1290 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1291 /// where the size in bytes of the directive is specified by Size and Label
1292 /// specifies the label. This implicitly uses .set if it is available.
1293 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1297 // Emit Label+Offset
1298 const MCExpr *Plus =
1299 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Label, OutContext),
1300 MCConstantExpr::Create(Offset, OutContext),
1303 OutStreamer.EmitValue(Plus, 4, 0/*AddrSpace*/);
1307 //===----------------------------------------------------------------------===//
1309 // EmitAlignment - Emit an alignment directive to the specified power of
1310 // two boundary. For example, if you pass in 3 here, you will get an 8
1311 // byte alignment. If a global value is specified, and if that global has
1312 // an explicit alignment requested, it will override the alignment request
1313 // if required for correctness.
1315 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1316 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
1318 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1320 if (getCurrentSection()->getKind().isText())
1321 OutStreamer.EmitCodeAlignment(1 << NumBits);
1323 OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1326 //===----------------------------------------------------------------------===//
1327 // Constant emission.
1328 //===----------------------------------------------------------------------===//
1330 /// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1332 static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1333 MCContext &Ctx = AP.OutContext;
1335 if (CV->isNullValue() || isa<UndefValue>(CV))
1336 return MCConstantExpr::Create(0, Ctx);
1338 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1339 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1341 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1342 return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1344 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1345 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1347 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1349 llvm_unreachable("Unknown constant value to lower!");
1350 return MCConstantExpr::Create(0, Ctx);
1353 switch (CE->getOpcode()) {
1355 // If the code isn't optimized, there may be outstanding folding
1356 // opportunities. Attempt to fold the expression using TargetData as a
1357 // last resort before giving up.
1359 ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1361 return LowerConstant(C, AP);
1363 // Otherwise report the problem to the user.
1366 raw_string_ostream OS(S);
1367 OS << "Unsupported expression in static initializer: ";
1368 WriteAsOperand(OS, CE, /*PrintType=*/false,
1369 !AP.MF ? 0 : AP.MF->getFunction()->getParent());
1370 report_fatal_error(OS.str());
1372 return MCConstantExpr::Create(0, Ctx);
1373 case Instruction::GetElementPtr: {
1374 const TargetData &TD = *AP.TM.getTargetData();
1375 // Generate a symbolic expression for the byte address
1376 const Constant *PtrVal = CE->getOperand(0);
1377 SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1378 int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1381 const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1385 // Truncate/sext the offset to the pointer size.
1386 if (TD.getPointerSizeInBits() != 64) {
1387 int SExtAmount = 64-TD.getPointerSizeInBits();
1388 Offset = (Offset << SExtAmount) >> SExtAmount;
1391 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1395 case Instruction::Trunc:
1396 // We emit the value and depend on the assembler to truncate the generated
1397 // expression properly. This is important for differences between
1398 // blockaddress labels. Since the two labels are in the same function, it
1399 // is reasonable to treat their delta as a 32-bit value.
1401 case Instruction::BitCast:
1402 return LowerConstant(CE->getOperand(0), AP);
1404 case Instruction::IntToPtr: {
1405 const TargetData &TD = *AP.TM.getTargetData();
1406 // Handle casts to pointers by changing them into casts to the appropriate
1407 // integer type. This promotes constant folding and simplifies this code.
1408 Constant *Op = CE->getOperand(0);
1409 Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1411 return LowerConstant(Op, AP);
1414 case Instruction::PtrToInt: {
1415 const TargetData &TD = *AP.TM.getTargetData();
1416 // Support only foldable casts to/from pointers that can be eliminated by
1417 // changing the pointer to the appropriately sized integer type.
1418 Constant *Op = CE->getOperand(0);
1419 const Type *Ty = CE->getType();
1421 const MCExpr *OpExpr = LowerConstant(Op, AP);
1423 // We can emit the pointer value into this slot if the slot is an
1424 // integer slot equal to the size of the pointer.
1425 if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1428 // Otherwise the pointer is smaller than the resultant integer, mask off
1429 // the high bits so we are sure to get a proper truncation if the input is
1431 unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1432 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1433 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1436 // The MC library also has a right-shift operator, but it isn't consistently
1437 // signed or unsigned between different targets.
1438 case Instruction::Add:
1439 case Instruction::Sub:
1440 case Instruction::Mul:
1441 case Instruction::SDiv:
1442 case Instruction::SRem:
1443 case Instruction::Shl:
1444 case Instruction::And:
1445 case Instruction::Or:
1446 case Instruction::Xor: {
1447 const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1448 const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1449 switch (CE->getOpcode()) {
1450 default: llvm_unreachable("Unknown binary operator constant cast expr");
1451 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1452 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1453 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1454 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1455 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1456 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1457 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1458 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1459 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1465 static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1468 static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1470 if (AddrSpace != 0 || !CA->isString()) {
1471 // Not a string. Print the values in successive locations
1472 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1473 EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1477 // Otherwise, it can be emitted as .ascii.
1478 SmallVector<char, 128> TmpVec;
1479 TmpVec.reserve(CA->getNumOperands());
1480 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1481 TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1483 AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1486 static void EmitGlobalConstantVector(const ConstantVector *CV,
1487 unsigned AddrSpace, AsmPrinter &AP) {
1488 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1489 EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1492 static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1493 unsigned AddrSpace, AsmPrinter &AP) {
1494 // Print the fields in successive locations. Pad to align if needed!
1495 const TargetData *TD = AP.TM.getTargetData();
1496 unsigned Size = TD->getTypeAllocSize(CS->getType());
1497 const StructLayout *Layout = TD->getStructLayout(CS->getType());
1498 uint64_t SizeSoFar = 0;
1499 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1500 const Constant *Field = CS->getOperand(i);
1502 // Check if padding is needed and insert one or more 0s.
1503 uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1504 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1505 - Layout->getElementOffset(i)) - FieldSize;
1506 SizeSoFar += FieldSize + PadSize;
1508 // Now print the actual field value.
1509 EmitGlobalConstantImpl(Field, AddrSpace, AP);
1511 // Insert padding - this may include padding to increase the size of the
1512 // current field up to the ABI size (if the struct is not packed) as well
1513 // as padding to ensure that the next field starts at the right offset.
1514 AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1516 assert(SizeSoFar == Layout->getSizeInBytes() &&
1517 "Layout of constant struct may be incorrect!");
1520 static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1522 // FP Constants are printed as integer constants to avoid losing
1524 if (CFP->getType()->isDoubleTy()) {
1525 if (AP.isVerbose()) {
1526 double Val = CFP->getValueAPF().convertToDouble();
1527 AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1530 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1531 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1535 if (CFP->getType()->isFloatTy()) {
1536 if (AP.isVerbose()) {
1537 float Val = CFP->getValueAPF().convertToFloat();
1538 AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1540 uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1541 AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1545 if (CFP->getType()->isX86_FP80Ty()) {
1546 // all long double variants are printed as hex
1547 // API needed to prevent premature destruction
1548 APInt API = CFP->getValueAPF().bitcastToAPInt();
1549 const uint64_t *p = API.getRawData();
1550 if (AP.isVerbose()) {
1551 // Convert to double so we can print the approximate val as a comment.
1552 APFloat DoubleVal = CFP->getValueAPF();
1554 DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1556 AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1557 << DoubleVal.convertToDouble() << '\n';
1560 if (AP.TM.getTargetData()->isBigEndian()) {
1561 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1562 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1564 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1565 AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1568 // Emit the tail padding for the long double.
1569 const TargetData &TD = *AP.TM.getTargetData();
1570 AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1571 TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1575 assert(CFP->getType()->isPPC_FP128Ty() &&
1576 "Floating point constant type not handled");
1577 // All long double variants are printed as hex
1578 // API needed to prevent premature destruction.
1579 APInt API = CFP->getValueAPF().bitcastToAPInt();
1580 const uint64_t *p = API.getRawData();
1581 if (AP.TM.getTargetData()->isBigEndian()) {
1582 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1583 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1585 AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1586 AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1590 static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1591 unsigned AddrSpace, AsmPrinter &AP) {
1592 const TargetData *TD = AP.TM.getTargetData();
1593 unsigned BitWidth = CI->getBitWidth();
1594 assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1596 // We don't expect assemblers to support integer data directives
1597 // for more than 64 bits, so we emit the data in at most 64-bit
1598 // quantities at a time.
1599 const uint64_t *RawData = CI->getValue().getRawData();
1600 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1601 uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1602 AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1606 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1608 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1609 uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1610 return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1613 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1614 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1621 AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1622 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1625 EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1630 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1631 return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1633 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1634 return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1636 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1637 return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1639 if (isa<ConstantPointerNull>(CV)) {
1640 unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1641 AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1645 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1646 return EmitGlobalConstantVector(V, AddrSpace, AP);
1648 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
1649 // thread the streamer with EmitValue.
1650 AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1651 AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1655 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1656 void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1657 uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1659 EmitGlobalConstantImpl(CV, AddrSpace, *this);
1660 else if (MAI->hasSubsectionsViaSymbols()) {
1661 // If the global has zero size, emit a single byte so that two labels don't
1662 // look like they are at the same location.
1663 OutStreamer.EmitIntValue(0, 1, AddrSpace);
1667 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1668 // Target doesn't support this yet!
1669 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1672 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1674 OS << '+' << Offset;
1675 else if (Offset < 0)
1679 //===----------------------------------------------------------------------===//
1680 // Symbol Lowering Routines.
1681 //===----------------------------------------------------------------------===//
1683 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1684 /// temporary label with the specified stem and unique ID.
1685 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1686 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1690 /// GetTempSymbol - Return an assembler temporary label with the specified
1692 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1693 return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1698 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1699 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1702 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1703 return MMI->getAddrLabelSymbol(BB);
1706 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
1707 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1708 return OutContext.GetOrCreateSymbol
1709 (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1710 + "_" + Twine(CPID));
1713 /// GetJTISymbol - Return the symbol for the specified jump table entry.
1714 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1715 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1718 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
1719 /// FIXME: privatize to AsmPrinter.
1720 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1721 return OutContext.GetOrCreateSymbol
1722 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1723 Twine(UID) + "_set_" + Twine(MBBID));
1726 /// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1727 /// global value name as its base, with the specified suffix, and where the
1728 /// symbol is forced to have private linkage if ForcePrivate is true.
1729 MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1731 bool ForcePrivate) const {
1732 SmallString<60> NameStr;
1733 Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1734 NameStr.append(Suffix.begin(), Suffix.end());
1735 return OutContext.GetOrCreateSymbol(NameStr.str());
1738 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1740 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1741 SmallString<60> NameStr;
1742 Mang->getNameWithPrefix(NameStr, Sym);
1743 return OutContext.GetOrCreateSymbol(NameStr.str());
1748 /// PrintParentLoopComment - Print comments about parent loops of this one.
1749 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1750 unsigned FunctionNumber) {
1751 if (Loop == 0) return;
1752 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1753 OS.indent(Loop->getLoopDepth()*2)
1754 << "Parent Loop BB" << FunctionNumber << "_"
1755 << Loop->getHeader()->getNumber()
1756 << " Depth=" << Loop->getLoopDepth() << '\n';
1760 /// PrintChildLoopComment - Print comments about child loops within
1761 /// the loop for this basic block, with nesting.
1762 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1763 unsigned FunctionNumber) {
1764 // Add child loop information
1765 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1766 OS.indent((*CL)->getLoopDepth()*2)
1767 << "Child Loop BB" << FunctionNumber << "_"
1768 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1770 PrintChildLoopComment(OS, *CL, FunctionNumber);
1774 /// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1775 static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1776 const MachineLoopInfo *LI,
1777 const AsmPrinter &AP) {
1778 // Add loop depth information
1779 const MachineLoop *Loop = LI->getLoopFor(&MBB);
1780 if (Loop == 0) return;
1782 MachineBasicBlock *Header = Loop->getHeader();
1783 assert(Header && "No header for loop");
1785 // If this block is not a loop header, just print out what is the loop header
1787 if (Header != &MBB) {
1788 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
1789 Twine(AP.getFunctionNumber())+"_" +
1790 Twine(Loop->getHeader()->getNumber())+
1791 " Depth="+Twine(Loop->getLoopDepth()));
1795 // Otherwise, it is a loop header. Print out information about child and
1797 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1799 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1802 OS.indent(Loop->getLoopDepth()*2-2);
1807 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1809 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1813 /// EmitBasicBlockStart - This method prints the label for the specified
1814 /// MachineBasicBlock, an alignment (if present) and a comment describing
1815 /// it if appropriate.
1816 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1817 // Emit an alignment directive for this block, if needed.
1818 if (unsigned Align = MBB->getAlignment())
1819 EmitAlignment(Log2_32(Align));
1821 // If the block has its address taken, emit any labels that were used to
1822 // reference the block. It is possible that there is more than one label
1823 // here, because multiple LLVM BB's may have been RAUW'd to this block after
1824 // the references were generated.
1825 if (MBB->hasAddressTaken()) {
1826 const BasicBlock *BB = MBB->getBasicBlock();
1828 OutStreamer.AddComment("Block address taken");
1830 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1832 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1833 OutStreamer.EmitLabel(Syms[i]);
1836 // Print the main label for the block.
1837 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1838 if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1839 if (const BasicBlock *BB = MBB->getBasicBlock())
1841 OutStreamer.AddComment("%" + BB->getName());
1843 EmitBasicBlockLoopComments(*MBB, LI, *this);
1845 // NOTE: Want this comment at start of line, don't emit with AddComment.
1846 OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1847 Twine(MBB->getNumber()) + ":");
1851 if (const BasicBlock *BB = MBB->getBasicBlock())
1853 OutStreamer.AddComment("%" + BB->getName());
1854 EmitBasicBlockLoopComments(*MBB, LI, *this);
1857 OutStreamer.EmitLabel(MBB->getSymbol());
1861 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
1862 bool IsDefinition) const {
1863 MCSymbolAttr Attr = MCSA_Invalid;
1865 switch (Visibility) {
1867 case GlobalValue::HiddenVisibility:
1869 Attr = MAI->getHiddenVisibilityAttr();
1871 Attr = MAI->getHiddenDeclarationVisibilityAttr();
1873 case GlobalValue::ProtectedVisibility:
1874 Attr = MAI->getProtectedVisibilityAttr();
1878 if (Attr != MCSA_Invalid)
1879 OutStreamer.EmitSymbolAttribute(Sym, Attr);
1882 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
1883 /// exactly one predecessor and the control transfer mechanism between
1884 /// the predecessor and this block is a fall-through.
1886 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1887 // If this is a landing pad, it isn't a fall through. If it has no preds,
1888 // then nothing falls through to it.
1889 if (MBB->isLandingPad() || MBB->pred_empty())
1892 // If there isn't exactly one predecessor, it can't be a fall through.
1893 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1895 if (PI2 != MBB->pred_end())
1898 // The predecessor has to be immediately before this block.
1899 const MachineBasicBlock *Pred = *PI;
1901 if (!Pred->isLayoutSuccessor(MBB))
1904 // If the block is completely empty, then it definitely does fall through.
1908 // Otherwise, check the last instruction.
1909 const MachineInstr &LastInst = Pred->back();
1910 return !LastInst.getDesc().isBarrier();
1915 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1916 if (!S->usesMetadata())
1919 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1920 gcp_map_type::iterator GCPI = GCMap.find(S);
1921 if (GCPI != GCMap.end())
1922 return GCPI->second;
1924 const char *Name = S->getName().c_str();
1926 for (GCMetadataPrinterRegistry::iterator
1927 I = GCMetadataPrinterRegistry::begin(),
1928 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1929 if (strcmp(Name, I->getName()) == 0) {
1930 GCMetadataPrinter *GMP = I->instantiate();
1932 GCMap.insert(std::make_pair(S, GMP));
1936 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));