AsmPrinter.cpp revision a7b611c10d0e5fef5870d854518e639ce3d3c6be
1//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the AsmPrinter class.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "asm-printer"
15#include "llvm/CodeGen/AsmPrinter.h"
16#include "DwarfDebug.h"
17#include "DwarfException.h"
18#include "llvm/Module.h"
19#include "llvm/CodeGen/GCMetadataPrinter.h"
20#include "llvm/CodeGen/MachineConstantPool.h"
21#include "llvm/CodeGen/MachineFrameInfo.h"
22#include "llvm/CodeGen/MachineFunction.h"
23#include "llvm/CodeGen/MachineJumpTableInfo.h"
24#include "llvm/CodeGen/MachineLoopInfo.h"
25#include "llvm/CodeGen/MachineModuleInfo.h"
26#include "llvm/Analysis/ConstantFolding.h"
27#include "llvm/Analysis/DebugInfo.h"
28#include "llvm/MC/MCAsmInfo.h"
29#include "llvm/MC/MCContext.h"
30#include "llvm/MC/MCExpr.h"
31#include "llvm/MC/MCInst.h"
32#include "llvm/MC/MCSection.h"
33#include "llvm/MC/MCStreamer.h"
34#include "llvm/MC/MCSymbol.h"
35#include "llvm/Target/Mangler.h"
36#include "llvm/Target/TargetData.h"
37#include "llvm/Target/TargetInstrInfo.h"
38#include "llvm/Target/TargetLowering.h"
39#include "llvm/Target/TargetLoweringObjectFile.h"
40#include "llvm/Target/TargetRegisterInfo.h"
41#include "llvm/ADT/SmallString.h"
42#include "llvm/ADT/Statistic.h"
43#include "llvm/Support/ErrorHandling.h"
44#include "llvm/Support/Format.h"
45#include "llvm/Support/Timer.h"
46using namespace llvm;
47
48static const char *DWARFGroupName = "DWARF Emission";
49static const char *DbgTimerName = "DWARF Debug Writer";
50static const char *EHTimerName = "DWARF Exception Writer";
51
52STATISTIC(EmittedInsts, "Number of machine instrs printed");
53
54char AsmPrinter::ID = 0;
55
56typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
57static gcp_map_type &getGCMap(void *&P) {
58  if (P == 0)
59    P = new gcp_map_type();
60  return *(gcp_map_type*)P;
61}
62
63
64AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
65  : MachineFunctionPass(&ID),
66    TM(tm), MAI(tm.getMCAsmInfo()),
67    OutContext(Streamer.getContext()),
68    OutStreamer(Streamer),
69    LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
70  DD = 0; DE = 0; MMI = 0; LI = 0;
71  GCMetadataPrinters = 0;
72  VerboseAsm = Streamer.isVerboseAsm();
73}
74
75AsmPrinter::~AsmPrinter() {
76  assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized");
77
78  if (GCMetadataPrinters != 0) {
79    gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
80
81    for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
82      delete I->second;
83    delete &GCMap;
84    GCMetadataPrinters = 0;
85  }
86
87  delete &OutStreamer;
88}
89
90/// getFunctionNumber - Return a unique ID for the current function.
91///
92unsigned AsmPrinter::getFunctionNumber() const {
93  return MF->getFunctionNumber();
94}
95
96const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
97  return TM.getTargetLowering()->getObjFileLowering();
98}
99
100
101/// getTargetData - Return information about data layout.
102const TargetData &AsmPrinter::getTargetData() const {
103  return *TM.getTargetData();
104}
105
106/// getCurrentSection() - Return the current section we are emitting to.
107const MCSection *AsmPrinter::getCurrentSection() const {
108  return OutStreamer.getCurrentSection();
109}
110
111
112
113void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
114  AU.setPreservesAll();
115  MachineFunctionPass::getAnalysisUsage(AU);
116  AU.addRequired<MachineModuleInfo>();
117  AU.addRequired<GCModuleInfo>();
118  if (isVerbose())
119    AU.addRequired<MachineLoopInfo>();
120}
121
122bool AsmPrinter::doInitialization(Module &M) {
123  MMI = getAnalysisIfAvailable<MachineModuleInfo>();
124  MMI->AnalyzeModule(M);
125
126  // Initialize TargetLoweringObjectFile.
127  const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
128    .Initialize(OutContext, TM);
129
130  Mang = new Mangler(OutContext, *TM.getTargetData());
131
132  // Allow the target to emit any magic that it wants at the start of the file.
133  EmitStartOfAsmFile(M);
134
135  // Very minimal debug info. It is ignored if we emit actual debug info. If we
136  // don't, this at least helps the user find where a global came from.
137  if (MAI->hasSingleParameterDotFile()) {
138    // .file "foo.c"
139    OutStreamer.EmitFileDirective(M.getModuleIdentifier());
140  }
141
142  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
143  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
144  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
145    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
146      MP->beginAssembly(*this);
147
148  // Emit module-level inline asm if it exists.
149  if (!M.getModuleInlineAsm().empty()) {
150    OutStreamer.AddComment("Start of file scope inline assembly");
151    OutStreamer.AddBlankLine();
152    EmitInlineAsm(M.getModuleInlineAsm(), 0/*no loc cookie*/);
153    OutStreamer.AddComment("End of file scope inline assembly");
154    OutStreamer.AddBlankLine();
155  }
156
157  if (MAI->doesSupportDebugInformation())
158    DD = new DwarfDebug(this, &M);
159
160  if (MAI->doesSupportExceptionHandling())
161    DE = new DwarfException(this);
162
163  return false;
164}
165
166void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
167  switch ((GlobalValue::LinkageTypes)Linkage) {
168  case GlobalValue::CommonLinkage:
169  case GlobalValue::LinkOnceAnyLinkage:
170  case GlobalValue::LinkOnceODRLinkage:
171  case GlobalValue::WeakAnyLinkage:
172  case GlobalValue::WeakODRLinkage:
173  case GlobalValue::LinkerPrivateLinkage:
174    if (MAI->getWeakDefDirective() != 0) {
175      // .globl _foo
176      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
177      // .weak_definition _foo
178      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
179    } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) {
180      // .globl _foo
181      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
182      // FIXME: linkonce should be a section attribute, handled by COFF Section
183      // assignment.
184      // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce
185      // .linkonce discard
186      // FIXME: It would be nice to use .linkonce samesize for non-common
187      // globals.
188      OutStreamer.EmitRawText(StringRef(LinkOnce));
189    } else {
190      // .weak _foo
191      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
192    }
193    break;
194  case GlobalValue::DLLExportLinkage:
195  case GlobalValue::AppendingLinkage:
196    // FIXME: appending linkage variables should go into a section of
197    // their name or something.  For now, just emit them as external.
198  case GlobalValue::ExternalLinkage:
199    // If external or appending, declare as a global symbol.
200    // .globl _foo
201    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
202    break;
203  case GlobalValue::PrivateLinkage:
204  case GlobalValue::InternalLinkage:
205    break;
206  default:
207    llvm_unreachable("Unknown linkage type!");
208  }
209}
210
211
212/// EmitGlobalVariable - Emit the specified global variable to the .s file.
213void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
214  if (!GV->hasInitializer())   // External globals require no code.
215    return;
216
217  // Check to see if this is a special global used by LLVM, if so, emit it.
218  if (EmitSpecialLLVMGlobal(GV))
219    return;
220
221  MCSymbol *GVSym = Mang->getSymbol(GV);
222  EmitVisibility(GVSym, GV->getVisibility());
223
224  if (MAI->hasDotTypeDotSizeDirective())
225    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
226
227  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
228
229  const TargetData *TD = TM.getTargetData();
230  unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType());
231
232  // If the alignment is specified, we *must* obey it.  Overaligning a global
233  // with a specified alignment is a prompt way to break globals emitted to
234  // sections and expected to be contiguous (e.g. ObjC metadata).
235  unsigned AlignLog;
236  if (unsigned GVAlign = GV->getAlignment())
237    AlignLog = Log2_32(GVAlign);
238  else
239    AlignLog = TD->getPreferredAlignmentLog(GV);
240
241  // Handle common and BSS local symbols (.lcomm).
242  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
243    if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
244
245    if (isVerbose()) {
246      WriteAsOperand(OutStreamer.GetCommentOS(), GV,
247                     /*PrintType=*/false, GV->getParent());
248      OutStreamer.GetCommentOS() << '\n';
249    }
250
251    // Handle common symbols.
252    if (GVKind.isCommon()) {
253      // .comm _foo, 42, 4
254      OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
255      return;
256    }
257
258    // Handle local BSS symbols.
259    if (MAI->hasMachoZeroFillDirective()) {
260      const MCSection *TheSection =
261        getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
262      // .zerofill __DATA, __bss, _foo, 400, 5
263      OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
264      return;
265    }
266
267    if (MAI->hasLCOMMDirective()) {
268      // .lcomm _foo, 42
269      OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
270      return;
271    }
272
273    // .local _foo
274    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
275    // .comm _foo, 42, 4
276    OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
277    return;
278  }
279
280  const MCSection *TheSection =
281    getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
282
283  // Handle the zerofill directive on darwin, which is a special form of BSS
284  // emission.
285  if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
286    if (Size == 0) Size = 1;  // zerofill of 0 bytes is undefined.
287
288    // .globl _foo
289    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
290    // .zerofill __DATA, __common, _foo, 400, 5
291    OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
292    return;
293  }
294
295  OutStreamer.SwitchSection(TheSection);
296
297  EmitLinkage(GV->getLinkage(), GVSym);
298  EmitAlignment(AlignLog, GV);
299
300  if (isVerbose()) {
301    WriteAsOperand(OutStreamer.GetCommentOS(), GV,
302                   /*PrintType=*/false, GV->getParent());
303    OutStreamer.GetCommentOS() << '\n';
304  }
305  OutStreamer.EmitLabel(GVSym);
306
307  EmitGlobalConstant(GV->getInitializer());
308
309  if (MAI->hasDotTypeDotSizeDirective())
310    // .size foo, 42
311    OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
312
313  OutStreamer.AddBlankLine();
314}
315
316/// EmitFunctionHeader - This method emits the header for the current
317/// function.
318void AsmPrinter::EmitFunctionHeader() {
319  // Print out constants referenced by the function
320  EmitConstantPool();
321
322  // Print the 'header' of function.
323  const Function *F = MF->getFunction();
324
325  OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
326  EmitVisibility(CurrentFnSym, F->getVisibility());
327
328  EmitLinkage(F->getLinkage(), CurrentFnSym);
329  EmitAlignment(MF->getAlignment(), F);
330
331  if (MAI->hasDotTypeDotSizeDirective())
332    OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
333
334  if (isVerbose()) {
335    WriteAsOperand(OutStreamer.GetCommentOS(), F,
336                   /*PrintType=*/false, F->getParent());
337    OutStreamer.GetCommentOS() << '\n';
338  }
339
340  // Emit the CurrentFnSym.  This is a virtual function to allow targets to
341  // do their wild and crazy things as required.
342  EmitFunctionEntryLabel();
343
344  // If the function had address-taken blocks that got deleted, then we have
345  // references to the dangling symbols.  Emit them at the start of the function
346  // so that we don't get references to undefined symbols.
347  std::vector<MCSymbol*> DeadBlockSyms;
348  MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
349  for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
350    OutStreamer.AddComment("Address taken block that was later removed");
351    OutStreamer.EmitLabel(DeadBlockSyms[i]);
352  }
353
354  // Add some workaround for linkonce linkage on Cygwin\MinGW.
355  if (MAI->getLinkOnceDirective() != 0 &&
356      (F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
357    // FIXME: What is this?
358    MCSymbol *FakeStub =
359      OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
360                                   CurrentFnSym->getName());
361    OutStreamer.EmitLabel(FakeStub);
362  }
363
364  // Emit pre-function debug and/or EH information.
365  if (DE) {
366    if (TimePassesIsEnabled) {
367      NamedRegionTimer T(EHTimerName, DWARFGroupName);
368      DE->BeginFunction(MF);
369    } else {
370      DE->BeginFunction(MF);
371    }
372  }
373  if (DD) {
374    if (TimePassesIsEnabled) {
375      NamedRegionTimer T(DbgTimerName, DWARFGroupName);
376      DD->beginFunction(MF);
377    } else {
378      DD->beginFunction(MF);
379    }
380  }
381}
382
383/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
384/// function.  This can be overridden by targets as required to do custom stuff.
385void AsmPrinter::EmitFunctionEntryLabel() {
386  OutStreamer.EmitLabel(CurrentFnSym);
387}
388
389
390/// EmitComments - Pretty-print comments for instructions.
391static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
392  const MachineFunction *MF = MI.getParent()->getParent();
393  const TargetMachine &TM = MF->getTarget();
394
395  DebugLoc DL = MI.getDebugLoc();
396  if (!DL.isUnknown()) {          // Print source line info.
397    DIScope Scope(DL.getScope(MF->getFunction()->getContext()));
398    // Omit the directory, because it's likely to be long and uninteresting.
399    if (Scope.Verify())
400      CommentOS << Scope.getFilename();
401    else
402      CommentOS << "<unknown>";
403    CommentOS << ':' << DL.getLine();
404    if (DL.getCol() != 0)
405      CommentOS << ':' << DL.getCol();
406    CommentOS << '\n';
407  }
408
409  // Check for spills and reloads
410  int FI;
411
412  const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
413
414  // We assume a single instruction only has a spill or reload, not
415  // both.
416  const MachineMemOperand *MMO;
417  if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
418    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
419      MMO = *MI.memoperands_begin();
420      CommentOS << MMO->getSize() << "-byte Reload\n";
421    }
422  } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
423    if (FrameInfo->isSpillSlotObjectIndex(FI))
424      CommentOS << MMO->getSize() << "-byte Folded Reload\n";
425  } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
426    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
427      MMO = *MI.memoperands_begin();
428      CommentOS << MMO->getSize() << "-byte Spill\n";
429    }
430  } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
431    if (FrameInfo->isSpillSlotObjectIndex(FI))
432      CommentOS << MMO->getSize() << "-byte Folded Spill\n";
433  }
434
435  // Check for spill-induced copies
436  unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
437  if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
438                                     SrcSubIdx, DstSubIdx)) {
439    if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
440      CommentOS << " Reload Reuse\n";
441  }
442}
443
444/// EmitImplicitDef - This method emits the specified machine instruction
445/// that is an implicit def.
446static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
447  unsigned RegNo = MI->getOperand(0).getReg();
448  AP.OutStreamer.AddComment(Twine("implicit-def: ") +
449                            AP.TM.getRegisterInfo()->getName(RegNo));
450  AP.OutStreamer.AddBlankLine();
451}
452
453static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
454  std::string Str = "kill:";
455  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
456    const MachineOperand &Op = MI->getOperand(i);
457    assert(Op.isReg() && "KILL instruction must have only register operands");
458    Str += ' ';
459    Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
460    Str += (Op.isDef() ? "<def>" : "<kill>");
461  }
462  AP.OutStreamer.AddComment(Str);
463  AP.OutStreamer.AddBlankLine();
464}
465
466/// EmitDebugValueComment - This method handles the target-independent form
467/// of DBG_VALUE, returning true if it was able to do so.  A false return
468/// means the target will need to handle MI in EmitInstruction.
469static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
470  // This code handles only the 3-operand target-independent form.
471  if (MI->getNumOperands() != 3)
472    return false;
473
474  SmallString<128> Str;
475  raw_svector_ostream OS(Str);
476  OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
477
478  // cast away const; DIetc do not take const operands for some reason.
479  DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
480  OS << V.getName() << " <- ";
481
482  // Register or immediate value. Register 0 means undef.
483  if (MI->getOperand(0).isFPImm()) {
484    APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
485    if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
486      OS << (double)APF.convertToFloat();
487    } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
488      OS << APF.convertToDouble();
489    } else {
490      // There is no good way to print long double.  Convert a copy to
491      // double.  Ah well, it's only a comment.
492      bool ignored;
493      APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
494                  &ignored);
495      OS << "(long double) " << APF.convertToDouble();
496    }
497  } else if (MI->getOperand(0).isImm()) {
498    OS << MI->getOperand(0).getImm();
499  } else {
500    assert(MI->getOperand(0).isReg() && "Unknown operand type");
501    if (MI->getOperand(0).getReg() == 0) {
502      // Suppress offset, it is not meaningful here.
503      OS << "undef";
504      // NOTE: Want this comment at start of line, don't emit with AddComment.
505      AP.OutStreamer.EmitRawText(OS.str());
506      return true;
507    }
508    OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
509  }
510
511  OS << '+' << MI->getOperand(1).getImm();
512  // NOTE: Want this comment at start of line, don't emit with AddComment.
513  AP.OutStreamer.EmitRawText(OS.str());
514  return true;
515}
516
517/// EmitFunctionBody - This method emits the body and trailer for a
518/// function.
519void AsmPrinter::EmitFunctionBody() {
520  // Emit target-specific gunk before the function body.
521  EmitFunctionBodyStart();
522
523  bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
524
525  // Print out code for the function.
526  bool HasAnyRealCode = false;
527  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
528       I != E; ++I) {
529    // Print a label for the basic block.
530    EmitBasicBlockStart(I);
531    for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
532         II != IE; ++II) {
533      // Print the assembly for the instruction.
534      if (!II->isLabel() && !II->isImplicitDef() && !II->isKill()) {
535        HasAnyRealCode = true;
536        ++EmittedInsts;
537      }
538
539      if (ShouldPrintDebugScopes) {
540	if (TimePassesIsEnabled) {
541	  NamedRegionTimer T(DbgTimerName, DWARFGroupName);
542	  DD->beginScope(II);
543	} else {
544	  DD->beginScope(II);
545	}
546      }
547
548      if (isVerbose())
549        EmitComments(*II, OutStreamer.GetCommentOS());
550
551      switch (II->getOpcode()) {
552      case TargetOpcode::DBG_LABEL:
553      case TargetOpcode::EH_LABEL:
554      case TargetOpcode::GC_LABEL:
555        OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
556        break;
557      case TargetOpcode::INLINEASM:
558        EmitInlineAsm(II);
559        break;
560      case TargetOpcode::DBG_VALUE:
561        if (isVerbose()) {
562          if (!EmitDebugValueComment(II, *this))
563            EmitInstruction(II);
564        }
565        break;
566      case TargetOpcode::IMPLICIT_DEF:
567        if (isVerbose()) EmitImplicitDef(II, *this);
568        break;
569      case TargetOpcode::KILL:
570        if (isVerbose()) EmitKill(II, *this);
571        break;
572      default:
573        EmitInstruction(II);
574        break;
575      }
576
577      if (ShouldPrintDebugScopes) {
578	if (TimePassesIsEnabled) {
579	  NamedRegionTimer T(DbgTimerName, DWARFGroupName);
580	  DD->endScope(II);
581	} else {
582	  DD->endScope(II);
583	}
584      }
585    }
586  }
587
588  // If the function is empty and the object file uses .subsections_via_symbols,
589  // then we need to emit *something* to the function body to prevent the
590  // labels from collapsing together.  Just emit a noop.
591  if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) {
592    MCInst Noop;
593    TM.getInstrInfo()->getNoopForMachoTarget(Noop);
594    if (Noop.getOpcode()) {
595      OutStreamer.AddComment("avoids zero-length function");
596      OutStreamer.EmitInstruction(Noop);
597    } else  // Target not mc-ized yet.
598      OutStreamer.EmitRawText(StringRef("\tnop\n"));
599  }
600
601  // Emit target-specific gunk after the function body.
602  EmitFunctionBodyEnd();
603
604  // If the target wants a .size directive for the size of the function, emit
605  // it.
606  if (MAI->hasDotTypeDotSizeDirective()) {
607    // Create a symbol for the end of function, so we can get the size as
608    // difference between the function label and the temp label.
609    MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
610    OutStreamer.EmitLabel(FnEndLabel);
611
612    const MCExpr *SizeExp =
613      MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
614                              MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
615                              OutContext);
616    OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
617  }
618
619  // Emit post-function debug information.
620  if (DD) {
621    if (TimePassesIsEnabled) {
622      NamedRegionTimer T(DbgTimerName, DWARFGroupName);
623      DD->endFunction(MF);
624    } else {
625      DD->endFunction(MF);
626    }
627  }
628  if (DE) {
629    if (TimePassesIsEnabled) {
630      NamedRegionTimer T(EHTimerName, DWARFGroupName);
631      DE->EndFunction();
632    } else {
633      DE->EndFunction();
634    }
635  }
636  MMI->EndFunction();
637
638  // Print out jump tables referenced by the function.
639  EmitJumpTableInfo();
640
641  OutStreamer.AddBlankLine();
642}
643
644
645bool AsmPrinter::doFinalization(Module &M) {
646  // Emit global variables.
647  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
648       I != E; ++I)
649    EmitGlobalVariable(I);
650
651  // Finalize debug and EH information.
652  if (DE) {
653    if (TimePassesIsEnabled) {
654      NamedRegionTimer T(EHTimerName, DWARFGroupName);
655      DE->EndModule();
656    } else {
657      DE->EndModule();
658    }
659    delete DE; DE = 0;
660  }
661  if (DD) {
662    if (TimePassesIsEnabled) {
663      NamedRegionTimer T(DbgTimerName, DWARFGroupName);
664      DD->endModule();
665    } else {
666      DD->endModule();
667    }
668    delete DD; DD = 0;
669  }
670
671  // If the target wants to know about weak references, print them all.
672  if (MAI->getWeakRefDirective()) {
673    // FIXME: This is not lazy, it would be nice to only print weak references
674    // to stuff that is actually used.  Note that doing so would require targets
675    // to notice uses in operands (due to constant exprs etc).  This should
676    // happen with the MC stuff eventually.
677
678    // Print out module-level global variables here.
679    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
680         I != E; ++I) {
681      if (!I->hasExternalWeakLinkage()) continue;
682      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
683    }
684
685    for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
686      if (!I->hasExternalWeakLinkage()) continue;
687      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
688    }
689  }
690
691  if (MAI->hasSetDirective()) {
692    OutStreamer.AddBlankLine();
693    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
694         I != E; ++I) {
695      MCSymbol *Name = Mang->getSymbol(I);
696
697      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
698      MCSymbol *Target = Mang->getSymbol(GV);
699
700      if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
701        OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
702      else if (I->hasWeakLinkage())
703        OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
704      else
705        assert(I->hasLocalLinkage() && "Invalid alias linkage");
706
707      EmitVisibility(Name, I->getVisibility());
708
709      // Emit the directives as assignments aka .set:
710      OutStreamer.EmitAssignment(Name,
711                                 MCSymbolRefExpr::Create(Target, OutContext));
712    }
713  }
714
715  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
716  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
717  for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
718    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
719      MP->finishAssembly(*this);
720
721  // If we don't have any trampolines, then we don't require stack memory
722  // to be executable. Some targets have a directive to declare this.
723  Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
724  if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
725    if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
726      OutStreamer.SwitchSection(S);
727
728  // Allow the target to emit any magic that it wants at the end of the file,
729  // after everything else has gone out.
730  EmitEndOfAsmFile(M);
731
732  delete Mang; Mang = 0;
733  MMI = 0;
734
735  OutStreamer.Finish();
736  return false;
737}
738
739void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
740  this->MF = &MF;
741  // Get the function symbol.
742  CurrentFnSym = Mang->getSymbol(MF.getFunction());
743
744  if (isVerbose())
745    LI = &getAnalysis<MachineLoopInfo>();
746}
747
748namespace {
749  // SectionCPs - Keep track the alignment, constpool entries per Section.
750  struct SectionCPs {
751    const MCSection *S;
752    unsigned Alignment;
753    SmallVector<unsigned, 4> CPEs;
754    SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
755  };
756}
757
758/// EmitConstantPool - Print to the current output stream assembly
759/// representations of the constants in the constant pool MCP. This is
760/// used to print out constants which have been "spilled to memory" by
761/// the code generator.
762///
763void AsmPrinter::EmitConstantPool() {
764  const MachineConstantPool *MCP = MF->getConstantPool();
765  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
766  if (CP.empty()) return;
767
768  // Calculate sections for constant pool entries. We collect entries to go into
769  // the same section together to reduce amount of section switch statements.
770  SmallVector<SectionCPs, 4> CPSections;
771  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
772    const MachineConstantPoolEntry &CPE = CP[i];
773    unsigned Align = CPE.getAlignment();
774
775    SectionKind Kind;
776    switch (CPE.getRelocationInfo()) {
777    default: llvm_unreachable("Unknown section kind");
778    case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
779    case 1:
780      Kind = SectionKind::getReadOnlyWithRelLocal();
781      break;
782    case 0:
783    switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
784    case 4:  Kind = SectionKind::getMergeableConst4(); break;
785    case 8:  Kind = SectionKind::getMergeableConst8(); break;
786    case 16: Kind = SectionKind::getMergeableConst16();break;
787    default: Kind = SectionKind::getMergeableConst(); break;
788    }
789    }
790
791    const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
792
793    // The number of sections are small, just do a linear search from the
794    // last section to the first.
795    bool Found = false;
796    unsigned SecIdx = CPSections.size();
797    while (SecIdx != 0) {
798      if (CPSections[--SecIdx].S == S) {
799        Found = true;
800        break;
801      }
802    }
803    if (!Found) {
804      SecIdx = CPSections.size();
805      CPSections.push_back(SectionCPs(S, Align));
806    }
807
808    if (Align > CPSections[SecIdx].Alignment)
809      CPSections[SecIdx].Alignment = Align;
810    CPSections[SecIdx].CPEs.push_back(i);
811  }
812
813  // Now print stuff into the calculated sections.
814  for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
815    OutStreamer.SwitchSection(CPSections[i].S);
816    EmitAlignment(Log2_32(CPSections[i].Alignment));
817
818    unsigned Offset = 0;
819    for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
820      unsigned CPI = CPSections[i].CPEs[j];
821      MachineConstantPoolEntry CPE = CP[CPI];
822
823      // Emit inter-object padding for alignment.
824      unsigned AlignMask = CPE.getAlignment() - 1;
825      unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
826      OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
827
828      const Type *Ty = CPE.getType();
829      Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
830
831      // Emit the label with a comment on it.
832      if (isVerbose()) {
833        OutStreamer.GetCommentOS() << "constant pool ";
834        WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
835                          MF->getFunction()->getParent());
836        OutStreamer.GetCommentOS() << '\n';
837      }
838      OutStreamer.EmitLabel(GetCPISymbol(CPI));
839
840      if (CPE.isMachineConstantPoolEntry())
841        EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
842      else
843        EmitGlobalConstant(CPE.Val.ConstVal);
844    }
845  }
846}
847
848/// EmitJumpTableInfo - Print assembly representations of the jump tables used
849/// by the current function to the current output stream.
850///
851void AsmPrinter::EmitJumpTableInfo() {
852  const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
853  if (MJTI == 0) return;
854  if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
855  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
856  if (JT.empty()) return;
857
858  // Pick the directive to use to print the jump table entries, and switch to
859  // the appropriate section.
860  const Function *F = MF->getFunction();
861  bool JTInDiffSection = false;
862  if (// In PIC mode, we need to emit the jump table to the same section as the
863      // function body itself, otherwise the label differences won't make sense.
864      // FIXME: Need a better predicate for this: what about custom entries?
865      MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
866      // We should also do if the section name is NULL or function is declared
867      // in discardable section
868      // FIXME: this isn't the right predicate, should be based on the MCSection
869      // for the function.
870      F->isWeakForLinker()) {
871    OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
872  } else {
873    // Otherwise, drop it in the readonly section.
874    const MCSection *ReadOnlySection =
875      getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
876    OutStreamer.SwitchSection(ReadOnlySection);
877    JTInDiffSection = true;
878  }
879
880  EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
881
882  for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
883    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
884
885    // If this jump table was deleted, ignore it.
886    if (JTBBs.empty()) continue;
887
888    // For the EK_LabelDifference32 entry, if the target supports .set, emit a
889    // .set directive for each unique entry.  This reduces the number of
890    // relocations the assembler will generate for the jump table.
891    if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
892        MAI->hasSetDirective()) {
893      SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
894      const TargetLowering *TLI = TM.getTargetLowering();
895      const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
896      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
897        const MachineBasicBlock *MBB = JTBBs[ii];
898        if (!EmittedSets.insert(MBB)) continue;
899
900        // .set LJTSet, LBB32-base
901        const MCExpr *LHS =
902          MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
903        OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
904                                MCBinaryExpr::CreateSub(LHS, Base, OutContext));
905      }
906    }
907
908    // On some targets (e.g. Darwin) we want to emit two consequtive labels
909    // before each jump table.  The first label is never referenced, but tells
910    // the assembler and linker the extents of the jump table object.  The
911    // second label is actually referenced by the code.
912    if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
913      // FIXME: This doesn't have to have any specific name, just any randomly
914      // named and numbered 'l' label would work.  Simplify GetJTISymbol.
915      OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
916
917    OutStreamer.EmitLabel(GetJTISymbol(JTI));
918
919    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
920      EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
921  }
922}
923
924/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
925/// current stream.
926void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
927                                    const MachineBasicBlock *MBB,
928                                    unsigned UID) const {
929  const MCExpr *Value = 0;
930  switch (MJTI->getEntryKind()) {
931  case MachineJumpTableInfo::EK_Inline:
932    llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
933  case MachineJumpTableInfo::EK_Custom32:
934    Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
935                                                              OutContext);
936    break;
937  case MachineJumpTableInfo::EK_BlockAddress:
938    // EK_BlockAddress - Each entry is a plain address of block, e.g.:
939    //     .word LBB123
940    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
941    break;
942  case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
943    // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
944    // with a relocation as gp-relative, e.g.:
945    //     .gprel32 LBB123
946    MCSymbol *MBBSym = MBB->getSymbol();
947    OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
948    return;
949  }
950
951  case MachineJumpTableInfo::EK_LabelDifference32: {
952    // EK_LabelDifference32 - Each entry is the address of the block minus
953    // the address of the jump table.  This is used for PIC jump tables where
954    // gprel32 is not supported.  e.g.:
955    //      .word LBB123 - LJTI1_2
956    // If the .set directive is supported, this is emitted as:
957    //      .set L4_5_set_123, LBB123 - LJTI1_2
958    //      .word L4_5_set_123
959
960    // If we have emitted set directives for the jump table entries, print
961    // them rather than the entries themselves.  If we're emitting PIC, then
962    // emit the table entries as differences between two text section labels.
963    if (MAI->hasSetDirective()) {
964      // If we used .set, reference the .set's symbol.
965      Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
966                                      OutContext);
967      break;
968    }
969    // Otherwise, use the difference as the jump table entry.
970    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
971    const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
972    Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
973    break;
974  }
975  }
976
977  assert(Value && "Unknown entry kind!");
978
979  unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
980  OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
981}
982
983
984/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
985/// special global used by LLVM.  If so, emit it and return true, otherwise
986/// do nothing and return false.
987bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
988  if (GV->getName() == "llvm.used") {
989    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
990      EmitLLVMUsedList(GV->getInitializer());
991    return true;
992  }
993
994  // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
995  if (GV->getSection() == "llvm.metadata" ||
996      GV->hasAvailableExternallyLinkage())
997    return true;
998
999  if (!GV->hasAppendingLinkage()) return false;
1000
1001  assert(GV->hasInitializer() && "Not a special LLVM global!");
1002
1003  const TargetData *TD = TM.getTargetData();
1004  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
1005  if (GV->getName() == "llvm.global_ctors") {
1006    OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
1007    EmitAlignment(Align, 0);
1008    EmitXXStructorList(GV->getInitializer());
1009
1010    if (TM.getRelocationModel() == Reloc::Static &&
1011        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1012      StringRef Sym(".constructors_used");
1013      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1014                                      MCSA_Reference);
1015    }
1016    return true;
1017  }
1018
1019  if (GV->getName() == "llvm.global_dtors") {
1020    OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
1021    EmitAlignment(Align, 0);
1022    EmitXXStructorList(GV->getInitializer());
1023
1024    if (TM.getRelocationModel() == Reloc::Static &&
1025        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1026      StringRef Sym(".destructors_used");
1027      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1028                                      MCSA_Reference);
1029    }
1030    return true;
1031  }
1032
1033  return false;
1034}
1035
1036/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1037/// global in the specified llvm.used list for which emitUsedDirectiveFor
1038/// is true, as being used with this directive.
1039void AsmPrinter::EmitLLVMUsedList(Constant *List) {
1040  // Should be an array of 'i8*'.
1041  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1042  if (InitList == 0) return;
1043
1044  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1045    const GlobalValue *GV =
1046      dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1047    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
1048      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
1049  }
1050}
1051
1052/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the
1053/// function pointers, ignoring the init priority.
1054void AsmPrinter::EmitXXStructorList(Constant *List) {
1055  // Should be an array of '{ int, void ()* }' structs.  The first value is the
1056  // init priority, which we ignore.
1057  if (!isa<ConstantArray>(List)) return;
1058  ConstantArray *InitList = cast<ConstantArray>(List);
1059  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
1060    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
1061      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
1062
1063      if (CS->getOperand(1)->isNullValue())
1064        return;  // Found a null terminator, exit printing.
1065      // Emit the function pointer.
1066      EmitGlobalConstant(CS->getOperand(1));
1067    }
1068}
1069
1070//===--------------------------------------------------------------------===//
1071// Emission and print routines
1072//
1073
1074/// EmitInt8 - Emit a byte directive and value.
1075///
1076void AsmPrinter::EmitInt8(int Value) const {
1077  OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
1078}
1079
1080/// EmitInt16 - Emit a short directive and value.
1081///
1082void AsmPrinter::EmitInt16(int Value) const {
1083  OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
1084}
1085
1086/// EmitInt32 - Emit a long directive and value.
1087///
1088void AsmPrinter::EmitInt32(int Value) const {
1089  OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
1090}
1091
1092/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1093/// in bytes of the directive is specified by Size and Hi/Lo specify the
1094/// labels.  This implicitly uses .set if it is available.
1095void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1096                                     unsigned Size) const {
1097  // Get the Hi-Lo expression.
1098  const MCExpr *Diff =
1099    MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1100                            MCSymbolRefExpr::Create(Lo, OutContext),
1101                            OutContext);
1102
1103  if (!MAI->hasSetDirective()) {
1104    OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
1105    return;
1106  }
1107
1108  // Otherwise, emit with .set (aka assignment).
1109  MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1110  OutStreamer.EmitAssignment(SetLabel, Diff);
1111  OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
1112}
1113
1114/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1115/// where the size in bytes of the directive is specified by Size and Hi/Lo
1116/// specify the labels.  This implicitly uses .set if it is available.
1117void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1118                                           const MCSymbol *Lo, unsigned Size)
1119  const {
1120
1121  // Emit Hi+Offset - Lo
1122  // Get the Hi+Offset expression.
1123  const MCExpr *Plus =
1124    MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1125                            MCConstantExpr::Create(Offset, OutContext),
1126                            OutContext);
1127
1128  // Get the Hi+Offset-Lo expression.
1129  const MCExpr *Diff =
1130    MCBinaryExpr::CreateSub(Plus,
1131                            MCSymbolRefExpr::Create(Lo, OutContext),
1132                            OutContext);
1133
1134  if (!MAI->hasSetDirective())
1135    OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
1136  else {
1137    // Otherwise, emit with .set (aka assignment).
1138    MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1139    OutStreamer.EmitAssignment(SetLabel, Diff);
1140    OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
1141  }
1142}
1143
1144
1145//===----------------------------------------------------------------------===//
1146
1147// EmitAlignment - Emit an alignment directive to the specified power of
1148// two boundary.  For example, if you pass in 3 here, you will get an 8
1149// byte alignment.  If a global value is specified, and if that global has
1150// an explicit alignment requested, it will unconditionally override the
1151// alignment request.  However, if ForcedAlignBits is specified, this value
1152// has final say: the ultimate alignment will be the max of ForcedAlignBits
1153// and the alignment computed with NumBits and the global.
1154//
1155// The algorithm is:
1156//     Align = NumBits;
1157//     if (GV && GV->hasalignment) Align = GV->getAlignment();
1158//
1159void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1160  if (GV && GV->getAlignment())
1161    NumBits = Log2_32(GV->getAlignment());
1162
1163  if (NumBits == 0) return;   // No need to emit alignment.
1164
1165  if (getCurrentSection()->getKind().isText())
1166    OutStreamer.EmitCodeAlignment(1 << NumBits);
1167  else
1168    OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
1169}
1170
1171//===----------------------------------------------------------------------===//
1172// Constant emission.
1173//===----------------------------------------------------------------------===//
1174
1175/// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
1176///
1177static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
1178  MCContext &Ctx = AP.OutContext;
1179
1180  if (CV->isNullValue() || isa<UndefValue>(CV))
1181    return MCConstantExpr::Create(0, Ctx);
1182
1183  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1184    return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1185
1186  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1187    return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
1188  if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1189    return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1190
1191  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1192  if (CE == 0) {
1193    llvm_unreachable("Unknown constant value to lower!");
1194    return MCConstantExpr::Create(0, Ctx);
1195  }
1196
1197  switch (CE->getOpcode()) {
1198  default:
1199    // If the code isn't optimized, there may be outstanding folding
1200    // opportunities. Attempt to fold the expression using TargetData as a
1201    // last resort before giving up.
1202    if (Constant *C =
1203          ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
1204      if (C != CE)
1205        return LowerConstant(C, AP);
1206#ifndef NDEBUG
1207    CE->dump();
1208#endif
1209    llvm_unreachable("FIXME: Don't support this constant expr");
1210  case Instruction::GetElementPtr: {
1211    const TargetData &TD = *AP.TM.getTargetData();
1212    // Generate a symbolic expression for the byte address
1213    const Constant *PtrVal = CE->getOperand(0);
1214    SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1215    int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1216                                         IdxVec.size());
1217
1218    const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1219    if (Offset == 0)
1220      return Base;
1221
1222    // Truncate/sext the offset to the pointer size.
1223    if (TD.getPointerSizeInBits() != 64) {
1224      int SExtAmount = 64-TD.getPointerSizeInBits();
1225      Offset = (Offset << SExtAmount) >> SExtAmount;
1226    }
1227
1228    return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1229                                   Ctx);
1230  }
1231
1232  case Instruction::Trunc:
1233    // We emit the value and depend on the assembler to truncate the generated
1234    // expression properly.  This is important for differences between
1235    // blockaddress labels.  Since the two labels are in the same function, it
1236    // is reasonable to treat their delta as a 32-bit value.
1237    // FALL THROUGH.
1238  case Instruction::BitCast:
1239    return LowerConstant(CE->getOperand(0), AP);
1240
1241  case Instruction::IntToPtr: {
1242    const TargetData &TD = *AP.TM.getTargetData();
1243    // Handle casts to pointers by changing them into casts to the appropriate
1244    // integer type.  This promotes constant folding and simplifies this code.
1245    Constant *Op = CE->getOperand(0);
1246    Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1247                                      false/*ZExt*/);
1248    return LowerConstant(Op, AP);
1249  }
1250
1251  case Instruction::PtrToInt: {
1252    const TargetData &TD = *AP.TM.getTargetData();
1253    // Support only foldable casts to/from pointers that can be eliminated by
1254    // changing the pointer to the appropriately sized integer type.
1255    Constant *Op = CE->getOperand(0);
1256    const Type *Ty = CE->getType();
1257
1258    const MCExpr *OpExpr = LowerConstant(Op, AP);
1259
1260    // We can emit the pointer value into this slot if the slot is an
1261    // integer slot equal to the size of the pointer.
1262    if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1263      return OpExpr;
1264
1265    // Otherwise the pointer is smaller than the resultant integer, mask off
1266    // the high bits so we are sure to get a proper truncation if the input is
1267    // a constant expr.
1268    unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1269    const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1270    return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1271  }
1272
1273  // The MC library also has a right-shift operator, but it isn't consistently
1274  // signed or unsigned between different targets.
1275  case Instruction::Add:
1276  case Instruction::Sub:
1277  case Instruction::Mul:
1278  case Instruction::SDiv:
1279  case Instruction::SRem:
1280  case Instruction::Shl:
1281  case Instruction::And:
1282  case Instruction::Or:
1283  case Instruction::Xor: {
1284    const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1285    const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1286    switch (CE->getOpcode()) {
1287    default: llvm_unreachable("Unknown binary operator constant cast expr");
1288    case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1289    case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1290    case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1291    case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1292    case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1293    case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1294    case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1295    case Instruction::Or:  return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1296    case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1297    }
1298  }
1299  }
1300}
1301
1302static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
1303                                   AsmPrinter &AP);
1304
1305static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1306                                    AsmPrinter &AP) {
1307  if (AddrSpace != 0 || !CA->isString()) {
1308    // Not a string.  Print the values in successive locations
1309    for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1310      EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
1311    return;
1312  }
1313
1314  // Otherwise, it can be emitted as .ascii.
1315  SmallVector<char, 128> TmpVec;
1316  TmpVec.reserve(CA->getNumOperands());
1317  for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1318    TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1319
1320  AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1321}
1322
1323static void EmitGlobalConstantVector(const ConstantVector *CV,
1324                                     unsigned AddrSpace, AsmPrinter &AP) {
1325  for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1326    EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
1327}
1328
1329static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1330                                     unsigned AddrSpace, AsmPrinter &AP) {
1331  // Print the fields in successive locations. Pad to align if needed!
1332  const TargetData *TD = AP.TM.getTargetData();
1333  unsigned Size = TD->getTypeAllocSize(CS->getType());
1334  const StructLayout *Layout = TD->getStructLayout(CS->getType());
1335  uint64_t SizeSoFar = 0;
1336  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1337    const Constant *Field = CS->getOperand(i);
1338
1339    // Check if padding is needed and insert one or more 0s.
1340    uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1341    uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1342                        - Layout->getElementOffset(i)) - FieldSize;
1343    SizeSoFar += FieldSize + PadSize;
1344
1345    // Now print the actual field value.
1346    EmitGlobalConstantImpl(Field, AddrSpace, AP);
1347
1348    // Insert padding - this may include padding to increase the size of the
1349    // current field up to the ABI size (if the struct is not packed) as well
1350    // as padding to ensure that the next field starts at the right offset.
1351    AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1352  }
1353  assert(SizeSoFar == Layout->getSizeInBytes() &&
1354         "Layout of constant struct may be incorrect!");
1355}
1356
1357static void EmitGlobalConstantUnion(const ConstantUnion *CU,
1358                                    unsigned AddrSpace, AsmPrinter &AP) {
1359  const TargetData *TD = AP.TM.getTargetData();
1360  unsigned Size = TD->getTypeAllocSize(CU->getType());
1361
1362  const Constant *Contents = CU->getOperand(0);
1363  unsigned FilledSize = TD->getTypeAllocSize(Contents->getType());
1364
1365  // Print the actually filled part
1366  EmitGlobalConstantImpl(Contents, AddrSpace, AP);
1367
1368  // And pad with enough zeroes
1369  AP.OutStreamer.EmitZeros(Size-FilledSize, AddrSpace);
1370}
1371
1372static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1373                                 AsmPrinter &AP) {
1374  // FP Constants are printed as integer constants to avoid losing
1375  // precision.
1376  if (CFP->getType()->isDoubleTy()) {
1377    if (AP.isVerbose()) {
1378      double Val = CFP->getValueAPF().convertToDouble();
1379      AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1380    }
1381
1382    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1383    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1384    return;
1385  }
1386
1387  if (CFP->getType()->isFloatTy()) {
1388    if (AP.isVerbose()) {
1389      float Val = CFP->getValueAPF().convertToFloat();
1390      AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1391    }
1392    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1393    AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1394    return;
1395  }
1396
1397  if (CFP->getType()->isX86_FP80Ty()) {
1398    // all long double variants are printed as hex
1399    // API needed to prevent premature destruction
1400    APInt API = CFP->getValueAPF().bitcastToAPInt();
1401    const uint64_t *p = API.getRawData();
1402    if (AP.isVerbose()) {
1403      // Convert to double so we can print the approximate val as a comment.
1404      APFloat DoubleVal = CFP->getValueAPF();
1405      bool ignored;
1406      DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1407                        &ignored);
1408      AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1409        << DoubleVal.convertToDouble() << '\n';
1410    }
1411
1412    if (AP.TM.getTargetData()->isBigEndian()) {
1413      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1414      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1415    } else {
1416      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1417      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1418    }
1419
1420    // Emit the tail padding for the long double.
1421    const TargetData &TD = *AP.TM.getTargetData();
1422    AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1423                             TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1424    return;
1425  }
1426
1427  assert(CFP->getType()->isPPC_FP128Ty() &&
1428         "Floating point constant type not handled");
1429  // All long double variants are printed as hex
1430  // API needed to prevent premature destruction.
1431  APInt API = CFP->getValueAPF().bitcastToAPInt();
1432  const uint64_t *p = API.getRawData();
1433  if (AP.TM.getTargetData()->isBigEndian()) {
1434    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1435    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1436  } else {
1437    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1438    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1439  }
1440}
1441
1442static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1443                                       unsigned AddrSpace, AsmPrinter &AP) {
1444  const TargetData *TD = AP.TM.getTargetData();
1445  unsigned BitWidth = CI->getBitWidth();
1446  assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1447
1448  // We don't expect assemblers to support integer data directives
1449  // for more than 64 bits, so we emit the data in at most 64-bit
1450  // quantities at a time.
1451  const uint64_t *RawData = CI->getValue().getRawData();
1452  for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1453    uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1454    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1455  }
1456}
1457
1458static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
1459                                   AsmPrinter &AP) {
1460  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1461    uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1462    return AP.OutStreamer.EmitZeros(Size, AddrSpace);
1463  }
1464
1465  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1466    unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1467    switch (Size) {
1468    case 1:
1469    case 2:
1470    case 4:
1471    case 8:
1472      if (AP.isVerbose())
1473        AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1474        AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1475      return;
1476    default:
1477      EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
1478      return;
1479    }
1480  }
1481
1482  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1483    return EmitGlobalConstantArray(CVA, AddrSpace, AP);
1484
1485  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1486    return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
1487
1488  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1489    return EmitGlobalConstantFP(CFP, AddrSpace, AP);
1490
1491  if (isa<ConstantPointerNull>(CV)) {
1492    unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
1493    AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
1494    return;
1495  }
1496
1497  if (const ConstantUnion *CVU = dyn_cast<ConstantUnion>(CV))
1498    return EmitGlobalConstantUnion(CVU, AddrSpace, AP);
1499
1500  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1501    return EmitGlobalConstantVector(V, AddrSpace, AP);
1502
1503  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
1504  // thread the streamer with EmitValue.
1505  AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
1506                         AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
1507                           AddrSpace);
1508}
1509
1510/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1511void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1512  uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1513  if (Size)
1514    EmitGlobalConstantImpl(CV, AddrSpace, *this);
1515  else if (MAI->hasSubsectionsViaSymbols()) {
1516    // If the global has zero size, emit a single byte so that two labels don't
1517    // look like they are at the same location.
1518    OutStreamer.EmitIntValue(0, 1, AddrSpace);
1519  }
1520}
1521
1522void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1523  // Target doesn't support this yet!
1524  llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1525}
1526
1527void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
1528  if (Offset > 0)
1529    OS << '+' << Offset;
1530  else if (Offset < 0)
1531    OS << Offset;
1532}
1533
1534//===----------------------------------------------------------------------===//
1535// Symbol Lowering Routines.
1536//===----------------------------------------------------------------------===//
1537
1538/// GetTempSymbol - Return the MCSymbol corresponding to the assembler
1539/// temporary label with the specified stem and unique ID.
1540MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
1541  return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
1542                                      Name + Twine(ID));
1543}
1544
1545/// GetTempSymbol - Return an assembler temporary label with the specified
1546/// stem.
1547MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
1548  return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
1549                                      Name);
1550}
1551
1552
1553MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1554  return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1555}
1556
1557MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1558  return MMI->getAddrLabelSymbol(BB);
1559}
1560
1561/// GetCPISymbol - Return the symbol for the specified constant pool entry.
1562MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1563  return OutContext.GetOrCreateSymbol
1564    (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1565     + "_" + Twine(CPID));
1566}
1567
1568/// GetJTISymbol - Return the symbol for the specified jump table entry.
1569MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1570  return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1571}
1572
1573/// GetJTSetSymbol - Return the symbol for the specified jump table .set
1574/// FIXME: privatize to AsmPrinter.
1575MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1576  return OutContext.GetOrCreateSymbol
1577  (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1578   Twine(UID) + "_set_" + Twine(MBBID));
1579}
1580
1581/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1582/// global value name as its base, with the specified suffix, and where the
1583/// symbol is forced to have private linkage if ForcePrivate is true.
1584MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1585                                                   StringRef Suffix,
1586                                                   bool ForcePrivate) const {
1587  SmallString<60> NameStr;
1588  Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1589  NameStr.append(Suffix.begin(), Suffix.end());
1590  return OutContext.GetOrCreateSymbol(NameStr.str());
1591}
1592
1593/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1594/// ExternalSymbol.
1595MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1596  SmallString<60> NameStr;
1597  Mang->getNameWithPrefix(NameStr, Sym);
1598  return OutContext.GetOrCreateSymbol(NameStr.str());
1599}
1600
1601
1602
1603/// PrintParentLoopComment - Print comments about parent loops of this one.
1604static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1605                                   unsigned FunctionNumber) {
1606  if (Loop == 0) return;
1607  PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1608  OS.indent(Loop->getLoopDepth()*2)
1609    << "Parent Loop BB" << FunctionNumber << "_"
1610    << Loop->getHeader()->getNumber()
1611    << " Depth=" << Loop->getLoopDepth() << '\n';
1612}
1613
1614
1615/// PrintChildLoopComment - Print comments about child loops within
1616/// the loop for this basic block, with nesting.
1617static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1618                                  unsigned FunctionNumber) {
1619  // Add child loop information
1620  for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1621    OS.indent((*CL)->getLoopDepth()*2)
1622      << "Child Loop BB" << FunctionNumber << "_"
1623      << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1624      << '\n';
1625    PrintChildLoopComment(OS, *CL, FunctionNumber);
1626  }
1627}
1628
1629/// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
1630static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
1631                                       const MachineLoopInfo *LI,
1632                                       const AsmPrinter &AP) {
1633  // Add loop depth information
1634  const MachineLoop *Loop = LI->getLoopFor(&MBB);
1635  if (Loop == 0) return;
1636
1637  MachineBasicBlock *Header = Loop->getHeader();
1638  assert(Header && "No header for loop");
1639
1640  // If this block is not a loop header, just print out what is the loop header
1641  // and return.
1642  if (Header != &MBB) {
1643    AP.OutStreamer.AddComment("  in Loop: Header=BB" +
1644                              Twine(AP.getFunctionNumber())+"_" +
1645                              Twine(Loop->getHeader()->getNumber())+
1646                              " Depth="+Twine(Loop->getLoopDepth()));
1647    return;
1648  }
1649
1650  // Otherwise, it is a loop header.  Print out information about child and
1651  // parent loops.
1652  raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1653
1654  PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1655
1656  OS << "=>";
1657  OS.indent(Loop->getLoopDepth()*2-2);
1658
1659  OS << "This ";
1660  if (Loop->empty())
1661    OS << "Inner ";
1662  OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1663
1664  PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1665}
1666
1667
1668/// EmitBasicBlockStart - This method prints the label for the specified
1669/// MachineBasicBlock, an alignment (if present) and a comment describing
1670/// it if appropriate.
1671void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1672  // Emit an alignment directive for this block, if needed.
1673  if (unsigned Align = MBB->getAlignment())
1674    EmitAlignment(Log2_32(Align));
1675
1676  // If the block has its address taken, emit any labels that were used to
1677  // reference the block.  It is possible that there is more than one label
1678  // here, because multiple LLVM BB's may have been RAUW'd to this block after
1679  // the references were generated.
1680  if (MBB->hasAddressTaken()) {
1681    const BasicBlock *BB = MBB->getBasicBlock();
1682    if (isVerbose())
1683      OutStreamer.AddComment("Block address taken");
1684
1685    std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1686
1687    for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1688      OutStreamer.EmitLabel(Syms[i]);
1689  }
1690
1691  // Print the main label for the block.
1692  if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1693    if (isVerbose() && OutStreamer.hasRawTextSupport()) {
1694      if (const BasicBlock *BB = MBB->getBasicBlock())
1695        if (BB->hasName())
1696          OutStreamer.AddComment("%" + BB->getName());
1697
1698      EmitBasicBlockLoopComments(*MBB, LI, *this);
1699
1700      // NOTE: Want this comment at start of line, don't emit with AddComment.
1701      OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
1702                              Twine(MBB->getNumber()) + ":");
1703    }
1704  } else {
1705    if (isVerbose()) {
1706      if (const BasicBlock *BB = MBB->getBasicBlock())
1707        if (BB->hasName())
1708          OutStreamer.AddComment("%" + BB->getName());
1709      EmitBasicBlockLoopComments(*MBB, LI, *this);
1710    }
1711
1712    OutStreamer.EmitLabel(MBB->getSymbol());
1713  }
1714}
1715
1716void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1717  MCSymbolAttr Attr = MCSA_Invalid;
1718
1719  switch (Visibility) {
1720  default: break;
1721  case GlobalValue::HiddenVisibility:
1722    Attr = MAI->getHiddenVisibilityAttr();
1723    break;
1724  case GlobalValue::ProtectedVisibility:
1725    Attr = MAI->getProtectedVisibilityAttr();
1726    break;
1727  }
1728
1729  if (Attr != MCSA_Invalid)
1730    OutStreamer.EmitSymbolAttribute(Sym, Attr);
1731}
1732
1733/// isBlockOnlyReachableByFallthough - Return true if the basic block has
1734/// exactly one predecessor and the control transfer mechanism between
1735/// the predecessor and this block is a fall-through.
1736bool AsmPrinter::
1737isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
1738  // If this is a landing pad, it isn't a fall through.  If it has no preds,
1739  // then nothing falls through to it.
1740  if (MBB->isLandingPad() || MBB->pred_empty())
1741    return false;
1742
1743  // If there isn't exactly one predecessor, it can't be a fall through.
1744  MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1745  ++PI2;
1746  if (PI2 != MBB->pred_end())
1747    return false;
1748
1749  // The predecessor has to be immediately before this block.
1750  const MachineBasicBlock *Pred = *PI;
1751
1752  if (!Pred->isLayoutSuccessor(MBB))
1753    return false;
1754
1755  // If the block is completely empty, then it definitely does fall through.
1756  if (Pred->empty())
1757    return true;
1758
1759  // Otherwise, check the last instruction.
1760  const MachineInstr &LastInst = Pred->back();
1761  return !LastInst.getDesc().isBarrier();
1762}
1763
1764
1765
1766GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1767  if (!S->usesMetadata())
1768    return 0;
1769
1770  gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
1771  gcp_map_type::iterator GCPI = GCMap.find(S);
1772  if (GCPI != GCMap.end())
1773    return GCPI->second;
1774
1775  const char *Name = S->getName().c_str();
1776
1777  for (GCMetadataPrinterRegistry::iterator
1778         I = GCMetadataPrinterRegistry::begin(),
1779         E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1780    if (strcmp(Name, I->getName()) == 0) {
1781      GCMetadataPrinter *GMP = I->instantiate();
1782      GMP->S = S;
1783      GCMap.insert(std::make_pair(S, GMP));
1784      return GMP;
1785    }
1786
1787  report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
1788  return 0;
1789}
1790
1791