AsmPrinter.cpp revision be149874dbf1f1a139afb106da91d617025964eb 
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 "llvm/Assembly/Writer.h"
17#include "llvm/DerivedTypes.h"
18#include "llvm/Constants.h"
19#include "llvm/Module.h"
20#include "llvm/CodeGen/DwarfWriter.h"
21#include "llvm/CodeGen/GCMetadataPrinter.h"
22#include "llvm/CodeGen/MachineConstantPool.h"
23#include "llvm/CodeGen/MachineFrameInfo.h"
24#include "llvm/CodeGen/MachineFunction.h"
25#include "llvm/CodeGen/MachineJumpTableInfo.h"
26#include "llvm/CodeGen/MachineLoopInfo.h"
27#include "llvm/CodeGen/MachineModuleInfo.h"
28#include "llvm/Analysis/ConstantFolding.h"
29#include "llvm/Analysis/DebugInfo.h"
30#include "llvm/MC/MCContext.h"
31#include "llvm/MC/MCExpr.h"
32#include "llvm/MC/MCInst.h"
33#include "llvm/MC/MCSection.h"
34#include "llvm/MC/MCStreamer.h"
35#include "llvm/MC/MCSymbol.h"
36#include "llvm/MC/MCAsmInfo.h"
37#include "llvm/Target/Mangler.h"
38#include "llvm/Target/TargetData.h"
39#include "llvm/Target/TargetInstrInfo.h"
40#include "llvm/Target/TargetLowering.h"
41#include "llvm/Target/TargetLoweringObjectFile.h"
42#include "llvm/Target/TargetOptions.h"
43#include "llvm/Target/TargetRegisterInfo.h"
44#include "llvm/ADT/SmallPtrSet.h"
45#include "llvm/ADT/SmallString.h"
46#include "llvm/ADT/Statistic.h"
47#include "llvm/Support/CommandLine.h"
48#include "llvm/Support/Debug.h"
49#include "llvm/Support/ErrorHandling.h"
50#include "llvm/Support/Format.h"
51#include "llvm/Support/FormattedStream.h"
52#include <cerrno>
53using namespace llvm;
54
55STATISTIC(EmittedInsts, "Number of machine instrs printed");
56
57char AsmPrinter::ID = 0;
58AsmPrinter::AsmPrinter(formatted_raw_ostream &o, TargetMachine &tm,
59                       MCContext &Ctx, MCStreamer &Streamer,
60                       const MCAsmInfo *T)
61  : MachineFunctionPass(&ID), O(o),
62    TM(tm), MAI(T), TRI(tm.getRegisterInfo()),
63    OutContext(Ctx), OutStreamer(Streamer),
64    LastMI(0), LastFn(0), Counter(~0U), PrevDLT(NULL) {
65  DW = 0; MMI = 0;
66  VerboseAsm = Streamer.isVerboseAsm();
67}
68
69AsmPrinter::~AsmPrinter() {
70  for (gcp_iterator I = GCMetadataPrinters.begin(),
71                    E = GCMetadataPrinters.end(); I != E; ++I)
72    delete I->second;
73
74  delete &OutStreamer;
75  delete &OutContext;
76}
77
78/// getFunctionNumber - Return a unique ID for the current function.
79///
80unsigned AsmPrinter::getFunctionNumber() const {
81  return MF->getFunctionNumber();
82}
83
84TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
85  return TM.getTargetLowering()->getObjFileLowering();
86}
87
88/// getCurrentSection() - Return the current section we are emitting to.
89const MCSection *AsmPrinter::getCurrentSection() const {
90  return OutStreamer.getCurrentSection();
91}
92
93
94void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
95  AU.setPreservesAll();
96  MachineFunctionPass::getAnalysisUsage(AU);
97  AU.addRequired<GCModuleInfo>();
98  if (VerboseAsm)
99    AU.addRequired<MachineLoopInfo>();
100}
101
102bool AsmPrinter::doInitialization(Module &M) {
103  // Initialize TargetLoweringObjectFile.
104  const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
105    .Initialize(OutContext, TM);
106
107  Mang = new Mangler(*MAI);
108
109  // Allow the target to emit any magic that it wants at the start of the file.
110  EmitStartOfAsmFile(M);
111
112  // Very minimal debug info. It is ignored if we emit actual debug info. If we
113  // don't, this at least helps the user find where a global came from.
114  if (MAI->hasSingleParameterDotFile()) {
115    // .file "foo.c"
116    OutStreamer.EmitFileDirective(M.getModuleIdentifier());
117  }
118
119  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
120  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
121  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
122    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
123      MP->beginAssembly(O, *this, *MAI);
124
125  if (!M.getModuleInlineAsm().empty())
126    O << MAI->getCommentString() << " Start of file scope inline assembly\n"
127      << M.getModuleInlineAsm()
128      << '\n' << MAI->getCommentString()
129      << " End of file scope inline assembly\n";
130
131  MMI = getAnalysisIfAvailable<MachineModuleInfo>();
132  if (MMI)
133    MMI->AnalyzeModule(M);
134  DW = getAnalysisIfAvailable<DwarfWriter>();
135  if (DW)
136    DW->BeginModule(&M, MMI, O, this, MAI);
137
138  return false;
139}
140
141void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
142  switch ((GlobalValue::LinkageTypes)Linkage) {
143  case GlobalValue::CommonLinkage:
144  case GlobalValue::LinkOnceAnyLinkage:
145  case GlobalValue::LinkOnceODRLinkage:
146  case GlobalValue::WeakAnyLinkage:
147  case GlobalValue::WeakODRLinkage:
148  case GlobalValue::LinkerPrivateLinkage:
149    if (MAI->getWeakDefDirective() != 0) {
150      // .globl _foo
151      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
152      // .weak_definition _foo
153      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
154    } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) {
155      // .globl _foo
156      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
157      // FIXME: linkonce should be a section attribute, handled by COFF Section
158      // assignment.
159      // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce
160      // .linkonce discard
161      // FIXME: It would be nice to use .linkonce samesize for non-common
162      // globals.
163      O << LinkOnce;
164    } else {
165      // .weak _foo
166      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
167    }
168    break;
169  case GlobalValue::DLLExportLinkage:
170  case GlobalValue::AppendingLinkage:
171    // FIXME: appending linkage variables should go into a section of
172    // their name or something.  For now, just emit them as external.
173  case GlobalValue::ExternalLinkage:
174    // If external or appending, declare as a global symbol.
175    // .globl _foo
176    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
177    break;
178  case GlobalValue::PrivateLinkage:
179  case GlobalValue::InternalLinkage:
180    break;
181  default:
182    llvm_unreachable("Unknown linkage type!");
183  }
184}
185
186
187/// EmitGlobalVariable - Emit the specified global variable to the .s file.
188void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
189  if (!GV->hasInitializer())   // External globals require no code.
190    return;
191
192  // Check to see if this is a special global used by LLVM, if so, emit it.
193  if (EmitSpecialLLVMGlobal(GV))
194    return;
195
196  MCSymbol *GVSym = GetGlobalValueSymbol(GV);
197  EmitVisibility(GVSym, GV->getVisibility());
198
199  if (MAI->hasDotTypeDotSizeDirective())
200    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
201
202  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
203
204  const TargetData *TD = TM.getTargetData();
205  unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType());
206  unsigned AlignLog = TD->getPreferredAlignmentLog(GV);
207
208  // Handle common and BSS local symbols (.lcomm).
209  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
210    if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
211
212    if (VerboseAsm) {
213      WriteAsOperand(OutStreamer.GetCommentOS(), GV,
214                     /*PrintType=*/false, GV->getParent());
215      OutStreamer.GetCommentOS() << '\n';
216    }
217
218    // Handle common symbols.
219    if (GVKind.isCommon()) {
220      // .comm _foo, 42, 4
221      OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
222      return;
223    }
224
225    // Handle local BSS symbols.
226    if (MAI->hasMachoZeroFillDirective()) {
227      const MCSection *TheSection =
228        getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
229      // .zerofill __DATA, __bss, _foo, 400, 5
230      OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
231      return;
232    }
233
234    if (MAI->hasLCOMMDirective()) {
235      // .lcomm _foo, 42
236      OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
237      return;
238    }
239
240    // .local _foo
241    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
242    // .comm _foo, 42, 4
243    OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
244    return;
245  }
246
247  const MCSection *TheSection =
248    getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
249
250  // Handle the zerofill directive on darwin, which is a special form of BSS
251  // emission.
252  if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
253    // .globl _foo
254    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
255    // .zerofill __DATA, __common, _foo, 400, 5
256    OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
257    return;
258  }
259
260  OutStreamer.SwitchSection(TheSection);
261
262  EmitLinkage(GV->getLinkage(), GVSym);
263  EmitAlignment(AlignLog, GV);
264
265  if (VerboseAsm) {
266    WriteAsOperand(OutStreamer.GetCommentOS(), GV,
267                   /*PrintType=*/false, GV->getParent());
268    OutStreamer.GetCommentOS() << '\n';
269  }
270  OutStreamer.EmitLabel(GVSym);
271
272  EmitGlobalConstant(GV->getInitializer());
273
274  if (MAI->hasDotTypeDotSizeDirective())
275    // .size foo, 42
276    OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
277
278  OutStreamer.AddBlankLine();
279}
280
281/// EmitFunctionHeader - This method emits the header for the current
282/// function.
283void AsmPrinter::EmitFunctionHeader() {
284  // Print out constants referenced by the function
285  EmitConstantPool();
286
287  // Print the 'header' of function.
288  const Function *F = MF->getFunction();
289
290  OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
291  EmitVisibility(CurrentFnSym, F->getVisibility());
292
293  EmitLinkage(F->getLinkage(), CurrentFnSym);
294  EmitAlignment(MF->getAlignment(), F);
295
296  if (MAI->hasDotTypeDotSizeDirective())
297    OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
298
299  if (VerboseAsm) {
300    WriteAsOperand(OutStreamer.GetCommentOS(), F,
301                   /*PrintType=*/false, F->getParent());
302    OutStreamer.GetCommentOS() << '\n';
303  }
304
305  // Emit the CurrentFnSym.  This is a virtual function to allow targets to
306  // do their wild and crazy things as required.
307  EmitFunctionEntryLabel();
308
309  // Add some workaround for linkonce linkage on Cygwin\MinGW.
310  if (MAI->getLinkOnceDirective() != 0 &&
311      (F->hasLinkOnceLinkage() || F->hasWeakLinkage()))
312    // FIXME: What is this?
313    O << "Lllvm$workaround$fake$stub$" << *CurrentFnSym << ":\n";
314
315  // Emit pre-function debug and/or EH information.
316  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
317    DW->BeginFunction(MF);
318}
319
320/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
321/// function.  This can be overridden by targets as required to do custom stuff.
322void AsmPrinter::EmitFunctionEntryLabel() {
323  OutStreamer.EmitLabel(CurrentFnSym);
324}
325
326
327/// EmitComments - Pretty-print comments for instructions.
328static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
329  const MachineFunction *MF = MI.getParent()->getParent();
330  const TargetMachine &TM = MF->getTarget();
331
332  if (!MI.getDebugLoc().isUnknown()) {
333    DILocation DLT = MF->getDILocation(MI.getDebugLoc());
334
335    // Print source line info.
336    DIScope Scope = DLT.getScope();
337    // Omit the directory, because it's likely to be long and uninteresting.
338    if (!Scope.isNull())
339      CommentOS << Scope.getFilename();
340    else
341      CommentOS << "<unknown>";
342    CommentOS << ':' << DLT.getLineNumber();
343    if (DLT.getColumnNumber() != 0)
344      CommentOS << ':' << DLT.getColumnNumber();
345    CommentOS << '\n';
346  }
347
348  // Check for spills and reloads
349  int FI;
350
351  const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
352
353  // We assume a single instruction only has a spill or reload, not
354  // both.
355  const MachineMemOperand *MMO;
356  if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
357    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
358      MMO = *MI.memoperands_begin();
359      CommentOS << MMO->getSize() << "-byte Reload\n";
360    }
361  } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
362    if (FrameInfo->isSpillSlotObjectIndex(FI))
363      CommentOS << MMO->getSize() << "-byte Folded Reload\n";
364  } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
365    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
366      MMO = *MI.memoperands_begin();
367      CommentOS << MMO->getSize() << "-byte Spill\n";
368    }
369  } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
370    if (FrameInfo->isSpillSlotObjectIndex(FI))
371      CommentOS << MMO->getSize() << "-byte Folded Spill\n";
372  }
373
374  // Check for spill-induced copies
375  unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
376  if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
377                                     SrcSubIdx, DstSubIdx)) {
378    if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
379      CommentOS << " Reload Reuse\n";
380  }
381}
382
383
384
385/// EmitFunctionBody - This method emits the body and trailer for a
386/// function.
387void AsmPrinter::EmitFunctionBody() {
388  // Emit target-specific gunk before the function body.
389  EmitFunctionBodyStart();
390
391  // Print out code for the function.
392  bool HasAnyRealCode = false;
393  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
394       I != E; ++I) {
395    // Print a label for the basic block.
396    EmitBasicBlockStart(I);
397    for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
398         II != IE; ++II) {
399      // Print the assembly for the instruction.
400      if (!II->isLabel())
401        HasAnyRealCode = true;
402
403      ++EmittedInsts;
404
405      // FIXME: Clean up processDebugLoc.
406      processDebugLoc(II, true);
407
408      if (VerboseAsm)
409        EmitComments(*II, OutStreamer.GetCommentOS());
410
411      switch (II->getOpcode()) {
412      case TargetOpcode::DBG_LABEL:
413      case TargetOpcode::EH_LABEL:
414      case TargetOpcode::GC_LABEL:
415        printLabelInst(II);
416        break;
417      case TargetOpcode::INLINEASM:
418        printInlineAsm(II);
419        break;
420      case TargetOpcode::IMPLICIT_DEF:
421        printImplicitDef(II);
422        break;
423      case TargetOpcode::KILL:
424        printKill(II);
425        break;
426      default:
427        EmitInstruction(II);
428        break;
429      }
430
431      // FIXME: Clean up processDebugLoc.
432      processDebugLoc(II, false);
433    }
434  }
435
436  // If the function is empty and the object file uses .subsections_via_symbols,
437  // then we need to emit *something* to the function body to prevent the
438  // labels from collapsing together.  Just emit a 0 byte.
439  if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)
440    OutStreamer.EmitIntValue(0, 1, 0/*addrspace*/);
441
442  // Emit target-specific gunk after the function body.
443  EmitFunctionBodyEnd();
444
445  if (MAI->hasDotTypeDotSizeDirective())
446    O << "\t.size\t" << *CurrentFnSym << ", .-" << *CurrentFnSym << '\n';
447
448  // Emit post-function debug information.
449  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
450    DW->EndFunction(MF);
451
452  // Print out jump tables referenced by the function.
453  EmitJumpTableInfo();
454
455  OutStreamer.AddBlankLine();
456}
457
458
459bool AsmPrinter::doFinalization(Module &M) {
460  // Emit global variables.
461  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
462       I != E; ++I)
463    EmitGlobalVariable(I);
464
465  // Emit final debug information.
466  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
467    DW->EndModule();
468
469  // If the target wants to know about weak references, print them all.
470  if (MAI->getWeakRefDirective()) {
471    // FIXME: This is not lazy, it would be nice to only print weak references
472    // to stuff that is actually used.  Note that doing so would require targets
473    // to notice uses in operands (due to constant exprs etc).  This should
474    // happen with the MC stuff eventually.
475
476    // Print out module-level global variables here.
477    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
478         I != E; ++I) {
479      if (!I->hasExternalWeakLinkage()) continue;
480      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(I),
481                                      MCSA_WeakReference);
482    }
483
484    for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
485      if (!I->hasExternalWeakLinkage()) continue;
486      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(I),
487                                      MCSA_WeakReference);
488    }
489  }
490
491  if (MAI->hasSetDirective()) {
492    OutStreamer.AddBlankLine();
493    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
494         I != E; ++I) {
495      MCSymbol *Name = GetGlobalValueSymbol(I);
496
497      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
498      MCSymbol *Target = GetGlobalValueSymbol(GV);
499
500      if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
501        OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
502      else if (I->hasWeakLinkage())
503        OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
504      else
505        assert(I->hasLocalLinkage() && "Invalid alias linkage");
506
507      EmitVisibility(Name, I->getVisibility());
508
509      // Emit the directives as assignments aka .set:
510      OutStreamer.EmitAssignment(Name,
511                                 MCSymbolRefExpr::Create(Target, OutContext));
512    }
513  }
514
515  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
516  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
517  for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
518    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
519      MP->finishAssembly(O, *this, *MAI);
520
521  // If we don't have any trampolines, then we don't require stack memory
522  // to be executable. Some targets have a directive to declare this.
523  Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
524  if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
525    if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
526      OutStreamer.SwitchSection(S);
527
528  // Allow the target to emit any magic that it wants at the end of the file,
529  // after everything else has gone out.
530  EmitEndOfAsmFile(M);
531
532  delete Mang; Mang = 0;
533  DW = 0; MMI = 0;
534
535  OutStreamer.Finish();
536  return false;
537}
538
539void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
540  this->MF = &MF;
541  // Get the function symbol.
542  CurrentFnSym = GetGlobalValueSymbol(MF.getFunction());
543
544  if (VerboseAsm)
545    LI = &getAnalysis<MachineLoopInfo>();
546}
547
548namespace {
549  // SectionCPs - Keep track the alignment, constpool entries per Section.
550  struct SectionCPs {
551    const MCSection *S;
552    unsigned Alignment;
553    SmallVector<unsigned, 4> CPEs;
554    SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
555  };
556}
557
558/// EmitConstantPool - Print to the current output stream assembly
559/// representations of the constants in the constant pool MCP. This is
560/// used to print out constants which have been "spilled to memory" by
561/// the code generator.
562///
563void AsmPrinter::EmitConstantPool() {
564  const MachineConstantPool *MCP = MF->getConstantPool();
565  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
566  if (CP.empty()) return;
567
568  // Calculate sections for constant pool entries. We collect entries to go into
569  // the same section together to reduce amount of section switch statements.
570  SmallVector<SectionCPs, 4> CPSections;
571  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
572    const MachineConstantPoolEntry &CPE = CP[i];
573    unsigned Align = CPE.getAlignment();
574
575    SectionKind Kind;
576    switch (CPE.getRelocationInfo()) {
577    default: llvm_unreachable("Unknown section kind");
578    case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
579    case 1:
580      Kind = SectionKind::getReadOnlyWithRelLocal();
581      break;
582    case 0:
583    switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
584    case 4:  Kind = SectionKind::getMergeableConst4(); break;
585    case 8:  Kind = SectionKind::getMergeableConst8(); break;
586    case 16: Kind = SectionKind::getMergeableConst16();break;
587    default: Kind = SectionKind::getMergeableConst(); break;
588    }
589    }
590
591    const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
592
593    // The number of sections are small, just do a linear search from the
594    // last section to the first.
595    bool Found = false;
596    unsigned SecIdx = CPSections.size();
597    while (SecIdx != 0) {
598      if (CPSections[--SecIdx].S == S) {
599        Found = true;
600        break;
601      }
602    }
603    if (!Found) {
604      SecIdx = CPSections.size();
605      CPSections.push_back(SectionCPs(S, Align));
606    }
607
608    if (Align > CPSections[SecIdx].Alignment)
609      CPSections[SecIdx].Alignment = Align;
610    CPSections[SecIdx].CPEs.push_back(i);
611  }
612
613  // Now print stuff into the calculated sections.
614  for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
615    OutStreamer.SwitchSection(CPSections[i].S);
616    EmitAlignment(Log2_32(CPSections[i].Alignment));
617
618    unsigned Offset = 0;
619    for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
620      unsigned CPI = CPSections[i].CPEs[j];
621      MachineConstantPoolEntry CPE = CP[CPI];
622
623      // Emit inter-object padding for alignment.
624      unsigned AlignMask = CPE.getAlignment() - 1;
625      unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
626      OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
627
628      const Type *Ty = CPE.getType();
629      Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
630
631      // Emit the label with a comment on it.
632      if (VerboseAsm) {
633        OutStreamer.GetCommentOS() << "constant pool ";
634        WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
635                          MF->getFunction()->getParent());
636        OutStreamer.GetCommentOS() << '\n';
637      }
638      OutStreamer.EmitLabel(GetCPISymbol(CPI));
639
640      if (CPE.isMachineConstantPoolEntry())
641        EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
642      else
643        EmitGlobalConstant(CPE.Val.ConstVal);
644    }
645  }
646}
647
648/// EmitJumpTableInfo - Print assembly representations of the jump tables used
649/// by the current function to the current output stream.
650///
651void AsmPrinter::EmitJumpTableInfo() {
652  const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
653  if (MJTI == 0) return;
654  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
655  if (JT.empty()) return;
656
657  // Pick the directive to use to print the jump table entries, and switch to
658  // the appropriate section.
659  const Function *F = MF->getFunction();
660  bool JTInDiffSection = false;
661  if (// In PIC mode, we need to emit the jump table to the same section as the
662      // function body itself, otherwise the label differences won't make sense.
663      // FIXME: Need a better predicate for this: what about custom entries?
664      MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
665      // We should also do if the section name is NULL or function is declared
666      // in discardable section
667      // FIXME: this isn't the right predicate, should be based on the MCSection
668      // for the function.
669      F->isWeakForLinker()) {
670    OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
671  } else {
672    // Otherwise, drop it in the readonly section.
673    const MCSection *ReadOnlySection =
674      getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
675    OutStreamer.SwitchSection(ReadOnlySection);
676    JTInDiffSection = true;
677  }
678
679  EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
680
681  for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
682    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
683
684    // If this jump table was deleted, ignore it.
685    if (JTBBs.empty()) continue;
686
687    // For the EK_LabelDifference32 entry, if the target supports .set, emit a
688    // .set directive for each unique entry.  This reduces the number of
689    // relocations the assembler will generate for the jump table.
690    if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
691        MAI->hasSetDirective()) {
692      SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
693      const TargetLowering *TLI = TM.getTargetLowering();
694      const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
695      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
696        const MachineBasicBlock *MBB = JTBBs[ii];
697        if (!EmittedSets.insert(MBB)) continue;
698
699        // .set LJTSet, LBB32-base
700        const MCExpr *LHS =
701          MCSymbolRefExpr::Create(MBB->getSymbol(OutContext), OutContext);
702        OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
703                                MCBinaryExpr::CreateSub(LHS, Base, OutContext));
704      }
705    }
706
707    // On some targets (e.g. Darwin) we want to emit two consequtive labels
708    // before each jump table.  The first label is never referenced, but tells
709    // the assembler and linker the extents of the jump table object.  The
710    // second label is actually referenced by the code.
711    if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
712      // FIXME: This doesn't have to have any specific name, just any randomly
713      // named and numbered 'l' label would work.  Simplify GetJTISymbol.
714      OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
715
716    OutStreamer.EmitLabel(GetJTISymbol(JTI));
717
718    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
719      EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
720  }
721}
722
723/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
724/// current stream.
725void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
726                                    const MachineBasicBlock *MBB,
727                                    unsigned UID) const {
728  const MCExpr *Value = 0;
729  switch (MJTI->getEntryKind()) {
730  case MachineJumpTableInfo::EK_Custom32:
731    Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
732                                                              OutContext);
733    break;
734  case MachineJumpTableInfo::EK_BlockAddress:
735    // EK_BlockAddress - Each entry is a plain address of block, e.g.:
736    //     .word LBB123
737    Value = MCSymbolRefExpr::Create(MBB->getSymbol(OutContext), OutContext);
738    break;
739  case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
740    // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
741    // with a relocation as gp-relative, e.g.:
742    //     .gprel32 LBB123
743    MCSymbol *MBBSym = MBB->getSymbol(OutContext);
744    OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
745    return;
746  }
747
748  case MachineJumpTableInfo::EK_LabelDifference32: {
749    // EK_LabelDifference32 - Each entry is the address of the block minus
750    // the address of the jump table.  This is used for PIC jump tables where
751    // gprel32 is not supported.  e.g.:
752    //      .word LBB123 - LJTI1_2
753    // If the .set directive is supported, this is emitted as:
754    //      .set L4_5_set_123, LBB123 - LJTI1_2
755    //      .word L4_5_set_123
756
757    // If we have emitted set directives for the jump table entries, print
758    // them rather than the entries themselves.  If we're emitting PIC, then
759    // emit the table entries as differences between two text section labels.
760    if (MAI->hasSetDirective()) {
761      // If we used .set, reference the .set's symbol.
762      Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
763                                      OutContext);
764      break;
765    }
766    // Otherwise, use the difference as the jump table entry.
767    Value = MCSymbolRefExpr::Create(MBB->getSymbol(OutContext), OutContext);
768    const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
769    Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
770    break;
771  }
772  }
773
774  assert(Value && "Unknown entry kind!");
775
776  unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
777  OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
778}
779
780
781/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
782/// special global used by LLVM.  If so, emit it and return true, otherwise
783/// do nothing and return false.
784bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
785  if (GV->getName() == "llvm.used") {
786    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
787      EmitLLVMUsedList(GV->getInitializer());
788    return true;
789  }
790
791  // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
792  if (GV->getSection() == "llvm.metadata" ||
793      GV->hasAvailableExternallyLinkage())
794    return true;
795
796  if (!GV->hasAppendingLinkage()) return false;
797
798  assert(GV->hasInitializer() && "Not a special LLVM global!");
799
800  const TargetData *TD = TM.getTargetData();
801  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
802  if (GV->getName() == "llvm.global_ctors") {
803    OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
804    EmitAlignment(Align, 0);
805    EmitXXStructorList(GV->getInitializer());
806
807    if (TM.getRelocationModel() == Reloc::Static &&
808        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
809      StringRef Sym(".constructors_used");
810      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
811                                      MCSA_Reference);
812    }
813    return true;
814  }
815
816  if (GV->getName() == "llvm.global_dtors") {
817    OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
818    EmitAlignment(Align, 0);
819    EmitXXStructorList(GV->getInitializer());
820
821    if (TM.getRelocationModel() == Reloc::Static &&
822        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
823      StringRef Sym(".destructors_used");
824      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
825                                      MCSA_Reference);
826    }
827    return true;
828  }
829
830  return false;
831}
832
833/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
834/// global in the specified llvm.used list for which emitUsedDirectiveFor
835/// is true, as being used with this directive.
836void AsmPrinter::EmitLLVMUsedList(Constant *List) {
837  // Should be an array of 'i8*'.
838  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
839  if (InitList == 0) return;
840
841  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
842    const GlobalValue *GV =
843      dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
844    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
845      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(GV),
846                                      MCSA_NoDeadStrip);
847  }
848}
849
850/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the
851/// function pointers, ignoring the init priority.
852void AsmPrinter::EmitXXStructorList(Constant *List) {
853  // Should be an array of '{ int, void ()* }' structs.  The first value is the
854  // init priority, which we ignore.
855  if (!isa<ConstantArray>(List)) return;
856  ConstantArray *InitList = cast<ConstantArray>(List);
857  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
858    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
859      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
860
861      if (CS->getOperand(1)->isNullValue())
862        return;  // Found a null terminator, exit printing.
863      // Emit the function pointer.
864      EmitGlobalConstant(CS->getOperand(1));
865    }
866}
867
868//===--------------------------------------------------------------------===//
869// Emission and print routines
870//
871
872/// EmitInt8 - Emit a byte directive and value.
873///
874void AsmPrinter::EmitInt8(int Value) const {
875  OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
876}
877
878/// EmitInt16 - Emit a short directive and value.
879///
880void AsmPrinter::EmitInt16(int Value) const {
881  OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
882}
883
884/// EmitInt32 - Emit a long directive and value.
885///
886void AsmPrinter::EmitInt32(int Value) const {
887  OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
888}
889
890/// EmitInt64 - Emit a long long directive and value.
891///
892void AsmPrinter::EmitInt64(uint64_t Value) const {
893  OutStreamer.EmitIntValue(Value, 8, 0/*addrspace*/);
894}
895
896//===----------------------------------------------------------------------===//
897
898// EmitAlignment - Emit an alignment directive to the specified power of
899// two boundary.  For example, if you pass in 3 here, you will get an 8
900// byte alignment.  If a global value is specified, and if that global has
901// an explicit alignment requested, it will unconditionally override the
902// alignment request.  However, if ForcedAlignBits is specified, this value
903// has final say: the ultimate alignment will be the max of ForcedAlignBits
904// and the alignment computed with NumBits and the global.
905//
906// The algorithm is:
907//     Align = NumBits;
908//     if (GV && GV->hasalignment) Align = GV->getalignment();
909//     Align = std::max(Align, ForcedAlignBits);
910//
911void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
912                               unsigned ForcedAlignBits,
913                               bool UseFillExpr) const {
914  if (GV && GV->getAlignment())
915    NumBits = Log2_32(GV->getAlignment());
916  NumBits = std::max(NumBits, ForcedAlignBits);
917
918  if (NumBits == 0) return;   // No need to emit alignment.
919
920  if (getCurrentSection()->getKind().isText())
921    OutStreamer.EmitCodeAlignment(1 << NumBits);
922  else
923    OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
924}
925
926/// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
927///
928static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
929  MCContext &Ctx = AP.OutContext;
930
931  if (CV->isNullValue() || isa<UndefValue>(CV))
932    return MCConstantExpr::Create(0, Ctx);
933
934  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
935    return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
936
937  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
938    return MCSymbolRefExpr::Create(AP.GetGlobalValueSymbol(GV), Ctx);
939  if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
940    return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
941
942  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
943  if (CE == 0) {
944    llvm_unreachable("Unknown constant value to lower!");
945    return MCConstantExpr::Create(0, Ctx);
946  }
947
948  switch (CE->getOpcode()) {
949  default:
950    // If the code isn't optimized, there may be outstanding folding
951    // opportunities. Attempt to fold the expression using TargetData as a
952    // last resort before giving up.
953    if (Constant *C =
954          ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
955      if (C != CE)
956        return LowerConstant(C, AP);
957#ifndef NDEBUG
958    CE->dump();
959#endif
960    llvm_unreachable("FIXME: Don't support this constant expr");
961  case Instruction::GetElementPtr: {
962    const TargetData &TD = *AP.TM.getTargetData();
963    // Generate a symbolic expression for the byte address
964    const Constant *PtrVal = CE->getOperand(0);
965    SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
966    int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
967                                         IdxVec.size());
968
969    const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
970    if (Offset == 0)
971      return Base;
972
973    // Truncate/sext the offset to the pointer size.
974    if (TD.getPointerSizeInBits() != 64) {
975      int SExtAmount = 64-TD.getPointerSizeInBits();
976      Offset = (Offset << SExtAmount) >> SExtAmount;
977    }
978
979    return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
980                                   Ctx);
981  }
982
983  case Instruction::Trunc:
984    // We emit the value and depend on the assembler to truncate the generated
985    // expression properly.  This is important for differences between
986    // blockaddress labels.  Since the two labels are in the same function, it
987    // is reasonable to treat their delta as a 32-bit value.
988    // FALL THROUGH.
989  case Instruction::BitCast:
990    return LowerConstant(CE->getOperand(0), AP);
991
992  case Instruction::IntToPtr: {
993    const TargetData &TD = *AP.TM.getTargetData();
994    // Handle casts to pointers by changing them into casts to the appropriate
995    // integer type.  This promotes constant folding and simplifies this code.
996    Constant *Op = CE->getOperand(0);
997    Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
998                                      false/*ZExt*/);
999    return LowerConstant(Op, AP);
1000  }
1001
1002  case Instruction::PtrToInt: {
1003    const TargetData &TD = *AP.TM.getTargetData();
1004    // Support only foldable casts to/from pointers that can be eliminated by
1005    // changing the pointer to the appropriately sized integer type.
1006    Constant *Op = CE->getOperand(0);
1007    const Type *Ty = CE->getType();
1008
1009    const MCExpr *OpExpr = LowerConstant(Op, AP);
1010
1011    // We can emit the pointer value into this slot if the slot is an
1012    // integer slot equal to the size of the pointer.
1013    if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1014      return OpExpr;
1015
1016    // Otherwise the pointer is smaller than the resultant integer, mask off
1017    // the high bits so we are sure to get a proper truncation if the input is
1018    // a constant expr.
1019    unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1020    const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1021    return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1022  }
1023
1024  // The MC library also has a right-shift operator, but it isn't consistently
1025  // signed or unsigned between different targets.
1026  case Instruction::Add:
1027  case Instruction::Sub:
1028  case Instruction::Mul:
1029  case Instruction::SDiv:
1030  case Instruction::SRem:
1031  case Instruction::Shl:
1032  case Instruction::And:
1033  case Instruction::Or:
1034  case Instruction::Xor: {
1035    const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1036    const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1037    switch (CE->getOpcode()) {
1038    default: llvm_unreachable("Unknown binary operator constant cast expr");
1039    case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1040    case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1041    case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1042    case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1043    case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1044    case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1045    case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1046    case Instruction::Or:  return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1047    case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1048    }
1049  }
1050  }
1051}
1052
1053static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1054                                    AsmPrinter &AP) {
1055  if (AddrSpace != 0 || !CA->isString()) {
1056    // Not a string.  Print the values in successive locations
1057    for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1058      AP.EmitGlobalConstant(CA->getOperand(i), AddrSpace);
1059    return;
1060  }
1061
1062  // Otherwise, it can be emitted as .ascii.
1063  SmallVector<char, 128> TmpVec;
1064  TmpVec.reserve(CA->getNumOperands());
1065  for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1066    TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1067
1068  AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1069}
1070
1071static void EmitGlobalConstantVector(const ConstantVector *CV,
1072                                     unsigned AddrSpace, AsmPrinter &AP) {
1073  for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1074    AP.EmitGlobalConstant(CV->getOperand(i), AddrSpace);
1075}
1076
1077static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1078                                     unsigned AddrSpace, AsmPrinter &AP) {
1079  // Print the fields in successive locations. Pad to align if needed!
1080  const TargetData *TD = AP.TM.getTargetData();
1081  unsigned Size = TD->getTypeAllocSize(CS->getType());
1082  const StructLayout *Layout = TD->getStructLayout(CS->getType());
1083  uint64_t SizeSoFar = 0;
1084  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1085    const Constant *Field = CS->getOperand(i);
1086
1087    // Check if padding is needed and insert one or more 0s.
1088    uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1089    uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1090                        - Layout->getElementOffset(i)) - FieldSize;
1091    SizeSoFar += FieldSize + PadSize;
1092
1093    // Now print the actual field value.
1094    AP.EmitGlobalConstant(Field, AddrSpace);
1095
1096    // Insert padding - this may include padding to increase the size of the
1097    // current field up to the ABI size (if the struct is not packed) as well
1098    // as padding to ensure that the next field starts at the right offset.
1099    AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1100  }
1101  assert(SizeSoFar == Layout->getSizeInBytes() &&
1102         "Layout of constant struct may be incorrect!");
1103}
1104
1105static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1106                                 AsmPrinter &AP) {
1107  // FP Constants are printed as integer constants to avoid losing
1108  // precision.
1109  if (CFP->getType()->isDoubleTy()) {
1110    if (AP.VerboseAsm) {
1111      double Val = CFP->getValueAPF().convertToDouble();
1112      AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1113    }
1114
1115    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1116    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1117    return;
1118  }
1119
1120  if (CFP->getType()->isFloatTy()) {
1121    if (AP.VerboseAsm) {
1122      float Val = CFP->getValueAPF().convertToFloat();
1123      AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1124    }
1125    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1126    AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1127    return;
1128  }
1129
1130  if (CFP->getType()->isX86_FP80Ty()) {
1131    // all long double variants are printed as hex
1132    // api needed to prevent premature destruction
1133    APInt API = CFP->getValueAPF().bitcastToAPInt();
1134    const uint64_t *p = API.getRawData();
1135    if (AP.VerboseAsm) {
1136      // Convert to double so we can print the approximate val as a comment.
1137      APFloat DoubleVal = CFP->getValueAPF();
1138      bool ignored;
1139      DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1140                        &ignored);
1141      AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1142        << DoubleVal.convertToDouble() << '\n';
1143    }
1144
1145    if (AP.TM.getTargetData()->isBigEndian()) {
1146      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1147      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1148    } else {
1149      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1150      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1151    }
1152
1153    // Emit the tail padding for the long double.
1154    const TargetData &TD = *AP.TM.getTargetData();
1155    AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1156                             TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1157    return;
1158  }
1159
1160  assert(CFP->getType()->isPPC_FP128Ty() &&
1161         "Floating point constant type not handled");
1162  // All long double variants are printed as hex api needed to prevent
1163  // premature destruction.
1164  APInt API = CFP->getValueAPF().bitcastToAPInt();
1165  const uint64_t *p = API.getRawData();
1166  if (AP.TM.getTargetData()->isBigEndian()) {
1167    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1168    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1169  } else {
1170    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1171    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1172  }
1173}
1174
1175static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1176                                       unsigned AddrSpace, AsmPrinter &AP) {
1177  const TargetData *TD = AP.TM.getTargetData();
1178  unsigned BitWidth = CI->getBitWidth();
1179  assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1180
1181  // We don't expect assemblers to support integer data directives
1182  // for more than 64 bits, so we emit the data in at most 64-bit
1183  // quantities at a time.
1184  const uint64_t *RawData = CI->getValue().getRawData();
1185  for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1186    uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1187    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1188  }
1189}
1190
1191/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1192void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1193  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1194    uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1195    if (Size == 0) Size = 1; // An empty "_foo:" followed by a section is undef.
1196    return OutStreamer.EmitZeros(Size, AddrSpace);
1197  }
1198
1199  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1200    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1201    switch (Size) {
1202    case 1:
1203    case 2:
1204    case 4:
1205    case 8:
1206      if (VerboseAsm)
1207        OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1208      OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1209      return;
1210    default:
1211      EmitGlobalConstantLargeInt(CI, AddrSpace, *this);
1212      return;
1213    }
1214  }
1215
1216  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1217    return EmitGlobalConstantArray(CVA, AddrSpace, *this);
1218
1219  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1220    return EmitGlobalConstantStruct(CVS, AddrSpace, *this);
1221
1222  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1223    return EmitGlobalConstantFP(CFP, AddrSpace, *this);
1224
1225  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1226    return EmitGlobalConstantVector(V, AddrSpace, *this);
1227
1228  if (isa<ConstantPointerNull>(CV)) {
1229    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1230    OutStreamer.EmitIntValue(0, Size, AddrSpace);
1231    return;
1232  }
1233
1234  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
1235  // thread the streamer with EmitValue.
1236  OutStreamer.EmitValue(LowerConstant(CV, *this),
1237                        TM.getTargetData()->getTypeAllocSize(CV->getType()),
1238                        AddrSpace);
1239}
1240
1241void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1242  // Target doesn't support this yet!
1243  llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1244}
1245
1246/// PrintSpecial - Print information related to the specified machine instr
1247/// that is independent of the operand, and may be independent of the instr
1248/// itself.  This can be useful for portably encoding the comment character
1249/// or other bits of target-specific knowledge into the asmstrings.  The
1250/// syntax used is ${:comment}.  Targets can override this to add support
1251/// for their own strange codes.
1252void AsmPrinter::PrintSpecial(const MachineInstr *MI, const char *Code) const {
1253  if (!strcmp(Code, "private")) {
1254    O << MAI->getPrivateGlobalPrefix();
1255  } else if (!strcmp(Code, "comment")) {
1256    if (VerboseAsm)
1257      O << MAI->getCommentString();
1258  } else if (!strcmp(Code, "uid")) {
1259    // Comparing the address of MI isn't sufficient, because machineinstrs may
1260    // be allocated to the same address across functions.
1261    const Function *ThisF = MI->getParent()->getParent()->getFunction();
1262
1263    // If this is a new LastFn instruction, bump the counter.
1264    if (LastMI != MI || LastFn != ThisF) {
1265      ++Counter;
1266      LastMI = MI;
1267      LastFn = ThisF;
1268    }
1269    O << Counter;
1270  } else {
1271    std::string msg;
1272    raw_string_ostream Msg(msg);
1273    Msg << "Unknown special formatter '" << Code
1274         << "' for machine instr: " << *MI;
1275    llvm_report_error(Msg.str());
1276  }
1277}
1278
1279/// processDebugLoc - Processes the debug information of each machine
1280/// instruction's DebugLoc.
1281void AsmPrinter::processDebugLoc(const MachineInstr *MI,
1282                                 bool BeforePrintingInsn) {
1283  if (!MAI || !DW || !MAI->doesSupportDebugInformation()
1284      || !DW->ShouldEmitDwarfDebug())
1285    return;
1286  DebugLoc DL = MI->getDebugLoc();
1287  if (DL.isUnknown())
1288    return;
1289  DILocation CurDLT = MF->getDILocation(DL);
1290  if (CurDLT.getScope().isNull())
1291    return;
1292
1293  if (!BeforePrintingInsn) {
1294    // After printing instruction
1295    DW->EndScope(MI);
1296  } else if (CurDLT.getNode() != PrevDLT) {
1297    unsigned L = DW->RecordSourceLine(CurDLT.getLineNumber(),
1298                                      CurDLT.getColumnNumber(),
1299                                      CurDLT.getScope().getNode());
1300    printLabel(L);
1301    O << '\n';
1302    DW->BeginScope(MI, L);
1303    PrevDLT = CurDLT.getNode();
1304  }
1305}
1306
1307
1308/// printInlineAsm - This method formats and prints the specified machine
1309/// instruction that is an inline asm.
1310void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
1311  unsigned NumOperands = MI->getNumOperands();
1312
1313  // Count the number of register definitions.
1314  unsigned NumDefs = 0;
1315  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
1316       ++NumDefs)
1317    assert(NumDefs != NumOperands-1 && "No asm string?");
1318
1319  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
1320
1321  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
1322  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
1323
1324  O << '\t';
1325
1326  // If this asmstr is empty, just print the #APP/#NOAPP markers.
1327  // These are useful to see where empty asm's wound up.
1328  if (AsmStr[0] == 0) {
1329    O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1330    O << MAI->getCommentString() << MAI->getInlineAsmEnd() << '\n';
1331    return;
1332  }
1333
1334  O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1335
1336  // The variant of the current asmprinter.
1337  int AsmPrinterVariant = MAI->getAssemblerDialect();
1338
1339  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
1340  const char *LastEmitted = AsmStr; // One past the last character emitted.
1341
1342  while (*LastEmitted) {
1343    switch (*LastEmitted) {
1344    default: {
1345      // Not a special case, emit the string section literally.
1346      const char *LiteralEnd = LastEmitted+1;
1347      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
1348             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
1349        ++LiteralEnd;
1350      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1351        O.write(LastEmitted, LiteralEnd-LastEmitted);
1352      LastEmitted = LiteralEnd;
1353      break;
1354    }
1355    case '\n':
1356      ++LastEmitted;   // Consume newline character.
1357      O << '\n';       // Indent code with newline.
1358      break;
1359    case '$': {
1360      ++LastEmitted;   // Consume '$' character.
1361      bool Done = true;
1362
1363      // Handle escapes.
1364      switch (*LastEmitted) {
1365      default: Done = false; break;
1366      case '$':     // $$ -> $
1367        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1368          O << '$';
1369        ++LastEmitted;  // Consume second '$' character.
1370        break;
1371      case '(':             // $( -> same as GCC's { character.
1372        ++LastEmitted;      // Consume '(' character.
1373        if (CurVariant != -1) {
1374          llvm_report_error("Nested variants found in inline asm string: '"
1375                            + std::string(AsmStr) + "'");
1376        }
1377        CurVariant = 0;     // We're in the first variant now.
1378        break;
1379      case '|':
1380        ++LastEmitted;  // consume '|' character.
1381        if (CurVariant == -1)
1382          O << '|';       // this is gcc's behavior for | outside a variant
1383        else
1384          ++CurVariant;   // We're in the next variant.
1385        break;
1386      case ')':         // $) -> same as GCC's } char.
1387        ++LastEmitted;  // consume ')' character.
1388        if (CurVariant == -1)
1389          O << '}';     // this is gcc's behavior for } outside a variant
1390        else
1391          CurVariant = -1;
1392        break;
1393      }
1394      if (Done) break;
1395
1396      bool HasCurlyBraces = false;
1397      if (*LastEmitted == '{') {     // ${variable}
1398        ++LastEmitted;               // Consume '{' character.
1399        HasCurlyBraces = true;
1400      }
1401
1402      // If we have ${:foo}, then this is not a real operand reference, it is a
1403      // "magic" string reference, just like in .td files.  Arrange to call
1404      // PrintSpecial.
1405      if (HasCurlyBraces && *LastEmitted == ':') {
1406        ++LastEmitted;
1407        const char *StrStart = LastEmitted;
1408        const char *StrEnd = strchr(StrStart, '}');
1409        if (StrEnd == 0) {
1410          llvm_report_error("Unterminated ${:foo} operand in inline asm string: '"
1411                            + std::string(AsmStr) + "'");
1412        }
1413
1414        std::string Val(StrStart, StrEnd);
1415        PrintSpecial(MI, Val.c_str());
1416        LastEmitted = StrEnd+1;
1417        break;
1418      }
1419
1420      const char *IDStart = LastEmitted;
1421      char *IDEnd;
1422      errno = 0;
1423      long Val = strtol(IDStart, &IDEnd, 10); // We only accept numbers for IDs.
1424      if (!isdigit(*IDStart) || (Val == 0 && errno == EINVAL)) {
1425        llvm_report_error("Bad $ operand number in inline asm string: '"
1426                          + std::string(AsmStr) + "'");
1427      }
1428      LastEmitted = IDEnd;
1429
1430      char Modifier[2] = { 0, 0 };
1431
1432      if (HasCurlyBraces) {
1433        // If we have curly braces, check for a modifier character.  This
1434        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
1435        if (*LastEmitted == ':') {
1436          ++LastEmitted;    // Consume ':' character.
1437          if (*LastEmitted == 0) {
1438            llvm_report_error("Bad ${:} expression in inline asm string: '"
1439                              + std::string(AsmStr) + "'");
1440          }
1441
1442          Modifier[0] = *LastEmitted;
1443          ++LastEmitted;    // Consume modifier character.
1444        }
1445
1446        if (*LastEmitted != '}') {
1447          llvm_report_error("Bad ${} expression in inline asm string: '"
1448                            + std::string(AsmStr) + "'");
1449        }
1450        ++LastEmitted;    // Consume '}' character.
1451      }
1452
1453      if ((unsigned)Val >= NumOperands-1) {
1454        llvm_report_error("Invalid $ operand number in inline asm string: '"
1455                          + std::string(AsmStr) + "'");
1456      }
1457
1458      // Okay, we finally have a value number.  Ask the target to print this
1459      // operand!
1460      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
1461        unsigned OpNo = 1;
1462
1463        bool Error = false;
1464
1465        // Scan to find the machine operand number for the operand.
1466        for (; Val; --Val) {
1467          if (OpNo >= MI->getNumOperands()) break;
1468          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1469          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
1470        }
1471
1472        if (OpNo >= MI->getNumOperands()) {
1473          Error = true;
1474        } else {
1475          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1476          ++OpNo;  // Skip over the ID number.
1477
1478          if (Modifier[0] == 'l')  // labels are target independent
1479            O << *MI->getOperand(OpNo).getMBB()->getSymbol(OutContext);
1480          else {
1481            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
1482            if ((OpFlags & 7) == 4) {
1483              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
1484                                                Modifier[0] ? Modifier : 0);
1485            } else {
1486              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
1487                                          Modifier[0] ? Modifier : 0);
1488            }
1489          }
1490        }
1491        if (Error) {
1492          std::string msg;
1493          raw_string_ostream Msg(msg);
1494          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
1495          MI->print(Msg);
1496          llvm_report_error(Msg.str());
1497        }
1498      }
1499      break;
1500    }
1501    }
1502  }
1503  O << "\n\t" << MAI->getCommentString() << MAI->getInlineAsmEnd();
1504  OutStreamer.AddBlankLine();
1505}
1506
1507/// printImplicitDef - This method prints the specified machine instruction
1508/// that is an implicit def.
1509void AsmPrinter::printImplicitDef(const MachineInstr *MI) const {
1510  if (!VerboseAsm) return;
1511  O.PadToColumn(MAI->getCommentColumn());
1512  O << MAI->getCommentString() << " implicit-def: "
1513    << TRI->getName(MI->getOperand(0).getReg());
1514  OutStreamer.AddBlankLine();
1515}
1516
1517void AsmPrinter::printKill(const MachineInstr *MI) const {
1518  if (!VerboseAsm) return;
1519  O.PadToColumn(MAI->getCommentColumn());
1520  O << MAI->getCommentString() << " kill:";
1521  for (unsigned n = 0, e = MI->getNumOperands(); n != e; ++n) {
1522    const MachineOperand &op = MI->getOperand(n);
1523    assert(op.isReg() && "KILL instruction must have only register operands");
1524    O << ' ' << TRI->getName(op.getReg()) << (op.isDef() ? "<def>" : "<kill>");
1525  }
1526  OutStreamer.AddBlankLine();
1527}
1528
1529/// printLabel - This method prints a local label used by debug and
1530/// exception handling tables.
1531void AsmPrinter::printLabelInst(const MachineInstr *MI) const {
1532  printLabel(MI->getOperand(0).getImm());
1533  OutStreamer.AddBlankLine();
1534}
1535
1536void AsmPrinter::printLabel(unsigned Id) const {
1537  O << MAI->getPrivateGlobalPrefix() << "label" << Id << ':';
1538}
1539
1540/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
1541/// instruction, using the specified assembler variant.  Targets should
1542/// override this to format as appropriate.
1543bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
1544                                 unsigned AsmVariant, const char *ExtraCode) {
1545  // Target doesn't support this yet!
1546  return true;
1547}
1548
1549bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
1550                                       unsigned AsmVariant,
1551                                       const char *ExtraCode) {
1552  // Target doesn't support this yet!
1553  return true;
1554}
1555
1556MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1557  return GetBlockAddressSymbol(BA->getFunction(), BA->getBasicBlock());
1558}
1559
1560MCSymbol *AsmPrinter::GetBlockAddressSymbol(const Function *F,
1561                                            const BasicBlock *BB) const {
1562  assert(BB->hasName() &&
1563         "Address of anonymous basic block not supported yet!");
1564
1565  // This code must use the function name itself, and not the function number,
1566  // since it must be possible to generate the label name from within other
1567  // functions.
1568  SmallString<60> FnName;
1569  Mang->getNameWithPrefix(FnName, F, false);
1570
1571  // FIXME: THIS IS BROKEN IF THE LLVM BASIC BLOCK DOESN'T HAVE A NAME!
1572  SmallString<60> NameResult;
1573  Mang->getNameWithPrefix(NameResult,
1574                          StringRef("BA") + Twine((unsigned)FnName.size()) +
1575                          "_" + FnName.str() + "_" + BB->getName(),
1576                          Mangler::Private);
1577
1578  return OutContext.GetOrCreateSymbol(NameResult.str());
1579}
1580
1581/// GetCPISymbol - Return the symbol for the specified constant pool entry.
1582MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1583  SmallString<60> Name;
1584  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix() << "CPI"
1585    << getFunctionNumber() << '_' << CPID;
1586  return OutContext.GetOrCreateSymbol(Name.str());
1587}
1588
1589/// GetJTISymbol - Return the symbol for the specified jump table entry.
1590MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1591  return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1592}
1593
1594/// GetJTSetSymbol - Return the symbol for the specified jump table .set
1595/// FIXME: privatize to AsmPrinter.
1596MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1597  SmallString<60> Name;
1598  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix()
1599    << getFunctionNumber() << '_' << UID << "_set_" << MBBID;
1600  return OutContext.GetOrCreateSymbol(Name.str());
1601}
1602
1603/// GetGlobalValueSymbol - Return the MCSymbol for the specified global
1604/// value.
1605MCSymbol *AsmPrinter::GetGlobalValueSymbol(const GlobalValue *GV) const {
1606  SmallString<60> NameStr;
1607  Mang->getNameWithPrefix(NameStr, GV, false);
1608  return OutContext.GetOrCreateSymbol(NameStr.str());
1609}
1610
1611/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1612/// global value name as its base, with the specified suffix, and where the
1613/// symbol is forced to have private linkage if ForcePrivate is true.
1614MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1615                                                   StringRef Suffix,
1616                                                   bool ForcePrivate) const {
1617  SmallString<60> NameStr;
1618  Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1619  NameStr.append(Suffix.begin(), Suffix.end());
1620  return OutContext.GetOrCreateSymbol(NameStr.str());
1621}
1622
1623/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1624/// ExternalSymbol.
1625MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1626  SmallString<60> NameStr;
1627  Mang->getNameWithPrefix(NameStr, Sym);
1628  return OutContext.GetOrCreateSymbol(NameStr.str());
1629}
1630
1631
1632
1633/// PrintParentLoopComment - Print comments about parent loops of this one.
1634static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1635                                   unsigned FunctionNumber) {
1636  if (Loop == 0) return;
1637  PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1638  OS.indent(Loop->getLoopDepth()*2)
1639    << "Parent Loop BB" << FunctionNumber << "_"
1640    << Loop->getHeader()->getNumber()
1641    << " Depth=" << Loop->getLoopDepth() << '\n';
1642}
1643
1644
1645/// PrintChildLoopComment - Print comments about child loops within
1646/// the loop for this basic block, with nesting.
1647static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1648                                  unsigned FunctionNumber) {
1649  // Add child loop information
1650  for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1651    OS.indent((*CL)->getLoopDepth()*2)
1652      << "Child Loop BB" << FunctionNumber << "_"
1653      << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1654      << '\n';
1655    PrintChildLoopComment(OS, *CL, FunctionNumber);
1656  }
1657}
1658
1659/// PrintBasicBlockLoopComments - Pretty-print comments for basic blocks.
1660static void PrintBasicBlockLoopComments(const MachineBasicBlock &MBB,
1661                                        const MachineLoopInfo *LI,
1662                                        const AsmPrinter &AP) {
1663  // Add loop depth information
1664  const MachineLoop *Loop = LI->getLoopFor(&MBB);
1665  if (Loop == 0) return;
1666
1667  MachineBasicBlock *Header = Loop->getHeader();
1668  assert(Header && "No header for loop");
1669
1670  // If this block is not a loop header, just print out what is the loop header
1671  // and return.
1672  if (Header != &MBB) {
1673    AP.OutStreamer.AddComment("  in Loop: Header=BB" +
1674                              Twine(AP.getFunctionNumber())+"_" +
1675                              Twine(Loop->getHeader()->getNumber())+
1676                              " Depth="+Twine(Loop->getLoopDepth()));
1677    return;
1678  }
1679
1680  // Otherwise, it is a loop header.  Print out information about child and
1681  // parent loops.
1682  raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1683
1684  PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1685
1686  OS << "=>";
1687  OS.indent(Loop->getLoopDepth()*2-2);
1688
1689  OS << "This ";
1690  if (Loop->empty())
1691    OS << "Inner ";
1692  OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1693
1694  PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1695}
1696
1697
1698/// EmitBasicBlockStart - This method prints the label for the specified
1699/// MachineBasicBlock, an alignment (if present) and a comment describing
1700/// it if appropriate.
1701void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1702  // Emit an alignment directive for this block, if needed.
1703  if (unsigned Align = MBB->getAlignment())
1704    EmitAlignment(Log2_32(Align));
1705
1706  // If the block has its address taken, emit a special label to satisfy
1707  // references to the block. This is done so that we don't need to
1708  // remember the number of this label, and so that we can make
1709  // forward references to labels without knowing what their numbers
1710  // will be.
1711  if (MBB->hasAddressTaken()) {
1712    const BasicBlock *BB = MBB->getBasicBlock();
1713    if (VerboseAsm)
1714      OutStreamer.AddComment("Address Taken");
1715    OutStreamer.EmitLabel(GetBlockAddressSymbol(BB->getParent(), BB));
1716  }
1717
1718  // Print the main label for the block.
1719  if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1720    if (VerboseAsm) {
1721      // NOTE: Want this comment at start of line.
1722      O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
1723      if (const BasicBlock *BB = MBB->getBasicBlock())
1724        if (BB->hasName())
1725          OutStreamer.AddComment("%" + BB->getName());
1726
1727      PrintBasicBlockLoopComments(*MBB, LI, *this);
1728      OutStreamer.AddBlankLine();
1729    }
1730  } else {
1731    if (VerboseAsm) {
1732      if (const BasicBlock *BB = MBB->getBasicBlock())
1733        if (BB->hasName())
1734          OutStreamer.AddComment("%" + BB->getName());
1735      PrintBasicBlockLoopComments(*MBB, LI, *this);
1736    }
1737
1738    OutStreamer.EmitLabel(MBB->getSymbol(OutContext));
1739  }
1740}
1741
1742void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1743  MCSymbolAttr Attr = MCSA_Invalid;
1744
1745  switch (Visibility) {
1746  default: break;
1747  case GlobalValue::HiddenVisibility:
1748    Attr = MAI->getHiddenVisibilityAttr();
1749    break;
1750  case GlobalValue::ProtectedVisibility:
1751    Attr = MAI->getProtectedVisibilityAttr();
1752    break;
1753  }
1754
1755  if (Attr != MCSA_Invalid)
1756    OutStreamer.EmitSymbolAttribute(Sym, Attr);
1757}
1758
1759void AsmPrinter::printOffset(int64_t Offset) const {
1760  if (Offset > 0)
1761    O << '+' << Offset;
1762  else if (Offset < 0)
1763    O << Offset;
1764}
1765
1766/// isBlockOnlyReachableByFallthough - Return true if the basic block has
1767/// exactly one predecessor and the control transfer mechanism between
1768/// the predecessor and this block is a fall-through.
1769bool AsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB)
1770    const {
1771  // If this is a landing pad, it isn't a fall through.  If it has no preds,
1772  // then nothing falls through to it.
1773  if (MBB->isLandingPad() || MBB->pred_empty())
1774    return false;
1775
1776  // If there isn't exactly one predecessor, it can't be a fall through.
1777  MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1778  ++PI2;
1779  if (PI2 != MBB->pred_end())
1780    return false;
1781
1782  // The predecessor has to be immediately before this block.
1783  const MachineBasicBlock *Pred = *PI;
1784
1785  if (!Pred->isLayoutSuccessor(MBB))
1786    return false;
1787
1788  // If the block is completely empty, then it definitely does fall through.
1789  if (Pred->empty())
1790    return true;
1791
1792  // Otherwise, check the last instruction.
1793  const MachineInstr &LastInst = Pred->back();
1794  return !LastInst.getDesc().isBarrier();
1795}
1796
1797
1798
1799GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1800  if (!S->usesMetadata())
1801    return 0;
1802
1803  gcp_iterator GCPI = GCMetadataPrinters.find(S);
1804  if (GCPI != GCMetadataPrinters.end())
1805    return GCPI->second;
1806
1807  const char *Name = S->getName().c_str();
1808
1809  for (GCMetadataPrinterRegistry::iterator
1810         I = GCMetadataPrinterRegistry::begin(),
1811         E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1812    if (strcmp(Name, I->getName()) == 0) {
1813      GCMetadataPrinter *GMP = I->instantiate();
1814      GMP->S = S;
1815      GCMetadataPrinters.insert(std::make_pair(S, GMP));
1816      return GMP;
1817    }
1818
1819  llvm_report_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
1820  return 0;
1821}
1822
1823