AsmPrinter.cpp revision 15b64f335b2d8566d58a5e791c12c0ca0a17fe7a 
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;
58
59AsmPrinter::AsmPrinter(formatted_raw_ostream &o, TargetMachine &tm,
60                       MCStreamer &Streamer)
61  : MachineFunctionPass(&ID), O(o),
62    TM(tm), MAI(tm.getMCAsmInfo()), TRI(tm.getRegisterInfo()),
63    OutContext(Streamer.getContext()),
64    OutStreamer(Streamer),
65    LastMI(0), LastFn(0), Counter(~0U), SetCounter(0), PrevDLT(NULL) {
66  DW = 0; MMI = 0;
67  VerboseAsm = Streamer.isVerboseAsm();
68}
69
70AsmPrinter::~AsmPrinter() {
71  for (gcp_iterator I = GCMetadataPrinters.begin(),
72                    E = GCMetadataPrinters.end(); I != E; ++I)
73    delete I->second;
74
75  delete &OutStreamer;
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<MachineModuleInfo>();
98  AU.addRequired<GCModuleInfo>();
99  if (VerboseAsm)
100    AU.addRequired<MachineLoopInfo>();
101}
102
103bool AsmPrinter::doInitialization(Module &M) {
104  MMI = getAnalysisIfAvailable<MachineModuleInfo>();
105  MMI->AnalyzeModule(M);
106
107  // Initialize TargetLoweringObjectFile.
108  const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
109    .Initialize(OutContext, TM);
110
111  Mang = new Mangler(OutContext, *TM.getTargetData());
112
113  // Allow the target to emit any magic that it wants at the start of the file.
114  EmitStartOfAsmFile(M);
115
116  // Very minimal debug info. It is ignored if we emit actual debug info. If we
117  // don't, this at least helps the user find where a global came from.
118  if (MAI->hasSingleParameterDotFile()) {
119    // .file "foo.c"
120    OutStreamer.EmitFileDirective(M.getModuleIdentifier());
121  }
122
123  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
124  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
125  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
126    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
127      MP->beginAssembly(O, *this, *MAI);
128
129  if (!M.getModuleInlineAsm().empty())
130    O << MAI->getCommentString() << " Start of file scope inline assembly\n"
131      << M.getModuleInlineAsm()
132      << '\n' << MAI->getCommentString()
133      << " End of file scope inline assembly\n";
134
135  DW = getAnalysisIfAvailable<DwarfWriter>();
136  if (DW)
137    DW->BeginModule(&M, MMI, O, this, MAI);
138
139  return false;
140}
141
142void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
143  switch ((GlobalValue::LinkageTypes)Linkage) {
144  case GlobalValue::CommonLinkage:
145  case GlobalValue::LinkOnceAnyLinkage:
146  case GlobalValue::LinkOnceODRLinkage:
147  case GlobalValue::WeakAnyLinkage:
148  case GlobalValue::WeakODRLinkage:
149  case GlobalValue::LinkerPrivateLinkage:
150    if (MAI->getWeakDefDirective() != 0) {
151      // .globl _foo
152      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
153      // .weak_definition _foo
154      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
155    } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) {
156      // .globl _foo
157      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
158      // FIXME: linkonce should be a section attribute, handled by COFF Section
159      // assignment.
160      // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce
161      // .linkonce discard
162      // FIXME: It would be nice to use .linkonce samesize for non-common
163      // globals.
164      O << LinkOnce;
165    } else {
166      // .weak _foo
167      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
168    }
169    break;
170  case GlobalValue::DLLExportLinkage:
171  case GlobalValue::AppendingLinkage:
172    // FIXME: appending linkage variables should go into a section of
173    // their name or something.  For now, just emit them as external.
174  case GlobalValue::ExternalLinkage:
175    // If external or appending, declare as a global symbol.
176    // .globl _foo
177    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
178    break;
179  case GlobalValue::PrivateLinkage:
180  case GlobalValue::InternalLinkage:
181    break;
182  default:
183    llvm_unreachable("Unknown linkage type!");
184  }
185}
186
187
188/// EmitGlobalVariable - Emit the specified global variable to the .s file.
189void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
190  if (!GV->hasInitializer())   // External globals require no code.
191    return;
192
193  // Check to see if this is a special global used by LLVM, if so, emit it.
194  if (EmitSpecialLLVMGlobal(GV))
195    return;
196
197  MCSymbol *GVSym = Mang->getSymbol(GV);
198  EmitVisibility(GVSym, GV->getVisibility());
199
200  if (MAI->hasDotTypeDotSizeDirective())
201    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
202
203  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
204
205  const TargetData *TD = TM.getTargetData();
206  unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType());
207  unsigned AlignLog = TD->getPreferredAlignmentLog(GV);
208
209  // Handle common and BSS local symbols (.lcomm).
210  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
211    if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
212
213    if (VerboseAsm) {
214      WriteAsOperand(OutStreamer.GetCommentOS(), GV,
215                     /*PrintType=*/false, GV->getParent());
216      OutStreamer.GetCommentOS() << '\n';
217    }
218
219    // Handle common symbols.
220    if (GVKind.isCommon()) {
221      // .comm _foo, 42, 4
222      OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
223      return;
224    }
225
226    // Handle local BSS symbols.
227    if (MAI->hasMachoZeroFillDirective()) {
228      const MCSection *TheSection =
229        getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
230      // .zerofill __DATA, __bss, _foo, 400, 5
231      OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
232      return;
233    }
234
235    if (MAI->hasLCOMMDirective()) {
236      // .lcomm _foo, 42
237      OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
238      return;
239    }
240
241    // .local _foo
242    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
243    // .comm _foo, 42, 4
244    OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
245    return;
246  }
247
248  const MCSection *TheSection =
249    getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
250
251  // Handle the zerofill directive on darwin, which is a special form of BSS
252  // emission.
253  if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
254    // .globl _foo
255    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
256    // .zerofill __DATA, __common, _foo, 400, 5
257    OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
258    return;
259  }
260
261  OutStreamer.SwitchSection(TheSection);
262
263  EmitLinkage(GV->getLinkage(), GVSym);
264  EmitAlignment(AlignLog, GV);
265
266  if (VerboseAsm) {
267    WriteAsOperand(OutStreamer.GetCommentOS(), GV,
268                   /*PrintType=*/false, GV->getParent());
269    OutStreamer.GetCommentOS() << '\n';
270  }
271  OutStreamer.EmitLabel(GVSym);
272
273  EmitGlobalConstant(GV->getInitializer());
274
275  if (MAI->hasDotTypeDotSizeDirective())
276    // .size foo, 42
277    OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
278
279  OutStreamer.AddBlankLine();
280}
281
282/// EmitFunctionHeader - This method emits the header for the current
283/// function.
284void AsmPrinter::EmitFunctionHeader() {
285  // Print out constants referenced by the function
286  EmitConstantPool();
287
288  // Print the 'header' of function.
289  const Function *F = MF->getFunction();
290
291  OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
292  EmitVisibility(CurrentFnSym, F->getVisibility());
293
294  EmitLinkage(F->getLinkage(), CurrentFnSym);
295  EmitAlignment(MF->getAlignment(), F);
296
297  if (MAI->hasDotTypeDotSizeDirective())
298    OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
299
300  if (VerboseAsm) {
301    WriteAsOperand(OutStreamer.GetCommentOS(), F,
302                   /*PrintType=*/false, F->getParent());
303    OutStreamer.GetCommentOS() << '\n';
304  }
305
306  // Emit the CurrentFnSym.  This is a virtual function to allow targets to
307  // do their wild and crazy things as required.
308  EmitFunctionEntryLabel();
309
310  // If the function had address-taken blocks that got deleted, then we have
311  // references to the dangling symbols.  Emit them at the start of the function
312  // so that we don't get references to undefined symbols.
313  std::vector<MCSymbol*> DeadBlockSyms;
314  MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
315  for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
316    OutStreamer.AddComment("Address taken block that was later removed");
317    OutStreamer.EmitLabel(DeadBlockSyms[i]);
318  }
319
320  // Add some workaround for linkonce linkage on Cygwin\MinGW.
321  if (MAI->getLinkOnceDirective() != 0 &&
322      (F->hasLinkOnceLinkage() || F->hasWeakLinkage()))
323    // FIXME: What is this?
324    O << "Lllvm$workaround$fake$stub$" << *CurrentFnSym << ":\n";
325
326  // Emit pre-function debug and/or EH information.
327  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
328    DW->BeginFunction(MF);
329}
330
331/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
332/// function.  This can be overridden by targets as required to do custom stuff.
333void AsmPrinter::EmitFunctionEntryLabel() {
334  OutStreamer.EmitLabel(CurrentFnSym);
335}
336
337
338/// EmitComments - Pretty-print comments for instructions.
339static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
340  const MachineFunction *MF = MI.getParent()->getParent();
341  const TargetMachine &TM = MF->getTarget();
342
343  if (!MI.getDebugLoc().isUnknown()) {
344    DILocation DLT = MF->getDILocation(MI.getDebugLoc());
345
346    // Print source line info.
347    DIScope Scope = DLT.getScope();
348    // Omit the directory, because it's likely to be long and uninteresting.
349    if (Scope.Verify())
350      CommentOS << Scope.getFilename();
351    else
352      CommentOS << "<unknown>";
353    CommentOS << ':' << DLT.getLineNumber();
354    if (DLT.getColumnNumber() != 0)
355      CommentOS << ':' << DLT.getColumnNumber();
356    CommentOS << '\n';
357  }
358
359  // Check for spills and reloads
360  int FI;
361
362  const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
363
364  // We assume a single instruction only has a spill or reload, not
365  // both.
366  const MachineMemOperand *MMO;
367  if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
368    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
369      MMO = *MI.memoperands_begin();
370      CommentOS << MMO->getSize() << "-byte Reload\n";
371    }
372  } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
373    if (FrameInfo->isSpillSlotObjectIndex(FI))
374      CommentOS << MMO->getSize() << "-byte Folded Reload\n";
375  } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
376    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
377      MMO = *MI.memoperands_begin();
378      CommentOS << MMO->getSize() << "-byte Spill\n";
379    }
380  } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
381    if (FrameInfo->isSpillSlotObjectIndex(FI))
382      CommentOS << MMO->getSize() << "-byte Folded Spill\n";
383  }
384
385  // Check for spill-induced copies
386  unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
387  if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
388                                     SrcSubIdx, DstSubIdx)) {
389    if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
390      CommentOS << " Reload Reuse\n";
391  }
392}
393
394
395
396/// EmitFunctionBody - This method emits the body and trailer for a
397/// function.
398void AsmPrinter::EmitFunctionBody() {
399  // Emit target-specific gunk before the function body.
400  EmitFunctionBodyStart();
401
402  // Print out code for the function.
403  bool HasAnyRealCode = false;
404  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
405       I != E; ++I) {
406    // Print a label for the basic block.
407    EmitBasicBlockStart(I);
408    for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
409         II != IE; ++II) {
410      // Print the assembly for the instruction.
411      if (!II->isLabel())
412        HasAnyRealCode = true;
413
414      ++EmittedInsts;
415
416      // FIXME: Clean up processDebugLoc.
417      processDebugLoc(II, true);
418
419      if (VerboseAsm)
420        EmitComments(*II, OutStreamer.GetCommentOS());
421
422      switch (II->getOpcode()) {
423      case TargetOpcode::DBG_LABEL:
424      case TargetOpcode::EH_LABEL:
425      case TargetOpcode::GC_LABEL:
426        printLabelInst(II);
427        break;
428      case TargetOpcode::INLINEASM:
429        printInlineAsm(II);
430        break;
431      case TargetOpcode::IMPLICIT_DEF:
432        printImplicitDef(II);
433        break;
434      case TargetOpcode::KILL:
435        printKill(II);
436        break;
437      default:
438        EmitInstruction(II);
439        break;
440      }
441
442      // FIXME: Clean up processDebugLoc.
443      processDebugLoc(II, false);
444    }
445  }
446
447  // If the function is empty and the object file uses .subsections_via_symbols,
448  // then we need to emit *something* to the function body to prevent the
449  // labels from collapsing together.  Just emit a 0 byte.
450  if (MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)
451    OutStreamer.EmitIntValue(0, 1, 0/*addrspace*/);
452
453  // Emit target-specific gunk after the function body.
454  EmitFunctionBodyEnd();
455
456  if (MAI->hasDotTypeDotSizeDirective())
457    O << "\t.size\t" << *CurrentFnSym << ", .-" << *CurrentFnSym << '\n';
458
459  // Emit post-function debug information.
460  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
461    DW->EndFunction(MF);
462
463  // Print out jump tables referenced by the function.
464  EmitJumpTableInfo();
465
466  OutStreamer.AddBlankLine();
467}
468
469
470bool AsmPrinter::doFinalization(Module &M) {
471  // Emit global variables.
472  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
473       I != E; ++I)
474    EmitGlobalVariable(I);
475
476  // Emit final debug information.
477  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
478    DW->EndModule();
479
480  // If the target wants to know about weak references, print them all.
481  if (MAI->getWeakRefDirective()) {
482    // FIXME: This is not lazy, it would be nice to only print weak references
483    // to stuff that is actually used.  Note that doing so would require targets
484    // to notice uses in operands (due to constant exprs etc).  This should
485    // happen with the MC stuff eventually.
486
487    // Print out module-level global variables here.
488    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
489         I != E; ++I) {
490      if (!I->hasExternalWeakLinkage()) continue;
491      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
492    }
493
494    for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
495      if (!I->hasExternalWeakLinkage()) continue;
496      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
497    }
498  }
499
500  if (MAI->hasSetDirective()) {
501    OutStreamer.AddBlankLine();
502    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
503         I != E; ++I) {
504      MCSymbol *Name = Mang->getSymbol(I);
505
506      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
507      MCSymbol *Target = Mang->getSymbol(GV);
508
509      if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
510        OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
511      else if (I->hasWeakLinkage())
512        OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
513      else
514        assert(I->hasLocalLinkage() && "Invalid alias linkage");
515
516      EmitVisibility(Name, I->getVisibility());
517
518      // Emit the directives as assignments aka .set:
519      OutStreamer.EmitAssignment(Name,
520                                 MCSymbolRefExpr::Create(Target, OutContext));
521    }
522  }
523
524  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
525  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
526  for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
527    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
528      MP->finishAssembly(O, *this, *MAI);
529
530  // If we don't have any trampolines, then we don't require stack memory
531  // to be executable. Some targets have a directive to declare this.
532  Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
533  if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
534    if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
535      OutStreamer.SwitchSection(S);
536
537  // Allow the target to emit any magic that it wants at the end of the file,
538  // after everything else has gone out.
539  EmitEndOfAsmFile(M);
540
541  delete Mang; Mang = 0;
542  DW = 0; MMI = 0;
543
544  OutStreamer.Finish();
545  return false;
546}
547
548void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
549  this->MF = &MF;
550  // Get the function symbol.
551  CurrentFnSym = Mang->getSymbol(MF.getFunction());
552
553  if (VerboseAsm)
554    LI = &getAnalysis<MachineLoopInfo>();
555}
556
557namespace {
558  // SectionCPs - Keep track the alignment, constpool entries per Section.
559  struct SectionCPs {
560    const MCSection *S;
561    unsigned Alignment;
562    SmallVector<unsigned, 4> CPEs;
563    SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
564  };
565}
566
567/// EmitConstantPool - Print to the current output stream assembly
568/// representations of the constants in the constant pool MCP. This is
569/// used to print out constants which have been "spilled to memory" by
570/// the code generator.
571///
572void AsmPrinter::EmitConstantPool() {
573  const MachineConstantPool *MCP = MF->getConstantPool();
574  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
575  if (CP.empty()) return;
576
577  // Calculate sections for constant pool entries. We collect entries to go into
578  // the same section together to reduce amount of section switch statements.
579  SmallVector<SectionCPs, 4> CPSections;
580  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
581    const MachineConstantPoolEntry &CPE = CP[i];
582    unsigned Align = CPE.getAlignment();
583
584    SectionKind Kind;
585    switch (CPE.getRelocationInfo()) {
586    default: llvm_unreachable("Unknown section kind");
587    case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
588    case 1:
589      Kind = SectionKind::getReadOnlyWithRelLocal();
590      break;
591    case 0:
592    switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
593    case 4:  Kind = SectionKind::getMergeableConst4(); break;
594    case 8:  Kind = SectionKind::getMergeableConst8(); break;
595    case 16: Kind = SectionKind::getMergeableConst16();break;
596    default: Kind = SectionKind::getMergeableConst(); break;
597    }
598    }
599
600    const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
601
602    // The number of sections are small, just do a linear search from the
603    // last section to the first.
604    bool Found = false;
605    unsigned SecIdx = CPSections.size();
606    while (SecIdx != 0) {
607      if (CPSections[--SecIdx].S == S) {
608        Found = true;
609        break;
610      }
611    }
612    if (!Found) {
613      SecIdx = CPSections.size();
614      CPSections.push_back(SectionCPs(S, Align));
615    }
616
617    if (Align > CPSections[SecIdx].Alignment)
618      CPSections[SecIdx].Alignment = Align;
619    CPSections[SecIdx].CPEs.push_back(i);
620  }
621
622  // Now print stuff into the calculated sections.
623  for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
624    OutStreamer.SwitchSection(CPSections[i].S);
625    EmitAlignment(Log2_32(CPSections[i].Alignment));
626
627    unsigned Offset = 0;
628    for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
629      unsigned CPI = CPSections[i].CPEs[j];
630      MachineConstantPoolEntry CPE = CP[CPI];
631
632      // Emit inter-object padding for alignment.
633      unsigned AlignMask = CPE.getAlignment() - 1;
634      unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
635      OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
636
637      const Type *Ty = CPE.getType();
638      Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
639
640      // Emit the label with a comment on it.
641      if (VerboseAsm) {
642        OutStreamer.GetCommentOS() << "constant pool ";
643        WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
644                          MF->getFunction()->getParent());
645        OutStreamer.GetCommentOS() << '\n';
646      }
647      OutStreamer.EmitLabel(GetCPISymbol(CPI));
648
649      if (CPE.isMachineConstantPoolEntry())
650        EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
651      else
652        EmitGlobalConstant(CPE.Val.ConstVal);
653    }
654  }
655}
656
657/// EmitJumpTableInfo - Print assembly representations of the jump tables used
658/// by the current function to the current output stream.
659///
660void AsmPrinter::EmitJumpTableInfo() {
661  const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
662  if (MJTI == 0) return;
663  if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
664  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
665  if (JT.empty()) return;
666
667  // Pick the directive to use to print the jump table entries, and switch to
668  // the appropriate section.
669  const Function *F = MF->getFunction();
670  bool JTInDiffSection = false;
671  if (// In PIC mode, we need to emit the jump table to the same section as the
672      // function body itself, otherwise the label differences won't make sense.
673      // FIXME: Need a better predicate for this: what about custom entries?
674      MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
675      // We should also do if the section name is NULL or function is declared
676      // in discardable section
677      // FIXME: this isn't the right predicate, should be based on the MCSection
678      // for the function.
679      F->isWeakForLinker()) {
680    OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
681  } else {
682    // Otherwise, drop it in the readonly section.
683    const MCSection *ReadOnlySection =
684      getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
685    OutStreamer.SwitchSection(ReadOnlySection);
686    JTInDiffSection = true;
687  }
688
689  EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
690
691  for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
692    const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
693
694    // If this jump table was deleted, ignore it.
695    if (JTBBs.empty()) continue;
696
697    // For the EK_LabelDifference32 entry, if the target supports .set, emit a
698    // .set directive for each unique entry.  This reduces the number of
699    // relocations the assembler will generate for the jump table.
700    if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
701        MAI->hasSetDirective()) {
702      SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
703      const TargetLowering *TLI = TM.getTargetLowering();
704      const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
705      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
706        const MachineBasicBlock *MBB = JTBBs[ii];
707        if (!EmittedSets.insert(MBB)) continue;
708
709        // .set LJTSet, LBB32-base
710        const MCExpr *LHS =
711          MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
712        OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
713                                MCBinaryExpr::CreateSub(LHS, Base, OutContext));
714      }
715    }
716
717    // On some targets (e.g. Darwin) we want to emit two consequtive labels
718    // before each jump table.  The first label is never referenced, but tells
719    // the assembler and linker the extents of the jump table object.  The
720    // second label is actually referenced by the code.
721    if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
722      // FIXME: This doesn't have to have any specific name, just any randomly
723      // named and numbered 'l' label would work.  Simplify GetJTISymbol.
724      OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
725
726    OutStreamer.EmitLabel(GetJTISymbol(JTI));
727
728    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
729      EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
730  }
731}
732
733/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
734/// current stream.
735void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
736                                    const MachineBasicBlock *MBB,
737                                    unsigned UID) const {
738  const MCExpr *Value = 0;
739  switch (MJTI->getEntryKind()) {
740  case MachineJumpTableInfo::EK_Inline:
741    llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
742  case MachineJumpTableInfo::EK_Custom32:
743    Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
744                                                              OutContext);
745    break;
746  case MachineJumpTableInfo::EK_BlockAddress:
747    // EK_BlockAddress - Each entry is a plain address of block, e.g.:
748    //     .word LBB123
749    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
750    break;
751  case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
752    // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
753    // with a relocation as gp-relative, e.g.:
754    //     .gprel32 LBB123
755    MCSymbol *MBBSym = MBB->getSymbol();
756    OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
757    return;
758  }
759
760  case MachineJumpTableInfo::EK_LabelDifference32: {
761    // EK_LabelDifference32 - Each entry is the address of the block minus
762    // the address of the jump table.  This is used for PIC jump tables where
763    // gprel32 is not supported.  e.g.:
764    //      .word LBB123 - LJTI1_2
765    // If the .set directive is supported, this is emitted as:
766    //      .set L4_5_set_123, LBB123 - LJTI1_2
767    //      .word L4_5_set_123
768
769    // If we have emitted set directives for the jump table entries, print
770    // them rather than the entries themselves.  If we're emitting PIC, then
771    // emit the table entries as differences between two text section labels.
772    if (MAI->hasSetDirective()) {
773      // If we used .set, reference the .set's symbol.
774      Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
775                                      OutContext);
776      break;
777    }
778    // Otherwise, use the difference as the jump table entry.
779    Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
780    const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
781    Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
782    break;
783  }
784  }
785
786  assert(Value && "Unknown entry kind!");
787
788  unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
789  OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
790}
791
792
793/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
794/// special global used by LLVM.  If so, emit it and return true, otherwise
795/// do nothing and return false.
796bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
797  if (GV->getName() == "llvm.used") {
798    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
799      EmitLLVMUsedList(GV->getInitializer());
800    return true;
801  }
802
803  // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
804  if (GV->getSection() == "llvm.metadata" ||
805      GV->hasAvailableExternallyLinkage())
806    return true;
807
808  if (!GV->hasAppendingLinkage()) return false;
809
810  assert(GV->hasInitializer() && "Not a special LLVM global!");
811
812  const TargetData *TD = TM.getTargetData();
813  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
814  if (GV->getName() == "llvm.global_ctors") {
815    OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
816    EmitAlignment(Align, 0);
817    EmitXXStructorList(GV->getInitializer());
818
819    if (TM.getRelocationModel() == Reloc::Static &&
820        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
821      StringRef Sym(".constructors_used");
822      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
823                                      MCSA_Reference);
824    }
825    return true;
826  }
827
828  if (GV->getName() == "llvm.global_dtors") {
829    OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
830    EmitAlignment(Align, 0);
831    EmitXXStructorList(GV->getInitializer());
832
833    if (TM.getRelocationModel() == Reloc::Static &&
834        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
835      StringRef Sym(".destructors_used");
836      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
837                                      MCSA_Reference);
838    }
839    return true;
840  }
841
842  return false;
843}
844
845/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
846/// global in the specified llvm.used list for which emitUsedDirectiveFor
847/// is true, as being used with this directive.
848void AsmPrinter::EmitLLVMUsedList(Constant *List) {
849  // Should be an array of 'i8*'.
850  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
851  if (InitList == 0) return;
852
853  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
854    const GlobalValue *GV =
855      dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
856    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
857      OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
858  }
859}
860
861/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the
862/// function pointers, ignoring the init priority.
863void AsmPrinter::EmitXXStructorList(Constant *List) {
864  // Should be an array of '{ int, void ()* }' structs.  The first value is the
865  // init priority, which we ignore.
866  if (!isa<ConstantArray>(List)) return;
867  ConstantArray *InitList = cast<ConstantArray>(List);
868  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
869    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
870      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
871
872      if (CS->getOperand(1)->isNullValue())
873        return;  // Found a null terminator, exit printing.
874      // Emit the function pointer.
875      EmitGlobalConstant(CS->getOperand(1));
876    }
877}
878
879//===--------------------------------------------------------------------===//
880// Emission and print routines
881//
882
883/// EmitInt8 - Emit a byte directive and value.
884///
885void AsmPrinter::EmitInt8(int Value) const {
886  OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
887}
888
889/// EmitInt16 - Emit a short directive and value.
890///
891void AsmPrinter::EmitInt16(int Value) const {
892  OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
893}
894
895/// EmitInt32 - Emit a long directive and value.
896///
897void AsmPrinter::EmitInt32(int Value) const {
898  OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
899}
900
901/// EmitInt64 - Emit a long long directive and value.
902///
903void AsmPrinter::EmitInt64(uint64_t Value) const {
904  OutStreamer.EmitIntValue(Value, 8, 0/*addrspace*/);
905}
906
907/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
908/// in bytes of the directive is specified by Size and Hi/Lo specify the
909/// labels.  This implicitly uses .set if it is available.
910void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
911                                     unsigned Size) const {
912  // Get the Hi-Lo expression.
913  const MCExpr *Diff =
914    MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
915                            MCSymbolRefExpr::Create(Lo, OutContext),
916                            OutContext);
917
918  if (!MAI->hasSetDirective()) {
919    OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
920    return;
921  }
922
923  // Otherwise, emit with .set (aka assignment).
924  MCSymbol *SetLabel =
925    OutContext.GetOrCreateTemporarySymbol(Twine(MAI->getPrivateGlobalPrefix()) +
926                                          "set" + Twine(SetCounter++));
927  OutStreamer.EmitAssignment(SetLabel, Diff);
928  OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
929}
930
931
932//===----------------------------------------------------------------------===//
933
934// EmitAlignment - Emit an alignment directive to the specified power of
935// two boundary.  For example, if you pass in 3 here, you will get an 8
936// byte alignment.  If a global value is specified, and if that global has
937// an explicit alignment requested, it will unconditionally override the
938// alignment request.  However, if ForcedAlignBits is specified, this value
939// has final say: the ultimate alignment will be the max of ForcedAlignBits
940// and the alignment computed with NumBits and the global.
941//
942// The algorithm is:
943//     Align = NumBits;
944//     if (GV && GV->hasalignment) Align = GV->getalignment();
945//     Align = std::max(Align, ForcedAlignBits);
946//
947void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
948                               unsigned ForcedAlignBits,
949                               bool UseFillExpr) const {
950  if (GV && GV->getAlignment())
951    NumBits = Log2_32(GV->getAlignment());
952  NumBits = std::max(NumBits, ForcedAlignBits);
953
954  if (NumBits == 0) return;   // No need to emit alignment.
955
956  if (getCurrentSection()->getKind().isText())
957    OutStreamer.EmitCodeAlignment(1 << NumBits);
958  else
959    OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
960}
961
962/// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
963///
964static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
965  MCContext &Ctx = AP.OutContext;
966
967  if (CV->isNullValue() || isa<UndefValue>(CV))
968    return MCConstantExpr::Create(0, Ctx);
969
970  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
971    return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
972
973  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
974    return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
975  if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
976    return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
977
978  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
979  if (CE == 0) {
980    llvm_unreachable("Unknown constant value to lower!");
981    return MCConstantExpr::Create(0, Ctx);
982  }
983
984  switch (CE->getOpcode()) {
985  default:
986    // If the code isn't optimized, there may be outstanding folding
987    // opportunities. Attempt to fold the expression using TargetData as a
988    // last resort before giving up.
989    if (Constant *C =
990          ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
991      if (C != CE)
992        return LowerConstant(C, AP);
993#ifndef NDEBUG
994    CE->dump();
995#endif
996    llvm_unreachable("FIXME: Don't support this constant expr");
997  case Instruction::GetElementPtr: {
998    const TargetData &TD = *AP.TM.getTargetData();
999    // Generate a symbolic expression for the byte address
1000    const Constant *PtrVal = CE->getOperand(0);
1001    SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
1002    int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
1003                                         IdxVec.size());
1004
1005    const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
1006    if (Offset == 0)
1007      return Base;
1008
1009    // Truncate/sext the offset to the pointer size.
1010    if (TD.getPointerSizeInBits() != 64) {
1011      int SExtAmount = 64-TD.getPointerSizeInBits();
1012      Offset = (Offset << SExtAmount) >> SExtAmount;
1013    }
1014
1015    return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1016                                   Ctx);
1017  }
1018
1019  case Instruction::Trunc:
1020    // We emit the value and depend on the assembler to truncate the generated
1021    // expression properly.  This is important for differences between
1022    // blockaddress labels.  Since the two labels are in the same function, it
1023    // is reasonable to treat their delta as a 32-bit value.
1024    // FALL THROUGH.
1025  case Instruction::BitCast:
1026    return LowerConstant(CE->getOperand(0), AP);
1027
1028  case Instruction::IntToPtr: {
1029    const TargetData &TD = *AP.TM.getTargetData();
1030    // Handle casts to pointers by changing them into casts to the appropriate
1031    // integer type.  This promotes constant folding and simplifies this code.
1032    Constant *Op = CE->getOperand(0);
1033    Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
1034                                      false/*ZExt*/);
1035    return LowerConstant(Op, AP);
1036  }
1037
1038  case Instruction::PtrToInt: {
1039    const TargetData &TD = *AP.TM.getTargetData();
1040    // Support only foldable casts to/from pointers that can be eliminated by
1041    // changing the pointer to the appropriately sized integer type.
1042    Constant *Op = CE->getOperand(0);
1043    const Type *Ty = CE->getType();
1044
1045    const MCExpr *OpExpr = LowerConstant(Op, AP);
1046
1047    // We can emit the pointer value into this slot if the slot is an
1048    // integer slot equal to the size of the pointer.
1049    if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
1050      return OpExpr;
1051
1052    // Otherwise the pointer is smaller than the resultant integer, mask off
1053    // the high bits so we are sure to get a proper truncation if the input is
1054    // a constant expr.
1055    unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
1056    const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1057    return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1058  }
1059
1060  // The MC library also has a right-shift operator, but it isn't consistently
1061  // signed or unsigned between different targets.
1062  case Instruction::Add:
1063  case Instruction::Sub:
1064  case Instruction::Mul:
1065  case Instruction::SDiv:
1066  case Instruction::SRem:
1067  case Instruction::Shl:
1068  case Instruction::And:
1069  case Instruction::Or:
1070  case Instruction::Xor: {
1071    const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
1072    const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
1073    switch (CE->getOpcode()) {
1074    default: llvm_unreachable("Unknown binary operator constant cast expr");
1075    case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1076    case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1077    case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1078    case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1079    case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1080    case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1081    case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1082    case Instruction::Or:  return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1083    case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1084    }
1085  }
1086  }
1087}
1088
1089static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
1090                                    AsmPrinter &AP) {
1091  if (AddrSpace != 0 || !CA->isString()) {
1092    // Not a string.  Print the values in successive locations
1093    for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1094      AP.EmitGlobalConstant(CA->getOperand(i), AddrSpace);
1095    return;
1096  }
1097
1098  // Otherwise, it can be emitted as .ascii.
1099  SmallVector<char, 128> TmpVec;
1100  TmpVec.reserve(CA->getNumOperands());
1101  for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1102    TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
1103
1104  AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
1105}
1106
1107static void EmitGlobalConstantVector(const ConstantVector *CV,
1108                                     unsigned AddrSpace, AsmPrinter &AP) {
1109  for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1110    AP.EmitGlobalConstant(CV->getOperand(i), AddrSpace);
1111}
1112
1113static void EmitGlobalConstantStruct(const ConstantStruct *CS,
1114                                     unsigned AddrSpace, AsmPrinter &AP) {
1115  // Print the fields in successive locations. Pad to align if needed!
1116  const TargetData *TD = AP.TM.getTargetData();
1117  unsigned Size = TD->getTypeAllocSize(CS->getType());
1118  const StructLayout *Layout = TD->getStructLayout(CS->getType());
1119  uint64_t SizeSoFar = 0;
1120  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1121    const Constant *Field = CS->getOperand(i);
1122
1123    // Check if padding is needed and insert one or more 0s.
1124    uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
1125    uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1126                        - Layout->getElementOffset(i)) - FieldSize;
1127    SizeSoFar += FieldSize + PadSize;
1128
1129    // Now print the actual field value.
1130    AP.EmitGlobalConstant(Field, AddrSpace);
1131
1132    // Insert padding - this may include padding to increase the size of the
1133    // current field up to the ABI size (if the struct is not packed) as well
1134    // as padding to ensure that the next field starts at the right offset.
1135    AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
1136  }
1137  assert(SizeSoFar == Layout->getSizeInBytes() &&
1138         "Layout of constant struct may be incorrect!");
1139}
1140
1141static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
1142                                 AsmPrinter &AP) {
1143  // FP Constants are printed as integer constants to avoid losing
1144  // precision.
1145  if (CFP->getType()->isDoubleTy()) {
1146    if (AP.VerboseAsm) {
1147      double Val = CFP->getValueAPF().convertToDouble();
1148      AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
1149    }
1150
1151    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1152    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1153    return;
1154  }
1155
1156  if (CFP->getType()->isFloatTy()) {
1157    if (AP.VerboseAsm) {
1158      float Val = CFP->getValueAPF().convertToFloat();
1159      AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
1160    }
1161    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
1162    AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
1163    return;
1164  }
1165
1166  if (CFP->getType()->isX86_FP80Ty()) {
1167    // all long double variants are printed as hex
1168    // api needed to prevent premature destruction
1169    APInt API = CFP->getValueAPF().bitcastToAPInt();
1170    const uint64_t *p = API.getRawData();
1171    if (AP.VerboseAsm) {
1172      // Convert to double so we can print the approximate val as a comment.
1173      APFloat DoubleVal = CFP->getValueAPF();
1174      bool ignored;
1175      DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
1176                        &ignored);
1177      AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
1178        << DoubleVal.convertToDouble() << '\n';
1179    }
1180
1181    if (AP.TM.getTargetData()->isBigEndian()) {
1182      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1183      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1184    } else {
1185      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1186      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
1187    }
1188
1189    // Emit the tail padding for the long double.
1190    const TargetData &TD = *AP.TM.getTargetData();
1191    AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
1192                             TD.getTypeStoreSize(CFP->getType()), AddrSpace);
1193    return;
1194  }
1195
1196  assert(CFP->getType()->isPPC_FP128Ty() &&
1197         "Floating point constant type not handled");
1198  // All long double variants are printed as hex api needed to prevent
1199  // premature destruction.
1200  APInt API = CFP->getValueAPF().bitcastToAPInt();
1201  const uint64_t *p = API.getRawData();
1202  if (AP.TM.getTargetData()->isBigEndian()) {
1203    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1204    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1205  } else {
1206    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
1207    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
1208  }
1209}
1210
1211static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
1212                                       unsigned AddrSpace, AsmPrinter &AP) {
1213  const TargetData *TD = AP.TM.getTargetData();
1214  unsigned BitWidth = CI->getBitWidth();
1215  assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
1216
1217  // We don't expect assemblers to support integer data directives
1218  // for more than 64 bits, so we emit the data in at most 64-bit
1219  // quantities at a time.
1220  const uint64_t *RawData = CI->getValue().getRawData();
1221  for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1222    uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1223    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
1224  }
1225}
1226
1227/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
1228void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
1229  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
1230    uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1231    if (Size == 0) Size = 1; // An empty "_foo:" followed by a section is undef.
1232    return OutStreamer.EmitZeros(Size, AddrSpace);
1233  }
1234
1235  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1236    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1237    switch (Size) {
1238    case 1:
1239    case 2:
1240    case 4:
1241    case 8:
1242      if (VerboseAsm)
1243        OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
1244      OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
1245      return;
1246    default:
1247      EmitGlobalConstantLargeInt(CI, AddrSpace, *this);
1248      return;
1249    }
1250  }
1251
1252  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
1253    return EmitGlobalConstantArray(CVA, AddrSpace, *this);
1254
1255  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
1256    return EmitGlobalConstantStruct(CVS, AddrSpace, *this);
1257
1258  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1259    return EmitGlobalConstantFP(CFP, AddrSpace, *this);
1260
1261  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1262    return EmitGlobalConstantVector(V, AddrSpace, *this);
1263
1264  if (isa<ConstantPointerNull>(CV)) {
1265    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1266    OutStreamer.EmitIntValue(0, Size, AddrSpace);
1267    return;
1268  }
1269
1270  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
1271  // thread the streamer with EmitValue.
1272  OutStreamer.EmitValue(LowerConstant(CV, *this),
1273                        TM.getTargetData()->getTypeAllocSize(CV->getType()),
1274                        AddrSpace);
1275}
1276
1277void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1278  // Target doesn't support this yet!
1279  llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1280}
1281
1282/// PrintSpecial - Print information related to the specified machine instr
1283/// that is independent of the operand, and may be independent of the instr
1284/// itself.  This can be useful for portably encoding the comment character
1285/// or other bits of target-specific knowledge into the asmstrings.  The
1286/// syntax used is ${:comment}.  Targets can override this to add support
1287/// for their own strange codes.
1288void AsmPrinter::PrintSpecial(const MachineInstr *MI, const char *Code) const {
1289  if (!strcmp(Code, "private")) {
1290    O << MAI->getPrivateGlobalPrefix();
1291  } else if (!strcmp(Code, "comment")) {
1292    if (VerboseAsm)
1293      O << MAI->getCommentString();
1294  } else if (!strcmp(Code, "uid")) {
1295    // Comparing the address of MI isn't sufficient, because machineinstrs may
1296    // be allocated to the same address across functions.
1297    const Function *ThisF = MI->getParent()->getParent()->getFunction();
1298
1299    // If this is a new LastFn instruction, bump the counter.
1300    if (LastMI != MI || LastFn != ThisF) {
1301      ++Counter;
1302      LastMI = MI;
1303      LastFn = ThisF;
1304    }
1305    O << Counter;
1306  } else {
1307    std::string msg;
1308    raw_string_ostream Msg(msg);
1309    Msg << "Unknown special formatter '" << Code
1310         << "' for machine instr: " << *MI;
1311    llvm_report_error(Msg.str());
1312  }
1313}
1314
1315/// processDebugLoc - Processes the debug information of each machine
1316/// instruction's DebugLoc.
1317void AsmPrinter::processDebugLoc(const MachineInstr *MI,
1318                                 bool BeforePrintingInsn) {
1319  if (!MAI || !DW || !MAI->doesSupportDebugInformation()
1320      || !DW->ShouldEmitDwarfDebug())
1321    return;
1322  if (MI->getOpcode() == TargetOpcode::DBG_VALUE)
1323    return;
1324  DebugLoc DL = MI->getDebugLoc();
1325  if (DL.isUnknown())
1326    return;
1327  DILocation CurDLT = MF->getDILocation(DL);
1328  if (!CurDLT.getScope().Verify())
1329    return;
1330
1331  if (!BeforePrintingInsn) {
1332    // After printing instruction
1333    DW->EndScope(MI);
1334  } else if (CurDLT.getNode() != PrevDLT) {
1335    MCSymbol *L = DW->RecordSourceLine(CurDLT.getLineNumber(),
1336                                       CurDLT.getColumnNumber(),
1337                                       CurDLT.getScope().getNode());
1338    DW->BeginScope(MI, L);
1339    PrevDLT = CurDLT.getNode();
1340  }
1341}
1342
1343
1344/// printInlineAsm - This method formats and prints the specified machine
1345/// instruction that is an inline asm.
1346void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
1347  unsigned NumOperands = MI->getNumOperands();
1348
1349  // Count the number of register definitions.
1350  unsigned NumDefs = 0;
1351  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
1352       ++NumDefs)
1353    assert(NumDefs != NumOperands-1 && "No asm string?");
1354
1355  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
1356
1357  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
1358  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
1359
1360  O << '\t';
1361
1362  // If this asmstr is empty, just print the #APP/#NOAPP markers.
1363  // These are useful to see where empty asm's wound up.
1364  if (AsmStr[0] == 0) {
1365    O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1366    O << MAI->getCommentString() << MAI->getInlineAsmEnd() << '\n';
1367    return;
1368  }
1369
1370  O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1371
1372  // The variant of the current asmprinter.
1373  int AsmPrinterVariant = MAI->getAssemblerDialect();
1374
1375  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
1376  const char *LastEmitted = AsmStr; // One past the last character emitted.
1377
1378  while (*LastEmitted) {
1379    switch (*LastEmitted) {
1380    default: {
1381      // Not a special case, emit the string section literally.
1382      const char *LiteralEnd = LastEmitted+1;
1383      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
1384             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
1385        ++LiteralEnd;
1386      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1387        O.write(LastEmitted, LiteralEnd-LastEmitted);
1388      LastEmitted = LiteralEnd;
1389      break;
1390    }
1391    case '\n':
1392      ++LastEmitted;   // Consume newline character.
1393      O << '\n';       // Indent code with newline.
1394      break;
1395    case '$': {
1396      ++LastEmitted;   // Consume '$' character.
1397      bool Done = true;
1398
1399      // Handle escapes.
1400      switch (*LastEmitted) {
1401      default: Done = false; break;
1402      case '$':     // $$ -> $
1403        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1404          O << '$';
1405        ++LastEmitted;  // Consume second '$' character.
1406        break;
1407      case '(':             // $( -> same as GCC's { character.
1408        ++LastEmitted;      // Consume '(' character.
1409        if (CurVariant != -1) {
1410          llvm_report_error("Nested variants found in inline asm string: '"
1411                            + std::string(AsmStr) + "'");
1412        }
1413        CurVariant = 0;     // We're in the first variant now.
1414        break;
1415      case '|':
1416        ++LastEmitted;  // consume '|' character.
1417        if (CurVariant == -1)
1418          O << '|';       // this is gcc's behavior for | outside a variant
1419        else
1420          ++CurVariant;   // We're in the next variant.
1421        break;
1422      case ')':         // $) -> same as GCC's } char.
1423        ++LastEmitted;  // consume ')' character.
1424        if (CurVariant == -1)
1425          O << '}';     // this is gcc's behavior for } outside a variant
1426        else
1427          CurVariant = -1;
1428        break;
1429      }
1430      if (Done) break;
1431
1432      bool HasCurlyBraces = false;
1433      if (*LastEmitted == '{') {     // ${variable}
1434        ++LastEmitted;               // Consume '{' character.
1435        HasCurlyBraces = true;
1436      }
1437
1438      // If we have ${:foo}, then this is not a real operand reference, it is a
1439      // "magic" string reference, just like in .td files.  Arrange to call
1440      // PrintSpecial.
1441      if (HasCurlyBraces && *LastEmitted == ':') {
1442        ++LastEmitted;
1443        const char *StrStart = LastEmitted;
1444        const char *StrEnd = strchr(StrStart, '}');
1445        if (StrEnd == 0) {
1446          llvm_report_error("Unterminated ${:foo} operand in inline asm string: '"
1447                            + std::string(AsmStr) + "'");
1448        }
1449
1450        std::string Val(StrStart, StrEnd);
1451        PrintSpecial(MI, Val.c_str());
1452        LastEmitted = StrEnd+1;
1453        break;
1454      }
1455
1456      const char *IDStart = LastEmitted;
1457      char *IDEnd;
1458      errno = 0;
1459      long Val = strtol(IDStart, &IDEnd, 10); // We only accept numbers for IDs.
1460      if (!isdigit(*IDStart) || (Val == 0 && errno == EINVAL)) {
1461        llvm_report_error("Bad $ operand number in inline asm string: '"
1462                          + std::string(AsmStr) + "'");
1463      }
1464      LastEmitted = IDEnd;
1465
1466      char Modifier[2] = { 0, 0 };
1467
1468      if (HasCurlyBraces) {
1469        // If we have curly braces, check for a modifier character.  This
1470        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
1471        if (*LastEmitted == ':') {
1472          ++LastEmitted;    // Consume ':' character.
1473          if (*LastEmitted == 0) {
1474            llvm_report_error("Bad ${:} expression in inline asm string: '"
1475                              + std::string(AsmStr) + "'");
1476          }
1477
1478          Modifier[0] = *LastEmitted;
1479          ++LastEmitted;    // Consume modifier character.
1480        }
1481
1482        if (*LastEmitted != '}') {
1483          llvm_report_error("Bad ${} expression in inline asm string: '"
1484                            + std::string(AsmStr) + "'");
1485        }
1486        ++LastEmitted;    // Consume '}' character.
1487      }
1488
1489      if ((unsigned)Val >= NumOperands-1) {
1490        llvm_report_error("Invalid $ operand number in inline asm string: '"
1491                          + std::string(AsmStr) + "'");
1492      }
1493
1494      // Okay, we finally have a value number.  Ask the target to print this
1495      // operand!
1496      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
1497        unsigned OpNo = 1;
1498
1499        bool Error = false;
1500
1501        // Scan to find the machine operand number for the operand.
1502        for (; Val; --Val) {
1503          if (OpNo >= MI->getNumOperands()) break;
1504          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1505          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
1506        }
1507
1508        if (OpNo >= MI->getNumOperands()) {
1509          Error = true;
1510        } else {
1511          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1512          ++OpNo;  // Skip over the ID number.
1513
1514          if (Modifier[0] == 'l')  // labels are target independent
1515            O << *MI->getOperand(OpNo).getMBB()->getSymbol();
1516          else {
1517            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
1518            if ((OpFlags & 7) == 4) {
1519              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
1520                                                Modifier[0] ? Modifier : 0);
1521            } else {
1522              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
1523                                          Modifier[0] ? Modifier : 0);
1524            }
1525          }
1526        }
1527        if (Error) {
1528          std::string msg;
1529          raw_string_ostream Msg(msg);
1530          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
1531          MI->print(Msg);
1532          llvm_report_error(Msg.str());
1533        }
1534      }
1535      break;
1536    }
1537    }
1538  }
1539  O << "\n\t" << MAI->getCommentString() << MAI->getInlineAsmEnd();
1540  OutStreamer.AddBlankLine();
1541}
1542
1543/// printImplicitDef - This method prints the specified machine instruction
1544/// that is an implicit def.
1545void AsmPrinter::printImplicitDef(const MachineInstr *MI) const {
1546  if (!VerboseAsm) return;
1547  O.PadToColumn(MAI->getCommentColumn());
1548  O << MAI->getCommentString() << " implicit-def: "
1549    << TRI->getName(MI->getOperand(0).getReg());
1550  OutStreamer.AddBlankLine();
1551}
1552
1553void AsmPrinter::printKill(const MachineInstr *MI) const {
1554  if (!VerboseAsm) return;
1555  O.PadToColumn(MAI->getCommentColumn());
1556  O << MAI->getCommentString() << " kill:";
1557  for (unsigned n = 0, e = MI->getNumOperands(); n != e; ++n) {
1558    const MachineOperand &op = MI->getOperand(n);
1559    assert(op.isReg() && "KILL instruction must have only register operands");
1560    O << ' ' << TRI->getName(op.getReg()) << (op.isDef() ? "<def>" : "<kill>");
1561  }
1562  OutStreamer.AddBlankLine();
1563}
1564
1565/// printLabel - This method prints a local label used by debug and
1566/// exception handling tables.
1567void AsmPrinter::printLabelInst(const MachineInstr *MI) const {
1568  OutStreamer.EmitLabel(MI->getOperand(0).getMCSymbol());
1569}
1570
1571/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
1572/// instruction, using the specified assembler variant.  Targets should
1573/// override this to format as appropriate.
1574bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
1575                                 unsigned AsmVariant, const char *ExtraCode) {
1576  // Target doesn't support this yet!
1577  return true;
1578}
1579
1580bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
1581                                       unsigned AsmVariant,
1582                                       const char *ExtraCode) {
1583  // Target doesn't support this yet!
1584  return true;
1585}
1586
1587MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
1588  return MMI->getAddrLabelSymbol(BA->getBasicBlock());
1589}
1590
1591MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
1592  return MMI->getAddrLabelSymbol(BB);
1593}
1594
1595/// GetCPISymbol - Return the symbol for the specified constant pool entry.
1596MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1597  return OutContext.GetOrCreateTemporarySymbol
1598    (Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
1599     + "_" + Twine(CPID));
1600}
1601
1602/// GetJTISymbol - Return the symbol for the specified jump table entry.
1603MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1604  return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
1605}
1606
1607/// GetJTSetSymbol - Return the symbol for the specified jump table .set
1608/// FIXME: privatize to AsmPrinter.
1609MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
1610  return OutContext.GetOrCreateTemporarySymbol
1611  (Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
1612   Twine(UID) + "_set_" + Twine(MBBID));
1613}
1614
1615/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1616/// global value name as its base, with the specified suffix, and where the
1617/// symbol is forced to have private linkage if ForcePrivate is true.
1618MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1619                                                   StringRef Suffix,
1620                                                   bool ForcePrivate) const {
1621  SmallString<60> NameStr;
1622  Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1623  NameStr.append(Suffix.begin(), Suffix.end());
1624  if (!GV->hasPrivateLinkage() && !ForcePrivate)
1625    return OutContext.GetOrCreateSymbol(NameStr.str());
1626  return OutContext.GetOrCreateTemporarySymbol(NameStr.str());
1627}
1628
1629/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1630/// ExternalSymbol.
1631MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1632  SmallString<60> NameStr;
1633  Mang->getNameWithPrefix(NameStr, Sym);
1634  return OutContext.GetOrCreateSymbol(NameStr.str());
1635}
1636
1637
1638
1639/// PrintParentLoopComment - Print comments about parent loops of this one.
1640static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1641                                   unsigned FunctionNumber) {
1642  if (Loop == 0) return;
1643  PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1644  OS.indent(Loop->getLoopDepth()*2)
1645    << "Parent Loop BB" << FunctionNumber << "_"
1646    << Loop->getHeader()->getNumber()
1647    << " Depth=" << Loop->getLoopDepth() << '\n';
1648}
1649
1650
1651/// PrintChildLoopComment - Print comments about child loops within
1652/// the loop for this basic block, with nesting.
1653static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1654                                  unsigned FunctionNumber) {
1655  // Add child loop information
1656  for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1657    OS.indent((*CL)->getLoopDepth()*2)
1658      << "Child Loop BB" << FunctionNumber << "_"
1659      << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1660      << '\n';
1661    PrintChildLoopComment(OS, *CL, FunctionNumber);
1662  }
1663}
1664
1665/// PrintBasicBlockLoopComments - Pretty-print comments for basic blocks.
1666static void PrintBasicBlockLoopComments(const MachineBasicBlock &MBB,
1667                                        const MachineLoopInfo *LI,
1668                                        const AsmPrinter &AP) {
1669  // Add loop depth information
1670  const MachineLoop *Loop = LI->getLoopFor(&MBB);
1671  if (Loop == 0) return;
1672
1673  MachineBasicBlock *Header = Loop->getHeader();
1674  assert(Header && "No header for loop");
1675
1676  // If this block is not a loop header, just print out what is the loop header
1677  // and return.
1678  if (Header != &MBB) {
1679    AP.OutStreamer.AddComment("  in Loop: Header=BB" +
1680                              Twine(AP.getFunctionNumber())+"_" +
1681                              Twine(Loop->getHeader()->getNumber())+
1682                              " Depth="+Twine(Loop->getLoopDepth()));
1683    return;
1684  }
1685
1686  // Otherwise, it is a loop header.  Print out information about child and
1687  // parent loops.
1688  raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1689
1690  PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1691
1692  OS << "=>";
1693  OS.indent(Loop->getLoopDepth()*2-2);
1694
1695  OS << "This ";
1696  if (Loop->empty())
1697    OS << "Inner ";
1698  OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1699
1700  PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1701}
1702
1703
1704/// EmitBasicBlockStart - This method prints the label for the specified
1705/// MachineBasicBlock, an alignment (if present) and a comment describing
1706/// it if appropriate.
1707void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1708  // Emit an alignment directive for this block, if needed.
1709  if (unsigned Align = MBB->getAlignment())
1710    EmitAlignment(Log2_32(Align));
1711
1712  // If the block has its address taken, emit any labels that were used to
1713  // reference the block.  It is possible that there is more than one label
1714  // here, because multiple LLVM BB's may have been RAUW'd to this block after
1715  // the references were generated.
1716  if (MBB->hasAddressTaken()) {
1717    const BasicBlock *BB = MBB->getBasicBlock();
1718    if (VerboseAsm)
1719      OutStreamer.AddComment("Block address taken");
1720
1721    std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
1722
1723    for (unsigned i = 0, e = Syms.size(); i != e; ++i)
1724      OutStreamer.EmitLabel(Syms[i]);
1725  }
1726
1727  // Print the main label for the block.
1728  if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
1729    if (VerboseAsm) {
1730      // NOTE: Want this comment at start of line.
1731      O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
1732      if (const BasicBlock *BB = MBB->getBasicBlock())
1733        if (BB->hasName())
1734          OutStreamer.AddComment("%" + BB->getName());
1735
1736      PrintBasicBlockLoopComments(*MBB, LI, *this);
1737      OutStreamer.AddBlankLine();
1738    }
1739  } else {
1740    if (VerboseAsm) {
1741      if (const BasicBlock *BB = MBB->getBasicBlock())
1742        if (BB->hasName())
1743          OutStreamer.AddComment("%" + BB->getName());
1744      PrintBasicBlockLoopComments(*MBB, LI, *this);
1745    }
1746
1747    OutStreamer.EmitLabel(MBB->getSymbol());
1748  }
1749}
1750
1751void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility) const {
1752  MCSymbolAttr Attr = MCSA_Invalid;
1753
1754  switch (Visibility) {
1755  default: break;
1756  case GlobalValue::HiddenVisibility:
1757    Attr = MAI->getHiddenVisibilityAttr();
1758    break;
1759  case GlobalValue::ProtectedVisibility:
1760    Attr = MAI->getProtectedVisibilityAttr();
1761    break;
1762  }
1763
1764  if (Attr != MCSA_Invalid)
1765    OutStreamer.EmitSymbolAttribute(Sym, Attr);
1766}
1767
1768void AsmPrinter::printOffset(int64_t Offset) const {
1769  if (Offset > 0)
1770    O << '+' << Offset;
1771  else if (Offset < 0)
1772    O << Offset;
1773}
1774
1775/// isBlockOnlyReachableByFallthough - Return true if the basic block has
1776/// exactly one predecessor and the control transfer mechanism between
1777/// the predecessor and this block is a fall-through.
1778bool AsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB)
1779    const {
1780  // If this is a landing pad, it isn't a fall through.  If it has no preds,
1781  // then nothing falls through to it.
1782  if (MBB->isLandingPad() || MBB->pred_empty())
1783    return false;
1784
1785  // If there isn't exactly one predecessor, it can't be a fall through.
1786  MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
1787  ++PI2;
1788  if (PI2 != MBB->pred_end())
1789    return false;
1790
1791  // The predecessor has to be immediately before this block.
1792  const MachineBasicBlock *Pred = *PI;
1793
1794  if (!Pred->isLayoutSuccessor(MBB))
1795    return false;
1796
1797  // If the block is completely empty, then it definitely does fall through.
1798  if (Pred->empty())
1799    return true;
1800
1801  // Otherwise, check the last instruction.
1802  const MachineInstr &LastInst = Pred->back();
1803  return !LastInst.getDesc().isBarrier();
1804}
1805
1806
1807
1808GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1809  if (!S->usesMetadata())
1810    return 0;
1811
1812  gcp_iterator GCPI = GCMetadataPrinters.find(S);
1813  if (GCPI != GCMetadataPrinters.end())
1814    return GCPI->second;
1815
1816  const char *Name = S->getName().c_str();
1817
1818  for (GCMetadataPrinterRegistry::iterator
1819         I = GCMetadataPrinterRegistry::begin(),
1820         E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1821    if (strcmp(Name, I->getName()) == 0) {
1822      GCMetadataPrinter *GMP = I->instantiate();
1823      GMP->S = S;
1824      GCMetadataPrinters.insert(std::make_pair(S, GMP));
1825      return GMP;
1826    }
1827
1828  llvm_report_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
1829  return 0;
1830}
1831
1832