AsmPrinter.cpp revision 29814c4ecbee79b025c92fb295e39bcf62877ebe 
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#include "llvm/CodeGen/AsmPrinter.h"
15#include "llvm/Assembly/Writer.h"
16#include "llvm/DerivedTypes.h"
17#include "llvm/Constants.h"
18#include "llvm/Module.h"
19#include "llvm/CodeGen/DwarfWriter.h"
20#include "llvm/CodeGen/GCMetadataPrinter.h"
21#include "llvm/CodeGen/MachineConstantPool.h"
22#include "llvm/CodeGen/MachineFrameInfo.h"
23#include "llvm/CodeGen/MachineFunction.h"
24#include "llvm/CodeGen/MachineJumpTableInfo.h"
25#include "llvm/CodeGen/MachineLoopInfo.h"
26#include "llvm/CodeGen/MachineModuleInfo.h"
27#include "llvm/Analysis/DebugInfo.h"
28#include "llvm/MC/MCContext.h"
29#include "llvm/MC/MCExpr.h"
30#include "llvm/MC/MCInst.h"
31#include "llvm/MC/MCSection.h"
32#include "llvm/MC/MCStreamer.h"
33#include "llvm/MC/MCSymbol.h"
34#include "llvm/Support/CommandLine.h"
35#include "llvm/Support/ErrorHandling.h"
36#include "llvm/Support/Format.h"
37#include "llvm/Support/FormattedStream.h"
38#include "llvm/MC/MCAsmInfo.h"
39#include "llvm/Target/Mangler.h"
40#include "llvm/Target/TargetData.h"
41#include "llvm/Target/TargetInstrInfo.h"
42#include "llvm/Target/TargetLowering.h"
43#include "llvm/Target/TargetLoweringObjectFile.h"
44#include "llvm/Target/TargetOptions.h"
45#include "llvm/Target/TargetRegisterInfo.h"
46#include "llvm/ADT/SmallPtrSet.h"
47#include "llvm/ADT/SmallString.h"
48#include <cerrno>
49using namespace llvm;
50
51static cl::opt<cl::boolOrDefault>
52AsmVerbose("asm-verbose", cl::desc("Add comments to directives."),
53           cl::init(cl::BOU_UNSET));
54
55static bool getVerboseAsm(bool VDef) {
56  switch (AsmVerbose) {
57  default:
58  case cl::BOU_UNSET: return VDef;
59  case cl::BOU_TRUE:  return true;
60  case cl::BOU_FALSE: return false;
61  }
62}
63
64char AsmPrinter::ID = 0;
65AsmPrinter::AsmPrinter(formatted_raw_ostream &o, TargetMachine &tm,
66                       const MCAsmInfo *T, bool VDef)
67  : MachineFunctionPass(&ID), FunctionNumber(0), O(o),
68    TM(tm), MAI(T), TRI(tm.getRegisterInfo()),
69
70    OutContext(*new MCContext()),
71    // FIXME: Pass instprinter to streamer.
72    OutStreamer(*createAsmStreamer(OutContext, O, *T,
73                                   TM.getTargetData()->isLittleEndian(),
74                                   getVerboseAsm(VDef), 0)),
75
76    LastMI(0), LastFn(0), Counter(~0U), PrevDLT(NULL) {
77  DW = 0; MMI = 0;
78  VerboseAsm = getVerboseAsm(VDef);
79}
80
81AsmPrinter::~AsmPrinter() {
82  for (gcp_iterator I = GCMetadataPrinters.begin(),
83                    E = GCMetadataPrinters.end(); I != E; ++I)
84    delete I->second;
85
86  delete &OutStreamer;
87  delete &OutContext;
88}
89
90TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
91  return TM.getTargetLowering()->getObjFileLowering();
92}
93
94/// getCurrentSection() - Return the current section we are emitting to.
95const MCSection *AsmPrinter::getCurrentSection() const {
96  return OutStreamer.getCurrentSection();
97}
98
99
100void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
101  AU.setPreservesAll();
102  MachineFunctionPass::getAnalysisUsage(AU);
103  AU.addRequired<GCModuleInfo>();
104  if (VerboseAsm)
105    AU.addRequired<MachineLoopInfo>();
106}
107
108bool AsmPrinter::doInitialization(Module &M) {
109  // Initialize TargetLoweringObjectFile.
110  const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
111    .Initialize(OutContext, TM);
112
113  Mang = new Mangler(*MAI);
114
115  // Allow the target to emit any magic that it wants at the start of the file.
116  EmitStartOfAsmFile(M);
117
118  // Very minimal debug info. It is ignored if we emit actual debug info. If we
119  // don't, this at least helps the user find where a global came from.
120  if (MAI->hasSingleParameterDotFile()) {
121    // .file "foo.c"
122    OutStreamer.EmitFileDirective(M.getModuleIdentifier());
123  }
124
125  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
126  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
127  for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
128    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
129      MP->beginAssembly(O, *this, *MAI);
130
131  if (!M.getModuleInlineAsm().empty())
132    O << MAI->getCommentString() << " Start of file scope inline assembly\n"
133      << M.getModuleInlineAsm()
134      << '\n' << MAI->getCommentString()
135      << " End of file scope inline assembly\n";
136
137  MMI = getAnalysisIfAvailable<MachineModuleInfo>();
138  if (MMI)
139    MMI->AnalyzeModule(M);
140  DW = getAnalysisIfAvailable<DwarfWriter>();
141  if (DW)
142    DW->BeginModule(&M, MMI, O, this, MAI);
143
144  return false;
145}
146
147/// EmitGlobalVariable - Emit the specified global variable to the .s file.
148void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
149  if (!GV->hasInitializer())   // External globals require no code.
150    return;
151
152  // Check to see if this is a special global used by LLVM, if so, emit it.
153  if (EmitSpecialLLVMGlobal(GV))
154    return;
155
156  MCSymbol *GVSym = GetGlobalValueSymbol(GV);
157  printVisibility(GVSym, GV->getVisibility());
158
159  if (MAI->hasDotTypeDotSizeDirective())
160    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
161
162  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
163
164  const TargetData *TD = TM.getTargetData();
165  unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType());
166  unsigned AlignLog = TD->getPreferredAlignmentLog(GV);
167
168  // Handle common and BSS local symbols (.lcomm).
169  if (GVKind.isCommon() || GVKind.isBSSLocal()) {
170    if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
171
172    if (VerboseAsm) {
173      WriteAsOperand(OutStreamer.GetCommentOS(), GV,
174                     /*PrintType=*/false, GV->getParent());
175      OutStreamer.GetCommentOS() << '\n';
176    }
177
178    // Handle common symbols.
179    if (GVKind.isCommon()) {
180      // .comm _foo, 42, 4
181      OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
182      return;
183    }
184
185    // Handle local BSS symbols.
186    if (MAI->hasMachoZeroFillDirective()) {
187      const MCSection *TheSection =
188        getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
189      // .zerofill __DATA, __bss, _foo, 400, 5
190      OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
191      return;
192    }
193
194    if (MAI->hasLCOMMDirective()) {
195      // .lcomm _foo, 42
196      OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
197      return;
198    }
199
200    // .local _foo
201    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
202    // .comm _foo, 42, 4
203    OutStreamer.EmitCommonSymbol(GVSym, Size, 1 << AlignLog);
204    return;
205  }
206
207  const MCSection *TheSection =
208    getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
209
210  // Handle the zerofill directive on darwin, which is a special form of BSS
211  // emission.
212  if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
213    // .globl _foo
214    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
215    // .zerofill __DATA, __common, _foo, 400, 5
216    OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
217    return;
218  }
219
220  OutStreamer.SwitchSection(TheSection);
221
222  // TODO: Factor into an 'emit linkage' thing that is shared with function
223  // bodies.
224  switch (GV->getLinkage()) {
225  case GlobalValue::CommonLinkage:
226  case GlobalValue::LinkOnceAnyLinkage:
227  case GlobalValue::LinkOnceODRLinkage:
228  case GlobalValue::WeakAnyLinkage:
229  case GlobalValue::WeakODRLinkage:
230  case GlobalValue::LinkerPrivateLinkage:
231    if (MAI->getWeakDefDirective() != 0) {
232      // .globl _foo
233      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
234      // .weak_definition _foo
235      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
236    } else if (const char *LinkOnce = MAI->getLinkOnceDirective()) {
237      // .globl _foo
238      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
239      // FIXME: linkonce should be a section attribute, handled by COFF Section
240      // assignment.
241      // http://sourceware.org/binutils/docs-2.20/as/Linkonce.html#Linkonce
242      // .linkonce same_size
243      O << LinkOnce;
244    } else {
245      // .weak _foo
246      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
247    }
248    break;
249  case GlobalValue::DLLExportLinkage:
250  case GlobalValue::AppendingLinkage:
251    // FIXME: appending linkage variables should go into a section of
252    // their name or something.  For now, just emit them as external.
253  case GlobalValue::ExternalLinkage:
254    // If external or appending, declare as a global symbol.
255    // .globl _foo
256    OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
257    break;
258  case GlobalValue::PrivateLinkage:
259  case GlobalValue::InternalLinkage:
260     break;
261  default:
262    llvm_unreachable("Unknown linkage type!");
263  }
264
265  EmitAlignment(AlignLog, GV);
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
283bool AsmPrinter::doFinalization(Module &M) {
284  // Emit global variables.
285  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
286       I != E; ++I)
287    EmitGlobalVariable(I);
288
289  // Emit final debug information.
290  if (MAI->doesSupportDebugInformation() || MAI->doesSupportExceptionHandling())
291    DW->EndModule();
292
293  // If the target wants to know about weak references, print them all.
294  if (MAI->getWeakRefDirective()) {
295    // FIXME: This is not lazy, it would be nice to only print weak references
296    // to stuff that is actually used.  Note that doing so would require targets
297    // to notice uses in operands (due to constant exprs etc).  This should
298    // happen with the MC stuff eventually.
299
300    // Print out module-level global variables here.
301    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
302         I != E; ++I) {
303      if (!I->hasExternalWeakLinkage()) continue;
304      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(I),
305                                      MCSA_WeakReference);
306    }
307
308    for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
309      if (!I->hasExternalWeakLinkage()) continue;
310      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(I),
311                                      MCSA_WeakReference);
312    }
313  }
314
315  if (MAI->getSetDirective()) {
316    OutStreamer.AddBlankLine();
317    for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
318         I != E; ++I) {
319      MCSymbol *Name = GetGlobalValueSymbol(I);
320
321      const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
322      MCSymbol *Target = GetGlobalValueSymbol(GV);
323
324      if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
325        OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
326      else if (I->hasWeakLinkage())
327        OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
328      else
329        assert(I->hasLocalLinkage() && "Invalid alias linkage");
330
331      printVisibility(Name, I->getVisibility());
332
333      O << MAI->getSetDirective() << ' ' << *Name << ", " << *Target << '\n';
334    }
335  }
336
337  GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
338  assert(MI && "AsmPrinter didn't require GCModuleInfo?");
339  for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
340    if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
341      MP->finishAssembly(O, *this, *MAI);
342
343  // If we don't have any trampolines, then we don't require stack memory
344  // to be executable. Some targets have a directive to declare this.
345  Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
346  if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
347    if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
348      OutStreamer.SwitchSection(S);
349
350  // Allow the target to emit any magic that it wants at the end of the file,
351  // after everything else has gone out.
352  EmitEndOfAsmFile(M);
353
354  delete Mang; Mang = 0;
355  DW = 0; MMI = 0;
356
357  OutStreamer.Finish();
358  return false;
359}
360
361void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
362  // Get the function symbol.
363  CurrentFnSym = GetGlobalValueSymbol(MF.getFunction());
364  IncrementFunctionNumber();
365
366  if (VerboseAsm)
367    LI = &getAnalysis<MachineLoopInfo>();
368}
369
370namespace {
371  // SectionCPs - Keep track the alignment, constpool entries per Section.
372  struct SectionCPs {
373    const MCSection *S;
374    unsigned Alignment;
375    SmallVector<unsigned, 4> CPEs;
376    SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
377  };
378}
379
380/// EmitConstantPool - Print to the current output stream assembly
381/// representations of the constants in the constant pool MCP. This is
382/// used to print out constants which have been "spilled to memory" by
383/// the code generator.
384///
385void AsmPrinter::EmitConstantPool(MachineConstantPool *MCP) {
386  const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
387  if (CP.empty()) return;
388
389  // Calculate sections for constant pool entries. We collect entries to go into
390  // the same section together to reduce amount of section switch statements.
391  SmallVector<SectionCPs, 4> CPSections;
392  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
393    const MachineConstantPoolEntry &CPE = CP[i];
394    unsigned Align = CPE.getAlignment();
395
396    SectionKind Kind;
397    switch (CPE.getRelocationInfo()) {
398    default: llvm_unreachable("Unknown section kind");
399    case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
400    case 1:
401      Kind = SectionKind::getReadOnlyWithRelLocal();
402      break;
403    case 0:
404    switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
405    case 4:  Kind = SectionKind::getMergeableConst4(); break;
406    case 8:  Kind = SectionKind::getMergeableConst8(); break;
407    case 16: Kind = SectionKind::getMergeableConst16();break;
408    default: Kind = SectionKind::getMergeableConst(); break;
409    }
410    }
411
412    const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
413
414    // The number of sections are small, just do a linear search from the
415    // last section to the first.
416    bool Found = false;
417    unsigned SecIdx = CPSections.size();
418    while (SecIdx != 0) {
419      if (CPSections[--SecIdx].S == S) {
420        Found = true;
421        break;
422      }
423    }
424    if (!Found) {
425      SecIdx = CPSections.size();
426      CPSections.push_back(SectionCPs(S, Align));
427    }
428
429    if (Align > CPSections[SecIdx].Alignment)
430      CPSections[SecIdx].Alignment = Align;
431    CPSections[SecIdx].CPEs.push_back(i);
432  }
433
434  // Now print stuff into the calculated sections.
435  for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
436    OutStreamer.SwitchSection(CPSections[i].S);
437    EmitAlignment(Log2_32(CPSections[i].Alignment));
438
439    unsigned Offset = 0;
440    for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
441      unsigned CPI = CPSections[i].CPEs[j];
442      MachineConstantPoolEntry CPE = CP[CPI];
443
444      // Emit inter-object padding for alignment.
445      unsigned AlignMask = CPE.getAlignment() - 1;
446      unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
447      OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
448
449      const Type *Ty = CPE.getType();
450      Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
451
452      // Emit the label with a comment on it.
453      if (VerboseAsm) {
454        OutStreamer.GetCommentOS() << "constant pool ";
455        WriteTypeSymbolic(OutStreamer.GetCommentOS(), CPE.getType(),
456                          MF->getFunction()->getParent());
457        OutStreamer.GetCommentOS() << '\n';
458      }
459      OutStreamer.EmitLabel(GetCPISymbol(CPI));
460
461      if (CPE.isMachineConstantPoolEntry())
462        EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
463      else
464        EmitGlobalConstant(CPE.Val.ConstVal);
465    }
466  }
467}
468
469/// EmitJumpTableInfo - Print assembly representations of the jump tables used
470/// by the current function to the current output stream.
471///
472void AsmPrinter::EmitJumpTableInfo(MachineJumpTableInfo *MJTI,
473                                   MachineFunction &MF) {
474  const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
475  if (JT.empty()) return;
476
477  bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
478
479  // Pick the directive to use to print the jump table entries, and switch to
480  // the appropriate section.
481  TargetLowering *LoweringInfo = TM.getTargetLowering();
482
483  const Function *F = MF.getFunction();
484  bool JTInDiffSection = false;
485  if (F->isWeakForLinker() ||
486      (IsPic && !LoweringInfo->usesGlobalOffsetTable())) {
487    // In PIC mode, we need to emit the jump table to the same section as the
488    // function body itself, otherwise the label differences won't make sense.
489    // We should also do if the section name is NULL or function is declared in
490    // discardable section.
491    OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang,
492                                                                    TM));
493  } else {
494    // Otherwise, drop it in the readonly section.
495    const MCSection *ReadOnlySection =
496      getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
497    OutStreamer.SwitchSection(ReadOnlySection);
498    JTInDiffSection = true;
499  }
500
501  EmitAlignment(Log2_32(MJTI->getAlignment()));
502
503  for (unsigned i = 0, e = JT.size(); i != e; ++i) {
504    const std::vector<MachineBasicBlock*> &JTBBs = JT[i].MBBs;
505
506    // If this jump table was deleted, ignore it.
507    if (JTBBs.empty()) continue;
508
509    // For PIC codegen, if possible we want to use the SetDirective to reduce
510    // the number of relocations the assembler will generate for the jump table.
511    // Set directives are all printed before the jump table itself.
512    SmallPtrSet<MachineBasicBlock*, 16> EmittedSets;
513    if (MAI->getSetDirective() && IsPic)
514      for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
515        if (EmittedSets.insert(JTBBs[ii]))
516          printPICJumpTableSetLabel(i, JTBBs[ii]);
517
518    // On some targets (e.g. Darwin) we want to emit two consequtive labels
519    // before each jump table.  The first label is never referenced, but tells
520    // the assembler and linker the extents of the jump table object.  The
521    // second label is actually referenced by the code.
522    if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
523      OutStreamer.EmitLabel(GetJTISymbol(i, true));
524
525    OutStreamer.EmitLabel(GetJTISymbol(i));
526
527    for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
528      printPICJumpTableEntry(MJTI, JTBBs[ii], i);
529      O << '\n';
530    }
531  }
532}
533
534void AsmPrinter::printPICJumpTableEntry(const MachineJumpTableInfo *MJTI,
535                                        const MachineBasicBlock *MBB,
536                                        unsigned uid)  const {
537  bool isPIC = TM.getRelocationModel() == Reloc::PIC_;
538
539  // Use JumpTableDirective otherwise honor the entry size from the jump table
540  // info.
541  const char *JTEntryDirective = 0;
542  if (isPIC) JTEntryDirective = MAI->getPICJumpTableDirective();
543  bool HadJTEntryDirective = JTEntryDirective != NULL;
544  if (!HadJTEntryDirective) {
545    JTEntryDirective = MJTI->getEntrySize() == 4 ?
546      MAI->getData32bitsDirective() : MAI->getData64bitsDirective();
547  }
548
549  O << JTEntryDirective << ' ';
550
551  // If we have emitted set directives for the jump table entries, print
552  // them rather than the entries themselves.  If we're emitting PIC, then
553  // emit the table entries as differences between two text section labels.
554  // If we're emitting non-PIC code, then emit the entries as direct
555  // references to the target basic blocks.
556  if (!isPIC) {
557    O << *GetMBBSymbol(MBB->getNumber());
558  } else if (MAI->getSetDirective()) {
559    O << MAI->getPrivateGlobalPrefix() << getFunctionNumber()
560      << '_' << uid << "_set_" << MBB->getNumber();
561  } else {
562    O << *GetMBBSymbol(MBB->getNumber());
563    // If the arch uses custom Jump Table directives, don't calc relative to
564    // JT.
565    if (!HadJTEntryDirective)
566      O << '-' << *GetJTISymbol(uid);
567  }
568}
569
570
571/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
572/// special global used by LLVM.  If so, emit it and return true, otherwise
573/// do nothing and return false.
574bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
575  if (GV->getName() == "llvm.used") {
576    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
577      EmitLLVMUsedList(GV->getInitializer());
578    return true;
579  }
580
581  // Ignore debug and non-emitted data.  This handles llvm.compiler.used.
582  if (GV->getSection() == "llvm.metadata" ||
583      GV->hasAvailableExternallyLinkage())
584    return true;
585
586  if (!GV->hasAppendingLinkage()) return false;
587
588  assert(GV->hasInitializer() && "Not a special LLVM global!");
589
590  const TargetData *TD = TM.getTargetData();
591  unsigned Align = Log2_32(TD->getPointerPrefAlignment());
592  if (GV->getName() == "llvm.global_ctors") {
593    OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
594    EmitAlignment(Align, 0);
595    EmitXXStructorList(GV->getInitializer());
596
597    if (TM.getRelocationModel() == Reloc::Static &&
598        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
599      StringRef Sym(".constructors_used");
600      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
601                                      MCSA_Reference);
602    }
603    return true;
604  }
605
606  if (GV->getName() == "llvm.global_dtors") {
607    OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
608    EmitAlignment(Align, 0);
609    EmitXXStructorList(GV->getInitializer());
610
611    if (TM.getRelocationModel() == Reloc::Static &&
612        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
613      StringRef Sym(".destructors_used");
614      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
615                                      MCSA_Reference);
616    }
617    return true;
618  }
619
620  return false;
621}
622
623/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
624/// global in the specified llvm.used list for which emitUsedDirectiveFor
625/// is true, as being used with this directive.
626void AsmPrinter::EmitLLVMUsedList(Constant *List) {
627  // Should be an array of 'i8*'.
628  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
629  if (InitList == 0) return;
630
631  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
632    const GlobalValue *GV =
633      dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
634    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
635      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(GV),
636                                      MCSA_NoDeadStrip);
637  }
638}
639
640/// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the
641/// function pointers, ignoring the init priority.
642void AsmPrinter::EmitXXStructorList(Constant *List) {
643  // Should be an array of '{ int, void ()* }' structs.  The first value is the
644  // init priority, which we ignore.
645  if (!isa<ConstantArray>(List)) return;
646  ConstantArray *InitList = cast<ConstantArray>(List);
647  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
648    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
649      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
650
651      if (CS->getOperand(1)->isNullValue())
652        return;  // Found a null terminator, exit printing.
653      // Emit the function pointer.
654      EmitGlobalConstant(CS->getOperand(1));
655    }
656}
657
658//===--------------------------------------------------------------------===//
659// Emission and print routines
660//
661
662/// EmitInt8 - Emit a byte directive and value.
663///
664void AsmPrinter::EmitInt8(int Value) const {
665  OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
666}
667
668/// EmitInt16 - Emit a short directive and value.
669///
670void AsmPrinter::EmitInt16(int Value) const {
671  OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
672}
673
674/// EmitInt32 - Emit a long directive and value.
675///
676void AsmPrinter::EmitInt32(int Value) const {
677  OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
678}
679
680/// EmitInt64 - Emit a long long directive and value.
681///
682void AsmPrinter::EmitInt64(uint64_t Value) const {
683  OutStreamer.EmitIntValue(Value, 8, 0/*addrspace*/);
684}
685
686//===----------------------------------------------------------------------===//
687
688// EmitAlignment - Emit an alignment directive to the specified power of
689// two boundary.  For example, if you pass in 3 here, you will get an 8
690// byte alignment.  If a global value is specified, and if that global has
691// an explicit alignment requested, it will unconditionally override the
692// alignment request.  However, if ForcedAlignBits is specified, this value
693// has final say: the ultimate alignment will be the max of ForcedAlignBits
694// and the alignment computed with NumBits and the global.
695//
696// The algorithm is:
697//     Align = NumBits;
698//     if (GV && GV->hasalignment) Align = GV->getalignment();
699//     Align = std::max(Align, ForcedAlignBits);
700//
701void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
702                               unsigned ForcedAlignBits,
703                               bool UseFillExpr) const {
704  if (GV && GV->getAlignment())
705    NumBits = Log2_32(GV->getAlignment());
706  NumBits = std::max(NumBits, ForcedAlignBits);
707
708  if (NumBits == 0) return;   // No need to emit alignment.
709
710  unsigned FillValue = 0;
711  if (getCurrentSection()->getKind().isText())
712    FillValue = MAI->getTextAlignFillValue();
713
714  OutStreamer.EmitValueToAlignment(1 << NumBits, FillValue, 1, 0);
715}
716
717/// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
718///
719static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
720  MCContext &Ctx = AP.OutContext;
721
722  if (CV->isNullValue() || isa<UndefValue>(CV))
723    return MCConstantExpr::Create(0, Ctx);
724
725  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
726    return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
727
728  if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
729    return MCSymbolRefExpr::Create(AP.GetGlobalValueSymbol(GV), Ctx);
730  if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
731    return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
732
733  const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
734  if (CE == 0) {
735    llvm_unreachable("Unknown constant value to lower!");
736    return MCConstantExpr::Create(0, Ctx);
737  }
738
739  switch (CE->getOpcode()) {
740  case Instruction::ZExt:
741  case Instruction::SExt:
742  case Instruction::FPTrunc:
743  case Instruction::FPExt:
744  case Instruction::UIToFP:
745  case Instruction::SIToFP:
746  case Instruction::FPToUI:
747  case Instruction::FPToSI:
748  default: llvm_unreachable("FIXME: Don't support this constant cast expr");
749  case Instruction::GetElementPtr: {
750    const TargetData &TD = *AP.TM.getTargetData();
751    // Generate a symbolic expression for the byte address
752    const Constant *PtrVal = CE->getOperand(0);
753    SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
754    int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
755                                         IdxVec.size());
756
757    const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
758    if (Offset == 0)
759      return Base;
760
761    // Truncate/sext the offset to the pointer size.
762    if (TD.getPointerSizeInBits() != 64) {
763      int SExtAmount = 64-TD.getPointerSizeInBits();
764      Offset = (Offset << SExtAmount) >> SExtAmount;
765    }
766
767    return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
768                                   Ctx);
769  }
770
771  case Instruction::Trunc:
772    // We emit the value and depend on the assembler to truncate the generated
773    // expression properly.  This is important for differences between
774    // blockaddress labels.  Since the two labels are in the same function, it
775    // is reasonable to treat their delta as a 32-bit value.
776    // FALL THROUGH.
777  case Instruction::BitCast:
778    return LowerConstant(CE->getOperand(0), AP);
779
780  case Instruction::IntToPtr: {
781    const TargetData &TD = *AP.TM.getTargetData();
782    // Handle casts to pointers by changing them into casts to the appropriate
783    // integer type.  This promotes constant folding and simplifies this code.
784    Constant *Op = CE->getOperand(0);
785    Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
786                                      false/*ZExt*/);
787    return LowerConstant(Op, AP);
788  }
789
790  case Instruction::PtrToInt: {
791    const TargetData &TD = *AP.TM.getTargetData();
792    // Support only foldable casts to/from pointers that can be eliminated by
793    // changing the pointer to the appropriately sized integer type.
794    Constant *Op = CE->getOperand(0);
795    const Type *Ty = CE->getType();
796
797    const MCExpr *OpExpr = LowerConstant(Op, AP);
798
799    // We can emit the pointer value into this slot if the slot is an
800    // integer slot equal to the size of the pointer.
801    if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
802      return OpExpr;
803
804    // Otherwise the pointer is smaller than the resultant integer, mask off
805    // the high bits so we are sure to get a proper truncation if the input is
806    // a constant expr.
807    unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
808    const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
809    return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
810  }
811
812  case Instruction::Add:
813  case Instruction::Sub:
814  case Instruction::And:
815  case Instruction::Or:
816  case Instruction::Xor: {
817    const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
818    const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
819    switch (CE->getOpcode()) {
820    default: llvm_unreachable("Unknown binary operator constant cast expr");
821    case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
822    case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
823    case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
824    case Instruction::Or:  return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
825    case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
826    }
827  }
828  }
829}
830
831static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
832                                    AsmPrinter &AP) {
833  if (AddrSpace != 0 || !CA->isString()) {
834    // Not a string.  Print the values in successive locations
835    for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
836      AP.EmitGlobalConstant(CA->getOperand(i), AddrSpace);
837    return;
838  }
839
840  // Otherwise, it can be emitted as .ascii.
841  SmallVector<char, 128> TmpVec;
842  TmpVec.reserve(CA->getNumOperands());
843  for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
844    TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
845
846  AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
847}
848
849static void EmitGlobalConstantVector(const ConstantVector *CV,
850                                     unsigned AddrSpace, AsmPrinter &AP) {
851  for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
852    AP.EmitGlobalConstant(CV->getOperand(i), AddrSpace);
853}
854
855static void EmitGlobalConstantStruct(const ConstantStruct *CS,
856                                     unsigned AddrSpace, AsmPrinter &AP) {
857  // Print the fields in successive locations. Pad to align if needed!
858  const TargetData *TD = AP.TM.getTargetData();
859  unsigned Size = TD->getTypeAllocSize(CS->getType());
860  const StructLayout *Layout = TD->getStructLayout(CS->getType());
861  uint64_t SizeSoFar = 0;
862  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
863    const Constant *Field = CS->getOperand(i);
864
865    // Check if padding is needed and insert one or more 0s.
866    uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
867    uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
868                        - Layout->getElementOffset(i)) - FieldSize;
869    SizeSoFar += FieldSize + PadSize;
870
871    // Now print the actual field value.
872    AP.EmitGlobalConstant(Field, AddrSpace);
873
874    // Insert padding - this may include padding to increase the size of the
875    // current field up to the ABI size (if the struct is not packed) as well
876    // as padding to ensure that the next field starts at the right offset.
877    AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
878  }
879  assert(SizeSoFar == Layout->getSizeInBytes() &&
880         "Layout of constant struct may be incorrect!");
881}
882
883static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
884                                 AsmPrinter &AP) {
885  // FP Constants are printed as integer constants to avoid losing
886  // precision.
887  if (CFP->getType()->isDoubleTy()) {
888    if (AP.VerboseAsm) {
889      double Val = CFP->getValueAPF().convertToDouble();
890      AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
891    }
892
893    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
894    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
895    return;
896  }
897
898  if (CFP->getType()->isFloatTy()) {
899    if (AP.VerboseAsm) {
900      float Val = CFP->getValueAPF().convertToFloat();
901      AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
902    }
903    uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
904    AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
905    return;
906  }
907
908  if (CFP->getType()->isX86_FP80Ty()) {
909    // all long double variants are printed as hex
910    // api needed to prevent premature destruction
911    APInt API = CFP->getValueAPF().bitcastToAPInt();
912    const uint64_t *p = API.getRawData();
913    if (AP.VerboseAsm) {
914      // Convert to double so we can print the approximate val as a comment.
915      APFloat DoubleVal = CFP->getValueAPF();
916      bool ignored;
917      DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
918                        &ignored);
919      AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
920        << DoubleVal.convertToDouble() << '\n';
921    }
922
923    if (AP.TM.getTargetData()->isBigEndian()) {
924      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
925      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
926    } else {
927      AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
928      AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
929    }
930
931    // Emit the tail padding for the long double.
932    const TargetData &TD = *AP.TM.getTargetData();
933    AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
934                             TD.getTypeStoreSize(CFP->getType()), AddrSpace);
935    return;
936  }
937
938  assert(CFP->getType()->isPPC_FP128Ty() &&
939         "Floating point constant type not handled");
940  // All long double variants are printed as hex api needed to prevent
941  // premature destruction.
942  APInt API = CFP->getValueAPF().bitcastToAPInt();
943  const uint64_t *p = API.getRawData();
944  if (AP.TM.getTargetData()->isBigEndian()) {
945    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
946    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
947  } else {
948    AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
949    AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
950  }
951}
952
953static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
954                                       unsigned AddrSpace, AsmPrinter &AP) {
955  const TargetData *TD = AP.TM.getTargetData();
956  unsigned BitWidth = CI->getBitWidth();
957  assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
958
959  // We don't expect assemblers to support integer data directives
960  // for more than 64 bits, so we emit the data in at most 64-bit
961  // quantities at a time.
962  const uint64_t *RawData = CI->getValue().getRawData();
963  for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
964    uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
965    AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
966  }
967}
968
969/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
970void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
971  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
972    uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
973    return OutStreamer.EmitZeros(Size, AddrSpace);
974  }
975
976  if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
977    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
978    switch (Size) {
979    case 1:
980    case 2:
981    case 4:
982    case 8:
983      if (VerboseAsm)
984        OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
985      OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
986      return;
987    default:
988      EmitGlobalConstantLargeInt(CI, AddrSpace, *this);
989      return;
990    }
991  }
992
993  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
994    return EmitGlobalConstantArray(CVA, AddrSpace, *this);
995
996  if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
997    return EmitGlobalConstantStruct(CVS, AddrSpace, *this);
998
999  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1000    return EmitGlobalConstantFP(CFP, AddrSpace, *this);
1001
1002  if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
1003    return EmitGlobalConstantVector(V, AddrSpace, *this);
1004
1005  if (isa<ConstantPointerNull>(CV)) {
1006    unsigned Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
1007    OutStreamer.EmitIntValue(0, Size, AddrSpace);
1008    return;
1009  }
1010
1011  // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
1012  // thread the streamer with EmitValue.
1013  OutStreamer.EmitValue(LowerConstant(CV, *this),
1014                        TM.getTargetData()->getTypeAllocSize(CV->getType()),
1015                        AddrSpace);
1016}
1017
1018void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
1019  // Target doesn't support this yet!
1020  llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
1021}
1022
1023/// PrintSpecial - Print information related to the specified machine instr
1024/// that is independent of the operand, and may be independent of the instr
1025/// itself.  This can be useful for portably encoding the comment character
1026/// or other bits of target-specific knowledge into the asmstrings.  The
1027/// syntax used is ${:comment}.  Targets can override this to add support
1028/// for their own strange codes.
1029void AsmPrinter::PrintSpecial(const MachineInstr *MI, const char *Code) const {
1030  if (!strcmp(Code, "private")) {
1031    O << MAI->getPrivateGlobalPrefix();
1032  } else if (!strcmp(Code, "comment")) {
1033    if (VerboseAsm)
1034      O << MAI->getCommentString();
1035  } else if (!strcmp(Code, "uid")) {
1036    // Comparing the address of MI isn't sufficient, because machineinstrs may
1037    // be allocated to the same address across functions.
1038    const Function *ThisF = MI->getParent()->getParent()->getFunction();
1039
1040    // If this is a new LastFn instruction, bump the counter.
1041    if (LastMI != MI || LastFn != ThisF) {
1042      ++Counter;
1043      LastMI = MI;
1044      LastFn = ThisF;
1045    }
1046    O << Counter;
1047  } else {
1048    std::string msg;
1049    raw_string_ostream Msg(msg);
1050    Msg << "Unknown special formatter '" << Code
1051         << "' for machine instr: " << *MI;
1052    llvm_report_error(Msg.str());
1053  }
1054}
1055
1056/// processDebugLoc - Processes the debug information of each machine
1057/// instruction's DebugLoc.
1058void AsmPrinter::processDebugLoc(const MachineInstr *MI,
1059                                 bool BeforePrintingInsn) {
1060  if (!MAI || !DW || !MAI->doesSupportDebugInformation()
1061      || !DW->ShouldEmitDwarfDebug())
1062    return;
1063  DebugLoc DL = MI->getDebugLoc();
1064  if (DL.isUnknown())
1065    return;
1066  DILocation CurDLT = MF->getDILocation(DL);
1067  if (CurDLT.getScope().isNull())
1068    return;
1069
1070  if (!BeforePrintingInsn) {
1071    // After printing instruction
1072    DW->EndScope(MI);
1073  } else if (CurDLT.getNode() != PrevDLT) {
1074    unsigned L = DW->RecordSourceLine(CurDLT.getLineNumber(),
1075                                      CurDLT.getColumnNumber(),
1076                                      CurDLT.getScope().getNode());
1077    printLabel(L);
1078    O << '\n';
1079    DW->BeginScope(MI, L);
1080    PrevDLT = CurDLT.getNode();
1081  }
1082}
1083
1084
1085/// printInlineAsm - This method formats and prints the specified machine
1086/// instruction that is an inline asm.
1087void AsmPrinter::printInlineAsm(const MachineInstr *MI) const {
1088  unsigned NumOperands = MI->getNumOperands();
1089
1090  // Count the number of register definitions.
1091  unsigned NumDefs = 0;
1092  for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef();
1093       ++NumDefs)
1094    assert(NumDefs != NumOperands-1 && "No asm string?");
1095
1096  assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?");
1097
1098  // Disassemble the AsmStr, printing out the literal pieces, the operands, etc.
1099  const char *AsmStr = MI->getOperand(NumDefs).getSymbolName();
1100
1101  O << '\t';
1102
1103  // If this asmstr is empty, just print the #APP/#NOAPP markers.
1104  // These are useful to see where empty asm's wound up.
1105  if (AsmStr[0] == 0) {
1106    O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1107    O << MAI->getCommentString() << MAI->getInlineAsmEnd() << '\n';
1108    return;
1109  }
1110
1111  O << MAI->getCommentString() << MAI->getInlineAsmStart() << "\n\t";
1112
1113  // The variant of the current asmprinter.
1114  int AsmPrinterVariant = MAI->getAssemblerDialect();
1115
1116  int CurVariant = -1;            // The number of the {.|.|.} region we are in.
1117  const char *LastEmitted = AsmStr; // One past the last character emitted.
1118
1119  while (*LastEmitted) {
1120    switch (*LastEmitted) {
1121    default: {
1122      // Not a special case, emit the string section literally.
1123      const char *LiteralEnd = LastEmitted+1;
1124      while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' &&
1125             *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n')
1126        ++LiteralEnd;
1127      if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1128        O.write(LastEmitted, LiteralEnd-LastEmitted);
1129      LastEmitted = LiteralEnd;
1130      break;
1131    }
1132    case '\n':
1133      ++LastEmitted;   // Consume newline character.
1134      O << '\n';       // Indent code with newline.
1135      break;
1136    case '$': {
1137      ++LastEmitted;   // Consume '$' character.
1138      bool Done = true;
1139
1140      // Handle escapes.
1141      switch (*LastEmitted) {
1142      default: Done = false; break;
1143      case '$':     // $$ -> $
1144        if (CurVariant == -1 || CurVariant == AsmPrinterVariant)
1145          O << '$';
1146        ++LastEmitted;  // Consume second '$' character.
1147        break;
1148      case '(':             // $( -> same as GCC's { character.
1149        ++LastEmitted;      // Consume '(' character.
1150        if (CurVariant != -1) {
1151          llvm_report_error("Nested variants found in inline asm string: '"
1152                            + std::string(AsmStr) + "'");
1153        }
1154        CurVariant = 0;     // We're in the first variant now.
1155        break;
1156      case '|':
1157        ++LastEmitted;  // consume '|' character.
1158        if (CurVariant == -1)
1159          O << '|';       // this is gcc's behavior for | outside a variant
1160        else
1161          ++CurVariant;   // We're in the next variant.
1162        break;
1163      case ')':         // $) -> same as GCC's } char.
1164        ++LastEmitted;  // consume ')' character.
1165        if (CurVariant == -1)
1166          O << '}';     // this is gcc's behavior for } outside a variant
1167        else
1168          CurVariant = -1;
1169        break;
1170      }
1171      if (Done) break;
1172
1173      bool HasCurlyBraces = false;
1174      if (*LastEmitted == '{') {     // ${variable}
1175        ++LastEmitted;               // Consume '{' character.
1176        HasCurlyBraces = true;
1177      }
1178
1179      // If we have ${:foo}, then this is not a real operand reference, it is a
1180      // "magic" string reference, just like in .td files.  Arrange to call
1181      // PrintSpecial.
1182      if (HasCurlyBraces && *LastEmitted == ':') {
1183        ++LastEmitted;
1184        const char *StrStart = LastEmitted;
1185        const char *StrEnd = strchr(StrStart, '}');
1186        if (StrEnd == 0) {
1187          llvm_report_error("Unterminated ${:foo} operand in inline asm string: '"
1188                            + std::string(AsmStr) + "'");
1189        }
1190
1191        std::string Val(StrStart, StrEnd);
1192        PrintSpecial(MI, Val.c_str());
1193        LastEmitted = StrEnd+1;
1194        break;
1195      }
1196
1197      const char *IDStart = LastEmitted;
1198      char *IDEnd;
1199      errno = 0;
1200      long Val = strtol(IDStart, &IDEnd, 10); // We only accept numbers for IDs.
1201      if (!isdigit(*IDStart) || (Val == 0 && errno == EINVAL)) {
1202        llvm_report_error("Bad $ operand number in inline asm string: '"
1203                          + std::string(AsmStr) + "'");
1204      }
1205      LastEmitted = IDEnd;
1206
1207      char Modifier[2] = { 0, 0 };
1208
1209      if (HasCurlyBraces) {
1210        // If we have curly braces, check for a modifier character.  This
1211        // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm.
1212        if (*LastEmitted == ':') {
1213          ++LastEmitted;    // Consume ':' character.
1214          if (*LastEmitted == 0) {
1215            llvm_report_error("Bad ${:} expression in inline asm string: '"
1216                              + std::string(AsmStr) + "'");
1217          }
1218
1219          Modifier[0] = *LastEmitted;
1220          ++LastEmitted;    // Consume modifier character.
1221        }
1222
1223        if (*LastEmitted != '}') {
1224          llvm_report_error("Bad ${} expression in inline asm string: '"
1225                            + std::string(AsmStr) + "'");
1226        }
1227        ++LastEmitted;    // Consume '}' character.
1228      }
1229
1230      if ((unsigned)Val >= NumOperands-1) {
1231        llvm_report_error("Invalid $ operand number in inline asm string: '"
1232                          + std::string(AsmStr) + "'");
1233      }
1234
1235      // Okay, we finally have a value number.  Ask the target to print this
1236      // operand!
1237      if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {
1238        unsigned OpNo = 1;
1239
1240        bool Error = false;
1241
1242        // Scan to find the machine operand number for the operand.
1243        for (; Val; --Val) {
1244          if (OpNo >= MI->getNumOperands()) break;
1245          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1246          OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1;
1247        }
1248
1249        if (OpNo >= MI->getNumOperands()) {
1250          Error = true;
1251        } else {
1252          unsigned OpFlags = MI->getOperand(OpNo).getImm();
1253          ++OpNo;  // Skip over the ID number.
1254
1255          if (Modifier[0] == 'l')  // labels are target independent
1256            O << *GetMBBSymbol(MI->getOperand(OpNo).getMBB()->getNumber());
1257          else {
1258            AsmPrinter *AP = const_cast<AsmPrinter*>(this);
1259            if ((OpFlags & 7) == 4) {
1260              Error = AP->PrintAsmMemoryOperand(MI, OpNo, AsmPrinterVariant,
1261                                                Modifier[0] ? Modifier : 0);
1262            } else {
1263              Error = AP->PrintAsmOperand(MI, OpNo, AsmPrinterVariant,
1264                                          Modifier[0] ? Modifier : 0);
1265            }
1266          }
1267        }
1268        if (Error) {
1269          std::string msg;
1270          raw_string_ostream Msg(msg);
1271          Msg << "Invalid operand found in inline asm: '" << AsmStr << "'\n";
1272          MI->print(Msg);
1273          llvm_report_error(Msg.str());
1274        }
1275      }
1276      break;
1277    }
1278    }
1279  }
1280  O << "\n\t" << MAI->getCommentString() << MAI->getInlineAsmEnd();
1281}
1282
1283/// printImplicitDef - This method prints the specified machine instruction
1284/// that is an implicit def.
1285void AsmPrinter::printImplicitDef(const MachineInstr *MI) const {
1286  if (!VerboseAsm) return;
1287  O.PadToColumn(MAI->getCommentColumn());
1288  O << MAI->getCommentString() << " implicit-def: "
1289    << TRI->getName(MI->getOperand(0).getReg());
1290}
1291
1292void AsmPrinter::printKill(const MachineInstr *MI) const {
1293  if (!VerboseAsm) return;
1294  O.PadToColumn(MAI->getCommentColumn());
1295  O << MAI->getCommentString() << " kill:";
1296  for (unsigned n = 0, e = MI->getNumOperands(); n != e; ++n) {
1297    const MachineOperand &op = MI->getOperand(n);
1298    assert(op.isReg() && "KILL instruction must have only register operands");
1299    O << ' ' << TRI->getName(op.getReg()) << (op.isDef() ? "<def>" : "<kill>");
1300  }
1301}
1302
1303/// printLabel - This method prints a local label used by debug and
1304/// exception handling tables.
1305void AsmPrinter::printLabel(const MachineInstr *MI) const {
1306  printLabel(MI->getOperand(0).getImm());
1307}
1308
1309void AsmPrinter::printLabel(unsigned Id) const {
1310  O << MAI->getPrivateGlobalPrefix() << "label" << Id << ':';
1311}
1312
1313/// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
1314/// instruction, using the specified assembler variant.  Targets should
1315/// override this to format as appropriate.
1316bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
1317                                 unsigned AsmVariant, const char *ExtraCode) {
1318  // Target doesn't support this yet!
1319  return true;
1320}
1321
1322bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
1323                                       unsigned AsmVariant,
1324                                       const char *ExtraCode) {
1325  // Target doesn't support this yet!
1326  return true;
1327}
1328
1329MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA,
1330                                            const char *Suffix) const {
1331  return GetBlockAddressSymbol(BA->getFunction(), BA->getBasicBlock(), Suffix);
1332}
1333
1334MCSymbol *AsmPrinter::GetBlockAddressSymbol(const Function *F,
1335                                            const BasicBlock *BB,
1336                                            const char *Suffix) const {
1337  assert(BB->hasName() &&
1338         "Address of anonymous basic block not supported yet!");
1339
1340  // This code must use the function name itself, and not the function number,
1341  // since it must be possible to generate the label name from within other
1342  // functions.
1343  SmallString<60> FnName;
1344  Mang->getNameWithPrefix(FnName, F, false);
1345
1346  // FIXME: THIS IS BROKEN IF THE LLVM BASIC BLOCK DOESN'T HAVE A NAME!
1347  SmallString<60> NameResult;
1348  Mang->getNameWithPrefix(NameResult,
1349                          StringRef("BA") + Twine((unsigned)FnName.size()) +
1350                          "_" + FnName.str() + "_" + BB->getName() + Suffix,
1351                          Mangler::Private);
1352
1353  return OutContext.GetOrCreateSymbol(NameResult.str());
1354}
1355
1356MCSymbol *AsmPrinter::GetMBBSymbol(unsigned MBBID) const {
1357  SmallString<60> Name;
1358  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix() << "BB"
1359    << getFunctionNumber() << '_' << MBBID;
1360  return OutContext.GetOrCreateSymbol(Name.str());
1361}
1362
1363/// GetCPISymbol - Return the symbol for the specified constant pool entry.
1364MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
1365  SmallString<60> Name;
1366  raw_svector_ostream(Name) << MAI->getPrivateGlobalPrefix() << "CPI"
1367    << getFunctionNumber() << '_' << CPID;
1368  return OutContext.GetOrCreateSymbol(Name.str());
1369}
1370
1371/// GetJTISymbol - Return the symbol for the specified jump table entry.
1372MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
1373  const char *Prefix = isLinkerPrivate ? MAI->getLinkerPrivateGlobalPrefix() :
1374                                         MAI->getPrivateGlobalPrefix();
1375  SmallString<60> Name;
1376  raw_svector_ostream(Name) << Prefix << "JTI" << getFunctionNumber() << '_'
1377    << JTID;
1378  return OutContext.GetOrCreateSymbol(Name.str());
1379}
1380
1381/// GetGlobalValueSymbol - Return the MCSymbol for the specified global
1382/// value.
1383MCSymbol *AsmPrinter::GetGlobalValueSymbol(const GlobalValue *GV) const {
1384  SmallString<60> NameStr;
1385  Mang->getNameWithPrefix(NameStr, GV, false);
1386  return OutContext.GetOrCreateSymbol(NameStr.str());
1387}
1388
1389/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
1390/// global value name as its base, with the specified suffix, and where the
1391/// symbol is forced to have private linkage if ForcePrivate is true.
1392MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
1393                                                   StringRef Suffix,
1394                                                   bool ForcePrivate) const {
1395  SmallString<60> NameStr;
1396  Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
1397  NameStr.append(Suffix.begin(), Suffix.end());
1398  return OutContext.GetOrCreateSymbol(NameStr.str());
1399}
1400
1401/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
1402/// ExternalSymbol.
1403MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
1404  SmallString<60> NameStr;
1405  Mang->getNameWithPrefix(NameStr, Sym);
1406  return OutContext.GetOrCreateSymbol(NameStr.str());
1407}
1408
1409
1410
1411/// PrintParentLoopComment - Print comments about parent loops of this one.
1412static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1413                                   unsigned FunctionNumber) {
1414  if (Loop == 0) return;
1415  PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
1416  OS.indent(Loop->getLoopDepth()*2)
1417    << "Parent Loop BB" << FunctionNumber << "_"
1418    << Loop->getHeader()->getNumber()
1419    << " Depth=" << Loop->getLoopDepth() << '\n';
1420}
1421
1422
1423/// PrintChildLoopComment - Print comments about child loops within
1424/// the loop for this basic block, with nesting.
1425static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
1426                                  unsigned FunctionNumber) {
1427  // Add child loop information
1428  for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
1429    OS.indent((*CL)->getLoopDepth()*2)
1430      << "Child Loop BB" << FunctionNumber << "_"
1431      << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
1432      << '\n';
1433    PrintChildLoopComment(OS, *CL, FunctionNumber);
1434  }
1435}
1436
1437/// EmitComments - Pretty-print comments for basic blocks.
1438static void PrintBasicBlockLoopComments(const MachineBasicBlock &MBB,
1439                                        const MachineLoopInfo *LI,
1440                                        const AsmPrinter &AP) {
1441  // Add loop depth information
1442  const MachineLoop *Loop = LI->getLoopFor(&MBB);
1443  if (Loop == 0) return;
1444
1445  MachineBasicBlock *Header = Loop->getHeader();
1446  assert(Header && "No header for loop");
1447
1448  // If this block is not a loop header, just print out what is the loop header
1449  // and return.
1450  if (Header != &MBB) {
1451    AP.OutStreamer.AddComment("  in Loop: Header=BB" +
1452                              Twine(AP.getFunctionNumber())+"_" +
1453                              Twine(Loop->getHeader()->getNumber())+
1454                              " Depth="+Twine(Loop->getLoopDepth()));
1455    return;
1456  }
1457
1458  // Otherwise, it is a loop header.  Print out information about child and
1459  // parent loops.
1460  raw_ostream &OS = AP.OutStreamer.GetCommentOS();
1461
1462  PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
1463
1464  OS << "=>";
1465  OS.indent(Loop->getLoopDepth()*2-2);
1466
1467  OS << "This ";
1468  if (Loop->empty())
1469    OS << "Inner ";
1470  OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
1471
1472  PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
1473}
1474
1475
1476/// EmitBasicBlockStart - This method prints the label for the specified
1477/// MachineBasicBlock, an alignment (if present) and a comment describing
1478/// it if appropriate.
1479void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
1480  // Emit an alignment directive for this block, if needed.
1481  if (unsigned Align = MBB->getAlignment())
1482    EmitAlignment(Log2_32(Align));
1483
1484  // If the block has its address taken, emit a special label to satisfy
1485  // references to the block. This is done so that we don't need to
1486  // remember the number of this label, and so that we can make
1487  // forward references to labels without knowing what their numbers
1488  // will be.
1489  if (MBB->hasAddressTaken()) {
1490    const BasicBlock *BB = MBB->getBasicBlock();
1491    if (VerboseAsm)
1492      OutStreamer.AddComment("Address Taken");
1493    OutStreamer.EmitLabel(GetBlockAddressSymbol(BB->getParent(), BB));
1494  }
1495
1496  // Print the main label for the block.
1497  if (MBB->pred_empty() || MBB->isOnlyReachableByFallthrough()) {
1498    if (VerboseAsm) {
1499      // NOTE: Want this comment at start of line.
1500      O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
1501      if (const BasicBlock *BB = MBB->getBasicBlock())
1502        if (BB->hasName())
1503          OutStreamer.AddComment("%" + BB->getName());
1504
1505      PrintBasicBlockLoopComments(*MBB, LI, *this);
1506      OutStreamer.AddBlankLine();
1507    }
1508  } else {
1509    if (VerboseAsm) {
1510      if (const BasicBlock *BB = MBB->getBasicBlock())
1511        if (BB->hasName())
1512          OutStreamer.AddComment("%" + BB->getName());
1513      PrintBasicBlockLoopComments(*MBB, LI, *this);
1514    }
1515
1516    OutStreamer.EmitLabel(GetMBBSymbol(MBB->getNumber()));
1517  }
1518}
1519
1520/// printPICJumpTableSetLabel - This method prints a set label for the
1521/// specified MachineBasicBlock for a jumptable entry.
1522void AsmPrinter::printPICJumpTableSetLabel(unsigned uid,
1523                                           const MachineBasicBlock *MBB) const {
1524  if (!MAI->getSetDirective())
1525    return;
1526
1527  O << MAI->getSetDirective() << ' ' << MAI->getPrivateGlobalPrefix()
1528    << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ','
1529    << *GetMBBSymbol(MBB->getNumber())
1530    << '-' << *GetJTISymbol(uid) << '\n';
1531}
1532
1533void AsmPrinter::printVisibility(MCSymbol *Sym, unsigned Visibility) const {
1534  MCSymbolAttr Attr = MCSA_Invalid;
1535
1536  switch (Visibility) {
1537  default: break;
1538  case GlobalValue::HiddenVisibility:
1539    Attr = MAI->getHiddenVisibilityAttr();
1540    break;
1541  case GlobalValue::ProtectedVisibility:
1542    Attr = MAI->getProtectedVisibilityAttr();
1543    break;
1544  }
1545
1546  if (Attr != MCSA_Invalid)
1547    OutStreamer.EmitSymbolAttribute(Sym, Attr);
1548}
1549
1550void AsmPrinter::printOffset(int64_t Offset) const {
1551  if (Offset > 0)
1552    O << '+' << Offset;
1553  else if (Offset < 0)
1554    O << Offset;
1555}
1556
1557GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
1558  if (!S->usesMetadata())
1559    return 0;
1560
1561  gcp_iterator GCPI = GCMetadataPrinters.find(S);
1562  if (GCPI != GCMetadataPrinters.end())
1563    return GCPI->second;
1564
1565  const char *Name = S->getName().c_str();
1566
1567  for (GCMetadataPrinterRegistry::iterator
1568         I = GCMetadataPrinterRegistry::begin(),
1569         E = GCMetadataPrinterRegistry::end(); I != E; ++I)
1570    if (strcmp(Name, I->getName()) == 0) {
1571      GCMetadataPrinter *GMP = I->instantiate();
1572      GMP->S = S;
1573      GCMetadataPrinters.insert(std::make_pair(S, GMP));
1574      return GMP;
1575    }
1576
1577  llvm_report_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
1578  return 0;
1579}
1580
1581/// EmitComments - Pretty-print comments for instructions
1582void AsmPrinter::EmitComments(const MachineInstr &MI) const {
1583  if (!VerboseAsm)
1584    return;
1585
1586  bool Newline = false;
1587
1588  if (!MI.getDebugLoc().isUnknown()) {
1589    DILocation DLT = MF->getDILocation(MI.getDebugLoc());
1590
1591    // Print source line info.
1592    O.PadToColumn(MAI->getCommentColumn());
1593    O << MAI->getCommentString() << ' ';
1594    DIScope Scope = DLT.getScope();
1595    // Omit the directory, because it's likely to be long and uninteresting.
1596    if (!Scope.isNull())
1597      O << Scope.getFilename();
1598    else
1599      O << "<unknown>";
1600    O << ':' << DLT.getLineNumber();
1601    if (DLT.getColumnNumber() != 0)
1602      O << ':' << DLT.getColumnNumber();
1603    Newline = true;
1604  }
1605
1606  // Check for spills and reloads
1607  int FI;
1608
1609  const MachineFrameInfo *FrameInfo =
1610    MI.getParent()->getParent()->getFrameInfo();
1611
1612  // We assume a single instruction only has a spill or reload, not
1613  // both.
1614  const MachineMemOperand *MMO;
1615  if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
1616    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
1617      MMO = *MI.memoperands_begin();
1618      if (Newline) O << '\n';
1619      O.PadToColumn(MAI->getCommentColumn());
1620      O << MAI->getCommentString() << ' ' << MMO->getSize() << "-byte Reload";
1621      Newline = true;
1622    }
1623  }
1624  else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
1625    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
1626      if (Newline) O << '\n';
1627      O.PadToColumn(MAI->getCommentColumn());
1628      O << MAI->getCommentString() << ' '
1629        << MMO->getSize() << "-byte Folded Reload";
1630      Newline = true;
1631    }
1632  }
1633  else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
1634    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
1635      MMO = *MI.memoperands_begin();
1636      if (Newline) O << '\n';
1637      O.PadToColumn(MAI->getCommentColumn());
1638      O << MAI->getCommentString() << ' ' << MMO->getSize() << "-byte Spill";
1639      Newline = true;
1640    }
1641  }
1642  else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
1643    if (FrameInfo->isSpillSlotObjectIndex(FI)) {
1644      if (Newline) O << '\n';
1645      O.PadToColumn(MAI->getCommentColumn());
1646      O << MAI->getCommentString() << ' '
1647        << MMO->getSize() << "-byte Folded Spill";
1648      Newline = true;
1649    }
1650  }
1651
1652  // Check for spill-induced copies
1653  unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
1654  if (TM.getInstrInfo()->isMoveInstr(MI, SrcReg, DstReg,
1655                                      SrcSubIdx, DstSubIdx)) {
1656    if (MI.getAsmPrinterFlag(ReloadReuse)) {
1657      if (Newline) O << '\n';
1658      O.PadToColumn(MAI->getCommentColumn());
1659      O << MAI->getCommentString() << " Reload Reuse";
1660    }
1661  }
1662}
1663
1664