X86AsmPrinter.cpp revision b74b88edac9ab490ba428aef0bdebc957399bbd7 
1//===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
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 contains a printer that converts from our internal representation
11// of machine-dependent LLVM code to X86 machine code.
12//
13//===----------------------------------------------------------------------===//
14
15#include "X86AsmPrinter.h"
16#include "InstPrinter/X86ATTInstPrinter.h"
17#include "X86.h"
18#include "X86COFFMachineModuleInfo.h"
19#include "X86MachineFunctionInfo.h"
20#include "X86TargetMachine.h"
21#include "llvm/ADT/SmallString.h"
22#include "llvm/Assembly/Writer.h"
23#include "llvm/CodeGen/MachineJumpTableInfo.h"
24#include "llvm/CodeGen/MachineModuleInfoImpls.h"
25#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
26#include "llvm/DebugInfo.h"
27#include "llvm/IR/CallingConv.h"
28#include "llvm/IR/DerivedTypes.h"
29#include "llvm/IR/Module.h"
30#include "llvm/IR/Type.h"
31#include "llvm/MC/MCAsmInfo.h"
32#include "llvm/MC/MCContext.h"
33#include "llvm/MC/MCExpr.h"
34#include "llvm/MC/MCSectionMachO.h"
35#include "llvm/MC/MCStreamer.h"
36#include "llvm/MC/MCSymbol.h"
37#include "llvm/Support/COFF.h"
38#include "llvm/Support/Debug.h"
39#include "llvm/Support/ErrorHandling.h"
40#include "llvm/Support/TargetRegistry.h"
41#include "llvm/Target/Mangler.h"
42#include "llvm/Target/TargetOptions.h"
43using namespace llvm;
44
45//===----------------------------------------------------------------------===//
46// Primitive Helper Functions.
47//===----------------------------------------------------------------------===//
48
49/// runOnMachineFunction - Emit the function body.
50///
51bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
52  SetupMachineFunction(MF);
53
54  if (Subtarget->isTargetCOFF() && !Subtarget->isTargetEnvMacho()) {
55    bool Intrn = MF.getFunction()->hasInternalLinkage();
56    OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
57    OutStreamer.EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
58                                              : COFF::IMAGE_SYM_CLASS_EXTERNAL);
59    OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
60                                               << COFF::SCT_COMPLEX_TYPE_SHIFT);
61    OutStreamer.EndCOFFSymbolDef();
62  }
63
64  // Have common code print out the function header with linkage info etc.
65  EmitFunctionHeader();
66
67  // Emit the rest of the function body.
68  EmitFunctionBody();
69
70  // We didn't modify anything.
71  return false;
72}
73
74/// printSymbolOperand - Print a raw symbol reference operand.  This handles
75/// jump tables, constant pools, global address and external symbols, all of
76/// which print to a label with various suffixes for relocation types etc.
77void X86AsmPrinter::printSymbolOperand(const MachineOperand &MO,
78                                       raw_ostream &O) {
79  switch (MO.getType()) {
80  default: llvm_unreachable("unknown symbol type!");
81  case MachineOperand::MO_JumpTableIndex:
82    O << *GetJTISymbol(MO.getIndex());
83    break;
84  case MachineOperand::MO_ConstantPoolIndex:
85    O << *GetCPISymbol(MO.getIndex());
86    printOffset(MO.getOffset(), O);
87    break;
88  case MachineOperand::MO_GlobalAddress: {
89    const GlobalValue *GV = MO.getGlobal();
90
91    MCSymbol *GVSym;
92    if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
93      GVSym = GetSymbolWithGlobalValueBase(GV, "$stub");
94    else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
95             MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
96             MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
97      GVSym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
98    else
99      GVSym = Mang->getSymbol(GV);
100
101    // Handle dllimport linkage.
102    if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
103      GVSym = OutContext.GetOrCreateSymbol(Twine("__imp_") + GVSym->getName());
104
105    if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
106        MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
107      MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
108      MachineModuleInfoImpl::StubValueTy &StubSym =
109        MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
110      if (StubSym.getPointer() == 0)
111        StubSym = MachineModuleInfoImpl::
112          StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
113    } else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
114      MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
115      MachineModuleInfoImpl::StubValueTy &StubSym =
116        MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(Sym);
117      if (StubSym.getPointer() == 0)
118        StubSym = MachineModuleInfoImpl::
119          StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
120    } else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
121      MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$stub");
122      MachineModuleInfoImpl::StubValueTy &StubSym =
123        MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
124      if (StubSym.getPointer() == 0)
125        StubSym = MachineModuleInfoImpl::
126          StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
127    }
128
129    // If the name begins with a dollar-sign, enclose it in parens.  We do this
130    // to avoid having it look like an integer immediate to the assembler.
131    if (GVSym->getName()[0] != '$')
132      O << *GVSym;
133    else
134      O << '(' << *GVSym << ')';
135    printOffset(MO.getOffset(), O);
136    break;
137  }
138  case MachineOperand::MO_ExternalSymbol: {
139    const MCSymbol *SymToPrint;
140    if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
141      SmallString<128> TempNameStr;
142      TempNameStr += StringRef(MO.getSymbolName());
143      TempNameStr += StringRef("$stub");
144
145      MCSymbol *Sym = GetExternalSymbolSymbol(TempNameStr.str());
146      MachineModuleInfoImpl::StubValueTy &StubSym =
147        MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
148      if (StubSym.getPointer() == 0) {
149        TempNameStr.erase(TempNameStr.end()-5, TempNameStr.end());
150        StubSym = MachineModuleInfoImpl::
151          StubValueTy(OutContext.GetOrCreateSymbol(TempNameStr.str()),
152                      true);
153      }
154      SymToPrint = StubSym.getPointer();
155    } else {
156      SymToPrint = GetExternalSymbolSymbol(MO.getSymbolName());
157    }
158
159    // If the name begins with a dollar-sign, enclose it in parens.  We do this
160    // to avoid having it look like an integer immediate to the assembler.
161    if (SymToPrint->getName()[0] != '$')
162      O << *SymToPrint;
163    else
164      O << '(' << *SymToPrint << '(';
165    break;
166  }
167  }
168
169  switch (MO.getTargetFlags()) {
170  default:
171    llvm_unreachable("Unknown target flag on GV operand");
172  case X86II::MO_NO_FLAG:    // No flag.
173    break;
174  case X86II::MO_DARWIN_NONLAZY:
175  case X86II::MO_DLLIMPORT:
176  case X86II::MO_DARWIN_STUB:
177    // These affect the name of the symbol, not any suffix.
178    break;
179  case X86II::MO_GOT_ABSOLUTE_ADDRESS:
180    O << " + [.-" << *MF->getPICBaseSymbol() << ']';
181    break;
182  case X86II::MO_PIC_BASE_OFFSET:
183  case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
184  case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
185    O << '-' << *MF->getPICBaseSymbol();
186    break;
187  case X86II::MO_TLSGD:     O << "@TLSGD";     break;
188  case X86II::MO_TLSLD:     O << "@TLSLD";     break;
189  case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
190  case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
191  case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
192  case X86II::MO_TPOFF:     O << "@TPOFF";     break;
193  case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
194  case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
195  case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
196  case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
197  case X86II::MO_GOT:       O << "@GOT";       break;
198  case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
199  case X86II::MO_PLT:       O << "@PLT";       break;
200  case X86II::MO_TLVP:      O << "@TLVP";      break;
201  case X86II::MO_TLVP_PIC_BASE:
202    O << "@TLVP" << '-' << *MF->getPICBaseSymbol();
203    break;
204  case X86II::MO_SECREL:    O << "@SECREL32";  break;
205  }
206}
207
208/// printPCRelImm - This is used to print an immediate value that ends up
209/// being encoded as a pc-relative value.  These print slightly differently, for
210/// example, a $ is not emitted.
211void X86AsmPrinter::printPCRelImm(const MachineInstr *MI, unsigned OpNo,
212                                    raw_ostream &O) {
213  const MachineOperand &MO = MI->getOperand(OpNo);
214  switch (MO.getType()) {
215  default: llvm_unreachable("Unknown pcrel immediate operand");
216  case MachineOperand::MO_Register:
217    // pc-relativeness was handled when computing the value in the reg.
218    printOperand(MI, OpNo, O);
219    return;
220  case MachineOperand::MO_Immediate:
221    O << MO.getImm();
222    return;
223  case MachineOperand::MO_MachineBasicBlock:
224    O << *MO.getMBB()->getSymbol();
225    return;
226  case MachineOperand::MO_GlobalAddress:
227  case MachineOperand::MO_ExternalSymbol:
228    printSymbolOperand(MO, O);
229    return;
230  }
231}
232
233
234void X86AsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
235                                 raw_ostream &O, const char *Modifier,
236                                 unsigned AsmVariant) {
237  const MachineOperand &MO = MI->getOperand(OpNo);
238  switch (MO.getType()) {
239  default: llvm_unreachable("unknown operand type!");
240  case MachineOperand::MO_Register: {
241    // FIXME: Enumerating AsmVariant, so we can remove magic number.
242    if (AsmVariant == 0) O << '%';
243    unsigned Reg = MO.getReg();
244    if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
245      MVT::SimpleValueType VT = (strcmp(Modifier+6,"64") == 0) ?
246        MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
247                    ((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
248      Reg = getX86SubSuperRegister(Reg, VT);
249    }
250    O << X86ATTInstPrinter::getRegisterName(Reg);
251    return;
252  }
253
254  case MachineOperand::MO_Immediate:
255    if (AsmVariant == 0) O << '$';
256    O << MO.getImm();
257    return;
258
259  case MachineOperand::MO_JumpTableIndex:
260  case MachineOperand::MO_ConstantPoolIndex:
261  case MachineOperand::MO_GlobalAddress:
262  case MachineOperand::MO_ExternalSymbol: {
263    if (AsmVariant == 0) O << '$';
264    printSymbolOperand(MO, O);
265    break;
266  }
267  }
268}
269
270void X86AsmPrinter::printLeaMemReference(const MachineInstr *MI, unsigned Op,
271                                         raw_ostream &O, const char *Modifier) {
272  const MachineOperand &BaseReg  = MI->getOperand(Op);
273  const MachineOperand &IndexReg = MI->getOperand(Op+2);
274  const MachineOperand &DispSpec = MI->getOperand(Op+3);
275
276  // If we really don't want to print out (rip), don't.
277  bool HasBaseReg = BaseReg.getReg() != 0;
278  if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
279      BaseReg.getReg() == X86::RIP)
280    HasBaseReg = false;
281
282  // HasParenPart - True if we will print out the () part of the mem ref.
283  bool HasParenPart = IndexReg.getReg() || HasBaseReg;
284
285  if (DispSpec.isImm()) {
286    int DispVal = DispSpec.getImm();
287    if (DispVal || !HasParenPart)
288      O << DispVal;
289  } else {
290    assert(DispSpec.isGlobal() || DispSpec.isCPI() ||
291           DispSpec.isJTI() || DispSpec.isSymbol());
292    printSymbolOperand(MI->getOperand(Op+3), O);
293  }
294
295  if (Modifier && strcmp(Modifier, "H") == 0)
296    O << "+8";
297
298  if (HasParenPart) {
299    assert(IndexReg.getReg() != X86::ESP &&
300           "X86 doesn't allow scaling by ESP");
301
302    O << '(';
303    if (HasBaseReg)
304      printOperand(MI, Op, O, Modifier);
305
306    if (IndexReg.getReg()) {
307      O << ',';
308      printOperand(MI, Op+2, O, Modifier);
309      unsigned ScaleVal = MI->getOperand(Op+1).getImm();
310      if (ScaleVal != 1)
311        O << ',' << ScaleVal;
312    }
313    O << ')';
314  }
315}
316
317void X86AsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
318                                      raw_ostream &O, const char *Modifier) {
319  assert(isMem(MI, Op) && "Invalid memory reference!");
320  const MachineOperand &Segment = MI->getOperand(Op+4);
321  if (Segment.getReg()) {
322    printOperand(MI, Op+4, O, Modifier);
323    O << ':';
324  }
325  printLeaMemReference(MI, Op, O, Modifier);
326}
327
328void X86AsmPrinter::printIntelMemReference(const MachineInstr *MI, unsigned Op,
329                                           raw_ostream &O, const char *Modifier,
330                                           unsigned AsmVariant){
331  const MachineOperand &BaseReg  = MI->getOperand(Op);
332  unsigned ScaleVal = MI->getOperand(Op+1).getImm();
333  const MachineOperand &IndexReg = MI->getOperand(Op+2);
334  const MachineOperand &DispSpec = MI->getOperand(Op+3);
335  const MachineOperand &SegReg   = MI->getOperand(Op+4);
336
337  // If this has a segment register, print it.
338  if (SegReg.getReg()) {
339    printOperand(MI, Op+4, O, Modifier, AsmVariant);
340    O << ':';
341  }
342
343  O << '[';
344
345  bool NeedPlus = false;
346  if (BaseReg.getReg()) {
347    printOperand(MI, Op, O, Modifier, AsmVariant);
348    NeedPlus = true;
349  }
350
351  if (IndexReg.getReg()) {
352    if (NeedPlus) O << " + ";
353    if (ScaleVal != 1)
354      O << ScaleVal << '*';
355    printOperand(MI, Op+2, O, Modifier, AsmVariant);
356    NeedPlus = true;
357  }
358
359  if (!DispSpec.isImm()) {
360    if (NeedPlus) O << " + ";
361    printOperand(MI, Op+3, O, Modifier, AsmVariant);
362  } else {
363    int64_t DispVal = DispSpec.getImm();
364    if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
365      if (NeedPlus) {
366        if (DispVal > 0)
367          O << " + ";
368        else {
369          O << " - ";
370          DispVal = -DispVal;
371        }
372      }
373      O << DispVal;
374    }
375  }
376  O << ']';
377}
378
379bool X86AsmPrinter::printAsmMRegister(const MachineOperand &MO, char Mode,
380                                      raw_ostream &O) {
381  unsigned Reg = MO.getReg();
382  switch (Mode) {
383  default: return true;  // Unknown mode.
384  case 'b': // Print QImode register
385    Reg = getX86SubSuperRegister(Reg, MVT::i8);
386    break;
387  case 'h': // Print QImode high register
388    Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
389    break;
390  case 'w': // Print HImode register
391    Reg = getX86SubSuperRegister(Reg, MVT::i16);
392    break;
393  case 'k': // Print SImode register
394    Reg = getX86SubSuperRegister(Reg, MVT::i32);
395    break;
396  case 'q': // Print DImode register
397    Reg = getX86SubSuperRegister(Reg, MVT::i64);
398    break;
399  }
400
401  O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
402  return false;
403}
404
405/// PrintAsmOperand - Print out an operand for an inline asm expression.
406///
407bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
408                                    unsigned AsmVariant,
409                                    const char *ExtraCode, raw_ostream &O) {
410  // Does this asm operand have a single letter operand modifier?
411  if (ExtraCode && ExtraCode[0]) {
412    if (ExtraCode[1] != 0) return true; // Unknown modifier.
413
414    const MachineOperand &MO = MI->getOperand(OpNo);
415
416    switch (ExtraCode[0]) {
417    default:
418      // See if this is a generic print operand
419      return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
420    case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
421      if (MO.isImm()) {
422        O << MO.getImm();
423        return false;
424      }
425      if (MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isSymbol()) {
426        printSymbolOperand(MO, O);
427        if (Subtarget->isPICStyleRIPRel())
428          O << "(%rip)";
429        return false;
430      }
431      if (MO.isReg()) {
432        O << '(';
433        printOperand(MI, OpNo, O);
434        O << ')';
435        return false;
436      }
437      return true;
438
439    case 'c': // Don't print "$" before a global var name or constant.
440      if (MO.isImm())
441        O << MO.getImm();
442      else if (MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isSymbol())
443        printSymbolOperand(MO, O);
444      else
445        printOperand(MI, OpNo, O);
446      return false;
447
448    case 'A': // Print '*' before a register (it must be a register)
449      if (MO.isReg()) {
450        O << '*';
451        printOperand(MI, OpNo, O);
452        return false;
453      }
454      return true;
455
456    case 'b': // Print QImode register
457    case 'h': // Print QImode high register
458    case 'w': // Print HImode register
459    case 'k': // Print SImode register
460    case 'q': // Print DImode register
461      if (MO.isReg())
462        return printAsmMRegister(MO, ExtraCode[0], O);
463      printOperand(MI, OpNo, O);
464      return false;
465
466    case 'P': // This is the operand of a call, treat specially.
467      printPCRelImm(MI, OpNo, O);
468      return false;
469
470    case 'n':  // Negate the immediate or print a '-' before the operand.
471      // Note: this is a temporary solution. It should be handled target
472      // independently as part of the 'MC' work.
473      if (MO.isImm()) {
474        O << -MO.getImm();
475        return false;
476      }
477      O << '-';
478    }
479  }
480
481  printOperand(MI, OpNo, O, /*Modifier*/ 0, AsmVariant);
482  return false;
483}
484
485bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
486                                          unsigned OpNo, unsigned AsmVariant,
487                                          const char *ExtraCode,
488                                          raw_ostream &O) {
489  if (AsmVariant) {
490    printIntelMemReference(MI, OpNo, O);
491    return false;
492  }
493
494  if (ExtraCode && ExtraCode[0]) {
495    if (ExtraCode[1] != 0) return true; // Unknown modifier.
496
497    switch (ExtraCode[0]) {
498    default: return true;  // Unknown modifier.
499    case 'b': // Print QImode register
500    case 'h': // Print QImode high register
501    case 'w': // Print HImode register
502    case 'k': // Print SImode register
503    case 'q': // Print SImode register
504      // These only apply to registers, ignore on mem.
505      break;
506    case 'H':
507      printMemReference(MI, OpNo, O, "H");
508      return false;
509    case 'P': // Don't print @PLT, but do print as memory.
510      printMemReference(MI, OpNo, O, "no-rip");
511      return false;
512    }
513  }
514  printMemReference(MI, OpNo, O);
515  return false;
516}
517
518void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
519  if (Subtarget->isTargetEnvMacho())
520    OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
521
522  if (Subtarget->isTargetCOFF() && Subtarget->isTargetWindows()) {
523    // Emit an absolute @feat.00 symbol.  This appears to be some kind of
524    // compiler features bitfield read by link.exe.
525    // We only do this on win32, since on cygwin etc. we use the GNU assembler,
526    // which doesn't handle this symbol.
527    if (!Subtarget->is64Bit()) {
528      MCSymbol *S = MMI->getContext().GetOrCreateSymbol(StringRef("@feat.00"));
529      OutStreamer.BeginCOFFSymbolDef(S);
530      OutStreamer.EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
531      OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
532      OutStreamer.EndCOFFSymbolDef();
533      // According to the PE-COFF spec, the LSB of this value marks the object
534      // for "registered SEH".  This means that all SEH handler entry points
535      // must be registered in .sxdata.  Use of any unregistered handlers will
536      // cause the process to terminate immediately.  LLVM does not know how to
537      // register any SEH handlers, so its object files should be safe.
538      S->setAbsolute();
539      OutStreamer.EmitAssignment(
540          S, MCConstantExpr::Create(int64_t(1), MMI->getContext()));
541    }
542  }
543}
544
545
546void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
547  if (Subtarget->isTargetEnvMacho()) {
548    // All darwin targets use mach-o.
549    MachineModuleInfoMachO &MMIMacho =
550      MMI->getObjFileInfo<MachineModuleInfoMachO>();
551
552    // Output stubs for dynamically-linked functions.
553    MachineModuleInfoMachO::SymbolListTy Stubs;
554
555    Stubs = MMIMacho.GetFnStubList();
556    if (!Stubs.empty()) {
557      const MCSection *TheSection =
558        OutContext.getMachOSection("__IMPORT", "__jump_table",
559                                   MCSectionMachO::S_SYMBOL_STUBS |
560                                   MCSectionMachO::S_ATTR_SELF_MODIFYING_CODE |
561                                   MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
562                                   5, SectionKind::getMetadata());
563      OutStreamer.SwitchSection(TheSection);
564
565      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
566        // L_foo$stub:
567        OutStreamer.EmitLabel(Stubs[i].first);
568        //   .indirect_symbol _foo
569        OutStreamer.EmitSymbolAttribute(Stubs[i].second.getPointer(),
570                                        MCSA_IndirectSymbol);
571        // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
572        const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
573        OutStreamer.EmitBytes(StringRef(HltInsts, 5));
574      }
575
576      Stubs.clear();
577      OutStreamer.AddBlankLine();
578    }
579
580    // Output stubs for external and common global variables.
581    Stubs = MMIMacho.GetGVStubList();
582    if (!Stubs.empty()) {
583      const MCSection *TheSection =
584        OutContext.getMachOSection("__IMPORT", "__pointers",
585                                   MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
586                                   SectionKind::getMetadata());
587      OutStreamer.SwitchSection(TheSection);
588
589      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
590        // L_foo$non_lazy_ptr:
591        OutStreamer.EmitLabel(Stubs[i].first);
592        // .indirect_symbol _foo
593        MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
594        OutStreamer.EmitSymbolAttribute(MCSym.getPointer(),
595                                        MCSA_IndirectSymbol);
596        // .long 0
597        if (MCSym.getInt())
598          // External to current translation unit.
599          OutStreamer.EmitIntValue(0, 4/*size*/);
600        else
601          // Internal to current translation unit.
602          //
603          // When we place the LSDA into the TEXT section, the type info
604          // pointers need to be indirect and pc-rel. We accomplish this by
605          // using NLPs.  However, sometimes the types are local to the file. So
606          // we need to fill in the value for the NLP in those cases.
607          OutStreamer.EmitValue(MCSymbolRefExpr::Create(MCSym.getPointer(),
608                                                        OutContext), 4/*size*/);
609      }
610      Stubs.clear();
611      OutStreamer.AddBlankLine();
612    }
613
614    Stubs = MMIMacho.GetHiddenGVStubList();
615    if (!Stubs.empty()) {
616      OutStreamer.SwitchSection(getObjFileLowering().getDataSection());
617      EmitAlignment(2);
618
619      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
620        // L_foo$non_lazy_ptr:
621        OutStreamer.EmitLabel(Stubs[i].first);
622        // .long _foo
623        OutStreamer.EmitValue(MCSymbolRefExpr::
624                              Create(Stubs[i].second.getPointer(),
625                                     OutContext), 4/*size*/);
626      }
627      Stubs.clear();
628      OutStreamer.AddBlankLine();
629    }
630
631    // Funny Darwin hack: This flag tells the linker that no global symbols
632    // contain code that falls through to other global symbols (e.g. the obvious
633    // implementation of multiple entry points).  If this doesn't occur, the
634    // linker can safely perform dead code stripping.  Since LLVM never
635    // generates code that does this, it is always safe to set.
636    OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
637  }
638
639  if (Subtarget->isTargetWindows() && !Subtarget->isTargetCygMing() &&
640      MMI->usesVAFloatArgument()) {
641    StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
642    MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
643    OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
644  }
645
646  if (Subtarget->isTargetCOFF() && !Subtarget->isTargetEnvMacho()) {
647    X86COFFMachineModuleInfo &COFFMMI =
648      MMI->getObjFileInfo<X86COFFMachineModuleInfo>();
649
650    // Emit type information for external functions
651    typedef X86COFFMachineModuleInfo::externals_iterator externals_iterator;
652    for (externals_iterator I = COFFMMI.externals_begin(),
653                            E = COFFMMI.externals_end();
654                            I != E; ++I) {
655      OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
656      OutStreamer.EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
657      OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
658                                               << COFF::SCT_COMPLEX_TYPE_SHIFT);
659      OutStreamer.EndCOFFSymbolDef();
660    }
661
662    // Necessary for dllexport support
663    std::vector<const MCSymbol*> DLLExportedFns, DLLExportedGlobals;
664
665    const TargetLoweringObjectFileCOFF &TLOFCOFF =
666      static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
667
668    for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I)
669      if (I->hasDLLExportLinkage())
670        DLLExportedFns.push_back(Mang->getSymbol(I));
671
672    for (Module::const_global_iterator I = M.global_begin(),
673           E = M.global_end(); I != E; ++I)
674      if (I->hasDLLExportLinkage())
675        DLLExportedGlobals.push_back(Mang->getSymbol(I));
676
677    // Output linker support code for dllexported globals on windows.
678    if (!DLLExportedGlobals.empty() || !DLLExportedFns.empty()) {
679      OutStreamer.SwitchSection(TLOFCOFF.getDrectveSection());
680      SmallString<128> name;
681      for (unsigned i = 0, e = DLLExportedGlobals.size(); i != e; ++i) {
682        if (Subtarget->isTargetWindows())
683          name = " /EXPORT:";
684        else
685          name = " -export:";
686        name += DLLExportedGlobals[i]->getName();
687        if (Subtarget->isTargetWindows())
688          name += ",DATA";
689        else
690        name += ",data";
691        OutStreamer.EmitBytes(name);
692      }
693
694      for (unsigned i = 0, e = DLLExportedFns.size(); i != e; ++i) {
695        if (Subtarget->isTargetWindows())
696          name = " /EXPORT:";
697        else
698          name = " -export:";
699        name += DLLExportedFns[i]->getName();
700        OutStreamer.EmitBytes(name);
701      }
702    }
703  }
704
705  if (Subtarget->isTargetELF()) {
706    const TargetLoweringObjectFileELF &TLOFELF =
707      static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());
708
709    MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
710
711    // Output stubs for external and common global variables.
712    MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
713    if (!Stubs.empty()) {
714      OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
715      const DataLayout *TD = TM.getDataLayout();
716
717      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
718        OutStreamer.EmitLabel(Stubs[i].first);
719        OutStreamer.EmitSymbolValue(Stubs[i].second.getPointer(),
720                                    TD->getPointerSize());
721      }
722      Stubs.clear();
723    }
724  }
725}
726
727//===----------------------------------------------------------------------===//
728// Target Registry Stuff
729//===----------------------------------------------------------------------===//
730
731// Force static initialization.
732extern "C" void LLVMInitializeX86AsmPrinter() {
733  RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
734  RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
735}
736