BitcodeWriter.cpp revision 0a9f7b9c3ebe7d0ec033462e1a7c9101279956f9 
1//===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
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// Bitcode writer implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Bitcode/ReaderWriter.h"
15#include "llvm/Bitcode/BitstreamWriter.h"
16#include "llvm/Bitcode/LLVMBitCodes.h"
17#include "ValueEnumerator.h"
18#include "llvm/Constants.h"
19#include "llvm/DerivedTypes.h"
20#include "llvm/InlineAsm.h"
21#include "llvm/Instructions.h"
22#include "llvm/Metadata.h"
23#include "llvm/Module.h"
24#include "llvm/Operator.h"
25#include "llvm/TypeSymbolTable.h"
26#include "llvm/ValueSymbolTable.h"
27#include "llvm/Support/ErrorHandling.h"
28#include "llvm/Support/MathExtras.h"
29#include "llvm/Support/Streams.h"
30#include "llvm/Support/raw_ostream.h"
31#include "llvm/System/Program.h"
32using namespace llvm;
33
34/// These are manifest constants used by the bitcode writer. They do not need to
35/// be kept in sync with the reader, but need to be consistent within this file.
36enum {
37  CurVersion = 0,
38
39  // VALUE_SYMTAB_BLOCK abbrev id's.
40  VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
41  VST_ENTRY_7_ABBREV,
42  VST_ENTRY_6_ABBREV,
43  VST_BBENTRY_6_ABBREV,
44
45  // CONSTANTS_BLOCK abbrev id's.
46  CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
47  CONSTANTS_INTEGER_ABBREV,
48  CONSTANTS_CE_CAST_Abbrev,
49  CONSTANTS_NULL_Abbrev,
50
51  // FUNCTION_BLOCK abbrev id's.
52  FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
53  FUNCTION_INST_BINOP_ABBREV,
54  FUNCTION_INST_BINOP_FLAGS_ABBREV,
55  FUNCTION_INST_CAST_ABBREV,
56  FUNCTION_INST_RET_VOID_ABBREV,
57  FUNCTION_INST_RET_VAL_ABBREV,
58  FUNCTION_INST_UNREACHABLE_ABBREV
59};
60
61
62static unsigned GetEncodedCastOpcode(unsigned Opcode) {
63  switch (Opcode) {
64  default: llvm_unreachable("Unknown cast instruction!");
65  case Instruction::Trunc   : return bitc::CAST_TRUNC;
66  case Instruction::ZExt    : return bitc::CAST_ZEXT;
67  case Instruction::SExt    : return bitc::CAST_SEXT;
68  case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
69  case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
70  case Instruction::UIToFP  : return bitc::CAST_UITOFP;
71  case Instruction::SIToFP  : return bitc::CAST_SITOFP;
72  case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
73  case Instruction::FPExt   : return bitc::CAST_FPEXT;
74  case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
75  case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
76  case Instruction::BitCast : return bitc::CAST_BITCAST;
77  }
78}
79
80static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
81  switch (Opcode) {
82  default: llvm_unreachable("Unknown binary instruction!");
83  case Instruction::Add:
84  case Instruction::FAdd: return bitc::BINOP_ADD;
85  case Instruction::Sub:
86  case Instruction::FSub: return bitc::BINOP_SUB;
87  case Instruction::Mul:
88  case Instruction::FMul: return bitc::BINOP_MUL;
89  case Instruction::UDiv: return bitc::BINOP_UDIV;
90  case Instruction::FDiv:
91  case Instruction::SDiv: return bitc::BINOP_SDIV;
92  case Instruction::URem: return bitc::BINOP_UREM;
93  case Instruction::FRem:
94  case Instruction::SRem: return bitc::BINOP_SREM;
95  case Instruction::Shl:  return bitc::BINOP_SHL;
96  case Instruction::LShr: return bitc::BINOP_LSHR;
97  case Instruction::AShr: return bitc::BINOP_ASHR;
98  case Instruction::And:  return bitc::BINOP_AND;
99  case Instruction::Or:   return bitc::BINOP_OR;
100  case Instruction::Xor:  return bitc::BINOP_XOR;
101  }
102}
103
104
105
106static void WriteStringRecord(unsigned Code, const std::string &Str,
107                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
108  SmallVector<unsigned, 64> Vals;
109
110  // Code: [strchar x N]
111  for (unsigned i = 0, e = Str.size(); i != e; ++i)
112    Vals.push_back(Str[i]);
113
114  // Emit the finished record.
115  Stream.EmitRecord(Code, Vals, AbbrevToUse);
116}
117
118// Emit information about parameter attributes.
119static void WriteAttributeTable(const ValueEnumerator &VE,
120                                BitstreamWriter &Stream) {
121  const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
122  if (Attrs.empty()) return;
123
124  Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
125
126  SmallVector<uint64_t, 64> Record;
127  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
128    const AttrListPtr &A = Attrs[i];
129    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
130      const AttributeWithIndex &PAWI = A.getSlot(i);
131      Record.push_back(PAWI.Index);
132
133      // FIXME: remove in LLVM 3.0
134      // Store the alignment in the bitcode as a 16-bit raw value instead of a
135      // 5-bit log2 encoded value. Shift the bits above the alignment up by
136      // 11 bits.
137      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
138      if (PAWI.Attrs & Attribute::Alignment)
139        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
140      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
141
142      Record.push_back(FauxAttr);
143    }
144
145    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
146    Record.clear();
147  }
148
149  Stream.ExitBlock();
150}
151
152/// WriteTypeTable - Write out the type table for a module.
153static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
154  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
155
156  Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
157  SmallVector<uint64_t, 64> TypeVals;
158
159  // Abbrev for TYPE_CODE_POINTER.
160  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
161  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
162  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
163                            Log2_32_Ceil(VE.getTypes().size()+1)));
164  Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
165  unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
166
167  // Abbrev for TYPE_CODE_FUNCTION.
168  Abbv = new BitCodeAbbrev();
169  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
170  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
171  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
172  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
173  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
174                            Log2_32_Ceil(VE.getTypes().size()+1)));
175  unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
176
177  // Abbrev for TYPE_CODE_STRUCT.
178  Abbv = new BitCodeAbbrev();
179  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
180  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
181  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
182  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
183                            Log2_32_Ceil(VE.getTypes().size()+1)));
184  unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
185
186  // Abbrev for TYPE_CODE_ARRAY.
187  Abbv = new BitCodeAbbrev();
188  Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
189  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
190  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
191                            Log2_32_Ceil(VE.getTypes().size()+1)));
192  unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
193
194  // Emit an entry count so the reader can reserve space.
195  TypeVals.push_back(TypeList.size());
196  Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
197  TypeVals.clear();
198
199  // Loop over all of the types, emitting each in turn.
200  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
201    const Type *T = TypeList[i].first;
202    int AbbrevToUse = 0;
203    unsigned Code = 0;
204
205    switch (T->getTypeID()) {
206    default: llvm_unreachable("Unknown type!");
207    case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
208    case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
209    case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
210    case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
211    case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
212    case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
213    case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
214    case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
215    case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
216    case Type::IntegerTyID:
217      // INTEGER: [width]
218      Code = bitc::TYPE_CODE_INTEGER;
219      TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
220      break;
221    case Type::PointerTyID: {
222      const PointerType *PTy = cast<PointerType>(T);
223      // POINTER: [pointee type, address space]
224      Code = bitc::TYPE_CODE_POINTER;
225      TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
226      unsigned AddressSpace = PTy->getAddressSpace();
227      TypeVals.push_back(AddressSpace);
228      if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
229      break;
230    }
231    case Type::FunctionTyID: {
232      const FunctionType *FT = cast<FunctionType>(T);
233      // FUNCTION: [isvararg, attrid, retty, paramty x N]
234      Code = bitc::TYPE_CODE_FUNCTION;
235      TypeVals.push_back(FT->isVarArg());
236      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
237      TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
238      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
239        TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
240      AbbrevToUse = FunctionAbbrev;
241      break;
242    }
243    case Type::StructTyID: {
244      const StructType *ST = cast<StructType>(T);
245      // STRUCT: [ispacked, eltty x N]
246      Code = bitc::TYPE_CODE_STRUCT;
247      TypeVals.push_back(ST->isPacked());
248      // Output all of the element types.
249      for (StructType::element_iterator I = ST->element_begin(),
250           E = ST->element_end(); I != E; ++I)
251        TypeVals.push_back(VE.getTypeID(*I));
252      AbbrevToUse = StructAbbrev;
253      break;
254    }
255    case Type::ArrayTyID: {
256      const ArrayType *AT = cast<ArrayType>(T);
257      // ARRAY: [numelts, eltty]
258      Code = bitc::TYPE_CODE_ARRAY;
259      TypeVals.push_back(AT->getNumElements());
260      TypeVals.push_back(VE.getTypeID(AT->getElementType()));
261      AbbrevToUse = ArrayAbbrev;
262      break;
263    }
264    case Type::VectorTyID: {
265      const VectorType *VT = cast<VectorType>(T);
266      // VECTOR [numelts, eltty]
267      Code = bitc::TYPE_CODE_VECTOR;
268      TypeVals.push_back(VT->getNumElements());
269      TypeVals.push_back(VE.getTypeID(VT->getElementType()));
270      break;
271    }
272    }
273
274    // Emit the finished record.
275    Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
276    TypeVals.clear();
277  }
278
279  Stream.ExitBlock();
280}
281
282static unsigned getEncodedLinkage(const GlobalValue *GV) {
283  switch (GV->getLinkage()) {
284  default: llvm_unreachable("Invalid linkage!");
285  case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
286  case GlobalValue::ExternalLinkage:            return 0;
287  case GlobalValue::WeakAnyLinkage:             return 1;
288  case GlobalValue::AppendingLinkage:           return 2;
289  case GlobalValue::InternalLinkage:            return 3;
290  case GlobalValue::LinkOnceAnyLinkage:         return 4;
291  case GlobalValue::DLLImportLinkage:           return 5;
292  case GlobalValue::DLLExportLinkage:           return 6;
293  case GlobalValue::ExternalWeakLinkage:        return 7;
294  case GlobalValue::CommonLinkage:              return 8;
295  case GlobalValue::PrivateLinkage:             return 9;
296  case GlobalValue::WeakODRLinkage:             return 10;
297  case GlobalValue::LinkOnceODRLinkage:         return 11;
298  case GlobalValue::AvailableExternallyLinkage: return 12;
299  case GlobalValue::LinkerPrivateLinkage:       return 13;
300  }
301}
302
303static unsigned getEncodedVisibility(const GlobalValue *GV) {
304  switch (GV->getVisibility()) {
305  default: llvm_unreachable("Invalid visibility!");
306  case GlobalValue::DefaultVisibility:   return 0;
307  case GlobalValue::HiddenVisibility:    return 1;
308  case GlobalValue::ProtectedVisibility: return 2;
309  }
310}
311
312// Emit top-level description of module, including target triple, inline asm,
313// descriptors for global variables, and function prototype info.
314static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
315                            BitstreamWriter &Stream) {
316  // Emit the list of dependent libraries for the Module.
317  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
318    WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
319
320  // Emit various pieces of data attached to a module.
321  if (!M->getTargetTriple().empty())
322    WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
323                      0/*TODO*/, Stream);
324  if (!M->getDataLayout().empty())
325    WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
326                      0/*TODO*/, Stream);
327  if (!M->getModuleInlineAsm().empty())
328    WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
329                      0/*TODO*/, Stream);
330
331  // Emit information about sections and GC, computing how many there are. Also
332  // compute the maximum alignment value.
333  std::map<std::string, unsigned> SectionMap;
334  std::map<std::string, unsigned> GCMap;
335  unsigned MaxAlignment = 0;
336  unsigned MaxGlobalType = 0;
337  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
338       GV != E; ++GV) {
339    MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
340    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
341
342    if (!GV->hasSection()) continue;
343    // Give section names unique ID's.
344    unsigned &Entry = SectionMap[GV->getSection()];
345    if (Entry != 0) continue;
346    WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
347                      0/*TODO*/, Stream);
348    Entry = SectionMap.size();
349  }
350  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
351    MaxAlignment = std::max(MaxAlignment, F->getAlignment());
352    if (F->hasSection()) {
353      // Give section names unique ID's.
354      unsigned &Entry = SectionMap[F->getSection()];
355      if (!Entry) {
356        WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
357                          0/*TODO*/, Stream);
358        Entry = SectionMap.size();
359      }
360    }
361    if (F->hasGC()) {
362      // Same for GC names.
363      unsigned &Entry = GCMap[F->getGC()];
364      if (!Entry) {
365        WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
366                          0/*TODO*/, Stream);
367        Entry = GCMap.size();
368      }
369    }
370  }
371
372  // Emit abbrev for globals, now that we know # sections and max alignment.
373  unsigned SimpleGVarAbbrev = 0;
374  if (!M->global_empty()) {
375    // Add an abbrev for common globals with no visibility or thread localness.
376    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
377    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
378    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
379                              Log2_32_Ceil(MaxGlobalType+1)));
380    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
381    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
382    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
383    if (MaxAlignment == 0)                                      // Alignment.
384      Abbv->Add(BitCodeAbbrevOp(0));
385    else {
386      unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
387      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
388                               Log2_32_Ceil(MaxEncAlignment+1)));
389    }
390    if (SectionMap.empty())                                    // Section.
391      Abbv->Add(BitCodeAbbrevOp(0));
392    else
393      Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
394                               Log2_32_Ceil(SectionMap.size()+1)));
395    // Don't bother emitting vis + thread local.
396    SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
397  }
398
399  // Emit the global variable information.
400  SmallVector<unsigned, 64> Vals;
401  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
402       GV != E; ++GV) {
403    unsigned AbbrevToUse = 0;
404
405    // GLOBALVAR: [type, isconst, initid,
406    //             linkage, alignment, section, visibility, threadlocal]
407    Vals.push_back(VE.getTypeID(GV->getType()));
408    Vals.push_back(GV->isConstant());
409    Vals.push_back(GV->isDeclaration() ? 0 :
410                   (VE.getValueID(GV->getInitializer()) + 1));
411    Vals.push_back(getEncodedLinkage(GV));
412    Vals.push_back(Log2_32(GV->getAlignment())+1);
413    Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
414    if (GV->isThreadLocal() ||
415        GV->getVisibility() != GlobalValue::DefaultVisibility) {
416      Vals.push_back(getEncodedVisibility(GV));
417      Vals.push_back(GV->isThreadLocal());
418    } else {
419      AbbrevToUse = SimpleGVarAbbrev;
420    }
421
422    Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
423    Vals.clear();
424  }
425
426  // Emit the function proto information.
427  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
428    // FUNCTION:  [type, callingconv, isproto, paramattr,
429    //             linkage, alignment, section, visibility, gc]
430    Vals.push_back(VE.getTypeID(F->getType()));
431    Vals.push_back(F->getCallingConv());
432    Vals.push_back(F->isDeclaration());
433    Vals.push_back(getEncodedLinkage(F));
434    Vals.push_back(VE.getAttributeID(F->getAttributes()));
435    Vals.push_back(Log2_32(F->getAlignment())+1);
436    Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
437    Vals.push_back(getEncodedVisibility(F));
438    Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
439
440    unsigned AbbrevToUse = 0;
441    Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
442    Vals.clear();
443  }
444
445
446  // Emit the alias information.
447  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
448       AI != E; ++AI) {
449    Vals.push_back(VE.getTypeID(AI->getType()));
450    Vals.push_back(VE.getValueID(AI->getAliasee()));
451    Vals.push_back(getEncodedLinkage(AI));
452    Vals.push_back(getEncodedVisibility(AI));
453    unsigned AbbrevToUse = 0;
454    Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
455    Vals.clear();
456  }
457}
458
459static uint64_t GetOptimizationFlags(const Value *V) {
460  uint64_t Flags = 0;
461
462  if (const OverflowingBinaryOperator *OBO =
463        dyn_cast<OverflowingBinaryOperator>(V)) {
464    if (OBO->hasNoSignedOverflow())
465      Flags |= 1 << bitc::OBO_NO_SIGNED_OVERFLOW;
466    if (OBO->hasNoUnsignedOverflow())
467      Flags |= 1 << bitc::OBO_NO_UNSIGNED_OVERFLOW;
468  } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
469    if (Div->isExact())
470      Flags |= 1 << bitc::SDIV_EXACT;
471  }
472
473  return Flags;
474}
475
476 static void WriteModuleMetadata(const ValueEnumerator &VE,
477                                 BitstreamWriter &Stream) {
478   const ValueEnumerator::ValueList &Vals = VE.getValues();
479   bool StartedMetadataBlock = false;
480   unsigned MDSAbbrev = 0;
481   SmallVector<uint64_t, 64> Record;
482   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
483
484     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
485       if (!StartedMetadataBlock) {
486         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
487         StartedMetadataBlock = true;
488       }
489      for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
490        if (N->getElement(i)) {
491          Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
492          Record.push_back(VE.getValueID(N->getElement(i)));
493        } else {
494          Record.push_back(VE.getTypeID(Type::VoidTy));
495          Record.push_back(0);
496        }
497      }
498      Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
499      Record.clear();
500     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
501       if (!StartedMetadataBlock)  {
502        Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
503
504        // Abbrev for METADATA_STRING.
505        BitCodeAbbrev *Abbv = new BitCodeAbbrev();
506        Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
507        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
508        Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
509        MDSAbbrev = Stream.EmitAbbrev(Abbv);
510        StartedMetadataBlock = true;
511       }
512
513       // Code: [strchar x N]
514       const char *StrBegin = MDS->begin();
515       for (unsigned i = 0, e = MDS->length(); i != e; ++i)
516        Record.push_back(StrBegin[i]);
517
518       // Emit the finished record.
519      Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
520      Record.clear();
521     }
522   }
523
524   if (StartedMetadataBlock)
525     Stream.ExitBlock();
526}
527
528
529static void WriteConstants(unsigned FirstVal, unsigned LastVal,
530                           const ValueEnumerator &VE,
531                           BitstreamWriter &Stream, bool isGlobal) {
532  if (FirstVal == LastVal) return;
533
534  Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
535
536  unsigned AggregateAbbrev = 0;
537  unsigned String8Abbrev = 0;
538  unsigned CString7Abbrev = 0;
539  unsigned CString6Abbrev = 0;
540  // If this is a constant pool for the module, emit module-specific abbrevs.
541  if (isGlobal) {
542    // Abbrev for CST_CODE_AGGREGATE.
543    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
544    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
545    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
546    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
547    AggregateAbbrev = Stream.EmitAbbrev(Abbv);
548
549    // Abbrev for CST_CODE_STRING.
550    Abbv = new BitCodeAbbrev();
551    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
552    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
553    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
554    String8Abbrev = Stream.EmitAbbrev(Abbv);
555    // Abbrev for CST_CODE_CSTRING.
556    Abbv = new BitCodeAbbrev();
557    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
558    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
559    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
560    CString7Abbrev = Stream.EmitAbbrev(Abbv);
561    // Abbrev for CST_CODE_CSTRING.
562    Abbv = new BitCodeAbbrev();
563    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
564    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
565    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
566    CString6Abbrev = Stream.EmitAbbrev(Abbv);
567  }
568
569  SmallVector<uint64_t, 64> Record;
570
571  const ValueEnumerator::ValueList &Vals = VE.getValues();
572  const Type *LastTy = 0;
573  for (unsigned i = FirstVal; i != LastVal; ++i) {
574    const Value *V = Vals[i].first;
575    if (isa<MDString>(V) || isa<MDNode>(V))
576      continue;
577    // If we need to switch types, do so now.
578    if (V->getType() != LastTy) {
579      LastTy = V->getType();
580      Record.push_back(VE.getTypeID(LastTy));
581      Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
582                        CONSTANTS_SETTYPE_ABBREV);
583      Record.clear();
584    }
585
586    if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
587      Record.push_back(unsigned(IA->hasSideEffects()));
588
589      // Add the asm string.
590      const std::string &AsmStr = IA->getAsmString();
591      Record.push_back(AsmStr.size());
592      for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
593        Record.push_back(AsmStr[i]);
594
595      // Add the constraint string.
596      const std::string &ConstraintStr = IA->getConstraintString();
597      Record.push_back(ConstraintStr.size());
598      for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
599        Record.push_back(ConstraintStr[i]);
600      Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
601      Record.clear();
602      continue;
603    }
604    const Constant *C = cast<Constant>(V);
605    unsigned Code = -1U;
606    unsigned AbbrevToUse = 0;
607    if (C->isNullValue()) {
608      Code = bitc::CST_CODE_NULL;
609    } else if (isa<UndefValue>(C)) {
610      Code = bitc::CST_CODE_UNDEF;
611    } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
612      if (IV->getBitWidth() <= 64) {
613        int64_t V = IV->getSExtValue();
614        if (V >= 0)
615          Record.push_back(V << 1);
616        else
617          Record.push_back((-V << 1) | 1);
618        Code = bitc::CST_CODE_INTEGER;
619        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
620      } else {                             // Wide integers, > 64 bits in size.
621        // We have an arbitrary precision integer value to write whose
622        // bit width is > 64. However, in canonical unsigned integer
623        // format it is likely that the high bits are going to be zero.
624        // So, we only write the number of active words.
625        unsigned NWords = IV->getValue().getActiveWords();
626        const uint64_t *RawWords = IV->getValue().getRawData();
627        for (unsigned i = 0; i != NWords; ++i) {
628          int64_t V = RawWords[i];
629          if (V >= 0)
630            Record.push_back(V << 1);
631          else
632            Record.push_back((-V << 1) | 1);
633        }
634        Code = bitc::CST_CODE_WIDE_INTEGER;
635      }
636    } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
637      Code = bitc::CST_CODE_FLOAT;
638      const Type *Ty = CFP->getType();
639      if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
640        Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
641      } else if (Ty == Type::X86_FP80Ty) {
642        // api needed to prevent premature destruction
643        // bits are not in the same order as a normal i80 APInt, compensate.
644        APInt api = CFP->getValueAPF().bitcastToAPInt();
645        const uint64_t *p = api.getRawData();
646        Record.push_back((p[1] << 48) | (p[0] >> 16));
647        Record.push_back(p[0] & 0xffffLL);
648      } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
649        APInt api = CFP->getValueAPF().bitcastToAPInt();
650        const uint64_t *p = api.getRawData();
651        Record.push_back(p[0]);
652        Record.push_back(p[1]);
653      } else {
654        assert (0 && "Unknown FP type!");
655      }
656    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
657      // Emit constant strings specially.
658      unsigned NumOps = C->getNumOperands();
659      // If this is a null-terminated string, use the denser CSTRING encoding.
660      if (C->getOperand(NumOps-1)->isNullValue()) {
661        Code = bitc::CST_CODE_CSTRING;
662        --NumOps;  // Don't encode the null, which isn't allowed by char6.
663      } else {
664        Code = bitc::CST_CODE_STRING;
665        AbbrevToUse = String8Abbrev;
666      }
667      bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
668      bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
669      for (unsigned i = 0; i != NumOps; ++i) {
670        unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
671        Record.push_back(V);
672        isCStr7 &= (V & 128) == 0;
673        if (isCStrChar6)
674          isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
675      }
676
677      if (isCStrChar6)
678        AbbrevToUse = CString6Abbrev;
679      else if (isCStr7)
680        AbbrevToUse = CString7Abbrev;
681    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
682               isa<ConstantVector>(V)) {
683      Code = bitc::CST_CODE_AGGREGATE;
684      for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
685        Record.push_back(VE.getValueID(C->getOperand(i)));
686      AbbrevToUse = AggregateAbbrev;
687    } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
688      switch (CE->getOpcode()) {
689      default:
690        if (Instruction::isCast(CE->getOpcode())) {
691          Code = bitc::CST_CODE_CE_CAST;
692          Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
693          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
694          Record.push_back(VE.getValueID(C->getOperand(0)));
695          AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
696        } else {
697          assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
698          Code = bitc::CST_CODE_CE_BINOP;
699          Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
700          Record.push_back(VE.getValueID(C->getOperand(0)));
701          Record.push_back(VE.getValueID(C->getOperand(1)));
702          uint64_t Flags = GetOptimizationFlags(CE);
703          if (Flags != 0)
704            Record.push_back(Flags);
705        }
706        break;
707      case Instruction::GetElementPtr:
708        Code = bitc::CST_CODE_CE_GEP;
709        if (cast<GEPOperator>(C)->isInBounds())
710          Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
711        for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
712          Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
713          Record.push_back(VE.getValueID(C->getOperand(i)));
714        }
715        break;
716      case Instruction::Select:
717        Code = bitc::CST_CODE_CE_SELECT;
718        Record.push_back(VE.getValueID(C->getOperand(0)));
719        Record.push_back(VE.getValueID(C->getOperand(1)));
720        Record.push_back(VE.getValueID(C->getOperand(2)));
721        break;
722      case Instruction::ExtractElement:
723        Code = bitc::CST_CODE_CE_EXTRACTELT;
724        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
725        Record.push_back(VE.getValueID(C->getOperand(0)));
726        Record.push_back(VE.getValueID(C->getOperand(1)));
727        break;
728      case Instruction::InsertElement:
729        Code = bitc::CST_CODE_CE_INSERTELT;
730        Record.push_back(VE.getValueID(C->getOperand(0)));
731        Record.push_back(VE.getValueID(C->getOperand(1)));
732        Record.push_back(VE.getValueID(C->getOperand(2)));
733        break;
734      case Instruction::ShuffleVector:
735        // If the return type and argument types are the same, this is a
736        // standard shufflevector instruction.  If the types are different,
737        // then the shuffle is widening or truncating the input vectors, and
738        // the argument type must also be encoded.
739        if (C->getType() == C->getOperand(0)->getType()) {
740          Code = bitc::CST_CODE_CE_SHUFFLEVEC;
741        } else {
742          Code = bitc::CST_CODE_CE_SHUFVEC_EX;
743          Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
744        }
745        Record.push_back(VE.getValueID(C->getOperand(0)));
746        Record.push_back(VE.getValueID(C->getOperand(1)));
747        Record.push_back(VE.getValueID(C->getOperand(2)));
748        break;
749      case Instruction::ICmp:
750      case Instruction::FCmp:
751        Code = bitc::CST_CODE_CE_CMP;
752        Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
753        Record.push_back(VE.getValueID(C->getOperand(0)));
754        Record.push_back(VE.getValueID(C->getOperand(1)));
755        Record.push_back(CE->getPredicate());
756        break;
757      }
758    } else {
759      llvm_unreachable("Unknown constant!");
760    }
761    Stream.EmitRecord(Code, Record, AbbrevToUse);
762    Record.clear();
763  }
764
765  Stream.ExitBlock();
766}
767
768static void WriteModuleConstants(const ValueEnumerator &VE,
769                                 BitstreamWriter &Stream) {
770  const ValueEnumerator::ValueList &Vals = VE.getValues();
771
772  // Find the first constant to emit, which is the first non-globalvalue value.
773  // We know globalvalues have been emitted by WriteModuleInfo.
774  for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
775    if (!isa<GlobalValue>(Vals[i].first)) {
776      WriteConstants(i, Vals.size(), VE, Stream, true);
777      return;
778    }
779  }
780}
781
782/// PushValueAndType - The file has to encode both the value and type id for
783/// many values, because we need to know what type to create for forward
784/// references.  However, most operands are not forward references, so this type
785/// field is not needed.
786///
787/// This function adds V's value ID to Vals.  If the value ID is higher than the
788/// instruction ID, then it is a forward reference, and it also includes the
789/// type ID.
790static bool PushValueAndType(const Value *V, unsigned InstID,
791                             SmallVector<unsigned, 64> &Vals,
792                             ValueEnumerator &VE) {
793  unsigned ValID = VE.getValueID(V);
794  Vals.push_back(ValID);
795  if (ValID >= InstID) {
796    Vals.push_back(VE.getTypeID(V->getType()));
797    return true;
798  }
799  return false;
800}
801
802/// WriteInstruction - Emit an instruction to the specified stream.
803static void WriteInstruction(const Instruction &I, unsigned InstID,
804                             ValueEnumerator &VE, BitstreamWriter &Stream,
805                             SmallVector<unsigned, 64> &Vals) {
806  unsigned Code = 0;
807  unsigned AbbrevToUse = 0;
808  switch (I.getOpcode()) {
809  default:
810    if (Instruction::isCast(I.getOpcode())) {
811      Code = bitc::FUNC_CODE_INST_CAST;
812      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
813        AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
814      Vals.push_back(VE.getTypeID(I.getType()));
815      Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
816    } else {
817      assert(isa<BinaryOperator>(I) && "Unknown instruction!");
818      Code = bitc::FUNC_CODE_INST_BINOP;
819      if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
820        AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
821      Vals.push_back(VE.getValueID(I.getOperand(1)));
822      Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
823      uint64_t Flags = GetOptimizationFlags(&I);
824      if (Flags != 0) {
825        if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
826          AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
827        Vals.push_back(Flags);
828      }
829    }
830    break;
831
832  case Instruction::GetElementPtr:
833    Code = bitc::FUNC_CODE_INST_GEP;
834    if (cast<GEPOperator>(&I)->isInBounds())
835      Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
836    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
837      PushValueAndType(I.getOperand(i), InstID, Vals, VE);
838    break;
839  case Instruction::ExtractValue: {
840    Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
841    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
842    const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
843    for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
844      Vals.push_back(*i);
845    break;
846  }
847  case Instruction::InsertValue: {
848    Code = bitc::FUNC_CODE_INST_INSERTVAL;
849    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
850    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
851    const InsertValueInst *IVI = cast<InsertValueInst>(&I);
852    for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
853      Vals.push_back(*i);
854    break;
855  }
856  case Instruction::Select:
857    Code = bitc::FUNC_CODE_INST_VSELECT;
858    PushValueAndType(I.getOperand(1), InstID, Vals, VE);
859    Vals.push_back(VE.getValueID(I.getOperand(2)));
860    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
861    break;
862  case Instruction::ExtractElement:
863    Code = bitc::FUNC_CODE_INST_EXTRACTELT;
864    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
865    Vals.push_back(VE.getValueID(I.getOperand(1)));
866    break;
867  case Instruction::InsertElement:
868    Code = bitc::FUNC_CODE_INST_INSERTELT;
869    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
870    Vals.push_back(VE.getValueID(I.getOperand(1)));
871    Vals.push_back(VE.getValueID(I.getOperand(2)));
872    break;
873  case Instruction::ShuffleVector:
874    Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
875    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
876    Vals.push_back(VE.getValueID(I.getOperand(1)));
877    Vals.push_back(VE.getValueID(I.getOperand(2)));
878    break;
879  case Instruction::ICmp:
880  case Instruction::FCmp:
881    // compare returning Int1Ty or vector of Int1Ty
882    Code = bitc::FUNC_CODE_INST_CMP2;
883    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
884    Vals.push_back(VE.getValueID(I.getOperand(1)));
885    Vals.push_back(cast<CmpInst>(I).getPredicate());
886    break;
887
888  case Instruction::Ret:
889    {
890      Code = bitc::FUNC_CODE_INST_RET;
891      unsigned NumOperands = I.getNumOperands();
892      if (NumOperands == 0)
893        AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
894      else if (NumOperands == 1) {
895        if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
896          AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
897      } else {
898        for (unsigned i = 0, e = NumOperands; i != e; ++i)
899          PushValueAndType(I.getOperand(i), InstID, Vals, VE);
900      }
901    }
902    break;
903  case Instruction::Br:
904    {
905      Code = bitc::FUNC_CODE_INST_BR;
906      BranchInst &II(cast<BranchInst>(I));
907      Vals.push_back(VE.getValueID(II.getSuccessor(0)));
908      if (II.isConditional()) {
909        Vals.push_back(VE.getValueID(II.getSuccessor(1)));
910        Vals.push_back(VE.getValueID(II.getCondition()));
911      }
912    }
913    break;
914  case Instruction::Switch:
915    Code = bitc::FUNC_CODE_INST_SWITCH;
916    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
917    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
918      Vals.push_back(VE.getValueID(I.getOperand(i)));
919    break;
920  case Instruction::Invoke: {
921    const InvokeInst *II = cast<InvokeInst>(&I);
922    const Value *Callee(II->getCalledValue());
923    const PointerType *PTy = cast<PointerType>(Callee->getType());
924    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
925    Code = bitc::FUNC_CODE_INST_INVOKE;
926
927    Vals.push_back(VE.getAttributeID(II->getAttributes()));
928    Vals.push_back(II->getCallingConv());
929    Vals.push_back(VE.getValueID(II->getNormalDest()));
930    Vals.push_back(VE.getValueID(II->getUnwindDest()));
931    PushValueAndType(Callee, InstID, Vals, VE);
932
933    // Emit value #'s for the fixed parameters.
934    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
935      Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
936
937    // Emit type/value pairs for varargs params.
938    if (FTy->isVarArg()) {
939      for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
940           i != e; ++i)
941        PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
942    }
943    break;
944  }
945  case Instruction::Unwind:
946    Code = bitc::FUNC_CODE_INST_UNWIND;
947    break;
948  case Instruction::Unreachable:
949    Code = bitc::FUNC_CODE_INST_UNREACHABLE;
950    AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
951    break;
952
953  case Instruction::PHI:
954    Code = bitc::FUNC_CODE_INST_PHI;
955    Vals.push_back(VE.getTypeID(I.getType()));
956    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
957      Vals.push_back(VE.getValueID(I.getOperand(i)));
958    break;
959
960  case Instruction::Malloc:
961    Code = bitc::FUNC_CODE_INST_MALLOC;
962    Vals.push_back(VE.getTypeID(I.getType()));
963    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
964    Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
965    break;
966
967  case Instruction::Free:
968    Code = bitc::FUNC_CODE_INST_FREE;
969    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
970    break;
971
972  case Instruction::Alloca:
973    Code = bitc::FUNC_CODE_INST_ALLOCA;
974    Vals.push_back(VE.getTypeID(I.getType()));
975    Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
976    Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
977    break;
978
979  case Instruction::Load:
980    Code = bitc::FUNC_CODE_INST_LOAD;
981    if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
982      AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
983
984    Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
985    Vals.push_back(cast<LoadInst>(I).isVolatile());
986    break;
987  case Instruction::Store:
988    Code = bitc::FUNC_CODE_INST_STORE2;
989    PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
990    Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
991    Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
992    Vals.push_back(cast<StoreInst>(I).isVolatile());
993    break;
994  case Instruction::Call: {
995    const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
996    const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
997
998    Code = bitc::FUNC_CODE_INST_CALL;
999
1000    const CallInst *CI = cast<CallInst>(&I);
1001    Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1002    Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1003    PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1004
1005    // Emit value #'s for the fixed parameters.
1006    for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1007      Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1008
1009    // Emit type/value pairs for varargs params.
1010    if (FTy->isVarArg()) {
1011      unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1012      for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1013           i != e; ++i)
1014        PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1015    }
1016    break;
1017  }
1018  case Instruction::VAArg:
1019    Code = bitc::FUNC_CODE_INST_VAARG;
1020    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1021    Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1022    Vals.push_back(VE.getTypeID(I.getType())); // restype.
1023    break;
1024  }
1025
1026  Stream.EmitRecord(Code, Vals, AbbrevToUse);
1027  Vals.clear();
1028}
1029
1030// Emit names for globals/functions etc.
1031static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1032                                  const ValueEnumerator &VE,
1033                                  BitstreamWriter &Stream) {
1034  if (VST.empty()) return;
1035  Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1036
1037  // FIXME: Set up the abbrev, we know how many values there are!
1038  // FIXME: We know if the type names can use 7-bit ascii.
1039  SmallVector<unsigned, 64> NameVals;
1040
1041  for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1042       SI != SE; ++SI) {
1043
1044    const ValueName &Name = *SI;
1045
1046    // Figure out the encoding to use for the name.
1047    bool is7Bit = true;
1048    bool isChar6 = true;
1049    for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1050         C != E; ++C) {
1051      if (isChar6)
1052        isChar6 = BitCodeAbbrevOp::isChar6(*C);
1053      if ((unsigned char)*C & 128) {
1054        is7Bit = false;
1055        break;  // don't bother scanning the rest.
1056      }
1057    }
1058
1059    unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1060
1061    // VST_ENTRY:   [valueid, namechar x N]
1062    // VST_BBENTRY: [bbid, namechar x N]
1063    unsigned Code;
1064    if (isa<BasicBlock>(SI->getValue())) {
1065      Code = bitc::VST_CODE_BBENTRY;
1066      if (isChar6)
1067        AbbrevToUse = VST_BBENTRY_6_ABBREV;
1068    } else {
1069      Code = bitc::VST_CODE_ENTRY;
1070      if (isChar6)
1071        AbbrevToUse = VST_ENTRY_6_ABBREV;
1072      else if (is7Bit)
1073        AbbrevToUse = VST_ENTRY_7_ABBREV;
1074    }
1075
1076    NameVals.push_back(VE.getValueID(SI->getValue()));
1077    for (const char *P = Name.getKeyData(),
1078         *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1079      NameVals.push_back((unsigned char)*P);
1080
1081    // Emit the finished record.
1082    Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1083    NameVals.clear();
1084  }
1085  Stream.ExitBlock();
1086}
1087
1088/// WriteFunction - Emit a function body to the module stream.
1089static void WriteFunction(const Function &F, ValueEnumerator &VE,
1090                          BitstreamWriter &Stream) {
1091  Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1092  VE.incorporateFunction(F);
1093
1094  SmallVector<unsigned, 64> Vals;
1095
1096  // Emit the number of basic blocks, so the reader can create them ahead of
1097  // time.
1098  Vals.push_back(VE.getBasicBlocks().size());
1099  Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1100  Vals.clear();
1101
1102  // If there are function-local constants, emit them now.
1103  unsigned CstStart, CstEnd;
1104  VE.getFunctionConstantRange(CstStart, CstEnd);
1105  WriteConstants(CstStart, CstEnd, VE, Stream, false);
1106
1107  // Keep a running idea of what the instruction ID is.
1108  unsigned InstID = CstEnd;
1109
1110  // Finally, emit all the instructions, in order.
1111  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1112    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1113         I != E; ++I) {
1114      WriteInstruction(*I, InstID, VE, Stream, Vals);
1115      if (I->getType() != Type::VoidTy)
1116        ++InstID;
1117    }
1118
1119  // Emit names for all the instructions etc.
1120  WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1121
1122  VE.purgeFunction();
1123  Stream.ExitBlock();
1124}
1125
1126/// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1127static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1128                                 const ValueEnumerator &VE,
1129                                 BitstreamWriter &Stream) {
1130  if (TST.empty()) return;
1131
1132  Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1133
1134  // 7-bit fixed width VST_CODE_ENTRY strings.
1135  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1136  Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1137  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1138                            Log2_32_Ceil(VE.getTypes().size()+1)));
1139  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1140  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1141  unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1142
1143  SmallVector<unsigned, 64> NameVals;
1144
1145  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1146       TI != TE; ++TI) {
1147    // TST_ENTRY: [typeid, namechar x N]
1148    NameVals.push_back(VE.getTypeID(TI->second));
1149
1150    const std::string &Str = TI->first;
1151    bool is7Bit = true;
1152    for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1153      NameVals.push_back((unsigned char)Str[i]);
1154      if (Str[i] & 128)
1155        is7Bit = false;
1156    }
1157
1158    // Emit the finished record.
1159    Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1160    NameVals.clear();
1161  }
1162
1163  Stream.ExitBlock();
1164}
1165
1166// Emit blockinfo, which defines the standard abbreviations etc.
1167static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1168  // We only want to emit block info records for blocks that have multiple
1169  // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1170  // blocks can defined their abbrevs inline.
1171  Stream.EnterBlockInfoBlock(2);
1172
1173  { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1174    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1175    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1176    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1177    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1178    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1179    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1180                                   Abbv) != VST_ENTRY_8_ABBREV)
1181      llvm_unreachable("Unexpected abbrev ordering!");
1182  }
1183
1184  { // 7-bit fixed width VST_ENTRY strings.
1185    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1186    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1187    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1188    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1189    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1190    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1191                                   Abbv) != VST_ENTRY_7_ABBREV)
1192      llvm_unreachable("Unexpected abbrev ordering!");
1193  }
1194  { // 6-bit char6 VST_ENTRY strings.
1195    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1196    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1197    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1198    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1199    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1200    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1201                                   Abbv) != VST_ENTRY_6_ABBREV)
1202      llvm_unreachable("Unexpected abbrev ordering!");
1203  }
1204  { // 6-bit char6 VST_BBENTRY strings.
1205    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1206    Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1207    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1208    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1209    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1210    if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1211                                   Abbv) != VST_BBENTRY_6_ABBREV)
1212      llvm_unreachable("Unexpected abbrev ordering!");
1213  }
1214
1215
1216
1217  { // SETTYPE abbrev for CONSTANTS_BLOCK.
1218    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1219    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1220    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1221                              Log2_32_Ceil(VE.getTypes().size()+1)));
1222    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1223                                   Abbv) != CONSTANTS_SETTYPE_ABBREV)
1224      llvm_unreachable("Unexpected abbrev ordering!");
1225  }
1226
1227  { // INTEGER abbrev for CONSTANTS_BLOCK.
1228    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1229    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1230    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1231    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1232                                   Abbv) != CONSTANTS_INTEGER_ABBREV)
1233      llvm_unreachable("Unexpected abbrev ordering!");
1234  }
1235
1236  { // CE_CAST abbrev for CONSTANTS_BLOCK.
1237    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1238    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1239    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1240    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1241                              Log2_32_Ceil(VE.getTypes().size()+1)));
1242    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1243
1244    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1245                                   Abbv) != CONSTANTS_CE_CAST_Abbrev)
1246      llvm_unreachable("Unexpected abbrev ordering!");
1247  }
1248  { // NULL abbrev for CONSTANTS_BLOCK.
1249    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1250    Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1251    if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1252                                   Abbv) != CONSTANTS_NULL_Abbrev)
1253      llvm_unreachable("Unexpected abbrev ordering!");
1254  }
1255
1256  // FIXME: This should only use space for first class types!
1257
1258  { // INST_LOAD abbrev for FUNCTION_BLOCK.
1259    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1260    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1261    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1262    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1263    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1264    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1265                                   Abbv) != FUNCTION_INST_LOAD_ABBREV)
1266      llvm_unreachable("Unexpected abbrev ordering!");
1267  }
1268  { // INST_BINOP abbrev for FUNCTION_BLOCK.
1269    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1270    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1271    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1272    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1273    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1274    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1275                                   Abbv) != FUNCTION_INST_BINOP_ABBREV)
1276      llvm_unreachable("Unexpected abbrev ordering!");
1277  }
1278  { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1279    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1280    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1281    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1282    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1283    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1284    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1285    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1286                                   Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1287      llvm_unreachable("Unexpected abbrev ordering!");
1288  }
1289  { // INST_CAST abbrev for FUNCTION_BLOCK.
1290    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1291    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1292    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1293    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1294                              Log2_32_Ceil(VE.getTypes().size()+1)));
1295    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1296    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1297                                   Abbv) != FUNCTION_INST_CAST_ABBREV)
1298      llvm_unreachable("Unexpected abbrev ordering!");
1299  }
1300
1301  { // INST_RET abbrev for FUNCTION_BLOCK.
1302    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1303    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1304    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1305                                   Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1306      llvm_unreachable("Unexpected abbrev ordering!");
1307  }
1308  { // INST_RET abbrev for FUNCTION_BLOCK.
1309    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1310    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1311    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1312    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1313                                   Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1314      llvm_unreachable("Unexpected abbrev ordering!");
1315  }
1316  { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1317    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1318    Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1319    if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1320                                   Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1321      llvm_unreachable("Unexpected abbrev ordering!");
1322  }
1323
1324  Stream.ExitBlock();
1325}
1326
1327
1328/// WriteModule - Emit the specified module to the bitstream.
1329static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1330  Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1331
1332  // Emit the version number if it is non-zero.
1333  if (CurVersion) {
1334    SmallVector<unsigned, 1> Vals;
1335    Vals.push_back(CurVersion);
1336    Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1337  }
1338
1339  // Analyze the module, enumerating globals, functions, etc.
1340  ValueEnumerator VE(M);
1341
1342  // Emit blockinfo, which defines the standard abbreviations etc.
1343  WriteBlockInfo(VE, Stream);
1344
1345  // Emit information about parameter attributes.
1346  WriteAttributeTable(VE, Stream);
1347
1348  // Emit information describing all of the types in the module.
1349  WriteTypeTable(VE, Stream);
1350
1351  // Emit top-level description of module, including target triple, inline asm,
1352  // descriptors for global variables, and function prototype info.
1353  WriteModuleInfo(M, VE, Stream);
1354
1355  // Emit constants.
1356  WriteModuleConstants(VE, Stream);
1357
1358  // Emit metadata.
1359  WriteModuleMetadata(VE, Stream);
1360
1361  // Emit function bodies.
1362  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1363    if (!I->isDeclaration())
1364      WriteFunction(*I, VE, Stream);
1365
1366  // Emit the type symbol table information.
1367  WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1368
1369  // Emit names for globals/functions etc.
1370  WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1371
1372  Stream.ExitBlock();
1373}
1374
1375/// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1376/// header and trailer to make it compatible with the system archiver.  To do
1377/// this we emit the following header, and then emit a trailer that pads the
1378/// file out to be a multiple of 16 bytes.
1379///
1380/// struct bc_header {
1381///   uint32_t Magic;         // 0x0B17C0DE
1382///   uint32_t Version;       // Version, currently always 0.
1383///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1384///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1385///   uint32_t CPUType;       // CPU specifier.
1386///   ... potentially more later ...
1387/// };
1388enum {
1389  DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1390  DarwinBCHeaderSize = 5*4
1391};
1392
1393static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1394                               const std::string &TT) {
1395  unsigned CPUType = ~0U;
1396
1397  // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1398  // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1399  // specific constants here because they are implicitly part of the Darwin ABI.
1400  enum {
1401    DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1402    DARWIN_CPU_TYPE_X86        = 7,
1403    DARWIN_CPU_TYPE_POWERPC    = 18
1404  };
1405
1406  if (TT.find("x86_64-") == 0)
1407    CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1408  else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1409           TT[4] == '-' && TT[1] - '3' < 6)
1410    CPUType = DARWIN_CPU_TYPE_X86;
1411  else if (TT.find("powerpc-") == 0)
1412    CPUType = DARWIN_CPU_TYPE_POWERPC;
1413  else if (TT.find("powerpc64-") == 0)
1414    CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1415
1416  // Traditional Bitcode starts after header.
1417  unsigned BCOffset = DarwinBCHeaderSize;
1418
1419  Stream.Emit(0x0B17C0DE, 32);
1420  Stream.Emit(0         , 32);  // Version.
1421  Stream.Emit(BCOffset  , 32);
1422  Stream.Emit(0         , 32);  // Filled in later.
1423  Stream.Emit(CPUType   , 32);
1424}
1425
1426/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1427/// finalize the header.
1428static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1429  // Update the size field in the header.
1430  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1431
1432  // If the file is not a multiple of 16 bytes, insert dummy padding.
1433  while (BufferSize & 15) {
1434    Stream.Emit(0, 8);
1435    ++BufferSize;
1436  }
1437}
1438
1439
1440/// WriteBitcodeToFile - Write the specified module to the specified output
1441/// stream.
1442void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1443  raw_os_ostream RawOut(Out);
1444  // If writing to stdout, set binary mode.
1445  if (llvm::cout == Out)
1446    sys::Program::ChangeStdoutToBinary();
1447  WriteBitcodeToFile(M, RawOut);
1448}
1449
1450/// WriteBitcodeToFile - Write the specified module to the specified output
1451/// stream.
1452void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1453  std::vector<unsigned char> Buffer;
1454  BitstreamWriter Stream(Buffer);
1455
1456  Buffer.reserve(256*1024);
1457
1458  WriteBitcodeToStream( M, Stream );
1459
1460  // If writing to stdout, set binary mode.
1461  if (&llvm::outs() == &Out)
1462    sys::Program::ChangeStdoutToBinary();
1463
1464  // Write the generated bitstream to "Out".
1465  Out.write((char*)&Buffer.front(), Buffer.size());
1466
1467  // Make sure it hits disk now.
1468  Out.flush();
1469}
1470
1471/// WriteBitcodeToStream - Write the specified module to the specified output
1472/// stream.
1473void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1474  // If this is darwin, emit a file header and trailer if needed.
1475  bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1476  if (isDarwin)
1477    EmitDarwinBCHeader(Stream, M->getTargetTriple());
1478
1479  // Emit the file header.
1480  Stream.Emit((unsigned)'B', 8);
1481  Stream.Emit((unsigned)'C', 8);
1482  Stream.Emit(0x0, 4);
1483  Stream.Emit(0xC, 4);
1484  Stream.Emit(0xE, 4);
1485  Stream.Emit(0xD, 4);
1486
1487  // Emit the module.
1488  WriteModule(M, Stream);
1489
1490  if (isDarwin)
1491    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1492}
1493