lib/Bitcode/Writer/BitcodeWriter.cpp

   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/Module.h"
  23 #include "llvm/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include "llvm/System/Program.h"
  29 using namespace llvm;
  30
  31 /// These are manifest constants used by the bitcode writer. They do not need to
  32 /// be kept in sync with the reader, but need to be consistent within this file.
  33 enum {
  34   CurVersion = 0,
  35
  36   // VALUE_SYMTAB_BLOCK abbrev id's.
  37   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  38   VST_ENTRY_7_ABBREV,
  39   VST_ENTRY_6_ABBREV,
  40   VST_BBENTRY_6_ABBREV,
  41
  42   // CONSTANTS_BLOCK abbrev id's.
  43   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  44   CONSTANTS_INTEGER_ABBREV,
  45   CONSTANTS_CE_CAST_Abbrev,
  46   CONSTANTS_NULL_Abbrev,
  47
  48   // FUNCTION_BLOCK abbrev id's.
  49   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  50   FUNCTION_INST_BINOP_ABBREV,
  51   FUNCTION_INST_CAST_ABBREV,
  52   FUNCTION_INST_RET_VOID_ABBREV,
  53   FUNCTION_INST_RET_VAL_ABBREV,
  54   FUNCTION_INST_UNREACHABLE_ABBREV
  55 };
  56
  57
  58 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  59   switch (Opcode) {
  60   default: assert(0 && "Unknown cast instruction!");
  61   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  62   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  63   case Instruction::SExt    : return bitc::CAST_SEXT;
  64   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  65   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  66   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  67   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  68   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  69   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  70   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  71   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  72   case Instruction::BitCast : return bitc::CAST_BITCAST;
  73   }
  74 }
  75
  76 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  77   switch (Opcode) {
  78   default: assert(0 && "Unknown binary instruction!");
  79   case Instruction::Add:  return bitc::BINOP_ADD;
  80   case Instruction::Sub:  return bitc::BINOP_SUB;
  81   case Instruction::Mul:  return bitc::BINOP_MUL;
  82   case Instruction::UDiv: return bitc::BINOP_UDIV;
  83   case Instruction::FDiv:
  84   case Instruction::SDiv: return bitc::BINOP_SDIV;
  85   case Instruction::URem: return bitc::BINOP_UREM;
  86   case Instruction::FRem:
  87   case Instruction::SRem: return bitc::BINOP_SREM;
  88   case Instruction::Shl:  return bitc::BINOP_SHL;
  89   case Instruction::LShr: return bitc::BINOP_LSHR;
  90   case Instruction::AShr: return bitc::BINOP_ASHR;
  91   case Instruction::And:  return bitc::BINOP_AND;
  92   case Instruction::Or:   return bitc::BINOP_OR;
  93   case Instruction::Xor:  return bitc::BINOP_XOR;
  94   }
  95 }
  96
  97
  98
  99 static void WriteStringRecord(unsigned Code, const std::string &Str,
 100                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 101   SmallVector<unsigned, 64> Vals;
 102
 103   // Code: [strchar x N]
 104   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 105     Vals.push_back(Str[i]);
 106
 107   // Emit the finished record.
 108   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 109 }
 110
 111 // Emit information about parameter attributes.
 112 static void WriteAttributeTable(const ValueEnumerator &VE,
 113                                 BitstreamWriter &Stream) {
 114   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 115   if (Attrs.empty()) return;
 116
 117   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 118
 119   SmallVector<uint64_t, 64> Record;
 120   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 121     const AttrListPtr &A = Attrs[i];
 122     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 123       const AttributeWithIndex &PAWI = A.getSlot(i);
 124       Record.push_back(PAWI.Index);
 125
 126       // FIXME: remove in LLVM 3.0
 127       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 128       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 129       // 11 bits.
 130       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 131       if (PAWI.Attrs & Attribute::Alignment)
 132         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 133       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 134
 135       Record.push_back(FauxAttr);
 136     }
 137
 138     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 139     Record.clear();
 140   }
 141
 142   Stream.ExitBlock();
 143 }
 144
 145 /// WriteTypeTable - Write out the type table for a module.
 146 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 147   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 148
 149   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 150   SmallVector<uint64_t, 64> TypeVals;
 151
 152   // Abbrev for TYPE_CODE_POINTER.
 153   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 154   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 156                             Log2_32_Ceil(VE.getTypes().size()+1)));
 157   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 158   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 159
 160   // Abbrev for TYPE_CODE_FUNCTION.
 161   Abbv = new BitCodeAbbrev();
 162   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 164   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 167                             Log2_32_Ceil(VE.getTypes().size()+1)));
 168   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 169
 170   // Abbrev for TYPE_CODE_STRUCT.
 171   Abbv = new BitCodeAbbrev();
 172   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 176                             Log2_32_Ceil(VE.getTypes().size()+1)));
 177   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 178
 179   // Abbrev for TYPE_CODE_ARRAY.
 180   Abbv = new BitCodeAbbrev();
 181   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 184                             Log2_32_Ceil(VE.getTypes().size()+1)));
 185   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 186
 187   // Emit an entry count so the reader can reserve space.
 188   TypeVals.push_back(TypeList.size());
 189   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 190   TypeVals.clear();
 191
 192   // Loop over all of the types, emitting each in turn.
 193   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 194     const Type *T = TypeList[i].first;
 195     int AbbrevToUse = 0;
 196     unsigned Code = 0;
 197
 198     switch (T->getTypeID()) {
 199     default: assert(0 && "Unknown type!");
 200     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 201     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 202     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 203     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 204     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 205     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 206     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 207     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 208     case Type::IntegerTyID:
 209       // INTEGER: [width]
 210       Code = bitc::TYPE_CODE_INTEGER;
 211       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 212       break;
 213     case Type::PointerTyID: {
 214       const PointerType *PTy = cast<PointerType>(T);
 215       // POINTER: [pointee type, address space]
 216       Code = bitc::TYPE_CODE_POINTER;
 217       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 218       unsigned AddressSpace = PTy->getAddressSpace();
 219       TypeVals.push_back(AddressSpace);
 220       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 221       break;
 222     }
 223     case Type::FunctionTyID: {
 224       const FunctionType *FT = cast<FunctionType>(T);
 225       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 226       Code = bitc::TYPE_CODE_FUNCTION;
 227       TypeVals.push_back(FT->isVarArg());
 228       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 229       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 230       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 231         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 232       AbbrevToUse = FunctionAbbrev;
 233       break;
 234     }
 235     case Type::StructTyID: {
 236       const StructType *ST = cast<StructType>(T);
 237       // STRUCT: [ispacked, eltty x N]
 238       Code = bitc::TYPE_CODE_STRUCT;
 239       TypeVals.push_back(ST->isPacked());
 240       // Output all of the element types.
 241       for (StructType::element_iterator I = ST->element_begin(),
 242            E = ST->element_end(); I != E; ++I)
 243         TypeVals.push_back(VE.getTypeID(*I));
 244       AbbrevToUse = StructAbbrev;
 245       break;
 246     }
 247     case Type::ArrayTyID: {
 248       const ArrayType *AT = cast<ArrayType>(T);
 249       // ARRAY: [numelts, eltty]
 250       Code = bitc::TYPE_CODE_ARRAY;
 251       TypeVals.push_back(AT->getNumElements());
 252       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 253       AbbrevToUse = ArrayAbbrev;
 254       break;
 255     }
 256     case Type::VectorTyID: {
 257       const VectorType *VT = cast<VectorType>(T);
 258       // VECTOR [numelts, eltty]
 259       Code = bitc::TYPE_CODE_VECTOR;
 260       TypeVals.push_back(VT->getNumElements());
 261       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 262       break;
 263     }
 264     }
 265
 266     // Emit the finished record.
 267     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 268     TypeVals.clear();
 269   }
 270
 271   Stream.ExitBlock();
 272 }
 273
 274 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 275   switch (GV->getLinkage()) {
 276   default: assert(0 && "Invalid linkage!");
 277   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 278   case GlobalValue::ExternalLinkage:     return 0;
 279   case GlobalValue::WeakAnyLinkage:      return 1;
 280   case GlobalValue::AppendingLinkage:    return 2;
 281   case GlobalValue::InternalLinkage:     return 3;
 282   case GlobalValue::LinkOnceAnyLinkage:  return 4;
 283   case GlobalValue::DLLImportLinkage:    return 5;
 284   case GlobalValue::DLLExportLinkage:    return 6;
 285   case GlobalValue::ExternalWeakLinkage: return 7;
 286   case GlobalValue::CommonLinkage:       return 8;
 287   case GlobalValue::PrivateLinkage:      return 9;
 288   case GlobalValue::WeakODRLinkage:      return 10;
 289   case GlobalValue::LinkOnceODRLinkage:  return 11;
 290   }
 291 }
 292
 293 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 294   switch (GV->getVisibility()) {
 295   default: assert(0 && "Invalid visibility!");
 296   case GlobalValue::DefaultVisibility:   return 0;
 297   case GlobalValue::HiddenVisibility:    return 1;
 298   case GlobalValue::ProtectedVisibility: return 2;
 299   }
 300 }
 301
 302 // Emit top-level description of module, including target triple, inline asm,
 303 // descriptors for global variables, and function prototype info.
 304 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 305                             BitstreamWriter &Stream) {
 306   // Emit the list of dependent libraries for the Module.
 307   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 308     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 309
 310   // Emit various pieces of data attached to a module.
 311   if (!M->getTargetTriple().empty())
 312     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 313                       0/*TODO*/, Stream);
 314   if (!M->getDataLayout().empty())
 315     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 316                       0/*TODO*/, Stream);
 317   if (!M->getModuleInlineAsm().empty())
 318     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 319                       0/*TODO*/, Stream);
 320
 321   // Emit information about sections and GC, computing how many there are. Also
 322   // compute the maximum alignment value.
 323   std::map<std::string, unsigned> SectionMap;
 324   std::map<std::string, unsigned> GCMap;
 325   unsigned MaxAlignment = 0;
 326   unsigned MaxGlobalType = 0;
 327   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 328        GV != E; ++GV) {
 329     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 330     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 331
 332     if (!GV->hasSection()) continue;
 333     // Give section names unique ID's.
 334     unsigned &Entry = SectionMap[GV->getSection()];
 335     if (Entry != 0) continue;
 336     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 337                       0/*TODO*/, Stream);
 338     Entry = SectionMap.size();
 339   }
 340   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 341     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 342     if (F->hasSection()) {
 343       // Give section names unique ID's.
 344       unsigned &Entry = SectionMap[F->getSection()];
 345       if (!Entry) {
 346         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 347                           0/*TODO*/, Stream);
 348         Entry = SectionMap.size();
 349       }
 350     }
 351     if (F->hasGC()) {
 352       // Same for GC names.
 353       unsigned &Entry = GCMap[F->getGC()];
 354       if (!Entry) {
 355         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 356                           0/*TODO*/, Stream);
 357         Entry = GCMap.size();
 358       }
 359     }
 360   }
 361
 362   // Emit abbrev for globals, now that we know # sections and max alignment.
 363   unsigned SimpleGVarAbbrev = 0;
 364   if (!M->global_empty()) {
 365     // Add an abbrev for common globals with no visibility or thread localness.
 366     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 367     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 368     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 369                               Log2_32_Ceil(MaxGlobalType+1)));
 370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 373     if (MaxAlignment == 0)                                      // Alignment.
 374       Abbv->Add(BitCodeAbbrevOp(0));
 375     else {
 376       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 377       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 378                                Log2_32_Ceil(MaxEncAlignment+1)));
 379     }
 380     if (SectionMap.empty())                                    // Section.
 381       Abbv->Add(BitCodeAbbrevOp(0));
 382     else
 383       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 384                                Log2_32_Ceil(SectionMap.size()+1)));
 385     // Don't bother emitting vis + thread local.
 386     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 387   }
 388
 389   // Emit the global variable information.
 390   SmallVector<unsigned, 64> Vals;
 391   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 392        GV != E; ++GV) {
 393     unsigned AbbrevToUse = 0;
 394
 395     // GLOBALVAR: [type, isconst, initid,
 396     //             linkage, alignment, section, visibility, threadlocal]
 397     Vals.push_back(VE.getTypeID(GV->getType()));
 398     Vals.push_back(GV->isConstant());
 399     Vals.push_back(GV->isDeclaration() ? 0 :
 400                    (VE.getValueID(GV->getInitializer()) + 1));
 401     Vals.push_back(getEncodedLinkage(GV));
 402     Vals.push_back(Log2_32(GV->getAlignment())+1);
 403     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 404     if (GV->isThreadLocal() ||
 405         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 406       Vals.push_back(getEncodedVisibility(GV));
 407       Vals.push_back(GV->isThreadLocal());
 408     } else {
 409       AbbrevToUse = SimpleGVarAbbrev;
 410     }
 411
 412     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 413     Vals.clear();
 414   }
 415
 416   // Emit the function proto information.
 417   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 418     // FUNCTION:  [type, callingconv, isproto, paramattr,
 419     //             linkage, alignment, section, visibility, gc]
 420     Vals.push_back(VE.getTypeID(F->getType()));
 421     Vals.push_back(F->getCallingConv());
 422     Vals.push_back(F->isDeclaration());
 423     Vals.push_back(getEncodedLinkage(F));
 424     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 425     Vals.push_back(Log2_32(F->getAlignment())+1);
 426     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 427     Vals.push_back(getEncodedVisibility(F));
 428     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 429
 430     unsigned AbbrevToUse = 0;
 431     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 432     Vals.clear();
 433   }
 434
 435
 436   // Emit the alias information.
 437   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 438        AI != E; ++AI) {
 439     Vals.push_back(VE.getTypeID(AI->getType()));
 440     Vals.push_back(VE.getValueID(AI->getAliasee()));
 441     Vals.push_back(getEncodedLinkage(AI));
 442     Vals.push_back(getEncodedVisibility(AI));
 443     unsigned AbbrevToUse = 0;
 444     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 445     Vals.clear();
 446   }
 447 }
 448
 449
 450 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 451                            const ValueEnumerator &VE,
 452                            BitstreamWriter &Stream, bool isGlobal) {
 453   if (FirstVal == LastVal) return;
 454
 455   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 456
 457   unsigned AggregateAbbrev = 0;
 458   unsigned String8Abbrev = 0;
 459   unsigned CString7Abbrev = 0;
 460   unsigned CString6Abbrev = 0;
 461   unsigned MDString8Abbrev = 0;
 462   unsigned MDString6Abbrev = 0;
 463   // If this is a constant pool for the module, emit module-specific abbrevs.
 464   if (isGlobal) {
 465     // Abbrev for CST_CODE_AGGREGATE.
 466     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 467     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 470     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 471
 472     // Abbrev for CST_CODE_STRING.
 473     Abbv = new BitCodeAbbrev();
 474     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 477     String8Abbrev = Stream.EmitAbbrev(Abbv);
 478     // Abbrev for CST_CODE_CSTRING.
 479     Abbv = new BitCodeAbbrev();
 480     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 483     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 484     // Abbrev for CST_CODE_CSTRING.
 485     Abbv = new BitCodeAbbrev();
 486     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 489     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 490
 491     // Abbrev for CST_CODE_MDSTRING.
 492     Abbv = new BitCodeAbbrev();
 493     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 496     MDString8Abbrev = Stream.EmitAbbrev(Abbv);
 497     // Abbrev for CST_CODE_MDSTRING.
 498     Abbv = new BitCodeAbbrev();
 499     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 502     MDString6Abbrev = Stream.EmitAbbrev(Abbv);
 503   }
 504
 505   SmallVector<uint64_t, 64> Record;
 506
 507   const ValueEnumerator::ValueList &Vals = VE.getValues();
 508   const Type *LastTy = 0;
 509   for (unsigned i = FirstVal; i != LastVal; ++i) {
 510     const Value *V = Vals[i].first;
 511     // If we need to switch types, do so now.
 512     if (V->getType() != LastTy) {
 513       LastTy = V->getType();
 514       Record.push_back(VE.getTypeID(LastTy));
 515       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 516                         CONSTANTS_SETTYPE_ABBREV);
 517       Record.clear();
 518     }
 519
 520     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 521       Record.push_back(unsigned(IA->hasSideEffects()));
 522
 523       // Add the asm string.
 524       const std::string &AsmStr = IA->getAsmString();
 525       Record.push_back(AsmStr.size());
 526       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 527         Record.push_back(AsmStr[i]);
 528
 529       // Add the constraint string.
 530       const std::string &ConstraintStr = IA->getConstraintString();
 531       Record.push_back(ConstraintStr.size());
 532       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 533         Record.push_back(ConstraintStr[i]);
 534       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 535       Record.clear();
 536       continue;
 537     }
 538     const Constant *C = cast<Constant>(V);
 539     unsigned Code = -1U;
 540     unsigned AbbrevToUse = 0;
 541     if (C->isNullValue()) {
 542       Code = bitc::CST_CODE_NULL;
 543     } else if (isa<UndefValue>(C)) {
 544       Code = bitc::CST_CODE_UNDEF;
 545     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 546       if (IV->getBitWidth() <= 64) {
 547         int64_t V = IV->getSExtValue();
 548         if (V >= 0)
 549           Record.push_back(V << 1);
 550         else
 551           Record.push_back((-V << 1) | 1);
 552         Code = bitc::CST_CODE_INTEGER;
 553         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 554       } else {                             // Wide integers, > 64 bits in size.
 555         // We have an arbitrary precision integer value to write whose
 556         // bit width is > 64. However, in canonical unsigned integer
 557         // format it is likely that the high bits are going to be zero.
 558         // So, we only write the number of active words.
 559         unsigned NWords = IV->getValue().getActiveWords();
 560         const uint64_t *RawWords = IV->getValue().getRawData();
 561         for (unsigned i = 0; i != NWords; ++i) {
 562           int64_t V = RawWords[i];
 563           if (V >= 0)
 564             Record.push_back(V << 1);
 565           else
 566             Record.push_back((-V << 1) | 1);
 567         }
 568         Code = bitc::CST_CODE_WIDE_INTEGER;
 569       }
 570     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 571       Code = bitc::CST_CODE_FLOAT;
 572       const Type *Ty = CFP->getType();
 573       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 574         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 575       } else if (Ty == Type::X86_FP80Ty) {
 576         // api needed to prevent premature destruction
 577         // bits are not in the same order as a normal i80 APInt, compensate.
 578         APInt api = CFP->getValueAPF().bitcastToAPInt();
 579         const uint64_t *p = api.getRawData();
 580         Record.push_back((p[1] << 48) | (p[0] >> 16));
 581         Record.push_back(p[0] & 0xffffLL);
 582       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 583         APInt api = CFP->getValueAPF().bitcastToAPInt();
 584         const uint64_t *p = api.getRawData();
 585         Record.push_back(p[0]);
 586         Record.push_back(p[1]);
 587       } else {
 588         assert (0 && "Unknown FP type!");
 589       }
 590     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 591       // Emit constant strings specially.
 592       unsigned NumOps = C->getNumOperands();
 593       // If this is a null-terminated string, use the denser CSTRING encoding.
 594       if (C->getOperand(NumOps-1)->isNullValue()) {
 595         Code = bitc::CST_CODE_CSTRING;
 596         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 597       } else {
 598         Code = bitc::CST_CODE_STRING;
 599         AbbrevToUse = String8Abbrev;
 600       }
 601       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 602       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 603       for (unsigned i = 0; i != NumOps; ++i) {
 604         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 605         Record.push_back(V);
 606         isCStr7 &= (V & 128) == 0;
 607         if (isCStrChar6)
 608           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 609       }
 610
 611       if (isCStrChar6)
 612         AbbrevToUse = CString6Abbrev;
 613       else if (isCStr7)
 614         AbbrevToUse = CString7Abbrev;
 615     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 616                isa<ConstantVector>(V)) {
 617       Code = bitc::CST_CODE_AGGREGATE;
 618       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 619         Record.push_back(VE.getValueID(C->getOperand(i)));
 620       AbbrevToUse = AggregateAbbrev;
 621     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 622       switch (CE->getOpcode()) {
 623       default:
 624         if (Instruction::isCast(CE->getOpcode())) {
 625           Code = bitc::CST_CODE_CE_CAST;
 626           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 627           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 628           Record.push_back(VE.getValueID(C->getOperand(0)));
 629           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 630         } else {
 631           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 632           Code = bitc::CST_CODE_CE_BINOP;
 633           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 634           Record.push_back(VE.getValueID(C->getOperand(0)));
 635           Record.push_back(VE.getValueID(C->getOperand(1)));
 636         }
 637         break;
 638       case Instruction::GetElementPtr:
 639         Code = bitc::CST_CODE_CE_GEP;
 640         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 641           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 642           Record.push_back(VE.getValueID(C->getOperand(i)));
 643         }
 644         break;
 645       case Instruction::Select:
 646         Code = bitc::CST_CODE_CE_SELECT;
 647         Record.push_back(VE.getValueID(C->getOperand(0)));
 648         Record.push_back(VE.getValueID(C->getOperand(1)));
 649         Record.push_back(VE.getValueID(C->getOperand(2)));
 650         break;
 651       case Instruction::ExtractElement:
 652         Code = bitc::CST_CODE_CE_EXTRACTELT;
 653         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 654         Record.push_back(VE.getValueID(C->getOperand(0)));
 655         Record.push_back(VE.getValueID(C->getOperand(1)));
 656         break;
 657       case Instruction::InsertElement:
 658         Code = bitc::CST_CODE_CE_INSERTELT;
 659         Record.push_back(VE.getValueID(C->getOperand(0)));
 660         Record.push_back(VE.getValueID(C->getOperand(1)));
 661         Record.push_back(VE.getValueID(C->getOperand(2)));
 662         break;
 663       case Instruction::ShuffleVector:
 664         // If the return type and argument types are the same, this is a
 665         // standard shufflevector instruction.  If the types are different,
 666         // then the shuffle is widening or truncating the input vectors, and
 667         // the argument type must also be encoded.
 668         if (C->getType() == C->getOperand(0)->getType()) {
 669           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 670         } else {
 671           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 672           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 673         }
 674         Record.push_back(VE.getValueID(C->getOperand(0)));
 675         Record.push_back(VE.getValueID(C->getOperand(1)));
 676         Record.push_back(VE.getValueID(C->getOperand(2)));
 677         break;
 678       case Instruction::ICmp:
 679       case Instruction::FCmp:
 680       case Instruction::VICmp:
 681       case Instruction::VFCmp:
 682         if (isa<VectorType>(C->getOperand(0)->getType())
 683             && (CE->getOpcode() == Instruction::ICmp
 684                 || CE->getOpcode() == Instruction::FCmp)) {
 685           // compare returning vector of Int1Ty
 686           assert(0 && "Unsupported constant!");
 687         } else {
 688           Code = bitc::CST_CODE_CE_CMP;
 689         }
 690         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 691         Record.push_back(VE.getValueID(C->getOperand(0)));
 692         Record.push_back(VE.getValueID(C->getOperand(1)));
 693         Record.push_back(CE->getPredicate());
 694         break;
 695       }
 696     } else if (const MDString *S = dyn_cast<MDString>(C)) {
 697       Code = bitc::CST_CODE_MDSTRING;
 698       AbbrevToUse = MDString6Abbrev;
 699       for (unsigned i = 0, e = S->size(); i != e; ++i) {
 700         char V = S->begin()[i];
 701         Record.push_back(V);
 702
 703         if (!BitCodeAbbrevOp::isChar6(V))
 704           AbbrevToUse = MDString8Abbrev;
 705       }
 706     } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
 707       Code = bitc::CST_CODE_MDNODE;
 708       for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 709         Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 710         Record.push_back(VE.getValueID(N->getOperand(i)));
 711       }
 712     } else {
 713       assert(0 && "Unknown constant!");
 714     }
 715     Stream.EmitRecord(Code, Record, AbbrevToUse);
 716     Record.clear();
 717   }
 718
 719   Stream.ExitBlock();
 720 }
 721
 722 static void WriteModuleConstants(const ValueEnumerator &VE,
 723                                  BitstreamWriter &Stream) {
 724   const ValueEnumerator::ValueList &Vals = VE.getValues();
 725
 726   // Find the first constant to emit, which is the first non-globalvalue value.
 727   // We know globalvalues have been emitted by WriteModuleInfo.
 728   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 729     if (!isa<GlobalValue>(Vals[i].first)) {
 730       WriteConstants(i, Vals.size(), VE, Stream, true);
 731       return;
 732     }
 733   }
 734 }
 735
 736 /// PushValueAndType - The file has to encode both the value and type id for
 737 /// many values, because we need to know what type to create for forward
 738 /// references.  However, most operands are not forward references, so this type
 739 /// field is not needed.
 740 ///
 741 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 742 /// instruction ID, then it is a forward reference, and it also includes the
 743 /// type ID.
 744 static bool PushValueAndType(const Value *V, unsigned InstID,
 745                              SmallVector<unsigned, 64> &Vals,
 746                              ValueEnumerator &VE) {
 747   unsigned ValID = VE.getValueID(V);
 748   Vals.push_back(ValID);
 749   if (ValID >= InstID) {
 750     Vals.push_back(VE.getTypeID(V->getType()));
 751     return true;
 752   }
 753   return false;
 754 }
 755
 756 /// WriteInstruction - Emit an instruction to the specified stream.
 757 static void WriteInstruction(const Instruction &I, unsigned InstID,
 758                              ValueEnumerator &VE, BitstreamWriter &Stream,
 759                              SmallVector<unsigned, 64> &Vals) {
 760   unsigned Code = 0;
 761   unsigned AbbrevToUse = 0;
 762   switch (I.getOpcode()) {
 763   default:
 764     if (Instruction::isCast(I.getOpcode())) {
 765       Code = bitc::FUNC_CODE_INST_CAST;
 766       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 767         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 768       Vals.push_back(VE.getTypeID(I.getType()));
 769       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 770     } else {
 771       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 772       Code = bitc::FUNC_CODE_INST_BINOP;
 773       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 774         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 775       Vals.push_back(VE.getValueID(I.getOperand(1)));
 776       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 777     }
 778     break;
 779
 780   case Instruction::GetElementPtr:
 781     Code = bitc::FUNC_CODE_INST_GEP;
 782     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 783       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 784     break;
 785   case Instruction::ExtractValue: {
 786     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 787     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 788     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 789     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 790       Vals.push_back(*i);
 791     break;
 792   }
 793   case Instruction::InsertValue: {
 794     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 795     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 796     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 797     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 798     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 799       Vals.push_back(*i);
 800     break;
 801   }
 802   case Instruction::Select:
 803     Code = bitc::FUNC_CODE_INST_VSELECT;
 804     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 805     Vals.push_back(VE.getValueID(I.getOperand(2)));
 806     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 807     break;
 808   case Instruction::ExtractElement:
 809     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 810     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 811     Vals.push_back(VE.getValueID(I.getOperand(1)));
 812     break;
 813   case Instruction::InsertElement:
 814     Code = bitc::FUNC_CODE_INST_INSERTELT;
 815     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 816     Vals.push_back(VE.getValueID(I.getOperand(1)));
 817     Vals.push_back(VE.getValueID(I.getOperand(2)));
 818     break;
 819   case Instruction::ShuffleVector:
 820     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 821     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 822     Vals.push_back(VE.getValueID(I.getOperand(1)));
 823     Vals.push_back(VE.getValueID(I.getOperand(2)));
 824     break;
 825   case Instruction::ICmp:
 826   case Instruction::FCmp:
 827   case Instruction::VICmp:
 828   case Instruction::VFCmp:
 829     if (I.getOpcode() == Instruction::ICmp
 830         || I.getOpcode() == Instruction::FCmp) {
 831       // compare returning Int1Ty or vector of Int1Ty
 832       Code = bitc::FUNC_CODE_INST_CMP2;
 833     } else {
 834       Code = bitc::FUNC_CODE_INST_CMP;
 835     }
 836     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 837     Vals.push_back(VE.getValueID(I.getOperand(1)));
 838     Vals.push_back(cast<CmpInst>(I).getPredicate());
 839     break;
 840
 841   case Instruction::Ret:
 842     {
 843       Code = bitc::FUNC_CODE_INST_RET;
 844       unsigned NumOperands = I.getNumOperands();
 845       if (NumOperands == 0)
 846         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 847       else if (NumOperands == 1) {
 848         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 849           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 850       } else {
 851         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 852           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 853       }
 854     }
 855     break;
 856   case Instruction::Br:
 857     {
 858       Code = bitc::FUNC_CODE_INST_BR;
 859       BranchInst &II(cast<BranchInst>(I));
 860       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 861       if (II.isConditional()) {
 862         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 863         Vals.push_back(VE.getValueID(II.getCondition()));
 864       }
 865     }
 866     break;
 867   case Instruction::Switch:
 868     Code = bitc::FUNC_CODE_INST_SWITCH;
 869     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 870     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 871       Vals.push_back(VE.getValueID(I.getOperand(i)));
 872     break;
 873   case Instruction::Invoke: {
 874     const InvokeInst *II = cast<InvokeInst>(&I);
 875     const Value *Callee(II->getCalledValue());
 876     const PointerType *PTy = cast<PointerType>(Callee->getType());
 877     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 878     Code = bitc::FUNC_CODE_INST_INVOKE;
 879
 880     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 881     Vals.push_back(II->getCallingConv());
 882     Vals.push_back(VE.getValueID(II->getNormalDest()));
 883     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 884     PushValueAndType(Callee, InstID, Vals, VE);
 885
 886     // Emit value #'s for the fixed parameters.
 887     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 888       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 889
 890     // Emit type/value pairs for varargs params.
 891     if (FTy->isVarArg()) {
 892       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 893            i != e; ++i)
 894         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 895     }
 896     break;
 897   }
 898   case Instruction::Unwind:
 899     Code = bitc::FUNC_CODE_INST_UNWIND;
 900     break;
 901   case Instruction::Unreachable:
 902     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 903     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 904     break;
 905
 906   case Instruction::PHI:
 907     Code = bitc::FUNC_CODE_INST_PHI;
 908     Vals.push_back(VE.getTypeID(I.getType()));
 909     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 910       Vals.push_back(VE.getValueID(I.getOperand(i)));
 911     break;
 912
 913   case Instruction::Malloc:
 914     Code = bitc::FUNC_CODE_INST_MALLOC;
 915     Vals.push_back(VE.getTypeID(I.getType()));
 916     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 917     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 918     break;
 919
 920   case Instruction::Free:
 921     Code = bitc::FUNC_CODE_INST_FREE;
 922     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 923     break;
 924
 925   case Instruction::Alloca:
 926     Code = bitc::FUNC_CODE_INST_ALLOCA;
 927     Vals.push_back(VE.getTypeID(I.getType()));
 928     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 929     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 930     break;
 931
 932   case Instruction::Load:
 933     Code = bitc::FUNC_CODE_INST_LOAD;
 934     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 935       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 936
 937     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 938     Vals.push_back(cast<LoadInst>(I).isVolatile());
 939     break;
 940   case Instruction::Store:
 941     Code = bitc::FUNC_CODE_INST_STORE2;
 942     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 943     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 944     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 945     Vals.push_back(cast<StoreInst>(I).isVolatile());
 946     break;
 947   case Instruction::Call: {
 948     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 949     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 950
 951     Code = bitc::FUNC_CODE_INST_CALL;
 952
 953     const CallInst *CI = cast<CallInst>(&I);
 954     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 955     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 956     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 957
 958     // Emit value #'s for the fixed parameters.
 959     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 960       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 961
 962     // Emit type/value pairs for varargs params.
 963     if (FTy->isVarArg()) {
 964       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 965       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 966            i != e; ++i)
 967         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 968     }
 969     break;
 970   }
 971   case Instruction::VAArg:
 972     Code = bitc::FUNC_CODE_INST_VAARG;
 973     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 974     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 975     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 976     break;
 977   }
 978
 979   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 980   Vals.clear();
 981 }
 982
 983 // Emit names for globals/functions etc.
 984 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 985                                   const ValueEnumerator &VE,
 986                                   BitstreamWriter &Stream) {
 987   if (VST.empty()) return;
 988   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 989
 990   // FIXME: Set up the abbrev, we know how many values there are!
 991   // FIXME: We know if the type names can use 7-bit ascii.
 992   SmallVector<unsigned, 64> NameVals;
 993
 994   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 995        SI != SE; ++SI) {
 996
 997     const ValueName &Name = *SI;
 998
 999     // Figure out the encoding to use for the name.
1000     bool is7Bit = true;
1001     bool isChar6 = true;
1002     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1003          C != E; ++C) {
1004       if (isChar6)
1005         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1006       if ((unsigned char)*C & 128) {
1007         is7Bit = false;
1008         break;  // don't bother scanning the rest.
1009       }
1010     }
1011
1012     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1013
1014     // VST_ENTRY:   [valueid, namechar x N]
1015     // VST_BBENTRY: [bbid, namechar x N]
1016     unsigned Code;
1017     if (isa<BasicBlock>(SI->getValue())) {
1018       Code = bitc::VST_CODE_BBENTRY;
1019       if (isChar6)
1020         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1021     } else {
1022       Code = bitc::VST_CODE_ENTRY;
1023       if (isChar6)
1024         AbbrevToUse = VST_ENTRY_6_ABBREV;
1025       else if (is7Bit)
1026         AbbrevToUse = VST_ENTRY_7_ABBREV;
1027     }
1028
1029     NameVals.push_back(VE.getValueID(SI->getValue()));
1030     for (const char *P = Name.getKeyData(),
1031          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1032       NameVals.push_back((unsigned char)*P);
1033
1034     // Emit the finished record.
1035     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1036     NameVals.clear();
1037   }
1038   Stream.ExitBlock();
1039 }
1040
1041 /// WriteFunction - Emit a function body to the module stream.
1042 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1043                           BitstreamWriter &Stream) {
1044   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1045   VE.incorporateFunction(F);
1046
1047   SmallVector<unsigned, 64> Vals;
1048
1049   // Emit the number of basic blocks, so the reader can create them ahead of
1050   // time.
1051   Vals.push_back(VE.getBasicBlocks().size());
1052   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1053   Vals.clear();
1054
1055   // If there are function-local constants, emit them now.
1056   unsigned CstStart, CstEnd;
1057   VE.getFunctionConstantRange(CstStart, CstEnd);
1058   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1059
1060   // Keep a running idea of what the instruction ID is.
1061   unsigned InstID = CstEnd;
1062
1063   // Finally, emit all the instructions, in order.
1064   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1065     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1066          I != E; ++I) {
1067       WriteInstruction(*I, InstID, VE, Stream, Vals);
1068       if (I->getType() != Type::VoidTy)
1069         ++InstID;
1070     }
1071
1072   // Emit names for all the instructions etc.
1073   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1074
1075   VE.purgeFunction();
1076   Stream.ExitBlock();
1077 }
1078
1079 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1080 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1081                                  const ValueEnumerator &VE,
1082                                  BitstreamWriter &Stream) {
1083   if (TST.empty()) return;
1084
1085   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1086
1087   // 7-bit fixed width VST_CODE_ENTRY strings.
1088   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1089   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1091                             Log2_32_Ceil(VE.getTypes().size()+1)));
1092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1094   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1095
1096   SmallVector<unsigned, 64> NameVals;
1097
1098   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1099        TI != TE; ++TI) {
1100     // TST_ENTRY: [typeid, namechar x N]
1101     NameVals.push_back(VE.getTypeID(TI->second));
1102
1103     const std::string &Str = TI->first;
1104     bool is7Bit = true;
1105     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1106       NameVals.push_back((unsigned char)Str[i]);
1107       if (Str[i] & 128)
1108         is7Bit = false;
1109     }
1110
1111     // Emit the finished record.
1112     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1113     NameVals.clear();
1114   }
1115
1116   Stream.ExitBlock();
1117 }
1118
1119 // Emit blockinfo, which defines the standard abbreviations etc.
1120 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1121   // We only want to emit block info records for blocks that have multiple
1122   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1123   // blocks can defined their abbrevs inline.
1124   Stream.EnterBlockInfoBlock(2);
1125
1126   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1127     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1128     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1129     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1130     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1131     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1132     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1133                                    Abbv) != VST_ENTRY_8_ABBREV)
1134       assert(0 && "Unexpected abbrev ordering!");
1135   }
1136
1137   { // 7-bit fixed width VST_ENTRY strings.
1138     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1139     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1140     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1141     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1142     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1143     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1144                                    Abbv) != VST_ENTRY_7_ABBREV)
1145       assert(0 && "Unexpected abbrev ordering!");
1146   }
1147   { // 6-bit char6 VST_ENTRY strings.
1148     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1149     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1151     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1152     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1153     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1154                                    Abbv) != VST_ENTRY_6_ABBREV)
1155       assert(0 && "Unexpected abbrev ordering!");
1156   }
1157   { // 6-bit char6 VST_BBENTRY strings.
1158     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1159     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1161     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1162     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1163     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1164                                    Abbv) != VST_BBENTRY_6_ABBREV)
1165       assert(0 && "Unexpected abbrev ordering!");
1166   }
1167
1168
1169
1170   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1171     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1172     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1174                               Log2_32_Ceil(VE.getTypes().size()+1)));
1175     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1176                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1177       assert(0 && "Unexpected abbrev ordering!");
1178   }
1179
1180   { // INTEGER abbrev for CONSTANTS_BLOCK.
1181     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1182     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1184     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1185                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1186       assert(0 && "Unexpected abbrev ordering!");
1187   }
1188
1189   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1190     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1191     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1194                               Log2_32_Ceil(VE.getTypes().size()+1)));
1195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1196
1197     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1198                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1199       assert(0 && "Unexpected abbrev ordering!");
1200   }
1201   { // NULL abbrev for CONSTANTS_BLOCK.
1202     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1203     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1204     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1205                                    Abbv) != CONSTANTS_NULL_Abbrev)
1206       assert(0 && "Unexpected abbrev ordering!");
1207   }
1208
1209   // FIXME: This should only use space for first class types!
1210
1211   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1212     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1213     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1214     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1217     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1218                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1219       assert(0 && "Unexpected abbrev ordering!");
1220   }
1221   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1222     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1223     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1227     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1228                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1229       assert(0 && "Unexpected abbrev ordering!");
1230   }
1231   { // INST_CAST abbrev for FUNCTION_BLOCK.
1232     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1233     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1236                               Log2_32_Ceil(VE.getTypes().size()+1)));
1237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1238     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1239                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1240       assert(0 && "Unexpected abbrev ordering!");
1241   }
1242
1243   { // INST_RET abbrev for FUNCTION_BLOCK.
1244     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1245     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1246     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1247                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1248       assert(0 && "Unexpected abbrev ordering!");
1249   }
1250   { // INST_RET abbrev for FUNCTION_BLOCK.
1251     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1252     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1254     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1255                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1256       assert(0 && "Unexpected abbrev ordering!");
1257   }
1258   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1259     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1260     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1261     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1262                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1263       assert(0 && "Unexpected abbrev ordering!");
1264   }
1265
1266   Stream.ExitBlock();
1267 }
1268
1269
1270 /// WriteModule - Emit the specified module to the bitstream.
1271 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1272   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1273
1274   // Emit the version number if it is non-zero.
1275   if (CurVersion) {
1276     SmallVector<unsigned, 1> Vals;
1277     Vals.push_back(CurVersion);
1278     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1279   }
1280
1281   // Analyze the module, enumerating globals, functions, etc.
1282   ValueEnumerator VE(M);
1283
1284   // Emit blockinfo, which defines the standard abbreviations etc.
1285   WriteBlockInfo(VE, Stream);
1286
1287   // Emit information about parameter attributes.
1288   WriteAttributeTable(VE, Stream);
1289
1290   // Emit information describing all of the types in the module.
1291   WriteTypeTable(VE, Stream);
1292
1293   // Emit top-level description of module, including target triple, inline asm,
1294   // descriptors for global variables, and function prototype info.
1295   WriteModuleInfo(M, VE, Stream);
1296
1297   // Emit constants.
1298   WriteModuleConstants(VE, Stream);
1299
1300   // If we have any aggregate values in the value table, purge them - these can
1301   // only be used to initialize global variables.  Doing so makes the value
1302   // namespace smaller for code in functions.
1303   int NumNonAggregates = VE.PurgeAggregateValues();
1304   if (NumNonAggregates != -1) {
1305     SmallVector<unsigned, 1> Vals;
1306     Vals.push_back(NumNonAggregates);
1307     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1308   }
1309
1310   // Emit function bodies.
1311   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1312     if (!I->isDeclaration())
1313       WriteFunction(*I, VE, Stream);
1314
1315   // Emit the type symbol table information.
1316   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1317
1318   // Emit names for globals/functions etc.
1319   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1320
1321   Stream.ExitBlock();
1322 }
1323
1324 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1325 /// header and trailer to make it compatible with the system archiver.  To do
1326 /// this we emit the following header, and then emit a trailer that pads the
1327 /// file out to be a multiple of 16 bytes.
1328 ///
1329 /// struct bc_header {
1330 ///   uint32_t Magic;         // 0x0B17C0DE
1331 ///   uint32_t Version;       // Version, currently always 0.
1332 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1333 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1334 ///   uint32_t CPUType;       // CPU specifier.
1335 ///   ... potentially more later ...
1336 /// };
1337 enum {
1338   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1339   DarwinBCHeaderSize = 5*4
1340 };
1341
1342 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1343                                const std::string &TT) {
1344   unsigned CPUType = ~0U;
1345
1346   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1347   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1348   // specific constants here because they are implicitly part of the Darwin ABI.
1349   enum {
1350     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1351     DARWIN_CPU_TYPE_X86        = 7,
1352     DARWIN_CPU_TYPE_POWERPC    = 18
1353   };
1354
1355   if (TT.find("x86_64-") == 0)
1356     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1357   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1358            TT[4] == '-' && TT[1] - '3' < 6)
1359     CPUType = DARWIN_CPU_TYPE_X86;
1360   else if (TT.find("powerpc-") == 0)
1361     CPUType = DARWIN_CPU_TYPE_POWERPC;
1362   else if (TT.find("powerpc64-") == 0)
1363     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1364
1365   // Traditional Bitcode starts after header.
1366   unsigned BCOffset = DarwinBCHeaderSize;
1367
1368   Stream.Emit(0x0B17C0DE, 32);
1369   Stream.Emit(0         , 32);  // Version.
1370   Stream.Emit(BCOffset  , 32);
1371   Stream.Emit(0         , 32);  // Filled in later.
1372   Stream.Emit(CPUType   , 32);
1373 }
1374
1375 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1376 /// finalize the header.
1377 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1378   // Update the size field in the header.
1379   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1380
1381   // If the file is not a multiple of 16 bytes, insert dummy padding.
1382   while (BufferSize & 15) {
1383     Stream.Emit(0, 8);
1384     ++BufferSize;
1385   }
1386 }
1387
1388
1389 /// WriteBitcodeToFile - Write the specified module to the specified output
1390 /// stream.
1391 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1392   raw_os_ostream RawOut(Out);
1393   // If writing to stdout, set binary mode.
1394   if (llvm::cout == Out)
1395     sys::Program::ChangeStdoutToBinary();
1396   WriteBitcodeToFile(M, RawOut);
1397 }
1398
1399 /// WriteBitcodeToFile - Write the specified module to the specified output
1400 /// stream.
1401 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1402   std::vector<unsigned char> Buffer;
1403   BitstreamWriter Stream(Buffer);
1404
1405   Buffer.reserve(256*1024);
1406
1407   WriteBitcodeToStream( M, Stream );
1408
1409   // If writing to stdout, set binary mode.
1410   if (&llvm::outs() == &Out)
1411     sys::Program::ChangeStdoutToBinary();
1412
1413   // Write the generated bitstream to "Out".
1414   Out.write((char*)&Buffer.front(), Buffer.size());
1415
1416   // Make sure it hits disk now.
1417   Out.flush();
1418 }
1419
1420 /// WriteBitcodeToStream - Write the specified module to the specified output
1421 /// stream.
1422 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1423   // If this is darwin, emit a file header and trailer if needed.
1424   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1425   if (isDarwin)
1426     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1427
1428   // Emit the file header.
1429   Stream.Emit((unsigned)'B', 8);
1430   Stream.Emit((unsigned)'C', 8);
1431   Stream.Emit(0x0, 4);
1432   Stream.Emit(0xC, 4);
1433   Stream.Emit(0xE, 4);
1434   Stream.Emit(0xD, 4);
1435
1436   // Emit the module.
1437   WriteModule(M, Stream);
1438
1439   if (isDarwin)
1440     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1441 }