lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by Chris Lattner and is distributed under
   6 // the University of Illinois Open Source 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/Instructions.h"
  21 #include "llvm/Module.h"
  22 #include "llvm/ParameterAttributes.h"
  23 #include "llvm/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 using namespace llvm;
  27
  28 /// These are manifest constants used by the bitcode writer. They do not need to
  29 /// be kept in sync with the reader, but need to be consistent within this file.
  30 enum {
  31   CurVersion = 0,
  32
  33   // VALUE_SYMTAB_BLOCK abbrev id's.
  34   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  35   VST_ENTRY_7_ABBREV,
  36   VST_ENTRY_6_ABBREV,
  37   VST_BBENTRY_6_ABBREV
  38 };
  39
  40
  41 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  42   switch (Opcode) {
  43   default: assert(0 && "Unknown cast instruction!");
  44   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  45   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  46   case Instruction::SExt    : return bitc::CAST_SEXT;
  47   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  48   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  49   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  50   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  51   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  52   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  53   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  54   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  55   case Instruction::BitCast : return bitc::CAST_BITCAST;
  56   }
  57 }
  58
  59 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  60   switch (Opcode) {
  61   default: assert(0 && "Unknown binary instruction!");
  62   case Instruction::Add:  return bitc::BINOP_ADD;
  63   case Instruction::Sub:  return bitc::BINOP_SUB;
  64   case Instruction::Mul:  return bitc::BINOP_MUL;
  65   case Instruction::UDiv: return bitc::BINOP_UDIV;
  66   case Instruction::FDiv:
  67   case Instruction::SDiv: return bitc::BINOP_SDIV;
  68   case Instruction::URem: return bitc::BINOP_UREM;
  69   case Instruction::FRem:
  70   case Instruction::SRem: return bitc::BINOP_SREM;
  71   case Instruction::Shl:  return bitc::BINOP_SHL;
  72   case Instruction::LShr: return bitc::BINOP_LSHR;
  73   case Instruction::AShr: return bitc::BINOP_ASHR;
  74   case Instruction::And:  return bitc::BINOP_AND;
  75   case Instruction::Or:   return bitc::BINOP_OR;
  76   case Instruction::Xor:  return bitc::BINOP_XOR;
  77   }
  78 }
  79
  80
  81
  82 static void WriteStringRecord(unsigned Code, const std::string &Str,
  83                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
  84   SmallVector<unsigned, 64> Vals;
  85
  86   // Code: [strchar x N]
  87   for (unsigned i = 0, e = Str.size(); i != e; ++i)
  88     Vals.push_back(Str[i]);
  89
  90   // Emit the finished record.
  91   Stream.EmitRecord(Code, Vals, AbbrevToUse);
  92 }
  93
  94 // Emit information about parameter attributes.
  95 static void WriteParamAttrTable(const ValueEnumerator &VE,
  96                                 BitstreamWriter &Stream) {
  97   const std::vector<const ParamAttrsList*> &Attrs = VE.getParamAttrs();
  98   if (Attrs.empty()) return;
  99
 100   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 101
 102   SmallVector<uint64_t, 64> Record;
 103   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 104     const ParamAttrsList *A = Attrs[i];
 105     for (unsigned op = 0, e = A->size(); op != e; ++op) {
 106       Record.push_back(A->getParamIndex(op));
 107       Record.push_back(A->getParamAttrsAtIndex(op));
 108     }
 109
 110     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 111     Record.clear();
 112   }
 113
 114   Stream.ExitBlock();
 115 }
 116
 117 /// WriteTypeTable - Write out the type table for a module.
 118 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 119   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 120
 121   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 122   SmallVector<uint64_t, 64> TypeVals;
 123
 124   // Abbrev for TYPE_CODE_POINTER.
 125   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 126   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 128                             Log2_32_Ceil(VE.getTypes().size()+1)));
 129   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 130
 131   // Abbrev for TYPE_CODE_FUNCTION.
 132   Abbv = new BitCodeAbbrev();
 133   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 136                             Log2_32_Ceil(VE.getParamAttrs().size()+1)));
 137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 139                             Log2_32_Ceil(VE.getTypes().size()+1)));
 140   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 141
 142   // Abbrev for TYPE_CODE_STRUCT.
 143   Abbv = new BitCodeAbbrev();
 144   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 148                             Log2_32_Ceil(VE.getTypes().size()+1)));
 149   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 150
 151   // Abbrev for TYPE_CODE_ARRAY.
 152   Abbv = new BitCodeAbbrev();
 153   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 156                             Log2_32_Ceil(VE.getTypes().size()+1)));
 157   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 158
 159   // Emit an entry count so the reader can reserve space.
 160   TypeVals.push_back(TypeList.size());
 161   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 162   TypeVals.clear();
 163
 164   // Loop over all of the types, emitting each in turn.
 165   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 166     const Type *T = TypeList[i].first;
 167     int AbbrevToUse = 0;
 168     unsigned Code = 0;
 169
 170     switch (T->getTypeID()) {
 171     case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID.
 172     default: assert(0 && "Unknown type!");
 173     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 174     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 175     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 176     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 177     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 178     case Type::IntegerTyID:
 179       // INTEGER: [width]
 180       Code = bitc::TYPE_CODE_INTEGER;
 181       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 182       break;
 183     case Type::PointerTyID:
 184       // POINTER: [pointee type]
 185       Code = bitc::TYPE_CODE_POINTER;
 186       TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType()));
 187       AbbrevToUse = PtrAbbrev;
 188       break;
 189
 190     case Type::FunctionTyID: {
 191       const FunctionType *FT = cast<FunctionType>(T);
 192       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 193       Code = bitc::TYPE_CODE_FUNCTION;
 194       TypeVals.push_back(FT->isVarArg());
 195       TypeVals.push_back(VE.getParamAttrID(FT->getParamAttrs()));
 196       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 197       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 198         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 199       AbbrevToUse = FunctionAbbrev;
 200       break;
 201     }
 202     case Type::StructTyID: {
 203       const StructType *ST = cast<StructType>(T);
 204       // STRUCT: [ispacked, eltty x N]
 205       Code = bitc::TYPE_CODE_STRUCT;
 206       TypeVals.push_back(ST->isPacked());
 207       // Output all of the element types.
 208       for (StructType::element_iterator I = ST->element_begin(),
 209            E = ST->element_end(); I != E; ++I)
 210         TypeVals.push_back(VE.getTypeID(*I));
 211       AbbrevToUse = StructAbbrev;
 212       break;
 213     }
 214     case Type::ArrayTyID: {
 215       const ArrayType *AT = cast<ArrayType>(T);
 216       // ARRAY: [numelts, eltty]
 217       Code = bitc::TYPE_CODE_ARRAY;
 218       TypeVals.push_back(AT->getNumElements());
 219       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 220       AbbrevToUse = ArrayAbbrev;
 221       break;
 222     }
 223     case Type::VectorTyID: {
 224       const VectorType *VT = cast<VectorType>(T);
 225       // VECTOR [numelts, eltty]
 226       Code = bitc::TYPE_CODE_VECTOR;
 227       TypeVals.push_back(VT->getNumElements());
 228       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 229       break;
 230     }
 231     }
 232
 233     // Emit the finished record.
 234     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 235     TypeVals.clear();
 236   }
 237
 238   Stream.ExitBlock();
 239 }
 240
 241 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 242   switch (GV->getLinkage()) {
 243   default: assert(0 && "Invalid linkage!");
 244   case GlobalValue::ExternalLinkage:     return 0;
 245   case GlobalValue::WeakLinkage:         return 1;
 246   case GlobalValue::AppendingLinkage:    return 2;
 247   case GlobalValue::InternalLinkage:     return 3;
 248   case GlobalValue::LinkOnceLinkage:     return 4;
 249   case GlobalValue::DLLImportLinkage:    return 5;
 250   case GlobalValue::DLLExportLinkage:    return 6;
 251   case GlobalValue::ExternalWeakLinkage: return 7;
 252   }
 253 }
 254
 255 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 256   switch (GV->getVisibility()) {
 257   default: assert(0 && "Invalid visibility!");
 258   case GlobalValue::DefaultVisibility:   return 0;
 259   case GlobalValue::HiddenVisibility:    return 1;
 260   case GlobalValue::ProtectedVisibility: return 2;
 261   }
 262 }
 263
 264 // Emit top-level description of module, including target triple, inline asm,
 265 // descriptors for global variables, and function prototype info.
 266 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 267                             BitstreamWriter &Stream) {
 268   // Emit the list of dependent libraries for the Module.
 269   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 270     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 271
 272   // Emit various pieces of data attached to a module.
 273   if (!M->getTargetTriple().empty())
 274     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 275                       0/*TODO*/, Stream);
 276   if (!M->getDataLayout().empty())
 277     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 278                       0/*TODO*/, Stream);
 279   if (!M->getModuleInlineAsm().empty())
 280     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 281                       0/*TODO*/, Stream);
 282
 283   // Emit information about sections, computing how many there are.  Also
 284   // compute the maximum alignment value.
 285   std::map<std::string, unsigned> SectionMap;
 286   unsigned MaxAlignment = 0;
 287   unsigned MaxGlobalType = 0;
 288   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 289        GV != E; ++GV) {
 290     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 291     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 292
 293     if (!GV->hasSection()) continue;
 294     // Give section names unique ID's.
 295     unsigned &Entry = SectionMap[GV->getSection()];
 296     if (Entry != 0) continue;
 297     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 298                       0/*TODO*/, Stream);
 299     Entry = SectionMap.size();
 300   }
 301   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 302     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 303     if (!F->hasSection()) continue;
 304     // Give section names unique ID's.
 305     unsigned &Entry = SectionMap[F->getSection()];
 306     if (Entry != 0) continue;
 307     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 308                       0/*TODO*/, Stream);
 309     Entry = SectionMap.size();
 310   }
 311
 312   // Emit abbrev for globals, now that we know # sections and max alignment.
 313   unsigned SimpleGVarAbbrev = 0;
 314   if (!M->global_empty()) {
 315     // Add an abbrev for common globals with no visibility or thread localness.
 316     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 317     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 319                               Log2_32_Ceil(MaxGlobalType+1)));
 320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));      // Linkage.
 323     if (MaxAlignment == 0)                                      // Alignment.
 324       Abbv->Add(BitCodeAbbrevOp(0));
 325     else {
 326       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 327       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 328                                Log2_32_Ceil(MaxEncAlignment+1)));
 329     }
 330     if (SectionMap.empty())                                    // Section.
 331       Abbv->Add(BitCodeAbbrevOp(0));
 332     else
 333       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 334                                Log2_32_Ceil(SectionMap.size()+1)));
 335     // Don't bother emitting vis + thread local.
 336     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 337   }
 338
 339   // Emit the global variable information.
 340   SmallVector<unsigned, 64> Vals;
 341   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 342        GV != E; ++GV) {
 343     unsigned AbbrevToUse = 0;
 344
 345     // GLOBALVAR: [type, isconst, initid,
 346     //             linkage, alignment, section, visibility, threadlocal]
 347     Vals.push_back(VE.getTypeID(GV->getType()));
 348     Vals.push_back(GV->isConstant());
 349     Vals.push_back(GV->isDeclaration() ? 0 :
 350                    (VE.getValueID(GV->getInitializer()) + 1));
 351     Vals.push_back(getEncodedLinkage(GV));
 352     Vals.push_back(Log2_32(GV->getAlignment())+1);
 353     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 354     if (GV->isThreadLocal() ||
 355         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 356       Vals.push_back(getEncodedVisibility(GV));
 357       Vals.push_back(GV->isThreadLocal());
 358     } else {
 359       AbbrevToUse = SimpleGVarAbbrev;
 360     }
 361
 362     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 363     Vals.clear();
 364   }
 365
 366   // Emit the function proto information.
 367   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 368     // FUNCTION:  [type, callingconv, isproto, linkage, alignment, section,
 369     //             visibility]
 370     Vals.push_back(VE.getTypeID(F->getType()));
 371     Vals.push_back(F->getCallingConv());
 372     Vals.push_back(F->isDeclaration());
 373     Vals.push_back(getEncodedLinkage(F));
 374     Vals.push_back(Log2_32(F->getAlignment())+1);
 375     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 376     Vals.push_back(getEncodedVisibility(F));
 377
 378     unsigned AbbrevToUse = 0;
 379     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 380     Vals.clear();
 381   }
 382
 383
 384   // Emit the alias information.
 385   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 386        AI != E; ++AI) {
 387     Vals.push_back(VE.getTypeID(AI->getType()));
 388     Vals.push_back(VE.getValueID(AI->getAliasee()));
 389     Vals.push_back(getEncodedLinkage(AI));
 390     unsigned AbbrevToUse = 0;
 391     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 392     Vals.clear();
 393   }
 394 }
 395
 396
 397 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 398                            const ValueEnumerator &VE,
 399                            BitstreamWriter &Stream) {
 400   if (FirstVal == LastVal) return;
 401
 402   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 2);
 403
 404   // FIXME: Install and use abbrevs to reduce size.  Install them globally so
 405   // they don't need to be reemitted for each function body.
 406
 407   SmallVector<uint64_t, 64> Record;
 408
 409   const ValueEnumerator::ValueList &Vals = VE.getValues();
 410   const Type *LastTy = 0;
 411   for (unsigned i = FirstVal; i != LastVal; ++i) {
 412     const Value *V = Vals[i].first;
 413     // If we need to switch types, do so now.
 414     if (V->getType() != LastTy) {
 415       LastTy = V->getType();
 416       Record.push_back(VE.getTypeID(LastTy));
 417       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record);
 418       Record.clear();
 419     }
 420
 421     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 422       assert(0 && IA && "FIXME: Inline asm writing unimp!");
 423       continue;
 424     }
 425     const Constant *C = cast<Constant>(V);
 426     unsigned Code = -1U;
 427     unsigned AbbrevToUse = 0;
 428     if (C->isNullValue()) {
 429       Code = bitc::CST_CODE_NULL;
 430     } else if (isa<UndefValue>(C)) {
 431       Code = bitc::CST_CODE_UNDEF;
 432     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 433       if (IV->getBitWidth() <= 64) {
 434         int64_t V = IV->getSExtValue();
 435         if (V >= 0)
 436           Record.push_back(V << 1);
 437         else
 438           Record.push_back((-V << 1) | 1);
 439         Code = bitc::CST_CODE_INTEGER;
 440       } else {                             // Wide integers, > 64 bits in size.
 441         // We have an arbitrary precision integer value to write whose
 442         // bit width is > 64. However, in canonical unsigned integer
 443         // format it is likely that the high bits are going to be zero.
 444         // So, we only write the number of active words.
 445         unsigned NWords = IV->getValue().getActiveWords();
 446         const uint64_t *RawWords = IV->getValue().getRawData();
 447         for (unsigned i = 0; i != NWords; ++i) {
 448           int64_t V = RawWords[i];
 449           if (V >= 0)
 450             Record.push_back(V << 1);
 451           else
 452             Record.push_back((-V << 1) | 1);
 453         }
 454         Code = bitc::CST_CODE_WIDE_INTEGER;
 455       }
 456     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 457       Code = bitc::CST_CODE_FLOAT;
 458       if (CFP->getType() == Type::FloatTy) {
 459         Record.push_back(FloatToBits((float)CFP->getValue()));
 460       } else {
 461         assert (CFP->getType() == Type::DoubleTy && "Unknown FP type!");
 462         Record.push_back(DoubleToBits((double)CFP->getValue()));
 463       }
 464     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 465                isa<ConstantVector>(V)) {
 466       Code = bitc::CST_CODE_AGGREGATE;
 467       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 468         Record.push_back(VE.getValueID(C->getOperand(i)));
 469     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 470       switch (CE->getOpcode()) {
 471       default:
 472         if (Instruction::isCast(CE->getOpcode())) {
 473           Code = bitc::CST_CODE_CE_CAST;
 474           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 475           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 476           Record.push_back(VE.getValueID(C->getOperand(0)));
 477         } else {
 478           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 479           Code = bitc::CST_CODE_CE_BINOP;
 480           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 481           Record.push_back(VE.getValueID(C->getOperand(0)));
 482           Record.push_back(VE.getValueID(C->getOperand(1)));
 483         }
 484         break;
 485       case Instruction::GetElementPtr:
 486         Code = bitc::CST_CODE_CE_GEP;
 487         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 488           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 489           Record.push_back(VE.getValueID(C->getOperand(i)));
 490         }
 491         break;
 492       case Instruction::Select:
 493         Code = bitc::CST_CODE_CE_SELECT;
 494         Record.push_back(VE.getValueID(C->getOperand(0)));
 495         Record.push_back(VE.getValueID(C->getOperand(1)));
 496         Record.push_back(VE.getValueID(C->getOperand(2)));
 497         break;
 498       case Instruction::ExtractElement:
 499         Code = bitc::CST_CODE_CE_EXTRACTELT;
 500         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 501         Record.push_back(VE.getValueID(C->getOperand(0)));
 502         Record.push_back(VE.getValueID(C->getOperand(1)));
 503         break;
 504       case Instruction::InsertElement:
 505         Code = bitc::CST_CODE_CE_INSERTELT;
 506         Record.push_back(VE.getValueID(C->getOperand(0)));
 507         Record.push_back(VE.getValueID(C->getOperand(1)));
 508         Record.push_back(VE.getValueID(C->getOperand(2)));
 509         break;
 510       case Instruction::ShuffleVector:
 511         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 512         Record.push_back(VE.getValueID(C->getOperand(0)));
 513         Record.push_back(VE.getValueID(C->getOperand(1)));
 514         Record.push_back(VE.getValueID(C->getOperand(2)));
 515         break;
 516       case Instruction::ICmp:
 517       case Instruction::FCmp:
 518         Code = bitc::CST_CODE_CE_CMP;
 519         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 520         Record.push_back(VE.getValueID(C->getOperand(0)));
 521         Record.push_back(VE.getValueID(C->getOperand(1)));
 522         Record.push_back(CE->getPredicate());
 523         break;
 524       }
 525     } else {
 526       assert(0 && "Unknown constant!");
 527     }
 528     Stream.EmitRecord(Code, Record, AbbrevToUse);
 529     Record.clear();
 530   }
 531
 532   Stream.ExitBlock();
 533 }
 534
 535 static void WriteModuleConstants(const ValueEnumerator &VE,
 536                                  BitstreamWriter &Stream) {
 537   const ValueEnumerator::ValueList &Vals = VE.getValues();
 538
 539   // Find the first constant to emit, which is the first non-globalvalue value.
 540   // We know globalvalues have been emitted by WriteModuleInfo.
 541   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 542     if (!isa<GlobalValue>(Vals[i].first)) {
 543       WriteConstants(i, Vals.size(), VE, Stream);
 544       return;
 545     }
 546   }
 547 }
 548
 549 /// WriteInstruction - Emit an instruction to the specified stream.
 550 static void WriteInstruction(const Instruction &I, ValueEnumerator &VE,
 551                              BitstreamWriter &Stream,
 552                              SmallVector<unsigned, 64> &Vals) {
 553   unsigned Code = 0;
 554   unsigned AbbrevToUse = 0;
 555   switch (I.getOpcode()) {
 556   default:
 557     if (Instruction::isCast(I.getOpcode())) {
 558       Code = bitc::FUNC_CODE_INST_CAST;
 559       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 560       Vals.push_back(VE.getTypeID(I.getType()));
 561       Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 562       Vals.push_back(VE.getValueID(I.getOperand(0)));
 563     } else {
 564       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 565       Code = bitc::FUNC_CODE_INST_BINOP;
 566       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 567       Vals.push_back(VE.getTypeID(I.getType()));
 568       Vals.push_back(VE.getValueID(I.getOperand(0)));
 569       Vals.push_back(VE.getValueID(I.getOperand(1)));
 570     }
 571     break;
 572
 573   case Instruction::GetElementPtr:
 574     Code = bitc::FUNC_CODE_INST_GEP;
 575     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
 576       Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
 577       Vals.push_back(VE.getValueID(I.getOperand(i)));
 578     }
 579     break;
 580   case Instruction::Select:
 581     Code = bitc::FUNC_CODE_INST_SELECT;
 582     Vals.push_back(VE.getTypeID(I.getType()));
 583     Vals.push_back(VE.getValueID(I.getOperand(0)));
 584     Vals.push_back(VE.getValueID(I.getOperand(1)));
 585     Vals.push_back(VE.getValueID(I.getOperand(2)));
 586     break;
 587   case Instruction::ExtractElement:
 588     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 589     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 590     Vals.push_back(VE.getValueID(I.getOperand(0)));
 591     Vals.push_back(VE.getValueID(I.getOperand(1)));
 592     break;
 593   case Instruction::InsertElement:
 594     Code = bitc::FUNC_CODE_INST_INSERTELT;
 595     Vals.push_back(VE.getTypeID(I.getType()));
 596     Vals.push_back(VE.getValueID(I.getOperand(0)));
 597     Vals.push_back(VE.getValueID(I.getOperand(1)));
 598     Vals.push_back(VE.getValueID(I.getOperand(2)));
 599     break;
 600   case Instruction::ShuffleVector:
 601     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 602     Vals.push_back(VE.getTypeID(I.getType()));
 603     Vals.push_back(VE.getValueID(I.getOperand(0)));
 604     Vals.push_back(VE.getValueID(I.getOperand(1)));
 605     Vals.push_back(VE.getValueID(I.getOperand(2)));
 606     break;
 607   case Instruction::ICmp:
 608   case Instruction::FCmp:
 609     Code = bitc::FUNC_CODE_INST_CMP;
 610     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 611     Vals.push_back(VE.getValueID(I.getOperand(0)));
 612     Vals.push_back(VE.getValueID(I.getOperand(1)));
 613     Vals.push_back(cast<CmpInst>(I).getPredicate());
 614     break;
 615
 616   case Instruction::Ret:
 617     Code = bitc::FUNC_CODE_INST_RET;
 618     if (I.getNumOperands()) {
 619       Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 620       Vals.push_back(VE.getValueID(I.getOperand(0)));
 621     }
 622     break;
 623   case Instruction::Br:
 624     Code = bitc::FUNC_CODE_INST_BR;
 625     Vals.push_back(VE.getValueID(I.getOperand(0)));
 626     if (cast<BranchInst>(I).isConditional()) {
 627       Vals.push_back(VE.getValueID(I.getOperand(1)));
 628       Vals.push_back(VE.getValueID(I.getOperand(2)));
 629     }
 630     break;
 631   case Instruction::Switch:
 632     Code = bitc::FUNC_CODE_INST_SWITCH;
 633     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 634     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 635       Vals.push_back(VE.getValueID(I.getOperand(i)));
 636     break;
 637   case Instruction::Invoke: {
 638     Code = bitc::FUNC_CODE_INST_INVOKE;
 639     Vals.push_back(cast<InvokeInst>(I).getCallingConv());
 640     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 641     Vals.push_back(VE.getValueID(I.getOperand(0)));  // callee
 642     Vals.push_back(VE.getValueID(I.getOperand(1)));  // normal
 643     Vals.push_back(VE.getValueID(I.getOperand(2)));  // unwind
 644
 645     // Emit value #'s for the fixed parameters.
 646     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 647     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 648     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 649       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 650
 651     // Emit type/value pairs for varargs params.
 652     if (FTy->isVarArg()) {
 653       unsigned NumVarargs = I.getNumOperands()-3-FTy->getNumParams();
 654       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 655            i != e; ++i) {
 656         Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
 657         Vals.push_back(VE.getValueID(I.getOperand(i)));
 658       }
 659     }
 660     break;
 661   }
 662   case Instruction::Unwind:
 663     Code = bitc::FUNC_CODE_INST_UNWIND;
 664     break;
 665   case Instruction::Unreachable:
 666     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 667     break;
 668
 669   case Instruction::PHI:
 670     Code = bitc::FUNC_CODE_INST_PHI;
 671     Vals.push_back(VE.getTypeID(I.getType()));
 672     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 673       Vals.push_back(VE.getValueID(I.getOperand(i)));
 674     break;
 675
 676   case Instruction::Malloc:
 677     Code = bitc::FUNC_CODE_INST_MALLOC;
 678     Vals.push_back(VE.getTypeID(I.getType()));
 679     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 680     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 681     break;
 682
 683   case Instruction::Free:
 684     Code = bitc::FUNC_CODE_INST_FREE;
 685     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 686     Vals.push_back(VE.getValueID(I.getOperand(0)));
 687     break;
 688
 689   case Instruction::Alloca:
 690     Code = bitc::FUNC_CODE_INST_ALLOCA;
 691     Vals.push_back(VE.getTypeID(I.getType()));
 692     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 693     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 694     break;
 695
 696   case Instruction::Load:
 697     Code = bitc::FUNC_CODE_INST_LOAD;
 698     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 699     Vals.push_back(VE.getValueID(I.getOperand(0))); // ptr.
 700     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 701     Vals.push_back(cast<LoadInst>(I).isVolatile());
 702     break;
 703   case Instruction::Store:
 704     Code = bitc::FUNC_CODE_INST_STORE;
 705     Vals.push_back(VE.getTypeID(I.getOperand(1)->getType()));   // Pointer
 706     Vals.push_back(VE.getValueID(I.getOperand(0))); // val.
 707     Vals.push_back(VE.getValueID(I.getOperand(1))); // ptr.
 708     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 709     Vals.push_back(cast<StoreInst>(I).isVolatile());
 710     break;
 711   case Instruction::Call: {
 712     Code = bitc::FUNC_CODE_INST_CALL;
 713     Vals.push_back((cast<CallInst>(I).getCallingConv() << 1) |
 714                    cast<CallInst>(I).isTailCall());
 715     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 716     Vals.push_back(VE.getValueID(I.getOperand(0)));  // callee
 717
 718     // Emit value #'s for the fixed parameters.
 719     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 720     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 721     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 722       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 723
 724     // Emit type/value pairs for varargs params.
 725     if (FTy->isVarArg()) {
 726       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 727       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 728            i != e; ++i) {
 729         Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
 730         Vals.push_back(VE.getValueID(I.getOperand(i)));
 731       }
 732     }
 733     break;
 734   }
 735   case Instruction::VAArg:
 736     Code = bitc::FUNC_CODE_INST_VAARG;
 737     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 738     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 739     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 740     break;
 741   }
 742
 743   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 744   Vals.clear();
 745 }
 746
 747 // Emit names for globals/functions etc.
 748 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 749                                   const ValueEnumerator &VE,
 750                                   BitstreamWriter &Stream) {
 751   if (VST.empty()) return;
 752   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 753
 754   // FIXME: Set up the abbrev, we know how many values there are!
 755   // FIXME: We know if the type names can use 7-bit ascii.
 756   SmallVector<unsigned, 64> NameVals;
 757
 758   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 759        SI != SE; ++SI) {
 760
 761     const ValueName &Name = *SI;
 762
 763     // Figure out the encoding to use for the name.
 764     bool is7Bit = true;
 765     bool isChar6 = true;
 766     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 767          C != E; ++C) {
 768       if (isChar6)
 769         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 770       if ((unsigned char)*C & 128) {
 771         is7Bit = false;
 772         break;  // don't bother scanning the rest.
 773       }
 774     }
 775
 776     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 777
 778     // VST_ENTRY:   [valueid, namechar x N]
 779     // VST_BBENTRY: [bbid, namechar x N]
 780     unsigned Code;
 781     if (isa<BasicBlock>(SI->getValue())) {
 782       Code = bitc::VST_CODE_BBENTRY;
 783       if (isChar6)
 784         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 785     } else {
 786       Code = bitc::VST_CODE_ENTRY;
 787       if (isChar6)
 788         AbbrevToUse = VST_ENTRY_6_ABBREV;
 789       else if (is7Bit)
 790         AbbrevToUse = VST_ENTRY_7_ABBREV;
 791     }
 792
 793     NameVals.push_back(VE.getValueID(SI->getValue()));
 794     for (const char *P = Name.getKeyData(),
 795          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 796       NameVals.push_back((unsigned char)*P);
 797
 798     // Emit the finished record.
 799     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 800     NameVals.clear();
 801   }
 802   Stream.ExitBlock();
 803 }
 804
 805 /// WriteFunction - Emit a function body to the module stream.
 806 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 807                           BitstreamWriter &Stream) {
 808   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 3);
 809   VE.incorporateFunction(F);
 810
 811   SmallVector<unsigned, 64> Vals;
 812
 813   // Emit the number of basic blocks, so the reader can create them ahead of
 814   // time.
 815   Vals.push_back(VE.getBasicBlocks().size());
 816   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
 817   Vals.clear();
 818
 819   // FIXME: Function attributes?
 820
 821   // If there are function-local constants, emit them now.
 822   unsigned CstStart, CstEnd;
 823   VE.getFunctionConstantRange(CstStart, CstEnd);
 824   WriteConstants(CstStart, CstEnd, VE, Stream);
 825
 826   // Finally, emit all the instructions, in order.
 827   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 828     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
 829       WriteInstruction(*I, VE, Stream, Vals);
 830
 831   // Emit names for all the instructions etc.
 832   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
 833
 834   VE.purgeFunction();
 835   Stream.ExitBlock();
 836 }
 837
 838 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
 839 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
 840                                  const ValueEnumerator &VE,
 841                                  BitstreamWriter &Stream) {
 842   if (TST.empty()) return;
 843
 844   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
 845
 846   // 7-bit fixed width VST_CODE_ENTRY strings.
 847   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 848   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 850                             Log2_32_Ceil(VE.getTypes().size()+1)));
 851   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 852   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 853   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
 854
 855   SmallVector<unsigned, 64> NameVals;
 856
 857   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
 858        TI != TE; ++TI) {
 859     // TST_ENTRY: [typeid, namechar x N]
 860     NameVals.push_back(VE.getTypeID(TI->second));
 861
 862     const std::string &Str = TI->first;
 863     bool is7Bit = true;
 864     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 865       NameVals.push_back((unsigned char)Str[i]);
 866       if (Str[i] & 128)
 867         is7Bit = false;
 868     }
 869
 870     // Emit the finished record.
 871     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
 872     NameVals.clear();
 873   }
 874
 875   Stream.ExitBlock();
 876 }
 877
 878
 879 /// WriteModule - Emit the specified module to the bitstream.
 880 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
 881   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
 882
 883   // Emit the version number if it is non-zero.
 884   if (CurVersion) {
 885     SmallVector<unsigned, 1> Vals;
 886     Vals.push_back(CurVersion);
 887     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
 888   }
 889
 890   // Analyze the module, enumerating globals, functions, etc.
 891   ValueEnumerator VE(M);
 892
 893   // Emit information about parameter attributes.
 894   WriteParamAttrTable(VE, Stream);
 895
 896   // Emit information describing all of the types in the module.
 897   WriteTypeTable(VE, Stream);
 898
 899   // Emit top-level description of module, including target triple, inline asm,
 900   // descriptors for global variables, and function prototype info.
 901   WriteModuleInfo(M, VE, Stream);
 902
 903   // Emit constants.
 904   WriteModuleConstants(VE, Stream);
 905
 906   // If we have any aggregate values in the value table, purge them - these can
 907   // only be used to initialize global variables.  Doing so makes the value
 908   // namespace smaller for code in functions.
 909   int NumNonAggregates = VE.PurgeAggregateValues();
 910   if (NumNonAggregates != -1) {
 911     SmallVector<unsigned, 1> Vals;
 912     Vals.push_back(NumNonAggregates);
 913     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
 914   }
 915
 916   // Emit function bodies.
 917   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
 918     if (!I->isDeclaration())
 919       WriteFunction(*I, VE, Stream);
 920
 921   // Emit the type symbol table information.
 922   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
 923
 924   // Emit names for globals/functions etc.
 925   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
 926
 927   Stream.ExitBlock();
 928 }
 929
 930 // Emit blockinfo, which defines the standard abbreviations etc.
 931 static void WriteBlockInfo(BitstreamWriter &Stream) {
 932   // We only want to emit block info records for blocks that have multiple
 933   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
 934   // blocks can defined their abbrevs inline.
 935   Stream.EnterBlockInfoBlock(2);
 936
 937   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
 938     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 939     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
 940     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 941     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 942     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 943     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 944                                    Abbv) != VST_ENTRY_8_ABBREV)
 945       assert(0 && "Unexpected abbrev ordering!");
 946   }
 947
 948   { // 7-bit fixed width VST_ENTRY strings.
 949     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 950     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 951     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 952     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 953     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 954     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 955                                    Abbv) != VST_ENTRY_7_ABBREV)
 956       assert(0 && "Unexpected abbrev ordering!");
 957   }
 958   { // 6-bit char6 VST_ENTRY strings.
 959     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 960     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 961     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 962     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 963     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 964     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 965                                    Abbv) != VST_ENTRY_6_ABBREV)
 966       assert(0 && "Unexpected abbrev ordering!");
 967   }
 968   { // 6-bit char6 VST_BBENTRY strings.
 969     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 970     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
 971     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 972     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 973     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 974     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 975                                    Abbv) != VST_BBENTRY_6_ABBREV)
 976       assert(0 && "Unexpected abbrev ordering!");
 977   }
 978
 979   Stream.ExitBlock();
 980 }
 981
 982
 983 /// WriteBitcodeToFile - Write the specified module to the specified output
 984 /// stream.
 985 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
 986   std::vector<unsigned char> Buffer;
 987   BitstreamWriter Stream(Buffer);
 988
 989   Buffer.reserve(256*1024);
 990
 991   // Emit the file header.
 992   Stream.Emit((unsigned)'B', 8);
 993   Stream.Emit((unsigned)'C', 8);
 994   Stream.Emit(0x0, 4);
 995   Stream.Emit(0xC, 4);
 996   Stream.Emit(0xE, 4);
 997   Stream.Emit(0xD, 4);
 998
 999   // Emit blockinfo, which defines the standard abbreviations etc.
1000   WriteBlockInfo(Stream);
1001
1002   // Emit the module.
1003   WriteModule(M, Stream);
1004
1005   // Write the generated bitstream to "Out".
1006   Out.write((char*)&Buffer.front(), Buffer.size());
1007 }