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   // CONSTANTS_BLOCK abbrev id's.
  40   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  41   CONSTANTS_INTEGER_ABBREV,
  42   CONSTANTS_CE_CAST_Abbrev,
  43   CONSTANTS_NULL_Abbrev,
  44
  45   // FUNCTION_BLOCK abbrev id's.
  46   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  47   FUNCTION_INST_RET_VOID_ABBREV,
  48   FUNCTION_INST_RET_VAL_ABBREV,
  49   FUNCTION_INST_UNREACHABLE_ABBREV
  50 };
  51
  52
  53 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  54   switch (Opcode) {
  55   default: assert(0 && "Unknown cast instruction!");
  56   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  57   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  58   case Instruction::SExt    : return bitc::CAST_SEXT;
  59   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  60   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  61   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  62   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  63   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  64   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  65   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  66   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  67   case Instruction::BitCast : return bitc::CAST_BITCAST;
  68   }
  69 }
  70
  71 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  72   switch (Opcode) {
  73   default: assert(0 && "Unknown binary instruction!");
  74   case Instruction::Add:  return bitc::BINOP_ADD;
  75   case Instruction::Sub:  return bitc::BINOP_SUB;
  76   case Instruction::Mul:  return bitc::BINOP_MUL;
  77   case Instruction::UDiv: return bitc::BINOP_UDIV;
  78   case Instruction::FDiv:
  79   case Instruction::SDiv: return bitc::BINOP_SDIV;
  80   case Instruction::URem: return bitc::BINOP_UREM;
  81   case Instruction::FRem:
  82   case Instruction::SRem: return bitc::BINOP_SREM;
  83   case Instruction::Shl:  return bitc::BINOP_SHL;
  84   case Instruction::LShr: return bitc::BINOP_LSHR;
  85   case Instruction::AShr: return bitc::BINOP_ASHR;
  86   case Instruction::And:  return bitc::BINOP_AND;
  87   case Instruction::Or:   return bitc::BINOP_OR;
  88   case Instruction::Xor:  return bitc::BINOP_XOR;
  89   }
  90 }
  91
  92
  93
  94 static void WriteStringRecord(unsigned Code, const std::string &Str,
  95                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
  96   SmallVector<unsigned, 64> Vals;
  97
  98   // Code: [strchar x N]
  99   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 100     Vals.push_back(Str[i]);
 101
 102   // Emit the finished record.
 103   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 104 }
 105
 106 // Emit information about parameter attributes.
 107 static void WriteParamAttrTable(const ValueEnumerator &VE,
 108                                 BitstreamWriter &Stream) {
 109   const std::vector<const ParamAttrsList*> &Attrs = VE.getParamAttrs();
 110   if (Attrs.empty()) return;
 111
 112   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 113
 114   SmallVector<uint64_t, 64> Record;
 115   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 116     const ParamAttrsList *A = Attrs[i];
 117     for (unsigned op = 0, e = A->size(); op != e; ++op) {
 118       Record.push_back(A->getParamIndex(op));
 119       Record.push_back(A->getParamAttrsAtIndex(op));
 120     }
 121
 122     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 123     Record.clear();
 124   }
 125
 126   Stream.ExitBlock();
 127 }
 128
 129 /// WriteTypeTable - Write out the type table for a module.
 130 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 131   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 132
 133   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 134   SmallVector<uint64_t, 64> TypeVals;
 135
 136   // Abbrev for TYPE_CODE_POINTER.
 137   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 138   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 139   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 140                             Log2_32_Ceil(VE.getTypes().size()+1)));
 141   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 142
 143   // Abbrev for TYPE_CODE_FUNCTION.
 144   Abbv = new BitCodeAbbrev();
 145   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 148                             Log2_32_Ceil(VE.getParamAttrs().size()+1)));
 149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 151                             Log2_32_Ceil(VE.getTypes().size()+1)));
 152   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 153
 154   // Abbrev for TYPE_CODE_STRUCT.
 155   Abbv = new BitCodeAbbrev();
 156   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 160                             Log2_32_Ceil(VE.getTypes().size()+1)));
 161   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 162
 163   // Abbrev for TYPE_CODE_ARRAY.
 164   Abbv = new BitCodeAbbrev();
 165   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 168                             Log2_32_Ceil(VE.getTypes().size()+1)));
 169   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 170
 171   // Emit an entry count so the reader can reserve space.
 172   TypeVals.push_back(TypeList.size());
 173   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 174   TypeVals.clear();
 175
 176   // Loop over all of the types, emitting each in turn.
 177   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 178     const Type *T = TypeList[i].first;
 179     int AbbrevToUse = 0;
 180     unsigned Code = 0;
 181
 182     switch (T->getTypeID()) {
 183     case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID.
 184     default: assert(0 && "Unknown type!");
 185     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 186     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 187     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 188     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 189     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 190     case Type::IntegerTyID:
 191       // INTEGER: [width]
 192       Code = bitc::TYPE_CODE_INTEGER;
 193       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 194       break;
 195     case Type::PointerTyID:
 196       // POINTER: [pointee type]
 197       Code = bitc::TYPE_CODE_POINTER;
 198       TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType()));
 199       AbbrevToUse = PtrAbbrev;
 200       break;
 201
 202     case Type::FunctionTyID: {
 203       const FunctionType *FT = cast<FunctionType>(T);
 204       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 205       Code = bitc::TYPE_CODE_FUNCTION;
 206       TypeVals.push_back(FT->isVarArg());
 207       TypeVals.push_back(VE.getParamAttrID(FT->getParamAttrs()));
 208       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 209       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 210         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 211       AbbrevToUse = FunctionAbbrev;
 212       break;
 213     }
 214     case Type::StructTyID: {
 215       const StructType *ST = cast<StructType>(T);
 216       // STRUCT: [ispacked, eltty x N]
 217       Code = bitc::TYPE_CODE_STRUCT;
 218       TypeVals.push_back(ST->isPacked());
 219       // Output all of the element types.
 220       for (StructType::element_iterator I = ST->element_begin(),
 221            E = ST->element_end(); I != E; ++I)
 222         TypeVals.push_back(VE.getTypeID(*I));
 223       AbbrevToUse = StructAbbrev;
 224       break;
 225     }
 226     case Type::ArrayTyID: {
 227       const ArrayType *AT = cast<ArrayType>(T);
 228       // ARRAY: [numelts, eltty]
 229       Code = bitc::TYPE_CODE_ARRAY;
 230       TypeVals.push_back(AT->getNumElements());
 231       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 232       AbbrevToUse = ArrayAbbrev;
 233       break;
 234     }
 235     case Type::VectorTyID: {
 236       const VectorType *VT = cast<VectorType>(T);
 237       // VECTOR [numelts, eltty]
 238       Code = bitc::TYPE_CODE_VECTOR;
 239       TypeVals.push_back(VT->getNumElements());
 240       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 241       break;
 242     }
 243     }
 244
 245     // Emit the finished record.
 246     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 247     TypeVals.clear();
 248   }
 249
 250   Stream.ExitBlock();
 251 }
 252
 253 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 254   switch (GV->getLinkage()) {
 255   default: assert(0 && "Invalid linkage!");
 256   case GlobalValue::ExternalLinkage:     return 0;
 257   case GlobalValue::WeakLinkage:         return 1;
 258   case GlobalValue::AppendingLinkage:    return 2;
 259   case GlobalValue::InternalLinkage:     return 3;
 260   case GlobalValue::LinkOnceLinkage:     return 4;
 261   case GlobalValue::DLLImportLinkage:    return 5;
 262   case GlobalValue::DLLExportLinkage:    return 6;
 263   case GlobalValue::ExternalWeakLinkage: return 7;
 264   }
 265 }
 266
 267 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 268   switch (GV->getVisibility()) {
 269   default: assert(0 && "Invalid visibility!");
 270   case GlobalValue::DefaultVisibility:   return 0;
 271   case GlobalValue::HiddenVisibility:    return 1;
 272   case GlobalValue::ProtectedVisibility: return 2;
 273   }
 274 }
 275
 276 // Emit top-level description of module, including target triple, inline asm,
 277 // descriptors for global variables, and function prototype info.
 278 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 279                             BitstreamWriter &Stream) {
 280   // Emit the list of dependent libraries for the Module.
 281   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 282     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 283
 284   // Emit various pieces of data attached to a module.
 285   if (!M->getTargetTriple().empty())
 286     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 287                       0/*TODO*/, Stream);
 288   if (!M->getDataLayout().empty())
 289     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 290                       0/*TODO*/, Stream);
 291   if (!M->getModuleInlineAsm().empty())
 292     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 293                       0/*TODO*/, Stream);
 294
 295   // Emit information about sections, computing how many there are.  Also
 296   // compute the maximum alignment value.
 297   std::map<std::string, unsigned> SectionMap;
 298   unsigned MaxAlignment = 0;
 299   unsigned MaxGlobalType = 0;
 300   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 301        GV != E; ++GV) {
 302     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 303     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 304
 305     if (!GV->hasSection()) continue;
 306     // Give section names unique ID's.
 307     unsigned &Entry = SectionMap[GV->getSection()];
 308     if (Entry != 0) continue;
 309     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 310                       0/*TODO*/, Stream);
 311     Entry = SectionMap.size();
 312   }
 313   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 314     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 315     if (!F->hasSection()) continue;
 316     // Give section names unique ID's.
 317     unsigned &Entry = SectionMap[F->getSection()];
 318     if (Entry != 0) continue;
 319     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 320                       0/*TODO*/, Stream);
 321     Entry = SectionMap.size();
 322   }
 323
 324   // Emit abbrev for globals, now that we know # sections and max alignment.
 325   unsigned SimpleGVarAbbrev = 0;
 326   if (!M->global_empty()) {
 327     // Add an abbrev for common globals with no visibility or thread localness.
 328     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 329     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 331                               Log2_32_Ceil(MaxGlobalType+1)));
 332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));      // Linkage.
 335     if (MaxAlignment == 0)                                      // Alignment.
 336       Abbv->Add(BitCodeAbbrevOp(0));
 337     else {
 338       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 339       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 340                                Log2_32_Ceil(MaxEncAlignment+1)));
 341     }
 342     if (SectionMap.empty())                                    // Section.
 343       Abbv->Add(BitCodeAbbrevOp(0));
 344     else
 345       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 346                                Log2_32_Ceil(SectionMap.size()+1)));
 347     // Don't bother emitting vis + thread local.
 348     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 349   }
 350
 351   // Emit the global variable information.
 352   SmallVector<unsigned, 64> Vals;
 353   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 354        GV != E; ++GV) {
 355     unsigned AbbrevToUse = 0;
 356
 357     // GLOBALVAR: [type, isconst, initid,
 358     //             linkage, alignment, section, visibility, threadlocal]
 359     Vals.push_back(VE.getTypeID(GV->getType()));
 360     Vals.push_back(GV->isConstant());
 361     Vals.push_back(GV->isDeclaration() ? 0 :
 362                    (VE.getValueID(GV->getInitializer()) + 1));
 363     Vals.push_back(getEncodedLinkage(GV));
 364     Vals.push_back(Log2_32(GV->getAlignment())+1);
 365     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 366     if (GV->isThreadLocal() ||
 367         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 368       Vals.push_back(getEncodedVisibility(GV));
 369       Vals.push_back(GV->isThreadLocal());
 370     } else {
 371       AbbrevToUse = SimpleGVarAbbrev;
 372     }
 373
 374     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 375     Vals.clear();
 376   }
 377
 378   // Emit the function proto information.
 379   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 380     // FUNCTION:  [type, callingconv, isproto, linkage, alignment, section,
 381     //             visibility]
 382     Vals.push_back(VE.getTypeID(F->getType()));
 383     Vals.push_back(F->getCallingConv());
 384     Vals.push_back(F->isDeclaration());
 385     Vals.push_back(getEncodedLinkage(F));
 386     Vals.push_back(Log2_32(F->getAlignment())+1);
 387     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 388     Vals.push_back(getEncodedVisibility(F));
 389
 390     unsigned AbbrevToUse = 0;
 391     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 392     Vals.clear();
 393   }
 394
 395
 396   // Emit the alias information.
 397   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 398        AI != E; ++AI) {
 399     Vals.push_back(VE.getTypeID(AI->getType()));
 400     Vals.push_back(VE.getValueID(AI->getAliasee()));
 401     Vals.push_back(getEncodedLinkage(AI));
 402     unsigned AbbrevToUse = 0;
 403     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 404     Vals.clear();
 405   }
 406 }
 407
 408
 409 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 410                            const ValueEnumerator &VE,
 411                            BitstreamWriter &Stream, bool isGlobal) {
 412   if (FirstVal == LastVal) return;
 413
 414   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 415
 416   unsigned AggregateAbbrev = 0;
 417   unsigned String8Abbrev = 0;
 418   unsigned CString7Abbrev = 0;
 419   unsigned CString6Abbrev = 0;
 420   // If this is a constant pool for the module, emit module-specific abbrevs.
 421   if (isGlobal) {
 422     // Abbrev for CST_CODE_AGGREGATE.
 423     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 424     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 427     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 428
 429     // Abbrev for CST_CODE_STRING.
 430     Abbv = new BitCodeAbbrev();
 431     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 434     String8Abbrev = Stream.EmitAbbrev(Abbv);
 435     // Abbrev for CST_CODE_CSTRING.
 436     Abbv = new BitCodeAbbrev();
 437     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 440     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 441     // Abbrev for CST_CODE_CSTRING.
 442     Abbv = new BitCodeAbbrev();
 443     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 445     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 446     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 447   }
 448
 449   // FIXME: Install and use abbrevs to reduce size.  Install them globally so
 450   // they don't need to be reemitted for each function body.
 451
 452   SmallVector<uint64_t, 64> Record;
 453
 454   const ValueEnumerator::ValueList &Vals = VE.getValues();
 455   const Type *LastTy = 0;
 456   for (unsigned i = FirstVal; i != LastVal; ++i) {
 457     const Value *V = Vals[i].first;
 458     // If we need to switch types, do so now.
 459     if (V->getType() != LastTy) {
 460       LastTy = V->getType();
 461       Record.push_back(VE.getTypeID(LastTy));
 462       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 463                         CONSTANTS_SETTYPE_ABBREV);
 464       Record.clear();
 465     }
 466
 467     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 468       assert(0 && IA && "FIXME: Inline asm writing unimp!");
 469       continue;
 470     }
 471     const Constant *C = cast<Constant>(V);
 472     unsigned Code = -1U;
 473     unsigned AbbrevToUse = 0;
 474     if (C->isNullValue()) {
 475       Code = bitc::CST_CODE_NULL;
 476     } else if (isa<UndefValue>(C)) {
 477       Code = bitc::CST_CODE_UNDEF;
 478     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 479       if (IV->getBitWidth() <= 64) {
 480         int64_t V = IV->getSExtValue();
 481         if (V >= 0)
 482           Record.push_back(V << 1);
 483         else
 484           Record.push_back((-V << 1) | 1);
 485         Code = bitc::CST_CODE_INTEGER;
 486         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 487       } else {                             // Wide integers, > 64 bits in size.
 488         // We have an arbitrary precision integer value to write whose
 489         // bit width is > 64. However, in canonical unsigned integer
 490         // format it is likely that the high bits are going to be zero.
 491         // So, we only write the number of active words.
 492         unsigned NWords = IV->getValue().getActiveWords();
 493         const uint64_t *RawWords = IV->getValue().getRawData();
 494         for (unsigned i = 0; i != NWords; ++i) {
 495           int64_t V = RawWords[i];
 496           if (V >= 0)
 497             Record.push_back(V << 1);
 498           else
 499             Record.push_back((-V << 1) | 1);
 500         }
 501         Code = bitc::CST_CODE_WIDE_INTEGER;
 502       }
 503     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 504       Code = bitc::CST_CODE_FLOAT;
 505       if (CFP->getType() == Type::FloatTy) {
 506         Record.push_back(FloatToBits((float)CFP->getValue()));
 507       } else {
 508         assert (CFP->getType() == Type::DoubleTy && "Unknown FP type!");
 509         Record.push_back(DoubleToBits((double)CFP->getValue()));
 510       }
 511     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 512       // Emit constant strings specially.
 513       unsigned NumOps = C->getNumOperands();
 514       // If this is a null-terminated string, use the denser CSTRING encoding.
 515       if (C->getOperand(NumOps-1)->isNullValue()) {
 516         Code = bitc::CST_CODE_CSTRING;
 517         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 518       } else {
 519         Code = bitc::CST_CODE_STRING;
 520         AbbrevToUse = String8Abbrev;
 521       }
 522       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 523       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 524       for (unsigned i = 0; i != NumOps; ++i) {
 525         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 526         Record.push_back(V);
 527         isCStr7 &= (V & 128) == 0;
 528         if (isCStrChar6)
 529           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 530       }
 531
 532       if (isCStrChar6)
 533         AbbrevToUse = CString6Abbrev;
 534       else if (isCStr7)
 535         AbbrevToUse = CString7Abbrev;
 536     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 537                isa<ConstantVector>(V)) {
 538       Code = bitc::CST_CODE_AGGREGATE;
 539       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 540         Record.push_back(VE.getValueID(C->getOperand(i)));
 541       AbbrevToUse = AggregateAbbrev;
 542     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 543       switch (CE->getOpcode()) {
 544       default:
 545         if (Instruction::isCast(CE->getOpcode())) {
 546           Code = bitc::CST_CODE_CE_CAST;
 547           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 548           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 549           Record.push_back(VE.getValueID(C->getOperand(0)));
 550           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 551         } else {
 552           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 553           Code = bitc::CST_CODE_CE_BINOP;
 554           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 555           Record.push_back(VE.getValueID(C->getOperand(0)));
 556           Record.push_back(VE.getValueID(C->getOperand(1)));
 557         }
 558         break;
 559       case Instruction::GetElementPtr:
 560         Code = bitc::CST_CODE_CE_GEP;
 561         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 562           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 563           Record.push_back(VE.getValueID(C->getOperand(i)));
 564         }
 565         break;
 566       case Instruction::Select:
 567         Code = bitc::CST_CODE_CE_SELECT;
 568         Record.push_back(VE.getValueID(C->getOperand(0)));
 569         Record.push_back(VE.getValueID(C->getOperand(1)));
 570         Record.push_back(VE.getValueID(C->getOperand(2)));
 571         break;
 572       case Instruction::ExtractElement:
 573         Code = bitc::CST_CODE_CE_EXTRACTELT;
 574         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 575         Record.push_back(VE.getValueID(C->getOperand(0)));
 576         Record.push_back(VE.getValueID(C->getOperand(1)));
 577         break;
 578       case Instruction::InsertElement:
 579         Code = bitc::CST_CODE_CE_INSERTELT;
 580         Record.push_back(VE.getValueID(C->getOperand(0)));
 581         Record.push_back(VE.getValueID(C->getOperand(1)));
 582         Record.push_back(VE.getValueID(C->getOperand(2)));
 583         break;
 584       case Instruction::ShuffleVector:
 585         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 586         Record.push_back(VE.getValueID(C->getOperand(0)));
 587         Record.push_back(VE.getValueID(C->getOperand(1)));
 588         Record.push_back(VE.getValueID(C->getOperand(2)));
 589         break;
 590       case Instruction::ICmp:
 591       case Instruction::FCmp:
 592         Code = bitc::CST_CODE_CE_CMP;
 593         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 594         Record.push_back(VE.getValueID(C->getOperand(0)));
 595         Record.push_back(VE.getValueID(C->getOperand(1)));
 596         Record.push_back(CE->getPredicate());
 597         break;
 598       }
 599     } else {
 600       assert(0 && "Unknown constant!");
 601     }
 602     Stream.EmitRecord(Code, Record, AbbrevToUse);
 603     Record.clear();
 604   }
 605
 606   Stream.ExitBlock();
 607 }
 608
 609 static void WriteModuleConstants(const ValueEnumerator &VE,
 610                                  BitstreamWriter &Stream) {
 611   const ValueEnumerator::ValueList &Vals = VE.getValues();
 612
 613   // Find the first constant to emit, which is the first non-globalvalue value.
 614   // We know globalvalues have been emitted by WriteModuleInfo.
 615   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 616     if (!isa<GlobalValue>(Vals[i].first)) {
 617       WriteConstants(i, Vals.size(), VE, Stream, true);
 618       return;
 619     }
 620   }
 621 }
 622
 623 /// PushValueAndType - The file has to encode both the value and type id for
 624 /// many values, because we need to know what type to create for forward
 625 /// references.  However, most operands are not forward references, so this type
 626 /// field is not needed.
 627 ///
 628 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 629 /// instruction ID, then it is a forward reference, and it also includes the
 630 /// type ID.
 631 static bool PushValueAndType(Value *V, unsigned InstID,
 632                              SmallVector<unsigned, 64> &Vals,
 633                              ValueEnumerator &VE) {
 634   unsigned ValID = VE.getValueID(V);
 635   Vals.push_back(ValID);
 636   if (ValID >= InstID) {
 637     Vals.push_back(VE.getTypeID(V->getType()));
 638     return true;
 639   }
 640   return false;
 641 }
 642
 643 /// WriteInstruction - Emit an instruction to the specified stream.
 644 static void WriteInstruction(const Instruction &I, unsigned InstID,
 645                              ValueEnumerator &VE, BitstreamWriter &Stream,
 646                              SmallVector<unsigned, 64> &Vals) {
 647   unsigned Code = 0;
 648   unsigned AbbrevToUse = 0;
 649   switch (I.getOpcode()) {
 650   default:
 651     if (Instruction::isCast(I.getOpcode())) {
 652       Code = bitc::FUNC_CODE_INST_CAST;
 653       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 654       Vals.push_back(VE.getTypeID(I.getType()));
 655       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 656     } else {
 657       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 658       Code = bitc::FUNC_CODE_INST_BINOP;
 659       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 660       Vals.push_back(VE.getValueID(I.getOperand(1)));
 661       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 662     }
 663     break;
 664
 665   case Instruction::GetElementPtr:
 666     Code = bitc::FUNC_CODE_INST_GEP;
 667     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 668       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 669     break;
 670   case Instruction::Select:
 671     Code = bitc::FUNC_CODE_INST_SELECT;
 672     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 673     Vals.push_back(VE.getValueID(I.getOperand(2)));
 674     Vals.push_back(VE.getValueID(I.getOperand(0)));
 675     break;
 676   case Instruction::ExtractElement:
 677     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 678     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 679     Vals.push_back(VE.getValueID(I.getOperand(1)));
 680     break;
 681   case Instruction::InsertElement:
 682     Code = bitc::FUNC_CODE_INST_INSERTELT;
 683     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 684     Vals.push_back(VE.getValueID(I.getOperand(1)));
 685     Vals.push_back(VE.getValueID(I.getOperand(2)));
 686     break;
 687   case Instruction::ShuffleVector:
 688     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 689     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 690     Vals.push_back(VE.getValueID(I.getOperand(1)));
 691     Vals.push_back(VE.getValueID(I.getOperand(2)));
 692     break;
 693   case Instruction::ICmp:
 694   case Instruction::FCmp:
 695     Code = bitc::FUNC_CODE_INST_CMP;
 696     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 697     Vals.push_back(VE.getValueID(I.getOperand(1)));
 698     Vals.push_back(cast<CmpInst>(I).getPredicate());
 699     break;
 700
 701   case Instruction::Ret:
 702     Code = bitc::FUNC_CODE_INST_RET;
 703     if (!I.getNumOperands())
 704       AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 705     else if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 706       AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 707     break;
 708   case Instruction::Br:
 709     Code = bitc::FUNC_CODE_INST_BR;
 710     Vals.push_back(VE.getValueID(I.getOperand(0)));
 711     if (cast<BranchInst>(I).isConditional()) {
 712       Vals.push_back(VE.getValueID(I.getOperand(1)));
 713       Vals.push_back(VE.getValueID(I.getOperand(2)));
 714     }
 715     break;
 716   case Instruction::Switch:
 717     Code = bitc::FUNC_CODE_INST_SWITCH;
 718     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 719     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 720       Vals.push_back(VE.getValueID(I.getOperand(i)));
 721     break;
 722   case Instruction::Invoke: {
 723     Code = bitc::FUNC_CODE_INST_INVOKE;
 724     Vals.push_back(cast<InvokeInst>(I).getCallingConv());
 725     Vals.push_back(VE.getValueID(I.getOperand(1)));      // normal dest
 726     Vals.push_back(VE.getValueID(I.getOperand(2)));      // unwind dest
 727     PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
 728
 729     // Emit value #'s for the fixed parameters.
 730     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 731     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 732     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 733       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 734
 735     // Emit type/value pairs for varargs params.
 736     if (FTy->isVarArg()) {
 737       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 738            i != e; ++i)
 739         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 740     }
 741     break;
 742   }
 743   case Instruction::Unwind:
 744     Code = bitc::FUNC_CODE_INST_UNWIND;
 745     break;
 746   case Instruction::Unreachable:
 747     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 748     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 749     break;
 750
 751   case Instruction::PHI:
 752     Code = bitc::FUNC_CODE_INST_PHI;
 753     Vals.push_back(VE.getTypeID(I.getType()));
 754     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 755       Vals.push_back(VE.getValueID(I.getOperand(i)));
 756     break;
 757
 758   case Instruction::Malloc:
 759     Code = bitc::FUNC_CODE_INST_MALLOC;
 760     Vals.push_back(VE.getTypeID(I.getType()));
 761     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 762     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 763     break;
 764
 765   case Instruction::Free:
 766     Code = bitc::FUNC_CODE_INST_FREE;
 767     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 768     break;
 769
 770   case Instruction::Alloca:
 771     Code = bitc::FUNC_CODE_INST_ALLOCA;
 772     Vals.push_back(VE.getTypeID(I.getType()));
 773     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 774     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 775     break;
 776
 777   case Instruction::Load:
 778     Code = bitc::FUNC_CODE_INST_LOAD;
 779     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 780       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 781
 782     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 783     Vals.push_back(cast<LoadInst>(I).isVolatile());
 784     break;
 785   case Instruction::Store:
 786     Code = bitc::FUNC_CODE_INST_STORE;
 787     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // val.
 788     Vals.push_back(VE.getValueID(I.getOperand(1)));       // ptr.
 789     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 790     Vals.push_back(cast<StoreInst>(I).isVolatile());
 791     break;
 792   case Instruction::Call: {
 793     Code = bitc::FUNC_CODE_INST_CALL;
 794     Vals.push_back((cast<CallInst>(I).getCallingConv() << 1) |
 795                    cast<CallInst>(I).isTailCall());
 796     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // Callee
 797
 798     // Emit value #'s for the fixed parameters.
 799     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 800     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 801     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 802       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 803
 804     // Emit type/value pairs for varargs params.
 805     if (FTy->isVarArg()) {
 806       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 807       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 808            i != e; ++i)
 809         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 810     }
 811     break;
 812   }
 813   case Instruction::VAArg:
 814     Code = bitc::FUNC_CODE_INST_VAARG;
 815     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 816     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 817     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 818     break;
 819   }
 820
 821   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 822   Vals.clear();
 823 }
 824
 825 // Emit names for globals/functions etc.
 826 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 827                                   const ValueEnumerator &VE,
 828                                   BitstreamWriter &Stream) {
 829   if (VST.empty()) return;
 830   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 831
 832   // FIXME: Set up the abbrev, we know how many values there are!
 833   // FIXME: We know if the type names can use 7-bit ascii.
 834   SmallVector<unsigned, 64> NameVals;
 835
 836   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 837        SI != SE; ++SI) {
 838
 839     const ValueName &Name = *SI;
 840
 841     // Figure out the encoding to use for the name.
 842     bool is7Bit = true;
 843     bool isChar6 = true;
 844     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 845          C != E; ++C) {
 846       if (isChar6)
 847         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 848       if ((unsigned char)*C & 128) {
 849         is7Bit = false;
 850         break;  // don't bother scanning the rest.
 851       }
 852     }
 853
 854     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 855
 856     // VST_ENTRY:   [valueid, namechar x N]
 857     // VST_BBENTRY: [bbid, namechar x N]
 858     unsigned Code;
 859     if (isa<BasicBlock>(SI->getValue())) {
 860       Code = bitc::VST_CODE_BBENTRY;
 861       if (isChar6)
 862         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 863     } else {
 864       Code = bitc::VST_CODE_ENTRY;
 865       if (isChar6)
 866         AbbrevToUse = VST_ENTRY_6_ABBREV;
 867       else if (is7Bit)
 868         AbbrevToUse = VST_ENTRY_7_ABBREV;
 869     }
 870
 871     NameVals.push_back(VE.getValueID(SI->getValue()));
 872     for (const char *P = Name.getKeyData(),
 873          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 874       NameVals.push_back((unsigned char)*P);
 875
 876     // Emit the finished record.
 877     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 878     NameVals.clear();
 879   }
 880   Stream.ExitBlock();
 881 }
 882
 883 /// WriteFunction - Emit a function body to the module stream.
 884 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 885                           BitstreamWriter &Stream) {
 886   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 3);
 887   VE.incorporateFunction(F);
 888
 889   SmallVector<unsigned, 64> Vals;
 890
 891   // Emit the number of basic blocks, so the reader can create them ahead of
 892   // time.
 893   Vals.push_back(VE.getBasicBlocks().size());
 894   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
 895   Vals.clear();
 896
 897   // FIXME: Function attributes?
 898
 899   // If there are function-local constants, emit them now.
 900   unsigned CstStart, CstEnd;
 901   VE.getFunctionConstantRange(CstStart, CstEnd);
 902   WriteConstants(CstStart, CstEnd, VE, Stream, false);
 903
 904   // Keep a running idea of what the instruction ID is.
 905   unsigned InstID = CstEnd;
 906
 907   // Finally, emit all the instructions, in order.
 908   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 909     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 910          I != E; ++I) {
 911       WriteInstruction(*I, InstID, VE, Stream, Vals);
 912       if (I->getType() != Type::VoidTy)
 913         ++InstID;
 914     }
 915
 916   // Emit names for all the instructions etc.
 917   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
 918
 919   VE.purgeFunction();
 920   Stream.ExitBlock();
 921 }
 922
 923 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
 924 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
 925                                  const ValueEnumerator &VE,
 926                                  BitstreamWriter &Stream) {
 927   if (TST.empty()) return;
 928
 929   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
 930
 931   // 7-bit fixed width VST_CODE_ENTRY strings.
 932   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 933   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 935                             Log2_32_Ceil(VE.getTypes().size()+1)));
 936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 938   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
 939
 940   SmallVector<unsigned, 64> NameVals;
 941
 942   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
 943        TI != TE; ++TI) {
 944     // TST_ENTRY: [typeid, namechar x N]
 945     NameVals.push_back(VE.getTypeID(TI->second));
 946
 947     const std::string &Str = TI->first;
 948     bool is7Bit = true;
 949     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 950       NameVals.push_back((unsigned char)Str[i]);
 951       if (Str[i] & 128)
 952         is7Bit = false;
 953     }
 954
 955     // Emit the finished record.
 956     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
 957     NameVals.clear();
 958   }
 959
 960   Stream.ExitBlock();
 961 }
 962
 963 // Emit blockinfo, which defines the standard abbreviations etc.
 964 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 965   // We only want to emit block info records for blocks that have multiple
 966   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
 967   // blocks can defined their abbrevs inline.
 968   Stream.EnterBlockInfoBlock(2);
 969
 970   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
 971     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 972     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
 973     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 974     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 975     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 976     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 977                                    Abbv) != VST_ENTRY_8_ABBREV)
 978       assert(0 && "Unexpected abbrev ordering!");
 979   }
 980
 981   { // 7-bit fixed width VST_ENTRY strings.
 982     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 983     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 984     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 985     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 986     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 987     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 988                                    Abbv) != VST_ENTRY_7_ABBREV)
 989       assert(0 && "Unexpected abbrev ordering!");
 990   }
 991   { // 6-bit char6 VST_ENTRY strings.
 992     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 993     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
 994     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 995     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 996     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 997     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
 998                                    Abbv) != VST_ENTRY_6_ABBREV)
 999       assert(0 && "Unexpected abbrev ordering!");
1000   }
1001   { // 6-bit char6 VST_BBENTRY strings.
1002     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1003     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1004     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1005     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1006     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1007     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1008                                    Abbv) != VST_BBENTRY_6_ABBREV)
1009       assert(0 && "Unexpected abbrev ordering!");
1010   }
1011
1012
1013
1014   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1015     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1016     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1017     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1018                               Log2_32_Ceil(VE.getTypes().size()+1)));
1019     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1020                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1021       assert(0 && "Unexpected abbrev ordering!");
1022   }
1023
1024   { // INTEGER abbrev for CONSTANTS_BLOCK.
1025     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1026     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1027     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1028     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1029                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1030       assert(0 && "Unexpected abbrev ordering!");
1031   }
1032
1033   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1034     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1035     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1036     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1037     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1038                               Log2_32_Ceil(VE.getTypes().size()+1)));
1039     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1040
1041     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1042                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1043       assert(0 && "Unexpected abbrev ordering!");
1044   }
1045   { // NULL abbrev for CONSTANTS_BLOCK.
1046     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1047     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1048     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1049                                    Abbv) != CONSTANTS_NULL_Abbrev)
1050       assert(0 && "Unexpected abbrev ordering!");
1051   }
1052
1053   // FIXME: This should only use space for first class types!
1054
1055   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1056     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1057     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1058     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1059     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1060     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1061     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1062                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1063       assert(0 && "Unexpected abbrev ordering!");
1064   }
1065   { // INST_RET abbrev for FUNCTION_BLOCK.
1066     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1067     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1068     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1069                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1070       assert(0 && "Unexpected abbrev ordering!");
1071   }
1072   { // INST_RET abbrev for FUNCTION_BLOCK.
1073     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1074     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1075     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1076     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1077                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1078       assert(0 && "Unexpected abbrev ordering!");
1079   }
1080   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1081     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1082     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1083     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1084                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1085       assert(0 && "Unexpected abbrev ordering!");
1086   }
1087
1088   Stream.ExitBlock();
1089 }
1090
1091
1092 /// WriteModule - Emit the specified module to the bitstream.
1093 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1094   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1095
1096   // Emit the version number if it is non-zero.
1097   if (CurVersion) {
1098     SmallVector<unsigned, 1> Vals;
1099     Vals.push_back(CurVersion);
1100     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1101   }
1102
1103   // Analyze the module, enumerating globals, functions, etc.
1104   ValueEnumerator VE(M);
1105
1106   // Emit blockinfo, which defines the standard abbreviations etc.
1107   WriteBlockInfo(VE, Stream);
1108
1109   // Emit information about parameter attributes.
1110   WriteParamAttrTable(VE, Stream);
1111
1112   // Emit information describing all of the types in the module.
1113   WriteTypeTable(VE, Stream);
1114
1115   // Emit top-level description of module, including target triple, inline asm,
1116   // descriptors for global variables, and function prototype info.
1117   WriteModuleInfo(M, VE, Stream);
1118
1119   // Emit constants.
1120   WriteModuleConstants(VE, Stream);
1121
1122   // If we have any aggregate values in the value table, purge them - these can
1123   // only be used to initialize global variables.  Doing so makes the value
1124   // namespace smaller for code in functions.
1125   int NumNonAggregates = VE.PurgeAggregateValues();
1126   if (NumNonAggregates != -1) {
1127     SmallVector<unsigned, 1> Vals;
1128     Vals.push_back(NumNonAggregates);
1129     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1130   }
1131
1132   // Emit function bodies.
1133   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1134     if (!I->isDeclaration())
1135       WriteFunction(*I, VE, Stream);
1136
1137   // Emit the type symbol table information.
1138   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1139
1140   // Emit names for globals/functions etc.
1141   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1142
1143   Stream.ExitBlock();
1144 }
1145
1146
1147 /// WriteBitcodeToFile - Write the specified module to the specified output
1148 /// stream.
1149 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1150   std::vector<unsigned char> Buffer;
1151   BitstreamWriter Stream(Buffer);
1152
1153   Buffer.reserve(256*1024);
1154
1155   // Emit the file header.
1156   Stream.Emit((unsigned)'B', 8);
1157   Stream.Emit((unsigned)'C', 8);
1158   Stream.Emit(0x0, 4);
1159   Stream.Emit(0xC, 4);
1160   Stream.Emit(0xE, 4);
1161   Stream.Emit(0xD, 4);
1162
1163   // Emit the module.
1164   WriteModule(M, Stream);
1165
1166   // Write the generated bitstream to "Out".
1167   Out.write((char*)&Buffer.front(), Buffer.size());
1168 }