lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include "llvm/System/Program.h"
  29 using namespace llvm;
  30
  31 /// These are manifest constants used by the bitcode writer. They do not need to
  32 /// be kept in sync with the reader, but need to be consistent within this file.
  33 enum {
  34   CurVersion = 0,
  35
  36   // VALUE_SYMTAB_BLOCK abbrev id's.
  37   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  38   VST_ENTRY_7_ABBREV,
  39   VST_ENTRY_6_ABBREV,
  40   VST_BBENTRY_6_ABBREV,
  41
  42   // CONSTANTS_BLOCK abbrev id's.
  43   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  44   CONSTANTS_INTEGER_ABBREV,
  45   CONSTANTS_CE_CAST_Abbrev,
  46   CONSTANTS_NULL_Abbrev,
  47
  48   // FUNCTION_BLOCK abbrev id's.
  49   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  50   FUNCTION_INST_BINOP_ABBREV,
  51   FUNCTION_INST_CAST_ABBREV,
  52   FUNCTION_INST_RET_VOID_ABBREV,
  53   FUNCTION_INST_RET_VAL_ABBREV,
  54   FUNCTION_INST_UNREACHABLE_ABBREV
  55 };
  56
  57
  58 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  59   switch (Opcode) {
  60   default: assert(0 && "Unknown cast instruction!");
  61   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  62   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  63   case Instruction::SExt    : return bitc::CAST_SEXT;
  64   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  65   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  66   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  67   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  68   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  69   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  70   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  71   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  72   case Instruction::BitCast : return bitc::CAST_BITCAST;
  73   }
  74 }
  75
  76 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  77   switch (Opcode) {
  78   default: assert(0 && "Unknown binary instruction!");
  79   case Instruction::Add:  return bitc::BINOP_ADD;
  80   case Instruction::Sub:  return bitc::BINOP_SUB;
  81   case Instruction::Mul:  return bitc::BINOP_MUL;
  82   case Instruction::UDiv: return bitc::BINOP_UDIV;
  83   case Instruction::FDiv:
  84   case Instruction::SDiv: return bitc::BINOP_SDIV;
  85   case Instruction::URem: return bitc::BINOP_UREM;
  86   case Instruction::FRem:
  87   case Instruction::SRem: return bitc::BINOP_SREM;
  88   case Instruction::Shl:  return bitc::BINOP_SHL;
  89   case Instruction::LShr: return bitc::BINOP_LSHR;
  90   case Instruction::AShr: return bitc::BINOP_ASHR;
  91   case Instruction::And:  return bitc::BINOP_AND;
  92   case Instruction::Or:   return bitc::BINOP_OR;
  93   case Instruction::Xor:  return bitc::BINOP_XOR;
  94   }
  95 }
  96
  97
  98
  99 static void WriteStringRecord(unsigned Code, const std::string &Str,
 100                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 101   SmallVector<unsigned, 64> Vals;
 102
 103   // Code: [strchar x N]
 104   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 105     Vals.push_back(Str[i]);
 106
 107   // Emit the finished record.
 108   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 109 }
 110
 111 // Emit information about parameter attributes.
 112 static void WriteAttributeTable(const ValueEnumerator &VE,
 113                                 BitstreamWriter &Stream) {
 114   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 115   if (Attrs.empty()) return;
 116
 117   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 118
 119   SmallVector<uint64_t, 64> Record;
 120   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 121     const AttrListPtr &A = Attrs[i];
 122     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 123       const AttributeWithIndex &PAWI = A.getSlot(i);
 124       Record.push_back(PAWI.Index);
 125
 126       // FIXME: remove in LLVM 3.0
 127       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 128       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 129       // 11 bits.
 130       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 131       if (PAWI.Attrs & Attribute::Alignment)
 132         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 133       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 134
 135       Record.push_back(FauxAttr);
 136     }
 137
 138     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 139     Record.clear();
 140   }
 141
 142   Stream.ExitBlock();
 143 }
 144
 145 /// WriteTypeTable - Write out the type table for a module.
 146 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 147   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 148
 149   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 150   SmallVector<uint64_t, 64> TypeVals;
 151
 152   // Abbrev for TYPE_CODE_POINTER.
 153   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 154   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 156                             Log2_32_Ceil(VE.getTypes().size()+1)));
 157   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 158   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 159
 160   // Abbrev for TYPE_CODE_FUNCTION.
 161   Abbv = new BitCodeAbbrev();
 162   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 164   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 167                             Log2_32_Ceil(VE.getTypes().size()+1)));
 168   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 169
 170   // Abbrev for TYPE_CODE_STRUCT.
 171   Abbv = new BitCodeAbbrev();
 172   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 176                             Log2_32_Ceil(VE.getTypes().size()+1)));
 177   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 178
 179   // Abbrev for TYPE_CODE_ARRAY.
 180   Abbv = new BitCodeAbbrev();
 181   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 184                             Log2_32_Ceil(VE.getTypes().size()+1)));
 185   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 186
 187   // Emit an entry count so the reader can reserve space.
 188   TypeVals.push_back(TypeList.size());
 189   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 190   TypeVals.clear();
 191
 192   // Loop over all of the types, emitting each in turn.
 193   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 194     const Type *T = TypeList[i].first;
 195     int AbbrevToUse = 0;
 196     unsigned Code = 0;
 197
 198     switch (T->getTypeID()) {
 199     default: assert(0 && "Unknown type!");
 200     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 201     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 202     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 203     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 204     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 205     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 206     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 207     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 208     case Type::IntegerTyID:
 209       // INTEGER: [width]
 210       Code = bitc::TYPE_CODE_INTEGER;
 211       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 212       break;
 213     case Type::PointerTyID: {
 214       const PointerType *PTy = cast<PointerType>(T);
 215       // POINTER: [pointee type, address space]
 216       Code = bitc::TYPE_CODE_POINTER;
 217       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 218       unsigned AddressSpace = PTy->getAddressSpace();
 219       TypeVals.push_back(AddressSpace);
 220       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 221       break;
 222     }
 223     case Type::FunctionTyID: {
 224       const FunctionType *FT = cast<FunctionType>(T);
 225       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 226       Code = bitc::TYPE_CODE_FUNCTION;
 227       TypeVals.push_back(FT->isVarArg());
 228       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 229       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 230       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 231         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 232       AbbrevToUse = FunctionAbbrev;
 233       break;
 234     }
 235     case Type::StructTyID: {
 236       const StructType *ST = cast<StructType>(T);
 237       // STRUCT: [ispacked, eltty x N]
 238       Code = bitc::TYPE_CODE_STRUCT;
 239       TypeVals.push_back(ST->isPacked());
 240       // Output all of the element types.
 241       for (StructType::element_iterator I = ST->element_begin(),
 242            E = ST->element_end(); I != E; ++I)
 243         TypeVals.push_back(VE.getTypeID(*I));
 244       AbbrevToUse = StructAbbrev;
 245       break;
 246     }
 247     case Type::ArrayTyID: {
 248       const ArrayType *AT = cast<ArrayType>(T);
 249       // ARRAY: [numelts, eltty]
 250       Code = bitc::TYPE_CODE_ARRAY;
 251       TypeVals.push_back(AT->getNumElements());
 252       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 253       AbbrevToUse = ArrayAbbrev;
 254       break;
 255     }
 256     case Type::VectorTyID: {
 257       const VectorType *VT = cast<VectorType>(T);
 258       // VECTOR [numelts, eltty]
 259       Code = bitc::TYPE_CODE_VECTOR;
 260       TypeVals.push_back(VT->getNumElements());
 261       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 262       break;
 263     }
 264     }
 265
 266     // Emit the finished record.
 267     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 268     TypeVals.clear();
 269   }
 270
 271   Stream.ExitBlock();
 272 }
 273
 274 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 275   switch (GV->getLinkage()) {
 276   default: assert(0 && "Invalid linkage!");
 277   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 278   case GlobalValue::ExternalLinkage:     return 0;
 279   case GlobalValue::WeakLinkage:         return 1;
 280   case GlobalValue::AppendingLinkage:    return 2;
 281   case GlobalValue::InternalLinkage:     return 3;
 282   case GlobalValue::LinkOnceLinkage:     return 4;
 283   case GlobalValue::DLLImportLinkage:    return 5;
 284   case GlobalValue::DLLExportLinkage:    return 6;
 285   case GlobalValue::ExternalWeakLinkage: return 7;
 286   case GlobalValue::CommonLinkage:       return 8;
 287   }
 288 }
 289
 290 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 291   switch (GV->getVisibility()) {
 292   default: assert(0 && "Invalid visibility!");
 293   case GlobalValue::DefaultVisibility:   return 0;
 294   case GlobalValue::HiddenVisibility:    return 1;
 295   case GlobalValue::ProtectedVisibility: return 2;
 296   }
 297 }
 298
 299 // Emit top-level description of module, including target triple, inline asm,
 300 // descriptors for global variables, and function prototype info.
 301 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 302                             BitstreamWriter &Stream) {
 303   // Emit the list of dependent libraries for the Module.
 304   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 305     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 306
 307   // Emit various pieces of data attached to a module.
 308   if (!M->getTargetTriple().empty())
 309     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 310                       0/*TODO*/, Stream);
 311   if (!M->getDataLayout().empty())
 312     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 313                       0/*TODO*/, Stream);
 314   if (!M->getModuleInlineAsm().empty())
 315     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 316                       0/*TODO*/, Stream);
 317
 318   // Emit information about sections and GC, computing how many there are. Also
 319   // compute the maximum alignment value.
 320   std::map<std::string, unsigned> SectionMap;
 321   std::map<std::string, unsigned> GCMap;
 322   unsigned MaxAlignment = 0;
 323   unsigned MaxGlobalType = 0;
 324   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 325        GV != E; ++GV) {
 326     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 327     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 328
 329     if (!GV->hasSection()) continue;
 330     // Give section names unique ID's.
 331     unsigned &Entry = SectionMap[GV->getSection()];
 332     if (Entry != 0) continue;
 333     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 334                       0/*TODO*/, Stream);
 335     Entry = SectionMap.size();
 336   }
 337   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 338     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 339     if (F->hasSection()) {
 340       // Give section names unique ID's.
 341       unsigned &Entry = SectionMap[F->getSection()];
 342       if (!Entry) {
 343         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 344                           0/*TODO*/, Stream);
 345         Entry = SectionMap.size();
 346       }
 347     }
 348     if (F->hasGC()) {
 349       // Same for GC names.
 350       unsigned &Entry = GCMap[F->getGC()];
 351       if (!Entry) {
 352         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 353                           0/*TODO*/, Stream);
 354         Entry = GCMap.size();
 355       }
 356     }
 357   }
 358
 359   // Emit abbrev for globals, now that we know # sections and max alignment.
 360   unsigned SimpleGVarAbbrev = 0;
 361   if (!M->global_empty()) {
 362     // Add an abbrev for common globals with no visibility or thread localness.
 363     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 364     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 366                               Log2_32_Ceil(MaxGlobalType+1)));
 367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 368     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 370     if (MaxAlignment == 0)                                      // Alignment.
 371       Abbv->Add(BitCodeAbbrevOp(0));
 372     else {
 373       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 374       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 375                                Log2_32_Ceil(MaxEncAlignment+1)));
 376     }
 377     if (SectionMap.empty())                                    // Section.
 378       Abbv->Add(BitCodeAbbrevOp(0));
 379     else
 380       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 381                                Log2_32_Ceil(SectionMap.size()+1)));
 382     // Don't bother emitting vis + thread local.
 383     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 384   }
 385
 386   // Emit the global variable information.
 387   SmallVector<unsigned, 64> Vals;
 388   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 389        GV != E; ++GV) {
 390     unsigned AbbrevToUse = 0;
 391
 392     // GLOBALVAR: [type, isconst, initid,
 393     //             linkage, alignment, section, visibility, threadlocal]
 394     Vals.push_back(VE.getTypeID(GV->getType()));
 395     Vals.push_back(GV->isConstant());
 396     Vals.push_back(GV->isDeclaration() ? 0 :
 397                    (VE.getValueID(GV->getInitializer()) + 1));
 398     Vals.push_back(getEncodedLinkage(GV));
 399     Vals.push_back(Log2_32(GV->getAlignment())+1);
 400     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 401     if (GV->isThreadLocal() ||
 402         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 403       Vals.push_back(getEncodedVisibility(GV));
 404       Vals.push_back(GV->isThreadLocal());
 405     } else {
 406       AbbrevToUse = SimpleGVarAbbrev;
 407     }
 408
 409     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 410     Vals.clear();
 411   }
 412
 413   // Emit the function proto information.
 414   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 415     // FUNCTION:  [type, callingconv, isproto, paramattr,
 416     //             linkage, alignment, section, visibility, gc]
 417     Vals.push_back(VE.getTypeID(F->getType()));
 418     Vals.push_back(F->getCallingConv());
 419     Vals.push_back(F->isDeclaration());
 420     Vals.push_back(getEncodedLinkage(F));
 421     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 422     Vals.push_back(Log2_32(F->getAlignment())+1);
 423     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 424     Vals.push_back(getEncodedVisibility(F));
 425     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 426
 427     unsigned AbbrevToUse = 0;
 428     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 429     Vals.clear();
 430   }
 431
 432
 433   // Emit the alias information.
 434   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 435        AI != E; ++AI) {
 436     Vals.push_back(VE.getTypeID(AI->getType()));
 437     Vals.push_back(VE.getValueID(AI->getAliasee()));
 438     Vals.push_back(getEncodedLinkage(AI));
 439     Vals.push_back(getEncodedVisibility(AI));
 440     unsigned AbbrevToUse = 0;
 441     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 442     Vals.clear();
 443   }
 444 }
 445
 446
 447 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 448                            const ValueEnumerator &VE,
 449                            BitstreamWriter &Stream, bool isGlobal) {
 450   if (FirstVal == LastVal) return;
 451
 452   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 453
 454   unsigned AggregateAbbrev = 0;
 455   unsigned String8Abbrev = 0;
 456   unsigned CString7Abbrev = 0;
 457   unsigned CString6Abbrev = 0;
 458   // If this is a constant pool for the module, emit module-specific abbrevs.
 459   if (isGlobal) {
 460     // Abbrev for CST_CODE_AGGREGATE.
 461     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 462     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 465     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 466
 467     // Abbrev for CST_CODE_STRING.
 468     Abbv = new BitCodeAbbrev();
 469     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 472     String8Abbrev = Stream.EmitAbbrev(Abbv);
 473     // Abbrev for CST_CODE_CSTRING.
 474     Abbv = new BitCodeAbbrev();
 475     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 478     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 479     // Abbrev for CST_CODE_CSTRING.
 480     Abbv = new BitCodeAbbrev();
 481     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 484     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 485   }
 486
 487   SmallVector<uint64_t, 64> Record;
 488
 489   const ValueEnumerator::ValueList &Vals = VE.getValues();
 490   const Type *LastTy = 0;
 491   for (unsigned i = FirstVal; i != LastVal; ++i) {
 492     const Value *V = Vals[i].first;
 493     // If we need to switch types, do so now.
 494     if (V->getType() != LastTy) {
 495       LastTy = V->getType();
 496       Record.push_back(VE.getTypeID(LastTy));
 497       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 498                         CONSTANTS_SETTYPE_ABBREV);
 499       Record.clear();
 500     }
 501
 502     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 503       Record.push_back(unsigned(IA->hasSideEffects()));
 504
 505       // Add the asm string.
 506       const std::string &AsmStr = IA->getAsmString();
 507       Record.push_back(AsmStr.size());
 508       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 509         Record.push_back(AsmStr[i]);
 510
 511       // Add the constraint string.
 512       const std::string &ConstraintStr = IA->getConstraintString();
 513       Record.push_back(ConstraintStr.size());
 514       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 515         Record.push_back(ConstraintStr[i]);
 516       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 517       Record.clear();
 518       continue;
 519     }
 520     const Constant *C = cast<Constant>(V);
 521     unsigned Code = -1U;
 522     unsigned AbbrevToUse = 0;
 523     if (C->isNullValue()) {
 524       Code = bitc::CST_CODE_NULL;
 525     } else if (isa<UndefValue>(C)) {
 526       Code = bitc::CST_CODE_UNDEF;
 527     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 528       if (IV->getBitWidth() <= 64) {
 529         int64_t V = IV->getSExtValue();
 530         if (V >= 0)
 531           Record.push_back(V << 1);
 532         else
 533           Record.push_back((-V << 1) | 1);
 534         Code = bitc::CST_CODE_INTEGER;
 535         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 536       } else {                             // Wide integers, > 64 bits in size.
 537         // We have an arbitrary precision integer value to write whose
 538         // bit width is > 64. However, in canonical unsigned integer
 539         // format it is likely that the high bits are going to be zero.
 540         // So, we only write the number of active words.
 541         unsigned NWords = IV->getValue().getActiveWords();
 542         const uint64_t *RawWords = IV->getValue().getRawData();
 543         for (unsigned i = 0; i != NWords; ++i) {
 544           int64_t V = RawWords[i];
 545           if (V >= 0)
 546             Record.push_back(V << 1);
 547           else
 548             Record.push_back((-V << 1) | 1);
 549         }
 550         Code = bitc::CST_CODE_WIDE_INTEGER;
 551       }
 552     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 553       Code = bitc::CST_CODE_FLOAT;
 554       const Type *Ty = CFP->getType();
 555       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 556         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 557       } else if (Ty == Type::X86_FP80Ty) {
 558         // api needed to prevent premature destruction
 559         APInt api = CFP->getValueAPF().bitcastToAPInt();
 560         const uint64_t *p = api.getRawData();
 561         Record.push_back(p[0]);
 562         Record.push_back((uint16_t)p[1]);
 563       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 564         APInt api = CFP->getValueAPF().bitcastToAPInt();
 565         const uint64_t *p = api.getRawData();
 566         Record.push_back(p[0]);
 567         Record.push_back(p[1]);
 568       } else {
 569         assert (0 && "Unknown FP type!");
 570       }
 571     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 572       // Emit constant strings specially.
 573       unsigned NumOps = C->getNumOperands();
 574       // If this is a null-terminated string, use the denser CSTRING encoding.
 575       if (C->getOperand(NumOps-1)->isNullValue()) {
 576         Code = bitc::CST_CODE_CSTRING;
 577         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 578       } else {
 579         Code = bitc::CST_CODE_STRING;
 580         AbbrevToUse = String8Abbrev;
 581       }
 582       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 583       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 584       for (unsigned i = 0; i != NumOps; ++i) {
 585         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 586         Record.push_back(V);
 587         isCStr7 &= (V & 128) == 0;
 588         if (isCStrChar6)
 589           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 590       }
 591
 592       if (isCStrChar6)
 593         AbbrevToUse = CString6Abbrev;
 594       else if (isCStr7)
 595         AbbrevToUse = CString7Abbrev;
 596     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 597                isa<ConstantVector>(V)) {
 598       Code = bitc::CST_CODE_AGGREGATE;
 599       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 600         Record.push_back(VE.getValueID(C->getOperand(i)));
 601       AbbrevToUse = AggregateAbbrev;
 602     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 603       switch (CE->getOpcode()) {
 604       default:
 605         if (Instruction::isCast(CE->getOpcode())) {
 606           Code = bitc::CST_CODE_CE_CAST;
 607           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 608           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 609           Record.push_back(VE.getValueID(C->getOperand(0)));
 610           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 611         } else {
 612           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 613           Code = bitc::CST_CODE_CE_BINOP;
 614           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 615           Record.push_back(VE.getValueID(C->getOperand(0)));
 616           Record.push_back(VE.getValueID(C->getOperand(1)));
 617         }
 618         break;
 619       case Instruction::GetElementPtr:
 620         Code = bitc::CST_CODE_CE_GEP;
 621         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 622           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 623           Record.push_back(VE.getValueID(C->getOperand(i)));
 624         }
 625         break;
 626       case Instruction::Select:
 627         Code = bitc::CST_CODE_CE_SELECT;
 628         Record.push_back(VE.getValueID(C->getOperand(0)));
 629         Record.push_back(VE.getValueID(C->getOperand(1)));
 630         Record.push_back(VE.getValueID(C->getOperand(2)));
 631         break;
 632       case Instruction::ExtractElement:
 633         Code = bitc::CST_CODE_CE_EXTRACTELT;
 634         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 635         Record.push_back(VE.getValueID(C->getOperand(0)));
 636         Record.push_back(VE.getValueID(C->getOperand(1)));
 637         break;
 638       case Instruction::InsertElement:
 639         Code = bitc::CST_CODE_CE_INSERTELT;
 640         Record.push_back(VE.getValueID(C->getOperand(0)));
 641         Record.push_back(VE.getValueID(C->getOperand(1)));
 642         Record.push_back(VE.getValueID(C->getOperand(2)));
 643         break;
 644       case Instruction::ShuffleVector:
 645         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 646         Record.push_back(VE.getValueID(C->getOperand(0)));
 647         Record.push_back(VE.getValueID(C->getOperand(1)));
 648         Record.push_back(VE.getValueID(C->getOperand(2)));
 649         break;
 650       case Instruction::ICmp:
 651       case Instruction::FCmp:
 652       case Instruction::VICmp:
 653       case Instruction::VFCmp:
 654         if (isa<VectorType>(C->getOperand(0)->getType())
 655             && (CE->getOpcode() == Instruction::ICmp
 656                 || CE->getOpcode() == Instruction::FCmp)) {
 657           // compare returning vector of Int1Ty
 658           assert(0 && "Unsupported constant!");
 659         } else {
 660           Code = bitc::CST_CODE_CE_CMP;
 661         }
 662         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 663         Record.push_back(VE.getValueID(C->getOperand(0)));
 664         Record.push_back(VE.getValueID(C->getOperand(1)));
 665         Record.push_back(CE->getPredicate());
 666         break;
 667       }
 668     } else {
 669       assert(0 && "Unknown constant!");
 670     }
 671     Stream.EmitRecord(Code, Record, AbbrevToUse);
 672     Record.clear();
 673   }
 674
 675   Stream.ExitBlock();
 676 }
 677
 678 static void WriteModuleConstants(const ValueEnumerator &VE,
 679                                  BitstreamWriter &Stream) {
 680   const ValueEnumerator::ValueList &Vals = VE.getValues();
 681
 682   // Find the first constant to emit, which is the first non-globalvalue value.
 683   // We know globalvalues have been emitted by WriteModuleInfo.
 684   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 685     if (!isa<GlobalValue>(Vals[i].first)) {
 686       WriteConstants(i, Vals.size(), VE, Stream, true);
 687       return;
 688     }
 689   }
 690 }
 691
 692 /// PushValueAndType - The file has to encode both the value and type id for
 693 /// many values, because we need to know what type to create for forward
 694 /// references.  However, most operands are not forward references, so this type
 695 /// field is not needed.
 696 ///
 697 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 698 /// instruction ID, then it is a forward reference, and it also includes the
 699 /// type ID.
 700 static bool PushValueAndType(Value *V, unsigned InstID,
 701                              SmallVector<unsigned, 64> &Vals,
 702                              ValueEnumerator &VE) {
 703   unsigned ValID = VE.getValueID(V);
 704   Vals.push_back(ValID);
 705   if (ValID >= InstID) {
 706     Vals.push_back(VE.getTypeID(V->getType()));
 707     return true;
 708   }
 709   return false;
 710 }
 711
 712 /// WriteInstruction - Emit an instruction to the specified stream.
 713 static void WriteInstruction(const Instruction &I, unsigned InstID,
 714                              ValueEnumerator &VE, BitstreamWriter &Stream,
 715                              SmallVector<unsigned, 64> &Vals) {
 716   unsigned Code = 0;
 717   unsigned AbbrevToUse = 0;
 718   switch (I.getOpcode()) {
 719   default:
 720     if (Instruction::isCast(I.getOpcode())) {
 721       Code = bitc::FUNC_CODE_INST_CAST;
 722       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 723         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 724       Vals.push_back(VE.getTypeID(I.getType()));
 725       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 726     } else {
 727       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 728       Code = bitc::FUNC_CODE_INST_BINOP;
 729       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 730         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 731       Vals.push_back(VE.getValueID(I.getOperand(1)));
 732       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 733     }
 734     break;
 735
 736   case Instruction::GetElementPtr:
 737     Code = bitc::FUNC_CODE_INST_GEP;
 738     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 739       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 740     break;
 741   case Instruction::ExtractValue: {
 742     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 743     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 744     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 745     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 746       Vals.push_back(*i);
 747     break;
 748   }
 749   case Instruction::InsertValue: {
 750     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 751     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 752     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 753     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 754     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 755       Vals.push_back(*i);
 756     break;
 757   }
 758   case Instruction::Select:
 759     Code = bitc::FUNC_CODE_INST_VSELECT;
 760     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 761     Vals.push_back(VE.getValueID(I.getOperand(2)));
 762     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 763     break;
 764   case Instruction::ExtractElement:
 765     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 766     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 767     Vals.push_back(VE.getValueID(I.getOperand(1)));
 768     break;
 769   case Instruction::InsertElement:
 770     Code = bitc::FUNC_CODE_INST_INSERTELT;
 771     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 772     Vals.push_back(VE.getValueID(I.getOperand(1)));
 773     Vals.push_back(VE.getValueID(I.getOperand(2)));
 774     break;
 775   case Instruction::ShuffleVector:
 776     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 777     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 778     Vals.push_back(VE.getValueID(I.getOperand(1)));
 779     Vals.push_back(VE.getValueID(I.getOperand(2)));
 780     break;
 781   case Instruction::ICmp:
 782   case Instruction::FCmp:
 783   case Instruction::VICmp:
 784   case Instruction::VFCmp:
 785     if (I.getOpcode() == Instruction::ICmp
 786         || I.getOpcode() == Instruction::FCmp) {
 787       // compare returning Int1Ty or vector of Int1Ty
 788       Code = bitc::FUNC_CODE_INST_CMP2;
 789     } else {
 790       Code = bitc::FUNC_CODE_INST_CMP;
 791     }
 792     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 793     Vals.push_back(VE.getValueID(I.getOperand(1)));
 794     Vals.push_back(cast<CmpInst>(I).getPredicate());
 795     break;
 796
 797   case Instruction::Ret:
 798     {
 799       Code = bitc::FUNC_CODE_INST_RET;
 800       unsigned NumOperands = I.getNumOperands();
 801       if (NumOperands == 0)
 802         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 803       else if (NumOperands == 1) {
 804         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 805           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 806       } else {
 807         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 808           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 809       }
 810     }
 811     break;
 812   case Instruction::Br:
 813     Code = bitc::FUNC_CODE_INST_BR;
 814     Vals.push_back(VE.getValueID(I.getOperand(0)));
 815     if (cast<BranchInst>(I).isConditional()) {
 816       Vals.push_back(VE.getValueID(I.getOperand(1)));
 817       Vals.push_back(VE.getValueID(I.getOperand(2)));
 818     }
 819     break;
 820   case Instruction::Switch:
 821     Code = bitc::FUNC_CODE_INST_SWITCH;
 822     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 823     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 824       Vals.push_back(VE.getValueID(I.getOperand(i)));
 825     break;
 826   case Instruction::Invoke: {
 827     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 828     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 829     Code = bitc::FUNC_CODE_INST_INVOKE;
 830
 831     const InvokeInst *II = cast<InvokeInst>(&I);
 832     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 833     Vals.push_back(II->getCallingConv());
 834     Vals.push_back(VE.getValueID(II->getNormalDest()));
 835     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 836     PushValueAndType(II->getCalledFunction(), InstID, Vals, VE);
 837
 838     // Emit value #'s for the fixed parameters.
 839     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 840       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 841
 842     // Emit type/value pairs for varargs params.
 843     if (FTy->isVarArg()) {
 844       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 845            i != e; ++i)
 846         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 847     }
 848     break;
 849   }
 850   case Instruction::Unwind:
 851     Code = bitc::FUNC_CODE_INST_UNWIND;
 852     break;
 853   case Instruction::Unreachable:
 854     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 855     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 856     break;
 857
 858   case Instruction::PHI:
 859     Code = bitc::FUNC_CODE_INST_PHI;
 860     Vals.push_back(VE.getTypeID(I.getType()));
 861     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 862       Vals.push_back(VE.getValueID(I.getOperand(i)));
 863     break;
 864
 865   case Instruction::Malloc:
 866     Code = bitc::FUNC_CODE_INST_MALLOC;
 867     Vals.push_back(VE.getTypeID(I.getType()));
 868     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 869     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 870     break;
 871
 872   case Instruction::Free:
 873     Code = bitc::FUNC_CODE_INST_FREE;
 874     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 875     break;
 876
 877   case Instruction::Alloca:
 878     Code = bitc::FUNC_CODE_INST_ALLOCA;
 879     Vals.push_back(VE.getTypeID(I.getType()));
 880     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 881     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 882     break;
 883
 884   case Instruction::Load:
 885     Code = bitc::FUNC_CODE_INST_LOAD;
 886     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 887       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 888
 889     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 890     Vals.push_back(cast<LoadInst>(I).isVolatile());
 891     break;
 892   case Instruction::Store:
 893     Code = bitc::FUNC_CODE_INST_STORE2;
 894     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 895     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 896     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 897     Vals.push_back(cast<StoreInst>(I).isVolatile());
 898     break;
 899   case Instruction::Call: {
 900     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 901     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 902
 903     Code = bitc::FUNC_CODE_INST_CALL;
 904
 905     const CallInst *CI = cast<CallInst>(&I);
 906     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 907     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 908     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 909
 910     // Emit value #'s for the fixed parameters.
 911     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 912       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 913
 914     // Emit type/value pairs for varargs params.
 915     if (FTy->isVarArg()) {
 916       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 917       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 918            i != e; ++i)
 919         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 920     }
 921     break;
 922   }
 923   case Instruction::VAArg:
 924     Code = bitc::FUNC_CODE_INST_VAARG;
 925     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 926     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 927     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 928     break;
 929   }
 930
 931   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 932   Vals.clear();
 933 }
 934
 935 // Emit names for globals/functions etc.
 936 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 937                                   const ValueEnumerator &VE,
 938                                   BitstreamWriter &Stream) {
 939   if (VST.empty()) return;
 940   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 941
 942   // FIXME: Set up the abbrev, we know how many values there are!
 943   // FIXME: We know if the type names can use 7-bit ascii.
 944   SmallVector<unsigned, 64> NameVals;
 945
 946   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 947        SI != SE; ++SI) {
 948
 949     const ValueName &Name = *SI;
 950
 951     // Figure out the encoding to use for the name.
 952     bool is7Bit = true;
 953     bool isChar6 = true;
 954     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 955          C != E; ++C) {
 956       if (isChar6)
 957         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 958       if ((unsigned char)*C & 128) {
 959         is7Bit = false;
 960         break;  // don't bother scanning the rest.
 961       }
 962     }
 963
 964     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 965
 966     // VST_ENTRY:   [valueid, namechar x N]
 967     // VST_BBENTRY: [bbid, namechar x N]
 968     unsigned Code;
 969     if (isa<BasicBlock>(SI->getValue())) {
 970       Code = bitc::VST_CODE_BBENTRY;
 971       if (isChar6)
 972         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 973     } else {
 974       Code = bitc::VST_CODE_ENTRY;
 975       if (isChar6)
 976         AbbrevToUse = VST_ENTRY_6_ABBREV;
 977       else if (is7Bit)
 978         AbbrevToUse = VST_ENTRY_7_ABBREV;
 979     }
 980
 981     NameVals.push_back(VE.getValueID(SI->getValue()));
 982     for (const char *P = Name.getKeyData(),
 983          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 984       NameVals.push_back((unsigned char)*P);
 985
 986     // Emit the finished record.
 987     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 988     NameVals.clear();
 989   }
 990   Stream.ExitBlock();
 991 }
 992
 993 /// WriteFunction - Emit a function body to the module stream.
 994 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 995                           BitstreamWriter &Stream) {
 996   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
 997   VE.incorporateFunction(F);
 998
 999   SmallVector<unsigned, 64> Vals;
1000
1001   // Emit the number of basic blocks, so the reader can create them ahead of
1002   // time.
1003   Vals.push_back(VE.getBasicBlocks().size());
1004   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1005   Vals.clear();
1006
1007   // If there are function-local constants, emit them now.
1008   unsigned CstStart, CstEnd;
1009   VE.getFunctionConstantRange(CstStart, CstEnd);
1010   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1011
1012   // Keep a running idea of what the instruction ID is.
1013   unsigned InstID = CstEnd;
1014
1015   // Finally, emit all the instructions, in order.
1016   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1017     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1018          I != E; ++I) {
1019       WriteInstruction(*I, InstID, VE, Stream, Vals);
1020       if (I->getType() != Type::VoidTy)
1021         ++InstID;
1022     }
1023
1024   // Emit names for all the instructions etc.
1025   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1026
1027   VE.purgeFunction();
1028   Stream.ExitBlock();
1029 }
1030
1031 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1032 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1033                                  const ValueEnumerator &VE,
1034                                  BitstreamWriter &Stream) {
1035   if (TST.empty()) return;
1036
1037   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1038
1039   // 7-bit fixed width VST_CODE_ENTRY strings.
1040   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1041   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1043                             Log2_32_Ceil(VE.getTypes().size()+1)));
1044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1046   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1047
1048   SmallVector<unsigned, 64> NameVals;
1049
1050   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1051        TI != TE; ++TI) {
1052     // TST_ENTRY: [typeid, namechar x N]
1053     NameVals.push_back(VE.getTypeID(TI->second));
1054
1055     const std::string &Str = TI->first;
1056     bool is7Bit = true;
1057     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1058       NameVals.push_back((unsigned char)Str[i]);
1059       if (Str[i] & 128)
1060         is7Bit = false;
1061     }
1062
1063     // Emit the finished record.
1064     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1065     NameVals.clear();
1066   }
1067
1068   Stream.ExitBlock();
1069 }
1070
1071 // Emit blockinfo, which defines the standard abbreviations etc.
1072 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1073   // We only want to emit block info records for blocks that have multiple
1074   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1075   // blocks can defined their abbrevs inline.
1076   Stream.EnterBlockInfoBlock(2);
1077
1078   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1079     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1080     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1081     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1082     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1083     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1084     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1085                                    Abbv) != VST_ENTRY_8_ABBREV)
1086       assert(0 && "Unexpected abbrev ordering!");
1087   }
1088
1089   { // 7-bit fixed width VST_ENTRY strings.
1090     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1091     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1092     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1093     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1094     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1095     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1096                                    Abbv) != VST_ENTRY_7_ABBREV)
1097       assert(0 && "Unexpected abbrev ordering!");
1098   }
1099   { // 6-bit char6 VST_ENTRY strings.
1100     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1101     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1104     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1105     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1106                                    Abbv) != VST_ENTRY_6_ABBREV)
1107       assert(0 && "Unexpected abbrev ordering!");
1108   }
1109   { // 6-bit char6 VST_BBENTRY strings.
1110     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1111     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1112     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1113     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1114     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1115     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1116                                    Abbv) != VST_BBENTRY_6_ABBREV)
1117       assert(0 && "Unexpected abbrev ordering!");
1118   }
1119
1120
1121
1122   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1123     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1124     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1126                               Log2_32_Ceil(VE.getTypes().size()+1)));
1127     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1128                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1129       assert(0 && "Unexpected abbrev ordering!");
1130   }
1131
1132   { // INTEGER abbrev for CONSTANTS_BLOCK.
1133     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1134     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1136     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1137                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1138       assert(0 && "Unexpected abbrev ordering!");
1139   }
1140
1141   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1142     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1143     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1144     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1145     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1146                               Log2_32_Ceil(VE.getTypes().size()+1)));
1147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1148
1149     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1150                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1151       assert(0 && "Unexpected abbrev ordering!");
1152   }
1153   { // NULL abbrev for CONSTANTS_BLOCK.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1156     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1157                                    Abbv) != CONSTANTS_NULL_Abbrev)
1158       assert(0 && "Unexpected abbrev ordering!");
1159   }
1160
1161   // FIXME: This should only use space for first class types!
1162
1163   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1164     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1165     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1169     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1170                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1171       assert(0 && "Unexpected abbrev ordering!");
1172   }
1173   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1174     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1175     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1179     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1180                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1181       assert(0 && "Unexpected abbrev ordering!");
1182   }
1183   { // INST_CAST abbrev for FUNCTION_BLOCK.
1184     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1185     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1188                               Log2_32_Ceil(VE.getTypes().size()+1)));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1190     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1191                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1192       assert(0 && "Unexpected abbrev ordering!");
1193   }
1194
1195   { // INST_RET abbrev for FUNCTION_BLOCK.
1196     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1197     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1198     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1199                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1200       assert(0 && "Unexpected abbrev ordering!");
1201   }
1202   { // INST_RET abbrev for FUNCTION_BLOCK.
1203     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1204     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1206     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1207                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1208       assert(0 && "Unexpected abbrev ordering!");
1209   }
1210   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1211     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1212     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1213     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1214                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1215       assert(0 && "Unexpected abbrev ordering!");
1216   }
1217
1218   Stream.ExitBlock();
1219 }
1220
1221
1222 /// WriteModule - Emit the specified module to the bitstream.
1223 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1224   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1225
1226   // Emit the version number if it is non-zero.
1227   if (CurVersion) {
1228     SmallVector<unsigned, 1> Vals;
1229     Vals.push_back(CurVersion);
1230     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1231   }
1232
1233   // Analyze the module, enumerating globals, functions, etc.
1234   ValueEnumerator VE(M);
1235
1236   // Emit blockinfo, which defines the standard abbreviations etc.
1237   WriteBlockInfo(VE, Stream);
1238
1239   // Emit information about parameter attributes.
1240   WriteAttributeTable(VE, Stream);
1241
1242   // Emit information describing all of the types in the module.
1243   WriteTypeTable(VE, Stream);
1244
1245   // Emit top-level description of module, including target triple, inline asm,
1246   // descriptors for global variables, and function prototype info.
1247   WriteModuleInfo(M, VE, Stream);
1248
1249   // Emit constants.
1250   WriteModuleConstants(VE, Stream);
1251
1252   // If we have any aggregate values in the value table, purge them - these can
1253   // only be used to initialize global variables.  Doing so makes the value
1254   // namespace smaller for code in functions.
1255   int NumNonAggregates = VE.PurgeAggregateValues();
1256   if (NumNonAggregates != -1) {
1257     SmallVector<unsigned, 1> Vals;
1258     Vals.push_back(NumNonAggregates);
1259     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1260   }
1261
1262   // Emit function bodies.
1263   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1264     if (!I->isDeclaration())
1265       WriteFunction(*I, VE, Stream);
1266
1267   // Emit the type symbol table information.
1268   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1269
1270   // Emit names for globals/functions etc.
1271   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1272
1273   Stream.ExitBlock();
1274 }
1275
1276 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1277 /// header and trailer to make it compatible with the system archiver.  To do
1278 /// this we emit the following header, and then emit a trailer that pads the
1279 /// file out to be a multiple of 16 bytes.
1280 ///
1281 /// struct bc_header {
1282 ///   uint32_t Magic;         // 0x0B17C0DE
1283 ///   uint32_t Version;       // Version, currently always 0.
1284 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1285 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1286 ///   uint32_t CPUType;       // CPU specifier.
1287 ///   ... potentially more later ...
1288 /// };
1289 enum {
1290   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1291   DarwinBCHeaderSize = 5*4
1292 };
1293
1294 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1295                                const std::string &TT) {
1296   unsigned CPUType = ~0U;
1297
1298   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1299   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1300   // specific constants here because they are implicitly part of the Darwin ABI.
1301   enum {
1302     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1303     DARWIN_CPU_TYPE_X86        = 7,
1304     DARWIN_CPU_TYPE_POWERPC    = 18
1305   };
1306
1307   if (TT.find("x86_64-") == 0)
1308     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1309   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1310            TT[4] == '-' && TT[1] - '3' < 6)
1311     CPUType = DARWIN_CPU_TYPE_X86;
1312   else if (TT.find("powerpc-") == 0)
1313     CPUType = DARWIN_CPU_TYPE_POWERPC;
1314   else if (TT.find("powerpc64-") == 0)
1315     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1316
1317   // Traditional Bitcode starts after header.
1318   unsigned BCOffset = DarwinBCHeaderSize;
1319
1320   Stream.Emit(0x0B17C0DE, 32);
1321   Stream.Emit(0         , 32);  // Version.
1322   Stream.Emit(BCOffset  , 32);
1323   Stream.Emit(0         , 32);  // Filled in later.
1324   Stream.Emit(CPUType   , 32);
1325 }
1326
1327 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1328 /// finalize the header.
1329 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1330   // Update the size field in the header.
1331   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1332
1333   // If the file is not a multiple of 16 bytes, insert dummy padding.
1334   while (BufferSize & 15) {
1335     Stream.Emit(0, 8);
1336     ++BufferSize;
1337   }
1338 }
1339
1340
1341 /// WriteBitcodeToFile - Write the specified module to the specified output
1342 /// stream.
1343 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1344   raw_os_ostream RawOut(Out);
1345   // If writing to stdout, set binary mode.
1346   if (llvm::cout == Out)
1347     sys::Program::ChangeStdoutToBinary();
1348   WriteBitcodeToFile(M, RawOut);
1349 }
1350
1351 /// WriteBitcodeToFile - Write the specified module to the specified output
1352 /// stream.
1353 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1354   std::vector<unsigned char> Buffer;
1355   BitstreamWriter Stream(Buffer);
1356
1357   Buffer.reserve(256*1024);
1358
1359   WriteBitcodeToStream( M, Stream );
1360
1361   // If writing to stdout, set binary mode.
1362   if (&llvm::outs() == &Out)
1363     sys::Program::ChangeStdoutToBinary();
1364
1365   // Write the generated bitstream to "Out".
1366   Out.write((char*)&Buffer.front(), Buffer.size());
1367
1368   // Make sure it hits disk now.
1369   Out.flush();
1370 }
1371
1372 /// WriteBitcodeToStream - Write the specified module to the specified output
1373 /// stream.
1374 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1375   // If this is darwin, emit a file header and trailer if needed.
1376   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1377   if (isDarwin)
1378     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1379
1380   // Emit the file header.
1381   Stream.Emit((unsigned)'B', 8);
1382   Stream.Emit((unsigned)'C', 8);
1383   Stream.Emit(0x0, 4);
1384   Stream.Emit(0xC, 4);
1385   Stream.Emit(0xE, 4);
1386   Stream.Emit(0xD, 4);
1387
1388   // Emit the module.
1389   WriteModule(M, Stream);
1390
1391   if (isDarwin)
1392     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1393 }