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/MDNode.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/TypeSymbolTable.h"
  25 #include "llvm/ValueSymbolTable.h"
  26 #include "llvm/Support/MathExtras.h"
  27 #include "llvm/Support/Streams.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include "llvm/System/Program.h"
  30 using namespace llvm;
  31
  32 /// These are manifest constants used by the bitcode writer. They do not need to
  33 /// be kept in sync with the reader, but need to be consistent within this file.
  34 enum {
  35   CurVersion = 0,
  36
  37   // VALUE_SYMTAB_BLOCK abbrev id's.
  38   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  39   VST_ENTRY_7_ABBREV,
  40   VST_ENTRY_6_ABBREV,
  41   VST_BBENTRY_6_ABBREV,
  42
  43   // CONSTANTS_BLOCK abbrev id's.
  44   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  45   CONSTANTS_INTEGER_ABBREV,
  46   CONSTANTS_CE_CAST_Abbrev,
  47   CONSTANTS_NULL_Abbrev,
  48
  49   // FUNCTION_BLOCK abbrev id's.
  50   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  51   FUNCTION_INST_BINOP_ABBREV,
  52   FUNCTION_INST_CAST_ABBREV,
  53   FUNCTION_INST_RET_VOID_ABBREV,
  54   FUNCTION_INST_RET_VAL_ABBREV,
  55   FUNCTION_INST_UNREACHABLE_ABBREV
  56 };
  57
  58
  59 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  60   switch (Opcode) {
  61   default: assert(0 && "Unknown cast instruction!");
  62   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  63   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  64   case Instruction::SExt    : return bitc::CAST_SEXT;
  65   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  66   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  67   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  68   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  69   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  70   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  71   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  72   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  73   case Instruction::BitCast : return bitc::CAST_BITCAST;
  74   }
  75 }
  76
  77 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  78   switch (Opcode) {
  79   default: assert(0 && "Unknown binary instruction!");
  80   case Instruction::Add:  return bitc::BINOP_ADD;
  81   case Instruction::Sub:  return bitc::BINOP_SUB;
  82   case Instruction::Mul:  return bitc::BINOP_MUL;
  83   case Instruction::UDiv: return bitc::BINOP_UDIV;
  84   case Instruction::FDiv:
  85   case Instruction::SDiv: return bitc::BINOP_SDIV;
  86   case Instruction::URem: return bitc::BINOP_UREM;
  87   case Instruction::FRem:
  88   case Instruction::SRem: return bitc::BINOP_SREM;
  89   case Instruction::Shl:  return bitc::BINOP_SHL;
  90   case Instruction::LShr: return bitc::BINOP_LSHR;
  91   case Instruction::AShr: return bitc::BINOP_ASHR;
  92   case Instruction::And:  return bitc::BINOP_AND;
  93   case Instruction::Or:   return bitc::BINOP_OR;
  94   case Instruction::Xor:  return bitc::BINOP_XOR;
  95   }
  96 }
  97
  98
  99
 100 static void WriteStringRecord(unsigned Code, const std::string &Str,
 101                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 102   SmallVector<unsigned, 64> Vals;
 103
 104   // Code: [strchar x N]
 105   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 106     Vals.push_back(Str[i]);
 107
 108   // Emit the finished record.
 109   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 110 }
 111
 112 // Emit information about parameter attributes.
 113 static void WriteAttributeTable(const ValueEnumerator &VE,
 114                                 BitstreamWriter &Stream) {
 115   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 116   if (Attrs.empty()) return;
 117
 118   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 119
 120   SmallVector<uint64_t, 64> Record;
 121   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 122     const AttrListPtr &A = Attrs[i];
 123     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 124       const AttributeWithIndex &PAWI = A.getSlot(i);
 125       Record.push_back(PAWI.Index);
 126
 127       // FIXME: remove in LLVM 3.0
 128       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 129       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 130       // 11 bits.
 131       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 132       if (PAWI.Attrs & Attribute::Alignment)
 133         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 134       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 135
 136       Record.push_back(FauxAttr);
 137     }
 138
 139     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 140     Record.clear();
 141   }
 142
 143   Stream.ExitBlock();
 144 }
 145
 146 /// WriteTypeTable - Write out the type table for a module.
 147 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 148   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 149
 150   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 151   SmallVector<uint64_t, 64> TypeVals;
 152
 153   // Abbrev for TYPE_CODE_POINTER.
 154   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 155   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 157                             Log2_32_Ceil(VE.getTypes().size()+1)));
 158   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 159   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 160
 161   // Abbrev for TYPE_CODE_FUNCTION.
 162   Abbv = new BitCodeAbbrev();
 163   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 165   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 168                             Log2_32_Ceil(VE.getTypes().size()+1)));
 169   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 170
 171   // Abbrev for TYPE_CODE_STRUCT.
 172   Abbv = new BitCodeAbbrev();
 173   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 177                             Log2_32_Ceil(VE.getTypes().size()+1)));
 178   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 179
 180   // Abbrev for TYPE_CODE_ARRAY.
 181   Abbv = new BitCodeAbbrev();
 182   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 185                             Log2_32_Ceil(VE.getTypes().size()+1)));
 186   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 187
 188   // Emit an entry count so the reader can reserve space.
 189   TypeVals.push_back(TypeList.size());
 190   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 191   TypeVals.clear();
 192
 193   // Loop over all of the types, emitting each in turn.
 194   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 195     const Type *T = TypeList[i].first;
 196     int AbbrevToUse = 0;
 197     unsigned Code = 0;
 198
 199     switch (T->getTypeID()) {
 200     default: assert(0 && "Unknown type!");
 201     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 202     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 203     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 204     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 205     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 206     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 207     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 208     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 209     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 210     case Type::IntegerTyID:
 211       // INTEGER: [width]
 212       Code = bitc::TYPE_CODE_INTEGER;
 213       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 214       break;
 215     case Type::PointerTyID: {
 216       const PointerType *PTy = cast<PointerType>(T);
 217       // POINTER: [pointee type, address space]
 218       Code = bitc::TYPE_CODE_POINTER;
 219       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 220       unsigned AddressSpace = PTy->getAddressSpace();
 221       TypeVals.push_back(AddressSpace);
 222       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 223       break;
 224     }
 225     case Type::FunctionTyID: {
 226       const FunctionType *FT = cast<FunctionType>(T);
 227       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 228       Code = bitc::TYPE_CODE_FUNCTION;
 229       TypeVals.push_back(FT->isVarArg());
 230       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 231       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 232       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 233         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 234       AbbrevToUse = FunctionAbbrev;
 235       break;
 236     }
 237     case Type::StructTyID: {
 238       const StructType *ST = cast<StructType>(T);
 239       // STRUCT: [ispacked, eltty x N]
 240       Code = bitc::TYPE_CODE_STRUCT;
 241       TypeVals.push_back(ST->isPacked());
 242       // Output all of the element types.
 243       for (StructType::element_iterator I = ST->element_begin(),
 244            E = ST->element_end(); I != E; ++I)
 245         TypeVals.push_back(VE.getTypeID(*I));
 246       AbbrevToUse = StructAbbrev;
 247       break;
 248     }
 249     case Type::ArrayTyID: {
 250       const ArrayType *AT = cast<ArrayType>(T);
 251       // ARRAY: [numelts, eltty]
 252       Code = bitc::TYPE_CODE_ARRAY;
 253       TypeVals.push_back(AT->getNumElements());
 254       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 255       AbbrevToUse = ArrayAbbrev;
 256       break;
 257     }
 258     case Type::VectorTyID: {
 259       const VectorType *VT = cast<VectorType>(T);
 260       // VECTOR [numelts, eltty]
 261       Code = bitc::TYPE_CODE_VECTOR;
 262       TypeVals.push_back(VT->getNumElements());
 263       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 264       break;
 265     }
 266     }
 267
 268     // Emit the finished record.
 269     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 270     TypeVals.clear();
 271   }
 272
 273   Stream.ExitBlock();
 274 }
 275
 276 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 277   switch (GV->getLinkage()) {
 278   default: assert(0 && "Invalid linkage!");
 279   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 280   case GlobalValue::ExternalLinkage:     return 0;
 281   case GlobalValue::WeakAnyLinkage:      return 1;
 282   case GlobalValue::AppendingLinkage:    return 2;
 283   case GlobalValue::InternalLinkage:     return 3;
 284   case GlobalValue::LinkOnceAnyLinkage:  return 4;
 285   case GlobalValue::DLLImportLinkage:    return 5;
 286   case GlobalValue::DLLExportLinkage:    return 6;
 287   case GlobalValue::ExternalWeakLinkage: return 7;
 288   case GlobalValue::CommonLinkage:       return 8;
 289   case GlobalValue::PrivateLinkage:      return 9;
 290   case GlobalValue::WeakODRLinkage:      return 10;
 291   case GlobalValue::LinkOnceODRLinkage:  return 11;
 292   case GlobalValue::AvailableExternallyLinkage:  return 12;
 293   }
 294 }
 295
 296 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 297   switch (GV->getVisibility()) {
 298   default: assert(0 && "Invalid visibility!");
 299   case GlobalValue::DefaultVisibility:   return 0;
 300   case GlobalValue::HiddenVisibility:    return 1;
 301   case GlobalValue::ProtectedVisibility: return 2;
 302   }
 303 }
 304
 305 // Emit top-level description of module, including target triple, inline asm,
 306 // descriptors for global variables, and function prototype info.
 307 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 308                             BitstreamWriter &Stream) {
 309   // Emit the list of dependent libraries for the Module.
 310   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 311     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 312
 313   // Emit various pieces of data attached to a module.
 314   if (!M->getTargetTriple().empty())
 315     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 316                       0/*TODO*/, Stream);
 317   if (!M->getDataLayout().empty())
 318     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 319                       0/*TODO*/, Stream);
 320   if (!M->getModuleInlineAsm().empty())
 321     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 322                       0/*TODO*/, Stream);
 323
 324   // Emit information about sections and GC, computing how many there are. Also
 325   // compute the maximum alignment value.
 326   std::map<std::string, unsigned> SectionMap;
 327   std::map<std::string, unsigned> GCMap;
 328   unsigned MaxAlignment = 0;
 329   unsigned MaxGlobalType = 0;
 330   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 331        GV != E; ++GV) {
 332     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 333     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 334
 335     if (!GV->hasSection()) continue;
 336     // Give section names unique ID's.
 337     unsigned &Entry = SectionMap[GV->getSection()];
 338     if (Entry != 0) continue;
 339     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 340                       0/*TODO*/, Stream);
 341     Entry = SectionMap.size();
 342   }
 343   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 344     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 345     if (F->hasSection()) {
 346       // Give section names unique ID's.
 347       unsigned &Entry = SectionMap[F->getSection()];
 348       if (!Entry) {
 349         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 350                           0/*TODO*/, Stream);
 351         Entry = SectionMap.size();
 352       }
 353     }
 354     if (F->hasGC()) {
 355       // Same for GC names.
 356       unsigned &Entry = GCMap[F->getGC()];
 357       if (!Entry) {
 358         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 359                           0/*TODO*/, Stream);
 360         Entry = GCMap.size();
 361       }
 362     }
 363   }
 364
 365   // Emit abbrev for globals, now that we know # sections and max alignment.
 366   unsigned SimpleGVarAbbrev = 0;
 367   if (!M->global_empty()) {
 368     // Add an abbrev for common globals with no visibility or thread localness.
 369     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 370     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 372                               Log2_32_Ceil(MaxGlobalType+1)));
 373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 376     if (MaxAlignment == 0)                                      // Alignment.
 377       Abbv->Add(BitCodeAbbrevOp(0));
 378     else {
 379       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 380       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 381                                Log2_32_Ceil(MaxEncAlignment+1)));
 382     }
 383     if (SectionMap.empty())                                    // Section.
 384       Abbv->Add(BitCodeAbbrevOp(0));
 385     else
 386       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 387                                Log2_32_Ceil(SectionMap.size()+1)));
 388     // Don't bother emitting vis + thread local.
 389     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 390   }
 391
 392   // Emit the global variable information.
 393   SmallVector<unsigned, 64> Vals;
 394   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 395        GV != E; ++GV) {
 396     unsigned AbbrevToUse = 0;
 397
 398     // GLOBALVAR: [type, isconst, initid,
 399     //             linkage, alignment, section, visibility, threadlocal]
 400     Vals.push_back(VE.getTypeID(GV->getType()));
 401     Vals.push_back(GV->isConstant());
 402     Vals.push_back(GV->isDeclaration() ? 0 :
 403                    (VE.getValueID(GV->getInitializer()) + 1));
 404     Vals.push_back(getEncodedLinkage(GV));
 405     Vals.push_back(Log2_32(GV->getAlignment())+1);
 406     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 407     if (GV->isThreadLocal() ||
 408         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 409       Vals.push_back(getEncodedVisibility(GV));
 410       Vals.push_back(GV->isThreadLocal());
 411     } else {
 412       AbbrevToUse = SimpleGVarAbbrev;
 413     }
 414
 415     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 416     Vals.clear();
 417   }
 418
 419   // Emit the function proto information.
 420   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 421     // FUNCTION:  [type, callingconv, isproto, paramattr,
 422     //             linkage, alignment, section, visibility, gc]
 423     Vals.push_back(VE.getTypeID(F->getType()));
 424     Vals.push_back(F->getCallingConv());
 425     Vals.push_back(F->isDeclaration());
 426     Vals.push_back(getEncodedLinkage(F));
 427     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 428     Vals.push_back(Log2_32(F->getAlignment())+1);
 429     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 430     Vals.push_back(getEncodedVisibility(F));
 431     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 432
 433     unsigned AbbrevToUse = 0;
 434     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 435     Vals.clear();
 436   }
 437
 438
 439   // Emit the alias information.
 440   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 441        AI != E; ++AI) {
 442     Vals.push_back(VE.getTypeID(AI->getType()));
 443     Vals.push_back(VE.getValueID(AI->getAliasee()));
 444     Vals.push_back(getEncodedLinkage(AI));
 445     Vals.push_back(getEncodedVisibility(AI));
 446     unsigned AbbrevToUse = 0;
 447     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 448     Vals.clear();
 449   }
 450 }
 451
 452
 453 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 454                            const ValueEnumerator &VE,
 455                            BitstreamWriter &Stream, bool isGlobal) {
 456   if (FirstVal == LastVal) return;
 457
 458   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 459
 460   unsigned AggregateAbbrev = 0;
 461   unsigned String8Abbrev = 0;
 462   unsigned CString7Abbrev = 0;
 463   unsigned CString6Abbrev = 0;
 464   unsigned MDString8Abbrev = 0;
 465   unsigned MDString6Abbrev = 0;
 466   // If this is a constant pool for the module, emit module-specific abbrevs.
 467   if (isGlobal) {
 468     // Abbrev for CST_CODE_AGGREGATE.
 469     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 470     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 473     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 474
 475     // Abbrev for CST_CODE_STRING.
 476     Abbv = new BitCodeAbbrev();
 477     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 478     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 479     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 480     String8Abbrev = Stream.EmitAbbrev(Abbv);
 481     // Abbrev for CST_CODE_CSTRING.
 482     Abbv = new BitCodeAbbrev();
 483     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 486     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 487     // Abbrev for CST_CODE_CSTRING.
 488     Abbv = new BitCodeAbbrev();
 489     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 492     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 493
 494     // Abbrev for CST_CODE_MDSTRING.
 495     Abbv = new BitCodeAbbrev();
 496     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 499     MDString8Abbrev = Stream.EmitAbbrev(Abbv);
 500     // Abbrev for CST_CODE_MDSTRING.
 501     Abbv = new BitCodeAbbrev();
 502     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 505     MDString6Abbrev = Stream.EmitAbbrev(Abbv);
 506   }
 507
 508   SmallVector<uint64_t, 64> Record;
 509
 510   const ValueEnumerator::ValueList &Vals = VE.getValues();
 511   const Type *LastTy = 0;
 512   for (unsigned i = FirstVal; i != LastVal; ++i) {
 513     const Value *V = Vals[i].first;
 514     // If we need to switch types, do so now.
 515     if (V->getType() != LastTy) {
 516       LastTy = V->getType();
 517       Record.push_back(VE.getTypeID(LastTy));
 518       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 519                         CONSTANTS_SETTYPE_ABBREV);
 520       Record.clear();
 521     }
 522
 523     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 524       Record.push_back(unsigned(IA->hasSideEffects()));
 525
 526       // Add the asm string.
 527       const std::string &AsmStr = IA->getAsmString();
 528       Record.push_back(AsmStr.size());
 529       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 530         Record.push_back(AsmStr[i]);
 531
 532       // Add the constraint string.
 533       const std::string &ConstraintStr = IA->getConstraintString();
 534       Record.push_back(ConstraintStr.size());
 535       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 536         Record.push_back(ConstraintStr[i]);
 537       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 538       Record.clear();
 539       continue;
 540     }
 541     const Constant *C = cast<Constant>(V);
 542     unsigned Code = -1U;
 543     unsigned AbbrevToUse = 0;
 544     if (C->isNullValue()) {
 545       Code = bitc::CST_CODE_NULL;
 546     } else if (isa<UndefValue>(C)) {
 547       Code = bitc::CST_CODE_UNDEF;
 548     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 549       if (IV->getBitWidth() <= 64) {
 550         int64_t V = IV->getSExtValue();
 551         if (V >= 0)
 552           Record.push_back(V << 1);
 553         else
 554           Record.push_back((-V << 1) | 1);
 555         Code = bitc::CST_CODE_INTEGER;
 556         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 557       } else {                             // Wide integers, > 64 bits in size.
 558         // We have an arbitrary precision integer value to write whose
 559         // bit width is > 64. However, in canonical unsigned integer
 560         // format it is likely that the high bits are going to be zero.
 561         // So, we only write the number of active words.
 562         unsigned NWords = IV->getValue().getActiveWords();
 563         const uint64_t *RawWords = IV->getValue().getRawData();
 564         for (unsigned i = 0; i != NWords; ++i) {
 565           int64_t V = RawWords[i];
 566           if (V >= 0)
 567             Record.push_back(V << 1);
 568           else
 569             Record.push_back((-V << 1) | 1);
 570         }
 571         Code = bitc::CST_CODE_WIDE_INTEGER;
 572       }
 573     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 574       Code = bitc::CST_CODE_FLOAT;
 575       const Type *Ty = CFP->getType();
 576       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 577         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 578       } else if (Ty == Type::X86_FP80Ty) {
 579         // api needed to prevent premature destruction
 580         // bits are not in the same order as a normal i80 APInt, compensate.
 581         APInt api = CFP->getValueAPF().bitcastToAPInt();
 582         const uint64_t *p = api.getRawData();
 583         Record.push_back((p[1] << 48) | (p[0] >> 16));
 584         Record.push_back(p[0] & 0xffffLL);
 585       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 586         APInt api = CFP->getValueAPF().bitcastToAPInt();
 587         const uint64_t *p = api.getRawData();
 588         Record.push_back(p[0]);
 589         Record.push_back(p[1]);
 590       } else {
 591         assert (0 && "Unknown FP type!");
 592       }
 593     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 594       // Emit constant strings specially.
 595       unsigned NumOps = C->getNumOperands();
 596       // If this is a null-terminated string, use the denser CSTRING encoding.
 597       if (C->getOperand(NumOps-1)->isNullValue()) {
 598         Code = bitc::CST_CODE_CSTRING;
 599         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 600       } else {
 601         Code = bitc::CST_CODE_STRING;
 602         AbbrevToUse = String8Abbrev;
 603       }
 604       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 605       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 606       for (unsigned i = 0; i != NumOps; ++i) {
 607         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 608         Record.push_back(V);
 609         isCStr7 &= (V & 128) == 0;
 610         if (isCStrChar6)
 611           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 612       }
 613
 614       if (isCStrChar6)
 615         AbbrevToUse = CString6Abbrev;
 616       else if (isCStr7)
 617         AbbrevToUse = CString7Abbrev;
 618     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 619                isa<ConstantVector>(V)) {
 620       Code = bitc::CST_CODE_AGGREGATE;
 621       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 622         Record.push_back(VE.getValueID(C->getOperand(i)));
 623       AbbrevToUse = AggregateAbbrev;
 624     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 625       switch (CE->getOpcode()) {
 626       default:
 627         if (Instruction::isCast(CE->getOpcode())) {
 628           Code = bitc::CST_CODE_CE_CAST;
 629           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 630           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 631           Record.push_back(VE.getValueID(C->getOperand(0)));
 632           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 633         } else {
 634           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 635           Code = bitc::CST_CODE_CE_BINOP;
 636           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 637           Record.push_back(VE.getValueID(C->getOperand(0)));
 638           Record.push_back(VE.getValueID(C->getOperand(1)));
 639         }
 640         break;
 641       case Instruction::GetElementPtr:
 642         Code = bitc::CST_CODE_CE_GEP;
 643         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 644           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 645           Record.push_back(VE.getValueID(C->getOperand(i)));
 646         }
 647         break;
 648       case Instruction::Select:
 649         Code = bitc::CST_CODE_CE_SELECT;
 650         Record.push_back(VE.getValueID(C->getOperand(0)));
 651         Record.push_back(VE.getValueID(C->getOperand(1)));
 652         Record.push_back(VE.getValueID(C->getOperand(2)));
 653         break;
 654       case Instruction::ExtractElement:
 655         Code = bitc::CST_CODE_CE_EXTRACTELT;
 656         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 657         Record.push_back(VE.getValueID(C->getOperand(0)));
 658         Record.push_back(VE.getValueID(C->getOperand(1)));
 659         break;
 660       case Instruction::InsertElement:
 661         Code = bitc::CST_CODE_CE_INSERTELT;
 662         Record.push_back(VE.getValueID(C->getOperand(0)));
 663         Record.push_back(VE.getValueID(C->getOperand(1)));
 664         Record.push_back(VE.getValueID(C->getOperand(2)));
 665         break;
 666       case Instruction::ShuffleVector:
 667         // If the return type and argument types are the same, this is a
 668         // standard shufflevector instruction.  If the types are different,
 669         // then the shuffle is widening or truncating the input vectors, and
 670         // the argument type must also be encoded.
 671         if (C->getType() == C->getOperand(0)->getType()) {
 672           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 673         } else {
 674           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 675           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 676         }
 677         Record.push_back(VE.getValueID(C->getOperand(0)));
 678         Record.push_back(VE.getValueID(C->getOperand(1)));
 679         Record.push_back(VE.getValueID(C->getOperand(2)));
 680         break;
 681       case Instruction::ICmp:
 682       case Instruction::FCmp:
 683       case Instruction::VICmp:
 684       case Instruction::VFCmp:
 685         if (isa<VectorType>(C->getOperand(0)->getType())
 686             && (CE->getOpcode() == Instruction::ICmp
 687                 || CE->getOpcode() == Instruction::FCmp)) {
 688           // compare returning vector of Int1Ty
 689           assert(0 && "Unsupported constant!");
 690         } else {
 691           Code = bitc::CST_CODE_CE_CMP;
 692         }
 693         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 694         Record.push_back(VE.getValueID(C->getOperand(0)));
 695         Record.push_back(VE.getValueID(C->getOperand(1)));
 696         Record.push_back(CE->getPredicate());
 697         break;
 698       }
 699     } else if (const MDString *S = dyn_cast<MDString>(C)) {
 700       Code = bitc::CST_CODE_MDSTRING;
 701       AbbrevToUse = MDString6Abbrev;
 702       for (unsigned i = 0, e = S->size(); i != e; ++i) {
 703         char V = S->begin()[i];
 704         Record.push_back(V);
 705
 706         if (!BitCodeAbbrevOp::isChar6(V))
 707           AbbrevToUse = MDString8Abbrev;
 708       }
 709     } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
 710       Code = bitc::CST_CODE_MDNODE;
 711       for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 712         if (N->getElement(i)) {
 713           Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 714           Record.push_back(VE.getValueID(N->getElement(i)));
 715         } else {
 716           Record.push_back(VE.getTypeID(Type::VoidTy));
 717           Record.push_back(0);
 718         }
 719       }
 720     } else {
 721       assert(0 && "Unknown constant!");
 722     }
 723     Stream.EmitRecord(Code, Record, AbbrevToUse);
 724     Record.clear();
 725   }
 726
 727   Stream.ExitBlock();
 728 }
 729
 730 static void WriteModuleConstants(const ValueEnumerator &VE,
 731                                  BitstreamWriter &Stream) {
 732   const ValueEnumerator::ValueList &Vals = VE.getValues();
 733
 734   // Find the first constant to emit, which is the first non-globalvalue value.
 735   // We know globalvalues have been emitted by WriteModuleInfo.
 736   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 737     if (!isa<GlobalValue>(Vals[i].first)) {
 738       WriteConstants(i, Vals.size(), VE, Stream, true);
 739       return;
 740     }
 741   }
 742 }
 743
 744 /// PushValueAndType - The file has to encode both the value and type id for
 745 /// many values, because we need to know what type to create for forward
 746 /// references.  However, most operands are not forward references, so this type
 747 /// field is not needed.
 748 ///
 749 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 750 /// instruction ID, then it is a forward reference, and it also includes the
 751 /// type ID.
 752 static bool PushValueAndType(const Value *V, unsigned InstID,
 753                              SmallVector<unsigned, 64> &Vals,
 754                              ValueEnumerator &VE) {
 755   unsigned ValID = VE.getValueID(V);
 756   Vals.push_back(ValID);
 757   if (ValID >= InstID) {
 758     Vals.push_back(VE.getTypeID(V->getType()));
 759     return true;
 760   }
 761   return false;
 762 }
 763
 764 /// WriteInstruction - Emit an instruction to the specified stream.
 765 static void WriteInstruction(const Instruction &I, unsigned InstID,
 766                              ValueEnumerator &VE, BitstreamWriter &Stream,
 767                              SmallVector<unsigned, 64> &Vals) {
 768   unsigned Code = 0;
 769   unsigned AbbrevToUse = 0;
 770   switch (I.getOpcode()) {
 771   default:
 772     if (Instruction::isCast(I.getOpcode())) {
 773       Code = bitc::FUNC_CODE_INST_CAST;
 774       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 775         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 776       Vals.push_back(VE.getTypeID(I.getType()));
 777       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 778     } else {
 779       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 780       Code = bitc::FUNC_CODE_INST_BINOP;
 781       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 782         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 783       Vals.push_back(VE.getValueID(I.getOperand(1)));
 784       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 785     }
 786     break;
 787
 788   case Instruction::GetElementPtr:
 789     Code = bitc::FUNC_CODE_INST_GEP;
 790     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 791       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 792     break;
 793   case Instruction::ExtractValue: {
 794     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 795     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 796     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 797     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 798       Vals.push_back(*i);
 799     break;
 800   }
 801   case Instruction::InsertValue: {
 802     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 803     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 804     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 805     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 806     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 807       Vals.push_back(*i);
 808     break;
 809   }
 810   case Instruction::Select:
 811     Code = bitc::FUNC_CODE_INST_VSELECT;
 812     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 813     Vals.push_back(VE.getValueID(I.getOperand(2)));
 814     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 815     break;
 816   case Instruction::ExtractElement:
 817     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 818     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 819     Vals.push_back(VE.getValueID(I.getOperand(1)));
 820     break;
 821   case Instruction::InsertElement:
 822     Code = bitc::FUNC_CODE_INST_INSERTELT;
 823     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 824     Vals.push_back(VE.getValueID(I.getOperand(1)));
 825     Vals.push_back(VE.getValueID(I.getOperand(2)));
 826     break;
 827   case Instruction::ShuffleVector:
 828     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 829     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 830     Vals.push_back(VE.getValueID(I.getOperand(1)));
 831     Vals.push_back(VE.getValueID(I.getOperand(2)));
 832     break;
 833   case Instruction::ICmp:
 834   case Instruction::FCmp:
 835   case Instruction::VICmp:
 836   case Instruction::VFCmp:
 837     if (I.getOpcode() == Instruction::ICmp
 838         || I.getOpcode() == Instruction::FCmp) {
 839       // compare returning Int1Ty or vector of Int1Ty
 840       Code = bitc::FUNC_CODE_INST_CMP2;
 841     } else {
 842       Code = bitc::FUNC_CODE_INST_CMP;
 843     }
 844     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 845     Vals.push_back(VE.getValueID(I.getOperand(1)));
 846     Vals.push_back(cast<CmpInst>(I).getPredicate());
 847     break;
 848
 849   case Instruction::Ret:
 850     {
 851       Code = bitc::FUNC_CODE_INST_RET;
 852       unsigned NumOperands = I.getNumOperands();
 853       if (NumOperands == 0)
 854         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 855       else if (NumOperands == 1) {
 856         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 857           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 858       } else {
 859         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 860           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 861       }
 862     }
 863     break;
 864   case Instruction::Br:
 865     {
 866       Code = bitc::FUNC_CODE_INST_BR;
 867       BranchInst &II(cast<BranchInst>(I));
 868       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 869       if (II.isConditional()) {
 870         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 871         Vals.push_back(VE.getValueID(II.getCondition()));
 872       }
 873     }
 874     break;
 875   case Instruction::Switch:
 876     Code = bitc::FUNC_CODE_INST_SWITCH;
 877     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 878     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 879       Vals.push_back(VE.getValueID(I.getOperand(i)));
 880     break;
 881   case Instruction::Invoke: {
 882     const InvokeInst *II = cast<InvokeInst>(&I);
 883     const Value *Callee(II->getCalledValue());
 884     const PointerType *PTy = cast<PointerType>(Callee->getType());
 885     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 886     Code = bitc::FUNC_CODE_INST_INVOKE;
 887
 888     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 889     Vals.push_back(II->getCallingConv());
 890     Vals.push_back(VE.getValueID(II->getNormalDest()));
 891     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 892     PushValueAndType(Callee, InstID, Vals, VE);
 893
 894     // Emit value #'s for the fixed parameters.
 895     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 896       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 897
 898     // Emit type/value pairs for varargs params.
 899     if (FTy->isVarArg()) {
 900       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 901            i != e; ++i)
 902         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 903     }
 904     break;
 905   }
 906   case Instruction::Unwind:
 907     Code = bitc::FUNC_CODE_INST_UNWIND;
 908     break;
 909   case Instruction::Unreachable:
 910     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 911     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 912     break;
 913
 914   case Instruction::PHI:
 915     Code = bitc::FUNC_CODE_INST_PHI;
 916     Vals.push_back(VE.getTypeID(I.getType()));
 917     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 918       Vals.push_back(VE.getValueID(I.getOperand(i)));
 919     break;
 920
 921   case Instruction::Malloc:
 922     Code = bitc::FUNC_CODE_INST_MALLOC;
 923     Vals.push_back(VE.getTypeID(I.getType()));
 924     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 925     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 926     break;
 927
 928   case Instruction::Free:
 929     Code = bitc::FUNC_CODE_INST_FREE;
 930     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 931     break;
 932
 933   case Instruction::Alloca:
 934     Code = bitc::FUNC_CODE_INST_ALLOCA;
 935     Vals.push_back(VE.getTypeID(I.getType()));
 936     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 937     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 938     break;
 939
 940   case Instruction::Load:
 941     Code = bitc::FUNC_CODE_INST_LOAD;
 942     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 943       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 944
 945     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 946     Vals.push_back(cast<LoadInst>(I).isVolatile());
 947     break;
 948   case Instruction::Store:
 949     Code = bitc::FUNC_CODE_INST_STORE2;
 950     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 951     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 952     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 953     Vals.push_back(cast<StoreInst>(I).isVolatile());
 954     break;
 955   case Instruction::Call: {
 956     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 957     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 958
 959     Code = bitc::FUNC_CODE_INST_CALL;
 960
 961     const CallInst *CI = cast<CallInst>(&I);
 962     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 963     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 964     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 965
 966     // Emit value #'s for the fixed parameters.
 967     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 968       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 969
 970     // Emit type/value pairs for varargs params.
 971     if (FTy->isVarArg()) {
 972       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 973       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 974            i != e; ++i)
 975         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 976     }
 977     break;
 978   }
 979   case Instruction::VAArg:
 980     Code = bitc::FUNC_CODE_INST_VAARG;
 981     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 982     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 983     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 984     break;
 985   }
 986
 987   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 988   Vals.clear();
 989 }
 990
 991 // Emit names for globals/functions etc.
 992 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 993                                   const ValueEnumerator &VE,
 994                                   BitstreamWriter &Stream) {
 995   if (VST.empty()) return;
 996   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 997
 998   // FIXME: Set up the abbrev, we know how many values there are!
 999   // FIXME: We know if the type names can use 7-bit ascii.
1000   SmallVector<unsigned, 64> NameVals;
1001
1002   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1003        SI != SE; ++SI) {
1004
1005     const ValueName &Name = *SI;
1006
1007     // Figure out the encoding to use for the name.
1008     bool is7Bit = true;
1009     bool isChar6 = true;
1010     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1011          C != E; ++C) {
1012       if (isChar6)
1013         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1014       if ((unsigned char)*C & 128) {
1015         is7Bit = false;
1016         break;  // don't bother scanning the rest.
1017       }
1018     }
1019
1020     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1021
1022     // VST_ENTRY:   [valueid, namechar x N]
1023     // VST_BBENTRY: [bbid, namechar x N]
1024     unsigned Code;
1025     if (isa<BasicBlock>(SI->getValue())) {
1026       Code = bitc::VST_CODE_BBENTRY;
1027       if (isChar6)
1028         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1029     } else {
1030       Code = bitc::VST_CODE_ENTRY;
1031       if (isChar6)
1032         AbbrevToUse = VST_ENTRY_6_ABBREV;
1033       else if (is7Bit)
1034         AbbrevToUse = VST_ENTRY_7_ABBREV;
1035     }
1036
1037     NameVals.push_back(VE.getValueID(SI->getValue()));
1038     for (const char *P = Name.getKeyData(),
1039          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1040       NameVals.push_back((unsigned char)*P);
1041
1042     // Emit the finished record.
1043     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1044     NameVals.clear();
1045   }
1046   Stream.ExitBlock();
1047 }
1048
1049 /// WriteFunction - Emit a function body to the module stream.
1050 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1051                           BitstreamWriter &Stream) {
1052   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1053   VE.incorporateFunction(F);
1054
1055   SmallVector<unsigned, 64> Vals;
1056
1057   // Emit the number of basic blocks, so the reader can create them ahead of
1058   // time.
1059   Vals.push_back(VE.getBasicBlocks().size());
1060   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1061   Vals.clear();
1062
1063   // If there are function-local constants, emit them now.
1064   unsigned CstStart, CstEnd;
1065   VE.getFunctionConstantRange(CstStart, CstEnd);
1066   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1067
1068   // Keep a running idea of what the instruction ID is.
1069   unsigned InstID = CstEnd;
1070
1071   // Finally, emit all the instructions, in order.
1072   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1073     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1074          I != E; ++I) {
1075       WriteInstruction(*I, InstID, VE, Stream, Vals);
1076       if (I->getType() != Type::VoidTy)
1077         ++InstID;
1078     }
1079
1080   // Emit names for all the instructions etc.
1081   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1082
1083   VE.purgeFunction();
1084   Stream.ExitBlock();
1085 }
1086
1087 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1088 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1089                                  const ValueEnumerator &VE,
1090                                  BitstreamWriter &Stream) {
1091   if (TST.empty()) return;
1092
1093   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1094
1095   // 7-bit fixed width VST_CODE_ENTRY strings.
1096   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1097   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1099                             Log2_32_Ceil(VE.getTypes().size()+1)));
1100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1102   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1103
1104   SmallVector<unsigned, 64> NameVals;
1105
1106   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1107        TI != TE; ++TI) {
1108     // TST_ENTRY: [typeid, namechar x N]
1109     NameVals.push_back(VE.getTypeID(TI->second));
1110
1111     const std::string &Str = TI->first;
1112     bool is7Bit = true;
1113     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1114       NameVals.push_back((unsigned char)Str[i]);
1115       if (Str[i] & 128)
1116         is7Bit = false;
1117     }
1118
1119     // Emit the finished record.
1120     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1121     NameVals.clear();
1122   }
1123
1124   Stream.ExitBlock();
1125 }
1126
1127 // Emit blockinfo, which defines the standard abbreviations etc.
1128 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1129   // We only want to emit block info records for blocks that have multiple
1130   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1131   // blocks can defined their abbrevs inline.
1132   Stream.EnterBlockInfoBlock(2);
1133
1134   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1135     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1138     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1139     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1140     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1141                                    Abbv) != VST_ENTRY_8_ABBREV)
1142       assert(0 && "Unexpected abbrev ordering!");
1143   }
1144
1145   { // 7-bit fixed width VST_ENTRY strings.
1146     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1147     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1151     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1152                                    Abbv) != VST_ENTRY_7_ABBREV)
1153       assert(0 && "Unexpected abbrev ordering!");
1154   }
1155   { // 6-bit char6 VST_ENTRY strings.
1156     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1157     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1159     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1161     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1162                                    Abbv) != VST_ENTRY_6_ABBREV)
1163       assert(0 && "Unexpected abbrev ordering!");
1164   }
1165   { // 6-bit char6 VST_BBENTRY strings.
1166     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1167     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1170     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1171     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1172                                    Abbv) != VST_BBENTRY_6_ABBREV)
1173       assert(0 && "Unexpected abbrev ordering!");
1174   }
1175
1176
1177
1178   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1179     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1180     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1181     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1182                               Log2_32_Ceil(VE.getTypes().size()+1)));
1183     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1184                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1185       assert(0 && "Unexpected abbrev ordering!");
1186   }
1187
1188   { // INTEGER abbrev for CONSTANTS_BLOCK.
1189     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1190     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1192     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1193                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1194       assert(0 && "Unexpected abbrev ordering!");
1195   }
1196
1197   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1198     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1199     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1201     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1202                               Log2_32_Ceil(VE.getTypes().size()+1)));
1203     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1204
1205     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1206                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1207       assert(0 && "Unexpected abbrev ordering!");
1208   }
1209   { // NULL abbrev for CONSTANTS_BLOCK.
1210     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1211     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1212     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1213                                    Abbv) != CONSTANTS_NULL_Abbrev)
1214       assert(0 && "Unexpected abbrev ordering!");
1215   }
1216
1217   // FIXME: This should only use space for first class types!
1218
1219   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1220     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1221     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1222     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1225     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1226                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1227       assert(0 && "Unexpected abbrev ordering!");
1228   }
1229   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1230     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1231     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1235     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1236                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1237       assert(0 && "Unexpected abbrev ordering!");
1238   }
1239   { // INST_CAST abbrev for FUNCTION_BLOCK.
1240     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1241     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1244                               Log2_32_Ceil(VE.getTypes().size()+1)));
1245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1246     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1247                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1248       assert(0 && "Unexpected abbrev ordering!");
1249   }
1250
1251   { // INST_RET abbrev for FUNCTION_BLOCK.
1252     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1253     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1254     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1255                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1256       assert(0 && "Unexpected abbrev ordering!");
1257   }
1258   { // INST_RET abbrev for FUNCTION_BLOCK.
1259     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1260     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1262     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1263                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1264       assert(0 && "Unexpected abbrev ordering!");
1265   }
1266   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1267     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1268     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1269     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1270                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1271       assert(0 && "Unexpected abbrev ordering!");
1272   }
1273
1274   Stream.ExitBlock();
1275 }
1276
1277
1278 /// WriteModule - Emit the specified module to the bitstream.
1279 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1280   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1281
1282   // Emit the version number if it is non-zero.
1283   if (CurVersion) {
1284     SmallVector<unsigned, 1> Vals;
1285     Vals.push_back(CurVersion);
1286     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1287   }
1288
1289   // Analyze the module, enumerating globals, functions, etc.
1290   ValueEnumerator VE(M);
1291
1292   // Emit blockinfo, which defines the standard abbreviations etc.
1293   WriteBlockInfo(VE, Stream);
1294
1295   // Emit information about parameter attributes.
1296   WriteAttributeTable(VE, Stream);
1297
1298   // Emit information describing all of the types in the module.
1299   WriteTypeTable(VE, Stream);
1300
1301   // Emit top-level description of module, including target triple, inline asm,
1302   // descriptors for global variables, and function prototype info.
1303   WriteModuleInfo(M, VE, Stream);
1304
1305   // Emit constants.
1306   WriteModuleConstants(VE, Stream);
1307
1308   // If we have any aggregate values in the value table, purge them - these can
1309   // only be used to initialize global variables.  Doing so makes the value
1310   // namespace smaller for code in functions.
1311   int NumNonAggregates = VE.PurgeAggregateValues();
1312   if (NumNonAggregates != -1) {
1313     SmallVector<unsigned, 1> Vals;
1314     Vals.push_back(NumNonAggregates);
1315     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1316   }
1317
1318   // Emit function bodies.
1319   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1320     if (!I->isDeclaration())
1321       WriteFunction(*I, VE, Stream);
1322
1323   // Emit the type symbol table information.
1324   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1325
1326   // Emit names for globals/functions etc.
1327   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1328
1329   Stream.ExitBlock();
1330 }
1331
1332 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1333 /// header and trailer to make it compatible with the system archiver.  To do
1334 /// this we emit the following header, and then emit a trailer that pads the
1335 /// file out to be a multiple of 16 bytes.
1336 ///
1337 /// struct bc_header {
1338 ///   uint32_t Magic;         // 0x0B17C0DE
1339 ///   uint32_t Version;       // Version, currently always 0.
1340 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1341 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1342 ///   uint32_t CPUType;       // CPU specifier.
1343 ///   ... potentially more later ...
1344 /// };
1345 enum {
1346   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1347   DarwinBCHeaderSize = 5*4
1348 };
1349
1350 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1351                                const std::string &TT) {
1352   unsigned CPUType = ~0U;
1353
1354   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1355   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1356   // specific constants here because they are implicitly part of the Darwin ABI.
1357   enum {
1358     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1359     DARWIN_CPU_TYPE_X86        = 7,
1360     DARWIN_CPU_TYPE_POWERPC    = 18
1361   };
1362
1363   if (TT.find("x86_64-") == 0)
1364     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1365   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1366            TT[4] == '-' && TT[1] - '3' < 6)
1367     CPUType = DARWIN_CPU_TYPE_X86;
1368   else if (TT.find("powerpc-") == 0)
1369     CPUType = DARWIN_CPU_TYPE_POWERPC;
1370   else if (TT.find("powerpc64-") == 0)
1371     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1372
1373   // Traditional Bitcode starts after header.
1374   unsigned BCOffset = DarwinBCHeaderSize;
1375
1376   Stream.Emit(0x0B17C0DE, 32);
1377   Stream.Emit(0         , 32);  // Version.
1378   Stream.Emit(BCOffset  , 32);
1379   Stream.Emit(0         , 32);  // Filled in later.
1380   Stream.Emit(CPUType   , 32);
1381 }
1382
1383 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1384 /// finalize the header.
1385 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1386   // Update the size field in the header.
1387   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1388
1389   // If the file is not a multiple of 16 bytes, insert dummy padding.
1390   while (BufferSize & 15) {
1391     Stream.Emit(0, 8);
1392     ++BufferSize;
1393   }
1394 }
1395
1396
1397 /// WriteBitcodeToFile - Write the specified module to the specified output
1398 /// stream.
1399 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1400   raw_os_ostream RawOut(Out);
1401   // If writing to stdout, set binary mode.
1402   if (llvm::cout == Out)
1403     sys::Program::ChangeStdoutToBinary();
1404   WriteBitcodeToFile(M, RawOut);
1405 }
1406
1407 /// WriteBitcodeToFile - Write the specified module to the specified output
1408 /// stream.
1409 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1410   std::vector<unsigned char> Buffer;
1411   BitstreamWriter Stream(Buffer);
1412
1413   Buffer.reserve(256*1024);
1414
1415   WriteBitcodeToStream( M, Stream );
1416
1417   // If writing to stdout, set binary mode.
1418   if (&llvm::outs() == &Out)
1419     sys::Program::ChangeStdoutToBinary();
1420
1421   // Write the generated bitstream to "Out".
1422   Out.write((char*)&Buffer.front(), Buffer.size());
1423
1424   // Make sure it hits disk now.
1425   Out.flush();
1426 }
1427
1428 /// WriteBitcodeToStream - Write the specified module to the specified output
1429 /// stream.
1430 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1431   // If this is darwin, emit a file header and trailer if needed.
1432   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1433   if (isDarwin)
1434     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1435
1436   // Emit the file header.
1437   Stream.Emit((unsigned)'B', 8);
1438   Stream.Emit((unsigned)'C', 8);
1439   Stream.Emit(0x0, 4);
1440   Stream.Emit(0xC, 4);
1441   Stream.Emit(0xE, 4);
1442   Stream.Emit(0xD, 4);
1443
1444   // Emit the module.
1445   WriteModule(M, Stream);
1446
1447   if (isDarwin)
1448     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1449 }