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