lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Operator.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/ADT/Triple.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/Support/Program.h"
  31 #include <cctype>
  32 #include <map>
  33 using namespace llvm;
  34
  35 static cl::opt<bool>
  36 EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
  37                               cl::desc("Turn on experimental support for "
  38                                        "use-list order preservation."),
  39                               cl::init(false), cl::Hidden);
  40
  41 /// These are manifest constants used by the bitcode writer. They do not need to
  42 /// be kept in sync with the reader, but need to be consistent within this file.
  43 enum {
  44   CurVersion = 0,
  45
  46   // VALUE_SYMTAB_BLOCK abbrev id's.
  47   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   VST_ENTRY_7_ABBREV,
  49   VST_ENTRY_6_ABBREV,
  50   VST_BBENTRY_6_ABBREV,
  51
  52   // CONSTANTS_BLOCK abbrev id's.
  53   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   CONSTANTS_INTEGER_ABBREV,
  55   CONSTANTS_CE_CAST_Abbrev,
  56   CONSTANTS_NULL_Abbrev,
  57
  58   // FUNCTION_BLOCK abbrev id's.
  59   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  60   FUNCTION_INST_BINOP_ABBREV,
  61   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  62   FUNCTION_INST_CAST_ABBREV,
  63   FUNCTION_INST_RET_VOID_ABBREV,
  64   FUNCTION_INST_RET_VAL_ABBREV,
  65   FUNCTION_INST_UNREACHABLE_ABBREV,
  66
  67   // SwitchInst Magic
  68   SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
  69 };
  70
  71 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  72   switch (Opcode) {
  73   default: llvm_unreachable("Unknown cast instruction!");
  74   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  75   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  76   case Instruction::SExt    : return bitc::CAST_SEXT;
  77   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  78   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  79   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  80   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  81   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  82   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  83   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  84   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  85   case Instruction::BitCast : return bitc::CAST_BITCAST;
  86   }
  87 }
  88
  89 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  90   switch (Opcode) {
  91   default: llvm_unreachable("Unknown binary instruction!");
  92   case Instruction::Add:
  93   case Instruction::FAdd: return bitc::BINOP_ADD;
  94   case Instruction::Sub:
  95   case Instruction::FSub: return bitc::BINOP_SUB;
  96   case Instruction::Mul:
  97   case Instruction::FMul: return bitc::BINOP_MUL;
  98   case Instruction::UDiv: return bitc::BINOP_UDIV;
  99   case Instruction::FDiv:
 100   case Instruction::SDiv: return bitc::BINOP_SDIV;
 101   case Instruction::URem: return bitc::BINOP_UREM;
 102   case Instruction::FRem:
 103   case Instruction::SRem: return bitc::BINOP_SREM;
 104   case Instruction::Shl:  return bitc::BINOP_SHL;
 105   case Instruction::LShr: return bitc::BINOP_LSHR;
 106   case Instruction::AShr: return bitc::BINOP_ASHR;
 107   case Instruction::And:  return bitc::BINOP_AND;
 108   case Instruction::Or:   return bitc::BINOP_OR;
 109   case Instruction::Xor:  return bitc::BINOP_XOR;
 110   }
 111 }
 112
 113 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 114   switch (Op) {
 115   default: llvm_unreachable("Unknown RMW operation!");
 116   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 117   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 118   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 119   case AtomicRMWInst::And: return bitc::RMW_AND;
 120   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 121   case AtomicRMWInst::Or: return bitc::RMW_OR;
 122   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 123   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 124   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 125   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 126   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 127   }
 128 }
 129
 130 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 131   switch (Ordering) {
 132   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 133   case Unordered: return bitc::ORDERING_UNORDERED;
 134   case Monotonic: return bitc::ORDERING_MONOTONIC;
 135   case Acquire: return bitc::ORDERING_ACQUIRE;
 136   case Release: return bitc::ORDERING_RELEASE;
 137   case AcquireRelease: return bitc::ORDERING_ACQREL;
 138   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 139   }
 140   llvm_unreachable("Invalid ordering");
 141 }
 142
 143 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 144   switch (SynchScope) {
 145   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 146   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 147   }
 148   llvm_unreachable("Invalid synch scope");
 149 }
 150
 151 static void WriteStringRecord(unsigned Code, StringRef Str,
 152                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 153   SmallVector<unsigned, 64> Vals;
 154
 155   // Code: [strchar x N]
 156   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 157     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 158       AbbrevToUse = 0;
 159     Vals.push_back(Str[i]);
 160   }
 161
 162   // Emit the finished record.
 163   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 164 }
 165
 166 // Emit information about parameter attributes.
 167 static void WriteAttributeTable(const ValueEnumerator &VE,
 168                                 BitstreamWriter &Stream) {
 169   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 170   if (Attrs.empty()) return;
 171
 172   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 173
 174   SmallVector<uint64_t, 64> Record;
 175   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 176     const AttrListPtr &A = Attrs[i];
 177     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 178       const AttributeWithIndex &PAWI = A.getSlot(i);
 179       Record.push_back(PAWI.Index);
 180       Record.push_back(Attribute::encodeLLVMAttributesForBitcode(PAWI.Attrs));
 181     }
 182
 183     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 184     Record.clear();
 185   }
 186
 187   Stream.ExitBlock();
 188 }
 189
 190 /// WriteTypeTable - Write out the type table for a module.
 191 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 192   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 193
 194   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 195   SmallVector<uint64_t, 64> TypeVals;
 196
 197   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 198
 199   // Abbrev for TYPE_CODE_POINTER.
 200   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 201   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 203   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 204   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 205
 206   // Abbrev for TYPE_CODE_FUNCTION.
 207   Abbv = new BitCodeAbbrev();
 208   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 211   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 212
 213   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 214
 215   // Abbrev for TYPE_CODE_STRUCT_ANON.
 216   Abbv = new BitCodeAbbrev();
 217   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 219   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 221
 222   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 223
 224   // Abbrev for TYPE_CODE_STRUCT_NAME.
 225   Abbv = new BitCodeAbbrev();
 226   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 227   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 229   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 230
 231   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 232   Abbv = new BitCodeAbbrev();
 233   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 234   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 237
 238   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 239
 240   // Abbrev for TYPE_CODE_ARRAY.
 241   Abbv = new BitCodeAbbrev();
 242   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 243   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 244   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 245
 246   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 247
 248   // Emit an entry count so the reader can reserve space.
 249   TypeVals.push_back(TypeList.size());
 250   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 251   TypeVals.clear();
 252
 253   // Loop over all of the types, emitting each in turn.
 254   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 255     Type *T = TypeList[i];
 256     int AbbrevToUse = 0;
 257     unsigned Code = 0;
 258
 259     switch (T->getTypeID()) {
 260     default: llvm_unreachable("Unknown type!");
 261     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
 262     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;   break;
 263     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
 264     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
 265     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
 266     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128; break;
 267     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 268     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;  break;
 269     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA; break;
 270     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX; break;
 271     case Type::IntegerTyID:
 272       // INTEGER: [width]
 273       Code = bitc::TYPE_CODE_INTEGER;
 274       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 275       break;
 276     case Type::PointerTyID: {
 277       PointerType *PTy = cast<PointerType>(T);
 278       // POINTER: [pointee type, address space]
 279       Code = bitc::TYPE_CODE_POINTER;
 280       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 281       unsigned AddressSpace = PTy->getAddressSpace();
 282       TypeVals.push_back(AddressSpace);
 283       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 284       break;
 285     }
 286     case Type::FunctionTyID: {
 287       FunctionType *FT = cast<FunctionType>(T);
 288       // FUNCTION: [isvararg, retty, paramty x N]
 289       Code = bitc::TYPE_CODE_FUNCTION;
 290       TypeVals.push_back(FT->isVarArg());
 291       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 292       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 293         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 294       AbbrevToUse = FunctionAbbrev;
 295       break;
 296     }
 297     case Type::StructTyID: {
 298       StructType *ST = cast<StructType>(T);
 299       // STRUCT: [ispacked, eltty x N]
 300       TypeVals.push_back(ST->isPacked());
 301       // Output all of the element types.
 302       for (StructType::element_iterator I = ST->element_begin(),
 303            E = ST->element_end(); I != E; ++I)
 304         TypeVals.push_back(VE.getTypeID(*I));
 305
 306       if (ST->isLiteral()) {
 307         Code = bitc::TYPE_CODE_STRUCT_ANON;
 308         AbbrevToUse = StructAnonAbbrev;
 309       } else {
 310         if (ST->isOpaque()) {
 311           Code = bitc::TYPE_CODE_OPAQUE;
 312         } else {
 313           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 314           AbbrevToUse = StructNamedAbbrev;
 315         }
 316
 317         // Emit the name if it is present.
 318         if (!ST->getName().empty())
 319           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 320                             StructNameAbbrev, Stream);
 321       }
 322       break;
 323     }
 324     case Type::ArrayTyID: {
 325       ArrayType *AT = cast<ArrayType>(T);
 326       // ARRAY: [numelts, eltty]
 327       Code = bitc::TYPE_CODE_ARRAY;
 328       TypeVals.push_back(AT->getNumElements());
 329       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 330       AbbrevToUse = ArrayAbbrev;
 331       break;
 332     }
 333     case Type::VectorTyID: {
 334       VectorType *VT = cast<VectorType>(T);
 335       // VECTOR [numelts, eltty]
 336       Code = bitc::TYPE_CODE_VECTOR;
 337       TypeVals.push_back(VT->getNumElements());
 338       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 339       break;
 340     }
 341     }
 342
 343     // Emit the finished record.
 344     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 345     TypeVals.clear();
 346   }
 347
 348   Stream.ExitBlock();
 349 }
 350
 351 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 352   switch (GV->getLinkage()) {
 353   case GlobalValue::ExternalLinkage:                 return 0;
 354   case GlobalValue::WeakAnyLinkage:                  return 1;
 355   case GlobalValue::AppendingLinkage:                return 2;
 356   case GlobalValue::InternalLinkage:                 return 3;
 357   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 358   case GlobalValue::DLLImportLinkage:                return 5;
 359   case GlobalValue::DLLExportLinkage:                return 6;
 360   case GlobalValue::ExternalWeakLinkage:             return 7;
 361   case GlobalValue::CommonLinkage:                   return 8;
 362   case GlobalValue::PrivateLinkage:                  return 9;
 363   case GlobalValue::WeakODRLinkage:                  return 10;
 364   case GlobalValue::LinkOnceODRLinkage:              return 11;
 365   case GlobalValue::AvailableExternallyLinkage:      return 12;
 366   case GlobalValue::LinkerPrivateLinkage:            return 13;
 367   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 368   case GlobalValue::LinkOnceODRAutoHideLinkage:      return 15;
 369   }
 370   llvm_unreachable("Invalid linkage");
 371 }
 372
 373 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 374   switch (GV->getVisibility()) {
 375   case GlobalValue::DefaultVisibility:   return 0;
 376   case GlobalValue::HiddenVisibility:    return 1;
 377   case GlobalValue::ProtectedVisibility: return 2;
 378   }
 379   llvm_unreachable("Invalid visibility");
 380 }
 381
 382 static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
 383   switch (GV->getThreadLocalMode()) {
 384     case GlobalVariable::NotThreadLocal:         return 0;
 385     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 386     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 387     case GlobalVariable::InitialExecTLSModel:    return 3;
 388     case GlobalVariable::LocalExecTLSModel:      return 4;
 389   }
 390   llvm_unreachable("Invalid TLS model");
 391 }
 392
 393 // Emit top-level description of module, including target triple, inline asm,
 394 // descriptors for global variables, and function prototype info.
 395 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 396                             BitstreamWriter &Stream) {
 397   // Emit the list of dependent libraries for the Module.
 398   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 399     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 400
 401   // Emit various pieces of data attached to a module.
 402   if (!M->getTargetTriple().empty())
 403     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 404                       0/*TODO*/, Stream);
 405   if (!M->getDataLayout().empty())
 406     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 407                       0/*TODO*/, Stream);
 408   if (!M->getModuleInlineAsm().empty())
 409     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 410                       0/*TODO*/, Stream);
 411
 412   // Emit information about sections and GC, computing how many there are. Also
 413   // compute the maximum alignment value.
 414   std::map<std::string, unsigned> SectionMap;
 415   std::map<std::string, unsigned> GCMap;
 416   unsigned MaxAlignment = 0;
 417   unsigned MaxGlobalType = 0;
 418   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 419        GV != E; ++GV) {
 420     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 421     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 422     if (GV->hasSection()) {
 423       // Give section names unique ID's.
 424       unsigned &Entry = SectionMap[GV->getSection()];
 425       if (!Entry) {
 426         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 427                           0/*TODO*/, Stream);
 428         Entry = SectionMap.size();
 429       }
 430     }
 431   }
 432   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 433     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 434     if (F->hasSection()) {
 435       // Give section names unique ID's.
 436       unsigned &Entry = SectionMap[F->getSection()];
 437       if (!Entry) {
 438         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 439                           0/*TODO*/, Stream);
 440         Entry = SectionMap.size();
 441       }
 442     }
 443     if (F->hasGC()) {
 444       // Same for GC names.
 445       unsigned &Entry = GCMap[F->getGC()];
 446       if (!Entry) {
 447         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 448                           0/*TODO*/, Stream);
 449         Entry = GCMap.size();
 450       }
 451     }
 452   }
 453
 454   // Emit abbrev for globals, now that we know # sections and max alignment.
 455   unsigned SimpleGVarAbbrev = 0;
 456   if (!M->global_empty()) {
 457     // Add an abbrev for common globals with no visibility or thread localness.
 458     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 459     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 461                               Log2_32_Ceil(MaxGlobalType+1)));
 462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 465     if (MaxAlignment == 0)                                      // Alignment.
 466       Abbv->Add(BitCodeAbbrevOp(0));
 467     else {
 468       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 469       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 470                                Log2_32_Ceil(MaxEncAlignment+1)));
 471     }
 472     if (SectionMap.empty())                                    // Section.
 473       Abbv->Add(BitCodeAbbrevOp(0));
 474     else
 475       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 476                                Log2_32_Ceil(SectionMap.size()+1)));
 477     // Don't bother emitting vis + thread local.
 478     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 479   }
 480
 481   // Emit the global variable information.
 482   SmallVector<unsigned, 64> Vals;
 483   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 484        GV != E; ++GV) {
 485     unsigned AbbrevToUse = 0;
 486
 487     // GLOBALVAR: [type, isconst, initid,
 488     //             linkage, alignment, section, visibility, threadlocal,
 489     //             unnamed_addr]
 490     Vals.push_back(VE.getTypeID(GV->getType()));
 491     Vals.push_back(GV->isConstant());
 492     Vals.push_back(GV->isDeclaration() ? 0 :
 493                    (VE.getValueID(GV->getInitializer()) + 1));
 494     Vals.push_back(getEncodedLinkage(GV));
 495     Vals.push_back(Log2_32(GV->getAlignment())+1);
 496     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 497     if (GV->isThreadLocal() ||
 498         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 499         GV->hasUnnamedAddr()) {
 500       Vals.push_back(getEncodedVisibility(GV));
 501       Vals.push_back(getEncodedThreadLocalMode(GV));
 502       Vals.push_back(GV->hasUnnamedAddr());
 503     } else {
 504       AbbrevToUse = SimpleGVarAbbrev;
 505     }
 506
 507     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 508     Vals.clear();
 509   }
 510
 511   // Emit the function proto information.
 512   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 513     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 514     //             section, visibility, gc, unnamed_addr]
 515     Vals.push_back(VE.getTypeID(F->getType()));
 516     Vals.push_back(F->getCallingConv());
 517     Vals.push_back(F->isDeclaration());
 518     Vals.push_back(getEncodedLinkage(F));
 519     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 520     Vals.push_back(Log2_32(F->getAlignment())+1);
 521     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 522     Vals.push_back(getEncodedVisibility(F));
 523     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 524     Vals.push_back(F->hasUnnamedAddr());
 525
 526     unsigned AbbrevToUse = 0;
 527     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 528     Vals.clear();
 529   }
 530
 531   // Emit the alias information.
 532   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 533        AI != E; ++AI) {
 534     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 535     Vals.push_back(VE.getTypeID(AI->getType()));
 536     Vals.push_back(VE.getValueID(AI->getAliasee()));
 537     Vals.push_back(getEncodedLinkage(AI));
 538     Vals.push_back(getEncodedVisibility(AI));
 539     unsigned AbbrevToUse = 0;
 540     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 541     Vals.clear();
 542   }
 543 }
 544
 545 static uint64_t GetOptimizationFlags(const Value *V) {
 546   uint64_t Flags = 0;
 547
 548   if (const OverflowingBinaryOperator *OBO =
 549         dyn_cast<OverflowingBinaryOperator>(V)) {
 550     if (OBO->hasNoSignedWrap())
 551       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 552     if (OBO->hasNoUnsignedWrap())
 553       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 554   } else if (const PossiblyExactOperator *PEO =
 555                dyn_cast<PossiblyExactOperator>(V)) {
 556     if (PEO->isExact())
 557       Flags |= 1 << bitc::PEO_EXACT;
 558   }
 559
 560   return Flags;
 561 }
 562
 563 static void WriteMDNode(const MDNode *N,
 564                         const ValueEnumerator &VE,
 565                         BitstreamWriter &Stream,
 566                         SmallVector<uint64_t, 64> &Record) {
 567   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 568     if (N->getOperand(i)) {
 569       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 570       Record.push_back(VE.getValueID(N->getOperand(i)));
 571     } else {
 572       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 573       Record.push_back(0);
 574     }
 575   }
 576   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 577                                            bitc::METADATA_NODE;
 578   Stream.EmitRecord(MDCode, Record, 0);
 579   Record.clear();
 580 }
 581
 582 static void WriteModuleMetadata(const Module *M,
 583                                 const ValueEnumerator &VE,
 584                                 BitstreamWriter &Stream) {
 585   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 586   bool StartedMetadataBlock = false;
 587   unsigned MDSAbbrev = 0;
 588   SmallVector<uint64_t, 64> Record;
 589   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 590
 591     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 592       if (!N->isFunctionLocal() || !N->getFunction()) {
 593         if (!StartedMetadataBlock) {
 594           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 595           StartedMetadataBlock = true;
 596         }
 597         WriteMDNode(N, VE, Stream, Record);
 598       }
 599     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 600       if (!StartedMetadataBlock)  {
 601         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 602
 603         // Abbrev for METADATA_STRING.
 604         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 605         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 606         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 607         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 608         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 609         StartedMetadataBlock = true;
 610       }
 611
 612       // Code: [strchar x N]
 613       Record.append(MDS->begin(), MDS->end());
 614
 615       // Emit the finished record.
 616       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 617       Record.clear();
 618     }
 619   }
 620
 621   // Write named metadata.
 622   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 623        E = M->named_metadata_end(); I != E; ++I) {
 624     const NamedMDNode *NMD = I;
 625     if (!StartedMetadataBlock)  {
 626       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 627       StartedMetadataBlock = true;
 628     }
 629
 630     // Write name.
 631     StringRef Str = NMD->getName();
 632     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 633       Record.push_back(Str[i]);
 634     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 635     Record.clear();
 636
 637     // Write named metadata operands.
 638     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 639       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 640     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 641     Record.clear();
 642   }
 643
 644   if (StartedMetadataBlock)
 645     Stream.ExitBlock();
 646 }
 647
 648 static void WriteFunctionLocalMetadata(const Function &F,
 649                                        const ValueEnumerator &VE,
 650                                        BitstreamWriter &Stream) {
 651   bool StartedMetadataBlock = false;
 652   SmallVector<uint64_t, 64> Record;
 653   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
 654   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 655     if (const MDNode *N = Vals[i])
 656       if (N->isFunctionLocal() && N->getFunction() == &F) {
 657         if (!StartedMetadataBlock) {
 658           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 659           StartedMetadataBlock = true;
 660         }
 661         WriteMDNode(N, VE, Stream, Record);
 662       }
 663
 664   if (StartedMetadataBlock)
 665     Stream.ExitBlock();
 666 }
 667
 668 static void WriteMetadataAttachment(const Function &F,
 669                                     const ValueEnumerator &VE,
 670                                     BitstreamWriter &Stream) {
 671   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 672
 673   SmallVector<uint64_t, 64> Record;
 674
 675   // Write metadata attachments
 676   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 677   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 678
 679   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 680     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 681          I != E; ++I) {
 682       MDs.clear();
 683       I->getAllMetadataOtherThanDebugLoc(MDs);
 684
 685       // If no metadata, ignore instruction.
 686       if (MDs.empty()) continue;
 687
 688       Record.push_back(VE.getInstructionID(I));
 689
 690       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 691         Record.push_back(MDs[i].first);
 692         Record.push_back(VE.getValueID(MDs[i].second));
 693       }
 694       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 695       Record.clear();
 696     }
 697
 698   Stream.ExitBlock();
 699 }
 700
 701 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 702   SmallVector<uint64_t, 64> Record;
 703
 704   // Write metadata kinds
 705   // METADATA_KIND - [n x [id, name]]
 706   SmallVector<StringRef, 4> Names;
 707   M->getMDKindNames(Names);
 708
 709   if (Names.empty()) return;
 710
 711   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 712
 713   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 714     Record.push_back(MDKindID);
 715     StringRef KName = Names[MDKindID];
 716     Record.append(KName.begin(), KName.end());
 717
 718     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 719     Record.clear();
 720   }
 721
 722   Stream.ExitBlock();
 723 }
 724
 725 static void EmitAPInt(SmallVectorImpl<uint64_t> &Vals,
 726                       unsigned &Code, unsigned &AbbrevToUse, const APInt &Val,
 727                       bool EmitSizeForWideNumbers = false
 728                       ) {
 729   if (Val.getBitWidth() <= 64) {
 730     uint64_t V = Val.getSExtValue();
 731     if ((int64_t)V >= 0)
 732       Vals.push_back(V << 1);
 733     else
 734       Vals.push_back((-V << 1) | 1);
 735     Code = bitc::CST_CODE_INTEGER;
 736     AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 737   } else {
 738     // Wide integers, > 64 bits in size.
 739     // We have an arbitrary precision integer value to write whose
 740     // bit width is > 64. However, in canonical unsigned integer
 741     // format it is likely that the high bits are going to be zero.
 742     // So, we only write the number of active words.
 743     unsigned NWords = Val.getActiveWords();
 744
 745     if (EmitSizeForWideNumbers)
 746       Vals.push_back(NWords);
 747
 748     const uint64_t *RawWords = Val.getRawData();
 749     for (unsigned i = 0; i != NWords; ++i) {
 750       int64_t V = RawWords[i];
 751       if (V >= 0)
 752         Vals.push_back(V << 1);
 753       else
 754         Vals.push_back((-V << 1) | 1);
 755     }
 756     Code = bitc::CST_CODE_WIDE_INTEGER;
 757   }
 758 }
 759
 760 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 761                            const ValueEnumerator &VE,
 762                            BitstreamWriter &Stream, bool isGlobal) {
 763   if (FirstVal == LastVal) return;
 764
 765   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 766
 767   unsigned AggregateAbbrev = 0;
 768   unsigned String8Abbrev = 0;
 769   unsigned CString7Abbrev = 0;
 770   unsigned CString6Abbrev = 0;
 771   // If this is a constant pool for the module, emit module-specific abbrevs.
 772   if (isGlobal) {
 773     // Abbrev for CST_CODE_AGGREGATE.
 774     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 775     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 776     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 777     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 778     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 779
 780     // Abbrev for CST_CODE_STRING.
 781     Abbv = new BitCodeAbbrev();
 782     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 785     String8Abbrev = Stream.EmitAbbrev(Abbv);
 786     // Abbrev for CST_CODE_CSTRING.
 787     Abbv = new BitCodeAbbrev();
 788     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 790     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 791     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 792     // Abbrev for CST_CODE_CSTRING.
 793     Abbv = new BitCodeAbbrev();
 794     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 797     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 798   }
 799
 800   SmallVector<uint64_t, 64> Record;
 801
 802   const ValueEnumerator::ValueList &Vals = VE.getValues();
 803   Type *LastTy = 0;
 804   for (unsigned i = FirstVal; i != LastVal; ++i) {
 805     const Value *V = Vals[i].first;
 806     // If we need to switch types, do so now.
 807     if (V->getType() != LastTy) {
 808       LastTy = V->getType();
 809       Record.push_back(VE.getTypeID(LastTy));
 810       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 811                         CONSTANTS_SETTYPE_ABBREV);
 812       Record.clear();
 813     }
 814
 815     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 816       Record.push_back(unsigned(IA->hasSideEffects()) |
 817                        unsigned(IA->isAlignStack()) << 1 |
 818                        unsigned(IA->getDialect()&1) << 2);
 819
 820       // Add the asm string.
 821       const std::string &AsmStr = IA->getAsmString();
 822       Record.push_back(AsmStr.size());
 823       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 824         Record.push_back(AsmStr[i]);
 825
 826       // Add the constraint string.
 827       const std::string &ConstraintStr = IA->getConstraintString();
 828       Record.push_back(ConstraintStr.size());
 829       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 830         Record.push_back(ConstraintStr[i]);
 831       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 832       Record.clear();
 833       continue;
 834     }
 835     const Constant *C = cast<Constant>(V);
 836     unsigned Code = -1U;
 837     unsigned AbbrevToUse = 0;
 838     if (C->isNullValue()) {
 839       Code = bitc::CST_CODE_NULL;
 840     } else if (isa<UndefValue>(C)) {
 841       Code = bitc::CST_CODE_UNDEF;
 842     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 843       EmitAPInt(Record, Code, AbbrevToUse, IV->getValue());
 844     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 845       Code = bitc::CST_CODE_FLOAT;
 846       Type *Ty = CFP->getType();
 847       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
 848         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 849       } else if (Ty->isX86_FP80Ty()) {
 850         // api needed to prevent premature destruction
 851         // bits are not in the same order as a normal i80 APInt, compensate.
 852         APInt api = CFP->getValueAPF().bitcastToAPInt();
 853         const uint64_t *p = api.getRawData();
 854         Record.push_back((p[1] << 48) | (p[0] >> 16));
 855         Record.push_back(p[0] & 0xffffLL);
 856       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 857         APInt api = CFP->getValueAPF().bitcastToAPInt();
 858         const uint64_t *p = api.getRawData();
 859         Record.push_back(p[0]);
 860         Record.push_back(p[1]);
 861       } else {
 862         assert (0 && "Unknown FP type!");
 863       }
 864     } else if (isa<ConstantDataSequential>(C) &&
 865                cast<ConstantDataSequential>(C)->isString()) {
 866       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
 867       // Emit constant strings specially.
 868       unsigned NumElts = Str->getNumElements();
 869       // If this is a null-terminated string, use the denser CSTRING encoding.
 870       if (Str->isCString()) {
 871         Code = bitc::CST_CODE_CSTRING;
 872         --NumElts;  // Don't encode the null, which isn't allowed by char6.
 873       } else {
 874         Code = bitc::CST_CODE_STRING;
 875         AbbrevToUse = String8Abbrev;
 876       }
 877       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 878       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 879       for (unsigned i = 0; i != NumElts; ++i) {
 880         unsigned char V = Str->getElementAsInteger(i);
 881         Record.push_back(V);
 882         isCStr7 &= (V & 128) == 0;
 883         if (isCStrChar6)
 884           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 885       }
 886
 887       if (isCStrChar6)
 888         AbbrevToUse = CString6Abbrev;
 889       else if (isCStr7)
 890         AbbrevToUse = CString7Abbrev;
 891     } else if (const ConstantDataSequential *CDS =
 892                   dyn_cast<ConstantDataSequential>(C)) {
 893       Code = bitc::CST_CODE_DATA;
 894       Type *EltTy = CDS->getType()->getElementType();
 895       if (isa<IntegerType>(EltTy)) {
 896         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
 897           Record.push_back(CDS->getElementAsInteger(i));
 898       } else if (EltTy->isFloatTy()) {
 899         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
 900           union { float F; uint32_t I; };
 901           F = CDS->getElementAsFloat(i);
 902           Record.push_back(I);
 903         }
 904       } else {
 905         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
 906         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
 907           union { double F; uint64_t I; };
 908           F = CDS->getElementAsDouble(i);
 909           Record.push_back(I);
 910         }
 911       }
 912     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
 913                isa<ConstantVector>(C)) {
 914       Code = bitc::CST_CODE_AGGREGATE;
 915       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 916         Record.push_back(VE.getValueID(C->getOperand(i)));
 917       AbbrevToUse = AggregateAbbrev;
 918     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 919       switch (CE->getOpcode()) {
 920       default:
 921         if (Instruction::isCast(CE->getOpcode())) {
 922           Code = bitc::CST_CODE_CE_CAST;
 923           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 924           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 925           Record.push_back(VE.getValueID(C->getOperand(0)));
 926           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 927         } else {
 928           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 929           Code = bitc::CST_CODE_CE_BINOP;
 930           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 931           Record.push_back(VE.getValueID(C->getOperand(0)));
 932           Record.push_back(VE.getValueID(C->getOperand(1)));
 933           uint64_t Flags = GetOptimizationFlags(CE);
 934           if (Flags != 0)
 935             Record.push_back(Flags);
 936         }
 937         break;
 938       case Instruction::GetElementPtr:
 939         Code = bitc::CST_CODE_CE_GEP;
 940         if (cast<GEPOperator>(C)->isInBounds())
 941           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 942         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 943           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 944           Record.push_back(VE.getValueID(C->getOperand(i)));
 945         }
 946         break;
 947       case Instruction::Select:
 948         Code = bitc::CST_CODE_CE_SELECT;
 949         Record.push_back(VE.getValueID(C->getOperand(0)));
 950         Record.push_back(VE.getValueID(C->getOperand(1)));
 951         Record.push_back(VE.getValueID(C->getOperand(2)));
 952         break;
 953       case Instruction::ExtractElement:
 954         Code = bitc::CST_CODE_CE_EXTRACTELT;
 955         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 956         Record.push_back(VE.getValueID(C->getOperand(0)));
 957         Record.push_back(VE.getValueID(C->getOperand(1)));
 958         break;
 959       case Instruction::InsertElement:
 960         Code = bitc::CST_CODE_CE_INSERTELT;
 961         Record.push_back(VE.getValueID(C->getOperand(0)));
 962         Record.push_back(VE.getValueID(C->getOperand(1)));
 963         Record.push_back(VE.getValueID(C->getOperand(2)));
 964         break;
 965       case Instruction::ShuffleVector:
 966         // If the return type and argument types are the same, this is a
 967         // standard shufflevector instruction.  If the types are different,
 968         // then the shuffle is widening or truncating the input vectors, and
 969         // the argument type must also be encoded.
 970         if (C->getType() == C->getOperand(0)->getType()) {
 971           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 972         } else {
 973           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 974           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 975         }
 976         Record.push_back(VE.getValueID(C->getOperand(0)));
 977         Record.push_back(VE.getValueID(C->getOperand(1)));
 978         Record.push_back(VE.getValueID(C->getOperand(2)));
 979         break;
 980       case Instruction::ICmp:
 981       case Instruction::FCmp:
 982         Code = bitc::CST_CODE_CE_CMP;
 983         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 984         Record.push_back(VE.getValueID(C->getOperand(0)));
 985         Record.push_back(VE.getValueID(C->getOperand(1)));
 986         Record.push_back(CE->getPredicate());
 987         break;
 988       }
 989     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 990       Code = bitc::CST_CODE_BLOCKADDRESS;
 991       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 992       Record.push_back(VE.getValueID(BA->getFunction()));
 993       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 994     } else {
 995 #ifndef NDEBUG
 996       C->dump();
 997 #endif
 998       llvm_unreachable("Unknown constant!");
 999     }
1000     Stream.EmitRecord(Code, Record, AbbrevToUse);
1001     Record.clear();
1002   }
1003
1004   Stream.ExitBlock();
1005 }
1006
1007 static void WriteModuleConstants(const ValueEnumerator &VE,
1008                                  BitstreamWriter &Stream) {
1009   const ValueEnumerator::ValueList &Vals = VE.getValues();
1010
1011   // Find the first constant to emit, which is the first non-globalvalue value.
1012   // We know globalvalues have been emitted by WriteModuleInfo.
1013   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1014     if (!isa<GlobalValue>(Vals[i].first)) {
1015       WriteConstants(i, Vals.size(), VE, Stream, true);
1016       return;
1017     }
1018   }
1019 }
1020
1021 /// PushValueAndType - The file has to encode both the value and type id for
1022 /// many values, because we need to know what type to create for forward
1023 /// references.  However, most operands are not forward references, so this type
1024 /// field is not needed.
1025 ///
1026 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1027 /// instruction ID, then it is a forward reference, and it also includes the
1028 /// type ID.
1029 static bool PushValueAndType(const Value *V, unsigned InstID,
1030                              SmallVector<unsigned, 64> &Vals,
1031                              ValueEnumerator &VE) {
1032   unsigned ValID = VE.getValueID(V);
1033   Vals.push_back(ValID);
1034   if (ValID >= InstID) {
1035     Vals.push_back(VE.getTypeID(V->getType()));
1036     return true;
1037   }
1038   return false;
1039 }
1040
1041 /// WriteInstruction - Emit an instruction to the specified stream.
1042 static void WriteInstruction(const Instruction &I, unsigned InstID,
1043                              ValueEnumerator &VE, BitstreamWriter &Stream,
1044                              SmallVector<unsigned, 64> &Vals) {
1045   unsigned Code = 0;
1046   unsigned AbbrevToUse = 0;
1047   VE.setInstructionID(&I);
1048   switch (I.getOpcode()) {
1049   default:
1050     if (Instruction::isCast(I.getOpcode())) {
1051       Code = bitc::FUNC_CODE_INST_CAST;
1052       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1053         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1054       Vals.push_back(VE.getTypeID(I.getType()));
1055       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1056     } else {
1057       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1058       Code = bitc::FUNC_CODE_INST_BINOP;
1059       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1060         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1061       Vals.push_back(VE.getValueID(I.getOperand(1)));
1062       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1063       uint64_t Flags = GetOptimizationFlags(&I);
1064       if (Flags != 0) {
1065         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1066           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1067         Vals.push_back(Flags);
1068       }
1069     }
1070     break;
1071
1072   case Instruction::GetElementPtr:
1073     Code = bitc::FUNC_CODE_INST_GEP;
1074     if (cast<GEPOperator>(&I)->isInBounds())
1075       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1076     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1077       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1078     break;
1079   case Instruction::ExtractValue: {
1080     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1081     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1082     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1083     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1084       Vals.push_back(*i);
1085     break;
1086   }
1087   case Instruction::InsertValue: {
1088     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1089     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1090     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1091     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1092     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1093       Vals.push_back(*i);
1094     break;
1095   }
1096   case Instruction::Select:
1097     Code = bitc::FUNC_CODE_INST_VSELECT;
1098     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1099     Vals.push_back(VE.getValueID(I.getOperand(2)));
1100     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1101     break;
1102   case Instruction::ExtractElement:
1103     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1104     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1105     Vals.push_back(VE.getValueID(I.getOperand(1)));
1106     break;
1107   case Instruction::InsertElement:
1108     Code = bitc::FUNC_CODE_INST_INSERTELT;
1109     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1110     Vals.push_back(VE.getValueID(I.getOperand(1)));
1111     Vals.push_back(VE.getValueID(I.getOperand(2)));
1112     break;
1113   case Instruction::ShuffleVector:
1114     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1115     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1116     Vals.push_back(VE.getValueID(I.getOperand(1)));
1117     Vals.push_back(VE.getValueID(I.getOperand(2)));
1118     break;
1119   case Instruction::ICmp:
1120   case Instruction::FCmp:
1121     // compare returning Int1Ty or vector of Int1Ty
1122     Code = bitc::FUNC_CODE_INST_CMP2;
1123     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1124     Vals.push_back(VE.getValueID(I.getOperand(1)));
1125     Vals.push_back(cast<CmpInst>(I).getPredicate());
1126     break;
1127
1128   case Instruction::Ret:
1129     {
1130       Code = bitc::FUNC_CODE_INST_RET;
1131       unsigned NumOperands = I.getNumOperands();
1132       if (NumOperands == 0)
1133         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1134       else if (NumOperands == 1) {
1135         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1136           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1137       } else {
1138         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1139           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1140       }
1141     }
1142     break;
1143   case Instruction::Br:
1144     {
1145       Code = bitc::FUNC_CODE_INST_BR;
1146       BranchInst &II = cast<BranchInst>(I);
1147       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1148       if (II.isConditional()) {
1149         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1150         Vals.push_back(VE.getValueID(II.getCondition()));
1151       }
1152     }
1153     break;
1154   case Instruction::Switch:
1155     {
1156       // Redefine Vals, since here we need to use 64 bit values
1157       // explicitly to store large APInt numbers.
1158       SmallVector<uint64_t, 128> Vals64;
1159
1160       Code = bitc::FUNC_CODE_INST_SWITCH;
1161       SwitchInst &SI = cast<SwitchInst>(I);
1162
1163       uint32_t SwitchRecordHeader = SI.hash() | (SWITCH_INST_MAGIC << 16);
1164       Vals64.push_back(SwitchRecordHeader);
1165
1166       Vals64.push_back(VE.getTypeID(SI.getCondition()->getType()));
1167       Vals64.push_back(VE.getValueID(SI.getCondition()));
1168       Vals64.push_back(VE.getValueID(SI.getDefaultDest()));
1169       Vals64.push_back(SI.getNumCases());
1170       for (SwitchInst::CaseIt i = SI.case_begin(), e = SI.case_end();
1171            i != e; ++i) {
1172         IntegersSubset& CaseRanges = i.getCaseValueEx();
1173         unsigned Code, Abbrev; // will unused.
1174
1175         if (CaseRanges.isSingleNumber()) {
1176           Vals64.push_back(1/*NumItems = 1*/);
1177           Vals64.push_back(true/*IsSingleNumber = true*/);
1178           EmitAPInt(Vals64, Code, Abbrev, CaseRanges.getSingleNumber(0), true);
1179         } else {
1180
1181           Vals64.push_back(CaseRanges.getNumItems());
1182
1183           if (CaseRanges.isSingleNumbersOnly()) {
1184             for (unsigned ri = 0, rn = CaseRanges.getNumItems();
1185                  ri != rn; ++ri) {
1186
1187               Vals64.push_back(true/*IsSingleNumber = true*/);
1188
1189               EmitAPInt(Vals64, Code, Abbrev,
1190                         CaseRanges.getSingleNumber(ri), true);
1191             }
1192           } else
1193             for (unsigned ri = 0, rn = CaseRanges.getNumItems();
1194                  ri != rn; ++ri) {
1195               IntegersSubset::Range r = CaseRanges.getItem(ri);
1196               bool IsSingleNumber = CaseRanges.isSingleNumber(ri);
1197
1198               Vals64.push_back(IsSingleNumber);
1199
1200               EmitAPInt(Vals64, Code, Abbrev, r.getLow(), true);
1201               if (!IsSingleNumber)
1202                 EmitAPInt(Vals64, Code, Abbrev, r.getHigh(), true);
1203             }
1204         }
1205         Vals64.push_back(VE.getValueID(i.getCaseSuccessor()));
1206       }
1207
1208       Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1209
1210       // Also do expected action - clear external Vals collection:
1211       Vals.clear();
1212       return;
1213     }
1214     break;
1215   case Instruction::IndirectBr:
1216     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1217     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1218     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1219       Vals.push_back(VE.getValueID(I.getOperand(i)));
1220     break;
1221
1222   case Instruction::Invoke: {
1223     const InvokeInst *II = cast<InvokeInst>(&I);
1224     const Value *Callee(II->getCalledValue());
1225     PointerType *PTy = cast<PointerType>(Callee->getType());
1226     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1227     Code = bitc::FUNC_CODE_INST_INVOKE;
1228
1229     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1230     Vals.push_back(II->getCallingConv());
1231     Vals.push_back(VE.getValueID(II->getNormalDest()));
1232     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1233     PushValueAndType(Callee, InstID, Vals, VE);
1234
1235     // Emit value #'s for the fixed parameters.
1236     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1237       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1238
1239     // Emit type/value pairs for varargs params.
1240     if (FTy->isVarArg()) {
1241       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1242            i != e; ++i)
1243         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1244     }
1245     break;
1246   }
1247   case Instruction::Resume:
1248     Code = bitc::FUNC_CODE_INST_RESUME;
1249     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1250     break;
1251   case Instruction::Unreachable:
1252     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1253     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1254     break;
1255
1256   case Instruction::PHI: {
1257     const PHINode &PN = cast<PHINode>(I);
1258     Code = bitc::FUNC_CODE_INST_PHI;
1259     Vals.push_back(VE.getTypeID(PN.getType()));
1260     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1261       Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1262       Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1263     }
1264     break;
1265   }
1266
1267   case Instruction::LandingPad: {
1268     const LandingPadInst &LP = cast<LandingPadInst>(I);
1269     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1270     Vals.push_back(VE.getTypeID(LP.getType()));
1271     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1272     Vals.push_back(LP.isCleanup());
1273     Vals.push_back(LP.getNumClauses());
1274     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1275       if (LP.isCatch(I))
1276         Vals.push_back(LandingPadInst::Catch);
1277       else
1278         Vals.push_back(LandingPadInst::Filter);
1279       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1280     }
1281     break;
1282   }
1283
1284   case Instruction::Alloca:
1285     Code = bitc::FUNC_CODE_INST_ALLOCA;
1286     Vals.push_back(VE.getTypeID(I.getType()));
1287     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1288     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1289     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1290     break;
1291
1292   case Instruction::Load:
1293     if (cast<LoadInst>(I).isAtomic()) {
1294       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1295       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1296     } else {
1297       Code = bitc::FUNC_CODE_INST_LOAD;
1298       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1299         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1300     }
1301     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1302     Vals.push_back(cast<LoadInst>(I).isVolatile());
1303     if (cast<LoadInst>(I).isAtomic()) {
1304       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1305       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1306     }
1307     break;
1308   case Instruction::Store:
1309     if (cast<StoreInst>(I).isAtomic())
1310       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1311     else
1312       Code = bitc::FUNC_CODE_INST_STORE;
1313     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1314     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1315     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1316     Vals.push_back(cast<StoreInst>(I).isVolatile());
1317     if (cast<StoreInst>(I).isAtomic()) {
1318       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1319       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1320     }
1321     break;
1322   case Instruction::AtomicCmpXchg:
1323     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1324     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1325     Vals.push_back(VE.getValueID(I.getOperand(1)));       // cmp.
1326     Vals.push_back(VE.getValueID(I.getOperand(2)));       // newval.
1327     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1328     Vals.push_back(GetEncodedOrdering(
1329                      cast<AtomicCmpXchgInst>(I).getOrdering()));
1330     Vals.push_back(GetEncodedSynchScope(
1331                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1332     break;
1333   case Instruction::AtomicRMW:
1334     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1335     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1336     Vals.push_back(VE.getValueID(I.getOperand(1)));       // val.
1337     Vals.push_back(GetEncodedRMWOperation(
1338                      cast<AtomicRMWInst>(I).getOperation()));
1339     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1340     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1341     Vals.push_back(GetEncodedSynchScope(
1342                      cast<AtomicRMWInst>(I).getSynchScope()));
1343     break;
1344   case Instruction::Fence:
1345     Code = bitc::FUNC_CODE_INST_FENCE;
1346     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1347     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1348     break;
1349   case Instruction::Call: {
1350     const CallInst &CI = cast<CallInst>(I);
1351     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1352     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1353
1354     Code = bitc::FUNC_CODE_INST_CALL;
1355
1356     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1357     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1358     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1359
1360     // Emit value #'s for the fixed parameters.
1361     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1362       Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1363
1364     // Emit type/value pairs for varargs params.
1365     if (FTy->isVarArg()) {
1366       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1367            i != e; ++i)
1368         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1369     }
1370     break;
1371   }
1372   case Instruction::VAArg:
1373     Code = bitc::FUNC_CODE_INST_VAARG;
1374     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1375     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1376     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1377     break;
1378   }
1379
1380   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1381   Vals.clear();
1382 }
1383
1384 // Emit names for globals/functions etc.
1385 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1386                                   const ValueEnumerator &VE,
1387                                   BitstreamWriter &Stream) {
1388   if (VST.empty()) return;
1389   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1390
1391   // FIXME: Set up the abbrev, we know how many values there are!
1392   // FIXME: We know if the type names can use 7-bit ascii.
1393   SmallVector<unsigned, 64> NameVals;
1394
1395   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1396        SI != SE; ++SI) {
1397
1398     const ValueName &Name = *SI;
1399
1400     // Figure out the encoding to use for the name.
1401     bool is7Bit = true;
1402     bool isChar6 = true;
1403     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1404          C != E; ++C) {
1405       if (isChar6)
1406         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1407       if ((unsigned char)*C & 128) {
1408         is7Bit = false;
1409         break;  // don't bother scanning the rest.
1410       }
1411     }
1412
1413     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1414
1415     // VST_ENTRY:   [valueid, namechar x N]
1416     // VST_BBENTRY: [bbid, namechar x N]
1417     unsigned Code;
1418     if (isa<BasicBlock>(SI->getValue())) {
1419       Code = bitc::VST_CODE_BBENTRY;
1420       if (isChar6)
1421         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1422     } else {
1423       Code = bitc::VST_CODE_ENTRY;
1424       if (isChar6)
1425         AbbrevToUse = VST_ENTRY_6_ABBREV;
1426       else if (is7Bit)
1427         AbbrevToUse = VST_ENTRY_7_ABBREV;
1428     }
1429
1430     NameVals.push_back(VE.getValueID(SI->getValue()));
1431     for (const char *P = Name.getKeyData(),
1432          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1433       NameVals.push_back((unsigned char)*P);
1434
1435     // Emit the finished record.
1436     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1437     NameVals.clear();
1438   }
1439   Stream.ExitBlock();
1440 }
1441
1442 /// WriteFunction - Emit a function body to the module stream.
1443 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1444                           BitstreamWriter &Stream) {
1445   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1446   VE.incorporateFunction(F);
1447
1448   SmallVector<unsigned, 64> Vals;
1449
1450   // Emit the number of basic blocks, so the reader can create them ahead of
1451   // time.
1452   Vals.push_back(VE.getBasicBlocks().size());
1453   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1454   Vals.clear();
1455
1456   // If there are function-local constants, emit them now.
1457   unsigned CstStart, CstEnd;
1458   VE.getFunctionConstantRange(CstStart, CstEnd);
1459   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1460
1461   // If there is function-local metadata, emit it now.
1462   WriteFunctionLocalMetadata(F, VE, Stream);
1463
1464   // Keep a running idea of what the instruction ID is.
1465   unsigned InstID = CstEnd;
1466
1467   bool NeedsMetadataAttachment = false;
1468
1469   DebugLoc LastDL;
1470
1471   // Finally, emit all the instructions, in order.
1472   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1473     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1474          I != E; ++I) {
1475       WriteInstruction(*I, InstID, VE, Stream, Vals);
1476
1477       if (!I->getType()->isVoidTy())
1478         ++InstID;
1479
1480       // If the instruction has metadata, write a metadata attachment later.
1481       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1482
1483       // If the instruction has a debug location, emit it.
1484       DebugLoc DL = I->getDebugLoc();
1485       if (DL.isUnknown()) {
1486         // nothing todo.
1487       } else if (DL == LastDL) {
1488         // Just repeat the same debug loc as last time.
1489         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1490       } else {
1491         MDNode *Scope, *IA;
1492         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1493
1494         Vals.push_back(DL.getLine());
1495         Vals.push_back(DL.getCol());
1496         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1497         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1498         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1499         Vals.clear();
1500
1501         LastDL = DL;
1502       }
1503     }
1504
1505   // Emit names for all the instructions etc.
1506   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1507
1508   if (NeedsMetadataAttachment)
1509     WriteMetadataAttachment(F, VE, Stream);
1510   VE.purgeFunction();
1511   Stream.ExitBlock();
1512 }
1513
1514 // Emit blockinfo, which defines the standard abbreviations etc.
1515 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1516   // We only want to emit block info records for blocks that have multiple
1517   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1518   // blocks can defined their abbrevs inline.
1519   Stream.EnterBlockInfoBlock(2);
1520
1521   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1522     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1527     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1528                                    Abbv) != VST_ENTRY_8_ABBREV)
1529       llvm_unreachable("Unexpected abbrev ordering!");
1530   }
1531
1532   { // 7-bit fixed width VST_ENTRY strings.
1533     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1534     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1538     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1539                                    Abbv) != VST_ENTRY_7_ABBREV)
1540       llvm_unreachable("Unexpected abbrev ordering!");
1541   }
1542   { // 6-bit char6 VST_ENTRY strings.
1543     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1544     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1548     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1549                                    Abbv) != VST_ENTRY_6_ABBREV)
1550       llvm_unreachable("Unexpected abbrev ordering!");
1551   }
1552   { // 6-bit char6 VST_BBENTRY strings.
1553     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1554     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1555     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1556     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1557     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1558     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1559                                    Abbv) != VST_BBENTRY_6_ABBREV)
1560       llvm_unreachable("Unexpected abbrev ordering!");
1561   }
1562
1563
1564
1565   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1566     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1567     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1569                               Log2_32_Ceil(VE.getTypes().size()+1)));
1570     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1571                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1572       llvm_unreachable("Unexpected abbrev ordering!");
1573   }
1574
1575   { // INTEGER abbrev for CONSTANTS_BLOCK.
1576     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1577     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1579     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1580                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1581       llvm_unreachable("Unexpected abbrev ordering!");
1582   }
1583
1584   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1585     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1586     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1587     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1589                               Log2_32_Ceil(VE.getTypes().size()+1)));
1590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1591
1592     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1593                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1594       llvm_unreachable("Unexpected abbrev ordering!");
1595   }
1596   { // NULL abbrev for CONSTANTS_BLOCK.
1597     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1598     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1599     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1600                                    Abbv) != CONSTANTS_NULL_Abbrev)
1601       llvm_unreachable("Unexpected abbrev ordering!");
1602   }
1603
1604   // FIXME: This should only use space for first class types!
1605
1606   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1607     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1608     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1609     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1610     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1612     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1613                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1614       llvm_unreachable("Unexpected abbrev ordering!");
1615   }
1616   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1617     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1618     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1619     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1620     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1621     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1622     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1623                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1624       llvm_unreachable("Unexpected abbrev ordering!");
1625   }
1626   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1627     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1628     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1629     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1630     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1633     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1634                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1635       llvm_unreachable("Unexpected abbrev ordering!");
1636   }
1637   { // INST_CAST abbrev for FUNCTION_BLOCK.
1638     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1639     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1640     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1642                               Log2_32_Ceil(VE.getTypes().size()+1)));
1643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1644     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1645                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1646       llvm_unreachable("Unexpected abbrev ordering!");
1647   }
1648
1649   { // INST_RET abbrev for FUNCTION_BLOCK.
1650     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1651     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1652     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1653                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1654       llvm_unreachable("Unexpected abbrev ordering!");
1655   }
1656   { // INST_RET abbrev for FUNCTION_BLOCK.
1657     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1658     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1659     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1660     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1661                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1662       llvm_unreachable("Unexpected abbrev ordering!");
1663   }
1664   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1665     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1666     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1667     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1668                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1669       llvm_unreachable("Unexpected abbrev ordering!");
1670   }
1671
1672   Stream.ExitBlock();
1673 }
1674
1675 // Sort the Users based on the order in which the reader parses the bitcode
1676 // file.
1677 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1678   // TODO: Implement.
1679   return true;
1680 }
1681
1682 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1683                          BitstreamWriter &Stream) {
1684
1685   // One or zero uses can't get out of order.
1686   if (V->use_empty() || V->hasNUses(1))
1687     return;
1688
1689   // Make a copy of the in-memory use-list for sorting.
1690   unsigned UseListSize = std::distance(V->use_begin(), V->use_end());
1691   SmallVector<const User*, 8> UseList;
1692   UseList.reserve(UseListSize);
1693   for (Value::const_use_iterator I = V->use_begin(), E = V->use_end();
1694        I != E; ++I) {
1695     const User *U = *I;
1696     UseList.push_back(U);
1697   }
1698
1699   // Sort the copy based on the order read by the BitcodeReader.
1700   std::sort(UseList.begin(), UseList.end(), bitcodereader_order);
1701
1702   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1703   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1704
1705   // TODO: Emit the USELIST_CODE_ENTRYs.
1706 }
1707
1708 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1709                                  BitstreamWriter &Stream) {
1710   VE.incorporateFunction(*F);
1711
1712   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1713        AI != AE; ++AI)
1714     WriteUseList(AI, VE, Stream);
1715   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1716        ++BB) {
1717     WriteUseList(BB, VE, Stream);
1718     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1719          ++II) {
1720       WriteUseList(II, VE, Stream);
1721       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1722            OI != E; ++OI) {
1723         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1724             isa<InlineAsm>(*OI))
1725           WriteUseList(*OI, VE, Stream);
1726       }
1727     }
1728   }
1729   VE.purgeFunction();
1730 }
1731
1732 // Emit use-lists.
1733 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1734                                 BitstreamWriter &Stream) {
1735   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1736
1737   // XXX: this modifies the module, but in a way that should never change the
1738   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1739   // contain entries in the use_list that do not exist in the Module and are
1740   // not stored in the .bc file.
1741   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1742        I != E; ++I)
1743     I->removeDeadConstantUsers();
1744
1745   // Write the global variables.
1746   for (Module::const_global_iterator GI = M->global_begin(),
1747          GE = M->global_end(); GI != GE; ++GI) {
1748     WriteUseList(GI, VE, Stream);
1749
1750     // Write the global variable initializers.
1751     if (GI->hasInitializer())
1752       WriteUseList(GI->getInitializer(), VE, Stream);
1753   }
1754
1755   // Write the functions.
1756   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1757     WriteUseList(FI, VE, Stream);
1758     if (!FI->isDeclaration())
1759       WriteFunctionUseList(FI, VE, Stream);
1760   }
1761
1762   // Write the aliases.
1763   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1764        AI != AE; ++AI) {
1765     WriteUseList(AI, VE, Stream);
1766     WriteUseList(AI->getAliasee(), VE, Stream);
1767   }
1768
1769   Stream.ExitBlock();
1770 }
1771
1772 /// WriteModule - Emit the specified module to the bitstream.
1773 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1774   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1775
1776   // Emit the version number if it is non-zero.
1777   if (CurVersion) {
1778     SmallVector<unsigned, 1> Vals;
1779     Vals.push_back(CurVersion);
1780     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1781   }
1782
1783   // Analyze the module, enumerating globals, functions, etc.
1784   ValueEnumerator VE(M);
1785
1786   // Emit blockinfo, which defines the standard abbreviations etc.
1787   WriteBlockInfo(VE, Stream);
1788
1789   // Emit information about parameter attributes.
1790   WriteAttributeTable(VE, Stream);
1791
1792   // Emit information describing all of the types in the module.
1793   WriteTypeTable(VE, Stream);
1794
1795   // Emit top-level description of module, including target triple, inline asm,
1796   // descriptors for global variables, and function prototype info.
1797   WriteModuleInfo(M, VE, Stream);
1798
1799   // Emit constants.
1800   WriteModuleConstants(VE, Stream);
1801
1802   // Emit metadata.
1803   WriteModuleMetadata(M, VE, Stream);
1804
1805   // Emit metadata.
1806   WriteModuleMetadataStore(M, Stream);
1807
1808   // Emit names for globals/functions etc.
1809   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1810
1811   // Emit use-lists.
1812   if (EnablePreserveUseListOrdering)
1813     WriteModuleUseLists(M, VE, Stream);
1814
1815   // Emit function bodies.
1816   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1817     if (!F->isDeclaration())
1818       WriteFunction(*F, VE, Stream);
1819
1820   Stream.ExitBlock();
1821 }
1822
1823 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1824 /// header and trailer to make it compatible with the system archiver.  To do
1825 /// this we emit the following header, and then emit a trailer that pads the
1826 /// file out to be a multiple of 16 bytes.
1827 ///
1828 /// struct bc_header {
1829 ///   uint32_t Magic;         // 0x0B17C0DE
1830 ///   uint32_t Version;       // Version, currently always 0.
1831 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1832 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1833 ///   uint32_t CPUType;       // CPU specifier.
1834 ///   ... potentially more later ...
1835 /// };
1836 enum {
1837   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1838   DarwinBCHeaderSize = 5*4
1839 };
1840
1841 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1842                                uint32_t &Position) {
1843   Buffer[Position + 0] = (unsigned char) (Value >>  0);
1844   Buffer[Position + 1] = (unsigned char) (Value >>  8);
1845   Buffer[Position + 2] = (unsigned char) (Value >> 16);
1846   Buffer[Position + 3] = (unsigned char) (Value >> 24);
1847   Position += 4;
1848 }
1849
1850 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1851                                          const Triple &TT) {
1852   unsigned CPUType = ~0U;
1853
1854   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1855   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1856   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1857   // specific constants here because they are implicitly part of the Darwin ABI.
1858   enum {
1859     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1860     DARWIN_CPU_TYPE_X86        = 7,
1861     DARWIN_CPU_TYPE_ARM        = 12,
1862     DARWIN_CPU_TYPE_POWERPC    = 18
1863   };
1864
1865   Triple::ArchType Arch = TT.getArch();
1866   if (Arch == Triple::x86_64)
1867     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1868   else if (Arch == Triple::x86)
1869     CPUType = DARWIN_CPU_TYPE_X86;
1870   else if (Arch == Triple::ppc)
1871     CPUType = DARWIN_CPU_TYPE_POWERPC;
1872   else if (Arch == Triple::ppc64)
1873     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1874   else if (Arch == Triple::arm || Arch == Triple::thumb)
1875     CPUType = DARWIN_CPU_TYPE_ARM;
1876
1877   // Traditional Bitcode starts after header.
1878   assert(Buffer.size() >= DarwinBCHeaderSize &&
1879          "Expected header size to be reserved");
1880   unsigned BCOffset = DarwinBCHeaderSize;
1881   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
1882
1883   // Write the magic and version.
1884   unsigned Position = 0;
1885   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
1886   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
1887   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
1888   WriteInt32ToBuffer(BCSize     , Buffer, Position);
1889   WriteInt32ToBuffer(CPUType    , Buffer, Position);
1890
1891   // If the file is not a multiple of 16 bytes, insert dummy padding.
1892   while (Buffer.size() & 15)
1893     Buffer.push_back(0);
1894 }
1895
1896 /// WriteBitcodeToFile - Write the specified module to the specified output
1897 /// stream.
1898 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1899   SmallVector<char, 1024> Buffer;
1900   Buffer.reserve(256*1024);
1901
1902   // If this is darwin or another generic macho target, reserve space for the
1903   // header.
1904   Triple TT(M->getTargetTriple());
1905   if (TT.isOSDarwin())
1906     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
1907
1908   // Emit the module into the buffer.
1909   {
1910     BitstreamWriter Stream(Buffer);
1911
1912     // Emit the file header.
1913     Stream.Emit((unsigned)'B', 8);
1914     Stream.Emit((unsigned)'C', 8);
1915     Stream.Emit(0x0, 4);
1916     Stream.Emit(0xC, 4);
1917     Stream.Emit(0xE, 4);
1918     Stream.Emit(0xD, 4);
1919
1920     // Emit the module.
1921     WriteModule(M, Stream);
1922   }
1923
1924   if (TT.isOSDarwin())
1925     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
1926
1927   // Write the generated bitstream to "Out".
1928   Out.write((char*)&Buffer.front(), Buffer.size());
1929 }