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/Metadata.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/Operator.h"
  25 #include "llvm/TypeSymbolTable.h"
  26 #include "llvm/ValueSymbolTable.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/System/Program.h"
  31 using namespace llvm;
  32
  33 /// These are manifest constants used by the bitcode writer. They do not need to
  34 /// be kept in sync with the reader, but need to be consistent within this file.
  35 enum {
  36   CurVersion = 0,
  37
  38   // VALUE_SYMTAB_BLOCK abbrev id's.
  39   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  40   VST_ENTRY_7_ABBREV,
  41   VST_ENTRY_6_ABBREV,
  42   VST_BBENTRY_6_ABBREV,
  43
  44   // CONSTANTS_BLOCK abbrev id's.
  45   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  46   CONSTANTS_INTEGER_ABBREV,
  47   CONSTANTS_CE_CAST_Abbrev,
  48   CONSTANTS_NULL_Abbrev,
  49
  50   // FUNCTION_BLOCK abbrev id's.
  51   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  52   FUNCTION_INST_BINOP_ABBREV,
  53   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  54   FUNCTION_INST_CAST_ABBREV,
  55   FUNCTION_INST_RET_VOID_ABBREV,
  56   FUNCTION_INST_RET_VAL_ABBREV,
  57   FUNCTION_INST_UNREACHABLE_ABBREV
  58 };
  59
  60
  61 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  62   switch (Opcode) {
  63   default: llvm_unreachable("Unknown cast instruction!");
  64   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  65   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  66   case Instruction::SExt    : return bitc::CAST_SEXT;
  67   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  68   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  69   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  70   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  71   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  72   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  73   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  74   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  75   case Instruction::BitCast : return bitc::CAST_BITCAST;
  76   }
  77 }
  78
  79 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  80   switch (Opcode) {
  81   default: llvm_unreachable("Unknown binary instruction!");
  82   case Instruction::Add:
  83   case Instruction::FAdd: return bitc::BINOP_ADD;
  84   case Instruction::Sub:
  85   case Instruction::FSub: return bitc::BINOP_SUB;
  86   case Instruction::Mul:
  87   case Instruction::FMul: return bitc::BINOP_MUL;
  88   case Instruction::UDiv: return bitc::BINOP_UDIV;
  89   case Instruction::FDiv:
  90   case Instruction::SDiv: return bitc::BINOP_SDIV;
  91   case Instruction::URem: return bitc::BINOP_UREM;
  92   case Instruction::FRem:
  93   case Instruction::SRem: return bitc::BINOP_SREM;
  94   case Instruction::Shl:  return bitc::BINOP_SHL;
  95   case Instruction::LShr: return bitc::BINOP_LSHR;
  96   case Instruction::AShr: return bitc::BINOP_ASHR;
  97   case Instruction::And:  return bitc::BINOP_AND;
  98   case Instruction::Or:   return bitc::BINOP_OR;
  99   case Instruction::Xor:  return bitc::BINOP_XOR;
 100   }
 101 }
 102
 103
 104
 105 static void WriteStringRecord(unsigned Code, const std::string &Str,
 106                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 107   SmallVector<unsigned, 64> Vals;
 108
 109   // Code: [strchar x N]
 110   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 111     Vals.push_back(Str[i]);
 112
 113   // Emit the finished record.
 114   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 115 }
 116
 117 // Emit information about parameter attributes.
 118 static void WriteAttributeTable(const ValueEnumerator &VE,
 119                                 BitstreamWriter &Stream) {
 120   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 121   if (Attrs.empty()) return;
 122
 123   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 124
 125   SmallVector<uint64_t, 64> Record;
 126   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 127     const AttrListPtr &A = Attrs[i];
 128     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 129       const AttributeWithIndex &PAWI = A.getSlot(i);
 130       Record.push_back(PAWI.Index);
 131
 132       // FIXME: remove in LLVM 3.0
 133       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 134       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 135       // 11 bits.
 136       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 137       if (PAWI.Attrs & Attribute::Alignment)
 138         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 139       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 140
 141       Record.push_back(FauxAttr);
 142     }
 143
 144     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 145     Record.clear();
 146   }
 147
 148   Stream.ExitBlock();
 149 }
 150
 151 /// WriteTypeTable - Write out the type table for a module.
 152 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 153   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 154
 155   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 156   SmallVector<uint64_t, 64> TypeVals;
 157
 158   // Abbrev for TYPE_CODE_POINTER.
 159   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 160   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 162                             Log2_32_Ceil(VE.getTypes().size()+1)));
 163   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 164   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 165
 166   // Abbrev for TYPE_CODE_FUNCTION.
 167   Abbv = new BitCodeAbbrev();
 168   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 170   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 173                             Log2_32_Ceil(VE.getTypes().size()+1)));
 174   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 175
 176   // Abbrev for TYPE_CODE_STRUCT.
 177   Abbv = new BitCodeAbbrev();
 178   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 182                             Log2_32_Ceil(VE.getTypes().size()+1)));
 183   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 184
 185   // Abbrev for TYPE_CODE_ARRAY.
 186   Abbv = new BitCodeAbbrev();
 187   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 190                             Log2_32_Ceil(VE.getTypes().size()+1)));
 191   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 192
 193   // Emit an entry count so the reader can reserve space.
 194   TypeVals.push_back(TypeList.size());
 195   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 196   TypeVals.clear();
 197
 198   // Loop over all of the types, emitting each in turn.
 199   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 200     const Type *T = TypeList[i].first;
 201     int AbbrevToUse = 0;
 202     unsigned Code = 0;
 203
 204     switch (T->getTypeID()) {
 205     default: llvm_unreachable("Unknown type!");
 206     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 207     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 208     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 209     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 210     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 211     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 212     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 213     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 214     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 215     case Type::IntegerTyID:
 216       // INTEGER: [width]
 217       Code = bitc::TYPE_CODE_INTEGER;
 218       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 219       break;
 220     case Type::PointerTyID: {
 221       const PointerType *PTy = cast<PointerType>(T);
 222       // POINTER: [pointee type, address space]
 223       Code = bitc::TYPE_CODE_POINTER;
 224       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 225       unsigned AddressSpace = PTy->getAddressSpace();
 226       TypeVals.push_back(AddressSpace);
 227       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 228       break;
 229     }
 230     case Type::FunctionTyID: {
 231       const FunctionType *FT = cast<FunctionType>(T);
 232       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 233       Code = bitc::TYPE_CODE_FUNCTION;
 234       TypeVals.push_back(FT->isVarArg());
 235       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 236       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 237       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 238         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 239       AbbrevToUse = FunctionAbbrev;
 240       break;
 241     }
 242     case Type::StructTyID: {
 243       const StructType *ST = cast<StructType>(T);
 244       // STRUCT: [ispacked, eltty x N]
 245       Code = bitc::TYPE_CODE_STRUCT;
 246       TypeVals.push_back(ST->isPacked());
 247       // Output all of the element types.
 248       for (StructType::element_iterator I = ST->element_begin(),
 249            E = ST->element_end(); I != E; ++I)
 250         TypeVals.push_back(VE.getTypeID(*I));
 251       AbbrevToUse = StructAbbrev;
 252       break;
 253     }
 254     case Type::ArrayTyID: {
 255       const ArrayType *AT = cast<ArrayType>(T);
 256       // ARRAY: [numelts, eltty]
 257       Code = bitc::TYPE_CODE_ARRAY;
 258       TypeVals.push_back(AT->getNumElements());
 259       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 260       AbbrevToUse = ArrayAbbrev;
 261       break;
 262     }
 263     case Type::VectorTyID: {
 264       const VectorType *VT = cast<VectorType>(T);
 265       // VECTOR [numelts, eltty]
 266       Code = bitc::TYPE_CODE_VECTOR;
 267       TypeVals.push_back(VT->getNumElements());
 268       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 269       break;
 270     }
 271     }
 272
 273     // Emit the finished record.
 274     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 275     TypeVals.clear();
 276   }
 277
 278   Stream.ExitBlock();
 279 }
 280
 281 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 282   switch (GV->getLinkage()) {
 283   default: llvm_unreachable("Invalid linkage!");
 284   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 285   case GlobalValue::ExternalLinkage:            return 0;
 286   case GlobalValue::WeakAnyLinkage:             return 1;
 287   case GlobalValue::AppendingLinkage:           return 2;
 288   case GlobalValue::InternalLinkage:            return 3;
 289   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 290   case GlobalValue::DLLImportLinkage:           return 5;
 291   case GlobalValue::DLLExportLinkage:           return 6;
 292   case GlobalValue::ExternalWeakLinkage:        return 7;
 293   case GlobalValue::CommonLinkage:              return 8;
 294   case GlobalValue::PrivateLinkage:             return 9;
 295   case GlobalValue::WeakODRLinkage:             return 10;
 296   case GlobalValue::LinkOnceODRLinkage:         return 11;
 297   case GlobalValue::AvailableExternallyLinkage: return 12;
 298   case GlobalValue::LinkerPrivateLinkage:       return 13;
 299   }
 300 }
 301
 302 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 303   switch (GV->getVisibility()) {
 304   default: llvm_unreachable("Invalid visibility!");
 305   case GlobalValue::DefaultVisibility:   return 0;
 306   case GlobalValue::HiddenVisibility:    return 1;
 307   case GlobalValue::ProtectedVisibility: return 2;
 308   }
 309 }
 310
 311 // Emit top-level description of module, including target triple, inline asm,
 312 // descriptors for global variables, and function prototype info.
 313 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 314                             BitstreamWriter &Stream) {
 315   // Emit the list of dependent libraries for the Module.
 316   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 317     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 318
 319   // Emit various pieces of data attached to a module.
 320   if (!M->getTargetTriple().empty())
 321     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 322                       0/*TODO*/, Stream);
 323   if (!M->getDataLayout().empty())
 324     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 325                       0/*TODO*/, Stream);
 326   if (!M->getModuleInlineAsm().empty())
 327     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 328                       0/*TODO*/, Stream);
 329
 330   // Emit information about sections and GC, computing how many there are. Also
 331   // compute the maximum alignment value.
 332   std::map<std::string, unsigned> SectionMap;
 333   std::map<std::string, unsigned> GCMap;
 334   unsigned MaxAlignment = 0;
 335   unsigned MaxGlobalType = 0;
 336   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 337        GV != E; ++GV) {
 338     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 339     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 340
 341     if (!GV->hasSection()) continue;
 342     // Give section names unique ID's.
 343     unsigned &Entry = SectionMap[GV->getSection()];
 344     if (Entry != 0) continue;
 345     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 346                       0/*TODO*/, Stream);
 347     Entry = SectionMap.size();
 348   }
 349   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 350     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 351     if (F->hasSection()) {
 352       // Give section names unique ID's.
 353       unsigned &Entry = SectionMap[F->getSection()];
 354       if (!Entry) {
 355         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 356                           0/*TODO*/, Stream);
 357         Entry = SectionMap.size();
 358       }
 359     }
 360     if (F->hasGC()) {
 361       // Same for GC names.
 362       unsigned &Entry = GCMap[F->getGC()];
 363       if (!Entry) {
 364         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 365                           0/*TODO*/, Stream);
 366         Entry = GCMap.size();
 367       }
 368     }
 369   }
 370
 371   // Emit abbrev for globals, now that we know # sections and max alignment.
 372   unsigned SimpleGVarAbbrev = 0;
 373   if (!M->global_empty()) {
 374     // Add an abbrev for common globals with no visibility or thread localness.
 375     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 376     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 378                               Log2_32_Ceil(MaxGlobalType+1)));
 379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 382     if (MaxAlignment == 0)                                      // Alignment.
 383       Abbv->Add(BitCodeAbbrevOp(0));
 384     else {
 385       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 386       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 387                                Log2_32_Ceil(MaxEncAlignment+1)));
 388     }
 389     if (SectionMap.empty())                                    // Section.
 390       Abbv->Add(BitCodeAbbrevOp(0));
 391     else
 392       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 393                                Log2_32_Ceil(SectionMap.size()+1)));
 394     // Don't bother emitting vis + thread local.
 395     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 396   }
 397
 398   // Emit the global variable information.
 399   SmallVector<unsigned, 64> Vals;
 400   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 401        GV != E; ++GV) {
 402     unsigned AbbrevToUse = 0;
 403
 404     // GLOBALVAR: [type, isconst, initid,
 405     //             linkage, alignment, section, visibility, threadlocal]
 406     Vals.push_back(VE.getTypeID(GV->getType()));
 407     Vals.push_back(GV->isConstant());
 408     Vals.push_back(GV->isDeclaration() ? 0 :
 409                    (VE.getValueID(GV->getInitializer()) + 1));
 410     Vals.push_back(getEncodedLinkage(GV));
 411     Vals.push_back(Log2_32(GV->getAlignment())+1);
 412     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 413     if (GV->isThreadLocal() ||
 414         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 415       Vals.push_back(getEncodedVisibility(GV));
 416       Vals.push_back(GV->isThreadLocal());
 417     } else {
 418       AbbrevToUse = SimpleGVarAbbrev;
 419     }
 420
 421     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 422     Vals.clear();
 423   }
 424
 425   // Emit the function proto information.
 426   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 427     // FUNCTION:  [type, callingconv, isproto, paramattr,
 428     //             linkage, alignment, section, visibility, gc]
 429     Vals.push_back(VE.getTypeID(F->getType()));
 430     Vals.push_back(F->getCallingConv());
 431     Vals.push_back(F->isDeclaration());
 432     Vals.push_back(getEncodedLinkage(F));
 433     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 434     Vals.push_back(Log2_32(F->getAlignment())+1);
 435     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 436     Vals.push_back(getEncodedVisibility(F));
 437     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 438
 439     unsigned AbbrevToUse = 0;
 440     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 441     Vals.clear();
 442   }
 443
 444
 445   // Emit the alias information.
 446   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 447        AI != E; ++AI) {
 448     Vals.push_back(VE.getTypeID(AI->getType()));
 449     Vals.push_back(VE.getValueID(AI->getAliasee()));
 450     Vals.push_back(getEncodedLinkage(AI));
 451     Vals.push_back(getEncodedVisibility(AI));
 452     unsigned AbbrevToUse = 0;
 453     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 454     Vals.clear();
 455   }
 456 }
 457
 458 static uint64_t GetOptimizationFlags(const Value *V) {
 459   uint64_t Flags = 0;
 460
 461   if (const OverflowingBinaryOperator *OBO =
 462         dyn_cast<OverflowingBinaryOperator>(V)) {
 463     if (OBO->hasNoSignedWrap())
 464       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 465     if (OBO->hasNoUnsignedWrap())
 466       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 467   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 468     if (Div->isExact())
 469       Flags |= 1 << bitc::SDIV_EXACT;
 470   }
 471
 472   return Flags;
 473 }
 474
 475 static void WriteMDNode(const MDNode *N,
 476                         const ValueEnumerator &VE,
 477                         BitstreamWriter &Stream,
 478                         SmallVector<uint64_t, 64> &Record) {
 479   for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 480     if (N->getElement(i)) {
 481       Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 482       Record.push_back(VE.getValueID(N->getElement(i)));
 483     } else {
 484       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 485       Record.push_back(0);
 486     }
 487   }
 488   Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
 489   Record.clear();
 490 }
 491
 492 static void WriteModuleMetadata(const ValueEnumerator &VE,
 493                                 BitstreamWriter &Stream) {
 494   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 495   bool StartedMetadataBlock = false;
 496   unsigned MDSAbbrev = 0;
 497   SmallVector<uint64_t, 64> Record;
 498   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 499
 500     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 501       if (!StartedMetadataBlock) {
 502         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 503         StartedMetadataBlock = true;
 504       }
 505       WriteMDNode(N, VE, Stream, Record);
 506     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 507       if (!StartedMetadataBlock)  {
 508         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 509
 510         // Abbrev for METADATA_STRING.
 511         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 512         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 513         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 514         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 515         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 516         StartedMetadataBlock = true;
 517       }
 518
 519       // Code: [strchar x N]
 520       Record.append(MDS->begin(), MDS->end());
 521
 522       // Emit the finished record.
 523       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 524       Record.clear();
 525     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 526       if (!StartedMetadataBlock)  {
 527         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 528         StartedMetadataBlock = true;
 529       }
 530
 531       // Write name.
 532       std::string Str = NMD->getNameStr();
 533       const char *StrBegin = Str.c_str();
 534       for (unsigned i = 0, e = Str.length(); i != e; ++i)
 535         Record.push_back(StrBegin[i]);
 536       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 537       Record.clear();
 538
 539       // Write named metadata elements.
 540       for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
 541         if (NMD->getElement(i))
 542           Record.push_back(VE.getValueID(NMD->getElement(i)));
 543         else
 544           Record.push_back(0);
 545       }
 546       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 547       Record.clear();
 548     }
 549   }
 550
 551   if (StartedMetadataBlock)
 552     Stream.ExitBlock();
 553 }
 554
 555 static void WriteMetadataAttachment(const Function &F,
 556                                     const ValueEnumerator &VE,
 557                                     BitstreamWriter &Stream) {
 558   bool StartedMetadataBlock = false;
 559   SmallVector<uint64_t, 64> Record;
 560
 561   // Write metadata attachments
 562   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 563   MetadataContext &TheMetadata = F.getContext().getMetadata();
 564   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 565     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 566          I != E; ++I) {
 567       const MetadataContext::MDMapTy *P = TheMetadata.getMDs(I);
 568       if (!P) continue;
 569       bool RecordedInstruction = false;
 570       for (MetadataContext::MDMapTy::const_iterator PI = P->begin(),
 571              PE = P->end(); PI != PE; ++PI) {
 572         if (MDNode *ND = dyn_cast_or_null<MDNode>(PI->second)) {
 573           if (RecordedInstruction == false) {
 574             Record.push_back(VE.getInstructionID(I));
 575             RecordedInstruction = true;
 576           }
 577           Record.push_back(PI->first);
 578           Record.push_back(VE.getValueID(ND));
 579         }
 580       }
 581       if (!Record.empty()) {
 582         if (!StartedMetadataBlock)  {
 583           Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 584           StartedMetadataBlock = true;
 585         }
 586         Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 587         Record.clear();
 588       }
 589     }
 590
 591   if (StartedMetadataBlock)
 592     Stream.ExitBlock();
 593 }
 594
 595 static void WriteModuleMetadataStore(const Module *M,
 596                                      const ValueEnumerator &VE,
 597                                      BitstreamWriter &Stream) {
 598
 599   bool StartedMetadataBlock = false;
 600   SmallVector<uint64_t, 64> Record;
 601
 602   // Write metadata kinds
 603   // METADATA_KIND - [n x [id, name]]
 604   MetadataContext &TheMetadata = M->getContext().getMetadata();
 605   const StringMap<unsigned> *Kinds = TheMetadata.getHandlerNames();
 606   for (StringMap<unsigned>::const_iterator
 607          I = Kinds->begin(), E = Kinds->end(); I != E; ++I) {
 608     Record.push_back(I->second);
 609     StringRef KName = I->first();
 610     for (unsigned i = 0, e = KName.size(); i != e; ++i)
 611       Record.push_back(KName[i]);
 612     if (!StartedMetadataBlock)  {
 613       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 614       StartedMetadataBlock = true;
 615     }
 616     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 617     Record.clear();
 618   }
 619
 620   if (StartedMetadataBlock)
 621     Stream.ExitBlock();
 622 }
 623
 624 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 625                            const ValueEnumerator &VE,
 626                            BitstreamWriter &Stream, bool isGlobal) {
 627   if (FirstVal == LastVal) return;
 628
 629   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 630
 631   unsigned AggregateAbbrev = 0;
 632   unsigned String8Abbrev = 0;
 633   unsigned CString7Abbrev = 0;
 634   unsigned CString6Abbrev = 0;
 635   // If this is a constant pool for the module, emit module-specific abbrevs.
 636   if (isGlobal) {
 637     // Abbrev for CST_CODE_AGGREGATE.
 638     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 639     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 640     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 642     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 643
 644     // Abbrev for CST_CODE_STRING.
 645     Abbv = new BitCodeAbbrev();
 646     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 647     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 649     String8Abbrev = Stream.EmitAbbrev(Abbv);
 650     // Abbrev for CST_CODE_CSTRING.
 651     Abbv = new BitCodeAbbrev();
 652     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 653     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 654     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 655     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 656     // Abbrev for CST_CODE_CSTRING.
 657     Abbv = new BitCodeAbbrev();
 658     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 659     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 660     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 661     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 662   }
 663
 664   SmallVector<uint64_t, 64> Record;
 665
 666   const ValueEnumerator::ValueList &Vals = VE.getValues();
 667   const Type *LastTy = 0;
 668   for (unsigned i = FirstVal; i != LastVal; ++i) {
 669     const Value *V = Vals[i].first;
 670     // If we need to switch types, do so now.
 671     if (V->getType() != LastTy) {
 672       LastTy = V->getType();
 673       Record.push_back(VE.getTypeID(LastTy));
 674       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 675                         CONSTANTS_SETTYPE_ABBREV);
 676       Record.clear();
 677     }
 678
 679     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 680       Record.push_back(unsigned(IA->hasSideEffects()) |
 681                        unsigned(IA->isMsAsm()) << 1);
 682
 683       // Add the asm string.
 684       const std::string &AsmStr = IA->getAsmString();
 685       Record.push_back(AsmStr.size());
 686       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 687         Record.push_back(AsmStr[i]);
 688
 689       // Add the constraint string.
 690       const std::string &ConstraintStr = IA->getConstraintString();
 691       Record.push_back(ConstraintStr.size());
 692       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 693         Record.push_back(ConstraintStr[i]);
 694       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 695       Record.clear();
 696       continue;
 697     }
 698     const Constant *C = cast<Constant>(V);
 699     unsigned Code = -1U;
 700     unsigned AbbrevToUse = 0;
 701     if (C->isNullValue()) {
 702       Code = bitc::CST_CODE_NULL;
 703     } else if (isa<UndefValue>(C)) {
 704       Code = bitc::CST_CODE_UNDEF;
 705     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 706       if (IV->getBitWidth() <= 64) {
 707         int64_t V = IV->getSExtValue();
 708         if (V >= 0)
 709           Record.push_back(V << 1);
 710         else
 711           Record.push_back((-V << 1) | 1);
 712         Code = bitc::CST_CODE_INTEGER;
 713         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 714       } else {                             // Wide integers, > 64 bits in size.
 715         // We have an arbitrary precision integer value to write whose
 716         // bit width is > 64. However, in canonical unsigned integer
 717         // format it is likely that the high bits are going to be zero.
 718         // So, we only write the number of active words.
 719         unsigned NWords = IV->getValue().getActiveWords();
 720         const uint64_t *RawWords = IV->getValue().getRawData();
 721         for (unsigned i = 0; i != NWords; ++i) {
 722           int64_t V = RawWords[i];
 723           if (V >= 0)
 724             Record.push_back(V << 1);
 725           else
 726             Record.push_back((-V << 1) | 1);
 727         }
 728         Code = bitc::CST_CODE_WIDE_INTEGER;
 729       }
 730     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 731       Code = bitc::CST_CODE_FLOAT;
 732       const Type *Ty = CFP->getType();
 733       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 734         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 735       } else if (Ty->isX86_FP80Ty()) {
 736         // api needed to prevent premature destruction
 737         // bits are not in the same order as a normal i80 APInt, compensate.
 738         APInt api = CFP->getValueAPF().bitcastToAPInt();
 739         const uint64_t *p = api.getRawData();
 740         Record.push_back((p[1] << 48) | (p[0] >> 16));
 741         Record.push_back(p[0] & 0xffffLL);
 742       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 743         APInt api = CFP->getValueAPF().bitcastToAPInt();
 744         const uint64_t *p = api.getRawData();
 745         Record.push_back(p[0]);
 746         Record.push_back(p[1]);
 747       } else {
 748         assert (0 && "Unknown FP type!");
 749       }
 750     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 751       // Emit constant strings specially.
 752       unsigned NumOps = C->getNumOperands();
 753       // If this is a null-terminated string, use the denser CSTRING encoding.
 754       if (C->getOperand(NumOps-1)->isNullValue()) {
 755         Code = bitc::CST_CODE_CSTRING;
 756         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 757       } else {
 758         Code = bitc::CST_CODE_STRING;
 759         AbbrevToUse = String8Abbrev;
 760       }
 761       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 762       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 763       for (unsigned i = 0; i != NumOps; ++i) {
 764         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 765         Record.push_back(V);
 766         isCStr7 &= (V & 128) == 0;
 767         if (isCStrChar6)
 768           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 769       }
 770
 771       if (isCStrChar6)
 772         AbbrevToUse = CString6Abbrev;
 773       else if (isCStr7)
 774         AbbrevToUse = CString7Abbrev;
 775     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 776                isa<ConstantVector>(V)) {
 777       Code = bitc::CST_CODE_AGGREGATE;
 778       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 779         Record.push_back(VE.getValueID(C->getOperand(i)));
 780       AbbrevToUse = AggregateAbbrev;
 781     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 782       switch (CE->getOpcode()) {
 783       default:
 784         if (Instruction::isCast(CE->getOpcode())) {
 785           Code = bitc::CST_CODE_CE_CAST;
 786           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 787           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 788           Record.push_back(VE.getValueID(C->getOperand(0)));
 789           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 790         } else {
 791           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 792           Code = bitc::CST_CODE_CE_BINOP;
 793           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 794           Record.push_back(VE.getValueID(C->getOperand(0)));
 795           Record.push_back(VE.getValueID(C->getOperand(1)));
 796           uint64_t Flags = GetOptimizationFlags(CE);
 797           if (Flags != 0)
 798             Record.push_back(Flags);
 799         }
 800         break;
 801       case Instruction::GetElementPtr:
 802         Code = bitc::CST_CODE_CE_GEP;
 803         if (cast<GEPOperator>(C)->isInBounds())
 804           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 805         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 806           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 807           Record.push_back(VE.getValueID(C->getOperand(i)));
 808         }
 809         break;
 810       case Instruction::Select:
 811         Code = bitc::CST_CODE_CE_SELECT;
 812         Record.push_back(VE.getValueID(C->getOperand(0)));
 813         Record.push_back(VE.getValueID(C->getOperand(1)));
 814         Record.push_back(VE.getValueID(C->getOperand(2)));
 815         break;
 816       case Instruction::ExtractElement:
 817         Code = bitc::CST_CODE_CE_EXTRACTELT;
 818         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 819         Record.push_back(VE.getValueID(C->getOperand(0)));
 820         Record.push_back(VE.getValueID(C->getOperand(1)));
 821         break;
 822       case Instruction::InsertElement:
 823         Code = bitc::CST_CODE_CE_INSERTELT;
 824         Record.push_back(VE.getValueID(C->getOperand(0)));
 825         Record.push_back(VE.getValueID(C->getOperand(1)));
 826         Record.push_back(VE.getValueID(C->getOperand(2)));
 827         break;
 828       case Instruction::ShuffleVector:
 829         // If the return type and argument types are the same, this is a
 830         // standard shufflevector instruction.  If the types are different,
 831         // then the shuffle is widening or truncating the input vectors, and
 832         // the argument type must also be encoded.
 833         if (C->getType() == C->getOperand(0)->getType()) {
 834           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 835         } else {
 836           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 837           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 838         }
 839         Record.push_back(VE.getValueID(C->getOperand(0)));
 840         Record.push_back(VE.getValueID(C->getOperand(1)));
 841         Record.push_back(VE.getValueID(C->getOperand(2)));
 842         break;
 843       case Instruction::ICmp:
 844       case Instruction::FCmp:
 845         Code = bitc::CST_CODE_CE_CMP;
 846         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 847         Record.push_back(VE.getValueID(C->getOperand(0)));
 848         Record.push_back(VE.getValueID(C->getOperand(1)));
 849         Record.push_back(CE->getPredicate());
 850         break;
 851       }
 852     } else {
 853       llvm_unreachable("Unknown constant!");
 854     }
 855     Stream.EmitRecord(Code, Record, AbbrevToUse);
 856     Record.clear();
 857   }
 858
 859   Stream.ExitBlock();
 860 }
 861
 862 static void WriteModuleConstants(const ValueEnumerator &VE,
 863                                  BitstreamWriter &Stream) {
 864   const ValueEnumerator::ValueList &Vals = VE.getValues();
 865
 866   // Find the first constant to emit, which is the first non-globalvalue value.
 867   // We know globalvalues have been emitted by WriteModuleInfo.
 868   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 869     if (!isa<GlobalValue>(Vals[i].first)) {
 870       WriteConstants(i, Vals.size(), VE, Stream, true);
 871       return;
 872     }
 873   }
 874 }
 875
 876 /// PushValueAndType - The file has to encode both the value and type id for
 877 /// many values, because we need to know what type to create for forward
 878 /// references.  However, most operands are not forward references, so this type
 879 /// field is not needed.
 880 ///
 881 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 882 /// instruction ID, then it is a forward reference, and it also includes the
 883 /// type ID.
 884 static bool PushValueAndType(const Value *V, unsigned InstID,
 885                              SmallVector<unsigned, 64> &Vals,
 886                              ValueEnumerator &VE) {
 887   unsigned ValID = VE.getValueID(V);
 888   Vals.push_back(ValID);
 889   if (ValID >= InstID) {
 890     Vals.push_back(VE.getTypeID(V->getType()));
 891     return true;
 892   }
 893   return false;
 894 }
 895
 896 /// WriteInstruction - Emit an instruction to the specified stream.
 897 static void WriteInstruction(const Instruction &I, unsigned InstID,
 898                              ValueEnumerator &VE, BitstreamWriter &Stream,
 899                              SmallVector<unsigned, 64> &Vals) {
 900   unsigned Code = 0;
 901   unsigned AbbrevToUse = 0;
 902   VE.setInstructionID(&I);
 903   switch (I.getOpcode()) {
 904   default:
 905     if (Instruction::isCast(I.getOpcode())) {
 906       Code = bitc::FUNC_CODE_INST_CAST;
 907       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 908         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 909       Vals.push_back(VE.getTypeID(I.getType()));
 910       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 911     } else {
 912       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 913       Code = bitc::FUNC_CODE_INST_BINOP;
 914       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 915         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 916       Vals.push_back(VE.getValueID(I.getOperand(1)));
 917       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 918       uint64_t Flags = GetOptimizationFlags(&I);
 919       if (Flags != 0) {
 920         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 921           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 922         Vals.push_back(Flags);
 923       }
 924     }
 925     break;
 926
 927   case Instruction::GetElementPtr:
 928     Code = bitc::FUNC_CODE_INST_GEP;
 929     if (cast<GEPOperator>(&I)->isInBounds())
 930       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 931     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 932       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 933     break;
 934   case Instruction::ExtractValue: {
 935     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 936     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 937     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 938     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 939       Vals.push_back(*i);
 940     break;
 941   }
 942   case Instruction::InsertValue: {
 943     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 944     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 945     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 946     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 947     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 948       Vals.push_back(*i);
 949     break;
 950   }
 951   case Instruction::Select:
 952     Code = bitc::FUNC_CODE_INST_VSELECT;
 953     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 954     Vals.push_back(VE.getValueID(I.getOperand(2)));
 955     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 956     break;
 957   case Instruction::ExtractElement:
 958     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 959     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 960     Vals.push_back(VE.getValueID(I.getOperand(1)));
 961     break;
 962   case Instruction::InsertElement:
 963     Code = bitc::FUNC_CODE_INST_INSERTELT;
 964     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 965     Vals.push_back(VE.getValueID(I.getOperand(1)));
 966     Vals.push_back(VE.getValueID(I.getOperand(2)));
 967     break;
 968   case Instruction::ShuffleVector:
 969     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 970     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 971     Vals.push_back(VE.getValueID(I.getOperand(1)));
 972     Vals.push_back(VE.getValueID(I.getOperand(2)));
 973     break;
 974   case Instruction::ICmp:
 975   case Instruction::FCmp:
 976     // compare returning Int1Ty or vector of Int1Ty
 977     Code = bitc::FUNC_CODE_INST_CMP2;
 978     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 979     Vals.push_back(VE.getValueID(I.getOperand(1)));
 980     Vals.push_back(cast<CmpInst>(I).getPredicate());
 981     break;
 982
 983   case Instruction::Ret:
 984     {
 985       Code = bitc::FUNC_CODE_INST_RET;
 986       unsigned NumOperands = I.getNumOperands();
 987       if (NumOperands == 0)
 988         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 989       else if (NumOperands == 1) {
 990         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 991           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 992       } else {
 993         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 994           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 995       }
 996     }
 997     break;
 998   case Instruction::Br:
 999     {
1000       Code = bitc::FUNC_CODE_INST_BR;
1001       BranchInst &II(cast<BranchInst>(I));
1002       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1003       if (II.isConditional()) {
1004         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1005         Vals.push_back(VE.getValueID(II.getCondition()));
1006       }
1007     }
1008     break;
1009   case Instruction::Switch:
1010     Code = bitc::FUNC_CODE_INST_SWITCH;
1011     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1012     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1013       Vals.push_back(VE.getValueID(I.getOperand(i)));
1014     break;
1015   case Instruction::Invoke: {
1016     const InvokeInst *II = cast<InvokeInst>(&I);
1017     const Value *Callee(II->getCalledValue());
1018     const PointerType *PTy = cast<PointerType>(Callee->getType());
1019     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1020     Code = bitc::FUNC_CODE_INST_INVOKE;
1021
1022     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1023     Vals.push_back(II->getCallingConv());
1024     Vals.push_back(VE.getValueID(II->getNormalDest()));
1025     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1026     PushValueAndType(Callee, InstID, Vals, VE);
1027
1028     // Emit value #'s for the fixed parameters.
1029     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1030       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1031
1032     // Emit type/value pairs for varargs params.
1033     if (FTy->isVarArg()) {
1034       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1035            i != e; ++i)
1036         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1037     }
1038     break;
1039   }
1040   case Instruction::Unwind:
1041     Code = bitc::FUNC_CODE_INST_UNWIND;
1042     break;
1043   case Instruction::Unreachable:
1044     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1045     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1046     break;
1047
1048   case Instruction::PHI:
1049     Code = bitc::FUNC_CODE_INST_PHI;
1050     Vals.push_back(VE.getTypeID(I.getType()));
1051     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1052       Vals.push_back(VE.getValueID(I.getOperand(i)));
1053     break;
1054
1055   case Instruction::Free:
1056     Code = bitc::FUNC_CODE_INST_FREE;
1057     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1058     break;
1059
1060   case Instruction::Alloca:
1061     Code = bitc::FUNC_CODE_INST_ALLOCA;
1062     Vals.push_back(VE.getTypeID(I.getType()));
1063     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1064     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1065     break;
1066
1067   case Instruction::Load:
1068     Code = bitc::FUNC_CODE_INST_LOAD;
1069     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1070       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1071
1072     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1073     Vals.push_back(cast<LoadInst>(I).isVolatile());
1074     break;
1075   case Instruction::Store:
1076     Code = bitc::FUNC_CODE_INST_STORE2;
1077     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1078     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1079     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1080     Vals.push_back(cast<StoreInst>(I).isVolatile());
1081     break;
1082   case Instruction::Call: {
1083     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1084     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1085
1086     Code = bitc::FUNC_CODE_INST_CALL;
1087
1088     const CallInst *CI = cast<CallInst>(&I);
1089     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1090     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1091     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1092
1093     // Emit value #'s for the fixed parameters.
1094     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1095       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1096
1097     // Emit type/value pairs for varargs params.
1098     if (FTy->isVarArg()) {
1099       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1100       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1101            i != e; ++i)
1102         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1103     }
1104     break;
1105   }
1106   case Instruction::VAArg:
1107     Code = bitc::FUNC_CODE_INST_VAARG;
1108     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1109     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1110     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1111     break;
1112   }
1113
1114   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1115   Vals.clear();
1116 }
1117
1118 // Emit names for globals/functions etc.
1119 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1120                                   const ValueEnumerator &VE,
1121                                   BitstreamWriter &Stream) {
1122   if (VST.empty()) return;
1123   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1124
1125   // FIXME: Set up the abbrev, we know how many values there are!
1126   // FIXME: We know if the type names can use 7-bit ascii.
1127   SmallVector<unsigned, 64> NameVals;
1128
1129   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1130        SI != SE; ++SI) {
1131
1132     const ValueName &Name = *SI;
1133
1134     // Figure out the encoding to use for the name.
1135     bool is7Bit = true;
1136     bool isChar6 = true;
1137     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1138          C != E; ++C) {
1139       if (isChar6)
1140         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1141       if ((unsigned char)*C & 128) {
1142         is7Bit = false;
1143         break;  // don't bother scanning the rest.
1144       }
1145     }
1146
1147     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1148
1149     // VST_ENTRY:   [valueid, namechar x N]
1150     // VST_BBENTRY: [bbid, namechar x N]
1151     unsigned Code;
1152     if (isa<BasicBlock>(SI->getValue())) {
1153       Code = bitc::VST_CODE_BBENTRY;
1154       if (isChar6)
1155         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1156     } else {
1157       Code = bitc::VST_CODE_ENTRY;
1158       if (isChar6)
1159         AbbrevToUse = VST_ENTRY_6_ABBREV;
1160       else if (is7Bit)
1161         AbbrevToUse = VST_ENTRY_7_ABBREV;
1162     }
1163
1164     NameVals.push_back(VE.getValueID(SI->getValue()));
1165     for (const char *P = Name.getKeyData(),
1166          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1167       NameVals.push_back((unsigned char)*P);
1168
1169     // Emit the finished record.
1170     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1171     NameVals.clear();
1172   }
1173   Stream.ExitBlock();
1174 }
1175
1176 /// WriteFunction - Emit a function body to the module stream.
1177 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1178                           BitstreamWriter &Stream) {
1179   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1180   VE.incorporateFunction(F);
1181
1182   SmallVector<unsigned, 64> Vals;
1183
1184   // Emit the number of basic blocks, so the reader can create them ahead of
1185   // time.
1186   Vals.push_back(VE.getBasicBlocks().size());
1187   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1188   Vals.clear();
1189
1190   // If there are function-local constants, emit them now.
1191   unsigned CstStart, CstEnd;
1192   VE.getFunctionConstantRange(CstStart, CstEnd);
1193   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1194
1195   // Keep a running idea of what the instruction ID is.
1196   unsigned InstID = CstEnd;
1197
1198   // Finally, emit all the instructions, in order.
1199   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1200     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1201          I != E; ++I) {
1202       WriteInstruction(*I, InstID, VE, Stream, Vals);
1203       if (I->getType() != Type::getVoidTy(F.getContext()))
1204         ++InstID;
1205     }
1206
1207   // Emit names for all the instructions etc.
1208   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1209
1210   WriteMetadataAttachment(F, VE, Stream);
1211   VE.purgeFunction();
1212   Stream.ExitBlock();
1213 }
1214
1215 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1216 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1217                                  const ValueEnumerator &VE,
1218                                  BitstreamWriter &Stream) {
1219   if (TST.empty()) return;
1220
1221   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1222
1223   // 7-bit fixed width VST_CODE_ENTRY strings.
1224   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1225   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1226   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1227                             Log2_32_Ceil(VE.getTypes().size()+1)));
1228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1230   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1231
1232   SmallVector<unsigned, 64> NameVals;
1233
1234   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1235        TI != TE; ++TI) {
1236     // TST_ENTRY: [typeid, namechar x N]
1237     NameVals.push_back(VE.getTypeID(TI->second));
1238
1239     const std::string &Str = TI->first;
1240     bool is7Bit = true;
1241     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1242       NameVals.push_back((unsigned char)Str[i]);
1243       if (Str[i] & 128)
1244         is7Bit = false;
1245     }
1246
1247     // Emit the finished record.
1248     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1249     NameVals.clear();
1250   }
1251
1252   Stream.ExitBlock();
1253 }
1254
1255 // Emit blockinfo, which defines the standard abbreviations etc.
1256 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1257   // We only want to emit block info records for blocks that have multiple
1258   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1259   // blocks can defined their abbrevs inline.
1260   Stream.EnterBlockInfoBlock(2);
1261
1262   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1263     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1268     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1269                                    Abbv) != VST_ENTRY_8_ABBREV)
1270       llvm_unreachable("Unexpected abbrev ordering!");
1271   }
1272
1273   { // 7-bit fixed width VST_ENTRY strings.
1274     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1275     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1279     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1280                                    Abbv) != VST_ENTRY_7_ABBREV)
1281       llvm_unreachable("Unexpected abbrev ordering!");
1282   }
1283   { // 6-bit char6 VST_ENTRY strings.
1284     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1285     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1289     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1290                                    Abbv) != VST_ENTRY_6_ABBREV)
1291       llvm_unreachable("Unexpected abbrev ordering!");
1292   }
1293   { // 6-bit char6 VST_BBENTRY strings.
1294     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1295     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1297     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1299     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1300                                    Abbv) != VST_BBENTRY_6_ABBREV)
1301       llvm_unreachable("Unexpected abbrev ordering!");
1302   }
1303
1304
1305
1306   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1307     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1308     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1310                               Log2_32_Ceil(VE.getTypes().size()+1)));
1311     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1312                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1313       llvm_unreachable("Unexpected abbrev ordering!");
1314   }
1315
1316   { // INTEGER abbrev for CONSTANTS_BLOCK.
1317     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1318     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1319     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1320     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1321                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1322       llvm_unreachable("Unexpected abbrev ordering!");
1323   }
1324
1325   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1326     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1327     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1328     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1330                               Log2_32_Ceil(VE.getTypes().size()+1)));
1331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1332
1333     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1334                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1335       llvm_unreachable("Unexpected abbrev ordering!");
1336   }
1337   { // NULL abbrev for CONSTANTS_BLOCK.
1338     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1339     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1340     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1341                                    Abbv) != CONSTANTS_NULL_Abbrev)
1342       llvm_unreachable("Unexpected abbrev ordering!");
1343   }
1344
1345   // FIXME: This should only use space for first class types!
1346
1347   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1348     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1349     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1353     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1354                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1355       llvm_unreachable("Unexpected abbrev ordering!");
1356   }
1357   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1358     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1359     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1361     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1362     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1363     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1364                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1365       llvm_unreachable("Unexpected abbrev ordering!");
1366   }
1367   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1368     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1369     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1374     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1375                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1376       llvm_unreachable("Unexpected abbrev ordering!");
1377   }
1378   { // INST_CAST abbrev for FUNCTION_BLOCK.
1379     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1380     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1383                               Log2_32_Ceil(VE.getTypes().size()+1)));
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1385     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1386                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1387       llvm_unreachable("Unexpected abbrev ordering!");
1388   }
1389
1390   { // INST_RET abbrev for FUNCTION_BLOCK.
1391     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1392     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1393     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1394                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1395       llvm_unreachable("Unexpected abbrev ordering!");
1396   }
1397   { // INST_RET abbrev for FUNCTION_BLOCK.
1398     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1399     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1400     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1401     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1402                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1403       llvm_unreachable("Unexpected abbrev ordering!");
1404   }
1405   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1406     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1407     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1408     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1409                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1410       llvm_unreachable("Unexpected abbrev ordering!");
1411   }
1412
1413   Stream.ExitBlock();
1414 }
1415
1416
1417 /// WriteModule - Emit the specified module to the bitstream.
1418 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1419   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1420
1421   // Emit the version number if it is non-zero.
1422   if (CurVersion) {
1423     SmallVector<unsigned, 1> Vals;
1424     Vals.push_back(CurVersion);
1425     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1426   }
1427
1428   // Analyze the module, enumerating globals, functions, etc.
1429   ValueEnumerator VE(M);
1430
1431   // Emit blockinfo, which defines the standard abbreviations etc.
1432   WriteBlockInfo(VE, Stream);
1433
1434   // Emit information about parameter attributes.
1435   WriteAttributeTable(VE, Stream);
1436
1437   // Emit information describing all of the types in the module.
1438   WriteTypeTable(VE, Stream);
1439
1440   // Emit top-level description of module, including target triple, inline asm,
1441   // descriptors for global variables, and function prototype info.
1442   WriteModuleInfo(M, VE, Stream);
1443
1444   // Emit constants.
1445   WriteModuleConstants(VE, Stream);
1446
1447   // Emit metadata.
1448   WriteModuleMetadata(VE, Stream);
1449
1450   // Emit function bodies.
1451   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1452     if (!I->isDeclaration())
1453       WriteFunction(*I, VE, Stream);
1454
1455   // Emit metadata.
1456   WriteModuleMetadataStore(M, VE, Stream);
1457
1458   // Emit the type symbol table information.
1459   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1460
1461   // Emit names for globals/functions etc.
1462   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1463
1464   Stream.ExitBlock();
1465 }
1466
1467 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1468 /// header and trailer to make it compatible with the system archiver.  To do
1469 /// this we emit the following header, and then emit a trailer that pads the
1470 /// file out to be a multiple of 16 bytes.
1471 ///
1472 /// struct bc_header {
1473 ///   uint32_t Magic;         // 0x0B17C0DE
1474 ///   uint32_t Version;       // Version, currently always 0.
1475 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1476 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1477 ///   uint32_t CPUType;       // CPU specifier.
1478 ///   ... potentially more later ...
1479 /// };
1480 enum {
1481   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1482   DarwinBCHeaderSize = 5*4
1483 };
1484
1485 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1486                                const std::string &TT) {
1487   unsigned CPUType = ~0U;
1488
1489   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1490   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1491   // specific constants here because they are implicitly part of the Darwin ABI.
1492   enum {
1493     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1494     DARWIN_CPU_TYPE_X86        = 7,
1495     DARWIN_CPU_TYPE_POWERPC    = 18
1496   };
1497
1498   if (TT.find("x86_64-") == 0)
1499     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1500   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1501            TT[4] == '-' && TT[1] - '3' < 6)
1502     CPUType = DARWIN_CPU_TYPE_X86;
1503   else if (TT.find("powerpc-") == 0)
1504     CPUType = DARWIN_CPU_TYPE_POWERPC;
1505   else if (TT.find("powerpc64-") == 0)
1506     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1507
1508   // Traditional Bitcode starts after header.
1509   unsigned BCOffset = DarwinBCHeaderSize;
1510
1511   Stream.Emit(0x0B17C0DE, 32);
1512   Stream.Emit(0         , 32);  // Version.
1513   Stream.Emit(BCOffset  , 32);
1514   Stream.Emit(0         , 32);  // Filled in later.
1515   Stream.Emit(CPUType   , 32);
1516 }
1517
1518 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1519 /// finalize the header.
1520 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1521   // Update the size field in the header.
1522   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1523
1524   // If the file is not a multiple of 16 bytes, insert dummy padding.
1525   while (BufferSize & 15) {
1526     Stream.Emit(0, 8);
1527     ++BufferSize;
1528   }
1529 }
1530
1531
1532 /// WriteBitcodeToFile - Write the specified module to the specified output
1533 /// stream.
1534 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1535   std::vector<unsigned char> Buffer;
1536   BitstreamWriter Stream(Buffer);
1537
1538   Buffer.reserve(256*1024);
1539
1540   WriteBitcodeToStream( M, Stream );
1541
1542   // If writing to stdout, set binary mode.
1543   if (&llvm::outs() == &Out)
1544     sys::Program::ChangeStdoutToBinary();
1545
1546   // Write the generated bitstream to "Out".
1547   Out.write((char*)&Buffer.front(), Buffer.size());
1548
1549   // Make sure it hits disk now.
1550   Out.flush();
1551 }
1552
1553 /// WriteBitcodeToStream - Write the specified module to the specified output
1554 /// stream.
1555 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1556   // If this is darwin, emit a file header and trailer if needed.
1557   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1558   if (isDarwin)
1559     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1560
1561   // Emit the file header.
1562   Stream.Emit((unsigned)'B', 8);
1563   Stream.Emit((unsigned)'C', 8);
1564   Stream.Emit(0x0, 4);
1565   Stream.Emit(0xC, 4);
1566   Stream.Emit(0xE, 4);
1567   Stream.Emit(0xD, 4);
1568
1569   // Emit the module.
1570   WriteModule(M, Stream);
1571
1572   if (isDarwin)
1573     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1574 }