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       const char *StrBegin = MDS->begin();
 521       for (unsigned i = 0, e = MDS->length(); i != e; ++i)
 522         Record.push_back(StrBegin[i]);
 523
 524       // Emit the finished record.
 525       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 526       Record.clear();
 527     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 528       if (!StartedMetadataBlock)  {
 529         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 530         StartedMetadataBlock = true;
 531       }
 532
 533       // Write name.
 534       std::string Str = NMD->getNameStr();
 535       const char *StrBegin = Str.c_str();
 536       for (unsigned i = 0, e = Str.length(); i != e; ++i)
 537         Record.push_back(StrBegin[i]);
 538       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 539       Record.clear();
 540
 541       // Write named metadata elements.
 542       for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
 543         if (NMD->getElement(i))
 544           Record.push_back(VE.getValueID(NMD->getElement(i)));
 545         else
 546           Record.push_back(0);
 547       }
 548       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 549       Record.clear();
 550     }
 551   }
 552
 553   if (StartedMetadataBlock)
 554     Stream.ExitBlock();
 555 }
 556
 557 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 558                            const ValueEnumerator &VE,
 559                            BitstreamWriter &Stream, bool isGlobal) {
 560   if (FirstVal == LastVal) return;
 561
 562   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 563
 564   unsigned AggregateAbbrev = 0;
 565   unsigned String8Abbrev = 0;
 566   unsigned CString7Abbrev = 0;
 567   unsigned CString6Abbrev = 0;
 568   // If this is a constant pool for the module, emit module-specific abbrevs.
 569   if (isGlobal) {
 570     // Abbrev for CST_CODE_AGGREGATE.
 571     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 572     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 573     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 574     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 575     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 576
 577     // Abbrev for CST_CODE_STRING.
 578     Abbv = new BitCodeAbbrev();
 579     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 582     String8Abbrev = Stream.EmitAbbrev(Abbv);
 583     // Abbrev for CST_CODE_CSTRING.
 584     Abbv = new BitCodeAbbrev();
 585     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 586     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 587     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 588     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 589     // Abbrev for CST_CODE_CSTRING.
 590     Abbv = new BitCodeAbbrev();
 591     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 594     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 595   }
 596
 597   SmallVector<uint64_t, 64> Record;
 598
 599   const ValueEnumerator::ValueList &Vals = VE.getValues();
 600   const Type *LastTy = 0;
 601   for (unsigned i = FirstVal; i != LastVal; ++i) {
 602     const Value *V = Vals[i].first;
 603     // If we need to switch types, do so now.
 604     if (V->getType() != LastTy) {
 605       LastTy = V->getType();
 606       Record.push_back(VE.getTypeID(LastTy));
 607       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 608                         CONSTANTS_SETTYPE_ABBREV);
 609       Record.clear();
 610     }
 611
 612     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 613       Record.push_back(unsigned(IA->hasSideEffects()));
 614
 615       // Add the asm string.
 616       const std::string &AsmStr = IA->getAsmString();
 617       Record.push_back(AsmStr.size());
 618       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 619         Record.push_back(AsmStr[i]);
 620
 621       // Add the constraint string.
 622       const std::string &ConstraintStr = IA->getConstraintString();
 623       Record.push_back(ConstraintStr.size());
 624       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 625         Record.push_back(ConstraintStr[i]);
 626       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 627       Record.clear();
 628       continue;
 629     }
 630     const Constant *C = cast<Constant>(V);
 631     unsigned Code = -1U;
 632     unsigned AbbrevToUse = 0;
 633     if (C->isNullValue()) {
 634       Code = bitc::CST_CODE_NULL;
 635     } else if (isa<UndefValue>(C)) {
 636       Code = bitc::CST_CODE_UNDEF;
 637     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 638       if (IV->getBitWidth() <= 64) {
 639         int64_t V = IV->getSExtValue();
 640         if (V >= 0)
 641           Record.push_back(V << 1);
 642         else
 643           Record.push_back((-V << 1) | 1);
 644         Code = bitc::CST_CODE_INTEGER;
 645         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 646       } else {                             // Wide integers, > 64 bits in size.
 647         // We have an arbitrary precision integer value to write whose
 648         // bit width is > 64. However, in canonical unsigned integer
 649         // format it is likely that the high bits are going to be zero.
 650         // So, we only write the number of active words.
 651         unsigned NWords = IV->getValue().getActiveWords();
 652         const uint64_t *RawWords = IV->getValue().getRawData();
 653         for (unsigned i = 0; i != NWords; ++i) {
 654           int64_t V = RawWords[i];
 655           if (V >= 0)
 656             Record.push_back(V << 1);
 657           else
 658             Record.push_back((-V << 1) | 1);
 659         }
 660         Code = bitc::CST_CODE_WIDE_INTEGER;
 661       }
 662     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 663       Code = bitc::CST_CODE_FLOAT;
 664       const Type *Ty = CFP->getType();
 665       if (Ty == Type::getFloatTy(Ty->getContext()) ||
 666           Ty == Type::getDoubleTy(Ty->getContext())) {
 667         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 668       } else if (Ty == Type::getX86_FP80Ty(Ty->getContext())) {
 669         // api needed to prevent premature destruction
 670         // bits are not in the same order as a normal i80 APInt, compensate.
 671         APInt api = CFP->getValueAPF().bitcastToAPInt();
 672         const uint64_t *p = api.getRawData();
 673         Record.push_back((p[1] << 48) | (p[0] >> 16));
 674         Record.push_back(p[0] & 0xffffLL);
 675       } else if (Ty == Type::getFP128Ty(Ty->getContext()) ||
 676                  Ty == Type::getPPC_FP128Ty(Ty->getContext())) {
 677         APInt api = CFP->getValueAPF().bitcastToAPInt();
 678         const uint64_t *p = api.getRawData();
 679         Record.push_back(p[0]);
 680         Record.push_back(p[1]);
 681       } else {
 682         assert (0 && "Unknown FP type!");
 683       }
 684     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 685       // Emit constant strings specially.
 686       unsigned NumOps = C->getNumOperands();
 687       // If this is a null-terminated string, use the denser CSTRING encoding.
 688       if (C->getOperand(NumOps-1)->isNullValue()) {
 689         Code = bitc::CST_CODE_CSTRING;
 690         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 691       } else {
 692         Code = bitc::CST_CODE_STRING;
 693         AbbrevToUse = String8Abbrev;
 694       }
 695       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 696       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 697       for (unsigned i = 0; i != NumOps; ++i) {
 698         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 699         Record.push_back(V);
 700         isCStr7 &= (V & 128) == 0;
 701         if (isCStrChar6)
 702           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 703       }
 704
 705       if (isCStrChar6)
 706         AbbrevToUse = CString6Abbrev;
 707       else if (isCStr7)
 708         AbbrevToUse = CString7Abbrev;
 709     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 710                isa<ConstantVector>(V)) {
 711       Code = bitc::CST_CODE_AGGREGATE;
 712       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 713         Record.push_back(VE.getValueID(C->getOperand(i)));
 714       AbbrevToUse = AggregateAbbrev;
 715     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 716       switch (CE->getOpcode()) {
 717       default:
 718         if (Instruction::isCast(CE->getOpcode())) {
 719           Code = bitc::CST_CODE_CE_CAST;
 720           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 721           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 722           Record.push_back(VE.getValueID(C->getOperand(0)));
 723           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 724         } else {
 725           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 726           Code = bitc::CST_CODE_CE_BINOP;
 727           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 728           Record.push_back(VE.getValueID(C->getOperand(0)));
 729           Record.push_back(VE.getValueID(C->getOperand(1)));
 730           uint64_t Flags = GetOptimizationFlags(CE);
 731           if (Flags != 0)
 732             Record.push_back(Flags);
 733         }
 734         break;
 735       case Instruction::GetElementPtr:
 736         Code = bitc::CST_CODE_CE_GEP;
 737         if (cast<GEPOperator>(C)->isInBounds())
 738           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 739         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 740           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 741           Record.push_back(VE.getValueID(C->getOperand(i)));
 742         }
 743         break;
 744       case Instruction::Select:
 745         Code = bitc::CST_CODE_CE_SELECT;
 746         Record.push_back(VE.getValueID(C->getOperand(0)));
 747         Record.push_back(VE.getValueID(C->getOperand(1)));
 748         Record.push_back(VE.getValueID(C->getOperand(2)));
 749         break;
 750       case Instruction::ExtractElement:
 751         Code = bitc::CST_CODE_CE_EXTRACTELT;
 752         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 753         Record.push_back(VE.getValueID(C->getOperand(0)));
 754         Record.push_back(VE.getValueID(C->getOperand(1)));
 755         break;
 756       case Instruction::InsertElement:
 757         Code = bitc::CST_CODE_CE_INSERTELT;
 758         Record.push_back(VE.getValueID(C->getOperand(0)));
 759         Record.push_back(VE.getValueID(C->getOperand(1)));
 760         Record.push_back(VE.getValueID(C->getOperand(2)));
 761         break;
 762       case Instruction::ShuffleVector:
 763         // If the return type and argument types are the same, this is a
 764         // standard shufflevector instruction.  If the types are different,
 765         // then the shuffle is widening or truncating the input vectors, and
 766         // the argument type must also be encoded.
 767         if (C->getType() == C->getOperand(0)->getType()) {
 768           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 769         } else {
 770           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 771           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 772         }
 773         Record.push_back(VE.getValueID(C->getOperand(0)));
 774         Record.push_back(VE.getValueID(C->getOperand(1)));
 775         Record.push_back(VE.getValueID(C->getOperand(2)));
 776         break;
 777       case Instruction::ICmp:
 778       case Instruction::FCmp:
 779         Code = bitc::CST_CODE_CE_CMP;
 780         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 781         Record.push_back(VE.getValueID(C->getOperand(0)));
 782         Record.push_back(VE.getValueID(C->getOperand(1)));
 783         Record.push_back(CE->getPredicate());
 784         break;
 785       }
 786     } else {
 787       llvm_unreachable("Unknown constant!");
 788     }
 789     Stream.EmitRecord(Code, Record, AbbrevToUse);
 790     Record.clear();
 791   }
 792
 793   Stream.ExitBlock();
 794 }
 795
 796 static void WriteModuleConstants(const ValueEnumerator &VE,
 797                                  BitstreamWriter &Stream) {
 798   const ValueEnumerator::ValueList &Vals = VE.getValues();
 799
 800   // Find the first constant to emit, which is the first non-globalvalue value.
 801   // We know globalvalues have been emitted by WriteModuleInfo.
 802   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 803     if (!isa<GlobalValue>(Vals[i].first)) {
 804       WriteConstants(i, Vals.size(), VE, Stream, true);
 805       return;
 806     }
 807   }
 808 }
 809
 810 /// PushValueAndType - The file has to encode both the value and type id for
 811 /// many values, because we need to know what type to create for forward
 812 /// references.  However, most operands are not forward references, so this type
 813 /// field is not needed.
 814 ///
 815 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 816 /// instruction ID, then it is a forward reference, and it also includes the
 817 /// type ID.
 818 static bool PushValueAndType(const Value *V, unsigned InstID,
 819                              SmallVector<unsigned, 64> &Vals,
 820                              ValueEnumerator &VE) {
 821   unsigned ValID = VE.getValueID(V);
 822   Vals.push_back(ValID);
 823   if (ValID >= InstID) {
 824     Vals.push_back(VE.getTypeID(V->getType()));
 825     return true;
 826   }
 827   return false;
 828 }
 829
 830 /// WriteInstruction - Emit an instruction to the specified stream.
 831 static void WriteInstruction(const Instruction &I, unsigned InstID,
 832                              ValueEnumerator &VE, BitstreamWriter &Stream,
 833                              SmallVector<unsigned, 64> &Vals) {
 834   unsigned Code = 0;
 835   unsigned AbbrevToUse = 0;
 836   switch (I.getOpcode()) {
 837   default:
 838     if (Instruction::isCast(I.getOpcode())) {
 839       Code = bitc::FUNC_CODE_INST_CAST;
 840       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 841         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 842       Vals.push_back(VE.getTypeID(I.getType()));
 843       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 844     } else {
 845       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 846       Code = bitc::FUNC_CODE_INST_BINOP;
 847       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 848         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 849       Vals.push_back(VE.getValueID(I.getOperand(1)));
 850       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 851       uint64_t Flags = GetOptimizationFlags(&I);
 852       if (Flags != 0) {
 853         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 854           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 855         Vals.push_back(Flags);
 856       }
 857     }
 858     break;
 859
 860   case Instruction::GetElementPtr:
 861     Code = bitc::FUNC_CODE_INST_GEP;
 862     if (cast<GEPOperator>(&I)->isInBounds())
 863       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 864     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 865       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 866     break;
 867   case Instruction::ExtractValue: {
 868     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 869     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 870     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 871     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 872       Vals.push_back(*i);
 873     break;
 874   }
 875   case Instruction::InsertValue: {
 876     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 877     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 878     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 879     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 880     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 881       Vals.push_back(*i);
 882     break;
 883   }
 884   case Instruction::Select:
 885     Code = bitc::FUNC_CODE_INST_VSELECT;
 886     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 887     Vals.push_back(VE.getValueID(I.getOperand(2)));
 888     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 889     break;
 890   case Instruction::ExtractElement:
 891     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 892     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 893     Vals.push_back(VE.getValueID(I.getOperand(1)));
 894     break;
 895   case Instruction::InsertElement:
 896     Code = bitc::FUNC_CODE_INST_INSERTELT;
 897     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 898     Vals.push_back(VE.getValueID(I.getOperand(1)));
 899     Vals.push_back(VE.getValueID(I.getOperand(2)));
 900     break;
 901   case Instruction::ShuffleVector:
 902     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 903     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 904     Vals.push_back(VE.getValueID(I.getOperand(1)));
 905     Vals.push_back(VE.getValueID(I.getOperand(2)));
 906     break;
 907   case Instruction::ICmp:
 908   case Instruction::FCmp:
 909     // compare returning Int1Ty or vector of Int1Ty
 910     Code = bitc::FUNC_CODE_INST_CMP2;
 911     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 912     Vals.push_back(VE.getValueID(I.getOperand(1)));
 913     Vals.push_back(cast<CmpInst>(I).getPredicate());
 914     break;
 915
 916   case Instruction::Ret:
 917     {
 918       Code = bitc::FUNC_CODE_INST_RET;
 919       unsigned NumOperands = I.getNumOperands();
 920       if (NumOperands == 0)
 921         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 922       else if (NumOperands == 1) {
 923         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 924           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 925       } else {
 926         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 927           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 928       }
 929     }
 930     break;
 931   case Instruction::Br:
 932     {
 933       Code = bitc::FUNC_CODE_INST_BR;
 934       BranchInst &II(cast<BranchInst>(I));
 935       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 936       if (II.isConditional()) {
 937         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 938         Vals.push_back(VE.getValueID(II.getCondition()));
 939       }
 940     }
 941     break;
 942   case Instruction::Switch:
 943     Code = bitc::FUNC_CODE_INST_SWITCH;
 944     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 945     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 946       Vals.push_back(VE.getValueID(I.getOperand(i)));
 947     break;
 948   case Instruction::Invoke: {
 949     const InvokeInst *II = cast<InvokeInst>(&I);
 950     const Value *Callee(II->getCalledValue());
 951     const PointerType *PTy = cast<PointerType>(Callee->getType());
 952     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 953     Code = bitc::FUNC_CODE_INST_INVOKE;
 954
 955     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 956     Vals.push_back(II->getCallingConv());
 957     Vals.push_back(VE.getValueID(II->getNormalDest()));
 958     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 959     PushValueAndType(Callee, InstID, Vals, VE);
 960
 961     // Emit value #'s for the fixed parameters.
 962     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 963       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 964
 965     // Emit type/value pairs for varargs params.
 966     if (FTy->isVarArg()) {
 967       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 968            i != e; ++i)
 969         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 970     }
 971     break;
 972   }
 973   case Instruction::Unwind:
 974     Code = bitc::FUNC_CODE_INST_UNWIND;
 975     break;
 976   case Instruction::Unreachable:
 977     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 978     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 979     break;
 980
 981   case Instruction::PHI:
 982     Code = bitc::FUNC_CODE_INST_PHI;
 983     Vals.push_back(VE.getTypeID(I.getType()));
 984     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 985       Vals.push_back(VE.getValueID(I.getOperand(i)));
 986     break;
 987
 988   case Instruction::Malloc:
 989     Code = bitc::FUNC_CODE_INST_MALLOC;
 990     Vals.push_back(VE.getTypeID(I.getType()));
 991     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 992     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 993     break;
 994
 995   case Instruction::Free:
 996     Code = bitc::FUNC_CODE_INST_FREE;
 997     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 998     break;
 999
1000   case Instruction::Alloca:
1001     Code = bitc::FUNC_CODE_INST_ALLOCA;
1002     Vals.push_back(VE.getTypeID(I.getType()));
1003     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1004     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1005     break;
1006
1007   case Instruction::Load:
1008     Code = bitc::FUNC_CODE_INST_LOAD;
1009     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1010       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1011
1012     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1013     Vals.push_back(cast<LoadInst>(I).isVolatile());
1014     break;
1015   case Instruction::Store:
1016     Code = bitc::FUNC_CODE_INST_STORE2;
1017     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1018     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1019     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1020     Vals.push_back(cast<StoreInst>(I).isVolatile());
1021     break;
1022   case Instruction::Call: {
1023     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1024     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1025
1026     Code = bitc::FUNC_CODE_INST_CALL;
1027
1028     const CallInst *CI = cast<CallInst>(&I);
1029     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1030     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1031     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1032
1033     // Emit value #'s for the fixed parameters.
1034     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1035       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1036
1037     // Emit type/value pairs for varargs params.
1038     if (FTy->isVarArg()) {
1039       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1040       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1041            i != e; ++i)
1042         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1043     }
1044     break;
1045   }
1046   case Instruction::VAArg:
1047     Code = bitc::FUNC_CODE_INST_VAARG;
1048     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1049     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1050     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1051     break;
1052   }
1053
1054   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1055   Vals.clear();
1056 }
1057
1058 // Emit names for globals/functions etc.
1059 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1060                                   const ValueEnumerator &VE,
1061                                   BitstreamWriter &Stream) {
1062   if (VST.empty()) return;
1063   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1064
1065   // FIXME: Set up the abbrev, we know how many values there are!
1066   // FIXME: We know if the type names can use 7-bit ascii.
1067   SmallVector<unsigned, 64> NameVals;
1068
1069   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1070        SI != SE; ++SI) {
1071
1072     const ValueName &Name = *SI;
1073
1074     // Figure out the encoding to use for the name.
1075     bool is7Bit = true;
1076     bool isChar6 = true;
1077     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1078          C != E; ++C) {
1079       if (isChar6)
1080         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1081       if ((unsigned char)*C & 128) {
1082         is7Bit = false;
1083         break;  // don't bother scanning the rest.
1084       }
1085     }
1086
1087     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1088
1089     // VST_ENTRY:   [valueid, namechar x N]
1090     // VST_BBENTRY: [bbid, namechar x N]
1091     unsigned Code;
1092     if (isa<BasicBlock>(SI->getValue())) {
1093       Code = bitc::VST_CODE_BBENTRY;
1094       if (isChar6)
1095         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1096     } else {
1097       Code = bitc::VST_CODE_ENTRY;
1098       if (isChar6)
1099         AbbrevToUse = VST_ENTRY_6_ABBREV;
1100       else if (is7Bit)
1101         AbbrevToUse = VST_ENTRY_7_ABBREV;
1102     }
1103
1104     NameVals.push_back(VE.getValueID(SI->getValue()));
1105     for (const char *P = Name.getKeyData(),
1106          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1107       NameVals.push_back((unsigned char)*P);
1108
1109     // Emit the finished record.
1110     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1111     NameVals.clear();
1112   }
1113   Stream.ExitBlock();
1114 }
1115
1116 /// WriteFunction - Emit a function body to the module stream.
1117 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1118                           BitstreamWriter &Stream) {
1119   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1120   VE.incorporateFunction(F);
1121
1122   SmallVector<unsigned, 64> Vals;
1123
1124   // Emit the number of basic blocks, so the reader can create them ahead of
1125   // time.
1126   Vals.push_back(VE.getBasicBlocks().size());
1127   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1128   Vals.clear();
1129
1130   // If there are function-local constants, emit them now.
1131   unsigned CstStart, CstEnd;
1132   VE.getFunctionConstantRange(CstStart, CstEnd);
1133   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1134
1135   // Keep a running idea of what the instruction ID is.
1136   unsigned InstID = CstEnd;
1137
1138   // Finally, emit all the instructions, in order.
1139   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1140     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1141          I != E; ++I) {
1142       WriteInstruction(*I, InstID, VE, Stream, Vals);
1143       if (I->getType() != Type::getVoidTy(F.getContext()))
1144         ++InstID;
1145     }
1146
1147   // Emit names for all the instructions etc.
1148   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1149
1150   VE.purgeFunction();
1151   Stream.ExitBlock();
1152 }
1153
1154 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1155 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1156                                  const ValueEnumerator &VE,
1157                                  BitstreamWriter &Stream) {
1158   if (TST.empty()) return;
1159
1160   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1161
1162   // 7-bit fixed width VST_CODE_ENTRY strings.
1163   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1164   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1166                             Log2_32_Ceil(VE.getTypes().size()+1)));
1167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1169   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1170
1171   SmallVector<unsigned, 64> NameVals;
1172
1173   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1174        TI != TE; ++TI) {
1175     // TST_ENTRY: [typeid, namechar x N]
1176     NameVals.push_back(VE.getTypeID(TI->second));
1177
1178     const std::string &Str = TI->first;
1179     bool is7Bit = true;
1180     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1181       NameVals.push_back((unsigned char)Str[i]);
1182       if (Str[i] & 128)
1183         is7Bit = false;
1184     }
1185
1186     // Emit the finished record.
1187     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1188     NameVals.clear();
1189   }
1190
1191   Stream.ExitBlock();
1192 }
1193
1194 // Emit blockinfo, which defines the standard abbreviations etc.
1195 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1196   // We only want to emit block info records for blocks that have multiple
1197   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1198   // blocks can defined their abbrevs inline.
1199   Stream.EnterBlockInfoBlock(2);
1200
1201   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1202     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1203     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1206     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1207     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1208                                    Abbv) != VST_ENTRY_8_ABBREV)
1209       llvm_unreachable("Unexpected abbrev ordering!");
1210   }
1211
1212   { // 7-bit fixed width VST_ENTRY strings.
1213     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1214     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1218     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1219                                    Abbv) != VST_ENTRY_7_ABBREV)
1220       llvm_unreachable("Unexpected abbrev ordering!");
1221   }
1222   { // 6-bit char6 VST_ENTRY strings.
1223     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1224     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1228     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1229                                    Abbv) != VST_ENTRY_6_ABBREV)
1230       llvm_unreachable("Unexpected abbrev ordering!");
1231   }
1232   { // 6-bit char6 VST_BBENTRY strings.
1233     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1234     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1238     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1239                                    Abbv) != VST_BBENTRY_6_ABBREV)
1240       llvm_unreachable("Unexpected abbrev ordering!");
1241   }
1242
1243
1244
1245   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1246     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1247     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1249                               Log2_32_Ceil(VE.getTypes().size()+1)));
1250     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1251                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1252       llvm_unreachable("Unexpected abbrev ordering!");
1253   }
1254
1255   { // INTEGER abbrev for CONSTANTS_BLOCK.
1256     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1257     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1259     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1260                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1261       llvm_unreachable("Unexpected abbrev ordering!");
1262   }
1263
1264   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1265     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1266     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1269                               Log2_32_Ceil(VE.getTypes().size()+1)));
1270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1271
1272     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1273                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1274       llvm_unreachable("Unexpected abbrev ordering!");
1275   }
1276   { // NULL abbrev for CONSTANTS_BLOCK.
1277     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1278     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1279     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1280                                    Abbv) != CONSTANTS_NULL_Abbrev)
1281       llvm_unreachable("Unexpected abbrev ordering!");
1282   }
1283
1284   // FIXME: This should only use space for first class types!
1285
1286   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1287     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1288     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1292     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1293                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1294       llvm_unreachable("Unexpected abbrev ordering!");
1295   }
1296   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1297     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1298     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1302     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1303                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1304       llvm_unreachable("Unexpected abbrev ordering!");
1305   }
1306   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1307     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1308     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1313     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1314                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1315       llvm_unreachable("Unexpected abbrev ordering!");
1316   }
1317   { // INST_CAST abbrev for FUNCTION_BLOCK.
1318     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1319     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1322                               Log2_32_Ceil(VE.getTypes().size()+1)));
1323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1324     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1325                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1326       llvm_unreachable("Unexpected abbrev ordering!");
1327   }
1328
1329   { // INST_RET abbrev for FUNCTION_BLOCK.
1330     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1331     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1332     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1333                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1334       llvm_unreachable("Unexpected abbrev ordering!");
1335   }
1336   { // INST_RET abbrev for FUNCTION_BLOCK.
1337     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1338     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1339     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1340     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1341                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1342       llvm_unreachable("Unexpected abbrev ordering!");
1343   }
1344   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1345     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1346     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1347     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1348                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1349       llvm_unreachable("Unexpected abbrev ordering!");
1350   }
1351
1352   Stream.ExitBlock();
1353 }
1354
1355
1356 /// WriteModule - Emit the specified module to the bitstream.
1357 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1358   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1359
1360   // Emit the version number if it is non-zero.
1361   if (CurVersion) {
1362     SmallVector<unsigned, 1> Vals;
1363     Vals.push_back(CurVersion);
1364     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1365   }
1366
1367   // Analyze the module, enumerating globals, functions, etc.
1368   ValueEnumerator VE(M);
1369
1370   // Emit blockinfo, which defines the standard abbreviations etc.
1371   WriteBlockInfo(VE, Stream);
1372
1373   // Emit information about parameter attributes.
1374   WriteAttributeTable(VE, Stream);
1375
1376   // Emit information describing all of the types in the module.
1377   WriteTypeTable(VE, Stream);
1378
1379   // Emit top-level description of module, including target triple, inline asm,
1380   // descriptors for global variables, and function prototype info.
1381   WriteModuleInfo(M, VE, Stream);
1382
1383   // Emit constants.
1384   WriteModuleConstants(VE, Stream);
1385
1386   // Emit metadata.
1387   WriteModuleMetadata(VE, Stream);
1388
1389   // Emit function bodies.
1390   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1391     if (!I->isDeclaration())
1392       WriteFunction(*I, VE, Stream);
1393
1394   // Emit the type symbol table information.
1395   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1396
1397   // Emit names for globals/functions etc.
1398   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1399
1400   Stream.ExitBlock();
1401 }
1402
1403 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1404 /// header and trailer to make it compatible with the system archiver.  To do
1405 /// this we emit the following header, and then emit a trailer that pads the
1406 /// file out to be a multiple of 16 bytes.
1407 ///
1408 /// struct bc_header {
1409 ///   uint32_t Magic;         // 0x0B17C0DE
1410 ///   uint32_t Version;       // Version, currently always 0.
1411 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1412 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1413 ///   uint32_t CPUType;       // CPU specifier.
1414 ///   ... potentially more later ...
1415 /// };
1416 enum {
1417   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1418   DarwinBCHeaderSize = 5*4
1419 };
1420
1421 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1422                                const std::string &TT) {
1423   unsigned CPUType = ~0U;
1424
1425   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1426   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1427   // specific constants here because they are implicitly part of the Darwin ABI.
1428   enum {
1429     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1430     DARWIN_CPU_TYPE_X86        = 7,
1431     DARWIN_CPU_TYPE_POWERPC    = 18
1432   };
1433
1434   if (TT.find("x86_64-") == 0)
1435     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1436   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1437            TT[4] == '-' && TT[1] - '3' < 6)
1438     CPUType = DARWIN_CPU_TYPE_X86;
1439   else if (TT.find("powerpc-") == 0)
1440     CPUType = DARWIN_CPU_TYPE_POWERPC;
1441   else if (TT.find("powerpc64-") == 0)
1442     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1443
1444   // Traditional Bitcode starts after header.
1445   unsigned BCOffset = DarwinBCHeaderSize;
1446
1447   Stream.Emit(0x0B17C0DE, 32);
1448   Stream.Emit(0         , 32);  // Version.
1449   Stream.Emit(BCOffset  , 32);
1450   Stream.Emit(0         , 32);  // Filled in later.
1451   Stream.Emit(CPUType   , 32);
1452 }
1453
1454 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1455 /// finalize the header.
1456 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1457   // Update the size field in the header.
1458   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1459
1460   // If the file is not a multiple of 16 bytes, insert dummy padding.
1461   while (BufferSize & 15) {
1462     Stream.Emit(0, 8);
1463     ++BufferSize;
1464   }
1465 }
1466
1467
1468 /// WriteBitcodeToFile - Write the specified module to the specified output
1469 /// stream.
1470 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1471   std::vector<unsigned char> Buffer;
1472   BitstreamWriter Stream(Buffer);
1473
1474   Buffer.reserve(256*1024);
1475
1476   WriteBitcodeToStream( M, Stream );
1477
1478   // If writing to stdout, set binary mode.
1479   if (&llvm::outs() == &Out)
1480     sys::Program::ChangeStdoutToBinary();
1481
1482   // Write the generated bitstream to "Out".
1483   Out.write((char*)&Buffer.front(), Buffer.size());
1484
1485   // Make sure it hits disk now.
1486   Out.flush();
1487 }
1488
1489 /// WriteBitcodeToStream - Write the specified module to the specified output
1490 /// stream.
1491 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1492   // If this is darwin, emit a file header and trailer if needed.
1493   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1494   if (isDarwin)
1495     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1496
1497   // Emit the file header.
1498   Stream.Emit((unsigned)'B', 8);
1499   Stream.Emit((unsigned)'C', 8);
1500   Stream.Emit(0x0, 4);
1501   Stream.Emit(0xC, 4);
1502   Stream.Emit(0xE, 4);
1503   Stream.Emit(0xD, 4);
1504
1505   // Emit the module.
1506   WriteModule(M, Stream);
1507
1508   if (isDarwin)
1509     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1510 }