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/Streams.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include "llvm/System/Program.h"
  32 using namespace llvm;
  33
  34 /// These are manifest constants used by the bitcode writer. They do not need to
  35 /// be kept in sync with the reader, but need to be consistent within this file.
  36 enum {
  37   CurVersion = 0,
  38
  39   // VALUE_SYMTAB_BLOCK abbrev id's.
  40   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  41   VST_ENTRY_7_ABBREV,
  42   VST_ENTRY_6_ABBREV,
  43   VST_BBENTRY_6_ABBREV,
  44
  45   // CONSTANTS_BLOCK abbrev id's.
  46   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  47   CONSTANTS_INTEGER_ABBREV,
  48   CONSTANTS_CE_CAST_Abbrev,
  49   CONSTANTS_NULL_Abbrev,
  50
  51   // FUNCTION_BLOCK abbrev id's.
  52   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  53   FUNCTION_INST_BINOP_ABBREV,
  54   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  55   FUNCTION_INST_CAST_ABBREV,
  56   FUNCTION_INST_RET_VOID_ABBREV,
  57   FUNCTION_INST_RET_VAL_ABBREV,
  58   FUNCTION_INST_UNREACHABLE_ABBREV
  59 };
  60
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   }
  78 }
  79
  80 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  81   switch (Opcode) {
  82   default: llvm_unreachable("Unknown binary instruction!");
  83   case Instruction::Add:
  84   case Instruction::FAdd: return bitc::BINOP_ADD;
  85   case Instruction::Sub:
  86   case Instruction::FSub: return bitc::BINOP_SUB;
  87   case Instruction::Mul:
  88   case Instruction::FMul: return bitc::BINOP_MUL;
  89   case Instruction::UDiv: return bitc::BINOP_UDIV;
  90   case Instruction::FDiv:
  91   case Instruction::SDiv: return bitc::BINOP_SDIV;
  92   case Instruction::URem: return bitc::BINOP_UREM;
  93   case Instruction::FRem:
  94   case Instruction::SRem: return bitc::BINOP_SREM;
  95   case Instruction::Shl:  return bitc::BINOP_SHL;
  96   case Instruction::LShr: return bitc::BINOP_LSHR;
  97   case Instruction::AShr: return bitc::BINOP_ASHR;
  98   case Instruction::And:  return bitc::BINOP_AND;
  99   case Instruction::Or:   return bitc::BINOP_OR;
 100   case Instruction::Xor:  return bitc::BINOP_XOR;
 101   }
 102 }
 103
 104
 105
 106 static void WriteStringRecord(unsigned Code, const std::string &Str,
 107                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 108   SmallVector<unsigned, 64> Vals;
 109
 110   // Code: [strchar x N]
 111   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 112     Vals.push_back(Str[i]);
 113
 114   // Emit the finished record.
 115   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 116 }
 117
 118 // Emit information about parameter attributes.
 119 static void WriteAttributeTable(const ValueEnumerator &VE,
 120                                 BitstreamWriter &Stream) {
 121   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 122   if (Attrs.empty()) return;
 123
 124   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 125
 126   SmallVector<uint64_t, 64> Record;
 127   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 128     const AttrListPtr &A = Attrs[i];
 129     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 130       const AttributeWithIndex &PAWI = A.getSlot(i);
 131       Record.push_back(PAWI.Index);
 132
 133       // FIXME: remove in LLVM 3.0
 134       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 135       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 136       // 11 bits.
 137       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 138       if (PAWI.Attrs & Attribute::Alignment)
 139         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 140       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 141
 142       Record.push_back(FauxAttr);
 143     }
 144
 145     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 146     Record.clear();
 147   }
 148
 149   Stream.ExitBlock();
 150 }
 151
 152 /// WriteTypeTable - Write out the type table for a module.
 153 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 154   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 155
 156   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 157   SmallVector<uint64_t, 64> TypeVals;
 158
 159   // Abbrev for TYPE_CODE_POINTER.
 160   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 161   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 163                             Log2_32_Ceil(VE.getTypes().size()+1)));
 164   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 165   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 166
 167   // Abbrev for TYPE_CODE_FUNCTION.
 168   Abbv = new BitCodeAbbrev();
 169   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 171   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 174                             Log2_32_Ceil(VE.getTypes().size()+1)));
 175   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 176
 177   // Abbrev for TYPE_CODE_STRUCT.
 178   Abbv = new BitCodeAbbrev();
 179   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 183                             Log2_32_Ceil(VE.getTypes().size()+1)));
 184   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 185
 186   // Abbrev for TYPE_CODE_ARRAY.
 187   Abbv = new BitCodeAbbrev();
 188   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 191                             Log2_32_Ceil(VE.getTypes().size()+1)));
 192   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 193
 194   // Emit an entry count so the reader can reserve space.
 195   TypeVals.push_back(TypeList.size());
 196   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 197   TypeVals.clear();
 198
 199   // Loop over all of the types, emitting each in turn.
 200   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 201     const Type *T = TypeList[i].first;
 202     int AbbrevToUse = 0;
 203     unsigned Code = 0;
 204
 205     switch (T->getTypeID()) {
 206     default: llvm_unreachable("Unknown type!");
 207     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 208     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 209     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 210     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 211     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 212     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 213     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 214     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 215     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 216     case Type::IntegerTyID:
 217       // INTEGER: [width]
 218       Code = bitc::TYPE_CODE_INTEGER;
 219       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 220       break;
 221     case Type::PointerTyID: {
 222       const PointerType *PTy = cast<PointerType>(T);
 223       // POINTER: [pointee type, address space]
 224       Code = bitc::TYPE_CODE_POINTER;
 225       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 226       unsigned AddressSpace = PTy->getAddressSpace();
 227       TypeVals.push_back(AddressSpace);
 228       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 229       break;
 230     }
 231     case Type::FunctionTyID: {
 232       const FunctionType *FT = cast<FunctionType>(T);
 233       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 234       Code = bitc::TYPE_CODE_FUNCTION;
 235       TypeVals.push_back(FT->isVarArg());
 236       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 237       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 238       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 239         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 240       AbbrevToUse = FunctionAbbrev;
 241       break;
 242     }
 243     case Type::StructTyID: {
 244       const StructType *ST = cast<StructType>(T);
 245       // STRUCT: [ispacked, eltty x N]
 246       Code = bitc::TYPE_CODE_STRUCT;
 247       TypeVals.push_back(ST->isPacked());
 248       // Output all of the element types.
 249       for (StructType::element_iterator I = ST->element_begin(),
 250            E = ST->element_end(); I != E; ++I)
 251         TypeVals.push_back(VE.getTypeID(*I));
 252       AbbrevToUse = StructAbbrev;
 253       break;
 254     }
 255     case Type::ArrayTyID: {
 256       const ArrayType *AT = cast<ArrayType>(T);
 257       // ARRAY: [numelts, eltty]
 258       Code = bitc::TYPE_CODE_ARRAY;
 259       TypeVals.push_back(AT->getNumElements());
 260       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 261       AbbrevToUse = ArrayAbbrev;
 262       break;
 263     }
 264     case Type::VectorTyID: {
 265       const VectorType *VT = cast<VectorType>(T);
 266       // VECTOR [numelts, eltty]
 267       Code = bitc::TYPE_CODE_VECTOR;
 268       TypeVals.push_back(VT->getNumElements());
 269       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 270       break;
 271     }
 272     }
 273
 274     // Emit the finished record.
 275     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 276     TypeVals.clear();
 277   }
 278
 279   Stream.ExitBlock();
 280 }
 281
 282 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 283   switch (GV->getLinkage()) {
 284   default: llvm_unreachable("Invalid linkage!");
 285   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 286   case GlobalValue::ExternalLinkage:            return 0;
 287   case GlobalValue::WeakAnyLinkage:             return 1;
 288   case GlobalValue::AppendingLinkage:           return 2;
 289   case GlobalValue::InternalLinkage:            return 3;
 290   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 291   case GlobalValue::DLLImportLinkage:           return 5;
 292   case GlobalValue::DLLExportLinkage:           return 6;
 293   case GlobalValue::ExternalWeakLinkage:        return 7;
 294   case GlobalValue::CommonLinkage:              return 8;
 295   case GlobalValue::PrivateLinkage:             return 9;
 296   case GlobalValue::WeakODRLinkage:             return 10;
 297   case GlobalValue::LinkOnceODRLinkage:         return 11;
 298   case GlobalValue::AvailableExternallyLinkage: return 12;
 299   case GlobalValue::LinkerPrivateLinkage:       return 13;
 300   }
 301 }
 302
 303 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 304   switch (GV->getVisibility()) {
 305   default: llvm_unreachable("Invalid visibility!");
 306   case GlobalValue::DefaultVisibility:   return 0;
 307   case GlobalValue::HiddenVisibility:    return 1;
 308   case GlobalValue::ProtectedVisibility: return 2;
 309   }
 310 }
 311
 312 // Emit top-level description of module, including target triple, inline asm,
 313 // descriptors for global variables, and function prototype info.
 314 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 315                             BitstreamWriter &Stream) {
 316   // Emit the list of dependent libraries for the Module.
 317   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 318     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 319
 320   // Emit various pieces of data attached to a module.
 321   if (!M->getTargetTriple().empty())
 322     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 323                       0/*TODO*/, Stream);
 324   if (!M->getDataLayout().empty())
 325     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 326                       0/*TODO*/, Stream);
 327   if (!M->getModuleInlineAsm().empty())
 328     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 329                       0/*TODO*/, Stream);
 330
 331   // Emit information about sections and GC, computing how many there are. Also
 332   // compute the maximum alignment value.
 333   std::map<std::string, unsigned> SectionMap;
 334   std::map<std::string, unsigned> GCMap;
 335   unsigned MaxAlignment = 0;
 336   unsigned MaxGlobalType = 0;
 337   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 338        GV != E; ++GV) {
 339     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 340     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 341
 342     if (!GV->hasSection()) continue;
 343     // Give section names unique ID's.
 344     unsigned &Entry = SectionMap[GV->getSection()];
 345     if (Entry != 0) continue;
 346     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 347                       0/*TODO*/, Stream);
 348     Entry = SectionMap.size();
 349   }
 350   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 351     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 352     if (F->hasSection()) {
 353       // Give section names unique ID's.
 354       unsigned &Entry = SectionMap[F->getSection()];
 355       if (!Entry) {
 356         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 357                           0/*TODO*/, Stream);
 358         Entry = SectionMap.size();
 359       }
 360     }
 361     if (F->hasGC()) {
 362       // Same for GC names.
 363       unsigned &Entry = GCMap[F->getGC()];
 364       if (!Entry) {
 365         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 366                           0/*TODO*/, Stream);
 367         Entry = GCMap.size();
 368       }
 369     }
 370   }
 371
 372   // Emit abbrev for globals, now that we know # sections and max alignment.
 373   unsigned SimpleGVarAbbrev = 0;
 374   if (!M->global_empty()) {
 375     // Add an abbrev for common globals with no visibility or thread localness.
 376     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 377     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 379                               Log2_32_Ceil(MaxGlobalType+1)));
 380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 383     if (MaxAlignment == 0)                                      // Alignment.
 384       Abbv->Add(BitCodeAbbrevOp(0));
 385     else {
 386       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 387       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 388                                Log2_32_Ceil(MaxEncAlignment+1)));
 389     }
 390     if (SectionMap.empty())                                    // Section.
 391       Abbv->Add(BitCodeAbbrevOp(0));
 392     else
 393       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 394                                Log2_32_Ceil(SectionMap.size()+1)));
 395     // Don't bother emitting vis + thread local.
 396     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 397   }
 398
 399   // Emit the global variable information.
 400   SmallVector<unsigned, 64> Vals;
 401   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 402        GV != E; ++GV) {
 403     unsigned AbbrevToUse = 0;
 404
 405     // GLOBALVAR: [type, isconst, initid,
 406     //             linkage, alignment, section, visibility, threadlocal]
 407     Vals.push_back(VE.getTypeID(GV->getType()));
 408     Vals.push_back(GV->isConstant());
 409     Vals.push_back(GV->isDeclaration() ? 0 :
 410                    (VE.getValueID(GV->getInitializer()) + 1));
 411     Vals.push_back(getEncodedLinkage(GV));
 412     Vals.push_back(Log2_32(GV->getAlignment())+1);
 413     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 414     if (GV->isThreadLocal() ||
 415         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 416       Vals.push_back(getEncodedVisibility(GV));
 417       Vals.push_back(GV->isThreadLocal());
 418     } else {
 419       AbbrevToUse = SimpleGVarAbbrev;
 420     }
 421
 422     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 423     Vals.clear();
 424   }
 425
 426   // Emit the function proto information.
 427   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 428     // FUNCTION:  [type, callingconv, isproto, paramattr,
 429     //             linkage, alignment, section, visibility, gc]
 430     Vals.push_back(VE.getTypeID(F->getType()));
 431     Vals.push_back(F->getCallingConv());
 432     Vals.push_back(F->isDeclaration());
 433     Vals.push_back(getEncodedLinkage(F));
 434     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 435     Vals.push_back(Log2_32(F->getAlignment())+1);
 436     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 437     Vals.push_back(getEncodedVisibility(F));
 438     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 439
 440     unsigned AbbrevToUse = 0;
 441     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 442     Vals.clear();
 443   }
 444
 445
 446   // Emit the alias information.
 447   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 448        AI != E; ++AI) {
 449     Vals.push_back(VE.getTypeID(AI->getType()));
 450     Vals.push_back(VE.getValueID(AI->getAliasee()));
 451     Vals.push_back(getEncodedLinkage(AI));
 452     Vals.push_back(getEncodedVisibility(AI));
 453     unsigned AbbrevToUse = 0;
 454     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 455     Vals.clear();
 456   }
 457 }
 458
 459 static uint64_t GetOptimizationFlags(const Value *V) {
 460   uint64_t Flags = 0;
 461
 462   if (const OverflowingBinaryOperator *OBO =
 463         dyn_cast<OverflowingBinaryOperator>(V)) {
 464     if (OBO->hasNoSignedOverflow())
 465       Flags |= 1 << bitc::OBO_NO_SIGNED_OVERFLOW;
 466     if (OBO->hasNoUnsignedOverflow())
 467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_OVERFLOW;
 468   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 469     if (Div->isExact())
 470       Flags |= 1 << bitc::SDIV_EXACT;
 471   }
 472
 473   return Flags;
 474 }
 475
 476 static void WriteMDNode(const MDNode *N,
 477                         const ValueEnumerator &VE,
 478                         BitstreamWriter &Stream,
 479                         SmallVector<uint64_t, 64> &Record) {
 480   for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 481     if (N->getElement(i)) {
 482       Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 483       Record.push_back(VE.getValueID(N->getElement(i)));
 484     } else {
 485       Record.push_back(VE.getTypeID(Type::VoidTy));
 486       Record.push_back(0);
 487     }
 488   }
 489   Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
 490   Record.clear();
 491 }
 492
 493 static void WriteModuleMetadata(const ValueEnumerator &VE,
 494                                 BitstreamWriter &Stream) {
 495   const ValueEnumerator::ValueList &Vals = VE.getValues();
 496   bool StartedMetadataBlock = false;
 497   unsigned MDSAbbrev = 0;
 498   SmallVector<uint64_t, 64> Record;
 499   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 500
 501     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 502       if (!StartedMetadataBlock) {
 503         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 504         StartedMetadataBlock = true;
 505       }
 506       WriteMDNode(N, VE, Stream, Record);
 507     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 508       if (!StartedMetadataBlock)  {
 509         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 510
 511         // Abbrev for METADATA_STRING.
 512         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 513         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 514         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 515         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 516         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 517         StartedMetadataBlock = true;
 518       }
 519
 520       // Code: [strchar x N]
 521       const char *StrBegin = MDS->begin();
 522       for (unsigned i = 0, e = MDS->length(); i != e; ++i)
 523         Record.push_back(StrBegin[i]);
 524
 525       // Emit the finished record.
 526       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 527       Record.clear();
 528     }
 529   }
 530
 531   if (StartedMetadataBlock)
 532     Stream.ExitBlock();
 533 }
 534
 535 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 536                            const ValueEnumerator &VE,
 537                            BitstreamWriter &Stream, bool isGlobal) {
 538   if (FirstVal == LastVal) return;
 539
 540   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 541
 542   unsigned AggregateAbbrev = 0;
 543   unsigned String8Abbrev = 0;
 544   unsigned CString7Abbrev = 0;
 545   unsigned CString6Abbrev = 0;
 546   // If this is a constant pool for the module, emit module-specific abbrevs.
 547   if (isGlobal) {
 548     // Abbrev for CST_CODE_AGGREGATE.
 549     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 550     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 552     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 553     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 554
 555     // Abbrev for CST_CODE_STRING.
 556     Abbv = new BitCodeAbbrev();
 557     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 560     String8Abbrev = Stream.EmitAbbrev(Abbv);
 561     // Abbrev for CST_CODE_CSTRING.
 562     Abbv = new BitCodeAbbrev();
 563     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 565     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 566     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 567     // Abbrev for CST_CODE_CSTRING.
 568     Abbv = new BitCodeAbbrev();
 569     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 572     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 573   }
 574
 575   SmallVector<uint64_t, 64> Record;
 576
 577   const ValueEnumerator::ValueList &Vals = VE.getValues();
 578   const Type *LastTy = 0;
 579   for (unsigned i = FirstVal; i != LastVal; ++i) {
 580     const Value *V = Vals[i].first;
 581     if (isa<MDString>(V) || isa<MDNode>(V))
 582       continue;
 583     // If we need to switch types, do so now.
 584     if (V->getType() != LastTy) {
 585       LastTy = V->getType();
 586       Record.push_back(VE.getTypeID(LastTy));
 587       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 588                         CONSTANTS_SETTYPE_ABBREV);
 589       Record.clear();
 590     }
 591
 592     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 593       Record.push_back(unsigned(IA->hasSideEffects()));
 594
 595       // Add the asm string.
 596       const std::string &AsmStr = IA->getAsmString();
 597       Record.push_back(AsmStr.size());
 598       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 599         Record.push_back(AsmStr[i]);
 600
 601       // Add the constraint string.
 602       const std::string &ConstraintStr = IA->getConstraintString();
 603       Record.push_back(ConstraintStr.size());
 604       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 605         Record.push_back(ConstraintStr[i]);
 606       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 607       Record.clear();
 608       continue;
 609     }
 610     const Constant *C = cast<Constant>(V);
 611     unsigned Code = -1U;
 612     unsigned AbbrevToUse = 0;
 613     if (C->isNullValue()) {
 614       Code = bitc::CST_CODE_NULL;
 615     } else if (isa<UndefValue>(C)) {
 616       Code = bitc::CST_CODE_UNDEF;
 617     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 618       if (IV->getBitWidth() <= 64) {
 619         int64_t V = IV->getSExtValue();
 620         if (V >= 0)
 621           Record.push_back(V << 1);
 622         else
 623           Record.push_back((-V << 1) | 1);
 624         Code = bitc::CST_CODE_INTEGER;
 625         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 626       } else {                             // Wide integers, > 64 bits in size.
 627         // We have an arbitrary precision integer value to write whose
 628         // bit width is > 64. However, in canonical unsigned integer
 629         // format it is likely that the high bits are going to be zero.
 630         // So, we only write the number of active words.
 631         unsigned NWords = IV->getValue().getActiveWords();
 632         const uint64_t *RawWords = IV->getValue().getRawData();
 633         for (unsigned i = 0; i != NWords; ++i) {
 634           int64_t V = RawWords[i];
 635           if (V >= 0)
 636             Record.push_back(V << 1);
 637           else
 638             Record.push_back((-V << 1) | 1);
 639         }
 640         Code = bitc::CST_CODE_WIDE_INTEGER;
 641       }
 642     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 643       Code = bitc::CST_CODE_FLOAT;
 644       const Type *Ty = CFP->getType();
 645       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 646         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 647       } else if (Ty == Type::X86_FP80Ty) {
 648         // api needed to prevent premature destruction
 649         // bits are not in the same order as a normal i80 APInt, compensate.
 650         APInt api = CFP->getValueAPF().bitcastToAPInt();
 651         const uint64_t *p = api.getRawData();
 652         Record.push_back((p[1] << 48) | (p[0] >> 16));
 653         Record.push_back(p[0] & 0xffffLL);
 654       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 655         APInt api = CFP->getValueAPF().bitcastToAPInt();
 656         const uint64_t *p = api.getRawData();
 657         Record.push_back(p[0]);
 658         Record.push_back(p[1]);
 659       } else {
 660         assert (0 && "Unknown FP type!");
 661       }
 662     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 663       // Emit constant strings specially.
 664       unsigned NumOps = C->getNumOperands();
 665       // If this is a null-terminated string, use the denser CSTRING encoding.
 666       if (C->getOperand(NumOps-1)->isNullValue()) {
 667         Code = bitc::CST_CODE_CSTRING;
 668         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 669       } else {
 670         Code = bitc::CST_CODE_STRING;
 671         AbbrevToUse = String8Abbrev;
 672       }
 673       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 674       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 675       for (unsigned i = 0; i != NumOps; ++i) {
 676         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 677         Record.push_back(V);
 678         isCStr7 &= (V & 128) == 0;
 679         if (isCStrChar6)
 680           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 681       }
 682
 683       if (isCStrChar6)
 684         AbbrevToUse = CString6Abbrev;
 685       else if (isCStr7)
 686         AbbrevToUse = CString7Abbrev;
 687     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 688                isa<ConstantVector>(V)) {
 689       Code = bitc::CST_CODE_AGGREGATE;
 690       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 691         Record.push_back(VE.getValueID(C->getOperand(i)));
 692       AbbrevToUse = AggregateAbbrev;
 693     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 694       switch (CE->getOpcode()) {
 695       default:
 696         if (Instruction::isCast(CE->getOpcode())) {
 697           Code = bitc::CST_CODE_CE_CAST;
 698           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 699           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 700           Record.push_back(VE.getValueID(C->getOperand(0)));
 701           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 702         } else {
 703           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 704           Code = bitc::CST_CODE_CE_BINOP;
 705           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 706           Record.push_back(VE.getValueID(C->getOperand(0)));
 707           Record.push_back(VE.getValueID(C->getOperand(1)));
 708           uint64_t Flags = GetOptimizationFlags(CE);
 709           if (Flags != 0)
 710             Record.push_back(Flags);
 711         }
 712         break;
 713       case Instruction::GetElementPtr:
 714         Code = bitc::CST_CODE_CE_GEP;
 715         if (cast<GEPOperator>(C)->isInBounds())
 716           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 717         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 718           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 719           Record.push_back(VE.getValueID(C->getOperand(i)));
 720         }
 721         break;
 722       case Instruction::Select:
 723         Code = bitc::CST_CODE_CE_SELECT;
 724         Record.push_back(VE.getValueID(C->getOperand(0)));
 725         Record.push_back(VE.getValueID(C->getOperand(1)));
 726         Record.push_back(VE.getValueID(C->getOperand(2)));
 727         break;
 728       case Instruction::ExtractElement:
 729         Code = bitc::CST_CODE_CE_EXTRACTELT;
 730         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 731         Record.push_back(VE.getValueID(C->getOperand(0)));
 732         Record.push_back(VE.getValueID(C->getOperand(1)));
 733         break;
 734       case Instruction::InsertElement:
 735         Code = bitc::CST_CODE_CE_INSERTELT;
 736         Record.push_back(VE.getValueID(C->getOperand(0)));
 737         Record.push_back(VE.getValueID(C->getOperand(1)));
 738         Record.push_back(VE.getValueID(C->getOperand(2)));
 739         break;
 740       case Instruction::ShuffleVector:
 741         // If the return type and argument types are the same, this is a
 742         // standard shufflevector instruction.  If the types are different,
 743         // then the shuffle is widening or truncating the input vectors, and
 744         // the argument type must also be encoded.
 745         if (C->getType() == C->getOperand(0)->getType()) {
 746           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 747         } else {
 748           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 749           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 750         }
 751         Record.push_back(VE.getValueID(C->getOperand(0)));
 752         Record.push_back(VE.getValueID(C->getOperand(1)));
 753         Record.push_back(VE.getValueID(C->getOperand(2)));
 754         break;
 755       case Instruction::ICmp:
 756       case Instruction::FCmp:
 757         Code = bitc::CST_CODE_CE_CMP;
 758         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 759         Record.push_back(VE.getValueID(C->getOperand(0)));
 760         Record.push_back(VE.getValueID(C->getOperand(1)));
 761         Record.push_back(CE->getPredicate());
 762         break;
 763       }
 764     } else {
 765       llvm_unreachable("Unknown constant!");
 766     }
 767     Stream.EmitRecord(Code, Record, AbbrevToUse);
 768     Record.clear();
 769   }
 770
 771   Stream.ExitBlock();
 772 }
 773
 774 static void WriteModuleConstants(const ValueEnumerator &VE,
 775                                  BitstreamWriter &Stream) {
 776   const ValueEnumerator::ValueList &Vals = VE.getValues();
 777
 778   // Find the first constant to emit, which is the first non-globalvalue value.
 779   // We know globalvalues have been emitted by WriteModuleInfo.
 780   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 781     if (!isa<GlobalValue>(Vals[i].first)) {
 782       WriteConstants(i, Vals.size(), VE, Stream, true);
 783       return;
 784     }
 785   }
 786 }
 787
 788 /// PushValueAndType - The file has to encode both the value and type id for
 789 /// many values, because we need to know what type to create for forward
 790 /// references.  However, most operands are not forward references, so this type
 791 /// field is not needed.
 792 ///
 793 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 794 /// instruction ID, then it is a forward reference, and it also includes the
 795 /// type ID.
 796 static bool PushValueAndType(const Value *V, unsigned InstID,
 797                              SmallVector<unsigned, 64> &Vals,
 798                              ValueEnumerator &VE) {
 799   unsigned ValID = VE.getValueID(V);
 800   Vals.push_back(ValID);
 801   if (ValID >= InstID) {
 802     Vals.push_back(VE.getTypeID(V->getType()));
 803     return true;
 804   }
 805   return false;
 806 }
 807
 808 /// WriteInstruction - Emit an instruction to the specified stream.
 809 static void WriteInstruction(const Instruction &I, unsigned InstID,
 810                              ValueEnumerator &VE, BitstreamWriter &Stream,
 811                              SmallVector<unsigned, 64> &Vals) {
 812   unsigned Code = 0;
 813   unsigned AbbrevToUse = 0;
 814   switch (I.getOpcode()) {
 815   default:
 816     if (Instruction::isCast(I.getOpcode())) {
 817       Code = bitc::FUNC_CODE_INST_CAST;
 818       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 819         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 820       Vals.push_back(VE.getTypeID(I.getType()));
 821       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 822     } else {
 823       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 824       Code = bitc::FUNC_CODE_INST_BINOP;
 825       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 826         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 827       Vals.push_back(VE.getValueID(I.getOperand(1)));
 828       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 829       uint64_t Flags = GetOptimizationFlags(&I);
 830       if (Flags != 0) {
 831         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 832           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 833         Vals.push_back(Flags);
 834       }
 835     }
 836     break;
 837
 838   case Instruction::GetElementPtr:
 839     Code = bitc::FUNC_CODE_INST_GEP;
 840     if (cast<GEPOperator>(&I)->isInBounds())
 841       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 842     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 843       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 844     break;
 845   case Instruction::ExtractValue: {
 846     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 847     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 848     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 849     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 850       Vals.push_back(*i);
 851     break;
 852   }
 853   case Instruction::InsertValue: {
 854     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 855     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 856     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 857     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 858     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 859       Vals.push_back(*i);
 860     break;
 861   }
 862   case Instruction::Select:
 863     Code = bitc::FUNC_CODE_INST_VSELECT;
 864     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 865     Vals.push_back(VE.getValueID(I.getOperand(2)));
 866     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 867     break;
 868   case Instruction::ExtractElement:
 869     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 870     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 871     Vals.push_back(VE.getValueID(I.getOperand(1)));
 872     break;
 873   case Instruction::InsertElement:
 874     Code = bitc::FUNC_CODE_INST_INSERTELT;
 875     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 876     Vals.push_back(VE.getValueID(I.getOperand(1)));
 877     Vals.push_back(VE.getValueID(I.getOperand(2)));
 878     break;
 879   case Instruction::ShuffleVector:
 880     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 881     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 882     Vals.push_back(VE.getValueID(I.getOperand(1)));
 883     Vals.push_back(VE.getValueID(I.getOperand(2)));
 884     break;
 885   case Instruction::ICmp:
 886   case Instruction::FCmp:
 887     // compare returning Int1Ty or vector of Int1Ty
 888     Code = bitc::FUNC_CODE_INST_CMP2;
 889     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 890     Vals.push_back(VE.getValueID(I.getOperand(1)));
 891     Vals.push_back(cast<CmpInst>(I).getPredicate());
 892     break;
 893
 894   case Instruction::Ret:
 895     {
 896       Code = bitc::FUNC_CODE_INST_RET;
 897       unsigned NumOperands = I.getNumOperands();
 898       if (NumOperands == 0)
 899         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 900       else if (NumOperands == 1) {
 901         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 902           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 903       } else {
 904         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 905           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 906       }
 907     }
 908     break;
 909   case Instruction::Br:
 910     {
 911       Code = bitc::FUNC_CODE_INST_BR;
 912       BranchInst &II(cast<BranchInst>(I));
 913       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 914       if (II.isConditional()) {
 915         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 916         Vals.push_back(VE.getValueID(II.getCondition()));
 917       }
 918     }
 919     break;
 920   case Instruction::Switch:
 921     Code = bitc::FUNC_CODE_INST_SWITCH;
 922     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 923     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 924       Vals.push_back(VE.getValueID(I.getOperand(i)));
 925     break;
 926   case Instruction::Invoke: {
 927     const InvokeInst *II = cast<InvokeInst>(&I);
 928     const Value *Callee(II->getCalledValue());
 929     const PointerType *PTy = cast<PointerType>(Callee->getType());
 930     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 931     Code = bitc::FUNC_CODE_INST_INVOKE;
 932
 933     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 934     Vals.push_back(II->getCallingConv());
 935     Vals.push_back(VE.getValueID(II->getNormalDest()));
 936     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 937     PushValueAndType(Callee, InstID, Vals, VE);
 938
 939     // Emit value #'s for the fixed parameters.
 940     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 941       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 942
 943     // Emit type/value pairs for varargs params.
 944     if (FTy->isVarArg()) {
 945       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 946            i != e; ++i)
 947         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 948     }
 949     break;
 950   }
 951   case Instruction::Unwind:
 952     Code = bitc::FUNC_CODE_INST_UNWIND;
 953     break;
 954   case Instruction::Unreachable:
 955     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 956     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 957     break;
 958
 959   case Instruction::PHI:
 960     Code = bitc::FUNC_CODE_INST_PHI;
 961     Vals.push_back(VE.getTypeID(I.getType()));
 962     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 963       Vals.push_back(VE.getValueID(I.getOperand(i)));
 964     break;
 965
 966   case Instruction::Malloc:
 967     Code = bitc::FUNC_CODE_INST_MALLOC;
 968     Vals.push_back(VE.getTypeID(I.getType()));
 969     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 970     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 971     break;
 972
 973   case Instruction::Free:
 974     Code = bitc::FUNC_CODE_INST_FREE;
 975     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 976     break;
 977
 978   case Instruction::Alloca:
 979     Code = bitc::FUNC_CODE_INST_ALLOCA;
 980     Vals.push_back(VE.getTypeID(I.getType()));
 981     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 982     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 983     break;
 984
 985   case Instruction::Load:
 986     Code = bitc::FUNC_CODE_INST_LOAD;
 987     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 988       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 989
 990     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 991     Vals.push_back(cast<LoadInst>(I).isVolatile());
 992     break;
 993   case Instruction::Store:
 994     Code = bitc::FUNC_CODE_INST_STORE2;
 995     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 996     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 997     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 998     Vals.push_back(cast<StoreInst>(I).isVolatile());
 999     break;
1000   case Instruction::Call: {
1001     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1002     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1003
1004     Code = bitc::FUNC_CODE_INST_CALL;
1005
1006     const CallInst *CI = cast<CallInst>(&I);
1007     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1008     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1009     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1010
1011     // Emit value #'s for the fixed parameters.
1012     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1013       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1014
1015     // Emit type/value pairs for varargs params.
1016     if (FTy->isVarArg()) {
1017       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1018       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1019            i != e; ++i)
1020         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1021     }
1022     break;
1023   }
1024   case Instruction::VAArg:
1025     Code = bitc::FUNC_CODE_INST_VAARG;
1026     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1027     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1028     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1029     break;
1030   }
1031
1032   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1033   Vals.clear();
1034 }
1035
1036 // Emit names for globals/functions etc.
1037 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1038                                   const ValueEnumerator &VE,
1039                                   BitstreamWriter &Stream) {
1040   if (VST.empty()) return;
1041   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1042
1043   // FIXME: Set up the abbrev, we know how many values there are!
1044   // FIXME: We know if the type names can use 7-bit ascii.
1045   SmallVector<unsigned, 64> NameVals;
1046
1047   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1048        SI != SE; ++SI) {
1049
1050     const ValueName &Name = *SI;
1051
1052     // Figure out the encoding to use for the name.
1053     bool is7Bit = true;
1054     bool isChar6 = true;
1055     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1056          C != E; ++C) {
1057       if (isChar6)
1058         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1059       if ((unsigned char)*C & 128) {
1060         is7Bit = false;
1061         break;  // don't bother scanning the rest.
1062       }
1063     }
1064
1065     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1066
1067     // VST_ENTRY:   [valueid, namechar x N]
1068     // VST_BBENTRY: [bbid, namechar x N]
1069     unsigned Code;
1070     if (isa<BasicBlock>(SI->getValue())) {
1071       Code = bitc::VST_CODE_BBENTRY;
1072       if (isChar6)
1073         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1074     } else {
1075       Code = bitc::VST_CODE_ENTRY;
1076       if (isChar6)
1077         AbbrevToUse = VST_ENTRY_6_ABBREV;
1078       else if (is7Bit)
1079         AbbrevToUse = VST_ENTRY_7_ABBREV;
1080     }
1081
1082     NameVals.push_back(VE.getValueID(SI->getValue()));
1083     for (const char *P = Name.getKeyData(),
1084          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1085       NameVals.push_back((unsigned char)*P);
1086
1087     // Emit the finished record.
1088     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1089     NameVals.clear();
1090   }
1091   Stream.ExitBlock();
1092 }
1093
1094 /// WriteFunction - Emit a function body to the module stream.
1095 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1096                           BitstreamWriter &Stream) {
1097   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1098   VE.incorporateFunction(F);
1099
1100   SmallVector<unsigned, 64> Vals;
1101
1102   // Emit the number of basic blocks, so the reader can create them ahead of
1103   // time.
1104   Vals.push_back(VE.getBasicBlocks().size());
1105   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1106   Vals.clear();
1107
1108   // If there are function-local constants, emit them now.
1109   unsigned CstStart, CstEnd;
1110   VE.getFunctionConstantRange(CstStart, CstEnd);
1111   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1112
1113   // Keep a running idea of what the instruction ID is.
1114   unsigned InstID = CstEnd;
1115
1116   // Finally, emit all the instructions, in order.
1117   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1118     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1119          I != E; ++I) {
1120       WriteInstruction(*I, InstID, VE, Stream, Vals);
1121       if (I->getType() != Type::VoidTy)
1122         ++InstID;
1123     }
1124
1125   // Emit names for all the instructions etc.
1126   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1127
1128   VE.purgeFunction();
1129   Stream.ExitBlock();
1130 }
1131
1132 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1133 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1134                                  const ValueEnumerator &VE,
1135                                  BitstreamWriter &Stream) {
1136   if (TST.empty()) return;
1137
1138   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1139
1140   // 7-bit fixed width VST_CODE_ENTRY strings.
1141   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1142   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1144                             Log2_32_Ceil(VE.getTypes().size()+1)));
1145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1147   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1148
1149   SmallVector<unsigned, 64> NameVals;
1150
1151   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1152        TI != TE; ++TI) {
1153     // TST_ENTRY: [typeid, namechar x N]
1154     NameVals.push_back(VE.getTypeID(TI->second));
1155
1156     const std::string &Str = TI->first;
1157     bool is7Bit = true;
1158     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1159       NameVals.push_back((unsigned char)Str[i]);
1160       if (Str[i] & 128)
1161         is7Bit = false;
1162     }
1163
1164     // Emit the finished record.
1165     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1166     NameVals.clear();
1167   }
1168
1169   Stream.ExitBlock();
1170 }
1171
1172 // Emit blockinfo, which defines the standard abbreviations etc.
1173 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1174   // We only want to emit block info records for blocks that have multiple
1175   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1176   // blocks can defined their abbrevs inline.
1177   Stream.EnterBlockInfoBlock(2);
1178
1179   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1180     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1181     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1184     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1185     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1186                                    Abbv) != VST_ENTRY_8_ABBREV)
1187       llvm_unreachable("Unexpected abbrev ordering!");
1188   }
1189
1190   { // 7-bit fixed width VST_ENTRY strings.
1191     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1192     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1196     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1197                                    Abbv) != VST_ENTRY_7_ABBREV)
1198       llvm_unreachable("Unexpected abbrev ordering!");
1199   }
1200   { // 6-bit char6 VST_ENTRY strings.
1201     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1202     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1203     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1206     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1207                                    Abbv) != VST_ENTRY_6_ABBREV)
1208       llvm_unreachable("Unexpected abbrev ordering!");
1209   }
1210   { // 6-bit char6 VST_BBENTRY strings.
1211     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1212     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1214     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1216     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1217                                    Abbv) != VST_BBENTRY_6_ABBREV)
1218       llvm_unreachable("Unexpected abbrev ordering!");
1219   }
1220
1221
1222
1223   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1224     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1225     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1227                               Log2_32_Ceil(VE.getTypes().size()+1)));
1228     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1229                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1230       llvm_unreachable("Unexpected abbrev ordering!");
1231   }
1232
1233   { // INTEGER abbrev for CONSTANTS_BLOCK.
1234     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1235     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1237     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1238                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1239       llvm_unreachable("Unexpected abbrev ordering!");
1240   }
1241
1242   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1243     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1244     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1247                               Log2_32_Ceil(VE.getTypes().size()+1)));
1248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1249
1250     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1251                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1252       llvm_unreachable("Unexpected abbrev ordering!");
1253   }
1254   { // NULL abbrev for CONSTANTS_BLOCK.
1255     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1256     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1257     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1258                                    Abbv) != CONSTANTS_NULL_Abbrev)
1259       llvm_unreachable("Unexpected abbrev ordering!");
1260   }
1261
1262   // FIXME: This should only use space for first class types!
1263
1264   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1265     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1266     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1270     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1271                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1272       llvm_unreachable("Unexpected abbrev ordering!");
1273   }
1274   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1275     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1276     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1280     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1281                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1282       llvm_unreachable("Unexpected abbrev ordering!");
1283   }
1284   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1285     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1286     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1291     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1292                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1293       llvm_unreachable("Unexpected abbrev ordering!");
1294   }
1295   { // INST_CAST abbrev for FUNCTION_BLOCK.
1296     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1297     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1300                               Log2_32_Ceil(VE.getTypes().size()+1)));
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1302     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1303                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1304       llvm_unreachable("Unexpected abbrev ordering!");
1305   }
1306
1307   { // INST_RET abbrev for FUNCTION_BLOCK.
1308     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1309     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1310     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1311                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1312       llvm_unreachable("Unexpected abbrev ordering!");
1313   }
1314   { // INST_RET abbrev for FUNCTION_BLOCK.
1315     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1316     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1318     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1319                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1320       llvm_unreachable("Unexpected abbrev ordering!");
1321   }
1322   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1323     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1324     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1325     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1326                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1327       llvm_unreachable("Unexpected abbrev ordering!");
1328   }
1329
1330   Stream.ExitBlock();
1331 }
1332
1333
1334 /// WriteModule - Emit the specified module to the bitstream.
1335 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1336   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1337
1338   // Emit the version number if it is non-zero.
1339   if (CurVersion) {
1340     SmallVector<unsigned, 1> Vals;
1341     Vals.push_back(CurVersion);
1342     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1343   }
1344
1345   // Analyze the module, enumerating globals, functions, etc.
1346   ValueEnumerator VE(M);
1347
1348   // Emit blockinfo, which defines the standard abbreviations etc.
1349   WriteBlockInfo(VE, Stream);
1350
1351   // Emit information about parameter attributes.
1352   WriteAttributeTable(VE, Stream);
1353
1354   // Emit information describing all of the types in the module.
1355   WriteTypeTable(VE, Stream);
1356
1357   // Emit top-level description of module, including target triple, inline asm,
1358   // descriptors for global variables, and function prototype info.
1359   WriteModuleInfo(M, VE, Stream);
1360
1361   // Emit constants.
1362   WriteModuleConstants(VE, Stream);
1363
1364   // Emit metadata.
1365   WriteModuleMetadata(VE, Stream);
1366
1367   // Emit function bodies.
1368   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1369     if (!I->isDeclaration())
1370       WriteFunction(*I, VE, Stream);
1371
1372   // Emit the type symbol table information.
1373   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1374
1375   // Emit names for globals/functions etc.
1376   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1377
1378   Stream.ExitBlock();
1379 }
1380
1381 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1382 /// header and trailer to make it compatible with the system archiver.  To do
1383 /// this we emit the following header, and then emit a trailer that pads the
1384 /// file out to be a multiple of 16 bytes.
1385 ///
1386 /// struct bc_header {
1387 ///   uint32_t Magic;         // 0x0B17C0DE
1388 ///   uint32_t Version;       // Version, currently always 0.
1389 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1390 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1391 ///   uint32_t CPUType;       // CPU specifier.
1392 ///   ... potentially more later ...
1393 /// };
1394 enum {
1395   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1396   DarwinBCHeaderSize = 5*4
1397 };
1398
1399 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1400                                const std::string &TT) {
1401   unsigned CPUType = ~0U;
1402
1403   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1404   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1405   // specific constants here because they are implicitly part of the Darwin ABI.
1406   enum {
1407     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1408     DARWIN_CPU_TYPE_X86        = 7,
1409     DARWIN_CPU_TYPE_POWERPC    = 18
1410   };
1411
1412   if (TT.find("x86_64-") == 0)
1413     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1414   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1415            TT[4] == '-' && TT[1] - '3' < 6)
1416     CPUType = DARWIN_CPU_TYPE_X86;
1417   else if (TT.find("powerpc-") == 0)
1418     CPUType = DARWIN_CPU_TYPE_POWERPC;
1419   else if (TT.find("powerpc64-") == 0)
1420     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1421
1422   // Traditional Bitcode starts after header.
1423   unsigned BCOffset = DarwinBCHeaderSize;
1424
1425   Stream.Emit(0x0B17C0DE, 32);
1426   Stream.Emit(0         , 32);  // Version.
1427   Stream.Emit(BCOffset  , 32);
1428   Stream.Emit(0         , 32);  // Filled in later.
1429   Stream.Emit(CPUType   , 32);
1430 }
1431
1432 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1433 /// finalize the header.
1434 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1435   // Update the size field in the header.
1436   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1437
1438   // If the file is not a multiple of 16 bytes, insert dummy padding.
1439   while (BufferSize & 15) {
1440     Stream.Emit(0, 8);
1441     ++BufferSize;
1442   }
1443 }
1444
1445
1446 /// WriteBitcodeToFile - Write the specified module to the specified output
1447 /// stream.
1448 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1449   raw_os_ostream RawOut(Out);
1450   // If writing to stdout, set binary mode.
1451   if (llvm::cout == Out)
1452     sys::Program::ChangeStdoutToBinary();
1453   WriteBitcodeToFile(M, RawOut);
1454 }
1455
1456 /// WriteBitcodeToFile - Write the specified module to the specified output
1457 /// stream.
1458 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1459   std::vector<unsigned char> Buffer;
1460   BitstreamWriter Stream(Buffer);
1461
1462   Buffer.reserve(256*1024);
1463
1464   WriteBitcodeToStream( M, Stream );
1465
1466   // If writing to stdout, set binary mode.
1467   if (&llvm::outs() == &Out)
1468     sys::Program::ChangeStdoutToBinary();
1469
1470   // Write the generated bitstream to "Out".
1471   Out.write((char*)&Buffer.front(), Buffer.size());
1472
1473   // Make sure it hits disk now.
1474   Out.flush();
1475 }
1476
1477 /// WriteBitcodeToStream - Write the specified module to the specified output
1478 /// stream.
1479 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1480   // If this is darwin, emit a file header and trailer if needed.
1481   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1482   if (isDarwin)
1483     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1484
1485   // Emit the file header.
1486   Stream.Emit((unsigned)'B', 8);
1487   Stream.Emit((unsigned)'C', 8);
1488   Stream.Emit(0x0, 4);
1489   Stream.Emit(0xC, 4);
1490   Stream.Emit(0xE, 4);
1491   Stream.Emit(0xD, 4);
1492
1493   // Emit the module.
1494   WriteModule(M, Stream);
1495
1496   if (isDarwin)
1497     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1498 }