lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Operator.h"
  24 #include "llvm/TypeSymbolTable.h"
  25 #include "llvm/ValueSymbolTable.h"
  26 #include "llvm/ADT/Triple.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/Support/Program.h"
  31 #include <cctype>
  32 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 static void WriteStringRecord(unsigned Code, const std::string &Str,
 105                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 106   SmallVector<unsigned, 64> Vals;
 107
 108   // Code: [strchar x N]
 109   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 110     Vals.push_back(Str[i]);
 111
 112   // Emit the finished record.
 113   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 114 }
 115
 116 // Emit information about parameter attributes.
 117 static void WriteAttributeTable(const ValueEnumerator &VE,
 118                                 BitstreamWriter &Stream) {
 119   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 120   if (Attrs.empty()) return;
 121
 122   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 123
 124   SmallVector<uint64_t, 64> Record;
 125   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 126     const AttrListPtr &A = Attrs[i];
 127     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 128       const AttributeWithIndex &PAWI = A.getSlot(i);
 129       Record.push_back(PAWI.Index);
 130
 131       // FIXME: remove in LLVM 3.0
 132       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 133       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 134       // 11 bits.
 135       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 136       if (PAWI.Attrs & Attribute::Alignment)
 137         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 138       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 139
 140       Record.push_back(FauxAttr);
 141     }
 142
 143     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 144     Record.clear();
 145   }
 146
 147   Stream.ExitBlock();
 148 }
 149
 150 /// WriteTypeTable - Write out the type table for a module.
 151 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 152   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 153
 154   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 155   SmallVector<uint64_t, 64> TypeVals;
 156
 157   // Abbrev for TYPE_CODE_POINTER.
 158   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 159   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 161                             Log2_32_Ceil(VE.getTypes().size()+1)));
 162   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 163   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 164
 165   // Abbrev for TYPE_CODE_FUNCTION.
 166   Abbv = new BitCodeAbbrev();
 167   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 169   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 172                             Log2_32_Ceil(VE.getTypes().size()+1)));
 173   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 174
 175   // Abbrev for TYPE_CODE_STRUCT.
 176   Abbv = new BitCodeAbbrev();
 177   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 181                             Log2_32_Ceil(VE.getTypes().size()+1)));
 182   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 183
 184   // Abbrev for TYPE_CODE_ARRAY.
 185   Abbv = new BitCodeAbbrev();
 186   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 189                             Log2_32_Ceil(VE.getTypes().size()+1)));
 190   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 191
 192   // Emit an entry count so the reader can reserve space.
 193   TypeVals.push_back(TypeList.size());
 194   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 195   TypeVals.clear();
 196
 197   // Loop over all of the types, emitting each in turn.
 198   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 199     const Type *T = TypeList[i];
 200     int AbbrevToUse = 0;
 201     unsigned Code = 0;
 202
 203     switch (T->getTypeID()) {
 204     default: llvm_unreachable("Unknown type!");
 205     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 206     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 207     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 208     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 209     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 210     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 211     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 212     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 213     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 214     case Type::X86_MMXTyID: Code = bitc::TYPE_CODE_X86_MMX; 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::ExternalLinkage:                 return 0;
 285   case GlobalValue::WeakAnyLinkage:                  return 1;
 286   case GlobalValue::AppendingLinkage:                return 2;
 287   case GlobalValue::InternalLinkage:                 return 3;
 288   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 289   case GlobalValue::DLLImportLinkage:                return 5;
 290   case GlobalValue::DLLExportLinkage:                return 6;
 291   case GlobalValue::ExternalWeakLinkage:             return 7;
 292   case GlobalValue::CommonLinkage:                   return 8;
 293   case GlobalValue::PrivateLinkage:                  return 9;
 294   case GlobalValue::WeakODRLinkage:                  return 10;
 295   case GlobalValue::LinkOnceODRLinkage:              return 11;
 296   case GlobalValue::AvailableExternallyLinkage:      return 12;
 297   case GlobalValue::LinkerPrivateLinkage:            return 13;
 298   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 299   case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
 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     //             unnamed_addr]
 408     Vals.push_back(VE.getTypeID(GV->getType()));
 409     Vals.push_back(GV->isConstant());
 410     Vals.push_back(GV->isDeclaration() ? 0 :
 411                    (VE.getValueID(GV->getInitializer()) + 1));
 412     Vals.push_back(getEncodedLinkage(GV));
 413     Vals.push_back(Log2_32(GV->getAlignment())+1);
 414     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 415     if (GV->isThreadLocal() ||
 416         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 417         GV->hasUnnamedAddr()) {
 418       Vals.push_back(getEncodedVisibility(GV));
 419       Vals.push_back(GV->isThreadLocal());
 420       Vals.push_back(GV->hasUnnamedAddr());
 421     } else {
 422       AbbrevToUse = SimpleGVarAbbrev;
 423     }
 424
 425     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 426     Vals.clear();
 427   }
 428
 429   // Emit the function proto information.
 430   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 431     // FUNCTION:  [type, callingconv, isproto, paramattr,
 432     //             linkage, alignment, section, visibility, gc, unnamed_addr]
 433     Vals.push_back(VE.getTypeID(F->getType()));
 434     Vals.push_back(F->getCallingConv());
 435     Vals.push_back(F->isDeclaration());
 436     Vals.push_back(getEncodedLinkage(F));
 437     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 438     Vals.push_back(Log2_32(F->getAlignment())+1);
 439     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 440     Vals.push_back(getEncodedVisibility(F));
 441     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 442     Vals.push_back(F->hasUnnamedAddr());
 443
 444     unsigned AbbrevToUse = 0;
 445     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 446     Vals.clear();
 447   }
 448
 449   // Emit the alias information.
 450   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 451        AI != E; ++AI) {
 452     Vals.push_back(VE.getTypeID(AI->getType()));
 453     Vals.push_back(VE.getValueID(AI->getAliasee()));
 454     Vals.push_back(getEncodedLinkage(AI));
 455     Vals.push_back(getEncodedVisibility(AI));
 456     unsigned AbbrevToUse = 0;
 457     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 458     Vals.clear();
 459   }
 460 }
 461
 462 static uint64_t GetOptimizationFlags(const Value *V) {
 463   uint64_t Flags = 0;
 464
 465   if (const OverflowingBinaryOperator *OBO =
 466         dyn_cast<OverflowingBinaryOperator>(V)) {
 467     if (OBO->hasNoSignedWrap())
 468       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 469     if (OBO->hasNoUnsignedWrap())
 470       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 471   } else if (const PossiblyExactOperator *PEO =
 472                dyn_cast<PossiblyExactOperator>(V)) {
 473     if (PEO->isExact())
 474       Flags |= 1 << bitc::PEO_EXACT;
 475   }
 476
 477   return Flags;
 478 }
 479
 480 static void WriteMDNode(const MDNode *N,
 481                         const ValueEnumerator &VE,
 482                         BitstreamWriter &Stream,
 483                         SmallVector<uint64_t, 64> &Record) {
 484   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 485     if (N->getOperand(i)) {
 486       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 487       Record.push_back(VE.getValueID(N->getOperand(i)));
 488     } else {
 489       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 490       Record.push_back(0);
 491     }
 492   }
 493   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 494                                            bitc::METADATA_NODE;
 495   Stream.EmitRecord(MDCode, Record, 0);
 496   Record.clear();
 497 }
 498
 499 static void WriteModuleMetadata(const Module *M,
 500                                 const ValueEnumerator &VE,
 501                                 BitstreamWriter &Stream) {
 502   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 503   bool StartedMetadataBlock = false;
 504   unsigned MDSAbbrev = 0;
 505   SmallVector<uint64_t, 64> Record;
 506   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 507
 508     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 509       if (!N->isFunctionLocal() || !N->getFunction()) {
 510         if (!StartedMetadataBlock) {
 511           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 512           StartedMetadataBlock = true;
 513         }
 514         WriteMDNode(N, VE, Stream, Record);
 515       }
 516     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 517       if (!StartedMetadataBlock)  {
 518         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 519
 520         // Abbrev for METADATA_STRING.
 521         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 522         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 523         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 524         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 525         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 526         StartedMetadataBlock = true;
 527       }
 528
 529       // Code: [strchar x N]
 530       Record.append(MDS->begin(), MDS->end());
 531
 532       // Emit the finished record.
 533       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 534       Record.clear();
 535     }
 536   }
 537
 538   // Write named metadata.
 539   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 540        E = M->named_metadata_end(); I != E; ++I) {
 541     const NamedMDNode *NMD = I;
 542     if (!StartedMetadataBlock)  {
 543       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 544       StartedMetadataBlock = true;
 545     }
 546
 547     // Write name.
 548     StringRef Str = NMD->getName();
 549     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 550       Record.push_back(Str[i]);
 551     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 552     Record.clear();
 553
 554     // Write named metadata operands.
 555     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 556       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 557     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 558     Record.clear();
 559   }
 560
 561   if (StartedMetadataBlock)
 562     Stream.ExitBlock();
 563 }
 564
 565 static void WriteFunctionLocalMetadata(const Function &F,
 566                                        const ValueEnumerator &VE,
 567                                        BitstreamWriter &Stream) {
 568   bool StartedMetadataBlock = false;
 569   SmallVector<uint64_t, 64> Record;
 570   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
 571   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 572     if (const MDNode *N = Vals[i])
 573       if (N->isFunctionLocal() && N->getFunction() == &F) {
 574         if (!StartedMetadataBlock) {
 575           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 576           StartedMetadataBlock = true;
 577         }
 578         WriteMDNode(N, VE, Stream, Record);
 579       }
 580
 581   if (StartedMetadataBlock)
 582     Stream.ExitBlock();
 583 }
 584
 585 static void WriteMetadataAttachment(const Function &F,
 586                                     const ValueEnumerator &VE,
 587                                     BitstreamWriter &Stream) {
 588   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 589
 590   SmallVector<uint64_t, 64> Record;
 591
 592   // Write metadata attachments
 593   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 594   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 595
 596   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 597     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 598          I != E; ++I) {
 599       MDs.clear();
 600       I->getAllMetadataOtherThanDebugLoc(MDs);
 601
 602       // If no metadata, ignore instruction.
 603       if (MDs.empty()) continue;
 604
 605       Record.push_back(VE.getInstructionID(I));
 606
 607       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 608         Record.push_back(MDs[i].first);
 609         Record.push_back(VE.getValueID(MDs[i].second));
 610       }
 611       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 612       Record.clear();
 613     }
 614
 615   Stream.ExitBlock();
 616 }
 617
 618 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 619   SmallVector<uint64_t, 64> Record;
 620
 621   // Write metadata kinds
 622   // METADATA_KIND - [n x [id, name]]
 623   SmallVector<StringRef, 4> Names;
 624   M->getMDKindNames(Names);
 625
 626   if (Names.empty()) return;
 627
 628   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 629
 630   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 631     Record.push_back(MDKindID);
 632     StringRef KName = Names[MDKindID];
 633     Record.append(KName.begin(), KName.end());
 634
 635     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 636     Record.clear();
 637   }
 638
 639   Stream.ExitBlock();
 640 }
 641
 642 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 643                            const ValueEnumerator &VE,
 644                            BitstreamWriter &Stream, bool isGlobal) {
 645   if (FirstVal == LastVal) return;
 646
 647   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 648
 649   unsigned AggregateAbbrev = 0;
 650   unsigned String8Abbrev = 0;
 651   unsigned CString7Abbrev = 0;
 652   unsigned CString6Abbrev = 0;
 653   // If this is a constant pool for the module, emit module-specific abbrevs.
 654   if (isGlobal) {
 655     // Abbrev for CST_CODE_AGGREGATE.
 656     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 657     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 658     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 659     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 660     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 661
 662     // Abbrev for CST_CODE_STRING.
 663     Abbv = new BitCodeAbbrev();
 664     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 666     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 667     String8Abbrev = Stream.EmitAbbrev(Abbv);
 668     // Abbrev for CST_CODE_CSTRING.
 669     Abbv = new BitCodeAbbrev();
 670     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 673     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 674     // Abbrev for CST_CODE_CSTRING.
 675     Abbv = new BitCodeAbbrev();
 676     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 679     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 680   }
 681
 682   SmallVector<uint64_t, 64> Record;
 683
 684   const ValueEnumerator::ValueList &Vals = VE.getValues();
 685   const Type *LastTy = 0;
 686   for (unsigned i = FirstVal; i != LastVal; ++i) {
 687     const Value *V = Vals[i].first;
 688     // If we need to switch types, do so now.
 689     if (V->getType() != LastTy) {
 690       LastTy = V->getType();
 691       Record.push_back(VE.getTypeID(LastTy));
 692       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 693                         CONSTANTS_SETTYPE_ABBREV);
 694       Record.clear();
 695     }
 696
 697     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 698       Record.push_back(unsigned(IA->hasSideEffects()) |
 699                        unsigned(IA->isAlignStack()) << 1);
 700
 701       // Add the asm string.
 702       const std::string &AsmStr = IA->getAsmString();
 703       Record.push_back(AsmStr.size());
 704       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 705         Record.push_back(AsmStr[i]);
 706
 707       // Add the constraint string.
 708       const std::string &ConstraintStr = IA->getConstraintString();
 709       Record.push_back(ConstraintStr.size());
 710       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 711         Record.push_back(ConstraintStr[i]);
 712       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 713       Record.clear();
 714       continue;
 715     }
 716     const Constant *C = cast<Constant>(V);
 717     unsigned Code = -1U;
 718     unsigned AbbrevToUse = 0;
 719     if (C->isNullValue()) {
 720       Code = bitc::CST_CODE_NULL;
 721     } else if (isa<UndefValue>(C)) {
 722       Code = bitc::CST_CODE_UNDEF;
 723     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 724       if (IV->getBitWidth() <= 64) {
 725         uint64_t V = IV->getSExtValue();
 726         if ((int64_t)V >= 0)
 727           Record.push_back(V << 1);
 728         else
 729           Record.push_back((-V << 1) | 1);
 730         Code = bitc::CST_CODE_INTEGER;
 731         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 732       } else {                             // Wide integers, > 64 bits in size.
 733         // We have an arbitrary precision integer value to write whose
 734         // bit width is > 64. However, in canonical unsigned integer
 735         // format it is likely that the high bits are going to be zero.
 736         // So, we only write the number of active words.
 737         unsigned NWords = IV->getValue().getActiveWords();
 738         const uint64_t *RawWords = IV->getValue().getRawData();
 739         for (unsigned i = 0; i != NWords; ++i) {
 740           int64_t V = RawWords[i];
 741           if (V >= 0)
 742             Record.push_back(V << 1);
 743           else
 744             Record.push_back((-V << 1) | 1);
 745         }
 746         Code = bitc::CST_CODE_WIDE_INTEGER;
 747       }
 748     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 749       Code = bitc::CST_CODE_FLOAT;
 750       const Type *Ty = CFP->getType();
 751       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 752         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 753       } else if (Ty->isX86_FP80Ty()) {
 754         // api needed to prevent premature destruction
 755         // bits are not in the same order as a normal i80 APInt, compensate.
 756         APInt api = CFP->getValueAPF().bitcastToAPInt();
 757         const uint64_t *p = api.getRawData();
 758         Record.push_back((p[1] << 48) | (p[0] >> 16));
 759         Record.push_back(p[0] & 0xffffLL);
 760       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 761         APInt api = CFP->getValueAPF().bitcastToAPInt();
 762         const uint64_t *p = api.getRawData();
 763         Record.push_back(p[0]);
 764         Record.push_back(p[1]);
 765       } else {
 766         assert (0 && "Unknown FP type!");
 767       }
 768     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 769       const ConstantArray *CA = cast<ConstantArray>(C);
 770       // Emit constant strings specially.
 771       unsigned NumOps = CA->getNumOperands();
 772       // If this is a null-terminated string, use the denser CSTRING encoding.
 773       if (CA->getOperand(NumOps-1)->isNullValue()) {
 774         Code = bitc::CST_CODE_CSTRING;
 775         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 776       } else {
 777         Code = bitc::CST_CODE_STRING;
 778         AbbrevToUse = String8Abbrev;
 779       }
 780       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 781       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 782       for (unsigned i = 0; i != NumOps; ++i) {
 783         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 784         Record.push_back(V);
 785         isCStr7 &= (V & 128) == 0;
 786         if (isCStrChar6)
 787           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 788       }
 789
 790       if (isCStrChar6)
 791         AbbrevToUse = CString6Abbrev;
 792       else if (isCStr7)
 793         AbbrevToUse = CString7Abbrev;
 794     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 795                isa<ConstantVector>(V)) {
 796       Code = bitc::CST_CODE_AGGREGATE;
 797       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 798         Record.push_back(VE.getValueID(C->getOperand(i)));
 799       AbbrevToUse = AggregateAbbrev;
 800     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 801       switch (CE->getOpcode()) {
 802       default:
 803         if (Instruction::isCast(CE->getOpcode())) {
 804           Code = bitc::CST_CODE_CE_CAST;
 805           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 806           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 807           Record.push_back(VE.getValueID(C->getOperand(0)));
 808           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 809         } else {
 810           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 811           Code = bitc::CST_CODE_CE_BINOP;
 812           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 813           Record.push_back(VE.getValueID(C->getOperand(0)));
 814           Record.push_back(VE.getValueID(C->getOperand(1)));
 815           uint64_t Flags = GetOptimizationFlags(CE);
 816           if (Flags != 0)
 817             Record.push_back(Flags);
 818         }
 819         break;
 820       case Instruction::GetElementPtr:
 821         Code = bitc::CST_CODE_CE_GEP;
 822         if (cast<GEPOperator>(C)->isInBounds())
 823           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 824         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 825           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 826           Record.push_back(VE.getValueID(C->getOperand(i)));
 827         }
 828         break;
 829       case Instruction::Select:
 830         Code = bitc::CST_CODE_CE_SELECT;
 831         Record.push_back(VE.getValueID(C->getOperand(0)));
 832         Record.push_back(VE.getValueID(C->getOperand(1)));
 833         Record.push_back(VE.getValueID(C->getOperand(2)));
 834         break;
 835       case Instruction::ExtractElement:
 836         Code = bitc::CST_CODE_CE_EXTRACTELT;
 837         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 838         Record.push_back(VE.getValueID(C->getOperand(0)));
 839         Record.push_back(VE.getValueID(C->getOperand(1)));
 840         break;
 841       case Instruction::InsertElement:
 842         Code = bitc::CST_CODE_CE_INSERTELT;
 843         Record.push_back(VE.getValueID(C->getOperand(0)));
 844         Record.push_back(VE.getValueID(C->getOperand(1)));
 845         Record.push_back(VE.getValueID(C->getOperand(2)));
 846         break;
 847       case Instruction::ShuffleVector:
 848         // If the return type and argument types are the same, this is a
 849         // standard shufflevector instruction.  If the types are different,
 850         // then the shuffle is widening or truncating the input vectors, and
 851         // the argument type must also be encoded.
 852         if (C->getType() == C->getOperand(0)->getType()) {
 853           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 854         } else {
 855           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 856           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 857         }
 858         Record.push_back(VE.getValueID(C->getOperand(0)));
 859         Record.push_back(VE.getValueID(C->getOperand(1)));
 860         Record.push_back(VE.getValueID(C->getOperand(2)));
 861         break;
 862       case Instruction::ICmp:
 863       case Instruction::FCmp:
 864         Code = bitc::CST_CODE_CE_CMP;
 865         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 866         Record.push_back(VE.getValueID(C->getOperand(0)));
 867         Record.push_back(VE.getValueID(C->getOperand(1)));
 868         Record.push_back(CE->getPredicate());
 869         break;
 870       }
 871     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 872       Code = bitc::CST_CODE_BLOCKADDRESS;
 873       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 874       Record.push_back(VE.getValueID(BA->getFunction()));
 875       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 876     } else {
 877 #ifndef NDEBUG
 878       C->dump();
 879 #endif
 880       llvm_unreachable("Unknown constant!");
 881     }
 882     Stream.EmitRecord(Code, Record, AbbrevToUse);
 883     Record.clear();
 884   }
 885
 886   Stream.ExitBlock();
 887 }
 888
 889 static void WriteModuleConstants(const ValueEnumerator &VE,
 890                                  BitstreamWriter &Stream) {
 891   const ValueEnumerator::ValueList &Vals = VE.getValues();
 892
 893   // Find the first constant to emit, which is the first non-globalvalue value.
 894   // We know globalvalues have been emitted by WriteModuleInfo.
 895   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 896     if (!isa<GlobalValue>(Vals[i].first)) {
 897       WriteConstants(i, Vals.size(), VE, Stream, true);
 898       return;
 899     }
 900   }
 901 }
 902
 903 /// PushValueAndType - The file has to encode both the value and type id for
 904 /// many values, because we need to know what type to create for forward
 905 /// references.  However, most operands are not forward references, so this type
 906 /// field is not needed.
 907 ///
 908 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 909 /// instruction ID, then it is a forward reference, and it also includes the
 910 /// type ID.
 911 static bool PushValueAndType(const Value *V, unsigned InstID,
 912                              SmallVector<unsigned, 64> &Vals,
 913                              ValueEnumerator &VE) {
 914   unsigned ValID = VE.getValueID(V);
 915   Vals.push_back(ValID);
 916   if (ValID >= InstID) {
 917     Vals.push_back(VE.getTypeID(V->getType()));
 918     return true;
 919   }
 920   return false;
 921 }
 922
 923 /// WriteInstruction - Emit an instruction to the specified stream.
 924 static void WriteInstruction(const Instruction &I, unsigned InstID,
 925                              ValueEnumerator &VE, BitstreamWriter &Stream,
 926                              SmallVector<unsigned, 64> &Vals) {
 927   unsigned Code = 0;
 928   unsigned AbbrevToUse = 0;
 929   VE.setInstructionID(&I);
 930   switch (I.getOpcode()) {
 931   default:
 932     if (Instruction::isCast(I.getOpcode())) {
 933       Code = bitc::FUNC_CODE_INST_CAST;
 934       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 935         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 936       Vals.push_back(VE.getTypeID(I.getType()));
 937       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 938     } else {
 939       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 940       Code = bitc::FUNC_CODE_INST_BINOP;
 941       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 942         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 943       Vals.push_back(VE.getValueID(I.getOperand(1)));
 944       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 945       uint64_t Flags = GetOptimizationFlags(&I);
 946       if (Flags != 0) {
 947         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 948           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 949         Vals.push_back(Flags);
 950       }
 951     }
 952     break;
 953
 954   case Instruction::GetElementPtr:
 955     Code = bitc::FUNC_CODE_INST_GEP;
 956     if (cast<GEPOperator>(&I)->isInBounds())
 957       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 958     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 959       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 960     break;
 961   case Instruction::ExtractValue: {
 962     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 963     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 964     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 965     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 966       Vals.push_back(*i);
 967     break;
 968   }
 969   case Instruction::InsertValue: {
 970     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 971     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 972     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 973     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 974     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 975       Vals.push_back(*i);
 976     break;
 977   }
 978   case Instruction::Select:
 979     Code = bitc::FUNC_CODE_INST_VSELECT;
 980     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 981     Vals.push_back(VE.getValueID(I.getOperand(2)));
 982     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 983     break;
 984   case Instruction::ExtractElement:
 985     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 986     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 987     Vals.push_back(VE.getValueID(I.getOperand(1)));
 988     break;
 989   case Instruction::InsertElement:
 990     Code = bitc::FUNC_CODE_INST_INSERTELT;
 991     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 992     Vals.push_back(VE.getValueID(I.getOperand(1)));
 993     Vals.push_back(VE.getValueID(I.getOperand(2)));
 994     break;
 995   case Instruction::ShuffleVector:
 996     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 997     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 998     Vals.push_back(VE.getValueID(I.getOperand(1)));
 999     Vals.push_back(VE.getValueID(I.getOperand(2)));
1000     break;
1001   case Instruction::ICmp:
1002   case Instruction::FCmp:
1003     // compare returning Int1Ty or vector of Int1Ty
1004     Code = bitc::FUNC_CODE_INST_CMP2;
1005     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1006     Vals.push_back(VE.getValueID(I.getOperand(1)));
1007     Vals.push_back(cast<CmpInst>(I).getPredicate());
1008     break;
1009
1010   case Instruction::Ret:
1011     {
1012       Code = bitc::FUNC_CODE_INST_RET;
1013       unsigned NumOperands = I.getNumOperands();
1014       if (NumOperands == 0)
1015         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1016       else if (NumOperands == 1) {
1017         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1018           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1019       } else {
1020         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1021           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1022       }
1023     }
1024     break;
1025   case Instruction::Br:
1026     {
1027       Code = bitc::FUNC_CODE_INST_BR;
1028       BranchInst &II = cast<BranchInst>(I);
1029       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1030       if (II.isConditional()) {
1031         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1032         Vals.push_back(VE.getValueID(II.getCondition()));
1033       }
1034     }
1035     break;
1036   case Instruction::Switch:
1037     Code = bitc::FUNC_CODE_INST_SWITCH;
1038     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1039     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1040       Vals.push_back(VE.getValueID(I.getOperand(i)));
1041     break;
1042   case Instruction::IndirectBr:
1043     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1044     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1045     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1046       Vals.push_back(VE.getValueID(I.getOperand(i)));
1047     break;
1048
1049   case Instruction::Invoke: {
1050     const InvokeInst *II = cast<InvokeInst>(&I);
1051     const Value *Callee(II->getCalledValue());
1052     const PointerType *PTy = cast<PointerType>(Callee->getType());
1053     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1054     Code = bitc::FUNC_CODE_INST_INVOKE;
1055
1056     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1057     Vals.push_back(II->getCallingConv());
1058     Vals.push_back(VE.getValueID(II->getNormalDest()));
1059     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1060     PushValueAndType(Callee, InstID, Vals, VE);
1061
1062     // Emit value #'s for the fixed parameters.
1063     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1064       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1065
1066     // Emit type/value pairs for varargs params.
1067     if (FTy->isVarArg()) {
1068       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1069            i != e; ++i)
1070         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1071     }
1072     break;
1073   }
1074   case Instruction::Unwind:
1075     Code = bitc::FUNC_CODE_INST_UNWIND;
1076     break;
1077   case Instruction::Unreachable:
1078     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1079     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1080     break;
1081
1082   case Instruction::PHI: {
1083     const PHINode &PN = cast<PHINode>(I);
1084     Code = bitc::FUNC_CODE_INST_PHI;
1085     Vals.push_back(VE.getTypeID(PN.getType()));
1086     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1087       Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1088       Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1089     }
1090     break;
1091   }
1092
1093   case Instruction::Alloca:
1094     Code = bitc::FUNC_CODE_INST_ALLOCA;
1095     Vals.push_back(VE.getTypeID(I.getType()));
1096     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1097     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1098     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1099     break;
1100
1101   case Instruction::Load:
1102     Code = bitc::FUNC_CODE_INST_LOAD;
1103     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1104       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1105
1106     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1107     Vals.push_back(cast<LoadInst>(I).isVolatile());
1108     break;
1109   case Instruction::Store:
1110     Code = bitc::FUNC_CODE_INST_STORE;
1111     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1112     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1113     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1114     Vals.push_back(cast<StoreInst>(I).isVolatile());
1115     break;
1116   case Instruction::Call: {
1117     const CallInst &CI = cast<CallInst>(I);
1118     const PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1119     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1120
1121     Code = bitc::FUNC_CODE_INST_CALL;
1122
1123     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1124     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1125     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1126
1127     // Emit value #'s for the fixed parameters.
1128     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1129       Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1130
1131     // Emit type/value pairs for varargs params.
1132     if (FTy->isVarArg()) {
1133       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1134            i != e; ++i)
1135         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1136     }
1137     break;
1138   }
1139   case Instruction::VAArg:
1140     Code = bitc::FUNC_CODE_INST_VAARG;
1141     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1142     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1143     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1144     break;
1145   }
1146
1147   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1148   Vals.clear();
1149 }
1150
1151 // Emit names for globals/functions etc.
1152 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1153                                   const ValueEnumerator &VE,
1154                                   BitstreamWriter &Stream) {
1155   if (VST.empty()) return;
1156   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1157
1158   // FIXME: Set up the abbrev, we know how many values there are!
1159   // FIXME: We know if the type names can use 7-bit ascii.
1160   SmallVector<unsigned, 64> NameVals;
1161
1162   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1163        SI != SE; ++SI) {
1164
1165     const ValueName &Name = *SI;
1166
1167     // Figure out the encoding to use for the name.
1168     bool is7Bit = true;
1169     bool isChar6 = true;
1170     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1171          C != E; ++C) {
1172       if (isChar6)
1173         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1174       if ((unsigned char)*C & 128) {
1175         is7Bit = false;
1176         break;  // don't bother scanning the rest.
1177       }
1178     }
1179
1180     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1181
1182     // VST_ENTRY:   [valueid, namechar x N]
1183     // VST_BBENTRY: [bbid, namechar x N]
1184     unsigned Code;
1185     if (isa<BasicBlock>(SI->getValue())) {
1186       Code = bitc::VST_CODE_BBENTRY;
1187       if (isChar6)
1188         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1189     } else {
1190       Code = bitc::VST_CODE_ENTRY;
1191       if (isChar6)
1192         AbbrevToUse = VST_ENTRY_6_ABBREV;
1193       else if (is7Bit)
1194         AbbrevToUse = VST_ENTRY_7_ABBREV;
1195     }
1196
1197     NameVals.push_back(VE.getValueID(SI->getValue()));
1198     for (const char *P = Name.getKeyData(),
1199          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1200       NameVals.push_back((unsigned char)*P);
1201
1202     // Emit the finished record.
1203     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1204     NameVals.clear();
1205   }
1206   Stream.ExitBlock();
1207 }
1208
1209 /// WriteFunction - Emit a function body to the module stream.
1210 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1211                           BitstreamWriter &Stream) {
1212   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1213   VE.incorporateFunction(F);
1214
1215   SmallVector<unsigned, 64> Vals;
1216
1217   // Emit the number of basic blocks, so the reader can create them ahead of
1218   // time.
1219   Vals.push_back(VE.getBasicBlocks().size());
1220   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1221   Vals.clear();
1222
1223   // If there are function-local constants, emit them now.
1224   unsigned CstStart, CstEnd;
1225   VE.getFunctionConstantRange(CstStart, CstEnd);
1226   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1227
1228   // If there is function-local metadata, emit it now.
1229   WriteFunctionLocalMetadata(F, VE, Stream);
1230
1231   // Keep a running idea of what the instruction ID is.
1232   unsigned InstID = CstEnd;
1233
1234   bool NeedsMetadataAttachment = false;
1235
1236   DebugLoc LastDL;
1237
1238   // Finally, emit all the instructions, in order.
1239   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1240     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1241          I != E; ++I) {
1242       WriteInstruction(*I, InstID, VE, Stream, Vals);
1243
1244       if (!I->getType()->isVoidTy())
1245         ++InstID;
1246
1247       // If the instruction has metadata, write a metadata attachment later.
1248       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1249
1250       // If the instruction has a debug location, emit it.
1251       DebugLoc DL = I->getDebugLoc();
1252       if (DL.isUnknown()) {
1253         // nothing todo.
1254       } else if (DL == LastDL) {
1255         // Just repeat the same debug loc as last time.
1256         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1257       } else {
1258         MDNode *Scope, *IA;
1259         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1260
1261         Vals.push_back(DL.getLine());
1262         Vals.push_back(DL.getCol());
1263         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1264         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1265         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1266         Vals.clear();
1267
1268         LastDL = DL;
1269       }
1270     }
1271
1272   // Emit names for all the instructions etc.
1273   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1274
1275   if (NeedsMetadataAttachment)
1276     WriteMetadataAttachment(F, VE, Stream);
1277   VE.purgeFunction();
1278   Stream.ExitBlock();
1279 }
1280
1281 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1282 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1283                                  const ValueEnumerator &VE,
1284                                  BitstreamWriter &Stream) {
1285   if (TST.empty()) return;
1286
1287   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1288
1289   // 7-bit fixed width VST_CODE_ENTRY strings.
1290   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1291   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1292   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1293                             Log2_32_Ceil(VE.getTypes().size()+1)));
1294   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1295   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1296   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1297
1298   SmallVector<unsigned, 64> NameVals;
1299
1300   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1301        TI != TE; ++TI) {
1302     // TST_ENTRY: [typeid, namechar x N]
1303     NameVals.push_back(VE.getTypeID(TI->second));
1304
1305     const std::string &Str = TI->first;
1306     bool is7Bit = true;
1307     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1308       NameVals.push_back((unsigned char)Str[i]);
1309       if (Str[i] & 128)
1310         is7Bit = false;
1311     }
1312
1313     // Emit the finished record.
1314     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1315     NameVals.clear();
1316   }
1317
1318   Stream.ExitBlock();
1319 }
1320
1321 // Emit blockinfo, which defines the standard abbreviations etc.
1322 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1323   // We only want to emit block info records for blocks that have multiple
1324   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1325   // blocks can defined their abbrevs inline.
1326   Stream.EnterBlockInfoBlock(2);
1327
1328   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1329     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1334     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1335                                    Abbv) != VST_ENTRY_8_ABBREV)
1336       llvm_unreachable("Unexpected abbrev ordering!");
1337   }
1338
1339   { // 7-bit fixed width VST_ENTRY strings.
1340     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1341     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1345     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1346                                    Abbv) != VST_ENTRY_7_ABBREV)
1347       llvm_unreachable("Unexpected abbrev ordering!");
1348   }
1349   { // 6-bit char6 VST_ENTRY strings.
1350     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1351     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1355     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1356                                    Abbv) != VST_ENTRY_6_ABBREV)
1357       llvm_unreachable("Unexpected abbrev ordering!");
1358   }
1359   { // 6-bit char6 VST_BBENTRY strings.
1360     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1361     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1362     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1365     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1366                                    Abbv) != VST_BBENTRY_6_ABBREV)
1367       llvm_unreachable("Unexpected abbrev ordering!");
1368   }
1369
1370
1371
1372   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1373     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1374     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1376                               Log2_32_Ceil(VE.getTypes().size()+1)));
1377     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1378                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1379       llvm_unreachable("Unexpected abbrev ordering!");
1380   }
1381
1382   { // INTEGER abbrev for CONSTANTS_BLOCK.
1383     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1384     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1386     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1387                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1388       llvm_unreachable("Unexpected abbrev ordering!");
1389   }
1390
1391   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1392     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1393     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1396                               Log2_32_Ceil(VE.getTypes().size()+1)));
1397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1398
1399     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1400                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1401       llvm_unreachable("Unexpected abbrev ordering!");
1402   }
1403   { // NULL abbrev for CONSTANTS_BLOCK.
1404     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1405     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1406     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1407                                    Abbv) != CONSTANTS_NULL_Abbrev)
1408       llvm_unreachable("Unexpected abbrev ordering!");
1409   }
1410
1411   // FIXME: This should only use space for first class types!
1412
1413   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1414     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1415     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1419     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1420                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1421       llvm_unreachable("Unexpected abbrev ordering!");
1422   }
1423   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1424     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1425     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1429     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1430                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1431       llvm_unreachable("Unexpected abbrev ordering!");
1432   }
1433   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1434     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1435     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1440     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1441                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1442       llvm_unreachable("Unexpected abbrev ordering!");
1443   }
1444   { // INST_CAST abbrev for FUNCTION_BLOCK.
1445     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1446     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1449                               Log2_32_Ceil(VE.getTypes().size()+1)));
1450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1451     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1452                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1453       llvm_unreachable("Unexpected abbrev ordering!");
1454   }
1455
1456   { // INST_RET abbrev for FUNCTION_BLOCK.
1457     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1458     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1459     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1460                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1461       llvm_unreachable("Unexpected abbrev ordering!");
1462   }
1463   { // INST_RET abbrev for FUNCTION_BLOCK.
1464     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1465     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1467     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1468                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1469       llvm_unreachable("Unexpected abbrev ordering!");
1470   }
1471   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1472     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1473     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1474     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1475                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1476       llvm_unreachable("Unexpected abbrev ordering!");
1477   }
1478
1479   Stream.ExitBlock();
1480 }
1481
1482
1483 /// WriteModule - Emit the specified module to the bitstream.
1484 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1485   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1486
1487   // Emit the version number if it is non-zero.
1488   if (CurVersion) {
1489     SmallVector<unsigned, 1> Vals;
1490     Vals.push_back(CurVersion);
1491     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1492   }
1493
1494   // Analyze the module, enumerating globals, functions, etc.
1495   ValueEnumerator VE(M);
1496
1497   // Emit blockinfo, which defines the standard abbreviations etc.
1498   WriteBlockInfo(VE, Stream);
1499
1500   // Emit information about parameter attributes.
1501   WriteAttributeTable(VE, Stream);
1502
1503   // Emit information describing all of the types in the module.
1504   WriteTypeTable(VE, Stream);
1505
1506   // Emit top-level description of module, including target triple, inline asm,
1507   // descriptors for global variables, and function prototype info.
1508   WriteModuleInfo(M, VE, Stream);
1509
1510   // Emit constants.
1511   WriteModuleConstants(VE, Stream);
1512
1513   // Emit metadata.
1514   WriteModuleMetadata(M, VE, Stream);
1515
1516   // Emit function bodies.
1517   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1518     if (!F->isDeclaration())
1519       WriteFunction(*F, VE, Stream);
1520
1521   // Emit metadata.
1522   WriteModuleMetadataStore(M, Stream);
1523
1524   // Emit the type symbol table information.
1525   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1526
1527   // Emit names for globals/functions etc.
1528   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1529
1530   Stream.ExitBlock();
1531 }
1532
1533 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1534 /// header and trailer to make it compatible with the system archiver.  To do
1535 /// this we emit the following header, and then emit a trailer that pads the
1536 /// file out to be a multiple of 16 bytes.
1537 ///
1538 /// struct bc_header {
1539 ///   uint32_t Magic;         // 0x0B17C0DE
1540 ///   uint32_t Version;       // Version, currently always 0.
1541 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1542 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1543 ///   uint32_t CPUType;       // CPU specifier.
1544 ///   ... potentially more later ...
1545 /// };
1546 enum {
1547   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1548   DarwinBCHeaderSize = 5*4
1549 };
1550
1551 static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
1552   unsigned CPUType = ~0U;
1553
1554   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1555   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1556   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1557   // specific constants here because they are implicitly part of the Darwin ABI.
1558   enum {
1559     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1560     DARWIN_CPU_TYPE_X86        = 7,
1561     DARWIN_CPU_TYPE_ARM        = 12,
1562     DARWIN_CPU_TYPE_POWERPC    = 18
1563   };
1564
1565   Triple::ArchType Arch = TT.getArch();
1566   if (Arch == Triple::x86_64)
1567     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1568   else if (Arch == Triple::x86)
1569     CPUType = DARWIN_CPU_TYPE_X86;
1570   else if (Arch == Triple::ppc)
1571     CPUType = DARWIN_CPU_TYPE_POWERPC;
1572   else if (Arch == Triple::ppc64)
1573     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1574   else if (Arch == Triple::arm || Arch == Triple::thumb)
1575     CPUType = DARWIN_CPU_TYPE_ARM;
1576
1577   // Traditional Bitcode starts after header.
1578   unsigned BCOffset = DarwinBCHeaderSize;
1579
1580   Stream.Emit(0x0B17C0DE, 32);
1581   Stream.Emit(0         , 32);  // Version.
1582   Stream.Emit(BCOffset  , 32);
1583   Stream.Emit(0         , 32);  // Filled in later.
1584   Stream.Emit(CPUType   , 32);
1585 }
1586
1587 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1588 /// finalize the header.
1589 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1590   // Update the size field in the header.
1591   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1592
1593   // If the file is not a multiple of 16 bytes, insert dummy padding.
1594   while (BufferSize & 15) {
1595     Stream.Emit(0, 8);
1596     ++BufferSize;
1597   }
1598 }
1599
1600
1601 /// WriteBitcodeToFile - Write the specified module to the specified output
1602 /// stream.
1603 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1604   std::vector<unsigned char> Buffer;
1605   BitstreamWriter Stream(Buffer);
1606
1607   Buffer.reserve(256*1024);
1608
1609   WriteBitcodeToStream( M, Stream );
1610
1611   // Write the generated bitstream to "Out".
1612   Out.write((char*)&Buffer.front(), Buffer.size());
1613 }
1614
1615 /// WriteBitcodeToStream - Write the specified module to the specified output
1616 /// stream.
1617 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1618   // If this is darwin or another generic macho target, emit a file header and
1619   // trailer if needed.
1620   Triple TT(M->getTargetTriple());
1621   if (TT.isOSDarwin())
1622     EmitDarwinBCHeader(Stream, TT);
1623
1624   // Emit the file header.
1625   Stream.Emit((unsigned)'B', 8);
1626   Stream.Emit((unsigned)'C', 8);
1627   Stream.Emit(0x0, 4);
1628   Stream.Emit(0xC, 4);
1629   Stream.Emit(0xE, 4);
1630   Stream.Emit(0xD, 4);
1631
1632   // Emit the module.
1633   WriteModule(M, Stream);
1634
1635   if (TT.isOSDarwin())
1636     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1637 }