contrib/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Operator.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/ADT/Triple.h"
  26 #include "llvm/Support/ErrorHandling.h"
  27 #include "llvm/Support/MathExtras.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include "llvm/Support/Program.h"
  30 #include <cctype>
  31 #include <map>
  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, StringRef 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     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 111       AbbrevToUse = 0;
 112     Vals.push_back(Str[i]);
 113   }
 114
 115   // Emit the finished record.
 116   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 117 }
 118
 119 // Emit information about parameter attributes.
 120 static void WriteAttributeTable(const ValueEnumerator &VE,
 121                                 BitstreamWriter &Stream) {
 122   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 123   if (Attrs.empty()) return;
 124
 125   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 126
 127   SmallVector<uint64_t, 64> Record;
 128   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 129     const AttrListPtr &A = Attrs[i];
 130     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 131       const AttributeWithIndex &PAWI = A.getSlot(i);
 132       Record.push_back(PAWI.Index);
 133
 134       // FIXME: remove in LLVM 3.0
 135       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 136       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 137       // 11 bits.
 138       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 139       if (PAWI.Attrs & Attribute::Alignment)
 140         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 141       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 142
 143       Record.push_back(FauxAttr);
 144     }
 145
 146     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 147     Record.clear();
 148   }
 149
 150   Stream.ExitBlock();
 151 }
 152
 153 /// WriteTypeTable - Write out the type table for a module.
 154 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 155   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 156
 157   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 158   SmallVector<uint64_t, 64> TypeVals;
 159
 160   // Abbrev for TYPE_CODE_POINTER.
 161   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 162   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 164                             Log2_32_Ceil(VE.getTypes().size()+1)));
 165   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 166   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 167
 168   // Abbrev for TYPE_CODE_FUNCTION.
 169   Abbv = new BitCodeAbbrev();
 170   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 172   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 175                             Log2_32_Ceil(VE.getTypes().size()+1)));
 176   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 177
 178   // Abbrev for TYPE_CODE_STRUCT_ANON.
 179   Abbv = new BitCodeAbbrev();
 180   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 184                             Log2_32_Ceil(VE.getTypes().size()+1)));
 185   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 186
 187   // Abbrev for TYPE_CODE_STRUCT_NAME.
 188   Abbv = new BitCodeAbbrev();
 189   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 192   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 193
 194   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 195   Abbv = new BitCodeAbbrev();
 196   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 200                             Log2_32_Ceil(VE.getTypes().size()+1)));
 201   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 202
 203
 204   // Abbrev for TYPE_CODE_ARRAY.
 205   Abbv = new BitCodeAbbrev();
 206   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 209                             Log2_32_Ceil(VE.getTypes().size()+1)));
 210   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 211
 212   // Emit an entry count so the reader can reserve space.
 213   TypeVals.push_back(TypeList.size());
 214   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 215   TypeVals.clear();
 216
 217   // Loop over all of the types, emitting each in turn.
 218   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 219     const Type *T = TypeList[i];
 220     int AbbrevToUse = 0;
 221     unsigned Code = 0;
 222
 223     switch (T->getTypeID()) {
 224     default: llvm_unreachable("Unknown type!");
 225     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
 226     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
 227     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
 228     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
 229     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128; break;
 230     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 231     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;  break;
 232     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA; break;
 233     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX; break;
 234     case Type::IntegerTyID:
 235       // INTEGER: [width]
 236       Code = bitc::TYPE_CODE_INTEGER;
 237       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 238       break;
 239     case Type::PointerTyID: {
 240       const PointerType *PTy = cast<PointerType>(T);
 241       // POINTER: [pointee type, address space]
 242       Code = bitc::TYPE_CODE_POINTER;
 243       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 244       unsigned AddressSpace = PTy->getAddressSpace();
 245       TypeVals.push_back(AddressSpace);
 246       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 247       break;
 248     }
 249     case Type::FunctionTyID: {
 250       const FunctionType *FT = cast<FunctionType>(T);
 251       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 252       Code = bitc::TYPE_CODE_FUNCTION;
 253       TypeVals.push_back(FT->isVarArg());
 254       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 255       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 256       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 257         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 258       AbbrevToUse = FunctionAbbrev;
 259       break;
 260     }
 261     case Type::StructTyID: {
 262       const StructType *ST = cast<StructType>(T);
 263       // STRUCT: [ispacked, eltty x N]
 264       TypeVals.push_back(ST->isPacked());
 265       // Output all of the element types.
 266       for (StructType::element_iterator I = ST->element_begin(),
 267            E = ST->element_end(); I != E; ++I)
 268         TypeVals.push_back(VE.getTypeID(*I));
 269
 270       if (ST->isAnonymous()) {
 271         Code = bitc::TYPE_CODE_STRUCT_ANON;
 272         AbbrevToUse = StructAnonAbbrev;
 273       } else {
 274         if (ST->isOpaque()) {
 275           Code = bitc::TYPE_CODE_OPAQUE;
 276         } else {
 277           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 278           AbbrevToUse = StructNamedAbbrev;
 279         }
 280
 281         // Emit the name if it is present.
 282         if (!ST->getName().empty())
 283           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 284                             StructNameAbbrev, Stream);
 285       }
 286       break;
 287     }
 288     case Type::ArrayTyID: {
 289       const ArrayType *AT = cast<ArrayType>(T);
 290       // ARRAY: [numelts, eltty]
 291       Code = bitc::TYPE_CODE_ARRAY;
 292       TypeVals.push_back(AT->getNumElements());
 293       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 294       AbbrevToUse = ArrayAbbrev;
 295       break;
 296     }
 297     case Type::VectorTyID: {
 298       const VectorType *VT = cast<VectorType>(T);
 299       // VECTOR [numelts, eltty]
 300       Code = bitc::TYPE_CODE_VECTOR;
 301       TypeVals.push_back(VT->getNumElements());
 302       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 303       break;
 304     }
 305     }
 306
 307     // Emit the finished record.
 308     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 309     TypeVals.clear();
 310   }
 311
 312   Stream.ExitBlock();
 313 }
 314
 315 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 316   switch (GV->getLinkage()) {
 317   default: llvm_unreachable("Invalid linkage!");
 318   case GlobalValue::ExternalLinkage:                 return 0;
 319   case GlobalValue::WeakAnyLinkage:                  return 1;
 320   case GlobalValue::AppendingLinkage:                return 2;
 321   case GlobalValue::InternalLinkage:                 return 3;
 322   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 323   case GlobalValue::DLLImportLinkage:                return 5;
 324   case GlobalValue::DLLExportLinkage:                return 6;
 325   case GlobalValue::ExternalWeakLinkage:             return 7;
 326   case GlobalValue::CommonLinkage:                   return 8;
 327   case GlobalValue::PrivateLinkage:                  return 9;
 328   case GlobalValue::WeakODRLinkage:                  return 10;
 329   case GlobalValue::LinkOnceODRLinkage:              return 11;
 330   case GlobalValue::AvailableExternallyLinkage:      return 12;
 331   case GlobalValue::LinkerPrivateLinkage:            return 13;
 332   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 333   case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
 334   }
 335 }
 336
 337 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 338   switch (GV->getVisibility()) {
 339   default: llvm_unreachable("Invalid visibility!");
 340   case GlobalValue::DefaultVisibility:   return 0;
 341   case GlobalValue::HiddenVisibility:    return 1;
 342   case GlobalValue::ProtectedVisibility: return 2;
 343   }
 344 }
 345
 346 // Emit top-level description of module, including target triple, inline asm,
 347 // descriptors for global variables, and function prototype info.
 348 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 349                             BitstreamWriter &Stream) {
 350   // Emit the list of dependent libraries for the Module.
 351   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 352     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 353
 354   // Emit various pieces of data attached to a module.
 355   if (!M->getTargetTriple().empty())
 356     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 357                       0/*TODO*/, Stream);
 358   if (!M->getDataLayout().empty())
 359     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 360                       0/*TODO*/, Stream);
 361   if (!M->getModuleInlineAsm().empty())
 362     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 363                       0/*TODO*/, Stream);
 364
 365   // Emit information about sections and GC, computing how many there are. Also
 366   // compute the maximum alignment value.
 367   std::map<std::string, unsigned> SectionMap;
 368   std::map<std::string, unsigned> GCMap;
 369   unsigned MaxAlignment = 0;
 370   unsigned MaxGlobalType = 0;
 371   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 372        GV != E; ++GV) {
 373     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 374     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 375
 376     if (!GV->hasSection()) continue;
 377     // Give section names unique ID's.
 378     unsigned &Entry = SectionMap[GV->getSection()];
 379     if (Entry != 0) continue;
 380     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 381                       0/*TODO*/, Stream);
 382     Entry = SectionMap.size();
 383   }
 384   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 385     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 386     if (F->hasSection()) {
 387       // Give section names unique ID's.
 388       unsigned &Entry = SectionMap[F->getSection()];
 389       if (!Entry) {
 390         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 391                           0/*TODO*/, Stream);
 392         Entry = SectionMap.size();
 393       }
 394     }
 395     if (F->hasGC()) {
 396       // Same for GC names.
 397       unsigned &Entry = GCMap[F->getGC()];
 398       if (!Entry) {
 399         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 400                           0/*TODO*/, Stream);
 401         Entry = GCMap.size();
 402       }
 403     }
 404   }
 405
 406   // Emit abbrev for globals, now that we know # sections and max alignment.
 407   unsigned SimpleGVarAbbrev = 0;
 408   if (!M->global_empty()) {
 409     // Add an abbrev for common globals with no visibility or thread localness.
 410     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 411     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 413                               Log2_32_Ceil(MaxGlobalType+1)));
 414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 417     if (MaxAlignment == 0)                                      // Alignment.
 418       Abbv->Add(BitCodeAbbrevOp(0));
 419     else {
 420       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 421       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 422                                Log2_32_Ceil(MaxEncAlignment+1)));
 423     }
 424     if (SectionMap.empty())                                    // Section.
 425       Abbv->Add(BitCodeAbbrevOp(0));
 426     else
 427       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 428                                Log2_32_Ceil(SectionMap.size()+1)));
 429     // Don't bother emitting vis + thread local.
 430     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 431   }
 432
 433   // Emit the global variable information.
 434   SmallVector<unsigned, 64> Vals;
 435   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 436        GV != E; ++GV) {
 437     unsigned AbbrevToUse = 0;
 438
 439     // GLOBALVAR: [type, isconst, initid,
 440     //             linkage, alignment, section, visibility, threadlocal,
 441     //             unnamed_addr]
 442     Vals.push_back(VE.getTypeID(GV->getType()));
 443     Vals.push_back(GV->isConstant());
 444     Vals.push_back(GV->isDeclaration() ? 0 :
 445                    (VE.getValueID(GV->getInitializer()) + 1));
 446     Vals.push_back(getEncodedLinkage(GV));
 447     Vals.push_back(Log2_32(GV->getAlignment())+1);
 448     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 449     if (GV->isThreadLocal() ||
 450         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 451         GV->hasUnnamedAddr()) {
 452       Vals.push_back(getEncodedVisibility(GV));
 453       Vals.push_back(GV->isThreadLocal());
 454       Vals.push_back(GV->hasUnnamedAddr());
 455     } else {
 456       AbbrevToUse = SimpleGVarAbbrev;
 457     }
 458
 459     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 460     Vals.clear();
 461   }
 462
 463   // Emit the function proto information.
 464   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 465     // FUNCTION:  [type, callingconv, isproto, paramattr,
 466     //             linkage, alignment, section, visibility, gc, unnamed_addr]
 467     Vals.push_back(VE.getTypeID(F->getType()));
 468     Vals.push_back(F->getCallingConv());
 469     Vals.push_back(F->isDeclaration());
 470     Vals.push_back(getEncodedLinkage(F));
 471     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 472     Vals.push_back(Log2_32(F->getAlignment())+1);
 473     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 474     Vals.push_back(getEncodedVisibility(F));
 475     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 476     Vals.push_back(F->hasUnnamedAddr());
 477
 478     unsigned AbbrevToUse = 0;
 479     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 480     Vals.clear();
 481   }
 482
 483   // Emit the alias information.
 484   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 485        AI != E; ++AI) {
 486     Vals.push_back(VE.getTypeID(AI->getType()));
 487     Vals.push_back(VE.getValueID(AI->getAliasee()));
 488     Vals.push_back(getEncodedLinkage(AI));
 489     Vals.push_back(getEncodedVisibility(AI));
 490     unsigned AbbrevToUse = 0;
 491     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 492     Vals.clear();
 493   }
 494 }
 495
 496 static uint64_t GetOptimizationFlags(const Value *V) {
 497   uint64_t Flags = 0;
 498
 499   if (const OverflowingBinaryOperator *OBO =
 500         dyn_cast<OverflowingBinaryOperator>(V)) {
 501     if (OBO->hasNoSignedWrap())
 502       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 503     if (OBO->hasNoUnsignedWrap())
 504       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 505   } else if (const PossiblyExactOperator *PEO =
 506                dyn_cast<PossiblyExactOperator>(V)) {
 507     if (PEO->isExact())
 508       Flags |= 1 << bitc::PEO_EXACT;
 509   }
 510
 511   return Flags;
 512 }
 513
 514 static void WriteMDNode(const MDNode *N,
 515                         const ValueEnumerator &VE,
 516                         BitstreamWriter &Stream,
 517                         SmallVector<uint64_t, 64> &Record) {
 518   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 519     if (N->getOperand(i)) {
 520       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 521       Record.push_back(VE.getValueID(N->getOperand(i)));
 522     } else {
 523       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 524       Record.push_back(0);
 525     }
 526   }
 527   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 528                                            bitc::METADATA_NODE;
 529   Stream.EmitRecord(MDCode, Record, 0);
 530   Record.clear();
 531 }
 532
 533 static void WriteModuleMetadata(const Module *M,
 534                                 const ValueEnumerator &VE,
 535                                 BitstreamWriter &Stream) {
 536   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 537   bool StartedMetadataBlock = false;
 538   unsigned MDSAbbrev = 0;
 539   SmallVector<uint64_t, 64> Record;
 540   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 541
 542     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 543       if (!N->isFunctionLocal() || !N->getFunction()) {
 544         if (!StartedMetadataBlock) {
 545           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 546           StartedMetadataBlock = true;
 547         }
 548         WriteMDNode(N, VE, Stream, Record);
 549       }
 550     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 551       if (!StartedMetadataBlock)  {
 552         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 553
 554         // Abbrev for METADATA_STRING.
 555         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 556         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 557         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 558         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 559         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 560         StartedMetadataBlock = true;
 561       }
 562
 563       // Code: [strchar x N]
 564       Record.append(MDS->begin(), MDS->end());
 565
 566       // Emit the finished record.
 567       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 568       Record.clear();
 569     }
 570   }
 571
 572   // Write named metadata.
 573   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 574        E = M->named_metadata_end(); I != E; ++I) {
 575     const NamedMDNode *NMD = I;
 576     if (!StartedMetadataBlock)  {
 577       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 578       StartedMetadataBlock = true;
 579     }
 580
 581     // Write name.
 582     StringRef Str = NMD->getName();
 583     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 584       Record.push_back(Str[i]);
 585     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 586     Record.clear();
 587
 588     // Write named metadata operands.
 589     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 590       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 591     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 592     Record.clear();
 593   }
 594
 595   if (StartedMetadataBlock)
 596     Stream.ExitBlock();
 597 }
 598
 599 static void WriteFunctionLocalMetadata(const Function &F,
 600                                        const ValueEnumerator &VE,
 601                                        BitstreamWriter &Stream) {
 602   bool StartedMetadataBlock = false;
 603   SmallVector<uint64_t, 64> Record;
 604   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
 605   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 606     if (const MDNode *N = Vals[i])
 607       if (N->isFunctionLocal() && N->getFunction() == &F) {
 608         if (!StartedMetadataBlock) {
 609           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 610           StartedMetadataBlock = true;
 611         }
 612         WriteMDNode(N, VE, Stream, Record);
 613       }
 614
 615   if (StartedMetadataBlock)
 616     Stream.ExitBlock();
 617 }
 618
 619 static void WriteMetadataAttachment(const Function &F,
 620                                     const ValueEnumerator &VE,
 621                                     BitstreamWriter &Stream) {
 622   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 623
 624   SmallVector<uint64_t, 64> Record;
 625
 626   // Write metadata attachments
 627   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 628   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 629
 630   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 631     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 632          I != E; ++I) {
 633       MDs.clear();
 634       I->getAllMetadataOtherThanDebugLoc(MDs);
 635
 636       // If no metadata, ignore instruction.
 637       if (MDs.empty()) continue;
 638
 639       Record.push_back(VE.getInstructionID(I));
 640
 641       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 642         Record.push_back(MDs[i].first);
 643         Record.push_back(VE.getValueID(MDs[i].second));
 644       }
 645       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 646       Record.clear();
 647     }
 648
 649   Stream.ExitBlock();
 650 }
 651
 652 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 653   SmallVector<uint64_t, 64> Record;
 654
 655   // Write metadata kinds
 656   // METADATA_KIND - [n x [id, name]]
 657   SmallVector<StringRef, 4> Names;
 658   M->getMDKindNames(Names);
 659
 660   if (Names.empty()) return;
 661
 662   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 663
 664   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 665     Record.push_back(MDKindID);
 666     StringRef KName = Names[MDKindID];
 667     Record.append(KName.begin(), KName.end());
 668
 669     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 670     Record.clear();
 671   }
 672
 673   Stream.ExitBlock();
 674 }
 675
 676 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 677                            const ValueEnumerator &VE,
 678                            BitstreamWriter &Stream, bool isGlobal) {
 679   if (FirstVal == LastVal) return;
 680
 681   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 682
 683   unsigned AggregateAbbrev = 0;
 684   unsigned String8Abbrev = 0;
 685   unsigned CString7Abbrev = 0;
 686   unsigned CString6Abbrev = 0;
 687   // If this is a constant pool for the module, emit module-specific abbrevs.
 688   if (isGlobal) {
 689     // Abbrev for CST_CODE_AGGREGATE.
 690     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 691     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 692     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 693     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 694     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 695
 696     // Abbrev for CST_CODE_STRING.
 697     Abbv = new BitCodeAbbrev();
 698     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 699     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 700     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 701     String8Abbrev = Stream.EmitAbbrev(Abbv);
 702     // Abbrev for CST_CODE_CSTRING.
 703     Abbv = new BitCodeAbbrev();
 704     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 705     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 706     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 707     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 708     // Abbrev for CST_CODE_CSTRING.
 709     Abbv = new BitCodeAbbrev();
 710     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 711     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 712     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 713     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 714   }
 715
 716   SmallVector<uint64_t, 64> Record;
 717
 718   const ValueEnumerator::ValueList &Vals = VE.getValues();
 719   const Type *LastTy = 0;
 720   for (unsigned i = FirstVal; i != LastVal; ++i) {
 721     const Value *V = Vals[i].first;
 722     // If we need to switch types, do so now.
 723     if (V->getType() != LastTy) {
 724       LastTy = V->getType();
 725       Record.push_back(VE.getTypeID(LastTy));
 726       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 727                         CONSTANTS_SETTYPE_ABBREV);
 728       Record.clear();
 729     }
 730
 731     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 732       Record.push_back(unsigned(IA->hasSideEffects()) |
 733                        unsigned(IA->isAlignStack()) << 1);
 734
 735       // Add the asm string.
 736       const std::string &AsmStr = IA->getAsmString();
 737       Record.push_back(AsmStr.size());
 738       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 739         Record.push_back(AsmStr[i]);
 740
 741       // Add the constraint string.
 742       const std::string &ConstraintStr = IA->getConstraintString();
 743       Record.push_back(ConstraintStr.size());
 744       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 745         Record.push_back(ConstraintStr[i]);
 746       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 747       Record.clear();
 748       continue;
 749     }
 750     const Constant *C = cast<Constant>(V);
 751     unsigned Code = -1U;
 752     unsigned AbbrevToUse = 0;
 753     if (C->isNullValue()) {
 754       Code = bitc::CST_CODE_NULL;
 755     } else if (isa<UndefValue>(C)) {
 756       Code = bitc::CST_CODE_UNDEF;
 757     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 758       if (IV->getBitWidth() <= 64) {
 759         uint64_t V = IV->getSExtValue();
 760         if ((int64_t)V >= 0)
 761           Record.push_back(V << 1);
 762         else
 763           Record.push_back((-V << 1) | 1);
 764         Code = bitc::CST_CODE_INTEGER;
 765         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 766       } else {                             // Wide integers, > 64 bits in size.
 767         // We have an arbitrary precision integer value to write whose
 768         // bit width is > 64. However, in canonical unsigned integer
 769         // format it is likely that the high bits are going to be zero.
 770         // So, we only write the number of active words.
 771         unsigned NWords = IV->getValue().getActiveWords();
 772         const uint64_t *RawWords = IV->getValue().getRawData();
 773         for (unsigned i = 0; i != NWords; ++i) {
 774           int64_t V = RawWords[i];
 775           if (V >= 0)
 776             Record.push_back(V << 1);
 777           else
 778             Record.push_back((-V << 1) | 1);
 779         }
 780         Code = bitc::CST_CODE_WIDE_INTEGER;
 781       }
 782     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 783       Code = bitc::CST_CODE_FLOAT;
 784       const Type *Ty = CFP->getType();
 785       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 786         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 787       } else if (Ty->isX86_FP80Ty()) {
 788         // api needed to prevent premature destruction
 789         // bits are not in the same order as a normal i80 APInt, compensate.
 790         APInt api = CFP->getValueAPF().bitcastToAPInt();
 791         const uint64_t *p = api.getRawData();
 792         Record.push_back((p[1] << 48) | (p[0] >> 16));
 793         Record.push_back(p[0] & 0xffffLL);
 794       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 795         APInt api = CFP->getValueAPF().bitcastToAPInt();
 796         const uint64_t *p = api.getRawData();
 797         Record.push_back(p[0]);
 798         Record.push_back(p[1]);
 799       } else {
 800         assert (0 && "Unknown FP type!");
 801       }
 802     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 803       const ConstantArray *CA = cast<ConstantArray>(C);
 804       // Emit constant strings specially.
 805       unsigned NumOps = CA->getNumOperands();
 806       // If this is a null-terminated string, use the denser CSTRING encoding.
 807       if (CA->getOperand(NumOps-1)->isNullValue()) {
 808         Code = bitc::CST_CODE_CSTRING;
 809         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 810       } else {
 811         Code = bitc::CST_CODE_STRING;
 812         AbbrevToUse = String8Abbrev;
 813       }
 814       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 815       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 816       for (unsigned i = 0; i != NumOps; ++i) {
 817         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 818         Record.push_back(V);
 819         isCStr7 &= (V & 128) == 0;
 820         if (isCStrChar6)
 821           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 822       }
 823
 824       if (isCStrChar6)
 825         AbbrevToUse = CString6Abbrev;
 826       else if (isCStr7)
 827         AbbrevToUse = CString7Abbrev;
 828     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 829                isa<ConstantVector>(V)) {
 830       Code = bitc::CST_CODE_AGGREGATE;
 831       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 832         Record.push_back(VE.getValueID(C->getOperand(i)));
 833       AbbrevToUse = AggregateAbbrev;
 834     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 835       switch (CE->getOpcode()) {
 836       default:
 837         if (Instruction::isCast(CE->getOpcode())) {
 838           Code = bitc::CST_CODE_CE_CAST;
 839           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 840           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 841           Record.push_back(VE.getValueID(C->getOperand(0)));
 842           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 843         } else {
 844           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 845           Code = bitc::CST_CODE_CE_BINOP;
 846           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 847           Record.push_back(VE.getValueID(C->getOperand(0)));
 848           Record.push_back(VE.getValueID(C->getOperand(1)));
 849           uint64_t Flags = GetOptimizationFlags(CE);
 850           if (Flags != 0)
 851             Record.push_back(Flags);
 852         }
 853         break;
 854       case Instruction::GetElementPtr:
 855         Code = bitc::CST_CODE_CE_GEP;
 856         if (cast<GEPOperator>(C)->isInBounds())
 857           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 858         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 859           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 860           Record.push_back(VE.getValueID(C->getOperand(i)));
 861         }
 862         break;
 863       case Instruction::Select:
 864         Code = bitc::CST_CODE_CE_SELECT;
 865         Record.push_back(VE.getValueID(C->getOperand(0)));
 866         Record.push_back(VE.getValueID(C->getOperand(1)));
 867         Record.push_back(VE.getValueID(C->getOperand(2)));
 868         break;
 869       case Instruction::ExtractElement:
 870         Code = bitc::CST_CODE_CE_EXTRACTELT;
 871         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 872         Record.push_back(VE.getValueID(C->getOperand(0)));
 873         Record.push_back(VE.getValueID(C->getOperand(1)));
 874         break;
 875       case Instruction::InsertElement:
 876         Code = bitc::CST_CODE_CE_INSERTELT;
 877         Record.push_back(VE.getValueID(C->getOperand(0)));
 878         Record.push_back(VE.getValueID(C->getOperand(1)));
 879         Record.push_back(VE.getValueID(C->getOperand(2)));
 880         break;
 881       case Instruction::ShuffleVector:
 882         // If the return type and argument types are the same, this is a
 883         // standard shufflevector instruction.  If the types are different,
 884         // then the shuffle is widening or truncating the input vectors, and
 885         // the argument type must also be encoded.
 886         if (C->getType() == C->getOperand(0)->getType()) {
 887           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 888         } else {
 889           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 890           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 891         }
 892         Record.push_back(VE.getValueID(C->getOperand(0)));
 893         Record.push_back(VE.getValueID(C->getOperand(1)));
 894         Record.push_back(VE.getValueID(C->getOperand(2)));
 895         break;
 896       case Instruction::ICmp:
 897       case Instruction::FCmp:
 898         Code = bitc::CST_CODE_CE_CMP;
 899         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 900         Record.push_back(VE.getValueID(C->getOperand(0)));
 901         Record.push_back(VE.getValueID(C->getOperand(1)));
 902         Record.push_back(CE->getPredicate());
 903         break;
 904       }
 905     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 906       Code = bitc::CST_CODE_BLOCKADDRESS;
 907       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 908       Record.push_back(VE.getValueID(BA->getFunction()));
 909       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 910     } else {
 911 #ifndef NDEBUG
 912       C->dump();
 913 #endif
 914       llvm_unreachable("Unknown constant!");
 915     }
 916     Stream.EmitRecord(Code, Record, AbbrevToUse);
 917     Record.clear();
 918   }
 919
 920   Stream.ExitBlock();
 921 }
 922
 923 static void WriteModuleConstants(const ValueEnumerator &VE,
 924                                  BitstreamWriter &Stream) {
 925   const ValueEnumerator::ValueList &Vals = VE.getValues();
 926
 927   // Find the first constant to emit, which is the first non-globalvalue value.
 928   // We know globalvalues have been emitted by WriteModuleInfo.
 929   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 930     if (!isa<GlobalValue>(Vals[i].first)) {
 931       WriteConstants(i, Vals.size(), VE, Stream, true);
 932       return;
 933     }
 934   }
 935 }
 936
 937 /// PushValueAndType - The file has to encode both the value and type id for
 938 /// many values, because we need to know what type to create for forward
 939 /// references.  However, most operands are not forward references, so this type
 940 /// field is not needed.
 941 ///
 942 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 943 /// instruction ID, then it is a forward reference, and it also includes the
 944 /// type ID.
 945 static bool PushValueAndType(const Value *V, unsigned InstID,
 946                              SmallVector<unsigned, 64> &Vals,
 947                              ValueEnumerator &VE) {
 948   unsigned ValID = VE.getValueID(V);
 949   Vals.push_back(ValID);
 950   if (ValID >= InstID) {
 951     Vals.push_back(VE.getTypeID(V->getType()));
 952     return true;
 953   }
 954   return false;
 955 }
 956
 957 /// WriteInstruction - Emit an instruction to the specified stream.
 958 static void WriteInstruction(const Instruction &I, unsigned InstID,
 959                              ValueEnumerator &VE, BitstreamWriter &Stream,
 960                              SmallVector<unsigned, 64> &Vals) {
 961   unsigned Code = 0;
 962   unsigned AbbrevToUse = 0;
 963   VE.setInstructionID(&I);
 964   switch (I.getOpcode()) {
 965   default:
 966     if (Instruction::isCast(I.getOpcode())) {
 967       Code = bitc::FUNC_CODE_INST_CAST;
 968       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 969         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 970       Vals.push_back(VE.getTypeID(I.getType()));
 971       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 972     } else {
 973       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 974       Code = bitc::FUNC_CODE_INST_BINOP;
 975       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 976         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 977       Vals.push_back(VE.getValueID(I.getOperand(1)));
 978       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 979       uint64_t Flags = GetOptimizationFlags(&I);
 980       if (Flags != 0) {
 981         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 982           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 983         Vals.push_back(Flags);
 984       }
 985     }
 986     break;
 987
 988   case Instruction::GetElementPtr:
 989     Code = bitc::FUNC_CODE_INST_GEP;
 990     if (cast<GEPOperator>(&I)->isInBounds())
 991       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 992     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 993       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 994     break;
 995   case Instruction::ExtractValue: {
 996     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 997     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 998     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 999     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1000       Vals.push_back(*i);
1001     break;
1002   }
1003   case Instruction::InsertValue: {
1004     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1005     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1006     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1007     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1008     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1009       Vals.push_back(*i);
1010     break;
1011   }
1012   case Instruction::Select:
1013     Code = bitc::FUNC_CODE_INST_VSELECT;
1014     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1015     Vals.push_back(VE.getValueID(I.getOperand(2)));
1016     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1017     break;
1018   case Instruction::ExtractElement:
1019     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1020     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1021     Vals.push_back(VE.getValueID(I.getOperand(1)));
1022     break;
1023   case Instruction::InsertElement:
1024     Code = bitc::FUNC_CODE_INST_INSERTELT;
1025     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1026     Vals.push_back(VE.getValueID(I.getOperand(1)));
1027     Vals.push_back(VE.getValueID(I.getOperand(2)));
1028     break;
1029   case Instruction::ShuffleVector:
1030     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1031     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1032     Vals.push_back(VE.getValueID(I.getOperand(1)));
1033     Vals.push_back(VE.getValueID(I.getOperand(2)));
1034     break;
1035   case Instruction::ICmp:
1036   case Instruction::FCmp:
1037     // compare returning Int1Ty or vector of Int1Ty
1038     Code = bitc::FUNC_CODE_INST_CMP2;
1039     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1040     Vals.push_back(VE.getValueID(I.getOperand(1)));
1041     Vals.push_back(cast<CmpInst>(I).getPredicate());
1042     break;
1043
1044   case Instruction::Ret:
1045     {
1046       Code = bitc::FUNC_CODE_INST_RET;
1047       unsigned NumOperands = I.getNumOperands();
1048       if (NumOperands == 0)
1049         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1050       else if (NumOperands == 1) {
1051         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1052           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1053       } else {
1054         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1055           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1056       }
1057     }
1058     break;
1059   case Instruction::Br:
1060     {
1061       Code = bitc::FUNC_CODE_INST_BR;
1062       BranchInst &II = cast<BranchInst>(I);
1063       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1064       if (II.isConditional()) {
1065         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1066         Vals.push_back(VE.getValueID(II.getCondition()));
1067       }
1068     }
1069     break;
1070   case Instruction::Switch:
1071     Code = bitc::FUNC_CODE_INST_SWITCH;
1072     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1073     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1074       Vals.push_back(VE.getValueID(I.getOperand(i)));
1075     break;
1076   case Instruction::IndirectBr:
1077     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1078     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1079     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1080       Vals.push_back(VE.getValueID(I.getOperand(i)));
1081     break;
1082
1083   case Instruction::Invoke: {
1084     const InvokeInst *II = cast<InvokeInst>(&I);
1085     const Value *Callee(II->getCalledValue());
1086     const PointerType *PTy = cast<PointerType>(Callee->getType());
1087     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1088     Code = bitc::FUNC_CODE_INST_INVOKE;
1089
1090     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1091     Vals.push_back(II->getCallingConv());
1092     Vals.push_back(VE.getValueID(II->getNormalDest()));
1093     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1094     PushValueAndType(Callee, InstID, Vals, VE);
1095
1096     // Emit value #'s for the fixed parameters.
1097     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1098       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1099
1100     // Emit type/value pairs for varargs params.
1101     if (FTy->isVarArg()) {
1102       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1103            i != e; ++i)
1104         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1105     }
1106     break;
1107   }
1108   case Instruction::Unwind:
1109     Code = bitc::FUNC_CODE_INST_UNWIND;
1110     break;
1111   case Instruction::Unreachable:
1112     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1113     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1114     break;
1115
1116   case Instruction::PHI: {
1117     const PHINode &PN = cast<PHINode>(I);
1118     Code = bitc::FUNC_CODE_INST_PHI;
1119     Vals.push_back(VE.getTypeID(PN.getType()));
1120     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1121       Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1122       Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1123     }
1124     break;
1125   }
1126
1127   case Instruction::Alloca:
1128     Code = bitc::FUNC_CODE_INST_ALLOCA;
1129     Vals.push_back(VE.getTypeID(I.getType()));
1130     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1131     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1132     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1133     break;
1134
1135   case Instruction::Load:
1136     Code = bitc::FUNC_CODE_INST_LOAD;
1137     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1138       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1139
1140     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1141     Vals.push_back(cast<LoadInst>(I).isVolatile());
1142     break;
1143   case Instruction::Store:
1144     Code = bitc::FUNC_CODE_INST_STORE;
1145     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1146     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1147     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1148     Vals.push_back(cast<StoreInst>(I).isVolatile());
1149     break;
1150   case Instruction::Call: {
1151     const CallInst &CI = cast<CallInst>(I);
1152     const PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1153     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1154
1155     Code = bitc::FUNC_CODE_INST_CALL;
1156
1157     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1158     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1159     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1160
1161     // Emit value #'s for the fixed parameters.
1162     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1163       Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1164
1165     // Emit type/value pairs for varargs params.
1166     if (FTy->isVarArg()) {
1167       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1168            i != e; ++i)
1169         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1170     }
1171     break;
1172   }
1173   case Instruction::VAArg:
1174     Code = bitc::FUNC_CODE_INST_VAARG;
1175     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1176     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1177     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1178     break;
1179   }
1180
1181   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1182   Vals.clear();
1183 }
1184
1185 // Emit names for globals/functions etc.
1186 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1187                                   const ValueEnumerator &VE,
1188                                   BitstreamWriter &Stream) {
1189   if (VST.empty()) return;
1190   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1191
1192   // FIXME: Set up the abbrev, we know how many values there are!
1193   // FIXME: We know if the type names can use 7-bit ascii.
1194   SmallVector<unsigned, 64> NameVals;
1195
1196   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1197        SI != SE; ++SI) {
1198
1199     const ValueName &Name = *SI;
1200
1201     // Figure out the encoding to use for the name.
1202     bool is7Bit = true;
1203     bool isChar6 = true;
1204     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1205          C != E; ++C) {
1206       if (isChar6)
1207         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1208       if ((unsigned char)*C & 128) {
1209         is7Bit = false;
1210         break;  // don't bother scanning the rest.
1211       }
1212     }
1213
1214     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1215
1216     // VST_ENTRY:   [valueid, namechar x N]
1217     // VST_BBENTRY: [bbid, namechar x N]
1218     unsigned Code;
1219     if (isa<BasicBlock>(SI->getValue())) {
1220       Code = bitc::VST_CODE_BBENTRY;
1221       if (isChar6)
1222         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1223     } else {
1224       Code = bitc::VST_CODE_ENTRY;
1225       if (isChar6)
1226         AbbrevToUse = VST_ENTRY_6_ABBREV;
1227       else if (is7Bit)
1228         AbbrevToUse = VST_ENTRY_7_ABBREV;
1229     }
1230
1231     NameVals.push_back(VE.getValueID(SI->getValue()));
1232     for (const char *P = Name.getKeyData(),
1233          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1234       NameVals.push_back((unsigned char)*P);
1235
1236     // Emit the finished record.
1237     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1238     NameVals.clear();
1239   }
1240   Stream.ExitBlock();
1241 }
1242
1243 /// WriteFunction - Emit a function body to the module stream.
1244 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1245                           BitstreamWriter &Stream) {
1246   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1247   VE.incorporateFunction(F);
1248
1249   SmallVector<unsigned, 64> Vals;
1250
1251   // Emit the number of basic blocks, so the reader can create them ahead of
1252   // time.
1253   Vals.push_back(VE.getBasicBlocks().size());
1254   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1255   Vals.clear();
1256
1257   // If there are function-local constants, emit them now.
1258   unsigned CstStart, CstEnd;
1259   VE.getFunctionConstantRange(CstStart, CstEnd);
1260   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1261
1262   // If there is function-local metadata, emit it now.
1263   WriteFunctionLocalMetadata(F, VE, Stream);
1264
1265   // Keep a running idea of what the instruction ID is.
1266   unsigned InstID = CstEnd;
1267
1268   bool NeedsMetadataAttachment = false;
1269
1270   DebugLoc LastDL;
1271
1272   // Finally, emit all the instructions, in order.
1273   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1274     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1275          I != E; ++I) {
1276       WriteInstruction(*I, InstID, VE, Stream, Vals);
1277
1278       if (!I->getType()->isVoidTy())
1279         ++InstID;
1280
1281       // If the instruction has metadata, write a metadata attachment later.
1282       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1283
1284       // If the instruction has a debug location, emit it.
1285       DebugLoc DL = I->getDebugLoc();
1286       if (DL.isUnknown()) {
1287         // nothing todo.
1288       } else if (DL == LastDL) {
1289         // Just repeat the same debug loc as last time.
1290         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1291       } else {
1292         MDNode *Scope, *IA;
1293         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1294
1295         Vals.push_back(DL.getLine());
1296         Vals.push_back(DL.getCol());
1297         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1298         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1299         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1300         Vals.clear();
1301
1302         LastDL = DL;
1303       }
1304     }
1305
1306   // Emit names for all the instructions etc.
1307   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1308
1309   if (NeedsMetadataAttachment)
1310     WriteMetadataAttachment(F, VE, Stream);
1311   VE.purgeFunction();
1312   Stream.ExitBlock();
1313 }
1314
1315 // Emit blockinfo, which defines the standard abbreviations etc.
1316 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1317   // We only want to emit block info records for blocks that have multiple
1318   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1319   // blocks can defined their abbrevs inline.
1320   Stream.EnterBlockInfoBlock(2);
1321
1322   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1323     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1324     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1325     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1328     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1329                                    Abbv) != VST_ENTRY_8_ABBREV)
1330       llvm_unreachable("Unexpected abbrev ordering!");
1331   }
1332
1333   { // 7-bit fixed width VST_ENTRY strings.
1334     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1335     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1336     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1337     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1339     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1340                                    Abbv) != VST_ENTRY_7_ABBREV)
1341       llvm_unreachable("Unexpected abbrev ordering!");
1342   }
1343   { // 6-bit char6 VST_ENTRY strings.
1344     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1345     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1346     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1349     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1350                                    Abbv) != VST_ENTRY_6_ABBREV)
1351       llvm_unreachable("Unexpected abbrev ordering!");
1352   }
1353   { // 6-bit char6 VST_BBENTRY strings.
1354     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1355     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1356     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1359     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1360                                    Abbv) != VST_BBENTRY_6_ABBREV)
1361       llvm_unreachable("Unexpected abbrev ordering!");
1362   }
1363
1364
1365
1366   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1367     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1368     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1370                               Log2_32_Ceil(VE.getTypes().size()+1)));
1371     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1372                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1373       llvm_unreachable("Unexpected abbrev ordering!");
1374   }
1375
1376   { // INTEGER abbrev for CONSTANTS_BLOCK.
1377     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1378     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1380     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1381                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1382       llvm_unreachable("Unexpected abbrev ordering!");
1383   }
1384
1385   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1386     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1387     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1390                               Log2_32_Ceil(VE.getTypes().size()+1)));
1391     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1392
1393     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1394                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1395       llvm_unreachable("Unexpected abbrev ordering!");
1396   }
1397   { // NULL abbrev for CONSTANTS_BLOCK.
1398     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1399     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1400     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1401                                    Abbv) != CONSTANTS_NULL_Abbrev)
1402       llvm_unreachable("Unexpected abbrev ordering!");
1403   }
1404
1405   // FIXME: This should only use space for first class types!
1406
1407   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1408     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1409     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1411     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1413     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1414                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1415       llvm_unreachable("Unexpected abbrev ordering!");
1416   }
1417   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1418     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1419     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1422     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1423     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1424                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1425       llvm_unreachable("Unexpected abbrev ordering!");
1426   }
1427   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1428     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1429     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1434     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1435                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1436       llvm_unreachable("Unexpected abbrev ordering!");
1437   }
1438   { // INST_CAST abbrev for FUNCTION_BLOCK.
1439     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1440     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1443                               Log2_32_Ceil(VE.getTypes().size()+1)));
1444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1445     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1446                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1447       llvm_unreachable("Unexpected abbrev ordering!");
1448   }
1449
1450   { // INST_RET abbrev for FUNCTION_BLOCK.
1451     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1452     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1453     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1454                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1455       llvm_unreachable("Unexpected abbrev ordering!");
1456   }
1457   { // INST_RET abbrev for FUNCTION_BLOCK.
1458     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1459     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1461     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1462                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1463       llvm_unreachable("Unexpected abbrev ordering!");
1464   }
1465   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1466     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1467     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1468     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1469                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1470       llvm_unreachable("Unexpected abbrev ordering!");
1471   }
1472
1473   Stream.ExitBlock();
1474 }
1475
1476
1477 /// WriteModule - Emit the specified module to the bitstream.
1478 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1479   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1480
1481   // Emit the version number if it is non-zero.
1482   if (CurVersion) {
1483     SmallVector<unsigned, 1> Vals;
1484     Vals.push_back(CurVersion);
1485     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1486   }
1487
1488   // Analyze the module, enumerating globals, functions, etc.
1489   ValueEnumerator VE(M);
1490
1491   // Emit blockinfo, which defines the standard abbreviations etc.
1492   WriteBlockInfo(VE, Stream);
1493
1494   // Emit information about parameter attributes.
1495   WriteAttributeTable(VE, Stream);
1496
1497   // Emit information describing all of the types in the module.
1498   WriteTypeTable(VE, Stream);
1499
1500   // Emit top-level description of module, including target triple, inline asm,
1501   // descriptors for global variables, and function prototype info.
1502   WriteModuleInfo(M, VE, Stream);
1503
1504   // Emit constants.
1505   WriteModuleConstants(VE, Stream);
1506
1507   // Emit metadata.
1508   WriteModuleMetadata(M, VE, Stream);
1509
1510   // Emit function bodies.
1511   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1512     if (!F->isDeclaration())
1513       WriteFunction(*F, VE, Stream);
1514
1515   // Emit metadata.
1516   WriteModuleMetadataStore(M, Stream);
1517
1518   // Emit names for globals/functions etc.
1519   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1520
1521   Stream.ExitBlock();
1522 }
1523
1524 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1525 /// header and trailer to make it compatible with the system archiver.  To do
1526 /// this we emit the following header, and then emit a trailer that pads the
1527 /// file out to be a multiple of 16 bytes.
1528 ///
1529 /// struct bc_header {
1530 ///   uint32_t Magic;         // 0x0B17C0DE
1531 ///   uint32_t Version;       // Version, currently always 0.
1532 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1533 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1534 ///   uint32_t CPUType;       // CPU specifier.
1535 ///   ... potentially more later ...
1536 /// };
1537 enum {
1538   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1539   DarwinBCHeaderSize = 5*4
1540 };
1541
1542 static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
1543   unsigned CPUType = ~0U;
1544
1545   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1546   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1547   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1548   // specific constants here because they are implicitly part of the Darwin ABI.
1549   enum {
1550     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1551     DARWIN_CPU_TYPE_X86        = 7,
1552     DARWIN_CPU_TYPE_ARM        = 12,
1553     DARWIN_CPU_TYPE_POWERPC    = 18
1554   };
1555
1556   Triple::ArchType Arch = TT.getArch();
1557   if (Arch == Triple::x86_64)
1558     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1559   else if (Arch == Triple::x86)
1560     CPUType = DARWIN_CPU_TYPE_X86;
1561   else if (Arch == Triple::ppc)
1562     CPUType = DARWIN_CPU_TYPE_POWERPC;
1563   else if (Arch == Triple::ppc64)
1564     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1565   else if (Arch == Triple::arm || Arch == Triple::thumb)
1566     CPUType = DARWIN_CPU_TYPE_ARM;
1567
1568   // Traditional Bitcode starts after header.
1569   unsigned BCOffset = DarwinBCHeaderSize;
1570
1571   Stream.Emit(0x0B17C0DE, 32);
1572   Stream.Emit(0         , 32);  // Version.
1573   Stream.Emit(BCOffset  , 32);
1574   Stream.Emit(0         , 32);  // Filled in later.
1575   Stream.Emit(CPUType   , 32);
1576 }
1577
1578 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1579 /// finalize the header.
1580 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1581   // Update the size field in the header.
1582   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1583
1584   // If the file is not a multiple of 16 bytes, insert dummy padding.
1585   while (BufferSize & 15) {
1586     Stream.Emit(0, 8);
1587     ++BufferSize;
1588   }
1589 }
1590
1591
1592 /// WriteBitcodeToFile - Write the specified module to the specified output
1593 /// stream.
1594 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1595   std::vector<unsigned char> Buffer;
1596   BitstreamWriter Stream(Buffer);
1597
1598   Buffer.reserve(256*1024);
1599
1600   WriteBitcodeToStream( M, Stream );
1601
1602   // Write the generated bitstream to "Out".
1603   Out.write((char*)&Buffer.front(), Buffer.size());
1604 }
1605
1606 /// WriteBitcodeToStream - Write the specified module to the specified output
1607 /// stream.
1608 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1609   // If this is darwin or another generic macho target, emit a file header and
1610   // trailer if needed.
1611   Triple TT(M->getTargetTriple());
1612   if (TT.isOSDarwin())
1613     EmitDarwinBCHeader(Stream, TT);
1614
1615   // Emit the file header.
1616   Stream.Emit((unsigned)'B', 8);
1617   Stream.Emit((unsigned)'C', 8);
1618   Stream.Emit(0x0, 4);
1619   Stream.Emit(0xC, 4);
1620   Stream.Emit(0xE, 4);
1621   Stream.Emit(0xD, 4);
1622
1623   // Emit the module.
1624   WriteModule(M, Stream);
1625
1626   if (TT.isOSDarwin())
1627     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1628 }