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/Support/ErrorHandling.h"
  27 #include "llvm/Support/MathExtras.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include "llvm/System/Program.h"
  30 using namespace llvm;
  31
  32 /// These are manifest constants used by the bitcode writer. They do not need to
  33 /// be kept in sync with the reader, but need to be consistent within this file.
  34 enum {
  35   CurVersion = 0,
  36
  37   // VALUE_SYMTAB_BLOCK abbrev id's.
  38   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  39   VST_ENTRY_7_ABBREV,
  40   VST_ENTRY_6_ABBREV,
  41   VST_BBENTRY_6_ABBREV,
  42
  43   // CONSTANTS_BLOCK abbrev id's.
  44   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  45   CONSTANTS_INTEGER_ABBREV,
  46   CONSTANTS_CE_CAST_Abbrev,
  47   CONSTANTS_NULL_Abbrev,
  48
  49   // FUNCTION_BLOCK abbrev id's.
  50   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  51   FUNCTION_INST_BINOP_ABBREV,
  52   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  53   FUNCTION_INST_CAST_ABBREV,
  54   FUNCTION_INST_RET_VOID_ABBREV,
  55   FUNCTION_INST_RET_VAL_ABBREV,
  56   FUNCTION_INST_UNREACHABLE_ABBREV
  57 };
  58
  59
  60 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  61   switch (Opcode) {
  62   default: llvm_unreachable("Unknown cast instruction!");
  63   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  64   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  65   case Instruction::SExt    : return bitc::CAST_SEXT;
  66   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  67   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  68   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  69   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  70   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  71   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  72   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  73   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  74   case Instruction::BitCast : return bitc::CAST_BITCAST;
  75   }
  76 }
  77
  78 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  79   switch (Opcode) {
  80   default: llvm_unreachable("Unknown binary instruction!");
  81   case Instruction::Add:
  82   case Instruction::FAdd: return bitc::BINOP_ADD;
  83   case Instruction::Sub:
  84   case Instruction::FSub: return bitc::BINOP_SUB;
  85   case Instruction::Mul:
  86   case Instruction::FMul: return bitc::BINOP_MUL;
  87   case Instruction::UDiv: return bitc::BINOP_UDIV;
  88   case Instruction::FDiv:
  89   case Instruction::SDiv: return bitc::BINOP_SDIV;
  90   case Instruction::URem: return bitc::BINOP_UREM;
  91   case Instruction::FRem:
  92   case Instruction::SRem: return bitc::BINOP_SREM;
  93   case Instruction::Shl:  return bitc::BINOP_SHL;
  94   case Instruction::LShr: return bitc::BINOP_LSHR;
  95   case Instruction::AShr: return bitc::BINOP_ASHR;
  96   case Instruction::And:  return bitc::BINOP_AND;
  97   case Instruction::Or:   return bitc::BINOP_OR;
  98   case Instruction::Xor:  return bitc::BINOP_XOR;
  99   }
 100 }
 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].first;
 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::IntegerTyID:
 215       // INTEGER: [width]
 216       Code = bitc::TYPE_CODE_INTEGER;
 217       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 218       break;
 219     case Type::PointerTyID: {
 220       const PointerType *PTy = cast<PointerType>(T);
 221       // POINTER: [pointee type, address space]
 222       Code = bitc::TYPE_CODE_POINTER;
 223       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 224       unsigned AddressSpace = PTy->getAddressSpace();
 225       TypeVals.push_back(AddressSpace);
 226       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 227       break;
 228     }
 229     case Type::FunctionTyID: {
 230       const FunctionType *FT = cast<FunctionType>(T);
 231       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 232       Code = bitc::TYPE_CODE_FUNCTION;
 233       TypeVals.push_back(FT->isVarArg());
 234       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 235       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 236       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 237         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 238       AbbrevToUse = FunctionAbbrev;
 239       break;
 240     }
 241     case Type::StructTyID: {
 242       const StructType *ST = cast<StructType>(T);
 243       // STRUCT: [ispacked, eltty x N]
 244       Code = bitc::TYPE_CODE_STRUCT;
 245       TypeVals.push_back(ST->isPacked());
 246       // Output all of the element types.
 247       for (StructType::element_iterator I = ST->element_begin(),
 248            E = ST->element_end(); I != E; ++I)
 249         TypeVals.push_back(VE.getTypeID(*I));
 250       AbbrevToUse = StructAbbrev;
 251       break;
 252     }
 253     case Type::ArrayTyID: {
 254       const ArrayType *AT = cast<ArrayType>(T);
 255       // ARRAY: [numelts, eltty]
 256       Code = bitc::TYPE_CODE_ARRAY;
 257       TypeVals.push_back(AT->getNumElements());
 258       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 259       AbbrevToUse = ArrayAbbrev;
 260       break;
 261     }
 262     case Type::VectorTyID: {
 263       const VectorType *VT = cast<VectorType>(T);
 264       // VECTOR [numelts, eltty]
 265       Code = bitc::TYPE_CODE_VECTOR;
 266       TypeVals.push_back(VT->getNumElements());
 267       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 268       break;
 269     }
 270     }
 271
 272     // Emit the finished record.
 273     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 274     TypeVals.clear();
 275   }
 276
 277   Stream.ExitBlock();
 278 }
 279
 280 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 281   switch (GV->getLinkage()) {
 282   default: llvm_unreachable("Invalid linkage!");
 283   case GlobalValue::ExternalLinkage:            return 0;
 284   case GlobalValue::WeakAnyLinkage:             return 1;
 285   case GlobalValue::AppendingLinkage:           return 2;
 286   case GlobalValue::InternalLinkage:            return 3;
 287   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 288   case GlobalValue::DLLImportLinkage:           return 5;
 289   case GlobalValue::DLLExportLinkage:           return 6;
 290   case GlobalValue::ExternalWeakLinkage:        return 7;
 291   case GlobalValue::CommonLinkage:              return 8;
 292   case GlobalValue::PrivateLinkage:             return 9;
 293   case GlobalValue::WeakODRLinkage:             return 10;
 294   case GlobalValue::LinkOnceODRLinkage:         return 11;
 295   case GlobalValue::AvailableExternallyLinkage: return 12;
 296   case GlobalValue::LinkerPrivateLinkage:       return 13;
 297   }
 298 }
 299
 300 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 301   switch (GV->getVisibility()) {
 302   default: llvm_unreachable("Invalid visibility!");
 303   case GlobalValue::DefaultVisibility:   return 0;
 304   case GlobalValue::HiddenVisibility:    return 1;
 305   case GlobalValue::ProtectedVisibility: return 2;
 306   }
 307 }
 308
 309 // Emit top-level description of module, including target triple, inline asm,
 310 // descriptors for global variables, and function prototype info.
 311 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 312                             BitstreamWriter &Stream) {
 313   // Emit the list of dependent libraries for the Module.
 314   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 315     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 316
 317   // Emit various pieces of data attached to a module.
 318   if (!M->getTargetTriple().empty())
 319     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 320                       0/*TODO*/, Stream);
 321   if (!M->getDataLayout().empty())
 322     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 323                       0/*TODO*/, Stream);
 324   if (!M->getModuleInlineAsm().empty())
 325     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 326                       0/*TODO*/, Stream);
 327
 328   // Emit information about sections and GC, computing how many there are. Also
 329   // compute the maximum alignment value.
 330   std::map<std::string, unsigned> SectionMap;
 331   std::map<std::string, unsigned> GCMap;
 332   unsigned MaxAlignment = 0;
 333   unsigned MaxGlobalType = 0;
 334   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 335        GV != E; ++GV) {
 336     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 337     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 338
 339     if (!GV->hasSection()) continue;
 340     // Give section names unique ID's.
 341     unsigned &Entry = SectionMap[GV->getSection()];
 342     if (Entry != 0) continue;
 343     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 344                       0/*TODO*/, Stream);
 345     Entry = SectionMap.size();
 346   }
 347   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 348     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 349     if (F->hasSection()) {
 350       // Give section names unique ID's.
 351       unsigned &Entry = SectionMap[F->getSection()];
 352       if (!Entry) {
 353         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 354                           0/*TODO*/, Stream);
 355         Entry = SectionMap.size();
 356       }
 357     }
 358     if (F->hasGC()) {
 359       // Same for GC names.
 360       unsigned &Entry = GCMap[F->getGC()];
 361       if (!Entry) {
 362         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 363                           0/*TODO*/, Stream);
 364         Entry = GCMap.size();
 365       }
 366     }
 367   }
 368
 369   // Emit abbrev for globals, now that we know # sections and max alignment.
 370   unsigned SimpleGVarAbbrev = 0;
 371   if (!M->global_empty()) {
 372     // Add an abbrev for common globals with no visibility or thread localness.
 373     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 374     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 376                               Log2_32_Ceil(MaxGlobalType+1)));
 377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 380     if (MaxAlignment == 0)                                      // Alignment.
 381       Abbv->Add(BitCodeAbbrevOp(0));
 382     else {
 383       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 384       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 385                                Log2_32_Ceil(MaxEncAlignment+1)));
 386     }
 387     if (SectionMap.empty())                                    // Section.
 388       Abbv->Add(BitCodeAbbrevOp(0));
 389     else
 390       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 391                                Log2_32_Ceil(SectionMap.size()+1)));
 392     // Don't bother emitting vis + thread local.
 393     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 394   }
 395
 396   // Emit the global variable information.
 397   SmallVector<unsigned, 64> Vals;
 398   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 399        GV != E; ++GV) {
 400     unsigned AbbrevToUse = 0;
 401
 402     // GLOBALVAR: [type, isconst, initid,
 403     //             linkage, alignment, section, visibility, threadlocal]
 404     Vals.push_back(VE.getTypeID(GV->getType()));
 405     Vals.push_back(GV->isConstant());
 406     Vals.push_back(GV->isDeclaration() ? 0 :
 407                    (VE.getValueID(GV->getInitializer()) + 1));
 408     Vals.push_back(getEncodedLinkage(GV));
 409     Vals.push_back(Log2_32(GV->getAlignment())+1);
 410     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 411     if (GV->isThreadLocal() ||
 412         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 413       Vals.push_back(getEncodedVisibility(GV));
 414       Vals.push_back(GV->isThreadLocal());
 415     } else {
 416       AbbrevToUse = SimpleGVarAbbrev;
 417     }
 418
 419     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 420     Vals.clear();
 421   }
 422
 423   // Emit the function proto information.
 424   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 425     // FUNCTION:  [type, callingconv, isproto, paramattr,
 426     //             linkage, alignment, section, visibility, gc]
 427     Vals.push_back(VE.getTypeID(F->getType()));
 428     Vals.push_back(F->getCallingConv());
 429     Vals.push_back(F->isDeclaration());
 430     Vals.push_back(getEncodedLinkage(F));
 431     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 432     Vals.push_back(Log2_32(F->getAlignment())+1);
 433     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 434     Vals.push_back(getEncodedVisibility(F));
 435     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 436
 437     unsigned AbbrevToUse = 0;
 438     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 439     Vals.clear();
 440   }
 441
 442
 443   // Emit the alias information.
 444   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 445        AI != E; ++AI) {
 446     Vals.push_back(VE.getTypeID(AI->getType()));
 447     Vals.push_back(VE.getValueID(AI->getAliasee()));
 448     Vals.push_back(getEncodedLinkage(AI));
 449     Vals.push_back(getEncodedVisibility(AI));
 450     unsigned AbbrevToUse = 0;
 451     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 452     Vals.clear();
 453   }
 454 }
 455
 456 static uint64_t GetOptimizationFlags(const Value *V) {
 457   uint64_t Flags = 0;
 458
 459   if (const OverflowingBinaryOperator *OBO =
 460         dyn_cast<OverflowingBinaryOperator>(V)) {
 461     if (OBO->hasNoSignedWrap())
 462       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 463     if (OBO->hasNoUnsignedWrap())
 464       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 465   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 466     if (Div->isExact())
 467       Flags |= 1 << bitc::SDIV_EXACT;
 468   }
 469
 470   return Flags;
 471 }
 472
 473 static void WriteMDNode(const MDNode *N,
 474                         const ValueEnumerator &VE,
 475                         BitstreamWriter &Stream,
 476                         SmallVector<uint64_t, 64> &Record) {
 477   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 478     if (N->getOperand(i)) {
 479       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 480       Record.push_back(VE.getValueID(N->getOperand(i)));
 481     } else {
 482       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 483       Record.push_back(0);
 484     }
 485   }
 486   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 487                                            bitc::METADATA_NODE;
 488   Stream.EmitRecord(MDCode, Record, 0);
 489   Record.clear();
 490 }
 491
 492 static void WriteModuleMetadata(const ValueEnumerator &VE,
 493                                 BitstreamWriter &Stream) {
 494   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 495   bool StartedMetadataBlock = false;
 496   unsigned MDSAbbrev = 0;
 497   SmallVector<uint64_t, 64> Record;
 498   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 499
 500     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 501       if (!N->isFunctionLocal() || !N->getFunction()) {
 502         if (!StartedMetadataBlock) {
 503           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 504           StartedMetadataBlock = true;
 505         }
 506         WriteMDNode(N, VE, Stream, Record);
 507       }
 508     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 509       if (!StartedMetadataBlock)  {
 510         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 511
 512         // Abbrev for METADATA_STRING.
 513         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 514         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 515         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 516         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 517         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 518         StartedMetadataBlock = true;
 519       }
 520
 521       // Code: [strchar x N]
 522       Record.append(MDS->begin(), MDS->end());
 523
 524       // Emit the finished record.
 525       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 526       Record.clear();
 527     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 528       if (!StartedMetadataBlock)  {
 529         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 530         StartedMetadataBlock = true;
 531       }
 532
 533       // Write name.
 534       StringRef Str = NMD->getName();
 535       for (unsigned i = 0, e = Str.size(); i != e; ++i)
 536         Record.push_back(Str[i]);
 537       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 538       Record.clear();
 539
 540       // Write named metadata operands.
 541       for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
 542         if (NMD->getOperand(i))
 543           Record.push_back(VE.getValueID(NMD->getOperand(i)));
 544         else
 545           Record.push_back(~0U);
 546       }
 547       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 548       Record.clear();
 549     }
 550   }
 551
 552   if (StartedMetadataBlock)
 553     Stream.ExitBlock();
 554 }
 555
 556 static void WriteFunctionLocalMetadata(const Function &F,
 557                                        const ValueEnumerator &VE,
 558                                        BitstreamWriter &Stream) {
 559   bool StartedMetadataBlock = false;
 560   SmallVector<uint64_t, 64> Record;
 561   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 562
 563   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 564     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first))
 565       if (N->isFunctionLocal() && N->getFunction() == &F) {
 566         if (!StartedMetadataBlock) {
 567           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 568           StartedMetadataBlock = true;
 569         }
 570         WriteMDNode(N, VE, Stream, Record);
 571       }
 572
 573   if (StartedMetadataBlock)
 574     Stream.ExitBlock();
 575 }
 576
 577 static void WriteMetadataAttachment(const Function &F,
 578                                     const ValueEnumerator &VE,
 579                                     BitstreamWriter &Stream) {
 580   bool StartedMetadataBlock = false;
 581   SmallVector<uint64_t, 64> Record;
 582
 583   // Write metadata attachments
 584   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 585   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 586
 587   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 588     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 589          I != E; ++I) {
 590       MDs.clear();
 591       I->getAllMetadata(MDs);
 592
 593       // If no metadata, ignore instruction.
 594       if (MDs.empty()) continue;
 595
 596       Record.push_back(VE.getInstructionID(I));
 597
 598       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 599         Record.push_back(MDs[i].first);
 600         Record.push_back(VE.getValueID(MDs[i].second));
 601       }
 602       if (!StartedMetadataBlock)  {
 603         Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 604         StartedMetadataBlock = true;
 605       }
 606       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 607       Record.clear();
 608     }
 609
 610   if (StartedMetadataBlock)
 611     Stream.ExitBlock();
 612 }
 613
 614 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 615   SmallVector<uint64_t, 64> Record;
 616
 617   // Write metadata kinds
 618   // METADATA_KIND - [n x [id, name]]
 619   SmallVector<StringRef, 4> Names;
 620   M->getMDKindNames(Names);
 621
 622   assert(Names[0] == "" && "MDKind #0 is invalid");
 623   if (Names.size() == 1) return;
 624
 625   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 626
 627   for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
 628     Record.push_back(MDKindID);
 629     StringRef KName = Names[MDKindID];
 630     Record.append(KName.begin(), KName.end());
 631
 632     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 633     Record.clear();
 634   }
 635
 636   Stream.ExitBlock();
 637 }
 638
 639 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 640                            const ValueEnumerator &VE,
 641                            BitstreamWriter &Stream, bool isGlobal) {
 642   if (FirstVal == LastVal) return;
 643
 644   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 645
 646   unsigned AggregateAbbrev = 0;
 647   unsigned String8Abbrev = 0;
 648   unsigned CString7Abbrev = 0;
 649   unsigned CString6Abbrev = 0;
 650   // If this is a constant pool for the module, emit module-specific abbrevs.
 651   if (isGlobal) {
 652     // Abbrev for CST_CODE_AGGREGATE.
 653     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 654     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 655     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 657     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 658
 659     // Abbrev for CST_CODE_STRING.
 660     Abbv = new BitCodeAbbrev();
 661     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 664     String8Abbrev = Stream.EmitAbbrev(Abbv);
 665     // Abbrev for CST_CODE_CSTRING.
 666     Abbv = new BitCodeAbbrev();
 667     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 670     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 671     // Abbrev for CST_CODE_CSTRING.
 672     Abbv = new BitCodeAbbrev();
 673     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 674     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 676     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 677   }
 678
 679   SmallVector<uint64_t, 64> Record;
 680
 681   const ValueEnumerator::ValueList &Vals = VE.getValues();
 682   const Type *LastTy = 0;
 683   for (unsigned i = FirstVal; i != LastVal; ++i) {
 684     const Value *V = Vals[i].first;
 685     // If we need to switch types, do so now.
 686     if (V->getType() != LastTy) {
 687       LastTy = V->getType();
 688       Record.push_back(VE.getTypeID(LastTy));
 689       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 690                         CONSTANTS_SETTYPE_ABBREV);
 691       Record.clear();
 692     }
 693
 694     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 695       Record.push_back(unsigned(IA->hasSideEffects()) |
 696                        unsigned(IA->isAlignStack()) << 1);
 697
 698       // Add the asm string.
 699       const std::string &AsmStr = IA->getAsmString();
 700       Record.push_back(AsmStr.size());
 701       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 702         Record.push_back(AsmStr[i]);
 703
 704       // Add the constraint string.
 705       const std::string &ConstraintStr = IA->getConstraintString();
 706       Record.push_back(ConstraintStr.size());
 707       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 708         Record.push_back(ConstraintStr[i]);
 709       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 710       Record.clear();
 711       continue;
 712     }
 713     const Constant *C = cast<Constant>(V);
 714     unsigned Code = -1U;
 715     unsigned AbbrevToUse = 0;
 716     if (C->isNullValue()) {
 717       Code = bitc::CST_CODE_NULL;
 718     } else if (isa<UndefValue>(C)) {
 719       Code = bitc::CST_CODE_UNDEF;
 720     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 721       if (IV->getBitWidth() <= 64) {
 722         int64_t V = IV->getSExtValue();
 723         if (V >= 0)
 724           Record.push_back(V << 1);
 725         else
 726           Record.push_back((-V << 1) | 1);
 727         Code = bitc::CST_CODE_INTEGER;
 728         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 729       } else {                             // Wide integers, > 64 bits in size.
 730         // We have an arbitrary precision integer value to write whose
 731         // bit width is > 64. However, in canonical unsigned integer
 732         // format it is likely that the high bits are going to be zero.
 733         // So, we only write the number of active words.
 734         unsigned NWords = IV->getValue().getActiveWords();
 735         const uint64_t *RawWords = IV->getValue().getRawData();
 736         for (unsigned i = 0; i != NWords; ++i) {
 737           int64_t V = RawWords[i];
 738           if (V >= 0)
 739             Record.push_back(V << 1);
 740           else
 741             Record.push_back((-V << 1) | 1);
 742         }
 743         Code = bitc::CST_CODE_WIDE_INTEGER;
 744       }
 745     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 746       Code = bitc::CST_CODE_FLOAT;
 747       const Type *Ty = CFP->getType();
 748       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 749         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 750       } else if (Ty->isX86_FP80Ty()) {
 751         // api needed to prevent premature destruction
 752         // bits are not in the same order as a normal i80 APInt, compensate.
 753         APInt api = CFP->getValueAPF().bitcastToAPInt();
 754         const uint64_t *p = api.getRawData();
 755         Record.push_back((p[1] << 48) | (p[0] >> 16));
 756         Record.push_back(p[0] & 0xffffLL);
 757       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 758         APInt api = CFP->getValueAPF().bitcastToAPInt();
 759         const uint64_t *p = api.getRawData();
 760         Record.push_back(p[0]);
 761         Record.push_back(p[1]);
 762       } else {
 763         assert (0 && "Unknown FP type!");
 764       }
 765     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 766       const ConstantArray *CA = cast<ConstantArray>(C);
 767       // Emit constant strings specially.
 768       unsigned NumOps = CA->getNumOperands();
 769       // If this is a null-terminated string, use the denser CSTRING encoding.
 770       if (CA->getOperand(NumOps-1)->isNullValue()) {
 771         Code = bitc::CST_CODE_CSTRING;
 772         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 773       } else {
 774         Code = bitc::CST_CODE_STRING;
 775         AbbrevToUse = String8Abbrev;
 776       }
 777       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 778       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 779       for (unsigned i = 0; i != NumOps; ++i) {
 780         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 781         Record.push_back(V);
 782         isCStr7 &= (V & 128) == 0;
 783         if (isCStrChar6)
 784           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 785       }
 786
 787       if (isCStrChar6)
 788         AbbrevToUse = CString6Abbrev;
 789       else if (isCStr7)
 790         AbbrevToUse = CString7Abbrev;
 791     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 792                isa<ConstantVector>(V)) {
 793       Code = bitc::CST_CODE_AGGREGATE;
 794       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 795         Record.push_back(VE.getValueID(C->getOperand(i)));
 796       AbbrevToUse = AggregateAbbrev;
 797     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 798       switch (CE->getOpcode()) {
 799       default:
 800         if (Instruction::isCast(CE->getOpcode())) {
 801           Code = bitc::CST_CODE_CE_CAST;
 802           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 803           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 804           Record.push_back(VE.getValueID(C->getOperand(0)));
 805           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 806         } else {
 807           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 808           Code = bitc::CST_CODE_CE_BINOP;
 809           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 810           Record.push_back(VE.getValueID(C->getOperand(0)));
 811           Record.push_back(VE.getValueID(C->getOperand(1)));
 812           uint64_t Flags = GetOptimizationFlags(CE);
 813           if (Flags != 0)
 814             Record.push_back(Flags);
 815         }
 816         break;
 817       case Instruction::GetElementPtr:
 818         Code = bitc::CST_CODE_CE_GEP;
 819         if (cast<GEPOperator>(C)->isInBounds())
 820           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 821         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 822           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 823           Record.push_back(VE.getValueID(C->getOperand(i)));
 824         }
 825         break;
 826       case Instruction::Select:
 827         Code = bitc::CST_CODE_CE_SELECT;
 828         Record.push_back(VE.getValueID(C->getOperand(0)));
 829         Record.push_back(VE.getValueID(C->getOperand(1)));
 830         Record.push_back(VE.getValueID(C->getOperand(2)));
 831         break;
 832       case Instruction::ExtractElement:
 833         Code = bitc::CST_CODE_CE_EXTRACTELT;
 834         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 835         Record.push_back(VE.getValueID(C->getOperand(0)));
 836         Record.push_back(VE.getValueID(C->getOperand(1)));
 837         break;
 838       case Instruction::InsertElement:
 839         Code = bitc::CST_CODE_CE_INSERTELT;
 840         Record.push_back(VE.getValueID(C->getOperand(0)));
 841         Record.push_back(VE.getValueID(C->getOperand(1)));
 842         Record.push_back(VE.getValueID(C->getOperand(2)));
 843         break;
 844       case Instruction::ShuffleVector:
 845         // If the return type and argument types are the same, this is a
 846         // standard shufflevector instruction.  If the types are different,
 847         // then the shuffle is widening or truncating the input vectors, and
 848         // the argument type must also be encoded.
 849         if (C->getType() == C->getOperand(0)->getType()) {
 850           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 851         } else {
 852           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 853           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 854         }
 855         Record.push_back(VE.getValueID(C->getOperand(0)));
 856         Record.push_back(VE.getValueID(C->getOperand(1)));
 857         Record.push_back(VE.getValueID(C->getOperand(2)));
 858         break;
 859       case Instruction::ICmp:
 860       case Instruction::FCmp:
 861         Code = bitc::CST_CODE_CE_CMP;
 862         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 863         Record.push_back(VE.getValueID(C->getOperand(0)));
 864         Record.push_back(VE.getValueID(C->getOperand(1)));
 865         Record.push_back(CE->getPredicate());
 866         break;
 867       }
 868     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 869       assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
 870              "Malformed blockaddress");
 871       Code = bitc::CST_CODE_BLOCKADDRESS;
 872       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 873       Record.push_back(VE.getValueID(BA->getFunction()));
 874       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 875     } else {
 876       llvm_unreachable("Unknown constant!");
 877     }
 878     Stream.EmitRecord(Code, Record, AbbrevToUse);
 879     Record.clear();
 880   }
 881
 882   Stream.ExitBlock();
 883 }
 884
 885 static void WriteModuleConstants(const ValueEnumerator &VE,
 886                                  BitstreamWriter &Stream) {
 887   const ValueEnumerator::ValueList &Vals = VE.getValues();
 888
 889   // Find the first constant to emit, which is the first non-globalvalue value.
 890   // We know globalvalues have been emitted by WriteModuleInfo.
 891   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 892     if (!isa<GlobalValue>(Vals[i].first)) {
 893       WriteConstants(i, Vals.size(), VE, Stream, true);
 894       return;
 895     }
 896   }
 897 }
 898
 899 /// PushValueAndType - The file has to encode both the value and type id for
 900 /// many values, because we need to know what type to create for forward
 901 /// references.  However, most operands are not forward references, so this type
 902 /// field is not needed.
 903 ///
 904 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 905 /// instruction ID, then it is a forward reference, and it also includes the
 906 /// type ID.
 907 static bool PushValueAndType(const Value *V, unsigned InstID,
 908                              SmallVector<unsigned, 64> &Vals,
 909                              ValueEnumerator &VE) {
 910   unsigned ValID = VE.getValueID(V);
 911   Vals.push_back(ValID);
 912   if (ValID >= InstID) {
 913     Vals.push_back(VE.getTypeID(V->getType()));
 914     return true;
 915   }
 916   return false;
 917 }
 918
 919 /// WriteInstruction - Emit an instruction to the specified stream.
 920 static void WriteInstruction(const Instruction &I, unsigned InstID,
 921                              ValueEnumerator &VE, BitstreamWriter &Stream,
 922                              SmallVector<unsigned, 64> &Vals) {
 923   unsigned Code = 0;
 924   unsigned AbbrevToUse = 0;
 925   VE.setInstructionID(&I);
 926   switch (I.getOpcode()) {
 927   default:
 928     if (Instruction::isCast(I.getOpcode())) {
 929       Code = bitc::FUNC_CODE_INST_CAST;
 930       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 931         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 932       Vals.push_back(VE.getTypeID(I.getType()));
 933       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 934     } else {
 935       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 936       Code = bitc::FUNC_CODE_INST_BINOP;
 937       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 938         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 939       Vals.push_back(VE.getValueID(I.getOperand(1)));
 940       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 941       uint64_t Flags = GetOptimizationFlags(&I);
 942       if (Flags != 0) {
 943         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 944           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 945         Vals.push_back(Flags);
 946       }
 947     }
 948     break;
 949
 950   case Instruction::GetElementPtr:
 951     Code = bitc::FUNC_CODE_INST_GEP;
 952     if (cast<GEPOperator>(&I)->isInBounds())
 953       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 954     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 955       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 956     break;
 957   case Instruction::ExtractValue: {
 958     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 959     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 960     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 961     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 962       Vals.push_back(*i);
 963     break;
 964   }
 965   case Instruction::InsertValue: {
 966     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 967     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 968     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 969     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 970     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 971       Vals.push_back(*i);
 972     break;
 973   }
 974   case Instruction::Select:
 975     Code = bitc::FUNC_CODE_INST_VSELECT;
 976     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 977     Vals.push_back(VE.getValueID(I.getOperand(2)));
 978     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 979     break;
 980   case Instruction::ExtractElement:
 981     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 982     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 983     Vals.push_back(VE.getValueID(I.getOperand(1)));
 984     break;
 985   case Instruction::InsertElement:
 986     Code = bitc::FUNC_CODE_INST_INSERTELT;
 987     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 988     Vals.push_back(VE.getValueID(I.getOperand(1)));
 989     Vals.push_back(VE.getValueID(I.getOperand(2)));
 990     break;
 991   case Instruction::ShuffleVector:
 992     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 993     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 994     Vals.push_back(VE.getValueID(I.getOperand(1)));
 995     Vals.push_back(VE.getValueID(I.getOperand(2)));
 996     break;
 997   case Instruction::ICmp:
 998   case Instruction::FCmp:
 999     // compare returning Int1Ty or vector of Int1Ty
1000     Code = bitc::FUNC_CODE_INST_CMP2;
1001     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1002     Vals.push_back(VE.getValueID(I.getOperand(1)));
1003     Vals.push_back(cast<CmpInst>(I).getPredicate());
1004     break;
1005
1006   case Instruction::Ret:
1007     {
1008       Code = bitc::FUNC_CODE_INST_RET;
1009       unsigned NumOperands = I.getNumOperands();
1010       if (NumOperands == 0)
1011         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1012       else if (NumOperands == 1) {
1013         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1014           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1015       } else {
1016         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1017           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1018       }
1019     }
1020     break;
1021   case Instruction::Br:
1022     {
1023       Code = bitc::FUNC_CODE_INST_BR;
1024       BranchInst &II = cast<BranchInst>(I);
1025       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1026       if (II.isConditional()) {
1027         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1028         Vals.push_back(VE.getValueID(II.getCondition()));
1029       }
1030     }
1031     break;
1032   case Instruction::Switch:
1033     Code = bitc::FUNC_CODE_INST_SWITCH;
1034     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1035     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1036       Vals.push_back(VE.getValueID(I.getOperand(i)));
1037     break;
1038   case Instruction::IndirectBr:
1039     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1040     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1041     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1042       Vals.push_back(VE.getValueID(I.getOperand(i)));
1043     break;
1044
1045   case Instruction::Invoke: {
1046     const InvokeInst *II = cast<InvokeInst>(&I);
1047     const Value *Callee(II->getCalledValue());
1048     const PointerType *PTy = cast<PointerType>(Callee->getType());
1049     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1050     Code = bitc::FUNC_CODE_INST_INVOKE;
1051
1052     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1053     Vals.push_back(II->getCallingConv());
1054     Vals.push_back(VE.getValueID(II->getNormalDest()));
1055     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1056     PushValueAndType(Callee, InstID, Vals, VE);
1057
1058     // Emit value #'s for the fixed parameters.
1059     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1060       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1061
1062     // Emit type/value pairs for varargs params.
1063     if (FTy->isVarArg()) {
1064       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1065            i != e; ++i)
1066         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1067     }
1068     break;
1069   }
1070   case Instruction::Unwind:
1071     Code = bitc::FUNC_CODE_INST_UNWIND;
1072     break;
1073   case Instruction::Unreachable:
1074     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1075     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1076     break;
1077
1078   case Instruction::PHI:
1079     Code = bitc::FUNC_CODE_INST_PHI;
1080     Vals.push_back(VE.getTypeID(I.getType()));
1081     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1082       Vals.push_back(VE.getValueID(I.getOperand(i)));
1083     break;
1084
1085   case Instruction::Alloca:
1086     Code = bitc::FUNC_CODE_INST_ALLOCA;
1087     Vals.push_back(VE.getTypeID(I.getType()));
1088     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1089     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1090     break;
1091
1092   case Instruction::Load:
1093     Code = bitc::FUNC_CODE_INST_LOAD;
1094     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1095       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1096
1097     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1098     Vals.push_back(cast<LoadInst>(I).isVolatile());
1099     break;
1100   case Instruction::Store:
1101     Code = bitc::FUNC_CODE_INST_STORE2;
1102     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1103     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1104     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1105     Vals.push_back(cast<StoreInst>(I).isVolatile());
1106     break;
1107   case Instruction::Call: {
1108     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1109     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1110
1111     Code = bitc::FUNC_CODE_INST_CALL;
1112
1113     const CallInst *CI = cast<CallInst>(&I);
1114     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1115     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1116     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1117
1118     // Emit value #'s for the fixed parameters.
1119     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1120       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1121
1122     // Emit type/value pairs for varargs params.
1123     if (FTy->isVarArg()) {
1124       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1125       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1126            i != e; ++i)
1127         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1128     }
1129     break;
1130   }
1131   case Instruction::VAArg:
1132     Code = bitc::FUNC_CODE_INST_VAARG;
1133     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1134     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1135     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1136     break;
1137   }
1138
1139   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1140   Vals.clear();
1141 }
1142
1143 // Emit names for globals/functions etc.
1144 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1145                                   const ValueEnumerator &VE,
1146                                   BitstreamWriter &Stream) {
1147   if (VST.empty()) return;
1148   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1149
1150   // FIXME: Set up the abbrev, we know how many values there are!
1151   // FIXME: We know if the type names can use 7-bit ascii.
1152   SmallVector<unsigned, 64> NameVals;
1153
1154   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1155        SI != SE; ++SI) {
1156
1157     const ValueName &Name = *SI;
1158
1159     // Figure out the encoding to use for the name.
1160     bool is7Bit = true;
1161     bool isChar6 = true;
1162     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1163          C != E; ++C) {
1164       if (isChar6)
1165         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1166       if ((unsigned char)*C & 128) {
1167         is7Bit = false;
1168         break;  // don't bother scanning the rest.
1169       }
1170     }
1171
1172     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1173
1174     // VST_ENTRY:   [valueid, namechar x N]
1175     // VST_BBENTRY: [bbid, namechar x N]
1176     unsigned Code;
1177     if (isa<BasicBlock>(SI->getValue())) {
1178       Code = bitc::VST_CODE_BBENTRY;
1179       if (isChar6)
1180         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1181     } else {
1182       Code = bitc::VST_CODE_ENTRY;
1183       if (isChar6)
1184         AbbrevToUse = VST_ENTRY_6_ABBREV;
1185       else if (is7Bit)
1186         AbbrevToUse = VST_ENTRY_7_ABBREV;
1187     }
1188
1189     NameVals.push_back(VE.getValueID(SI->getValue()));
1190     for (const char *P = Name.getKeyData(),
1191          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1192       NameVals.push_back((unsigned char)*P);
1193
1194     // Emit the finished record.
1195     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1196     NameVals.clear();
1197   }
1198   Stream.ExitBlock();
1199 }
1200
1201 /// WriteFunction - Emit a function body to the module stream.
1202 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1203                           BitstreamWriter &Stream) {
1204   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1205   VE.incorporateFunction(F);
1206
1207   SmallVector<unsigned, 64> Vals;
1208
1209   // Emit the number of basic blocks, so the reader can create them ahead of
1210   // time.
1211   Vals.push_back(VE.getBasicBlocks().size());
1212   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1213   Vals.clear();
1214
1215   // If there are function-local constants, emit them now.
1216   unsigned CstStart, CstEnd;
1217   VE.getFunctionConstantRange(CstStart, CstEnd);
1218   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1219
1220   // If there is function-local metadata, emit it now.
1221   WriteFunctionLocalMetadata(F, VE, Stream);
1222
1223   // Keep a running idea of what the instruction ID is.
1224   unsigned InstID = CstEnd;
1225
1226   // Finally, emit all the instructions, in order.
1227   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1228     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1229          I != E; ++I) {
1230       WriteInstruction(*I, InstID, VE, Stream, Vals);
1231       if (!I->getType()->isVoidTy())
1232         ++InstID;
1233     }
1234
1235   // Emit names for all the instructions etc.
1236   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1237
1238   WriteMetadataAttachment(F, VE, Stream);
1239   VE.purgeFunction();
1240   Stream.ExitBlock();
1241 }
1242
1243 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1244 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1245                                  const ValueEnumerator &VE,
1246                                  BitstreamWriter &Stream) {
1247   if (TST.empty()) return;
1248
1249   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1250
1251   // 7-bit fixed width VST_CODE_ENTRY strings.
1252   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1253   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1254   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1255                             Log2_32_Ceil(VE.getTypes().size()+1)));
1256   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1257   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1258   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1259
1260   SmallVector<unsigned, 64> NameVals;
1261
1262   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1263        TI != TE; ++TI) {
1264     // TST_ENTRY: [typeid, namechar x N]
1265     NameVals.push_back(VE.getTypeID(TI->second));
1266
1267     const std::string &Str = TI->first;
1268     bool is7Bit = true;
1269     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1270       NameVals.push_back((unsigned char)Str[i]);
1271       if (Str[i] & 128)
1272         is7Bit = false;
1273     }
1274
1275     // Emit the finished record.
1276     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1277     NameVals.clear();
1278   }
1279
1280   Stream.ExitBlock();
1281 }
1282
1283 // Emit blockinfo, which defines the standard abbreviations etc.
1284 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1285   // We only want to emit block info records for blocks that have multiple
1286   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1287   // blocks can defined their abbrevs inline.
1288   Stream.EnterBlockInfoBlock(2);
1289
1290   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1291     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1296     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1297                                    Abbv) != VST_ENTRY_8_ABBREV)
1298       llvm_unreachable("Unexpected abbrev ordering!");
1299   }
1300
1301   { // 7-bit fixed width VST_ENTRY strings.
1302     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1303     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1307     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1308                                    Abbv) != VST_ENTRY_7_ABBREV)
1309       llvm_unreachable("Unexpected abbrev ordering!");
1310   }
1311   { // 6-bit char6 VST_ENTRY strings.
1312     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1313     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1314     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1317     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1318                                    Abbv) != VST_ENTRY_6_ABBREV)
1319       llvm_unreachable("Unexpected abbrev ordering!");
1320   }
1321   { // 6-bit char6 VST_BBENTRY strings.
1322     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1323     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1324     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1325     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1327     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1328                                    Abbv) != VST_BBENTRY_6_ABBREV)
1329       llvm_unreachable("Unexpected abbrev ordering!");
1330   }
1331
1332
1333
1334   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1335     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1336     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1337     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1338                               Log2_32_Ceil(VE.getTypes().size()+1)));
1339     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1340                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1341       llvm_unreachable("Unexpected abbrev ordering!");
1342   }
1343
1344   { // INTEGER abbrev for CONSTANTS_BLOCK.
1345     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1346     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1348     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1349                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1350       llvm_unreachable("Unexpected abbrev ordering!");
1351   }
1352
1353   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1354     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1355     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1356     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1358                               Log2_32_Ceil(VE.getTypes().size()+1)));
1359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1360
1361     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1362                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1363       llvm_unreachable("Unexpected abbrev ordering!");
1364   }
1365   { // NULL abbrev for CONSTANTS_BLOCK.
1366     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1367     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1368     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1369                                    Abbv) != CONSTANTS_NULL_Abbrev)
1370       llvm_unreachable("Unexpected abbrev ordering!");
1371   }
1372
1373   // FIXME: This should only use space for first class types!
1374
1375   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1376     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1377     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1381     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1382                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1383       llvm_unreachable("Unexpected abbrev ordering!");
1384   }
1385   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1386     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1387     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1390     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1391     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1392                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1393       llvm_unreachable("Unexpected abbrev ordering!");
1394   }
1395   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1396     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1397     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1399     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1400     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1402     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1403                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1404       llvm_unreachable("Unexpected abbrev ordering!");
1405   }
1406   { // INST_CAST abbrev for FUNCTION_BLOCK.
1407     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1408     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1409     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1411                               Log2_32_Ceil(VE.getTypes().size()+1)));
1412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1413     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1414                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1415       llvm_unreachable("Unexpected abbrev ordering!");
1416   }
1417
1418   { // INST_RET abbrev for FUNCTION_BLOCK.
1419     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1420     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1421     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1422                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1423       llvm_unreachable("Unexpected abbrev ordering!");
1424   }
1425   { // INST_RET abbrev for FUNCTION_BLOCK.
1426     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1427     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1429     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1430                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1431       llvm_unreachable("Unexpected abbrev ordering!");
1432   }
1433   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1434     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1435     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1436     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1437                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1438       llvm_unreachable("Unexpected abbrev ordering!");
1439   }
1440
1441   Stream.ExitBlock();
1442 }
1443
1444
1445 /// WriteModule - Emit the specified module to the bitstream.
1446 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1447   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1448
1449   // Emit the version number if it is non-zero.
1450   if (CurVersion) {
1451     SmallVector<unsigned, 1> Vals;
1452     Vals.push_back(CurVersion);
1453     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1454   }
1455
1456   // Analyze the module, enumerating globals, functions, etc.
1457   ValueEnumerator VE(M);
1458
1459   // Emit blockinfo, which defines the standard abbreviations etc.
1460   WriteBlockInfo(VE, Stream);
1461
1462   // Emit information about parameter attributes.
1463   WriteAttributeTable(VE, Stream);
1464
1465   // Emit information describing all of the types in the module.
1466   WriteTypeTable(VE, Stream);
1467
1468   // Emit top-level description of module, including target triple, inline asm,
1469   // descriptors for global variables, and function prototype info.
1470   WriteModuleInfo(M, VE, Stream);
1471
1472   // Emit constants.
1473   WriteModuleConstants(VE, Stream);
1474
1475   // Emit metadata.
1476   WriteModuleMetadata(VE, Stream);
1477
1478   // Emit function bodies.
1479   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1480     if (!I->isDeclaration())
1481       WriteFunction(*I, VE, Stream);
1482
1483   // Emit metadata.
1484   WriteModuleMetadataStore(M, Stream);
1485
1486   // Emit the type symbol table information.
1487   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1488
1489   // Emit names for globals/functions etc.
1490   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1491
1492   Stream.ExitBlock();
1493 }
1494
1495 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1496 /// header and trailer to make it compatible with the system archiver.  To do
1497 /// this we emit the following header, and then emit a trailer that pads the
1498 /// file out to be a multiple of 16 bytes.
1499 ///
1500 /// struct bc_header {
1501 ///   uint32_t Magic;         // 0x0B17C0DE
1502 ///   uint32_t Version;       // Version, currently always 0.
1503 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1504 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1505 ///   uint32_t CPUType;       // CPU specifier.
1506 ///   ... potentially more later ...
1507 /// };
1508 enum {
1509   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1510   DarwinBCHeaderSize = 5*4
1511 };
1512
1513 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1514                                const std::string &TT) {
1515   unsigned CPUType = ~0U;
1516
1517   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1518   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1519   // specific constants here because they are implicitly part of the Darwin ABI.
1520   enum {
1521     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1522     DARWIN_CPU_TYPE_X86        = 7,
1523     DARWIN_CPU_TYPE_POWERPC    = 18
1524   };
1525
1526   if (TT.find("x86_64-") == 0)
1527     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1528   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1529            TT[4] == '-' && TT[1] - '3' < 6)
1530     CPUType = DARWIN_CPU_TYPE_X86;
1531   else if (TT.find("powerpc-") == 0)
1532     CPUType = DARWIN_CPU_TYPE_POWERPC;
1533   else if (TT.find("powerpc64-") == 0)
1534     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1535
1536   // Traditional Bitcode starts after header.
1537   unsigned BCOffset = DarwinBCHeaderSize;
1538
1539   Stream.Emit(0x0B17C0DE, 32);
1540   Stream.Emit(0         , 32);  // Version.
1541   Stream.Emit(BCOffset  , 32);
1542   Stream.Emit(0         , 32);  // Filled in later.
1543   Stream.Emit(CPUType   , 32);
1544 }
1545
1546 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1547 /// finalize the header.
1548 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1549   // Update the size field in the header.
1550   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1551
1552   // If the file is not a multiple of 16 bytes, insert dummy padding.
1553   while (BufferSize & 15) {
1554     Stream.Emit(0, 8);
1555     ++BufferSize;
1556   }
1557 }
1558
1559
1560 /// WriteBitcodeToFile - Write the specified module to the specified output
1561 /// stream.
1562 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1563   std::vector<unsigned char> Buffer;
1564   BitstreamWriter Stream(Buffer);
1565
1566   Buffer.reserve(256*1024);
1567
1568   WriteBitcodeToStream( M, Stream );
1569
1570   // If writing to stdout, set binary mode.
1571   if (&llvm::outs() == &Out)
1572     sys::Program::ChangeStdoutToBinary();
1573
1574   // Write the generated bitstream to "Out".
1575   Out.write((char*)&Buffer.front(), Buffer.size());
1576
1577   // Make sure it hits disk now.
1578   Out.flush();
1579 }
1580
1581 /// WriteBitcodeToStream - Write the specified module to the specified output
1582 /// stream.
1583 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1584   // If this is darwin, emit a file header and trailer if needed.
1585   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1586   if (isDarwin)
1587     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1588
1589   // Emit the file header.
1590   Stream.Emit((unsigned)'B', 8);
1591   Stream.Emit((unsigned)'C', 8);
1592   Stream.Emit(0x0, 4);
1593   Stream.Emit(0xC, 4);
1594   Stream.Emit(0xE, 4);
1595   Stream.Emit(0xD, 4);
1596
1597   // Emit the module.
1598   WriteModule(M, Stream);
1599
1600   if (isDarwin)
1601     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1602 }