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