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