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 (!N->isFunctionLocal()) {
 503         if (!StartedMetadataBlock) {
 504           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 505           StartedMetadataBlock = true;
 506         }
 507         WriteMDNode(N, VE, Stream, Record);
 508       }
 509     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 510       if (!StartedMetadataBlock)  {
 511         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 512
 513         // Abbrev for METADATA_STRING.
 514         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 515         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 516         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 517         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 518         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 519         StartedMetadataBlock = true;
 520       }
 521
 522       // Code: [strchar x N]
 523       Record.append(MDS->begin(), MDS->end());
 524
 525       // Emit the finished record.
 526       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 527       Record.clear();
 528     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 529       if (!StartedMetadataBlock)  {
 530         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 531         StartedMetadataBlock = true;
 532       }
 533
 534       // Write name.
 535       StringRef Str = NMD->getName();
 536       for (unsigned i = 0, e = Str.size(); i != e; ++i)
 537         Record.push_back(Str[i]);
 538       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 539       Record.clear();
 540
 541       // Write named metadata operands.
 542       for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
 543         if (NMD->getOperand(i))
 544           Record.push_back(VE.getValueID(NMD->getOperand(i)));
 545         else
 546           Record.push_back(~0U);
 547       }
 548       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 549       Record.clear();
 550     }
 551   }
 552
 553   if (StartedMetadataBlock)
 554     Stream.ExitBlock();
 555 }
 556
 557 static void WriteFunctionLocalMetadata(const Function &F,
 558                                        const ValueEnumerator &VE,
 559                                        BitstreamWriter &Stream) {
 560   bool StartedMetadataBlock = false;
 561   SmallVector<uint64_t, 64> Record;
 562   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 563
 564   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 565     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first))
 566       if (N->getFunction() == &F) {
 567         if (!StartedMetadataBlock) {
 568           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 569           StartedMetadataBlock = true;
 570         }
 571         WriteMDNode(N, VE, Stream, Record);
 572       }
 573
 574   if (StartedMetadataBlock)
 575     Stream.ExitBlock();
 576 }
 577
 578 static void WriteMetadataAttachment(const Function &F,
 579                                     const ValueEnumerator &VE,
 580                                     BitstreamWriter &Stream) {
 581   bool StartedMetadataBlock = false;
 582   SmallVector<uint64_t, 64> Record;
 583
 584   // Write metadata attachments
 585   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 586   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 587
 588   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 589     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 590          I != E; ++I) {
 591       MDs.clear();
 592       I->getAllMetadata(MDs);
 593
 594       // If no metadata, ignore instruction.
 595       if (MDs.empty()) continue;
 596
 597       Record.push_back(VE.getInstructionID(I));
 598
 599       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 600         Record.push_back(MDs[i].first);
 601         Record.push_back(VE.getValueID(MDs[i].second));
 602       }
 603       if (!StartedMetadataBlock)  {
 604         Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 605         StartedMetadataBlock = true;
 606       }
 607       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 608       Record.clear();
 609     }
 610
 611   if (StartedMetadataBlock)
 612     Stream.ExitBlock();
 613 }
 614
 615 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 616   SmallVector<uint64_t, 64> Record;
 617
 618   // Write metadata kinds
 619   // METADATA_KIND - [n x [id, name]]
 620   SmallVector<StringRef, 4> Names;
 621   M->getMDKindNames(Names);
 622
 623   assert(Names[0] == "" && "MDKind #0 is invalid");
 624   if (Names.size() == 1) return;
 625
 626   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 627
 628   for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
 629     Record.push_back(MDKindID);
 630     StringRef KName = Names[MDKindID];
 631     Record.append(KName.begin(), KName.end());
 632
 633     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 634     Record.clear();
 635   }
 636
 637   Stream.ExitBlock();
 638 }
 639
 640 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 641                            const ValueEnumerator &VE,
 642                            BitstreamWriter &Stream, bool isGlobal) {
 643   if (FirstVal == LastVal) return;
 644
 645   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 646
 647   unsigned AggregateAbbrev = 0;
 648   unsigned String8Abbrev = 0;
 649   unsigned CString7Abbrev = 0;
 650   unsigned CString6Abbrev = 0;
 651   // If this is a constant pool for the module, emit module-specific abbrevs.
 652   if (isGlobal) {
 653     // Abbrev for CST_CODE_AGGREGATE.
 654     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 655     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 658     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 659
 660     // Abbrev for CST_CODE_STRING.
 661     Abbv = new BitCodeAbbrev();
 662     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 665     String8Abbrev = Stream.EmitAbbrev(Abbv);
 666     // Abbrev for CST_CODE_CSTRING.
 667     Abbv = new BitCodeAbbrev();
 668     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 671     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 672     // Abbrev for CST_CODE_CSTRING.
 673     Abbv = new BitCodeAbbrev();
 674     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 677     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 678   }
 679
 680   SmallVector<uint64_t, 64> Record;
 681
 682   const ValueEnumerator::ValueList &Vals = VE.getValues();
 683   const Type *LastTy = 0;
 684   for (unsigned i = FirstVal; i != LastVal; ++i) {
 685     const Value *V = Vals[i].first;
 686     // If we need to switch types, do so now.
 687     if (V->getType() != LastTy) {
 688       LastTy = V->getType();
 689       Record.push_back(VE.getTypeID(LastTy));
 690       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 691                         CONSTANTS_SETTYPE_ABBREV);
 692       Record.clear();
 693     }
 694
 695     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 696       Record.push_back(unsigned(IA->hasSideEffects()) |
 697                        unsigned(IA->isAlignStack()) << 1);
 698
 699       // Add the asm string.
 700       const std::string &AsmStr = IA->getAsmString();
 701       Record.push_back(AsmStr.size());
 702       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 703         Record.push_back(AsmStr[i]);
 704
 705       // Add the constraint string.
 706       const std::string &ConstraintStr = IA->getConstraintString();
 707       Record.push_back(ConstraintStr.size());
 708       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 709         Record.push_back(ConstraintStr[i]);
 710       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 711       Record.clear();
 712       continue;
 713     }
 714     const Constant *C = cast<Constant>(V);
 715     unsigned Code = -1U;
 716     unsigned AbbrevToUse = 0;
 717     if (C->isNullValue()) {
 718       Code = bitc::CST_CODE_NULL;
 719     } else if (isa<UndefValue>(C)) {
 720       Code = bitc::CST_CODE_UNDEF;
 721     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 722       if (IV->getBitWidth() <= 64) {
 723         int64_t V = IV->getSExtValue();
 724         if (V >= 0)
 725           Record.push_back(V << 1);
 726         else
 727           Record.push_back((-V << 1) | 1);
 728         Code = bitc::CST_CODE_INTEGER;
 729         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 730       } else {                             // Wide integers, > 64 bits in size.
 731         // We have an arbitrary precision integer value to write whose
 732         // bit width is > 64. However, in canonical unsigned integer
 733         // format it is likely that the high bits are going to be zero.
 734         // So, we only write the number of active words.
 735         unsigned NWords = IV->getValue().getActiveWords();
 736         const uint64_t *RawWords = IV->getValue().getRawData();
 737         for (unsigned i = 0; i != NWords; ++i) {
 738           int64_t V = RawWords[i];
 739           if (V >= 0)
 740             Record.push_back(V << 1);
 741           else
 742             Record.push_back((-V << 1) | 1);
 743         }
 744         Code = bitc::CST_CODE_WIDE_INTEGER;
 745       }
 746     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 747       Code = bitc::CST_CODE_FLOAT;
 748       const Type *Ty = CFP->getType();
 749       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 750         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 751       } else if (Ty->isX86_FP80Ty()) {
 752         // api needed to prevent premature destruction
 753         // bits are not in the same order as a normal i80 APInt, compensate.
 754         APInt api = CFP->getValueAPF().bitcastToAPInt();
 755         const uint64_t *p = api.getRawData();
 756         Record.push_back((p[1] << 48) | (p[0] >> 16));
 757         Record.push_back(p[0] & 0xffffLL);
 758       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 759         APInt api = CFP->getValueAPF().bitcastToAPInt();
 760         const uint64_t *p = api.getRawData();
 761         Record.push_back(p[0]);
 762         Record.push_back(p[1]);
 763       } else {
 764         assert (0 && "Unknown FP type!");
 765       }
 766     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 767       const ConstantArray *CA = cast<ConstantArray>(C);
 768       // Emit constant strings specially.
 769       unsigned NumOps = CA->getNumOperands();
 770       // If this is a null-terminated string, use the denser CSTRING encoding.
 771       if (CA->getOperand(NumOps-1)->isNullValue()) {
 772         Code = bitc::CST_CODE_CSTRING;
 773         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 774       } else {
 775         Code = bitc::CST_CODE_STRING;
 776         AbbrevToUse = String8Abbrev;
 777       }
 778       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 779       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 780       for (unsigned i = 0; i != NumOps; ++i) {
 781         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 782         Record.push_back(V);
 783         isCStr7 &= (V & 128) == 0;
 784         if (isCStrChar6)
 785           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 786       }
 787
 788       if (isCStrChar6)
 789         AbbrevToUse = CString6Abbrev;
 790       else if (isCStr7)
 791         AbbrevToUse = CString7Abbrev;
 792     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 793                isa<ConstantVector>(V)) {
 794       Code = bitc::CST_CODE_AGGREGATE;
 795       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 796         Record.push_back(VE.getValueID(C->getOperand(i)));
 797       AbbrevToUse = AggregateAbbrev;
 798     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 799       switch (CE->getOpcode()) {
 800       default:
 801         if (Instruction::isCast(CE->getOpcode())) {
 802           Code = bitc::CST_CODE_CE_CAST;
 803           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 804           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 805           Record.push_back(VE.getValueID(C->getOperand(0)));
 806           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 807         } else {
 808           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 809           Code = bitc::CST_CODE_CE_BINOP;
 810           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 811           Record.push_back(VE.getValueID(C->getOperand(0)));
 812           Record.push_back(VE.getValueID(C->getOperand(1)));
 813           uint64_t Flags = GetOptimizationFlags(CE);
 814           if (Flags != 0)
 815             Record.push_back(Flags);
 816         }
 817         break;
 818       case Instruction::GetElementPtr:
 819         Code = bitc::CST_CODE_CE_GEP;
 820         if (cast<GEPOperator>(C)->isInBounds())
 821           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 822         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 823           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 824           Record.push_back(VE.getValueID(C->getOperand(i)));
 825         }
 826         break;
 827       case Instruction::Select:
 828         Code = bitc::CST_CODE_CE_SELECT;
 829         Record.push_back(VE.getValueID(C->getOperand(0)));
 830         Record.push_back(VE.getValueID(C->getOperand(1)));
 831         Record.push_back(VE.getValueID(C->getOperand(2)));
 832         break;
 833       case Instruction::ExtractElement:
 834         Code = bitc::CST_CODE_CE_EXTRACTELT;
 835         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 836         Record.push_back(VE.getValueID(C->getOperand(0)));
 837         Record.push_back(VE.getValueID(C->getOperand(1)));
 838         break;
 839       case Instruction::InsertElement:
 840         Code = bitc::CST_CODE_CE_INSERTELT;
 841         Record.push_back(VE.getValueID(C->getOperand(0)));
 842         Record.push_back(VE.getValueID(C->getOperand(1)));
 843         Record.push_back(VE.getValueID(C->getOperand(2)));
 844         break;
 845       case Instruction::ShuffleVector:
 846         // If the return type and argument types are the same, this is a
 847         // standard shufflevector instruction.  If the types are different,
 848         // then the shuffle is widening or truncating the input vectors, and
 849         // the argument type must also be encoded.
 850         if (C->getType() == C->getOperand(0)->getType()) {
 851           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 852         } else {
 853           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 854           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 855         }
 856         Record.push_back(VE.getValueID(C->getOperand(0)));
 857         Record.push_back(VE.getValueID(C->getOperand(1)));
 858         Record.push_back(VE.getValueID(C->getOperand(2)));
 859         break;
 860       case Instruction::ICmp:
 861       case Instruction::FCmp:
 862         Code = bitc::CST_CODE_CE_CMP;
 863         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 864         Record.push_back(VE.getValueID(C->getOperand(0)));
 865         Record.push_back(VE.getValueID(C->getOperand(1)));
 866         Record.push_back(CE->getPredicate());
 867         break;
 868       }
 869     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 870       assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
 871              "Malformed blockaddress");
 872       Code = bitc::CST_CODE_BLOCKADDRESS;
 873       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 874       Record.push_back(VE.getValueID(BA->getFunction()));
 875       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 876     } else {
 877       llvm_unreachable("Unknown constant!");
 878     }
 879     Stream.EmitRecord(Code, Record, AbbrevToUse);
 880     Record.clear();
 881   }
 882
 883   Stream.ExitBlock();
 884 }
 885
 886 static void WriteModuleConstants(const ValueEnumerator &VE,
 887                                  BitstreamWriter &Stream) {
 888   const ValueEnumerator::ValueList &Vals = VE.getValues();
 889
 890   // Find the first constant to emit, which is the first non-globalvalue value.
 891   // We know globalvalues have been emitted by WriteModuleInfo.
 892   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 893     if (!isa<GlobalValue>(Vals[i].first)) {
 894       WriteConstants(i, Vals.size(), VE, Stream, true);
 895       return;
 896     }
 897   }
 898 }
 899
 900 /// PushValueAndType - The file has to encode both the value and type id for
 901 /// many values, because we need to know what type to create for forward
 902 /// references.  However, most operands are not forward references, so this type
 903 /// field is not needed.
 904 ///
 905 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 906 /// instruction ID, then it is a forward reference, and it also includes the
 907 /// type ID.
 908 static bool PushValueAndType(const Value *V, unsigned InstID,
 909                              SmallVector<unsigned, 64> &Vals,
 910                              ValueEnumerator &VE) {
 911   unsigned ValID = VE.getValueID(V);
 912   Vals.push_back(ValID);
 913   if (ValID >= InstID) {
 914     Vals.push_back(VE.getTypeID(V->getType()));
 915     return true;
 916   }
 917   return false;
 918 }
 919
 920 /// WriteInstruction - Emit an instruction to the specified stream.
 921 static void WriteInstruction(const Instruction &I, unsigned InstID,
 922                              ValueEnumerator &VE, BitstreamWriter &Stream,
 923                              SmallVector<unsigned, 64> &Vals) {
 924   unsigned Code = 0;
 925   unsigned AbbrevToUse = 0;
 926   VE.setInstructionID(&I);
 927   switch (I.getOpcode()) {
 928   default:
 929     if (Instruction::isCast(I.getOpcode())) {
 930       Code = bitc::FUNC_CODE_INST_CAST;
 931       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 932         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 933       Vals.push_back(VE.getTypeID(I.getType()));
 934       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 935     } else {
 936       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 937       Code = bitc::FUNC_CODE_INST_BINOP;
 938       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 939         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 940       Vals.push_back(VE.getValueID(I.getOperand(1)));
 941       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 942       uint64_t Flags = GetOptimizationFlags(&I);
 943       if (Flags != 0) {
 944         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 945           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 946         Vals.push_back(Flags);
 947       }
 948     }
 949     break;
 950
 951   case Instruction::GetElementPtr:
 952     Code = bitc::FUNC_CODE_INST_GEP;
 953     if (cast<GEPOperator>(&I)->isInBounds())
 954       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 955     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 956       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 957     break;
 958   case Instruction::ExtractValue: {
 959     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 960     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 961     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 962     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 963       Vals.push_back(*i);
 964     break;
 965   }
 966   case Instruction::InsertValue: {
 967     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 968     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 969     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 970     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 971     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 972       Vals.push_back(*i);
 973     break;
 974   }
 975   case Instruction::Select:
 976     Code = bitc::FUNC_CODE_INST_VSELECT;
 977     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 978     Vals.push_back(VE.getValueID(I.getOperand(2)));
 979     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 980     break;
 981   case Instruction::ExtractElement:
 982     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 983     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 984     Vals.push_back(VE.getValueID(I.getOperand(1)));
 985     break;
 986   case Instruction::InsertElement:
 987     Code = bitc::FUNC_CODE_INST_INSERTELT;
 988     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 989     Vals.push_back(VE.getValueID(I.getOperand(1)));
 990     Vals.push_back(VE.getValueID(I.getOperand(2)));
 991     break;
 992   case Instruction::ShuffleVector:
 993     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 994     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 995     Vals.push_back(VE.getValueID(I.getOperand(1)));
 996     Vals.push_back(VE.getValueID(I.getOperand(2)));
 997     break;
 998   case Instruction::ICmp:
 999   case Instruction::FCmp:
1000     // compare returning Int1Ty or vector of Int1Ty
1001     Code = bitc::FUNC_CODE_INST_CMP2;
1002     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1003     Vals.push_back(VE.getValueID(I.getOperand(1)));
1004     Vals.push_back(cast<CmpInst>(I).getPredicate());
1005     break;
1006
1007   case Instruction::Ret:
1008     {
1009       Code = bitc::FUNC_CODE_INST_RET;
1010       unsigned NumOperands = I.getNumOperands();
1011       if (NumOperands == 0)
1012         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1013       else if (NumOperands == 1) {
1014         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1015           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1016       } else {
1017         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1018           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1019       }
1020     }
1021     break;
1022   case Instruction::Br:
1023     {
1024       Code = bitc::FUNC_CODE_INST_BR;
1025       BranchInst &II = cast<BranchInst>(I);
1026       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1027       if (II.isConditional()) {
1028         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1029         Vals.push_back(VE.getValueID(II.getCondition()));
1030       }
1031     }
1032     break;
1033   case Instruction::Switch:
1034     Code = bitc::FUNC_CODE_INST_SWITCH;
1035     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1036     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1037       Vals.push_back(VE.getValueID(I.getOperand(i)));
1038     break;
1039   case Instruction::IndirectBr:
1040     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1041     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1042     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1043       Vals.push_back(VE.getValueID(I.getOperand(i)));
1044     break;
1045
1046   case Instruction::Invoke: {
1047     const InvokeInst *II = cast<InvokeInst>(&I);
1048     const Value *Callee(II->getCalledValue());
1049     const PointerType *PTy = cast<PointerType>(Callee->getType());
1050     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1051     Code = bitc::FUNC_CODE_INST_INVOKE;
1052
1053     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1054     Vals.push_back(II->getCallingConv());
1055     Vals.push_back(VE.getValueID(II->getNormalDest()));
1056     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1057     PushValueAndType(Callee, InstID, Vals, VE);
1058
1059     // Emit value #'s for the fixed parameters.
1060     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1061       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1062
1063     // Emit type/value pairs for varargs params.
1064     if (FTy->isVarArg()) {
1065       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1066            i != e; ++i)
1067         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1068     }
1069     break;
1070   }
1071   case Instruction::Unwind:
1072     Code = bitc::FUNC_CODE_INST_UNWIND;
1073     break;
1074   case Instruction::Unreachable:
1075     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1076     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1077     break;
1078
1079   case Instruction::PHI:
1080     Code = bitc::FUNC_CODE_INST_PHI;
1081     Vals.push_back(VE.getTypeID(I.getType()));
1082     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1083       Vals.push_back(VE.getValueID(I.getOperand(i)));
1084     break;
1085
1086   case Instruction::Alloca:
1087     Code = bitc::FUNC_CODE_INST_ALLOCA;
1088     Vals.push_back(VE.getTypeID(I.getType()));
1089     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1090     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1091     break;
1092
1093   case Instruction::Load:
1094     Code = bitc::FUNC_CODE_INST_LOAD;
1095     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1096       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1097
1098     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1099     Vals.push_back(cast<LoadInst>(I).isVolatile());
1100     break;
1101   case Instruction::Store:
1102     Code = bitc::FUNC_CODE_INST_STORE2;
1103     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1104     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1105     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1106     Vals.push_back(cast<StoreInst>(I).isVolatile());
1107     break;
1108   case Instruction::Call: {
1109     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1110     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1111
1112     Code = bitc::FUNC_CODE_INST_CALL;
1113
1114     const CallInst *CI = cast<CallInst>(&I);
1115     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1116     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1117     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1118
1119     // Emit value #'s for the fixed parameters.
1120     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1121       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1122
1123     // Emit type/value pairs for varargs params.
1124     if (FTy->isVarArg()) {
1125       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1126       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1127            i != e; ++i)
1128         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1129     }
1130     break;
1131   }
1132   case Instruction::VAArg:
1133     Code = bitc::FUNC_CODE_INST_VAARG;
1134     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1135     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1136     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1137     break;
1138   }
1139
1140   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1141   Vals.clear();
1142 }
1143
1144 // Emit names for globals/functions etc.
1145 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1146                                   const ValueEnumerator &VE,
1147                                   BitstreamWriter &Stream) {
1148   if (VST.empty()) return;
1149   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1150
1151   // FIXME: Set up the abbrev, we know how many values there are!
1152   // FIXME: We know if the type names can use 7-bit ascii.
1153   SmallVector<unsigned, 64> NameVals;
1154
1155   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1156        SI != SE; ++SI) {
1157
1158     const ValueName &Name = *SI;
1159
1160     // Figure out the encoding to use for the name.
1161     bool is7Bit = true;
1162     bool isChar6 = true;
1163     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1164          C != E; ++C) {
1165       if (isChar6)
1166         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1167       if ((unsigned char)*C & 128) {
1168         is7Bit = false;
1169         break;  // don't bother scanning the rest.
1170       }
1171     }
1172
1173     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1174
1175     // VST_ENTRY:   [valueid, namechar x N]
1176     // VST_BBENTRY: [bbid, namechar x N]
1177     unsigned Code;
1178     if (isa<BasicBlock>(SI->getValue())) {
1179       Code = bitc::VST_CODE_BBENTRY;
1180       if (isChar6)
1181         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1182     } else {
1183       Code = bitc::VST_CODE_ENTRY;
1184       if (isChar6)
1185         AbbrevToUse = VST_ENTRY_6_ABBREV;
1186       else if (is7Bit)
1187         AbbrevToUse = VST_ENTRY_7_ABBREV;
1188     }
1189
1190     NameVals.push_back(VE.getValueID(SI->getValue()));
1191     for (const char *P = Name.getKeyData(),
1192          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1193       NameVals.push_back((unsigned char)*P);
1194
1195     // Emit the finished record.
1196     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1197     NameVals.clear();
1198   }
1199   Stream.ExitBlock();
1200 }
1201
1202 /// WriteFunction - Emit a function body to the module stream.
1203 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1204                           BitstreamWriter &Stream) {
1205   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1206   VE.incorporateFunction(F);
1207
1208   SmallVector<unsigned, 64> Vals;
1209
1210   // Emit the number of basic blocks, so the reader can create them ahead of
1211   // time.
1212   Vals.push_back(VE.getBasicBlocks().size());
1213   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1214   Vals.clear();
1215
1216   // If there are function-local constants, emit them now.
1217   unsigned CstStart, CstEnd;
1218   VE.getFunctionConstantRange(CstStart, CstEnd);
1219   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1220
1221   // If there is function-local metadata, emit it now.
1222   WriteFunctionLocalMetadata(F, VE, Stream);
1223
1224   // Keep a running idea of what the instruction ID is.
1225   unsigned InstID = CstEnd;
1226
1227   // Finally, emit all the instructions, in order.
1228   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1229     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1230          I != E; ++I) {
1231       WriteInstruction(*I, InstID, VE, Stream, Vals);
1232       if (!I->getType()->isVoidTy())
1233         ++InstID;
1234     }
1235
1236   // Emit names for all the instructions etc.
1237   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1238
1239   WriteMetadataAttachment(F, VE, Stream);
1240   VE.purgeFunction();
1241   Stream.ExitBlock();
1242 }
1243
1244 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1245 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1246                                  const ValueEnumerator &VE,
1247                                  BitstreamWriter &Stream) {
1248   if (TST.empty()) return;
1249
1250   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1251
1252   // 7-bit fixed width VST_CODE_ENTRY strings.
1253   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1254   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1255   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1256                             Log2_32_Ceil(VE.getTypes().size()+1)));
1257   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1258   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1259   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1260
1261   SmallVector<unsigned, 64> NameVals;
1262
1263   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1264        TI != TE; ++TI) {
1265     // TST_ENTRY: [typeid, namechar x N]
1266     NameVals.push_back(VE.getTypeID(TI->second));
1267
1268     const std::string &Str = TI->first;
1269     bool is7Bit = true;
1270     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1271       NameVals.push_back((unsigned char)Str[i]);
1272       if (Str[i] & 128)
1273         is7Bit = false;
1274     }
1275
1276     // Emit the finished record.
1277     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1278     NameVals.clear();
1279   }
1280
1281   Stream.ExitBlock();
1282 }
1283
1284 // Emit blockinfo, which defines the standard abbreviations etc.
1285 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1286   // We only want to emit block info records for blocks that have multiple
1287   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1288   // blocks can defined their abbrevs inline.
1289   Stream.EnterBlockInfoBlock(2);
1290
1291   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1292     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1297     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1298                                    Abbv) != VST_ENTRY_8_ABBREV)
1299       llvm_unreachable("Unexpected abbrev ordering!");
1300   }
1301
1302   { // 7-bit fixed width VST_ENTRY strings.
1303     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1304     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1308     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1309                                    Abbv) != VST_ENTRY_7_ABBREV)
1310       llvm_unreachable("Unexpected abbrev ordering!");
1311   }
1312   { // 6-bit char6 VST_ENTRY strings.
1313     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1314     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1318     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1319                                    Abbv) != VST_ENTRY_6_ABBREV)
1320       llvm_unreachable("Unexpected abbrev ordering!");
1321   }
1322   { // 6-bit char6 VST_BBENTRY strings.
1323     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1324     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1325     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1328     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1329                                    Abbv) != VST_BBENTRY_6_ABBREV)
1330       llvm_unreachable("Unexpected abbrev ordering!");
1331   }
1332
1333
1334
1335   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1336     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1337     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1339                               Log2_32_Ceil(VE.getTypes().size()+1)));
1340     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1341                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1342       llvm_unreachable("Unexpected abbrev ordering!");
1343   }
1344
1345   { // INTEGER abbrev for CONSTANTS_BLOCK.
1346     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1347     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1349     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1350                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1351       llvm_unreachable("Unexpected abbrev ordering!");
1352   }
1353
1354   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1355     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1356     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1359                               Log2_32_Ceil(VE.getTypes().size()+1)));
1360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1361
1362     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1363                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1364       llvm_unreachable("Unexpected abbrev ordering!");
1365   }
1366   { // NULL abbrev for CONSTANTS_BLOCK.
1367     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1368     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1369     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1370                                    Abbv) != CONSTANTS_NULL_Abbrev)
1371       llvm_unreachable("Unexpected abbrev ordering!");
1372   }
1373
1374   // FIXME: This should only use space for first class types!
1375
1376   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1377     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1378     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1382     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1383                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1384       llvm_unreachable("Unexpected abbrev ordering!");
1385   }
1386   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1387     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1388     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1390     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1391     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1392     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1393                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1394       llvm_unreachable("Unexpected abbrev ordering!");
1395   }
1396   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1397     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1398     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1399     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1400     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1402     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1403     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1404                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1405       llvm_unreachable("Unexpected abbrev ordering!");
1406   }
1407   { // INST_CAST abbrev for FUNCTION_BLOCK.
1408     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1409     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1411     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1412                               Log2_32_Ceil(VE.getTypes().size()+1)));
1413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1414     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1415                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1416       llvm_unreachable("Unexpected abbrev ordering!");
1417   }
1418
1419   { // INST_RET abbrev for FUNCTION_BLOCK.
1420     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1421     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1422     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1423                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1424       llvm_unreachable("Unexpected abbrev ordering!");
1425   }
1426   { // INST_RET abbrev for FUNCTION_BLOCK.
1427     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1428     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1430     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1431                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1432       llvm_unreachable("Unexpected abbrev ordering!");
1433   }
1434   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1435     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1436     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1437     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1438                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1439       llvm_unreachable("Unexpected abbrev ordering!");
1440   }
1441
1442   Stream.ExitBlock();
1443 }
1444
1445
1446 /// WriteModule - Emit the specified module to the bitstream.
1447 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1448   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1449
1450   // Emit the version number if it is non-zero.
1451   if (CurVersion) {
1452     SmallVector<unsigned, 1> Vals;
1453     Vals.push_back(CurVersion);
1454     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1455   }
1456
1457   // Analyze the module, enumerating globals, functions, etc.
1458   ValueEnumerator VE(M);
1459
1460   // Emit blockinfo, which defines the standard abbreviations etc.
1461   WriteBlockInfo(VE, Stream);
1462
1463   // Emit information about parameter attributes.
1464   WriteAttributeTable(VE, Stream);
1465
1466   // Emit information describing all of the types in the module.
1467   WriteTypeTable(VE, Stream);
1468
1469   // Emit top-level description of module, including target triple, inline asm,
1470   // descriptors for global variables, and function prototype info.
1471   WriteModuleInfo(M, VE, Stream);
1472
1473   // Emit constants.
1474   WriteModuleConstants(VE, Stream);
1475
1476   // Emit metadata.
1477   WriteModuleMetadata(VE, Stream);
1478
1479   // Emit function bodies.
1480   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1481     if (!I->isDeclaration())
1482       WriteFunction(*I, VE, Stream);
1483
1484   // Emit metadata.
1485   WriteModuleMetadataStore(M, Stream);
1486
1487   // Emit the type symbol table information.
1488   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1489
1490   // Emit names for globals/functions etc.
1491   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1492
1493   Stream.ExitBlock();
1494 }
1495
1496 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1497 /// header and trailer to make it compatible with the system archiver.  To do
1498 /// this we emit the following header, and then emit a trailer that pads the
1499 /// file out to be a multiple of 16 bytes.
1500 ///
1501 /// struct bc_header {
1502 ///   uint32_t Magic;         // 0x0B17C0DE
1503 ///   uint32_t Version;       // Version, currently always 0.
1504 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1505 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1506 ///   uint32_t CPUType;       // CPU specifier.
1507 ///   ... potentially more later ...
1508 /// };
1509 enum {
1510   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1511   DarwinBCHeaderSize = 5*4
1512 };
1513
1514 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1515                                const std::string &TT) {
1516   unsigned CPUType = ~0U;
1517
1518   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1519   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1520   // specific constants here because they are implicitly part of the Darwin ABI.
1521   enum {
1522     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1523     DARWIN_CPU_TYPE_X86        = 7,
1524     DARWIN_CPU_TYPE_POWERPC    = 18
1525   };
1526
1527   if (TT.find("x86_64-") == 0)
1528     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1529   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1530            TT[4] == '-' && TT[1] - '3' < 6)
1531     CPUType = DARWIN_CPU_TYPE_X86;
1532   else if (TT.find("powerpc-") == 0)
1533     CPUType = DARWIN_CPU_TYPE_POWERPC;
1534   else if (TT.find("powerpc64-") == 0)
1535     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1536
1537   // Traditional Bitcode starts after header.
1538   unsigned BCOffset = DarwinBCHeaderSize;
1539
1540   Stream.Emit(0x0B17C0DE, 32);
1541   Stream.Emit(0         , 32);  // Version.
1542   Stream.Emit(BCOffset  , 32);
1543   Stream.Emit(0         , 32);  // Filled in later.
1544   Stream.Emit(CPUType   , 32);
1545 }
1546
1547 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1548 /// finalize the header.
1549 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1550   // Update the size field in the header.
1551   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1552
1553   // If the file is not a multiple of 16 bytes, insert dummy padding.
1554   while (BufferSize & 15) {
1555     Stream.Emit(0, 8);
1556     ++BufferSize;
1557   }
1558 }
1559
1560
1561 /// WriteBitcodeToFile - Write the specified module to the specified output
1562 /// stream.
1563 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1564   std::vector<unsigned char> Buffer;
1565   BitstreamWriter Stream(Buffer);
1566
1567   Buffer.reserve(256*1024);
1568
1569   WriteBitcodeToStream( M, Stream );
1570
1571   // If writing to stdout, set binary mode.
1572   if (&llvm::outs() == &Out)
1573     sys::Program::ChangeStdoutToBinary();
1574
1575   // Write the generated bitstream to "Out".
1576   Out.write((char*)&Buffer.front(), Buffer.size());
1577
1578   // Make sure it hits disk now.
1579   Out.flush();
1580 }
1581
1582 /// WriteBitcodeToStream - Write the specified module to the specified output
1583 /// stream.
1584 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1585   // If this is darwin, emit a file header and trailer if needed.
1586   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1587   if (isDarwin)
1588     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1589
1590   // Emit the file header.
1591   Stream.Emit((unsigned)'B', 8);
1592   Stream.Emit((unsigned)'C', 8);
1593   Stream.Emit(0x0, 4);
1594   Stream.Emit(0xC, 4);
1595   Stream.Emit(0xE, 4);
1596   Stream.Emit(0xD, 4);
1597
1598   // Emit the module.
1599   WriteModule(M, Stream);
1600
1601   if (isDarwin)
1602     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1603 }