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/LLVMContext.h"
  23 #include "llvm/Metadata.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/Operator.h"
  26 #include "llvm/TypeSymbolTable.h"
  27 #include "llvm/ValueSymbolTable.h"
  28 #include "llvm/Support/ErrorHandling.h"
  29 #include "llvm/Support/MathExtras.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include "llvm/System/Program.h"
  32 using namespace llvm;
  33
  34 /// These are manifest constants used by the bitcode writer. They do not need to
  35 /// be kept in sync with the reader, but need to be consistent within this file.
  36 enum {
  37   CurVersion = 0,
  38
  39   // VALUE_SYMTAB_BLOCK abbrev id's.
  40   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  41   VST_ENTRY_7_ABBREV,
  42   VST_ENTRY_6_ABBREV,
  43   VST_BBENTRY_6_ABBREV,
  44
  45   // CONSTANTS_BLOCK abbrev id's.
  46   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  47   CONSTANTS_INTEGER_ABBREV,
  48   CONSTANTS_CE_CAST_Abbrev,
  49   CONSTANTS_NULL_Abbrev,
  50
  51   // FUNCTION_BLOCK abbrev id's.
  52   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  53   FUNCTION_INST_BINOP_ABBREV,
  54   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  55   FUNCTION_INST_CAST_ABBREV,
  56   FUNCTION_INST_RET_VOID_ABBREV,
  57   FUNCTION_INST_RET_VAL_ABBREV,
  58   FUNCTION_INST_UNREACHABLE_ABBREV
  59 };
  60
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   }
  78 }
  79
  80 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  81   switch (Opcode) {
  82   default: llvm_unreachable("Unknown binary instruction!");
  83   case Instruction::Add:
  84   case Instruction::FAdd: return bitc::BINOP_ADD;
  85   case Instruction::Sub:
  86   case Instruction::FSub: return bitc::BINOP_SUB;
  87   case Instruction::Mul:
  88   case Instruction::FMul: return bitc::BINOP_MUL;
  89   case Instruction::UDiv: return bitc::BINOP_UDIV;
  90   case Instruction::FDiv:
  91   case Instruction::SDiv: return bitc::BINOP_SDIV;
  92   case Instruction::URem: return bitc::BINOP_UREM;
  93   case Instruction::FRem:
  94   case Instruction::SRem: return bitc::BINOP_SREM;
  95   case Instruction::Shl:  return bitc::BINOP_SHL;
  96   case Instruction::LShr: return bitc::BINOP_LSHR;
  97   case Instruction::AShr: return bitc::BINOP_ASHR;
  98   case Instruction::And:  return bitc::BINOP_AND;
  99   case Instruction::Or:   return bitc::BINOP_OR;
 100   case Instruction::Xor:  return bitc::BINOP_XOR;
 101   }
 102 }
 103
 104
 105
 106 static void WriteStringRecord(unsigned Code, const std::string &Str,
 107                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 108   SmallVector<unsigned, 64> Vals;
 109
 110   // Code: [strchar x N]
 111   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 112     Vals.push_back(Str[i]);
 113
 114   // Emit the finished record.
 115   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 116 }
 117
 118 // Emit information about parameter attributes.
 119 static void WriteAttributeTable(const ValueEnumerator &VE,
 120                                 BitstreamWriter &Stream) {
 121   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 122   if (Attrs.empty()) return;
 123
 124   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 125
 126   SmallVector<uint64_t, 64> Record;
 127   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 128     const AttrListPtr &A = Attrs[i];
 129     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 130       const AttributeWithIndex &PAWI = A.getSlot(i);
 131       Record.push_back(PAWI.Index);
 132
 133       // FIXME: remove in LLVM 3.0
 134       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 135       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 136       // 11 bits.
 137       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 138       if (PAWI.Attrs & Attribute::Alignment)
 139         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 140       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 141
 142       Record.push_back(FauxAttr);
 143     }
 144
 145     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 146     Record.clear();
 147   }
 148
 149   Stream.ExitBlock();
 150 }
 151
 152 /// WriteTypeTable - Write out the type table for a module.
 153 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 154   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 155
 156   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 157   SmallVector<uint64_t, 64> TypeVals;
 158
 159   // Abbrev for TYPE_CODE_POINTER.
 160   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 161   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 163                             Log2_32_Ceil(VE.getTypes().size()+1)));
 164   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 165   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 166
 167   // Abbrev for TYPE_CODE_FUNCTION.
 168   Abbv = new BitCodeAbbrev();
 169   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 171   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 174                             Log2_32_Ceil(VE.getTypes().size()+1)));
 175   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 176
 177   // Abbrev for TYPE_CODE_STRUCT.
 178   Abbv = new BitCodeAbbrev();
 179   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 183                             Log2_32_Ceil(VE.getTypes().size()+1)));
 184   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 185
 186   // Abbrev for TYPE_CODE_ARRAY.
 187   Abbv = new BitCodeAbbrev();
 188   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 191                             Log2_32_Ceil(VE.getTypes().size()+1)));
 192   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 193
 194   // Emit an entry count so the reader can reserve space.
 195   TypeVals.push_back(TypeList.size());
 196   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 197   TypeVals.clear();
 198
 199   // Loop over all of the types, emitting each in turn.
 200   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 201     const Type *T = TypeList[i].first;
 202     int AbbrevToUse = 0;
 203     unsigned Code = 0;
 204
 205     switch (T->getTypeID()) {
 206     default: llvm_unreachable("Unknown type!");
 207     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 208     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 209     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 210     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 211     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 212     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 213     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 214     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 215     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 216     case Type::IntegerTyID:
 217       // INTEGER: [width]
 218       Code = bitc::TYPE_CODE_INTEGER;
 219       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 220       break;
 221     case Type::PointerTyID: {
 222       const PointerType *PTy = cast<PointerType>(T);
 223       // POINTER: [pointee type, address space]
 224       Code = bitc::TYPE_CODE_POINTER;
 225       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 226       unsigned AddressSpace = PTy->getAddressSpace();
 227       TypeVals.push_back(AddressSpace);
 228       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 229       break;
 230     }
 231     case Type::FunctionTyID: {
 232       const FunctionType *FT = cast<FunctionType>(T);
 233       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 234       Code = bitc::TYPE_CODE_FUNCTION;
 235       TypeVals.push_back(FT->isVarArg());
 236       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 237       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 238       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 239         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 240       AbbrevToUse = FunctionAbbrev;
 241       break;
 242     }
 243     case Type::StructTyID: {
 244       const StructType *ST = cast<StructType>(T);
 245       // STRUCT: [ispacked, eltty x N]
 246       Code = bitc::TYPE_CODE_STRUCT;
 247       TypeVals.push_back(ST->isPacked());
 248       // Output all of the element types.
 249       for (StructType::element_iterator I = ST->element_begin(),
 250            E = ST->element_end(); I != E; ++I)
 251         TypeVals.push_back(VE.getTypeID(*I));
 252       AbbrevToUse = StructAbbrev;
 253       break;
 254     }
 255     case Type::ArrayTyID: {
 256       const ArrayType *AT = cast<ArrayType>(T);
 257       // ARRAY: [numelts, eltty]
 258       Code = bitc::TYPE_CODE_ARRAY;
 259       TypeVals.push_back(AT->getNumElements());
 260       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 261       AbbrevToUse = ArrayAbbrev;
 262       break;
 263     }
 264     case Type::VectorTyID: {
 265       const VectorType *VT = cast<VectorType>(T);
 266       // VECTOR [numelts, eltty]
 267       Code = bitc::TYPE_CODE_VECTOR;
 268       TypeVals.push_back(VT->getNumElements());
 269       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 270       break;
 271     }
 272     }
 273
 274     // Emit the finished record.
 275     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 276     TypeVals.clear();
 277   }
 278
 279   Stream.ExitBlock();
 280 }
 281
 282 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 283   switch (GV->getLinkage()) {
 284   default: llvm_unreachable("Invalid linkage!");
 285   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 286   case GlobalValue::ExternalLinkage:            return 0;
 287   case GlobalValue::WeakAnyLinkage:             return 1;
 288   case GlobalValue::AppendingLinkage:           return 2;
 289   case GlobalValue::InternalLinkage:            return 3;
 290   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 291   case GlobalValue::DLLImportLinkage:           return 5;
 292   case GlobalValue::DLLExportLinkage:           return 6;
 293   case GlobalValue::ExternalWeakLinkage:        return 7;
 294   case GlobalValue::CommonLinkage:              return 8;
 295   case GlobalValue::PrivateLinkage:             return 9;
 296   case GlobalValue::WeakODRLinkage:             return 10;
 297   case GlobalValue::LinkOnceODRLinkage:         return 11;
 298   case GlobalValue::AvailableExternallyLinkage: return 12;
 299   case GlobalValue::LinkerPrivateLinkage:       return 13;
 300   }
 301 }
 302
 303 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 304   switch (GV->getVisibility()) {
 305   default: llvm_unreachable("Invalid visibility!");
 306   case GlobalValue::DefaultVisibility:   return 0;
 307   case GlobalValue::HiddenVisibility:    return 1;
 308   case GlobalValue::ProtectedVisibility: return 2;
 309   }
 310 }
 311
 312 // Emit top-level description of module, including target triple, inline asm,
 313 // descriptors for global variables, and function prototype info.
 314 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 315                             BitstreamWriter &Stream) {
 316   // Emit the list of dependent libraries for the Module.
 317   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 318     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 319
 320   // Emit various pieces of data attached to a module.
 321   if (!M->getTargetTriple().empty())
 322     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 323                       0/*TODO*/, Stream);
 324   if (!M->getDataLayout().empty())
 325     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 326                       0/*TODO*/, Stream);
 327   if (!M->getModuleInlineAsm().empty())
 328     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 329                       0/*TODO*/, Stream);
 330
 331   // Emit information about sections and GC, computing how many there are. Also
 332   // compute the maximum alignment value.
 333   std::map<std::string, unsigned> SectionMap;
 334   std::map<std::string, unsigned> GCMap;
 335   unsigned MaxAlignment = 0;
 336   unsigned MaxGlobalType = 0;
 337   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 338        GV != E; ++GV) {
 339     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 340     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 341
 342     if (!GV->hasSection()) continue;
 343     // Give section names unique ID's.
 344     unsigned &Entry = SectionMap[GV->getSection()];
 345     if (Entry != 0) continue;
 346     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 347                       0/*TODO*/, Stream);
 348     Entry = SectionMap.size();
 349   }
 350   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 351     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 352     if (F->hasSection()) {
 353       // Give section names unique ID's.
 354       unsigned &Entry = SectionMap[F->getSection()];
 355       if (!Entry) {
 356         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 357                           0/*TODO*/, Stream);
 358         Entry = SectionMap.size();
 359       }
 360     }
 361     if (F->hasGC()) {
 362       // Same for GC names.
 363       unsigned &Entry = GCMap[F->getGC()];
 364       if (!Entry) {
 365         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 366                           0/*TODO*/, Stream);
 367         Entry = GCMap.size();
 368       }
 369     }
 370   }
 371
 372   // Emit abbrev for globals, now that we know # sections and max alignment.
 373   unsigned SimpleGVarAbbrev = 0;
 374   if (!M->global_empty()) {
 375     // Add an abbrev for common globals with no visibility or thread localness.
 376     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 377     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 379                               Log2_32_Ceil(MaxGlobalType+1)));
 380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 383     if (MaxAlignment == 0)                                      // Alignment.
 384       Abbv->Add(BitCodeAbbrevOp(0));
 385     else {
 386       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 387       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 388                                Log2_32_Ceil(MaxEncAlignment+1)));
 389     }
 390     if (SectionMap.empty())                                    // Section.
 391       Abbv->Add(BitCodeAbbrevOp(0));
 392     else
 393       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 394                                Log2_32_Ceil(SectionMap.size()+1)));
 395     // Don't bother emitting vis + thread local.
 396     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 397   }
 398
 399   // Emit the global variable information.
 400   SmallVector<unsigned, 64> Vals;
 401   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 402        GV != E; ++GV) {
 403     unsigned AbbrevToUse = 0;
 404
 405     // GLOBALVAR: [type, isconst, initid,
 406     //             linkage, alignment, section, visibility, threadlocal]
 407     Vals.push_back(VE.getTypeID(GV->getType()));
 408     Vals.push_back(GV->isConstant());
 409     Vals.push_back(GV->isDeclaration() ? 0 :
 410                    (VE.getValueID(GV->getInitializer()) + 1));
 411     Vals.push_back(getEncodedLinkage(GV));
 412     Vals.push_back(Log2_32(GV->getAlignment())+1);
 413     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 414     if (GV->isThreadLocal() ||
 415         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 416       Vals.push_back(getEncodedVisibility(GV));
 417       Vals.push_back(GV->isThreadLocal());
 418     } else {
 419       AbbrevToUse = SimpleGVarAbbrev;
 420     }
 421
 422     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 423     Vals.clear();
 424   }
 425
 426   // Emit the function proto information.
 427   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 428     // FUNCTION:  [type, callingconv, isproto, paramattr,
 429     //             linkage, alignment, section, visibility, gc]
 430     Vals.push_back(VE.getTypeID(F->getType()));
 431     Vals.push_back(F->getCallingConv());
 432     Vals.push_back(F->isDeclaration());
 433     Vals.push_back(getEncodedLinkage(F));
 434     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 435     Vals.push_back(Log2_32(F->getAlignment())+1);
 436     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 437     Vals.push_back(getEncodedVisibility(F));
 438     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 439
 440     unsigned AbbrevToUse = 0;
 441     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 442     Vals.clear();
 443   }
 444
 445
 446   // Emit the alias information.
 447   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 448        AI != E; ++AI) {
 449     Vals.push_back(VE.getTypeID(AI->getType()));
 450     Vals.push_back(VE.getValueID(AI->getAliasee()));
 451     Vals.push_back(getEncodedLinkage(AI));
 452     Vals.push_back(getEncodedVisibility(AI));
 453     unsigned AbbrevToUse = 0;
 454     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 455     Vals.clear();
 456   }
 457 }
 458
 459 static uint64_t GetOptimizationFlags(const Value *V) {
 460   uint64_t Flags = 0;
 461
 462   if (const OverflowingBinaryOperator *OBO =
 463         dyn_cast<OverflowingBinaryOperator>(V)) {
 464     if (OBO->hasNoSignedWrap())
 465       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 466     if (OBO->hasNoUnsignedWrap())
 467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 468   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 469     if (Div->isExact())
 470       Flags |= 1 << bitc::SDIV_EXACT;
 471   }
 472
 473   return Flags;
 474 }
 475
 476 static void WriteMDNode(const MDNode *N,
 477                         const ValueEnumerator &VE,
 478                         BitstreamWriter &Stream,
 479                         SmallVector<uint64_t, 64> &Record) {
 480   for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 481     if (N->getElement(i)) {
 482       Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 483       Record.push_back(VE.getValueID(N->getElement(i)));
 484     } else {
 485       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 486       Record.push_back(0);
 487     }
 488   }
 489   Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
 490   Record.clear();
 491 }
 492
 493 static void WriteModuleMetadata(const ValueEnumerator &VE,
 494                                 BitstreamWriter &Stream) {
 495   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 496   bool StartedMetadataBlock = false;
 497   unsigned MDSAbbrev = 0;
 498   SmallVector<uint64_t, 64> Record;
 499   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 500
 501     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 502       if (!StartedMetadataBlock) {
 503         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 504         StartedMetadataBlock = true;
 505       }
 506       WriteMDNode(N, VE, Stream, Record);
 507     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 508       if (!StartedMetadataBlock)  {
 509         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 510
 511         // Abbrev for METADATA_STRING.
 512         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 513         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 514         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 515         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 516         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 517         StartedMetadataBlock = true;
 518       }
 519
 520       // Code: [strchar x N]
 521       Record.append(MDS->begin(), MDS->end());
 522
 523       // Emit the finished record.
 524       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 525       Record.clear();
 526     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 527       if (!StartedMetadataBlock)  {
 528         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 529         StartedMetadataBlock = true;
 530       }
 531
 532       // Write name.
 533       std::string Str = NMD->getNameStr();
 534       const char *StrBegin = Str.c_str();
 535       for (unsigned i = 0, e = Str.length(); i != e; ++i)
 536         Record.push_back(StrBegin[i]);
 537       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 538       Record.clear();
 539
 540       // Write named metadata elements.
 541       for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
 542         if (NMD->getElement(i))
 543           Record.push_back(VE.getValueID(NMD->getElement(i)));
 544         else
 545           Record.push_back(0);
 546       }
 547       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 548       Record.clear();
 549     }
 550   }
 551
 552   if (StartedMetadataBlock)
 553     Stream.ExitBlock();
 554 }
 555
 556 static void WriteMetadataAttachment(const Function &F,
 557                                     const ValueEnumerator &VE,
 558                                     BitstreamWriter &Stream) {
 559   bool StartedMetadataBlock = false;
 560   SmallVector<uint64_t, 64> Record;
 561
 562   // Write metadata attachments
 563   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 564   MetadataContext &TheMetadata = F.getContext().getMetadata();
 565   typedef SmallVector<std::pair<unsigned, TrackingVH<MDNode> >, 2> MDMapTy;
 566   MDMapTy MDs;
 567   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 568     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 569          I != E; ++I) {
 570       MDs.clear();
 571       TheMetadata.getMDs(I, MDs);
 572       bool RecordedInstruction = false;
 573       for (MDMapTy::const_iterator PI = MDs.begin(), PE = MDs.end();
 574              PI != PE; ++PI) {
 575         if (RecordedInstruction == false) {
 576           Record.push_back(VE.getInstructionID(I));
 577           RecordedInstruction = true;
 578         }
 579         Record.push_back(PI->first);
 580         Record.push_back(VE.getValueID(PI->second));
 581       }
 582       if (!Record.empty()) {
 583         if (!StartedMetadataBlock)  {
 584           Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 585           StartedMetadataBlock = true;
 586         }
 587         Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 588         Record.clear();
 589       }
 590     }
 591
 592   if (StartedMetadataBlock)
 593     Stream.ExitBlock();
 594 }
 595
 596 static void WriteModuleMetadataStore(const Module *M,
 597                                      const ValueEnumerator &VE,
 598                                      BitstreamWriter &Stream) {
 599
 600   bool StartedMetadataBlock = false;
 601   SmallVector<uint64_t, 64> Record;
 602
 603   // Write metadata kinds
 604   // METADATA_KIND - [n x [id, name]]
 605   MetadataContext &TheMetadata = M->getContext().getMetadata();
 606   SmallVector<std::pair<unsigned, StringRef>, 4> Names;
 607   TheMetadata.getHandlerNames(Names);
 608   for (SmallVector<std::pair<unsigned, StringRef>, 4>::iterator
 609          I = Names.begin(),
 610          E = Names.end(); I != E; ++I) {
 611     Record.push_back(I->first);
 612     StringRef KName = I->second;
 613     for (unsigned i = 0, e = KName.size(); i != e; ++i)
 614       Record.push_back(KName[i]);
 615     if (!StartedMetadataBlock)  {
 616       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 617       StartedMetadataBlock = true;
 618     }
 619     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 620     Record.clear();
 621   }
 622
 623   if (StartedMetadataBlock)
 624     Stream.ExitBlock();
 625 }
 626
 627 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 628                            const ValueEnumerator &VE,
 629                            BitstreamWriter &Stream, bool isGlobal) {
 630   if (FirstVal == LastVal) return;
 631
 632   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 633
 634   unsigned AggregateAbbrev = 0;
 635   unsigned String8Abbrev = 0;
 636   unsigned CString7Abbrev = 0;
 637   unsigned CString6Abbrev = 0;
 638   // If this is a constant pool for the module, emit module-specific abbrevs.
 639   if (isGlobal) {
 640     // Abbrev for CST_CODE_AGGREGATE.
 641     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 642     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 645     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 646
 647     // Abbrev for CST_CODE_STRING.
 648     Abbv = new BitCodeAbbrev();
 649     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 650     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 652     String8Abbrev = Stream.EmitAbbrev(Abbv);
 653     // Abbrev for CST_CODE_CSTRING.
 654     Abbv = new BitCodeAbbrev();
 655     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 658     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 659     // Abbrev for CST_CODE_CSTRING.
 660     Abbv = new BitCodeAbbrev();
 661     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 664     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 665   }
 666
 667   SmallVector<uint64_t, 64> Record;
 668
 669   const ValueEnumerator::ValueList &Vals = VE.getValues();
 670   const Type *LastTy = 0;
 671   for (unsigned i = FirstVal; i != LastVal; ++i) {
 672     const Value *V = Vals[i].first;
 673     // If we need to switch types, do so now.
 674     if (V->getType() != LastTy) {
 675       LastTy = V->getType();
 676       Record.push_back(VE.getTypeID(LastTy));
 677       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 678                         CONSTANTS_SETTYPE_ABBREV);
 679       Record.clear();
 680     }
 681
 682     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 683       Record.push_back(unsigned(IA->hasSideEffects()) |
 684                        unsigned(IA->isAlignStack()) << 1);
 685
 686       // Add the asm string.
 687       const std::string &AsmStr = IA->getAsmString();
 688       Record.push_back(AsmStr.size());
 689       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 690         Record.push_back(AsmStr[i]);
 691
 692       // Add the constraint string.
 693       const std::string &ConstraintStr = IA->getConstraintString();
 694       Record.push_back(ConstraintStr.size());
 695       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 696         Record.push_back(ConstraintStr[i]);
 697       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 698       Record.clear();
 699       continue;
 700     }
 701     const Constant *C = cast<Constant>(V);
 702     unsigned Code = -1U;
 703     unsigned AbbrevToUse = 0;
 704     if (C->isNullValue()) {
 705       Code = bitc::CST_CODE_NULL;
 706     } else if (isa<UndefValue>(C)) {
 707       Code = bitc::CST_CODE_UNDEF;
 708     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 709       if (IV->getBitWidth() <= 64) {
 710         int64_t V = IV->getSExtValue();
 711         if (V >= 0)
 712           Record.push_back(V << 1);
 713         else
 714           Record.push_back((-V << 1) | 1);
 715         Code = bitc::CST_CODE_INTEGER;
 716         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 717       } else {                             // Wide integers, > 64 bits in size.
 718         // We have an arbitrary precision integer value to write whose
 719         // bit width is > 64. However, in canonical unsigned integer
 720         // format it is likely that the high bits are going to be zero.
 721         // So, we only write the number of active words.
 722         unsigned NWords = IV->getValue().getActiveWords();
 723         const uint64_t *RawWords = IV->getValue().getRawData();
 724         for (unsigned i = 0; i != NWords; ++i) {
 725           int64_t V = RawWords[i];
 726           if (V >= 0)
 727             Record.push_back(V << 1);
 728           else
 729             Record.push_back((-V << 1) | 1);
 730         }
 731         Code = bitc::CST_CODE_WIDE_INTEGER;
 732       }
 733     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 734       Code = bitc::CST_CODE_FLOAT;
 735       const Type *Ty = CFP->getType();
 736       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 737         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 738       } else if (Ty->isX86_FP80Ty()) {
 739         // api needed to prevent premature destruction
 740         // bits are not in the same order as a normal i80 APInt, compensate.
 741         APInt api = CFP->getValueAPF().bitcastToAPInt();
 742         const uint64_t *p = api.getRawData();
 743         Record.push_back((p[1] << 48) | (p[0] >> 16));
 744         Record.push_back(p[0] & 0xffffLL);
 745       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 746         APInt api = CFP->getValueAPF().bitcastToAPInt();
 747         const uint64_t *p = api.getRawData();
 748         Record.push_back(p[0]);
 749         Record.push_back(p[1]);
 750       } else {
 751         assert (0 && "Unknown FP type!");
 752       }
 753     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 754       const ConstantArray *CA = cast<ConstantArray>(C);
 755       // Emit constant strings specially.
 756       unsigned NumOps = CA->getNumOperands();
 757       // If this is a null-terminated string, use the denser CSTRING encoding.
 758       if (CA->getOperand(NumOps-1)->isNullValue()) {
 759         Code = bitc::CST_CODE_CSTRING;
 760         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 761       } else {
 762         Code = bitc::CST_CODE_STRING;
 763         AbbrevToUse = String8Abbrev;
 764       }
 765       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 766       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 767       for (unsigned i = 0; i != NumOps; ++i) {
 768         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 769         Record.push_back(V);
 770         isCStr7 &= (V & 128) == 0;
 771         if (isCStrChar6)
 772           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 773       }
 774
 775       if (isCStrChar6)
 776         AbbrevToUse = CString6Abbrev;
 777       else if (isCStr7)
 778         AbbrevToUse = CString7Abbrev;
 779     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 780                isa<ConstantVector>(V)) {
 781       Code = bitc::CST_CODE_AGGREGATE;
 782       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 783         Record.push_back(VE.getValueID(C->getOperand(i)));
 784       AbbrevToUse = AggregateAbbrev;
 785     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 786       switch (CE->getOpcode()) {
 787       default:
 788         if (Instruction::isCast(CE->getOpcode())) {
 789           Code = bitc::CST_CODE_CE_CAST;
 790           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 791           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 792           Record.push_back(VE.getValueID(C->getOperand(0)));
 793           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 794         } else {
 795           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 796           Code = bitc::CST_CODE_CE_BINOP;
 797           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 798           Record.push_back(VE.getValueID(C->getOperand(0)));
 799           Record.push_back(VE.getValueID(C->getOperand(1)));
 800           uint64_t Flags = GetOptimizationFlags(CE);
 801           if (Flags != 0)
 802             Record.push_back(Flags);
 803         }
 804         break;
 805       case Instruction::GetElementPtr:
 806         Code = bitc::CST_CODE_CE_GEP;
 807         if (cast<GEPOperator>(C)->isInBounds())
 808           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 809         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 810           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 811           Record.push_back(VE.getValueID(C->getOperand(i)));
 812         }
 813         break;
 814       case Instruction::Select:
 815         Code = bitc::CST_CODE_CE_SELECT;
 816         Record.push_back(VE.getValueID(C->getOperand(0)));
 817         Record.push_back(VE.getValueID(C->getOperand(1)));
 818         Record.push_back(VE.getValueID(C->getOperand(2)));
 819         break;
 820       case Instruction::ExtractElement:
 821         Code = bitc::CST_CODE_CE_EXTRACTELT;
 822         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 823         Record.push_back(VE.getValueID(C->getOperand(0)));
 824         Record.push_back(VE.getValueID(C->getOperand(1)));
 825         break;
 826       case Instruction::InsertElement:
 827         Code = bitc::CST_CODE_CE_INSERTELT;
 828         Record.push_back(VE.getValueID(C->getOperand(0)));
 829         Record.push_back(VE.getValueID(C->getOperand(1)));
 830         Record.push_back(VE.getValueID(C->getOperand(2)));
 831         break;
 832       case Instruction::ShuffleVector:
 833         // If the return type and argument types are the same, this is a
 834         // standard shufflevector instruction.  If the types are different,
 835         // then the shuffle is widening or truncating the input vectors, and
 836         // the argument type must also be encoded.
 837         if (C->getType() == C->getOperand(0)->getType()) {
 838           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 839         } else {
 840           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 841           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 842         }
 843         Record.push_back(VE.getValueID(C->getOperand(0)));
 844         Record.push_back(VE.getValueID(C->getOperand(1)));
 845         Record.push_back(VE.getValueID(C->getOperand(2)));
 846         break;
 847       case Instruction::ICmp:
 848       case Instruction::FCmp:
 849         Code = bitc::CST_CODE_CE_CMP;
 850         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 851         Record.push_back(VE.getValueID(C->getOperand(0)));
 852         Record.push_back(VE.getValueID(C->getOperand(1)));
 853         Record.push_back(CE->getPredicate());
 854         break;
 855       }
 856     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 857       assert((!BA->getBasicBlock() ||
 858               BA->getFunction() == BA->getBasicBlock()->getParent()) &&
 859              "Malformed blockaddress");
 860       Code = bitc::CST_CODE_BLOCKADDRESS;
 861       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 862       Record.push_back(VE.getValueID(BA->getFunction()));
 863       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 864     } else {
 865       llvm_unreachable("Unknown constant!");
 866     }
 867     Stream.EmitRecord(Code, Record, AbbrevToUse);
 868     Record.clear();
 869   }
 870
 871   Stream.ExitBlock();
 872 }
 873
 874 static void WriteModuleConstants(const ValueEnumerator &VE,
 875                                  BitstreamWriter &Stream) {
 876   const ValueEnumerator::ValueList &Vals = VE.getValues();
 877
 878   // Find the first constant to emit, which is the first non-globalvalue value.
 879   // We know globalvalues have been emitted by WriteModuleInfo.
 880   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 881     if (!isa<GlobalValue>(Vals[i].first)) {
 882       WriteConstants(i, Vals.size(), VE, Stream, true);
 883       return;
 884     }
 885   }
 886 }
 887
 888 /// PushValueAndType - The file has to encode both the value and type id for
 889 /// many values, because we need to know what type to create for forward
 890 /// references.  However, most operands are not forward references, so this type
 891 /// field is not needed.
 892 ///
 893 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 894 /// instruction ID, then it is a forward reference, and it also includes the
 895 /// type ID.
 896 static bool PushValueAndType(const Value *V, unsigned InstID,
 897                              SmallVector<unsigned, 64> &Vals,
 898                              ValueEnumerator &VE) {
 899   unsigned ValID = VE.getValueID(V);
 900   Vals.push_back(ValID);
 901   if (ValID >= InstID) {
 902     Vals.push_back(VE.getTypeID(V->getType()));
 903     return true;
 904   }
 905   return false;
 906 }
 907
 908 /// WriteInstruction - Emit an instruction to the specified stream.
 909 static void WriteInstruction(const Instruction &I, unsigned InstID,
 910                              ValueEnumerator &VE, BitstreamWriter &Stream,
 911                              SmallVector<unsigned, 64> &Vals) {
 912   unsigned Code = 0;
 913   unsigned AbbrevToUse = 0;
 914   VE.setInstructionID(&I);
 915   switch (I.getOpcode()) {
 916   default:
 917     if (Instruction::isCast(I.getOpcode())) {
 918       Code = bitc::FUNC_CODE_INST_CAST;
 919       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 920         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 921       Vals.push_back(VE.getTypeID(I.getType()));
 922       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 923     } else {
 924       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 925       Code = bitc::FUNC_CODE_INST_BINOP;
 926       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 927         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 928       Vals.push_back(VE.getValueID(I.getOperand(1)));
 929       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 930       uint64_t Flags = GetOptimizationFlags(&I);
 931       if (Flags != 0) {
 932         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 933           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 934         Vals.push_back(Flags);
 935       }
 936     }
 937     break;
 938
 939   case Instruction::GetElementPtr:
 940     Code = bitc::FUNC_CODE_INST_GEP;
 941     if (cast<GEPOperator>(&I)->isInBounds())
 942       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 943     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 944       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 945     break;
 946   case Instruction::ExtractValue: {
 947     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 948     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 949     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 950     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 951       Vals.push_back(*i);
 952     break;
 953   }
 954   case Instruction::InsertValue: {
 955     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 956     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 957     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 958     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 959     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 960       Vals.push_back(*i);
 961     break;
 962   }
 963   case Instruction::Select:
 964     Code = bitc::FUNC_CODE_INST_VSELECT;
 965     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 966     Vals.push_back(VE.getValueID(I.getOperand(2)));
 967     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 968     break;
 969   case Instruction::ExtractElement:
 970     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 971     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 972     Vals.push_back(VE.getValueID(I.getOperand(1)));
 973     break;
 974   case Instruction::InsertElement:
 975     Code = bitc::FUNC_CODE_INST_INSERTELT;
 976     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 977     Vals.push_back(VE.getValueID(I.getOperand(1)));
 978     Vals.push_back(VE.getValueID(I.getOperand(2)));
 979     break;
 980   case Instruction::ShuffleVector:
 981     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 982     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 983     Vals.push_back(VE.getValueID(I.getOperand(1)));
 984     Vals.push_back(VE.getValueID(I.getOperand(2)));
 985     break;
 986   case Instruction::ICmp:
 987   case Instruction::FCmp:
 988     // compare returning Int1Ty or vector of Int1Ty
 989     Code = bitc::FUNC_CODE_INST_CMP2;
 990     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 991     Vals.push_back(VE.getValueID(I.getOperand(1)));
 992     Vals.push_back(cast<CmpInst>(I).getPredicate());
 993     break;
 994
 995   case Instruction::Ret:
 996     {
 997       Code = bitc::FUNC_CODE_INST_RET;
 998       unsigned NumOperands = I.getNumOperands();
 999       if (NumOperands == 0)
1000         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1001       else if (NumOperands == 1) {
1002         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1003           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1004       } else {
1005         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1006           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1007       }
1008     }
1009     break;
1010   case Instruction::Br:
1011     {
1012       Code = bitc::FUNC_CODE_INST_BR;
1013       BranchInst &II = cast<BranchInst>(I);
1014       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1015       if (II.isConditional()) {
1016         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1017         Vals.push_back(VE.getValueID(II.getCondition()));
1018       }
1019     }
1020     break;
1021   case Instruction::Switch:
1022     Code = bitc::FUNC_CODE_INST_SWITCH;
1023     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1024     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1025       Vals.push_back(VE.getValueID(I.getOperand(i)));
1026     break;
1027   case Instruction::IndirectBr:
1028     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1029     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1030     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1031       Vals.push_back(VE.getValueID(I.getOperand(i)));
1032     break;
1033
1034   case Instruction::Invoke: {
1035     const InvokeInst *II = cast<InvokeInst>(&I);
1036     const Value *Callee(II->getCalledValue());
1037     const PointerType *PTy = cast<PointerType>(Callee->getType());
1038     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1039     Code = bitc::FUNC_CODE_INST_INVOKE;
1040
1041     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1042     Vals.push_back(II->getCallingConv());
1043     Vals.push_back(VE.getValueID(II->getNormalDest()));
1044     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1045     PushValueAndType(Callee, InstID, Vals, VE);
1046
1047     // Emit value #'s for the fixed parameters.
1048     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1049       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1050
1051     // Emit type/value pairs for varargs params.
1052     if (FTy->isVarArg()) {
1053       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1054            i != e; ++i)
1055         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1056     }
1057     break;
1058   }
1059   case Instruction::Unwind:
1060     Code = bitc::FUNC_CODE_INST_UNWIND;
1061     break;
1062   case Instruction::Unreachable:
1063     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1064     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1065     break;
1066
1067   case Instruction::PHI:
1068     Code = bitc::FUNC_CODE_INST_PHI;
1069     Vals.push_back(VE.getTypeID(I.getType()));
1070     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1071       Vals.push_back(VE.getValueID(I.getOperand(i)));
1072     break;
1073
1074   case Instruction::Alloca:
1075     Code = bitc::FUNC_CODE_INST_ALLOCA;
1076     Vals.push_back(VE.getTypeID(I.getType()));
1077     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1078     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1079     break;
1080
1081   case Instruction::Load:
1082     Code = bitc::FUNC_CODE_INST_LOAD;
1083     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1084       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1085
1086     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1087     Vals.push_back(cast<LoadInst>(I).isVolatile());
1088     break;
1089   case Instruction::Store:
1090     Code = bitc::FUNC_CODE_INST_STORE2;
1091     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1092     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1093     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1094     Vals.push_back(cast<StoreInst>(I).isVolatile());
1095     break;
1096   case Instruction::Call: {
1097     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1098     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1099
1100     Code = bitc::FUNC_CODE_INST_CALL;
1101
1102     const CallInst *CI = cast<CallInst>(&I);
1103     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1104     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1105     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1106
1107     // Emit value #'s for the fixed parameters.
1108     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1109       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1110
1111     // Emit type/value pairs for varargs params.
1112     if (FTy->isVarArg()) {
1113       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1114       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1115            i != e; ++i)
1116         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1117     }
1118     break;
1119   }
1120   case Instruction::VAArg:
1121     Code = bitc::FUNC_CODE_INST_VAARG;
1122     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1123     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1124     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1125     break;
1126   }
1127
1128   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1129   Vals.clear();
1130 }
1131
1132 // Emit names for globals/functions etc.
1133 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1134                                   const ValueEnumerator &VE,
1135                                   BitstreamWriter &Stream) {
1136   if (VST.empty()) return;
1137   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1138
1139   // FIXME: Set up the abbrev, we know how many values there are!
1140   // FIXME: We know if the type names can use 7-bit ascii.
1141   SmallVector<unsigned, 64> NameVals;
1142
1143   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1144        SI != SE; ++SI) {
1145
1146     const ValueName &Name = *SI;
1147
1148     // Figure out the encoding to use for the name.
1149     bool is7Bit = true;
1150     bool isChar6 = true;
1151     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1152          C != E; ++C) {
1153       if (isChar6)
1154         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1155       if ((unsigned char)*C & 128) {
1156         is7Bit = false;
1157         break;  // don't bother scanning the rest.
1158       }
1159     }
1160
1161     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1162
1163     // VST_ENTRY:   [valueid, namechar x N]
1164     // VST_BBENTRY: [bbid, namechar x N]
1165     unsigned Code;
1166     if (isa<BasicBlock>(SI->getValue())) {
1167       Code = bitc::VST_CODE_BBENTRY;
1168       if (isChar6)
1169         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1170     } else {
1171       Code = bitc::VST_CODE_ENTRY;
1172       if (isChar6)
1173         AbbrevToUse = VST_ENTRY_6_ABBREV;
1174       else if (is7Bit)
1175         AbbrevToUse = VST_ENTRY_7_ABBREV;
1176     }
1177
1178     NameVals.push_back(VE.getValueID(SI->getValue()));
1179     for (const char *P = Name.getKeyData(),
1180          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1181       NameVals.push_back((unsigned char)*P);
1182
1183     // Emit the finished record.
1184     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1185     NameVals.clear();
1186   }
1187   Stream.ExitBlock();
1188 }
1189
1190 /// WriteFunction - Emit a function body to the module stream.
1191 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1192                           BitstreamWriter &Stream) {
1193   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1194   VE.incorporateFunction(F);
1195
1196   SmallVector<unsigned, 64> Vals;
1197
1198   // Emit the number of basic blocks, so the reader can create them ahead of
1199   // time.
1200   Vals.push_back(VE.getBasicBlocks().size());
1201   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1202   Vals.clear();
1203
1204   // If there are function-local constants, emit them now.
1205   unsigned CstStart, CstEnd;
1206   VE.getFunctionConstantRange(CstStart, CstEnd);
1207   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1208
1209   // Keep a running idea of what the instruction ID is.
1210   unsigned InstID = CstEnd;
1211
1212   // Finally, emit all the instructions, in order.
1213   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1214     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1215          I != E; ++I) {
1216       WriteInstruction(*I, InstID, VE, Stream, Vals);
1217       if (I->getType() != Type::getVoidTy(F.getContext()))
1218         ++InstID;
1219     }
1220
1221   // Emit names for all the instructions etc.
1222   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1223
1224   WriteMetadataAttachment(F, VE, Stream);
1225   VE.purgeFunction();
1226   Stream.ExitBlock();
1227 }
1228
1229 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1230 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1231                                  const ValueEnumerator &VE,
1232                                  BitstreamWriter &Stream) {
1233   if (TST.empty()) return;
1234
1235   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1236
1237   // 7-bit fixed width VST_CODE_ENTRY strings.
1238   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1239   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1240   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1241                             Log2_32_Ceil(VE.getTypes().size()+1)));
1242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1243   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1244   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1245
1246   SmallVector<unsigned, 64> NameVals;
1247
1248   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1249        TI != TE; ++TI) {
1250     // TST_ENTRY: [typeid, namechar x N]
1251     NameVals.push_back(VE.getTypeID(TI->second));
1252
1253     const std::string &Str = TI->first;
1254     bool is7Bit = true;
1255     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1256       NameVals.push_back((unsigned char)Str[i]);
1257       if (Str[i] & 128)
1258         is7Bit = false;
1259     }
1260
1261     // Emit the finished record.
1262     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1263     NameVals.clear();
1264   }
1265
1266   Stream.ExitBlock();
1267 }
1268
1269 // Emit blockinfo, which defines the standard abbreviations etc.
1270 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1271   // We only want to emit block info records for blocks that have multiple
1272   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1273   // blocks can defined their abbrevs inline.
1274   Stream.EnterBlockInfoBlock(2);
1275
1276   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1277     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1282     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1283                                    Abbv) != VST_ENTRY_8_ABBREV)
1284       llvm_unreachable("Unexpected abbrev ordering!");
1285   }
1286
1287   { // 7-bit fixed width VST_ENTRY strings.
1288     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1289     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1293     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1294                                    Abbv) != VST_ENTRY_7_ABBREV)
1295       llvm_unreachable("Unexpected abbrev ordering!");
1296   }
1297   { // 6-bit char6 VST_ENTRY strings.
1298     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1299     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1303     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1304                                    Abbv) != VST_ENTRY_6_ABBREV)
1305       llvm_unreachable("Unexpected abbrev ordering!");
1306   }
1307   { // 6-bit char6 VST_BBENTRY strings.
1308     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1309     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1313     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1314                                    Abbv) != VST_BBENTRY_6_ABBREV)
1315       llvm_unreachable("Unexpected abbrev ordering!");
1316   }
1317
1318
1319
1320   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1321     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1322     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1324                               Log2_32_Ceil(VE.getTypes().size()+1)));
1325     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1326                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1327       llvm_unreachable("Unexpected abbrev ordering!");
1328   }
1329
1330   { // INTEGER abbrev for CONSTANTS_BLOCK.
1331     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1332     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1334     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1335                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1336       llvm_unreachable("Unexpected abbrev ordering!");
1337   }
1338
1339   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1340     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1341     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1344                               Log2_32_Ceil(VE.getTypes().size()+1)));
1345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1346
1347     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1348                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1349       llvm_unreachable("Unexpected abbrev ordering!");
1350   }
1351   { // NULL abbrev for CONSTANTS_BLOCK.
1352     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1353     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1354     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1355                                    Abbv) != CONSTANTS_NULL_Abbrev)
1356       llvm_unreachable("Unexpected abbrev ordering!");
1357   }
1358
1359   // FIXME: This should only use space for first class types!
1360
1361   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1362     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1363     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1367     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1368                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1369       llvm_unreachable("Unexpected abbrev ordering!");
1370   }
1371   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1372     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1373     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1377     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1378                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1379       llvm_unreachable("Unexpected abbrev ordering!");
1380   }
1381   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1382     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1383     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1387     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1388     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1389                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1390       llvm_unreachable("Unexpected abbrev ordering!");
1391   }
1392   { // INST_CAST abbrev for FUNCTION_BLOCK.
1393     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1394     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1397                               Log2_32_Ceil(VE.getTypes().size()+1)));
1398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1399     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1400                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1401       llvm_unreachable("Unexpected abbrev ordering!");
1402   }
1403
1404   { // INST_RET abbrev for FUNCTION_BLOCK.
1405     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1406     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1407     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1408                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1409       llvm_unreachable("Unexpected abbrev ordering!");
1410   }
1411   { // INST_RET abbrev for FUNCTION_BLOCK.
1412     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1413     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1415     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1416                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1417       llvm_unreachable("Unexpected abbrev ordering!");
1418   }
1419   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1420     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1421     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1422     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1423                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1424       llvm_unreachable("Unexpected abbrev ordering!");
1425   }
1426
1427   Stream.ExitBlock();
1428 }
1429
1430
1431 /// WriteModule - Emit the specified module to the bitstream.
1432 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1433   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1434
1435   // Emit the version number if it is non-zero.
1436   if (CurVersion) {
1437     SmallVector<unsigned, 1> Vals;
1438     Vals.push_back(CurVersion);
1439     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1440   }
1441
1442   // Analyze the module, enumerating globals, functions, etc.
1443   ValueEnumerator VE(M);
1444
1445   // Emit blockinfo, which defines the standard abbreviations etc.
1446   WriteBlockInfo(VE, Stream);
1447
1448   // Emit information about parameter attributes.
1449   WriteAttributeTable(VE, Stream);
1450
1451   // Emit information describing all of the types in the module.
1452   WriteTypeTable(VE, Stream);
1453
1454   // Emit top-level description of module, including target triple, inline asm,
1455   // descriptors for global variables, and function prototype info.
1456   WriteModuleInfo(M, VE, Stream);
1457
1458   // Emit constants.
1459   WriteModuleConstants(VE, Stream);
1460
1461   // Emit metadata.
1462   WriteModuleMetadata(VE, Stream);
1463
1464   // Emit function bodies.
1465   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1466     if (!I->isDeclaration())
1467       WriteFunction(*I, VE, Stream);
1468
1469   // Emit metadata.
1470   WriteModuleMetadataStore(M, VE, Stream);
1471
1472   // Emit the type symbol table information.
1473   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1474
1475   // Emit names for globals/functions etc.
1476   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1477
1478   Stream.ExitBlock();
1479 }
1480
1481 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1482 /// header and trailer to make it compatible with the system archiver.  To do
1483 /// this we emit the following header, and then emit a trailer that pads the
1484 /// file out to be a multiple of 16 bytes.
1485 ///
1486 /// struct bc_header {
1487 ///   uint32_t Magic;         // 0x0B17C0DE
1488 ///   uint32_t Version;       // Version, currently always 0.
1489 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1490 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1491 ///   uint32_t CPUType;       // CPU specifier.
1492 ///   ... potentially more later ...
1493 /// };
1494 enum {
1495   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1496   DarwinBCHeaderSize = 5*4
1497 };
1498
1499 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1500                                const std::string &TT) {
1501   unsigned CPUType = ~0U;
1502
1503   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1504   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1505   // specific constants here because they are implicitly part of the Darwin ABI.
1506   enum {
1507     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1508     DARWIN_CPU_TYPE_X86        = 7,
1509     DARWIN_CPU_TYPE_POWERPC    = 18
1510   };
1511
1512   if (TT.find("x86_64-") == 0)
1513     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1514   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1515            TT[4] == '-' && TT[1] - '3' < 6)
1516     CPUType = DARWIN_CPU_TYPE_X86;
1517   else if (TT.find("powerpc-") == 0)
1518     CPUType = DARWIN_CPU_TYPE_POWERPC;
1519   else if (TT.find("powerpc64-") == 0)
1520     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1521
1522   // Traditional Bitcode starts after header.
1523   unsigned BCOffset = DarwinBCHeaderSize;
1524
1525   Stream.Emit(0x0B17C0DE, 32);
1526   Stream.Emit(0         , 32);  // Version.
1527   Stream.Emit(BCOffset  , 32);
1528   Stream.Emit(0         , 32);  // Filled in later.
1529   Stream.Emit(CPUType   , 32);
1530 }
1531
1532 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1533 /// finalize the header.
1534 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1535   // Update the size field in the header.
1536   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1537
1538   // If the file is not a multiple of 16 bytes, insert dummy padding.
1539   while (BufferSize & 15) {
1540     Stream.Emit(0, 8);
1541     ++BufferSize;
1542   }
1543 }
1544
1545
1546 /// WriteBitcodeToFile - Write the specified module to the specified output
1547 /// stream.
1548 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1549   std::vector<unsigned char> Buffer;
1550   BitstreamWriter Stream(Buffer);
1551
1552   Buffer.reserve(256*1024);
1553
1554   WriteBitcodeToStream( M, Stream );
1555
1556   // If writing to stdout, set binary mode.
1557   if (&llvm::outs() == &Out)
1558     sys::Program::ChangeStdoutToBinary();
1559
1560   // Write the generated bitstream to "Out".
1561   Out.write((char*)&Buffer.front(), Buffer.size());
1562
1563   // Make sure it hits disk now.
1564   Out.flush();
1565 }
1566
1567 /// WriteBitcodeToStream - Write the specified module to the specified output
1568 /// stream.
1569 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1570   // If this is darwin, emit a file header and trailer if needed.
1571   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1572   if (isDarwin)
1573     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1574
1575   // Emit the file header.
1576   Stream.Emit((unsigned)'B', 8);
1577   Stream.Emit((unsigned)'C', 8);
1578   Stream.Emit(0x0, 4);
1579   Stream.Emit(0xC, 4);
1580   Stream.Emit(0xE, 4);
1581   Stream.Emit(0xD, 4);
1582
1583   // Emit the module.
1584   WriteModule(M, Stream);
1585
1586   if (isDarwin)
1587     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1588 }