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_UNION.
 185   Abbv = new BitCodeAbbrev();
 186   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_UNION));
 187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 189                             Log2_32_Ceil(VE.getTypes().size()+1)));
 190   unsigned UnionAbbrev = Stream.EmitAbbrev(Abbv);
 191
 192   // Abbrev for TYPE_CODE_ARRAY.
 193   Abbv = new BitCodeAbbrev();
 194   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 197                             Log2_32_Ceil(VE.getTypes().size()+1)));
 198   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 199
 200   // Emit an entry count so the reader can reserve space.
 201   TypeVals.push_back(TypeList.size());
 202   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 203   TypeVals.clear();
 204
 205   // Loop over all of the types, emitting each in turn.
 206   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 207     const Type *T = TypeList[i].first;
 208     int AbbrevToUse = 0;
 209     unsigned Code = 0;
 210
 211     switch (T->getTypeID()) {
 212     default: llvm_unreachable("Unknown type!");
 213     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 214     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 215     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 216     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 217     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 218     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 219     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 220     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 221     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 222     case Type::IntegerTyID:
 223       // INTEGER: [width]
 224       Code = bitc::TYPE_CODE_INTEGER;
 225       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 226       break;
 227     case Type::PointerTyID: {
 228       const PointerType *PTy = cast<PointerType>(T);
 229       // POINTER: [pointee type, address space]
 230       Code = bitc::TYPE_CODE_POINTER;
 231       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 232       unsigned AddressSpace = PTy->getAddressSpace();
 233       TypeVals.push_back(AddressSpace);
 234       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 235       break;
 236     }
 237     case Type::FunctionTyID: {
 238       const FunctionType *FT = cast<FunctionType>(T);
 239       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 240       Code = bitc::TYPE_CODE_FUNCTION;
 241       TypeVals.push_back(FT->isVarArg());
 242       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 243       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 244       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 245         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 246       AbbrevToUse = FunctionAbbrev;
 247       break;
 248     }
 249     case Type::StructTyID: {
 250       const StructType *ST = cast<StructType>(T);
 251       // STRUCT: [ispacked, eltty x N]
 252       Code = bitc::TYPE_CODE_STRUCT;
 253       TypeVals.push_back(ST->isPacked());
 254       // Output all of the element types.
 255       for (StructType::element_iterator I = ST->element_begin(),
 256            E = ST->element_end(); I != E; ++I)
 257         TypeVals.push_back(VE.getTypeID(*I));
 258       AbbrevToUse = StructAbbrev;
 259       break;
 260     }
 261     case Type::UnionTyID: {
 262       const UnionType *UT = cast<UnionType>(T);
 263       // UNION: [eltty x N]
 264       Code = bitc::TYPE_CODE_UNION;
 265       // Output all of the element types.
 266       for (UnionType::element_iterator I = UT->element_begin(),
 267            E = UT->element_end(); I != E; ++I)
 268         TypeVals.push_back(VE.getTypeID(*I));
 269       AbbrevToUse = UnionAbbrev;
 270       break;
 271     }
 272     case Type::ArrayTyID: {
 273       const ArrayType *AT = cast<ArrayType>(T);
 274       // ARRAY: [numelts, eltty]
 275       Code = bitc::TYPE_CODE_ARRAY;
 276       TypeVals.push_back(AT->getNumElements());
 277       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 278       AbbrevToUse = ArrayAbbrev;
 279       break;
 280     }
 281     case Type::VectorTyID: {
 282       const VectorType *VT = cast<VectorType>(T);
 283       // VECTOR [numelts, eltty]
 284       Code = bitc::TYPE_CODE_VECTOR;
 285       TypeVals.push_back(VT->getNumElements());
 286       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 287       break;
 288     }
 289     }
 290
 291     // Emit the finished record.
 292     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 293     TypeVals.clear();
 294   }
 295
 296   Stream.ExitBlock();
 297 }
 298
 299 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 300   switch (GV->getLinkage()) {
 301   default: llvm_unreachable("Invalid linkage!");
 302   case GlobalValue::ExternalLinkage:            return 0;
 303   case GlobalValue::WeakAnyLinkage:             return 1;
 304   case GlobalValue::AppendingLinkage:           return 2;
 305   case GlobalValue::InternalLinkage:            return 3;
 306   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 307   case GlobalValue::DLLImportLinkage:           return 5;
 308   case GlobalValue::DLLExportLinkage:           return 6;
 309   case GlobalValue::ExternalWeakLinkage:        return 7;
 310   case GlobalValue::CommonLinkage:              return 8;
 311   case GlobalValue::PrivateLinkage:             return 9;
 312   case GlobalValue::WeakODRLinkage:             return 10;
 313   case GlobalValue::LinkOnceODRLinkage:         return 11;
 314   case GlobalValue::AvailableExternallyLinkage: return 12;
 315   case GlobalValue::LinkerPrivateLinkage:       return 13;
 316   }
 317 }
 318
 319 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 320   switch (GV->getVisibility()) {
 321   default: llvm_unreachable("Invalid visibility!");
 322   case GlobalValue::DefaultVisibility:   return 0;
 323   case GlobalValue::HiddenVisibility:    return 1;
 324   case GlobalValue::ProtectedVisibility: return 2;
 325   }
 326 }
 327
 328 // Emit top-level description of module, including target triple, inline asm,
 329 // descriptors for global variables, and function prototype info.
 330 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 331                             BitstreamWriter &Stream) {
 332   // Emit the list of dependent libraries for the Module.
 333   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 334     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 335
 336   // Emit various pieces of data attached to a module.
 337   if (!M->getTargetTriple().empty())
 338     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 339                       0/*TODO*/, Stream);
 340   if (!M->getDataLayout().empty())
 341     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 342                       0/*TODO*/, Stream);
 343   if (!M->getModuleInlineAsm().empty())
 344     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 345                       0/*TODO*/, Stream);
 346
 347   // Emit information about sections and GC, computing how many there are. Also
 348   // compute the maximum alignment value.
 349   std::map<std::string, unsigned> SectionMap;
 350   std::map<std::string, unsigned> GCMap;
 351   unsigned MaxAlignment = 0;
 352   unsigned MaxGlobalType = 0;
 353   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 354        GV != E; ++GV) {
 355     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 356     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 357
 358     if (!GV->hasSection()) continue;
 359     // Give section names unique ID's.
 360     unsigned &Entry = SectionMap[GV->getSection()];
 361     if (Entry != 0) continue;
 362     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 363                       0/*TODO*/, Stream);
 364     Entry = SectionMap.size();
 365   }
 366   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 367     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 368     if (F->hasSection()) {
 369       // Give section names unique ID's.
 370       unsigned &Entry = SectionMap[F->getSection()];
 371       if (!Entry) {
 372         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 373                           0/*TODO*/, Stream);
 374         Entry = SectionMap.size();
 375       }
 376     }
 377     if (F->hasGC()) {
 378       // Same for GC names.
 379       unsigned &Entry = GCMap[F->getGC()];
 380       if (!Entry) {
 381         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 382                           0/*TODO*/, Stream);
 383         Entry = GCMap.size();
 384       }
 385     }
 386   }
 387
 388   // Emit abbrev for globals, now that we know # sections and max alignment.
 389   unsigned SimpleGVarAbbrev = 0;
 390   if (!M->global_empty()) {
 391     // Add an abbrev for common globals with no visibility or thread localness.
 392     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 393     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 395                               Log2_32_Ceil(MaxGlobalType+1)));
 396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 399     if (MaxAlignment == 0)                                      // Alignment.
 400       Abbv->Add(BitCodeAbbrevOp(0));
 401     else {
 402       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 403       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 404                                Log2_32_Ceil(MaxEncAlignment+1)));
 405     }
 406     if (SectionMap.empty())                                    // Section.
 407       Abbv->Add(BitCodeAbbrevOp(0));
 408     else
 409       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 410                                Log2_32_Ceil(SectionMap.size()+1)));
 411     // Don't bother emitting vis + thread local.
 412     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 413   }
 414
 415   // Emit the global variable information.
 416   SmallVector<unsigned, 64> Vals;
 417   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 418        GV != E; ++GV) {
 419     unsigned AbbrevToUse = 0;
 420
 421     // GLOBALVAR: [type, isconst, initid,
 422     //             linkage, alignment, section, visibility, threadlocal]
 423     Vals.push_back(VE.getTypeID(GV->getType()));
 424     Vals.push_back(GV->isConstant());
 425     Vals.push_back(GV->isDeclaration() ? 0 :
 426                    (VE.getValueID(GV->getInitializer()) + 1));
 427     Vals.push_back(getEncodedLinkage(GV));
 428     Vals.push_back(Log2_32(GV->getAlignment())+1);
 429     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 430     if (GV->isThreadLocal() ||
 431         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 432       Vals.push_back(getEncodedVisibility(GV));
 433       Vals.push_back(GV->isThreadLocal());
 434     } else {
 435       AbbrevToUse = SimpleGVarAbbrev;
 436     }
 437
 438     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 439     Vals.clear();
 440   }
 441
 442   // Emit the function proto information.
 443   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 444     // FUNCTION:  [type, callingconv, isproto, paramattr,
 445     //             linkage, alignment, section, visibility, gc]
 446     Vals.push_back(VE.getTypeID(F->getType()));
 447     Vals.push_back(F->getCallingConv());
 448     Vals.push_back(F->isDeclaration());
 449     Vals.push_back(getEncodedLinkage(F));
 450     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 451     Vals.push_back(Log2_32(F->getAlignment())+1);
 452     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 453     Vals.push_back(getEncodedVisibility(F));
 454     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 455
 456     unsigned AbbrevToUse = 0;
 457     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 458     Vals.clear();
 459   }
 460
 461
 462   // Emit the alias information.
 463   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 464        AI != E; ++AI) {
 465     Vals.push_back(VE.getTypeID(AI->getType()));
 466     Vals.push_back(VE.getValueID(AI->getAliasee()));
 467     Vals.push_back(getEncodedLinkage(AI));
 468     Vals.push_back(getEncodedVisibility(AI));
 469     unsigned AbbrevToUse = 0;
 470     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 471     Vals.clear();
 472   }
 473 }
 474
 475 static uint64_t GetOptimizationFlags(const Value *V) {
 476   uint64_t Flags = 0;
 477
 478   if (const OverflowingBinaryOperator *OBO =
 479         dyn_cast<OverflowingBinaryOperator>(V)) {
 480     if (OBO->hasNoSignedWrap())
 481       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 482     if (OBO->hasNoUnsignedWrap())
 483       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 484   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 485     if (Div->isExact())
 486       Flags |= 1 << bitc::SDIV_EXACT;
 487   }
 488
 489   return Flags;
 490 }
 491
 492 static void WriteMDNode(const MDNode *N,
 493                         const ValueEnumerator &VE,
 494                         BitstreamWriter &Stream,
 495                         SmallVector<uint64_t, 64> &Record) {
 496   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 497     if (N->getOperand(i)) {
 498       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 499       Record.push_back(VE.getValueID(N->getOperand(i)));
 500     } else {
 501       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 502       Record.push_back(0);
 503     }
 504   }
 505   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 506                                            bitc::METADATA_NODE;
 507   Stream.EmitRecord(MDCode, Record, 0);
 508   Record.clear();
 509 }
 510
 511 static void WriteModuleMetadata(const ValueEnumerator &VE,
 512                                 BitstreamWriter &Stream) {
 513   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 514   bool StartedMetadataBlock = false;
 515   unsigned MDSAbbrev = 0;
 516   SmallVector<uint64_t, 64> Record;
 517   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 518
 519     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 520       if (!N->isFunctionLocal() || !N->getFunction()) {
 521         if (!StartedMetadataBlock) {
 522           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 523           StartedMetadataBlock = true;
 524         }
 525         WriteMDNode(N, VE, Stream, Record);
 526       }
 527     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 528       if (!StartedMetadataBlock)  {
 529         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 530
 531         // Abbrev for METADATA_STRING.
 532         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 533         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 534         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 535         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 536         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 537         StartedMetadataBlock = true;
 538       }
 539
 540       // Code: [strchar x N]
 541       Record.append(MDS->begin(), MDS->end());
 542
 543       // Emit the finished record.
 544       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 545       Record.clear();
 546     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 547       if (!StartedMetadataBlock)  {
 548         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 549         StartedMetadataBlock = true;
 550       }
 551
 552       // Write name.
 553       StringRef Str = NMD->getName();
 554       for (unsigned i = 0, e = Str.size(); i != e; ++i)
 555         Record.push_back(Str[i]);
 556       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 557       Record.clear();
 558
 559       // Write named metadata operands.
 560       for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
 561         if (NMD->getOperand(i))
 562           Record.push_back(VE.getValueID(NMD->getOperand(i)));
 563         else
 564           Record.push_back(~0U);
 565       }
 566       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 567       Record.clear();
 568     }
 569   }
 570
 571   if (StartedMetadataBlock)
 572     Stream.ExitBlock();
 573 }
 574
 575 static void WriteFunctionLocalMetadata(const Function &F,
 576                                        const ValueEnumerator &VE,
 577                                        BitstreamWriter &Stream) {
 578   bool StartedMetadataBlock = false;
 579   SmallVector<uint64_t, 64> Record;
 580   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 581
 582   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 583     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first))
 584       if (N->isFunctionLocal() && N->getFunction() == &F) {
 585         if (!StartedMetadataBlock) {
 586           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 587           StartedMetadataBlock = true;
 588         }
 589         WriteMDNode(N, VE, Stream, Record);
 590       }
 591
 592   if (StartedMetadataBlock)
 593     Stream.ExitBlock();
 594 }
 595
 596 static void WriteMetadataAttachment(const Function &F,
 597                                     const ValueEnumerator &VE,
 598                                     BitstreamWriter &Stream) {
 599   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 600
 601   SmallVector<uint64_t, 64> Record;
 602
 603   // Write metadata attachments
 604   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 605   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 606
 607   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 608     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 609          I != E; ++I) {
 610       MDs.clear();
 611       I->getAllMetadataOtherThanDebugLoc(MDs);
 612
 613       // If no metadata, ignore instruction.
 614       if (MDs.empty()) continue;
 615
 616       Record.push_back(VE.getInstructionID(I));
 617
 618       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 619         Record.push_back(MDs[i].first);
 620         Record.push_back(VE.getValueID(MDs[i].second));
 621       }
 622       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 623       Record.clear();
 624     }
 625
 626   Stream.ExitBlock();
 627 }
 628
 629 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 630   SmallVector<uint64_t, 64> Record;
 631
 632   // Write metadata kinds
 633   // METADATA_KIND - [n x [id, name]]
 634   SmallVector<StringRef, 4> Names;
 635   M->getMDKindNames(Names);
 636
 637   assert(Names[0] == "" && "MDKind #0 is invalid");
 638   if (Names.size() == 1) return;
 639
 640   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 641
 642   for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
 643     Record.push_back(MDKindID);
 644     StringRef KName = Names[MDKindID];
 645     Record.append(KName.begin(), KName.end());
 646
 647     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 648     Record.clear();
 649   }
 650
 651   Stream.ExitBlock();
 652 }
 653
 654 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 655                            const ValueEnumerator &VE,
 656                            BitstreamWriter &Stream, bool isGlobal) {
 657   if (FirstVal == LastVal) return;
 658
 659   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 660
 661   unsigned AggregateAbbrev = 0;
 662   unsigned String8Abbrev = 0;
 663   unsigned CString7Abbrev = 0;
 664   unsigned CString6Abbrev = 0;
 665   // If this is a constant pool for the module, emit module-specific abbrevs.
 666   if (isGlobal) {
 667     // Abbrev for CST_CODE_AGGREGATE.
 668     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 669     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 672     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 673
 674     // Abbrev for CST_CODE_STRING.
 675     Abbv = new BitCodeAbbrev();
 676     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 679     String8Abbrev = Stream.EmitAbbrev(Abbv);
 680     // Abbrev for CST_CODE_CSTRING.
 681     Abbv = new BitCodeAbbrev();
 682     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 683     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 684     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 685     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 686     // Abbrev for CST_CODE_CSTRING.
 687     Abbv = new BitCodeAbbrev();
 688     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 689     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 690     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 691     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 692   }
 693
 694   SmallVector<uint64_t, 64> Record;
 695
 696   const ValueEnumerator::ValueList &Vals = VE.getValues();
 697   const Type *LastTy = 0;
 698   for (unsigned i = FirstVal; i != LastVal; ++i) {
 699     const Value *V = Vals[i].first;
 700     // If we need to switch types, do so now.
 701     if (V->getType() != LastTy) {
 702       LastTy = V->getType();
 703       Record.push_back(VE.getTypeID(LastTy));
 704       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 705                         CONSTANTS_SETTYPE_ABBREV);
 706       Record.clear();
 707     }
 708
 709     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 710       Record.push_back(unsigned(IA->hasSideEffects()) |
 711                        unsigned(IA->isAlignStack()) << 1);
 712
 713       // Add the asm string.
 714       const std::string &AsmStr = IA->getAsmString();
 715       Record.push_back(AsmStr.size());
 716       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 717         Record.push_back(AsmStr[i]);
 718
 719       // Add the constraint string.
 720       const std::string &ConstraintStr = IA->getConstraintString();
 721       Record.push_back(ConstraintStr.size());
 722       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 723         Record.push_back(ConstraintStr[i]);
 724       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 725       Record.clear();
 726       continue;
 727     }
 728     const Constant *C = cast<Constant>(V);
 729     unsigned Code = -1U;
 730     unsigned AbbrevToUse = 0;
 731     if (C->isNullValue()) {
 732       Code = bitc::CST_CODE_NULL;
 733     } else if (isa<UndefValue>(C)) {
 734       Code = bitc::CST_CODE_UNDEF;
 735     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 736       if (IV->getBitWidth() <= 64) {
 737         int64_t V = IV->getSExtValue();
 738         if (V >= 0)
 739           Record.push_back(V << 1);
 740         else
 741           Record.push_back((-V << 1) | 1);
 742         Code = bitc::CST_CODE_INTEGER;
 743         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 744       } else {                             // Wide integers, > 64 bits in size.
 745         // We have an arbitrary precision integer value to write whose
 746         // bit width is > 64. However, in canonical unsigned integer
 747         // format it is likely that the high bits are going to be zero.
 748         // So, we only write the number of active words.
 749         unsigned NWords = IV->getValue().getActiveWords();
 750         const uint64_t *RawWords = IV->getValue().getRawData();
 751         for (unsigned i = 0; i != NWords; ++i) {
 752           int64_t V = RawWords[i];
 753           if (V >= 0)
 754             Record.push_back(V << 1);
 755           else
 756             Record.push_back((-V << 1) | 1);
 757         }
 758         Code = bitc::CST_CODE_WIDE_INTEGER;
 759       }
 760     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 761       Code = bitc::CST_CODE_FLOAT;
 762       const Type *Ty = CFP->getType();
 763       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 764         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 765       } else if (Ty->isX86_FP80Ty()) {
 766         // api needed to prevent premature destruction
 767         // bits are not in the same order as a normal i80 APInt, compensate.
 768         APInt api = CFP->getValueAPF().bitcastToAPInt();
 769         const uint64_t *p = api.getRawData();
 770         Record.push_back((p[1] << 48) | (p[0] >> 16));
 771         Record.push_back(p[0] & 0xffffLL);
 772       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 773         APInt api = CFP->getValueAPF().bitcastToAPInt();
 774         const uint64_t *p = api.getRawData();
 775         Record.push_back(p[0]);
 776         Record.push_back(p[1]);
 777       } else {
 778         assert (0 && "Unknown FP type!");
 779       }
 780     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 781       const ConstantArray *CA = cast<ConstantArray>(C);
 782       // Emit constant strings specially.
 783       unsigned NumOps = CA->getNumOperands();
 784       // If this is a null-terminated string, use the denser CSTRING encoding.
 785       if (CA->getOperand(NumOps-1)->isNullValue()) {
 786         Code = bitc::CST_CODE_CSTRING;
 787         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 788       } else {
 789         Code = bitc::CST_CODE_STRING;
 790         AbbrevToUse = String8Abbrev;
 791       }
 792       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 793       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 794       for (unsigned i = 0; i != NumOps; ++i) {
 795         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 796         Record.push_back(V);
 797         isCStr7 &= (V & 128) == 0;
 798         if (isCStrChar6)
 799           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 800       }
 801
 802       if (isCStrChar6)
 803         AbbrevToUse = CString6Abbrev;
 804       else if (isCStr7)
 805         AbbrevToUse = CString7Abbrev;
 806     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 807                isa<ConstantVector>(V)) {
 808       Code = bitc::CST_CODE_AGGREGATE;
 809       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 810         Record.push_back(VE.getValueID(C->getOperand(i)));
 811       AbbrevToUse = AggregateAbbrev;
 812     } else if (isa<ConstantUnion>(C)) {
 813       Code = bitc::CST_CODE_AGGREGATE;
 814
 815       // Unions only have one entry but we must send type along with it.
 816       const Type *EntryKind = C->getOperand(0)->getType();
 817
 818       const UnionType *UnTy = cast<UnionType>(C->getType());
 819       int UnionIndex = UnTy->getElementTypeIndex(EntryKind);
 820       assert(UnionIndex != -1 && "Constant union contains invalid entry");
 821
 822       Record.push_back(UnionIndex);
 823       Record.push_back(VE.getValueID(C->getOperand(0)));
 824
 825       AbbrevToUse = AggregateAbbrev;
 826     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 827       switch (CE->getOpcode()) {
 828       default:
 829         if (Instruction::isCast(CE->getOpcode())) {
 830           Code = bitc::CST_CODE_CE_CAST;
 831           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 832           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 833           Record.push_back(VE.getValueID(C->getOperand(0)));
 834           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 835         } else {
 836           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 837           Code = bitc::CST_CODE_CE_BINOP;
 838           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 839           Record.push_back(VE.getValueID(C->getOperand(0)));
 840           Record.push_back(VE.getValueID(C->getOperand(1)));
 841           uint64_t Flags = GetOptimizationFlags(CE);
 842           if (Flags != 0)
 843             Record.push_back(Flags);
 844         }
 845         break;
 846       case Instruction::GetElementPtr:
 847         Code = bitc::CST_CODE_CE_GEP;
 848         if (cast<GEPOperator>(C)->isInBounds())
 849           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 850         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 851           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 852           Record.push_back(VE.getValueID(C->getOperand(i)));
 853         }
 854         break;
 855       case Instruction::Select:
 856         Code = bitc::CST_CODE_CE_SELECT;
 857         Record.push_back(VE.getValueID(C->getOperand(0)));
 858         Record.push_back(VE.getValueID(C->getOperand(1)));
 859         Record.push_back(VE.getValueID(C->getOperand(2)));
 860         break;
 861       case Instruction::ExtractElement:
 862         Code = bitc::CST_CODE_CE_EXTRACTELT;
 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         break;
 867       case Instruction::InsertElement:
 868         Code = bitc::CST_CODE_CE_INSERTELT;
 869         Record.push_back(VE.getValueID(C->getOperand(0)));
 870         Record.push_back(VE.getValueID(C->getOperand(1)));
 871         Record.push_back(VE.getValueID(C->getOperand(2)));
 872         break;
 873       case Instruction::ShuffleVector:
 874         // If the return type and argument types are the same, this is a
 875         // standard shufflevector instruction.  If the types are different,
 876         // then the shuffle is widening or truncating the input vectors, and
 877         // the argument type must also be encoded.
 878         if (C->getType() == C->getOperand(0)->getType()) {
 879           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 880         } else {
 881           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 882           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 883         }
 884         Record.push_back(VE.getValueID(C->getOperand(0)));
 885         Record.push_back(VE.getValueID(C->getOperand(1)));
 886         Record.push_back(VE.getValueID(C->getOperand(2)));
 887         break;
 888       case Instruction::ICmp:
 889       case Instruction::FCmp:
 890         Code = bitc::CST_CODE_CE_CMP;
 891         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 892         Record.push_back(VE.getValueID(C->getOperand(0)));
 893         Record.push_back(VE.getValueID(C->getOperand(1)));
 894         Record.push_back(CE->getPredicate());
 895         break;
 896       }
 897     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 898       assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
 899              "Malformed blockaddress");
 900       Code = bitc::CST_CODE_BLOCKADDRESS;
 901       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 902       Record.push_back(VE.getValueID(BA->getFunction()));
 903       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 904     } else {
 905       llvm_unreachable("Unknown constant!");
 906     }
 907     Stream.EmitRecord(Code, Record, AbbrevToUse);
 908     Record.clear();
 909   }
 910
 911   Stream.ExitBlock();
 912 }
 913
 914 static void WriteModuleConstants(const ValueEnumerator &VE,
 915                                  BitstreamWriter &Stream) {
 916   const ValueEnumerator::ValueList &Vals = VE.getValues();
 917
 918   // Find the first constant to emit, which is the first non-globalvalue value.
 919   // We know globalvalues have been emitted by WriteModuleInfo.
 920   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 921     if (!isa<GlobalValue>(Vals[i].first)) {
 922       WriteConstants(i, Vals.size(), VE, Stream, true);
 923       return;
 924     }
 925   }
 926 }
 927
 928 /// PushValueAndType - The file has to encode both the value and type id for
 929 /// many values, because we need to know what type to create for forward
 930 /// references.  However, most operands are not forward references, so this type
 931 /// field is not needed.
 932 ///
 933 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 934 /// instruction ID, then it is a forward reference, and it also includes the
 935 /// type ID.
 936 static bool PushValueAndType(const Value *V, unsigned InstID,
 937                              SmallVector<unsigned, 64> &Vals,
 938                              ValueEnumerator &VE) {
 939   unsigned ValID = VE.getValueID(V);
 940   Vals.push_back(ValID);
 941   if (ValID >= InstID) {
 942     Vals.push_back(VE.getTypeID(V->getType()));
 943     return true;
 944   }
 945   return false;
 946 }
 947
 948 /// WriteInstruction - Emit an instruction to the specified stream.
 949 static void WriteInstruction(const Instruction &I, unsigned InstID,
 950                              ValueEnumerator &VE, BitstreamWriter &Stream,
 951                              SmallVector<unsigned, 64> &Vals) {
 952   unsigned Code = 0;
 953   unsigned AbbrevToUse = 0;
 954   VE.setInstructionID(&I);
 955   switch (I.getOpcode()) {
 956   default:
 957     if (Instruction::isCast(I.getOpcode())) {
 958       Code = bitc::FUNC_CODE_INST_CAST;
 959       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 960         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 961       Vals.push_back(VE.getTypeID(I.getType()));
 962       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 963     } else {
 964       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 965       Code = bitc::FUNC_CODE_INST_BINOP;
 966       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 967         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 968       Vals.push_back(VE.getValueID(I.getOperand(1)));
 969       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 970       uint64_t Flags = GetOptimizationFlags(&I);
 971       if (Flags != 0) {
 972         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 973           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 974         Vals.push_back(Flags);
 975       }
 976     }
 977     break;
 978
 979   case Instruction::GetElementPtr:
 980     Code = bitc::FUNC_CODE_INST_GEP;
 981     if (cast<GEPOperator>(&I)->isInBounds())
 982       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 983     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 984       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 985     break;
 986   case Instruction::ExtractValue: {
 987     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 988     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 989     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 990     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 991       Vals.push_back(*i);
 992     break;
 993   }
 994   case Instruction::InsertValue: {
 995     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 996     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 997     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 998     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 999     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1000       Vals.push_back(*i);
1001     break;
1002   }
1003   case Instruction::Select:
1004     Code = bitc::FUNC_CODE_INST_VSELECT;
1005     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1006     Vals.push_back(VE.getValueID(I.getOperand(2)));
1007     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1008     break;
1009   case Instruction::ExtractElement:
1010     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1011     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1012     Vals.push_back(VE.getValueID(I.getOperand(1)));
1013     break;
1014   case Instruction::InsertElement:
1015     Code = bitc::FUNC_CODE_INST_INSERTELT;
1016     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1017     Vals.push_back(VE.getValueID(I.getOperand(1)));
1018     Vals.push_back(VE.getValueID(I.getOperand(2)));
1019     break;
1020   case Instruction::ShuffleVector:
1021     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1022     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1023     Vals.push_back(VE.getValueID(I.getOperand(1)));
1024     Vals.push_back(VE.getValueID(I.getOperand(2)));
1025     break;
1026   case Instruction::ICmp:
1027   case Instruction::FCmp:
1028     // compare returning Int1Ty or vector of Int1Ty
1029     Code = bitc::FUNC_CODE_INST_CMP2;
1030     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1031     Vals.push_back(VE.getValueID(I.getOperand(1)));
1032     Vals.push_back(cast<CmpInst>(I).getPredicate());
1033     break;
1034
1035   case Instruction::Ret:
1036     {
1037       Code = bitc::FUNC_CODE_INST_RET;
1038       unsigned NumOperands = I.getNumOperands();
1039       if (NumOperands == 0)
1040         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1041       else if (NumOperands == 1) {
1042         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1043           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1044       } else {
1045         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1046           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1047       }
1048     }
1049     break;
1050   case Instruction::Br:
1051     {
1052       Code = bitc::FUNC_CODE_INST_BR;
1053       BranchInst &II = cast<BranchInst>(I);
1054       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1055       if (II.isConditional()) {
1056         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1057         Vals.push_back(VE.getValueID(II.getCondition()));
1058       }
1059     }
1060     break;
1061   case Instruction::Switch:
1062     Code = bitc::FUNC_CODE_INST_SWITCH;
1063     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1064     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1065       Vals.push_back(VE.getValueID(I.getOperand(i)));
1066     break;
1067   case Instruction::IndirectBr:
1068     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1069     Vals.push_back(VE.getTypeID(I.getOperand(0)->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::Invoke: {
1075     const InvokeInst *II = cast<InvokeInst>(&I);
1076     const Value *Callee(II->getCalledValue());
1077     const PointerType *PTy = cast<PointerType>(Callee->getType());
1078     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1079     Code = bitc::FUNC_CODE_INST_INVOKE;
1080
1081     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1082     Vals.push_back(II->getCallingConv());
1083     Vals.push_back(VE.getValueID(II->getNormalDest()));
1084     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1085     PushValueAndType(Callee, InstID, Vals, VE);
1086
1087     // Emit value #'s for the fixed parameters.
1088     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1089       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1090
1091     // Emit type/value pairs for varargs params.
1092     if (FTy->isVarArg()) {
1093       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1094            i != e; ++i)
1095         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1096     }
1097     break;
1098   }
1099   case Instruction::Unwind:
1100     Code = bitc::FUNC_CODE_INST_UNWIND;
1101     break;
1102   case Instruction::Unreachable:
1103     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1104     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1105     break;
1106
1107   case Instruction::PHI:
1108     Code = bitc::FUNC_CODE_INST_PHI;
1109     Vals.push_back(VE.getTypeID(I.getType()));
1110     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1111       Vals.push_back(VE.getValueID(I.getOperand(i)));
1112     break;
1113
1114   case Instruction::Alloca:
1115     Code = bitc::FUNC_CODE_INST_ALLOCA;
1116     Vals.push_back(VE.getTypeID(I.getType()));
1117     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1118     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1119     break;
1120
1121   case Instruction::Load:
1122     Code = bitc::FUNC_CODE_INST_LOAD;
1123     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1124       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1125
1126     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1127     Vals.push_back(cast<LoadInst>(I).isVolatile());
1128     break;
1129   case Instruction::Store:
1130     Code = bitc::FUNC_CODE_INST_STORE2;
1131     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1132     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1133     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1134     Vals.push_back(cast<StoreInst>(I).isVolatile());
1135     break;
1136   case Instruction::Call: {
1137     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1138     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1139
1140     Code = bitc::FUNC_CODE_INST_CALL;
1141
1142     const CallInst *CI = cast<CallInst>(&I);
1143     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1144     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1145     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1146
1147     // Emit value #'s for the fixed parameters.
1148     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1149       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1150
1151     // Emit type/value pairs for varargs params.
1152     if (FTy->isVarArg()) {
1153       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1154       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1155            i != e; ++i)
1156         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1157     }
1158     break;
1159   }
1160   case Instruction::VAArg:
1161     Code = bitc::FUNC_CODE_INST_VAARG;
1162     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1163     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1164     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1165     break;
1166   }
1167
1168   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1169   Vals.clear();
1170 }
1171
1172 // Emit names for globals/functions etc.
1173 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1174                                   const ValueEnumerator &VE,
1175                                   BitstreamWriter &Stream) {
1176   if (VST.empty()) return;
1177   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1178
1179   // FIXME: Set up the abbrev, we know how many values there are!
1180   // FIXME: We know if the type names can use 7-bit ascii.
1181   SmallVector<unsigned, 64> NameVals;
1182
1183   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1184        SI != SE; ++SI) {
1185
1186     const ValueName &Name = *SI;
1187
1188     // Figure out the encoding to use for the name.
1189     bool is7Bit = true;
1190     bool isChar6 = true;
1191     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1192          C != E; ++C) {
1193       if (isChar6)
1194         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1195       if ((unsigned char)*C & 128) {
1196         is7Bit = false;
1197         break;  // don't bother scanning the rest.
1198       }
1199     }
1200
1201     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1202
1203     // VST_ENTRY:   [valueid, namechar x N]
1204     // VST_BBENTRY: [bbid, namechar x N]
1205     unsigned Code;
1206     if (isa<BasicBlock>(SI->getValue())) {
1207       Code = bitc::VST_CODE_BBENTRY;
1208       if (isChar6)
1209         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1210     } else {
1211       Code = bitc::VST_CODE_ENTRY;
1212       if (isChar6)
1213         AbbrevToUse = VST_ENTRY_6_ABBREV;
1214       else if (is7Bit)
1215         AbbrevToUse = VST_ENTRY_7_ABBREV;
1216     }
1217
1218     NameVals.push_back(VE.getValueID(SI->getValue()));
1219     for (const char *P = Name.getKeyData(),
1220          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1221       NameVals.push_back((unsigned char)*P);
1222
1223     // Emit the finished record.
1224     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1225     NameVals.clear();
1226   }
1227   Stream.ExitBlock();
1228 }
1229
1230 /// WriteFunction - Emit a function body to the module stream.
1231 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1232                           BitstreamWriter &Stream) {
1233   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1234   VE.incorporateFunction(F);
1235
1236   SmallVector<unsigned, 64> Vals;
1237
1238   // Emit the number of basic blocks, so the reader can create them ahead of
1239   // time.
1240   Vals.push_back(VE.getBasicBlocks().size());
1241   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1242   Vals.clear();
1243
1244   // If there are function-local constants, emit them now.
1245   unsigned CstStart, CstEnd;
1246   VE.getFunctionConstantRange(CstStart, CstEnd);
1247   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1248
1249   // If there is function-local metadata, emit it now.
1250   WriteFunctionLocalMetadata(F, VE, Stream);
1251
1252   // Keep a running idea of what the instruction ID is.
1253   unsigned InstID = CstEnd;
1254
1255   bool NeedsMetadataAttachment = false;
1256
1257   DebugLoc LastDL;
1258
1259   // Finally, emit all the instructions, in order.
1260   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1261     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1262          I != E; ++I) {
1263       WriteInstruction(*I, InstID, VE, Stream, Vals);
1264
1265       if (!I->getType()->isVoidTy())
1266         ++InstID;
1267
1268       // If the instruction has metadata, write a metadata attachment later.
1269       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1270
1271       // If the instruction has a debug location, emit it.
1272       DebugLoc DL = I->getDebugLoc();
1273       if (DL.isUnknown()) {
1274         // nothing todo.
1275       } else if (DL == LastDL) {
1276         // Just repeat the same debug loc as last time.
1277         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1278       } else {
1279         MDNode *Scope, *IA;
1280         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1281
1282         Vals.push_back(DL.getLine());
1283         Vals.push_back(DL.getCol());
1284         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1285         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1286         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1287         Vals.clear();
1288
1289         LastDL = DL;
1290       }
1291     }
1292
1293   // Emit names for all the instructions etc.
1294   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1295
1296   if (NeedsMetadataAttachment)
1297     WriteMetadataAttachment(F, VE, Stream);
1298   VE.purgeFunction();
1299   Stream.ExitBlock();
1300 }
1301
1302 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1303 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1304                                  const ValueEnumerator &VE,
1305                                  BitstreamWriter &Stream) {
1306   if (TST.empty()) return;
1307
1308   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1309
1310   // 7-bit fixed width VST_CODE_ENTRY strings.
1311   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1312   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1313   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1314                             Log2_32_Ceil(VE.getTypes().size()+1)));
1315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1316   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1317   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1318
1319   SmallVector<unsigned, 64> NameVals;
1320
1321   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1322        TI != TE; ++TI) {
1323     // TST_ENTRY: [typeid, namechar x N]
1324     NameVals.push_back(VE.getTypeID(TI->second));
1325
1326     const std::string &Str = TI->first;
1327     bool is7Bit = true;
1328     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1329       NameVals.push_back((unsigned char)Str[i]);
1330       if (Str[i] & 128)
1331         is7Bit = false;
1332     }
1333
1334     // Emit the finished record.
1335     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1336     NameVals.clear();
1337   }
1338
1339   Stream.ExitBlock();
1340 }
1341
1342 // Emit blockinfo, which defines the standard abbreviations etc.
1343 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1344   // We only want to emit block info records for blocks that have multiple
1345   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1346   // blocks can defined their abbrevs inline.
1347   Stream.EnterBlockInfoBlock(2);
1348
1349   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1350     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1355     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1356                                    Abbv) != VST_ENTRY_8_ABBREV)
1357       llvm_unreachable("Unexpected abbrev ordering!");
1358   }
1359
1360   { // 7-bit fixed width VST_ENTRY strings.
1361     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1362     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1366     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1367                                    Abbv) != VST_ENTRY_7_ABBREV)
1368       llvm_unreachable("Unexpected abbrev ordering!");
1369   }
1370   { // 6-bit char6 VST_ENTRY strings.
1371     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1372     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1376     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1377                                    Abbv) != VST_ENTRY_6_ABBREV)
1378       llvm_unreachable("Unexpected abbrev ordering!");
1379   }
1380   { // 6-bit char6 VST_BBENTRY strings.
1381     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1382     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1386     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1387                                    Abbv) != VST_BBENTRY_6_ABBREV)
1388       llvm_unreachable("Unexpected abbrev ordering!");
1389   }
1390
1391
1392
1393   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1394     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1395     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1397                               Log2_32_Ceil(VE.getTypes().size()+1)));
1398     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1399                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1400       llvm_unreachable("Unexpected abbrev ordering!");
1401   }
1402
1403   { // INTEGER abbrev for CONSTANTS_BLOCK.
1404     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1405     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1407     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1408                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1409       llvm_unreachable("Unexpected abbrev ordering!");
1410   }
1411
1412   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1413     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1414     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1417                               Log2_32_Ceil(VE.getTypes().size()+1)));
1418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1419
1420     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1421                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1422       llvm_unreachable("Unexpected abbrev ordering!");
1423   }
1424   { // NULL abbrev for CONSTANTS_BLOCK.
1425     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1426     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1427     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1428                                    Abbv) != CONSTANTS_NULL_Abbrev)
1429       llvm_unreachable("Unexpected abbrev ordering!");
1430   }
1431
1432   // FIXME: This should only use space for first class types!
1433
1434   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1435     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1436     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1440     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1441                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1442       llvm_unreachable("Unexpected abbrev ordering!");
1443   }
1444   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1445     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1446     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1450     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1451                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1452       llvm_unreachable("Unexpected abbrev ordering!");
1453   }
1454   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1455     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1456     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1459     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1461     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1462                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1463       llvm_unreachable("Unexpected abbrev ordering!");
1464   }
1465   { // INST_CAST abbrev for FUNCTION_BLOCK.
1466     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1467     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1470                               Log2_32_Ceil(VE.getTypes().size()+1)));
1471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1472     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1473                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1474       llvm_unreachable("Unexpected abbrev ordering!");
1475   }
1476
1477   { // INST_RET abbrev for FUNCTION_BLOCK.
1478     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1479     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1480     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1481                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1482       llvm_unreachable("Unexpected abbrev ordering!");
1483   }
1484   { // INST_RET abbrev for FUNCTION_BLOCK.
1485     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1486     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1488     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1489                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1490       llvm_unreachable("Unexpected abbrev ordering!");
1491   }
1492   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1493     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1494     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1495     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1496                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1497       llvm_unreachable("Unexpected abbrev ordering!");
1498   }
1499
1500   Stream.ExitBlock();
1501 }
1502
1503
1504 /// WriteModule - Emit the specified module to the bitstream.
1505 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1506   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1507
1508   // Emit the version number if it is non-zero.
1509   if (CurVersion) {
1510     SmallVector<unsigned, 1> Vals;
1511     Vals.push_back(CurVersion);
1512     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1513   }
1514
1515   // Analyze the module, enumerating globals, functions, etc.
1516   ValueEnumerator VE(M);
1517
1518   // Emit blockinfo, which defines the standard abbreviations etc.
1519   WriteBlockInfo(VE, Stream);
1520
1521   // Emit information about parameter attributes.
1522   WriteAttributeTable(VE, Stream);
1523
1524   // Emit information describing all of the types in the module.
1525   WriteTypeTable(VE, Stream);
1526
1527   // Emit top-level description of module, including target triple, inline asm,
1528   // descriptors for global variables, and function prototype info.
1529   WriteModuleInfo(M, VE, Stream);
1530
1531   // Emit constants.
1532   WriteModuleConstants(VE, Stream);
1533
1534   // Emit metadata.
1535   WriteModuleMetadata(VE, Stream);
1536
1537   // Emit function bodies.
1538   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1539     if (!I->isDeclaration())
1540       WriteFunction(*I, VE, Stream);
1541
1542   // Emit metadata.
1543   WriteModuleMetadataStore(M, Stream);
1544
1545   // Emit the type symbol table information.
1546   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1547
1548   // Emit names for globals/functions etc.
1549   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1550
1551   Stream.ExitBlock();
1552 }
1553
1554 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1555 /// header and trailer to make it compatible with the system archiver.  To do
1556 /// this we emit the following header, and then emit a trailer that pads the
1557 /// file out to be a multiple of 16 bytes.
1558 ///
1559 /// struct bc_header {
1560 ///   uint32_t Magic;         // 0x0B17C0DE
1561 ///   uint32_t Version;       // Version, currently always 0.
1562 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1563 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1564 ///   uint32_t CPUType;       // CPU specifier.
1565 ///   ... potentially more later ...
1566 /// };
1567 enum {
1568   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1569   DarwinBCHeaderSize = 5*4
1570 };
1571
1572 /// isARMTriplet - Return true if the triplet looks like:
1573 /// arm-*, thumb-*, armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*.
1574 static bool isARMTriplet(const std::string &TT) {
1575   size_t Pos = 0;
1576   size_t Size = TT.size();
1577   if (Size >= 6 &&
1578       TT[0] == 't' && TT[1] == 'h' && TT[2] == 'u' &&
1579       TT[3] == 'm' && TT[4] == 'b')
1580     Pos = 5;
1581   else if (Size >= 4 && TT[0] == 'a' && TT[1] == 'r' && TT[2] == 'm')
1582     Pos = 3;
1583   else
1584     return false;
1585
1586   if (TT[Pos] == '-')
1587     return true;
1588   else if (TT[Pos] == 'v') {
1589     if (Size >= Pos+4 &&
1590         TT[Pos+1] == '6' && TT[Pos+2] == 't' && TT[Pos+3] == '2')
1591       return true;
1592     else if (Size >= Pos+4 &&
1593              TT[Pos+1] == '5' && TT[Pos+2] == 't' && TT[Pos+3] == 'e')
1594       return true;
1595   } else
1596     return false;
1597   while (++Pos < Size && TT[Pos] != '-') {
1598     if (!isdigit(TT[Pos]))
1599       return false;
1600   }
1601   return true;
1602 }
1603
1604 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1605                                const std::string &TT) {
1606   unsigned CPUType = ~0U;
1607
1608   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1609   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1610   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1611   // specific constants here because they are implicitly part of the Darwin ABI.
1612   enum {
1613     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1614     DARWIN_CPU_TYPE_X86        = 7,
1615     DARWIN_CPU_TYPE_ARM        = 12,
1616     DARWIN_CPU_TYPE_POWERPC    = 18
1617   };
1618
1619   if (TT.find("x86_64-") == 0)
1620     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1621   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1622            TT[4] == '-' && TT[1] - '3' < 6)
1623     CPUType = DARWIN_CPU_TYPE_X86;
1624   else if (TT.find("powerpc-") == 0)
1625     CPUType = DARWIN_CPU_TYPE_POWERPC;
1626   else if (TT.find("powerpc64-") == 0)
1627     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1628   else if (isARMTriplet(TT))
1629     CPUType = DARWIN_CPU_TYPE_ARM;
1630
1631   // Traditional Bitcode starts after header.
1632   unsigned BCOffset = DarwinBCHeaderSize;
1633
1634   Stream.Emit(0x0B17C0DE, 32);
1635   Stream.Emit(0         , 32);  // Version.
1636   Stream.Emit(BCOffset  , 32);
1637   Stream.Emit(0         , 32);  // Filled in later.
1638   Stream.Emit(CPUType   , 32);
1639 }
1640
1641 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1642 /// finalize the header.
1643 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1644   // Update the size field in the header.
1645   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1646
1647   // If the file is not a multiple of 16 bytes, insert dummy padding.
1648   while (BufferSize & 15) {
1649     Stream.Emit(0, 8);
1650     ++BufferSize;
1651   }
1652 }
1653
1654
1655 /// WriteBitcodeToFile - Write the specified module to the specified output
1656 /// stream.
1657 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1658   std::vector<unsigned char> Buffer;
1659   BitstreamWriter Stream(Buffer);
1660
1661   Buffer.reserve(256*1024);
1662
1663   WriteBitcodeToStream( M, Stream );
1664
1665   // If writing to stdout, set binary mode.
1666   if (&llvm::outs() == &Out)
1667     sys::Program::ChangeStdoutToBinary();
1668
1669   // Write the generated bitstream to "Out".
1670   Out.write((char*)&Buffer.front(), Buffer.size());
1671
1672   // Make sure it hits disk now.
1673   Out.flush();
1674 }
1675
1676 /// WriteBitcodeToStream - Write the specified module to the specified output
1677 /// stream.
1678 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1679   // If this is darwin, emit a file header and trailer if needed.
1680   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1681   if (isDarwin)
1682     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1683
1684   // Emit the file header.
1685   Stream.Emit((unsigned)'B', 8);
1686   Stream.Emit((unsigned)'C', 8);
1687   Stream.Emit(0x0, 4);
1688   Stream.Emit(0xC, 4);
1689   Stream.Emit(0xE, 4);
1690   Stream.Emit(0xD, 4);
1691
1692   // Emit the module.
1693   WriteModule(M, Stream);
1694
1695   if (isDarwin)
1696     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1697 }