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/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/System/Program.h"
  28 using namespace llvm;
  29
  30 /// These are manifest constants used by the bitcode writer. They do not need to
  31 /// be kept in sync with the reader, but need to be consistent within this file.
  32 enum {
  33   CurVersion = 0,
  34
  35   // VALUE_SYMTAB_BLOCK abbrev id's.
  36   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  37   VST_ENTRY_7_ABBREV,
  38   VST_ENTRY_6_ABBREV,
  39   VST_BBENTRY_6_ABBREV,
  40
  41   // CONSTANTS_BLOCK abbrev id's.
  42   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  43   CONSTANTS_INTEGER_ABBREV,
  44   CONSTANTS_CE_CAST_Abbrev,
  45   CONSTANTS_NULL_Abbrev,
  46
  47   // FUNCTION_BLOCK abbrev id's.
  48   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  49   FUNCTION_INST_BINOP_ABBREV,
  50   FUNCTION_INST_CAST_ABBREV,
  51   FUNCTION_INST_RET_VOID_ABBREV,
  52   FUNCTION_INST_RET_VAL_ABBREV,
  53   FUNCTION_INST_UNREACHABLE_ABBREV
  54 };
  55
  56
  57 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  58   switch (Opcode) {
  59   default: assert(0 && "Unknown cast instruction!");
  60   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  61   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  62   case Instruction::SExt    : return bitc::CAST_SEXT;
  63   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  64   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  65   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  66   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  67   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  68   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  69   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  70   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  71   case Instruction::BitCast : return bitc::CAST_BITCAST;
  72   }
  73 }
  74
  75 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  76   switch (Opcode) {
  77   default: assert(0 && "Unknown binary instruction!");
  78   case Instruction::Add:  return bitc::BINOP_ADD;
  79   case Instruction::Sub:  return bitc::BINOP_SUB;
  80   case Instruction::Mul:  return bitc::BINOP_MUL;
  81   case Instruction::UDiv: return bitc::BINOP_UDIV;
  82   case Instruction::FDiv:
  83   case Instruction::SDiv: return bitc::BINOP_SDIV;
  84   case Instruction::URem: return bitc::BINOP_UREM;
  85   case Instruction::FRem:
  86   case Instruction::SRem: return bitc::BINOP_SREM;
  87   case Instruction::Shl:  return bitc::BINOP_SHL;
  88   case Instruction::LShr: return bitc::BINOP_LSHR;
  89   case Instruction::AShr: return bitc::BINOP_ASHR;
  90   case Instruction::And:  return bitc::BINOP_AND;
  91   case Instruction::Or:   return bitc::BINOP_OR;
  92   case Instruction::Xor:  return bitc::BINOP_XOR;
  93   }
  94 }
  95
  96
  97
  98 static void WriteStringRecord(unsigned Code, const std::string &Str,
  99                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 100   SmallVector<unsigned, 64> Vals;
 101
 102   // Code: [strchar x N]
 103   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 104     Vals.push_back(Str[i]);
 105
 106   // Emit the finished record.
 107   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 108 }
 109
 110 // Emit information about parameter attributes.
 111 static void WriteParamAttrTable(const ValueEnumerator &VE,
 112                                 BitstreamWriter &Stream) {
 113   const std::vector<PAListPtr> &Attrs = VE.getParamAttrs();
 114   if (Attrs.empty()) return;
 115
 116   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 117
 118   SmallVector<uint64_t, 64> Record;
 119   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 120     const PAListPtr &A = Attrs[i];
 121     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 122       const ParamAttrsWithIndex &PAWI = A.getSlot(i);
 123       Record.push_back(PAWI.Index);
 124       Record.push_back(PAWI.Attrs);
 125     }
 126
 127     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 128     Record.clear();
 129   }
 130
 131   Stream.ExitBlock();
 132 }
 133
 134 /// WriteTypeTable - Write out the type table for a module.
 135 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 136   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 137
 138   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 139   SmallVector<uint64_t, 64> TypeVals;
 140
 141   // Abbrev for TYPE_CODE_POINTER.
 142   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 143   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 145                             Log2_32_Ceil(VE.getTypes().size()+1)));
 146   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 147   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 148
 149   // Abbrev for TYPE_CODE_FUNCTION.
 150   Abbv = new BitCodeAbbrev();
 151   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 153   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 156                             Log2_32_Ceil(VE.getTypes().size()+1)));
 157   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 158
 159   // Abbrev for TYPE_CODE_STRUCT.
 160   Abbv = new BitCodeAbbrev();
 161   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 165                             Log2_32_Ceil(VE.getTypes().size()+1)));
 166   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 167
 168   // Abbrev for TYPE_CODE_ARRAY.
 169   Abbv = new BitCodeAbbrev();
 170   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 173                             Log2_32_Ceil(VE.getTypes().size()+1)));
 174   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 175
 176   // Emit an entry count so the reader can reserve space.
 177   TypeVals.push_back(TypeList.size());
 178   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 179   TypeVals.clear();
 180
 181   // Loop over all of the types, emitting each in turn.
 182   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 183     const Type *T = TypeList[i].first;
 184     int AbbrevToUse = 0;
 185     unsigned Code = 0;
 186
 187     switch (T->getTypeID()) {
 188     default: assert(0 && "Unknown type!");
 189     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 190     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 191     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 192     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 193     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 194     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 195     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 196     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 197     case Type::IntegerTyID:
 198       // INTEGER: [width]
 199       Code = bitc::TYPE_CODE_INTEGER;
 200       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 201       break;
 202     case Type::PointerTyID: {
 203       const PointerType *PTy = cast<PointerType>(T);
 204       // POINTER: [pointee type, address space]
 205       Code = bitc::TYPE_CODE_POINTER;
 206       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 207       unsigned AddressSpace = PTy->getAddressSpace();
 208       TypeVals.push_back(AddressSpace);
 209       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 210       break;
 211     }
 212     case Type::FunctionTyID: {
 213       const FunctionType *FT = cast<FunctionType>(T);
 214       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 215       Code = bitc::TYPE_CODE_FUNCTION;
 216       TypeVals.push_back(FT->isVarArg());
 217       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 218       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 219       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 220         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 221       AbbrevToUse = FunctionAbbrev;
 222       break;
 223     }
 224     case Type::StructTyID: {
 225       const StructType *ST = cast<StructType>(T);
 226       // STRUCT: [ispacked, eltty x N]
 227       Code = bitc::TYPE_CODE_STRUCT;
 228       TypeVals.push_back(ST->isPacked());
 229       // Output all of the element types.
 230       for (StructType::element_iterator I = ST->element_begin(),
 231            E = ST->element_end(); I != E; ++I)
 232         TypeVals.push_back(VE.getTypeID(*I));
 233       AbbrevToUse = StructAbbrev;
 234       break;
 235     }
 236     case Type::ArrayTyID: {
 237       const ArrayType *AT = cast<ArrayType>(T);
 238       // ARRAY: [numelts, eltty]
 239       Code = bitc::TYPE_CODE_ARRAY;
 240       TypeVals.push_back(AT->getNumElements());
 241       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 242       AbbrevToUse = ArrayAbbrev;
 243       break;
 244     }
 245     case Type::VectorTyID: {
 246       const VectorType *VT = cast<VectorType>(T);
 247       // VECTOR [numelts, eltty]
 248       Code = bitc::TYPE_CODE_VECTOR;
 249       TypeVals.push_back(VT->getNumElements());
 250       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 251       break;
 252     }
 253     }
 254
 255     // Emit the finished record.
 256     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 257     TypeVals.clear();
 258   }
 259
 260   Stream.ExitBlock();
 261 }
 262
 263 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 264   switch (GV->getLinkage()) {
 265   default: assert(0 && "Invalid linkage!");
 266   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 267   case GlobalValue::ExternalLinkage:     return 0;
 268   case GlobalValue::WeakLinkage:         return 1;
 269   case GlobalValue::AppendingLinkage:    return 2;
 270   case GlobalValue::InternalLinkage:     return 3;
 271   case GlobalValue::LinkOnceLinkage:     return 4;
 272   case GlobalValue::DLLImportLinkage:    return 5;
 273   case GlobalValue::DLLExportLinkage:    return 6;
 274   case GlobalValue::ExternalWeakLinkage: return 7;
 275   case GlobalValue::CommonLinkage:       return 8;
 276   }
 277 }
 278
 279 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 280   switch (GV->getVisibility()) {
 281   default: assert(0 && "Invalid visibility!");
 282   case GlobalValue::DefaultVisibility:   return 0;
 283   case GlobalValue::HiddenVisibility:    return 1;
 284   case GlobalValue::ProtectedVisibility: return 2;
 285   }
 286 }
 287
 288 // Emit top-level description of module, including target triple, inline asm,
 289 // descriptors for global variables, and function prototype info.
 290 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 291                             BitstreamWriter &Stream) {
 292   // Emit the list of dependent libraries for the Module.
 293   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 294     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 295
 296   // Emit various pieces of data attached to a module.
 297   if (!M->getTargetTriple().empty())
 298     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 299                       0/*TODO*/, Stream);
 300   if (!M->getDataLayout().empty())
 301     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 302                       0/*TODO*/, Stream);
 303   if (!M->getModuleInlineAsm().empty())
 304     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 305                       0/*TODO*/, Stream);
 306
 307   // Emit information about sections and GC, computing how many there are. Also
 308   // compute the maximum alignment value.
 309   std::map<std::string, unsigned> SectionMap;
 310   std::map<std::string, unsigned> GCMap;
 311   unsigned MaxAlignment = 0;
 312   unsigned MaxGlobalType = 0;
 313   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 314        GV != E; ++GV) {
 315     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 316     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 317
 318     if (!GV->hasSection()) continue;
 319     // Give section names unique ID's.
 320     unsigned &Entry = SectionMap[GV->getSection()];
 321     if (Entry != 0) continue;
 322     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 323                       0/*TODO*/, Stream);
 324     Entry = SectionMap.size();
 325   }
 326   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 327     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 328     if (F->hasSection()) {
 329       // Give section names unique ID's.
 330       unsigned &Entry = SectionMap[F->getSection()];
 331       if (!Entry) {
 332         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 333                           0/*TODO*/, Stream);
 334         Entry = SectionMap.size();
 335       }
 336     }
 337     if (F->hasGC()) {
 338       // Same for GC names.
 339       unsigned &Entry = GCMap[F->getGC()];
 340       if (!Entry) {
 341         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 342                           0/*TODO*/, Stream);
 343         Entry = GCMap.size();
 344       }
 345     }
 346   }
 347
 348   // Emit abbrev for globals, now that we know # sections and max alignment.
 349   unsigned SimpleGVarAbbrev = 0;
 350   if (!M->global_empty()) {
 351     // Add an abbrev for common globals with no visibility or thread localness.
 352     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 353     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 355                               Log2_32_Ceil(MaxGlobalType+1)));
 356     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 359     if (MaxAlignment == 0)                                      // Alignment.
 360       Abbv->Add(BitCodeAbbrevOp(0));
 361     else {
 362       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 363       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 364                                Log2_32_Ceil(MaxEncAlignment+1)));
 365     }
 366     if (SectionMap.empty())                                    // Section.
 367       Abbv->Add(BitCodeAbbrevOp(0));
 368     else
 369       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 370                                Log2_32_Ceil(SectionMap.size()+1)));
 371     // Don't bother emitting vis + thread local.
 372     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 373   }
 374
 375   // Emit the global variable information.
 376   SmallVector<unsigned, 64> Vals;
 377   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 378        GV != E; ++GV) {
 379     unsigned AbbrevToUse = 0;
 380
 381     // GLOBALVAR: [type, isconst, initid,
 382     //             linkage, alignment, section, visibility, threadlocal]
 383     Vals.push_back(VE.getTypeID(GV->getType()));
 384     Vals.push_back(GV->isConstant());
 385     Vals.push_back(GV->isDeclaration() ? 0 :
 386                    (VE.getValueID(GV->getInitializer()) + 1));
 387     Vals.push_back(getEncodedLinkage(GV));
 388     Vals.push_back(Log2_32(GV->getAlignment())+1);
 389     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 390     if (GV->isThreadLocal() ||
 391         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 392       Vals.push_back(getEncodedVisibility(GV));
 393       Vals.push_back(GV->isThreadLocal());
 394     } else {
 395       AbbrevToUse = SimpleGVarAbbrev;
 396     }
 397
 398     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 399     Vals.clear();
 400   }
 401
 402   // Emit the function proto information.
 403   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 404     // FUNCTION:  [type, callingconv, isproto, paramattr,
 405     //             linkage, alignment, section, visibility, gc]
 406     Vals.push_back(VE.getTypeID(F->getType()));
 407     Vals.push_back(F->getCallingConv());
 408     Vals.push_back(F->isDeclaration());
 409     Vals.push_back(getEncodedLinkage(F));
 410     Vals.push_back(VE.getParamAttrID(F->getParamAttrs()));
 411     Vals.push_back(Log2_32(F->getAlignment())+1);
 412     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 413     Vals.push_back(getEncodedVisibility(F));
 414     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 415     Vals.push_back(F->getNotes());
 416
 417     unsigned AbbrevToUse = 0;
 418     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 419     Vals.clear();
 420   }
 421
 422
 423   // Emit the alias information.
 424   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 425        AI != E; ++AI) {
 426     Vals.push_back(VE.getTypeID(AI->getType()));
 427     Vals.push_back(VE.getValueID(AI->getAliasee()));
 428     Vals.push_back(getEncodedLinkage(AI));
 429     Vals.push_back(getEncodedVisibility(AI));
 430     unsigned AbbrevToUse = 0;
 431     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 432     Vals.clear();
 433   }
 434 }
 435
 436
 437 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 438                            const ValueEnumerator &VE,
 439                            BitstreamWriter &Stream, bool isGlobal) {
 440   if (FirstVal == LastVal) return;
 441
 442   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 443
 444   unsigned AggregateAbbrev = 0;
 445   unsigned String8Abbrev = 0;
 446   unsigned CString7Abbrev = 0;
 447   unsigned CString6Abbrev = 0;
 448   // If this is a constant pool for the module, emit module-specific abbrevs.
 449   if (isGlobal) {
 450     // Abbrev for CST_CODE_AGGREGATE.
 451     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 452     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 455     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 456
 457     // Abbrev for CST_CODE_STRING.
 458     Abbv = new BitCodeAbbrev();
 459     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 462     String8Abbrev = Stream.EmitAbbrev(Abbv);
 463     // Abbrev for CST_CODE_CSTRING.
 464     Abbv = new BitCodeAbbrev();
 465     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 468     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 469     // Abbrev for CST_CODE_CSTRING.
 470     Abbv = new BitCodeAbbrev();
 471     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 474     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 475   }
 476
 477   SmallVector<uint64_t, 64> Record;
 478
 479   const ValueEnumerator::ValueList &Vals = VE.getValues();
 480   const Type *LastTy = 0;
 481   for (unsigned i = FirstVal; i != LastVal; ++i) {
 482     const Value *V = Vals[i].first;
 483     // If we need to switch types, do so now.
 484     if (V->getType() != LastTy) {
 485       LastTy = V->getType();
 486       Record.push_back(VE.getTypeID(LastTy));
 487       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 488                         CONSTANTS_SETTYPE_ABBREV);
 489       Record.clear();
 490     }
 491
 492     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 493       Record.push_back(unsigned(IA->hasSideEffects()));
 494
 495       // Add the asm string.
 496       const std::string &AsmStr = IA->getAsmString();
 497       Record.push_back(AsmStr.size());
 498       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 499         Record.push_back(AsmStr[i]);
 500
 501       // Add the constraint string.
 502       const std::string &ConstraintStr = IA->getConstraintString();
 503       Record.push_back(ConstraintStr.size());
 504       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 505         Record.push_back(ConstraintStr[i]);
 506       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 507       Record.clear();
 508       continue;
 509     }
 510     const Constant *C = cast<Constant>(V);
 511     unsigned Code = -1U;
 512     unsigned AbbrevToUse = 0;
 513     if (C->isNullValue()) {
 514       Code = bitc::CST_CODE_NULL;
 515     } else if (isa<UndefValue>(C)) {
 516       Code = bitc::CST_CODE_UNDEF;
 517     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 518       if (IV->getBitWidth() <= 64) {
 519         int64_t V = IV->getSExtValue();
 520         if (V >= 0)
 521           Record.push_back(V << 1);
 522         else
 523           Record.push_back((-V << 1) | 1);
 524         Code = bitc::CST_CODE_INTEGER;
 525         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 526       } else {                             // Wide integers, > 64 bits in size.
 527         // We have an arbitrary precision integer value to write whose
 528         // bit width is > 64. However, in canonical unsigned integer
 529         // format it is likely that the high bits are going to be zero.
 530         // So, we only write the number of active words.
 531         unsigned NWords = IV->getValue().getActiveWords();
 532         const uint64_t *RawWords = IV->getValue().getRawData();
 533         for (unsigned i = 0; i != NWords; ++i) {
 534           int64_t V = RawWords[i];
 535           if (V >= 0)
 536             Record.push_back(V << 1);
 537           else
 538             Record.push_back((-V << 1) | 1);
 539         }
 540         Code = bitc::CST_CODE_WIDE_INTEGER;
 541       }
 542     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 543       Code = bitc::CST_CODE_FLOAT;
 544       const Type *Ty = CFP->getType();
 545       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 546         Record.push_back(CFP->getValueAPF().convertToAPInt().getZExtValue());
 547       } else if (Ty == Type::X86_FP80Ty) {
 548         // api needed to prevent premature destruction
 549         APInt api = CFP->getValueAPF().convertToAPInt();
 550         const uint64_t *p = api.getRawData();
 551         Record.push_back(p[0]);
 552         Record.push_back((uint16_t)p[1]);
 553       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 554         APInt api = CFP->getValueAPF().convertToAPInt();
 555         const uint64_t *p = api.getRawData();
 556         Record.push_back(p[0]);
 557         Record.push_back(p[1]);
 558       } else {
 559         assert (0 && "Unknown FP type!");
 560       }
 561     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 562       // Emit constant strings specially.
 563       unsigned NumOps = C->getNumOperands();
 564       // If this is a null-terminated string, use the denser CSTRING encoding.
 565       if (C->getOperand(NumOps-1)->isNullValue()) {
 566         Code = bitc::CST_CODE_CSTRING;
 567         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 568       } else {
 569         Code = bitc::CST_CODE_STRING;
 570         AbbrevToUse = String8Abbrev;
 571       }
 572       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 573       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 574       for (unsigned i = 0; i != NumOps; ++i) {
 575         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 576         Record.push_back(V);
 577         isCStr7 &= (V & 128) == 0;
 578         if (isCStrChar6)
 579           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 580       }
 581
 582       if (isCStrChar6)
 583         AbbrevToUse = CString6Abbrev;
 584       else if (isCStr7)
 585         AbbrevToUse = CString7Abbrev;
 586     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 587                isa<ConstantVector>(V)) {
 588       Code = bitc::CST_CODE_AGGREGATE;
 589       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 590         Record.push_back(VE.getValueID(C->getOperand(i)));
 591       AbbrevToUse = AggregateAbbrev;
 592     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 593       switch (CE->getOpcode()) {
 594       default:
 595         if (Instruction::isCast(CE->getOpcode())) {
 596           Code = bitc::CST_CODE_CE_CAST;
 597           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 598           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 599           Record.push_back(VE.getValueID(C->getOperand(0)));
 600           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 601         } else {
 602           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 603           Code = bitc::CST_CODE_CE_BINOP;
 604           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 605           Record.push_back(VE.getValueID(C->getOperand(0)));
 606           Record.push_back(VE.getValueID(C->getOperand(1)));
 607         }
 608         break;
 609       case Instruction::GetElementPtr:
 610         Code = bitc::CST_CODE_CE_GEP;
 611         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 612           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 613           Record.push_back(VE.getValueID(C->getOperand(i)));
 614         }
 615         break;
 616       case Instruction::Select:
 617         Code = bitc::CST_CODE_CE_SELECT;
 618         Record.push_back(VE.getValueID(C->getOperand(0)));
 619         Record.push_back(VE.getValueID(C->getOperand(1)));
 620         Record.push_back(VE.getValueID(C->getOperand(2)));
 621         break;
 622       case Instruction::ExtractElement:
 623         Code = bitc::CST_CODE_CE_EXTRACTELT;
 624         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 625         Record.push_back(VE.getValueID(C->getOperand(0)));
 626         Record.push_back(VE.getValueID(C->getOperand(1)));
 627         break;
 628       case Instruction::InsertElement:
 629         Code = bitc::CST_CODE_CE_INSERTELT;
 630         Record.push_back(VE.getValueID(C->getOperand(0)));
 631         Record.push_back(VE.getValueID(C->getOperand(1)));
 632         Record.push_back(VE.getValueID(C->getOperand(2)));
 633         break;
 634       case Instruction::ShuffleVector:
 635         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 636         Record.push_back(VE.getValueID(C->getOperand(0)));
 637         Record.push_back(VE.getValueID(C->getOperand(1)));
 638         Record.push_back(VE.getValueID(C->getOperand(2)));
 639         break;
 640       case Instruction::ICmp:
 641       case Instruction::FCmp:
 642       case Instruction::VICmp:
 643       case Instruction::VFCmp:
 644         Code = bitc::CST_CODE_CE_CMP;
 645         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 646         Record.push_back(VE.getValueID(C->getOperand(0)));
 647         Record.push_back(VE.getValueID(C->getOperand(1)));
 648         Record.push_back(CE->getPredicate());
 649         break;
 650       }
 651     } else {
 652       assert(0 && "Unknown constant!");
 653     }
 654     Stream.EmitRecord(Code, Record, AbbrevToUse);
 655     Record.clear();
 656   }
 657
 658   Stream.ExitBlock();
 659 }
 660
 661 static void WriteModuleConstants(const ValueEnumerator &VE,
 662                                  BitstreamWriter &Stream) {
 663   const ValueEnumerator::ValueList &Vals = VE.getValues();
 664
 665   // Find the first constant to emit, which is the first non-globalvalue value.
 666   // We know globalvalues have been emitted by WriteModuleInfo.
 667   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 668     if (!isa<GlobalValue>(Vals[i].first)) {
 669       WriteConstants(i, Vals.size(), VE, Stream, true);
 670       return;
 671     }
 672   }
 673 }
 674
 675 /// PushValueAndType - The file has to encode both the value and type id for
 676 /// many values, because we need to know what type to create for forward
 677 /// references.  However, most operands are not forward references, so this type
 678 /// field is not needed.
 679 ///
 680 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 681 /// instruction ID, then it is a forward reference, and it also includes the
 682 /// type ID.
 683 static bool PushValueAndType(Value *V, unsigned InstID,
 684                              SmallVector<unsigned, 64> &Vals,
 685                              ValueEnumerator &VE) {
 686   unsigned ValID = VE.getValueID(V);
 687   Vals.push_back(ValID);
 688   if (ValID >= InstID) {
 689     Vals.push_back(VE.getTypeID(V->getType()));
 690     return true;
 691   }
 692   return false;
 693 }
 694
 695 /// WriteInstruction - Emit an instruction to the specified stream.
 696 static void WriteInstruction(const Instruction &I, unsigned InstID,
 697                              ValueEnumerator &VE, BitstreamWriter &Stream,
 698                              SmallVector<unsigned, 64> &Vals) {
 699   unsigned Code = 0;
 700   unsigned AbbrevToUse = 0;
 701   switch (I.getOpcode()) {
 702   default:
 703     if (Instruction::isCast(I.getOpcode())) {
 704       Code = bitc::FUNC_CODE_INST_CAST;
 705       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 706         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 707       Vals.push_back(VE.getTypeID(I.getType()));
 708       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 709     } else {
 710       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 711       Code = bitc::FUNC_CODE_INST_BINOP;
 712       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 713         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 714       Vals.push_back(VE.getValueID(I.getOperand(1)));
 715       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 716     }
 717     break;
 718
 719   case Instruction::GetElementPtr:
 720     Code = bitc::FUNC_CODE_INST_GEP;
 721     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 722       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 723     break;
 724   case Instruction::ExtractValue: {
 725     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 726     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 727     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 728     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 729       Vals.push_back(*i);
 730     break;
 731   }
 732   case Instruction::InsertValue: {
 733     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 734     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 735     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 736     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 737     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 738       Vals.push_back(*i);
 739     break;
 740   }
 741   case Instruction::Select:
 742     Code = bitc::FUNC_CODE_INST_SELECT;
 743     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 744     Vals.push_back(VE.getValueID(I.getOperand(2)));
 745     Vals.push_back(VE.getValueID(I.getOperand(0)));
 746     break;
 747   case Instruction::ExtractElement:
 748     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 749     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 750     Vals.push_back(VE.getValueID(I.getOperand(1)));
 751     break;
 752   case Instruction::InsertElement:
 753     Code = bitc::FUNC_CODE_INST_INSERTELT;
 754     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 755     Vals.push_back(VE.getValueID(I.getOperand(1)));
 756     Vals.push_back(VE.getValueID(I.getOperand(2)));
 757     break;
 758   case Instruction::ShuffleVector:
 759     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 760     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 761     Vals.push_back(VE.getValueID(I.getOperand(1)));
 762     Vals.push_back(VE.getValueID(I.getOperand(2)));
 763     break;
 764   case Instruction::ICmp:
 765   case Instruction::FCmp:
 766   case Instruction::VICmp:
 767   case Instruction::VFCmp:
 768     Code = bitc::FUNC_CODE_INST_CMP;
 769     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 770     Vals.push_back(VE.getValueID(I.getOperand(1)));
 771     Vals.push_back(cast<CmpInst>(I).getPredicate());
 772     break;
 773
 774   case Instruction::Ret:
 775     {
 776       Code = bitc::FUNC_CODE_INST_RET;
 777       unsigned NumOperands = I.getNumOperands();
 778       if (NumOperands == 0)
 779         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 780       else if (NumOperands == 1) {
 781         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 782           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 783       } else {
 784         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 785           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 786       }
 787     }
 788     break;
 789   case Instruction::Br:
 790     Code = bitc::FUNC_CODE_INST_BR;
 791     Vals.push_back(VE.getValueID(I.getOperand(0)));
 792     if (cast<BranchInst>(I).isConditional()) {
 793       Vals.push_back(VE.getValueID(I.getOperand(1)));
 794       Vals.push_back(VE.getValueID(I.getOperand(2)));
 795     }
 796     break;
 797   case Instruction::Switch:
 798     Code = bitc::FUNC_CODE_INST_SWITCH;
 799     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 800     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 801       Vals.push_back(VE.getValueID(I.getOperand(i)));
 802     break;
 803   case Instruction::Invoke: {
 804     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 805     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 806     Code = bitc::FUNC_CODE_INST_INVOKE;
 807
 808     const InvokeInst *II = cast<InvokeInst>(&I);
 809     Vals.push_back(VE.getParamAttrID(II->getParamAttrs()));
 810     Vals.push_back(II->getCallingConv());
 811     Vals.push_back(VE.getValueID(I.getOperand(1)));      // normal dest
 812     Vals.push_back(VE.getValueID(I.getOperand(2)));      // unwind dest
 813     PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
 814
 815     // Emit value #'s for the fixed parameters.
 816     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 817       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 818
 819     // Emit type/value pairs for varargs params.
 820     if (FTy->isVarArg()) {
 821       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 822            i != e; ++i)
 823         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 824     }
 825     break;
 826   }
 827   case Instruction::Unwind:
 828     Code = bitc::FUNC_CODE_INST_UNWIND;
 829     break;
 830   case Instruction::Unreachable:
 831     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 832     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 833     break;
 834
 835   case Instruction::PHI:
 836     Code = bitc::FUNC_CODE_INST_PHI;
 837     Vals.push_back(VE.getTypeID(I.getType()));
 838     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 839       Vals.push_back(VE.getValueID(I.getOperand(i)));
 840     break;
 841
 842   case Instruction::Malloc:
 843     Code = bitc::FUNC_CODE_INST_MALLOC;
 844     Vals.push_back(VE.getTypeID(I.getType()));
 845     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 846     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 847     break;
 848
 849   case Instruction::Free:
 850     Code = bitc::FUNC_CODE_INST_FREE;
 851     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 852     break;
 853
 854   case Instruction::Alloca:
 855     Code = bitc::FUNC_CODE_INST_ALLOCA;
 856     Vals.push_back(VE.getTypeID(I.getType()));
 857     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 858     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 859     break;
 860
 861   case Instruction::Load:
 862     Code = bitc::FUNC_CODE_INST_LOAD;
 863     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 864       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 865
 866     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 867     Vals.push_back(cast<LoadInst>(I).isVolatile());
 868     break;
 869   case Instruction::Store:
 870     Code = bitc::FUNC_CODE_INST_STORE2;
 871     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 872     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 873     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 874     Vals.push_back(cast<StoreInst>(I).isVolatile());
 875     break;
 876   case Instruction::Call: {
 877     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 878     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 879
 880     Code = bitc::FUNC_CODE_INST_CALL;
 881
 882     const CallInst *CI = cast<CallInst>(&I);
 883     Vals.push_back(VE.getParamAttrID(CI->getParamAttrs()));
 884     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 885     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 886
 887     // Emit value #'s for the fixed parameters.
 888     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 889       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 890
 891     // Emit type/value pairs for varargs params.
 892     if (FTy->isVarArg()) {
 893       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 894       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 895            i != e; ++i)
 896         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 897     }
 898     break;
 899   }
 900   case Instruction::VAArg:
 901     Code = bitc::FUNC_CODE_INST_VAARG;
 902     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 903     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 904     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 905     break;
 906   }
 907
 908   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 909   Vals.clear();
 910 }
 911
 912 // Emit names for globals/functions etc.
 913 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 914                                   const ValueEnumerator &VE,
 915                                   BitstreamWriter &Stream) {
 916   if (VST.empty()) return;
 917   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 918
 919   // FIXME: Set up the abbrev, we know how many values there are!
 920   // FIXME: We know if the type names can use 7-bit ascii.
 921   SmallVector<unsigned, 64> NameVals;
 922
 923   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 924        SI != SE; ++SI) {
 925
 926     const ValueName &Name = *SI;
 927
 928     // Figure out the encoding to use for the name.
 929     bool is7Bit = true;
 930     bool isChar6 = true;
 931     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 932          C != E; ++C) {
 933       if (isChar6)
 934         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 935       if ((unsigned char)*C & 128) {
 936         is7Bit = false;
 937         break;  // don't bother scanning the rest.
 938       }
 939     }
 940
 941     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 942
 943     // VST_ENTRY:   [valueid, namechar x N]
 944     // VST_BBENTRY: [bbid, namechar x N]
 945     unsigned Code;
 946     if (isa<BasicBlock>(SI->getValue())) {
 947       Code = bitc::VST_CODE_BBENTRY;
 948       if (isChar6)
 949         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 950     } else {
 951       Code = bitc::VST_CODE_ENTRY;
 952       if (isChar6)
 953         AbbrevToUse = VST_ENTRY_6_ABBREV;
 954       else if (is7Bit)
 955         AbbrevToUse = VST_ENTRY_7_ABBREV;
 956     }
 957
 958     NameVals.push_back(VE.getValueID(SI->getValue()));
 959     for (const char *P = Name.getKeyData(),
 960          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 961       NameVals.push_back((unsigned char)*P);
 962
 963     // Emit the finished record.
 964     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 965     NameVals.clear();
 966   }
 967   Stream.ExitBlock();
 968 }
 969
 970 /// WriteFunction - Emit a function body to the module stream.
 971 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 972                           BitstreamWriter &Stream) {
 973   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
 974   VE.incorporateFunction(F);
 975
 976   SmallVector<unsigned, 64> Vals;
 977
 978   // Emit the number of basic blocks, so the reader can create them ahead of
 979   // time.
 980   Vals.push_back(VE.getBasicBlocks().size());
 981   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
 982   Vals.clear();
 983
 984   // If there are function-local constants, emit them now.
 985   unsigned CstStart, CstEnd;
 986   VE.getFunctionConstantRange(CstStart, CstEnd);
 987   WriteConstants(CstStart, CstEnd, VE, Stream, false);
 988
 989   // Keep a running idea of what the instruction ID is.
 990   unsigned InstID = CstEnd;
 991
 992   // Finally, emit all the instructions, in order.
 993   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 994     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 995          I != E; ++I) {
 996       WriteInstruction(*I, InstID, VE, Stream, Vals);
 997       if (I->getType() != Type::VoidTy)
 998         ++InstID;
 999     }
1000
1001   // Emit names for all the instructions etc.
1002   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1003
1004   VE.purgeFunction();
1005   Stream.ExitBlock();
1006 }
1007
1008 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1009 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1010                                  const ValueEnumerator &VE,
1011                                  BitstreamWriter &Stream) {
1012   if (TST.empty()) return;
1013
1014   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1015
1016   // 7-bit fixed width VST_CODE_ENTRY strings.
1017   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1018   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1019   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1020                             Log2_32_Ceil(VE.getTypes().size()+1)));
1021   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1022   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1023   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1024
1025   SmallVector<unsigned, 64> NameVals;
1026
1027   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1028        TI != TE; ++TI) {
1029     // TST_ENTRY: [typeid, namechar x N]
1030     NameVals.push_back(VE.getTypeID(TI->second));
1031
1032     const std::string &Str = TI->first;
1033     bool is7Bit = true;
1034     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1035       NameVals.push_back((unsigned char)Str[i]);
1036       if (Str[i] & 128)
1037         is7Bit = false;
1038     }
1039
1040     // Emit the finished record.
1041     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1042     NameVals.clear();
1043   }
1044
1045   Stream.ExitBlock();
1046 }
1047
1048 // Emit blockinfo, which defines the standard abbreviations etc.
1049 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1050   // We only want to emit block info records for blocks that have multiple
1051   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1052   // blocks can defined their abbrevs inline.
1053   Stream.EnterBlockInfoBlock(2);
1054
1055   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1056     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1057     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1058     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1059     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1060     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1061     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1062                                    Abbv) != VST_ENTRY_8_ABBREV)
1063       assert(0 && "Unexpected abbrev ordering!");
1064   }
1065
1066   { // 7-bit fixed width VST_ENTRY strings.
1067     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1068     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1069     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1070     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1071     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1072     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1073                                    Abbv) != VST_ENTRY_7_ABBREV)
1074       assert(0 && "Unexpected abbrev ordering!");
1075   }
1076   { // 6-bit char6 VST_ENTRY strings.
1077     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1078     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1079     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1080     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1081     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1082     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1083                                    Abbv) != VST_ENTRY_6_ABBREV)
1084       assert(0 && "Unexpected abbrev ordering!");
1085   }
1086   { // 6-bit char6 VST_BBENTRY strings.
1087     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1088     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1089     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1090     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1091     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1092     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1093                                    Abbv) != VST_BBENTRY_6_ABBREV)
1094       assert(0 && "Unexpected abbrev ordering!");
1095   }
1096
1097
1098
1099   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1100     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1101     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1103                               Log2_32_Ceil(VE.getTypes().size()+1)));
1104     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1105                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1106       assert(0 && "Unexpected abbrev ordering!");
1107   }
1108
1109   { // INTEGER abbrev for CONSTANTS_BLOCK.
1110     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1111     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1112     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1113     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1114                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1115       assert(0 && "Unexpected abbrev ordering!");
1116   }
1117
1118   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1119     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1120     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1121     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1122     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1123                               Log2_32_Ceil(VE.getTypes().size()+1)));
1124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1125
1126     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1127                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1128       assert(0 && "Unexpected abbrev ordering!");
1129   }
1130   { // NULL abbrev for CONSTANTS_BLOCK.
1131     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1132     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1133     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1134                                    Abbv) != CONSTANTS_NULL_Abbrev)
1135       assert(0 && "Unexpected abbrev ordering!");
1136   }
1137
1138   // FIXME: This should only use space for first class types!
1139
1140   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1141     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1142     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1143     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1144     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1145     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1146     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1147                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1148       assert(0 && "Unexpected abbrev ordering!");
1149   }
1150   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1151     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1152     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1153     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1154     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1155     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1156     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1157                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1158       assert(0 && "Unexpected abbrev ordering!");
1159   }
1160   { // INST_CAST abbrev for FUNCTION_BLOCK.
1161     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1162     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1165                               Log2_32_Ceil(VE.getTypes().size()+1)));
1166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1167     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1168                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1169       assert(0 && "Unexpected abbrev ordering!");
1170   }
1171
1172   { // INST_RET abbrev for FUNCTION_BLOCK.
1173     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1174     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1175     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1176                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1177       assert(0 && "Unexpected abbrev ordering!");
1178   }
1179   { // INST_RET abbrev for FUNCTION_BLOCK.
1180     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1181     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1183     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1184                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1185       assert(0 && "Unexpected abbrev ordering!");
1186   }
1187   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1188     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1189     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1190     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1191                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1192       assert(0 && "Unexpected abbrev ordering!");
1193   }
1194
1195   Stream.ExitBlock();
1196 }
1197
1198
1199 /// WriteModule - Emit the specified module to the bitstream.
1200 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1201   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1202
1203   // Emit the version number if it is non-zero.
1204   if (CurVersion) {
1205     SmallVector<unsigned, 1> Vals;
1206     Vals.push_back(CurVersion);
1207     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1208   }
1209
1210   // Analyze the module, enumerating globals, functions, etc.
1211   ValueEnumerator VE(M);
1212
1213   // Emit blockinfo, which defines the standard abbreviations etc.
1214   WriteBlockInfo(VE, Stream);
1215
1216   // Emit information about parameter attributes.
1217   WriteParamAttrTable(VE, Stream);
1218
1219   // Emit information describing all of the types in the module.
1220   WriteTypeTable(VE, Stream);
1221
1222   // Emit top-level description of module, including target triple, inline asm,
1223   // descriptors for global variables, and function prototype info.
1224   WriteModuleInfo(M, VE, Stream);
1225
1226   // Emit constants.
1227   WriteModuleConstants(VE, Stream);
1228
1229   // If we have any aggregate values in the value table, purge them - these can
1230   // only be used to initialize global variables.  Doing so makes the value
1231   // namespace smaller for code in functions.
1232   int NumNonAggregates = VE.PurgeAggregateValues();
1233   if (NumNonAggregates != -1) {
1234     SmallVector<unsigned, 1> Vals;
1235     Vals.push_back(NumNonAggregates);
1236     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1237   }
1238
1239   // Emit function bodies.
1240   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1241     if (!I->isDeclaration())
1242       WriteFunction(*I, VE, Stream);
1243
1244   // Emit the type symbol table information.
1245   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1246
1247   // Emit names for globals/functions etc.
1248   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1249
1250   Stream.ExitBlock();
1251 }
1252
1253 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1254 /// header and trailer to make it compatible with the system archiver.  To do
1255 /// this we emit the following header, and then emit a trailer that pads the
1256 /// file out to be a multiple of 16 bytes.
1257 ///
1258 /// struct bc_header {
1259 ///   uint32_t Magic;         // 0x0B17C0DE
1260 ///   uint32_t Version;       // Version, currently always 0.
1261 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1262 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1263 ///   uint32_t CPUType;       // CPU specifier.
1264 ///   ... potentially more later ...
1265 /// };
1266 enum {
1267   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1268   DarwinBCHeaderSize = 5*4
1269 };
1270
1271 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1272                                const std::string &TT) {
1273   unsigned CPUType = ~0U;
1274
1275   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1276   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1277   // specific constants here because they are implicitly part of the Darwin ABI.
1278   enum {
1279     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1280     DARWIN_CPU_TYPE_X86        = 7,
1281     DARWIN_CPU_TYPE_POWERPC    = 18
1282   };
1283
1284   if (TT.find("x86_64-") == 0)
1285     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1286   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1287            TT[4] == '-' && TT[1] - '3' < 6)
1288     CPUType = DARWIN_CPU_TYPE_X86;
1289   else if (TT.find("powerpc-") == 0)
1290     CPUType = DARWIN_CPU_TYPE_POWERPC;
1291   else if (TT.find("powerpc64-") == 0)
1292     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1293
1294   // Traditional Bitcode starts after header.
1295   unsigned BCOffset = DarwinBCHeaderSize;
1296
1297   Stream.Emit(0x0B17C0DE, 32);
1298   Stream.Emit(0         , 32);  // Version.
1299   Stream.Emit(BCOffset  , 32);
1300   Stream.Emit(0         , 32);  // Filled in later.
1301   Stream.Emit(CPUType   , 32);
1302 }
1303
1304 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1305 /// finalize the header.
1306 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1307   // Update the size field in the header.
1308   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1309
1310   // If the file is not a multiple of 16 bytes, insert dummy padding.
1311   while (BufferSize & 15) {
1312     Stream.Emit(0, 8);
1313     ++BufferSize;
1314   }
1315 }
1316
1317
1318 /// WriteBitcodeToFile - Write the specified module to the specified output
1319 /// stream.
1320 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1321   std::vector<unsigned char> Buffer;
1322   BitstreamWriter Stream(Buffer);
1323
1324   Buffer.reserve(256*1024);
1325
1326   // If this is darwin, emit a file header and trailer if needed.
1327   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1328   if (isDarwin)
1329     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1330
1331   // Emit the file header.
1332   Stream.Emit((unsigned)'B', 8);
1333   Stream.Emit((unsigned)'C', 8);
1334   Stream.Emit(0x0, 4);
1335   Stream.Emit(0xC, 4);
1336   Stream.Emit(0xE, 4);
1337   Stream.Emit(0xD, 4);
1338
1339   // Emit the module.
1340   WriteModule(M, Stream);
1341
1342   if (isDarwin)
1343     EmitDarwinBCTrailer(Stream, Buffer.size());
1344
1345
1346   // If writing to stdout, set binary mode.
1347   if (llvm::cout == Out)
1348     sys::Program::ChangeStdoutToBinary();
1349
1350   // Write the generated bitstream to "Out".
1351   Out.write((char*)&Buffer.front(), Buffer.size());
1352
1353   // Make sure it hits disk now.
1354   Out.flush();
1355 }