lib/Bitcode/Writer/BitcodeWriter.cpp

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