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