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     default: assert(0 && "Unknown type!");
 187     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 188     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 189     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 190     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 191     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 192     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 193     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 194     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 195     case Type::IntegerTyID:
 196       // INTEGER: [width]
 197       Code = bitc::TYPE_CODE_INTEGER;
 198       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 199       break;
 200     case Type::PointerTyID:
 201       // POINTER: [pointee type]
 202       Code = bitc::TYPE_CODE_POINTER;
 203       TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType()));
 204       AbbrevToUse = PtrAbbrev;
 205       break;
 206
 207     case Type::FunctionTyID: {
 208       const FunctionType *FT = cast<FunctionType>(T);
 209       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 210       Code = bitc::TYPE_CODE_FUNCTION;
 211       TypeVals.push_back(FT->isVarArg());
 212       TypeVals.push_back(VE.getParamAttrID(FT->getParamAttrs()));
 213       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 214       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 215         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 216       AbbrevToUse = FunctionAbbrev;
 217       break;
 218     }
 219     case Type::StructTyID: {
 220       const StructType *ST = cast<StructType>(T);
 221       // STRUCT: [ispacked, eltty x N]
 222       Code = bitc::TYPE_CODE_STRUCT;
 223       TypeVals.push_back(ST->isPacked());
 224       // Output all of the element types.
 225       for (StructType::element_iterator I = ST->element_begin(),
 226            E = ST->element_end(); I != E; ++I)
 227         TypeVals.push_back(VE.getTypeID(*I));
 228       AbbrevToUse = StructAbbrev;
 229       break;
 230     }
 231     case Type::ArrayTyID: {
 232       const ArrayType *AT = cast<ArrayType>(T);
 233       // ARRAY: [numelts, eltty]
 234       Code = bitc::TYPE_CODE_ARRAY;
 235       TypeVals.push_back(AT->getNumElements());
 236       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 237       AbbrevToUse = ArrayAbbrev;
 238       break;
 239     }
 240     case Type::VectorTyID: {
 241       const VectorType *VT = cast<VectorType>(T);
 242       // VECTOR [numelts, eltty]
 243       Code = bitc::TYPE_CODE_VECTOR;
 244       TypeVals.push_back(VT->getNumElements());
 245       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 246       break;
 247     }
 248     }
 249
 250     // Emit the finished record.
 251     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 252     TypeVals.clear();
 253   }
 254
 255   Stream.ExitBlock();
 256 }
 257
 258 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 259   switch (GV->getLinkage()) {
 260   default: assert(0 && "Invalid linkage!");
 261   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 262   case GlobalValue::ExternalLinkage:     return 0;
 263   case GlobalValue::WeakLinkage:         return 1;
 264   case GlobalValue::AppendingLinkage:    return 2;
 265   case GlobalValue::InternalLinkage:     return 3;
 266   case GlobalValue::LinkOnceLinkage:     return 4;
 267   case GlobalValue::DLLImportLinkage:    return 5;
 268   case GlobalValue::DLLExportLinkage:    return 6;
 269   case GlobalValue::ExternalWeakLinkage: return 7;
 270   }
 271 }
 272
 273 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 274   switch (GV->getVisibility()) {
 275   default: assert(0 && "Invalid visibility!");
 276   case GlobalValue::DefaultVisibility:   return 0;
 277   case GlobalValue::HiddenVisibility:    return 1;
 278   case GlobalValue::ProtectedVisibility: return 2;
 279   }
 280 }
 281
 282 // Emit top-level description of module, including target triple, inline asm,
 283 // descriptors for global variables, and function prototype info.
 284 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 285                             BitstreamWriter &Stream) {
 286   // Emit the list of dependent libraries for the Module.
 287   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 288     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 289
 290   // Emit various pieces of data attached to a module.
 291   if (!M->getTargetTriple().empty())
 292     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 293                       0/*TODO*/, Stream);
 294   if (!M->getDataLayout().empty())
 295     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 296                       0/*TODO*/, Stream);
 297   if (!M->getModuleInlineAsm().empty())
 298     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 299                       0/*TODO*/, Stream);
 300
 301   // Emit information about sections, computing how many there are.  Also
 302   // compute the maximum alignment value.
 303   std::map<std::string, unsigned> SectionMap;
 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()) continue;
 322     // Give section names unique ID's.
 323     unsigned &Entry = SectionMap[F->getSection()];
 324     if (Entry != 0) continue;
 325     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 326                       0/*TODO*/, Stream);
 327     Entry = SectionMap.size();
 328   }
 329
 330   // Emit abbrev for globals, now that we know # sections and max alignment.
 331   unsigned SimpleGVarAbbrev = 0;
 332   if (!M->global_empty()) {
 333     // Add an abbrev for common globals with no visibility or thread localness.
 334     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 335     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 336     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 337                               Log2_32_Ceil(MaxGlobalType+1)));
 338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 339     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 340     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));      // Linkage.
 341     if (MaxAlignment == 0)                                      // Alignment.
 342       Abbv->Add(BitCodeAbbrevOp(0));
 343     else {
 344       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 345       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 346                                Log2_32_Ceil(MaxEncAlignment+1)));
 347     }
 348     if (SectionMap.empty())                                    // Section.
 349       Abbv->Add(BitCodeAbbrevOp(0));
 350     else
 351       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 352                                Log2_32_Ceil(SectionMap.size()+1)));
 353     // Don't bother emitting vis + thread local.
 354     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 355   }
 356
 357   // Emit the global variable information.
 358   SmallVector<unsigned, 64> Vals;
 359   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 360        GV != E; ++GV) {
 361     unsigned AbbrevToUse = 0;
 362
 363     // GLOBALVAR: [type, isconst, initid,
 364     //             linkage, alignment, section, visibility, threadlocal]
 365     Vals.push_back(VE.getTypeID(GV->getType()));
 366     Vals.push_back(GV->isConstant());
 367     Vals.push_back(GV->isDeclaration() ? 0 :
 368                    (VE.getValueID(GV->getInitializer()) + 1));
 369     Vals.push_back(getEncodedLinkage(GV));
 370     Vals.push_back(Log2_32(GV->getAlignment())+1);
 371     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 372     if (GV->isThreadLocal() ||
 373         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 374       Vals.push_back(getEncodedVisibility(GV));
 375       Vals.push_back(GV->isThreadLocal());
 376     } else {
 377       AbbrevToUse = SimpleGVarAbbrev;
 378     }
 379
 380     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 381     Vals.clear();
 382   }
 383
 384   // Emit the function proto information.
 385   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 386     // FUNCTION:  [type, callingconv, isproto, linkage, alignment, section,
 387     //             visibility]
 388     Vals.push_back(VE.getTypeID(F->getType()));
 389     Vals.push_back(F->getCallingConv());
 390     Vals.push_back(F->isDeclaration());
 391     Vals.push_back(getEncodedLinkage(F));
 392
 393     // Note: we emit the param attr ID number for the function type of this
 394     // function.  In the future, we intend for attrs to be properties of
 395     // functions, instead of on the type.  This is to support this future work.
 396     Vals.push_back(VE.getParamAttrID(F->getFunctionType()->getParamAttrs()));
 397
 398     Vals.push_back(Log2_32(F->getAlignment())+1);
 399     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 400     Vals.push_back(getEncodedVisibility(F));
 401
 402     unsigned AbbrevToUse = 0;
 403     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 404     Vals.clear();
 405   }
 406
 407
 408   // Emit the alias information.
 409   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 410        AI != E; ++AI) {
 411     Vals.push_back(VE.getTypeID(AI->getType()));
 412     Vals.push_back(VE.getValueID(AI->getAliasee()));
 413     Vals.push_back(getEncodedLinkage(AI));
 414     unsigned AbbrevToUse = 0;
 415     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 416     Vals.clear();
 417   }
 418 }
 419
 420
 421 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 422                            const ValueEnumerator &VE,
 423                            BitstreamWriter &Stream, bool isGlobal) {
 424   if (FirstVal == LastVal) return;
 425
 426   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 427
 428   unsigned AggregateAbbrev = 0;
 429   unsigned String8Abbrev = 0;
 430   unsigned CString7Abbrev = 0;
 431   unsigned CString6Abbrev = 0;
 432   // If this is a constant pool for the module, emit module-specific abbrevs.
 433   if (isGlobal) {
 434     // Abbrev for CST_CODE_AGGREGATE.
 435     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 436     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 439     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 440
 441     // Abbrev for CST_CODE_STRING.
 442     Abbv = new BitCodeAbbrev();
 443     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 445     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 446     String8Abbrev = Stream.EmitAbbrev(Abbv);
 447     // Abbrev for CST_CODE_CSTRING.
 448     Abbv = new BitCodeAbbrev();
 449     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 452     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 453     // Abbrev for CST_CODE_CSTRING.
 454     Abbv = new BitCodeAbbrev();
 455     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 458     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 459   }
 460
 461   SmallVector<uint64_t, 64> Record;
 462
 463   const ValueEnumerator::ValueList &Vals = VE.getValues();
 464   const Type *LastTy = 0;
 465   for (unsigned i = FirstVal; i != LastVal; ++i) {
 466     const Value *V = Vals[i].first;
 467     // If we need to switch types, do so now.
 468     if (V->getType() != LastTy) {
 469       LastTy = V->getType();
 470       Record.push_back(VE.getTypeID(LastTy));
 471       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 472                         CONSTANTS_SETTYPE_ABBREV);
 473       Record.clear();
 474     }
 475
 476     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 477       Record.push_back(unsigned(IA->hasSideEffects()));
 478
 479       // Add the asm string.
 480       const std::string &AsmStr = IA->getAsmString();
 481       Record.push_back(AsmStr.size());
 482       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 483         Record.push_back(AsmStr[i]);
 484
 485       // Add the constraint string.
 486       const std::string &ConstraintStr = IA->getConstraintString();
 487       Record.push_back(ConstraintStr.size());
 488       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 489         Record.push_back(ConstraintStr[i]);
 490       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 491       Record.clear();
 492       continue;
 493     }
 494     const Constant *C = cast<Constant>(V);
 495     unsigned Code = -1U;
 496     unsigned AbbrevToUse = 0;
 497     if (C->isNullValue()) {
 498       Code = bitc::CST_CODE_NULL;
 499     } else if (isa<UndefValue>(C)) {
 500       Code = bitc::CST_CODE_UNDEF;
 501     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 502       if (IV->getBitWidth() <= 64) {
 503         int64_t V = IV->getSExtValue();
 504         if (V >= 0)
 505           Record.push_back(V << 1);
 506         else
 507           Record.push_back((-V << 1) | 1);
 508         Code = bitc::CST_CODE_INTEGER;
 509         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 510       } else {                             // Wide integers, > 64 bits in size.
 511         // We have an arbitrary precision integer value to write whose
 512         // bit width is > 64. However, in canonical unsigned integer
 513         // format it is likely that the high bits are going to be zero.
 514         // So, we only write the number of active words.
 515         unsigned NWords = IV->getValue().getActiveWords();
 516         const uint64_t *RawWords = IV->getValue().getRawData();
 517         for (unsigned i = 0; i != NWords; ++i) {
 518           int64_t V = RawWords[i];
 519           if (V >= 0)
 520             Record.push_back(V << 1);
 521           else
 522             Record.push_back((-V << 1) | 1);
 523         }
 524         Code = bitc::CST_CODE_WIDE_INTEGER;
 525       }
 526     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 527       Code = bitc::CST_CODE_FLOAT;
 528       const Type *Ty = CFP->getType();
 529       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 530         Record.push_back(CFP->getValueAPF().convertToAPInt().getZExtValue());
 531       } else if (Ty == Type::X86_FP80Ty) {
 532         // api needed to prevent premature destruction
 533         APInt api = CFP->getValueAPF().convertToAPInt();
 534         const uint64_t *p = api.getRawData();
 535         Record.push_back(p[0]);
 536         Record.push_back((uint16_t)p[1]);
 537       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 538         APInt api = CFP->getValueAPF().convertToAPInt();
 539         const uint64_t *p = api.getRawData();
 540         Record.push_back(p[0]);
 541         Record.push_back(p[1]);
 542       } else {
 543         assert (0 && "Unknown FP type!");
 544       }
 545     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 546       // Emit constant strings specially.
 547       unsigned NumOps = C->getNumOperands();
 548       // If this is a null-terminated string, use the denser CSTRING encoding.
 549       if (C->getOperand(NumOps-1)->isNullValue()) {
 550         Code = bitc::CST_CODE_CSTRING;
 551         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 552       } else {
 553         Code = bitc::CST_CODE_STRING;
 554         AbbrevToUse = String8Abbrev;
 555       }
 556       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 557       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 558       for (unsigned i = 0; i != NumOps; ++i) {
 559         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 560         Record.push_back(V);
 561         isCStr7 &= (V & 128) == 0;
 562         if (isCStrChar6)
 563           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 564       }
 565
 566       if (isCStrChar6)
 567         AbbrevToUse = CString6Abbrev;
 568       else if (isCStr7)
 569         AbbrevToUse = CString7Abbrev;
 570     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 571                isa<ConstantVector>(V)) {
 572       Code = bitc::CST_CODE_AGGREGATE;
 573       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 574         Record.push_back(VE.getValueID(C->getOperand(i)));
 575       AbbrevToUse = AggregateAbbrev;
 576     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 577       switch (CE->getOpcode()) {
 578       default:
 579         if (Instruction::isCast(CE->getOpcode())) {
 580           Code = bitc::CST_CODE_CE_CAST;
 581           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 582           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 583           Record.push_back(VE.getValueID(C->getOperand(0)));
 584           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 585         } else {
 586           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 587           Code = bitc::CST_CODE_CE_BINOP;
 588           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 589           Record.push_back(VE.getValueID(C->getOperand(0)));
 590           Record.push_back(VE.getValueID(C->getOperand(1)));
 591         }
 592         break;
 593       case Instruction::GetElementPtr:
 594         Code = bitc::CST_CODE_CE_GEP;
 595         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 596           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 597           Record.push_back(VE.getValueID(C->getOperand(i)));
 598         }
 599         break;
 600       case Instruction::Select:
 601         Code = bitc::CST_CODE_CE_SELECT;
 602         Record.push_back(VE.getValueID(C->getOperand(0)));
 603         Record.push_back(VE.getValueID(C->getOperand(1)));
 604         Record.push_back(VE.getValueID(C->getOperand(2)));
 605         break;
 606       case Instruction::ExtractElement:
 607         Code = bitc::CST_CODE_CE_EXTRACTELT;
 608         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 609         Record.push_back(VE.getValueID(C->getOperand(0)));
 610         Record.push_back(VE.getValueID(C->getOperand(1)));
 611         break;
 612       case Instruction::InsertElement:
 613         Code = bitc::CST_CODE_CE_INSERTELT;
 614         Record.push_back(VE.getValueID(C->getOperand(0)));
 615         Record.push_back(VE.getValueID(C->getOperand(1)));
 616         Record.push_back(VE.getValueID(C->getOperand(2)));
 617         break;
 618       case Instruction::ShuffleVector:
 619         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 620         Record.push_back(VE.getValueID(C->getOperand(0)));
 621         Record.push_back(VE.getValueID(C->getOperand(1)));
 622         Record.push_back(VE.getValueID(C->getOperand(2)));
 623         break;
 624       case Instruction::ICmp:
 625       case Instruction::FCmp:
 626         Code = bitc::CST_CODE_CE_CMP;
 627         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 628         Record.push_back(VE.getValueID(C->getOperand(0)));
 629         Record.push_back(VE.getValueID(C->getOperand(1)));
 630         Record.push_back(CE->getPredicate());
 631         break;
 632       }
 633     } else {
 634       assert(0 && "Unknown constant!");
 635     }
 636     Stream.EmitRecord(Code, Record, AbbrevToUse);
 637     Record.clear();
 638   }
 639
 640   Stream.ExitBlock();
 641 }
 642
 643 static void WriteModuleConstants(const ValueEnumerator &VE,
 644                                  BitstreamWriter &Stream) {
 645   const ValueEnumerator::ValueList &Vals = VE.getValues();
 646
 647   // Find the first constant to emit, which is the first non-globalvalue value.
 648   // We know globalvalues have been emitted by WriteModuleInfo.
 649   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 650     if (!isa<GlobalValue>(Vals[i].first)) {
 651       WriteConstants(i, Vals.size(), VE, Stream, true);
 652       return;
 653     }
 654   }
 655 }
 656
 657 /// PushValueAndType - The file has to encode both the value and type id for
 658 /// many values, because we need to know what type to create for forward
 659 /// references.  However, most operands are not forward references, so this type
 660 /// field is not needed.
 661 ///
 662 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 663 /// instruction ID, then it is a forward reference, and it also includes the
 664 /// type ID.
 665 static bool PushValueAndType(Value *V, unsigned InstID,
 666                              SmallVector<unsigned, 64> &Vals,
 667                              ValueEnumerator &VE) {
 668   unsigned ValID = VE.getValueID(V);
 669   Vals.push_back(ValID);
 670   if (ValID >= InstID) {
 671     Vals.push_back(VE.getTypeID(V->getType()));
 672     return true;
 673   }
 674   return false;
 675 }
 676
 677 /// WriteInstruction - Emit an instruction to the specified stream.
 678 static void WriteInstruction(const Instruction &I, unsigned InstID,
 679                              ValueEnumerator &VE, BitstreamWriter &Stream,
 680                              SmallVector<unsigned, 64> &Vals) {
 681   unsigned Code = 0;
 682   unsigned AbbrevToUse = 0;
 683   switch (I.getOpcode()) {
 684   default:
 685     if (Instruction::isCast(I.getOpcode())) {
 686       Code = bitc::FUNC_CODE_INST_CAST;
 687       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 688         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 689       Vals.push_back(VE.getTypeID(I.getType()));
 690       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 691     } else {
 692       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 693       Code = bitc::FUNC_CODE_INST_BINOP;
 694       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 695         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 696       Vals.push_back(VE.getValueID(I.getOperand(1)));
 697       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 698     }
 699     break;
 700
 701   case Instruction::GetElementPtr:
 702     Code = bitc::FUNC_CODE_INST_GEP;
 703     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 704       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 705     break;
 706   case Instruction::Select:
 707     Code = bitc::FUNC_CODE_INST_SELECT;
 708     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 709     Vals.push_back(VE.getValueID(I.getOperand(2)));
 710     Vals.push_back(VE.getValueID(I.getOperand(0)));
 711     break;
 712   case Instruction::ExtractElement:
 713     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 714     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 715     Vals.push_back(VE.getValueID(I.getOperand(1)));
 716     break;
 717   case Instruction::InsertElement:
 718     Code = bitc::FUNC_CODE_INST_INSERTELT;
 719     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 720     Vals.push_back(VE.getValueID(I.getOperand(1)));
 721     Vals.push_back(VE.getValueID(I.getOperand(2)));
 722     break;
 723   case Instruction::ShuffleVector:
 724     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 725     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 726     Vals.push_back(VE.getValueID(I.getOperand(1)));
 727     Vals.push_back(VE.getValueID(I.getOperand(2)));
 728     break;
 729   case Instruction::ICmp:
 730   case Instruction::FCmp:
 731     Code = bitc::FUNC_CODE_INST_CMP;
 732     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 733     Vals.push_back(VE.getValueID(I.getOperand(1)));
 734     Vals.push_back(cast<CmpInst>(I).getPredicate());
 735     break;
 736
 737   case Instruction::Ret:
 738     Code = bitc::FUNC_CODE_INST_RET;
 739     if (!I.getNumOperands())
 740       AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 741     else if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 742       AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 743     break;
 744   case Instruction::Br:
 745     Code = bitc::FUNC_CODE_INST_BR;
 746     Vals.push_back(VE.getValueID(I.getOperand(0)));
 747     if (cast<BranchInst>(I).isConditional()) {
 748       Vals.push_back(VE.getValueID(I.getOperand(1)));
 749       Vals.push_back(VE.getValueID(I.getOperand(2)));
 750     }
 751     break;
 752   case Instruction::Switch:
 753     Code = bitc::FUNC_CODE_INST_SWITCH;
 754     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 755     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 756       Vals.push_back(VE.getValueID(I.getOperand(i)));
 757     break;
 758   case Instruction::Invoke: {
 759     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 760     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 761     Code = bitc::FUNC_CODE_INST_INVOKE;
 762
 763     // Note: we emit the param attr ID number for the function type of this
 764     // function.  In the future, we intend for attrs to be properties of
 765     // functions, instead of on the type.  This is to support this future work.
 766     Vals.push_back(VE.getParamAttrID(FTy->getParamAttrs()));
 767
 768     Vals.push_back(cast<InvokeInst>(I).getCallingConv());
 769     Vals.push_back(VE.getValueID(I.getOperand(1)));      // normal dest
 770     Vals.push_back(VE.getValueID(I.getOperand(2)));      // unwind dest
 771     PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
 772
 773     // Emit value #'s for the fixed parameters.
 774     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 775       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 776
 777     // Emit type/value pairs for varargs params.
 778     if (FTy->isVarArg()) {
 779       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 780            i != e; ++i)
 781         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 782     }
 783     break;
 784   }
 785   case Instruction::Unwind:
 786     Code = bitc::FUNC_CODE_INST_UNWIND;
 787     break;
 788   case Instruction::Unreachable:
 789     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 790     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 791     break;
 792
 793   case Instruction::PHI:
 794     Code = bitc::FUNC_CODE_INST_PHI;
 795     Vals.push_back(VE.getTypeID(I.getType()));
 796     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 797       Vals.push_back(VE.getValueID(I.getOperand(i)));
 798     break;
 799
 800   case Instruction::Malloc:
 801     Code = bitc::FUNC_CODE_INST_MALLOC;
 802     Vals.push_back(VE.getTypeID(I.getType()));
 803     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 804     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 805     break;
 806
 807   case Instruction::Free:
 808     Code = bitc::FUNC_CODE_INST_FREE;
 809     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 810     break;
 811
 812   case Instruction::Alloca:
 813     Code = bitc::FUNC_CODE_INST_ALLOCA;
 814     Vals.push_back(VE.getTypeID(I.getType()));
 815     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 816     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 817     break;
 818
 819   case Instruction::Load:
 820     Code = bitc::FUNC_CODE_INST_LOAD;
 821     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 822       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 823
 824     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 825     Vals.push_back(cast<LoadInst>(I).isVolatile());
 826     break;
 827   case Instruction::Store:
 828     Code = bitc::FUNC_CODE_INST_STORE;
 829     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // val.
 830     Vals.push_back(VE.getValueID(I.getOperand(1)));       // ptr.
 831     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 832     Vals.push_back(cast<StoreInst>(I).isVolatile());
 833     break;
 834   case Instruction::Call: {
 835     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 836     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 837
 838     Code = bitc::FUNC_CODE_INST_CALL;
 839
 840     // Note: we emit the param attr ID number for the function type of this
 841     // function.  In the future, we intend for attrs to be properties of
 842     // functions, instead of on the type.  This is to support this future work.
 843     Vals.push_back(VE.getParamAttrID(FTy->getParamAttrs()));
 844
 845     Vals.push_back((cast<CallInst>(I).getCallingConv() << 1) |
 846                    unsigned(cast<CallInst>(I).isTailCall()));
 847     PushValueAndType(I.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 }