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