lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/MDNode.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/TypeSymbolTable.h"
  25 #include "llvm/ValueSymbolTable.h"
  26 #include "llvm/Support/ErrorHandling.h"
  27 #include "llvm/Support/MathExtras.h"
  28 #include "llvm/Support/Streams.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/System/Program.h"
  31 using namespace llvm;
  32
  33 /// These are manifest constants used by the bitcode writer. They do not need to
  34 /// be kept in sync with the reader, but need to be consistent within this file.
  35 enum {
  36   CurVersion = 0,
  37
  38   // VALUE_SYMTAB_BLOCK abbrev id's.
  39   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  40   VST_ENTRY_7_ABBREV,
  41   VST_ENTRY_6_ABBREV,
  42   VST_BBENTRY_6_ABBREV,
  43
  44   // CONSTANTS_BLOCK abbrev id's.
  45   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  46   CONSTANTS_INTEGER_ABBREV,
  47   CONSTANTS_CE_CAST_Abbrev,
  48   CONSTANTS_NULL_Abbrev,
  49
  50   // FUNCTION_BLOCK abbrev id's.
  51   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  52   FUNCTION_INST_BINOP_ABBREV,
  53   FUNCTION_INST_CAST_ABBREV,
  54   FUNCTION_INST_RET_VOID_ABBREV,
  55   FUNCTION_INST_RET_VAL_ABBREV,
  56   FUNCTION_INST_UNREACHABLE_ABBREV
  57 };
  58
  59
  60 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  61   switch (Opcode) {
  62   default: LLVM_UNREACHABLE("Unknown cast instruction!");
  63   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  64   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  65   case Instruction::SExt    : return bitc::CAST_SEXT;
  66   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  67   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  68   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  69   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  70   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  71   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  72   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  73   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  74   case Instruction::BitCast : return bitc::CAST_BITCAST;
  75   }
  76 }
  77
  78 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  79   switch (Opcode) {
  80   default: LLVM_UNREACHABLE("Unknown binary instruction!");
  81   case Instruction::Add:
  82   case Instruction::FAdd: return bitc::BINOP_ADD;
  83   case Instruction::Sub:
  84   case Instruction::FSub: return bitc::BINOP_SUB;
  85   case Instruction::Mul:
  86   case Instruction::FMul: return bitc::BINOP_MUL;
  87   case Instruction::UDiv: return bitc::BINOP_UDIV;
  88   case Instruction::FDiv:
  89   case Instruction::SDiv: return bitc::BINOP_SDIV;
  90   case Instruction::URem: return bitc::BINOP_UREM;
  91   case Instruction::FRem:
  92   case Instruction::SRem: return bitc::BINOP_SREM;
  93   case Instruction::Shl:  return bitc::BINOP_SHL;
  94   case Instruction::LShr: return bitc::BINOP_LSHR;
  95   case Instruction::AShr: return bitc::BINOP_ASHR;
  96   case Instruction::And:  return bitc::BINOP_AND;
  97   case Instruction::Or:   return bitc::BINOP_OR;
  98   case Instruction::Xor:  return bitc::BINOP_XOR;
  99   }
 100 }
 101
 102
 103
 104 static void WriteStringRecord(unsigned Code, const std::string &Str,
 105                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 106   SmallVector<unsigned, 64> Vals;
 107
 108   // Code: [strchar x N]
 109   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 110     Vals.push_back(Str[i]);
 111
 112   // Emit the finished record.
 113   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 114 }
 115
 116 // Emit information about parameter attributes.
 117 static void WriteAttributeTable(const ValueEnumerator &VE,
 118                                 BitstreamWriter &Stream) {
 119   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 120   if (Attrs.empty()) return;
 121
 122   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 123
 124   SmallVector<uint64_t, 64> Record;
 125   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 126     const AttrListPtr &A = Attrs[i];
 127     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 128       const AttributeWithIndex &PAWI = A.getSlot(i);
 129       Record.push_back(PAWI.Index);
 130
 131       // FIXME: remove in LLVM 3.0
 132       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 133       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 134       // 11 bits.
 135       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 136       if (PAWI.Attrs & Attribute::Alignment)
 137         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 138       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 139
 140       Record.push_back(FauxAttr);
 141     }
 142
 143     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 144     Record.clear();
 145   }
 146
 147   Stream.ExitBlock();
 148 }
 149
 150 /// WriteTypeTable - Write out the type table for a module.
 151 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 152   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 153
 154   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 155   SmallVector<uint64_t, 64> TypeVals;
 156
 157   // Abbrev for TYPE_CODE_POINTER.
 158   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 159   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 161                             Log2_32_Ceil(VE.getTypes().size()+1)));
 162   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 163   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 164
 165   // Abbrev for TYPE_CODE_FUNCTION.
 166   Abbv = new BitCodeAbbrev();
 167   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 169   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 172                             Log2_32_Ceil(VE.getTypes().size()+1)));
 173   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 174
 175   // Abbrev for TYPE_CODE_STRUCT.
 176   Abbv = new BitCodeAbbrev();
 177   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 181                             Log2_32_Ceil(VE.getTypes().size()+1)));
 182   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 183
 184   // Abbrev for TYPE_CODE_ARRAY.
 185   Abbv = new BitCodeAbbrev();
 186   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 189                             Log2_32_Ceil(VE.getTypes().size()+1)));
 190   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 191
 192   // Emit an entry count so the reader can reserve space.
 193   TypeVals.push_back(TypeList.size());
 194   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 195   TypeVals.clear();
 196
 197   // Loop over all of the types, emitting each in turn.
 198   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 199     const Type *T = TypeList[i].first;
 200     int AbbrevToUse = 0;
 201     unsigned Code = 0;
 202
 203     switch (T->getTypeID()) {
 204     default: LLVM_UNREACHABLE("Unknown type!");
 205     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 206     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 207     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 208     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 209     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 210     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 211     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 212     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 213     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 214     case Type::IntegerTyID:
 215       // INTEGER: [width]
 216       Code = bitc::TYPE_CODE_INTEGER;
 217       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 218       break;
 219     case Type::PointerTyID: {
 220       const PointerType *PTy = cast<PointerType>(T);
 221       // POINTER: [pointee type, address space]
 222       Code = bitc::TYPE_CODE_POINTER;
 223       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 224       unsigned AddressSpace = PTy->getAddressSpace();
 225       TypeVals.push_back(AddressSpace);
 226       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 227       break;
 228     }
 229     case Type::FunctionTyID: {
 230       const FunctionType *FT = cast<FunctionType>(T);
 231       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 232       Code = bitc::TYPE_CODE_FUNCTION;
 233       TypeVals.push_back(FT->isVarArg());
 234       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 235       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 236       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 237         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 238       AbbrevToUse = FunctionAbbrev;
 239       break;
 240     }
 241     case Type::StructTyID: {
 242       const StructType *ST = cast<StructType>(T);
 243       // STRUCT: [ispacked, eltty x N]
 244       Code = bitc::TYPE_CODE_STRUCT;
 245       TypeVals.push_back(ST->isPacked());
 246       // Output all of the element types.
 247       for (StructType::element_iterator I = ST->element_begin(),
 248            E = ST->element_end(); I != E; ++I)
 249         TypeVals.push_back(VE.getTypeID(*I));
 250       AbbrevToUse = StructAbbrev;
 251       break;
 252     }
 253     case Type::ArrayTyID: {
 254       const ArrayType *AT = cast<ArrayType>(T);
 255       // ARRAY: [numelts, eltty]
 256       Code = bitc::TYPE_CODE_ARRAY;
 257       TypeVals.push_back(AT->getNumElements());
 258       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 259       AbbrevToUse = ArrayAbbrev;
 260       break;
 261     }
 262     case Type::VectorTyID: {
 263       const VectorType *VT = cast<VectorType>(T);
 264       // VECTOR [numelts, eltty]
 265       Code = bitc::TYPE_CODE_VECTOR;
 266       TypeVals.push_back(VT->getNumElements());
 267       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 268       break;
 269     }
 270     }
 271
 272     // Emit the finished record.
 273     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 274     TypeVals.clear();
 275   }
 276
 277   Stream.ExitBlock();
 278 }
 279
 280 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 281   switch (GV->getLinkage()) {
 282   default: LLVM_UNREACHABLE("Invalid linkage!");
 283   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 284   case GlobalValue::ExternalLinkage:     return 0;
 285   case GlobalValue::WeakAnyLinkage:      return 1;
 286   case GlobalValue::AppendingLinkage:    return 2;
 287   case GlobalValue::InternalLinkage:     return 3;
 288   case GlobalValue::LinkOnceAnyLinkage:  return 4;
 289   case GlobalValue::DLLImportLinkage:    return 5;
 290   case GlobalValue::DLLExportLinkage:    return 6;
 291   case GlobalValue::ExternalWeakLinkage: return 7;
 292   case GlobalValue::CommonLinkage:       return 8;
 293   case GlobalValue::PrivateLinkage:      return 9;
 294   case GlobalValue::WeakODRLinkage:      return 10;
 295   case GlobalValue::LinkOnceODRLinkage:  return 11;
 296   case GlobalValue::AvailableExternallyLinkage:  return 12;
 297   }
 298 }
 299
 300 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 301   switch (GV->getVisibility()) {
 302   default: LLVM_UNREACHABLE("Invalid visibility!");
 303   case GlobalValue::DefaultVisibility:   return 0;
 304   case GlobalValue::HiddenVisibility:    return 1;
 305   case GlobalValue::ProtectedVisibility: return 2;
 306   }
 307 }
 308
 309 // Emit top-level description of module, including target triple, inline asm,
 310 // descriptors for global variables, and function prototype info.
 311 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 312                             BitstreamWriter &Stream) {
 313   // Emit the list of dependent libraries for the Module.
 314   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 315     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 316
 317   // Emit various pieces of data attached to a module.
 318   if (!M->getTargetTriple().empty())
 319     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 320                       0/*TODO*/, Stream);
 321   if (!M->getDataLayout().empty())
 322     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 323                       0/*TODO*/, Stream);
 324   if (!M->getModuleInlineAsm().empty())
 325     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 326                       0/*TODO*/, Stream);
 327
 328   // Emit information about sections and GC, computing how many there are. Also
 329   // compute the maximum alignment value.
 330   std::map<std::string, unsigned> SectionMap;
 331   std::map<std::string, unsigned> GCMap;
 332   unsigned MaxAlignment = 0;
 333   unsigned MaxGlobalType = 0;
 334   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 335        GV != E; ++GV) {
 336     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 337     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 338
 339     if (!GV->hasSection()) continue;
 340     // Give section names unique ID's.
 341     unsigned &Entry = SectionMap[GV->getSection()];
 342     if (Entry != 0) continue;
 343     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 344                       0/*TODO*/, Stream);
 345     Entry = SectionMap.size();
 346   }
 347   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 348     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 349     if (F->hasSection()) {
 350       // Give section names unique ID's.
 351       unsigned &Entry = SectionMap[F->getSection()];
 352       if (!Entry) {
 353         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 354                           0/*TODO*/, Stream);
 355         Entry = SectionMap.size();
 356       }
 357     }
 358     if (F->hasGC()) {
 359       // Same for GC names.
 360       unsigned &Entry = GCMap[F->getGC()];
 361       if (!Entry) {
 362         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 363                           0/*TODO*/, Stream);
 364         Entry = GCMap.size();
 365       }
 366     }
 367   }
 368
 369   // Emit abbrev for globals, now that we know # sections and max alignment.
 370   unsigned SimpleGVarAbbrev = 0;
 371   if (!M->global_empty()) {
 372     // Add an abbrev for common globals with no visibility or thread localness.
 373     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 374     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 376                               Log2_32_Ceil(MaxGlobalType+1)));
 377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 380     if (MaxAlignment == 0)                                      // Alignment.
 381       Abbv->Add(BitCodeAbbrevOp(0));
 382     else {
 383       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 384       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 385                                Log2_32_Ceil(MaxEncAlignment+1)));
 386     }
 387     if (SectionMap.empty())                                    // Section.
 388       Abbv->Add(BitCodeAbbrevOp(0));
 389     else
 390       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 391                                Log2_32_Ceil(SectionMap.size()+1)));
 392     // Don't bother emitting vis + thread local.
 393     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 394   }
 395
 396   // Emit the global variable information.
 397   SmallVector<unsigned, 64> Vals;
 398   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 399        GV != E; ++GV) {
 400     unsigned AbbrevToUse = 0;
 401
 402     // GLOBALVAR: [type, isconst, initid,
 403     //             linkage, alignment, section, visibility, threadlocal]
 404     Vals.push_back(VE.getTypeID(GV->getType()));
 405     Vals.push_back(GV->isConstant());
 406     Vals.push_back(GV->isDeclaration() ? 0 :
 407                    (VE.getValueID(GV->getInitializer()) + 1));
 408     Vals.push_back(getEncodedLinkage(GV));
 409     Vals.push_back(Log2_32(GV->getAlignment())+1);
 410     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 411     if (GV->isThreadLocal() ||
 412         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 413       Vals.push_back(getEncodedVisibility(GV));
 414       Vals.push_back(GV->isThreadLocal());
 415     } else {
 416       AbbrevToUse = SimpleGVarAbbrev;
 417     }
 418
 419     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 420     Vals.clear();
 421   }
 422
 423   // Emit the function proto information.
 424   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 425     // FUNCTION:  [type, callingconv, isproto, paramattr,
 426     //             linkage, alignment, section, visibility, gc]
 427     Vals.push_back(VE.getTypeID(F->getType()));
 428     Vals.push_back(F->getCallingConv());
 429     Vals.push_back(F->isDeclaration());
 430     Vals.push_back(getEncodedLinkage(F));
 431     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 432     Vals.push_back(Log2_32(F->getAlignment())+1);
 433     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 434     Vals.push_back(getEncodedVisibility(F));
 435     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 436
 437     unsigned AbbrevToUse = 0;
 438     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 439     Vals.clear();
 440   }
 441
 442
 443   // Emit the alias information.
 444   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 445        AI != E; ++AI) {
 446     Vals.push_back(VE.getTypeID(AI->getType()));
 447     Vals.push_back(VE.getValueID(AI->getAliasee()));
 448     Vals.push_back(getEncodedLinkage(AI));
 449     Vals.push_back(getEncodedVisibility(AI));
 450     unsigned AbbrevToUse = 0;
 451     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 452     Vals.clear();
 453   }
 454 }
 455
 456
 457 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 458                            const ValueEnumerator &VE,
 459                            BitstreamWriter &Stream, bool isGlobal) {
 460   if (FirstVal == LastVal) return;
 461
 462   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 463
 464   unsigned AggregateAbbrev = 0;
 465   unsigned String8Abbrev = 0;
 466   unsigned CString7Abbrev = 0;
 467   unsigned CString6Abbrev = 0;
 468   unsigned MDString8Abbrev = 0;
 469   unsigned MDString6Abbrev = 0;
 470   // If this is a constant pool for the module, emit module-specific abbrevs.
 471   if (isGlobal) {
 472     // Abbrev for CST_CODE_AGGREGATE.
 473     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 474     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 477     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 478
 479     // Abbrev for CST_CODE_STRING.
 480     Abbv = new BitCodeAbbrev();
 481     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 484     String8Abbrev = Stream.EmitAbbrev(Abbv);
 485     // Abbrev for CST_CODE_CSTRING.
 486     Abbv = new BitCodeAbbrev();
 487     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 490     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 491     // Abbrev for CST_CODE_CSTRING.
 492     Abbv = new BitCodeAbbrev();
 493     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 496     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 497
 498     // Abbrev for CST_CODE_MDSTRING.
 499     Abbv = new BitCodeAbbrev();
 500     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 503     MDString8Abbrev = Stream.EmitAbbrev(Abbv);
 504     // Abbrev for CST_CODE_MDSTRING.
 505     Abbv = new BitCodeAbbrev();
 506     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 509     MDString6Abbrev = Stream.EmitAbbrev(Abbv);
 510   }
 511
 512   SmallVector<uint64_t, 64> Record;
 513
 514   const ValueEnumerator::ValueList &Vals = VE.getValues();
 515   const Type *LastTy = 0;
 516   for (unsigned i = FirstVal; i != LastVal; ++i) {
 517     const Value *V = Vals[i].first;
 518     // If we need to switch types, do so now.
 519     if (V->getType() != LastTy) {
 520       LastTy = V->getType();
 521       Record.push_back(VE.getTypeID(LastTy));
 522       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 523                         CONSTANTS_SETTYPE_ABBREV);
 524       Record.clear();
 525     }
 526
 527     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 528       Record.push_back(unsigned(IA->hasSideEffects()));
 529
 530       // Add the asm string.
 531       const std::string &AsmStr = IA->getAsmString();
 532       Record.push_back(AsmStr.size());
 533       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 534         Record.push_back(AsmStr[i]);
 535
 536       // Add the constraint string.
 537       const std::string &ConstraintStr = IA->getConstraintString();
 538       Record.push_back(ConstraintStr.size());
 539       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 540         Record.push_back(ConstraintStr[i]);
 541       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 542       Record.clear();
 543       continue;
 544     }
 545     const Constant *C = cast<Constant>(V);
 546     unsigned Code = -1U;
 547     unsigned AbbrevToUse = 0;
 548     if (C->isNullValue()) {
 549       Code = bitc::CST_CODE_NULL;
 550     } else if (isa<UndefValue>(C)) {
 551       Code = bitc::CST_CODE_UNDEF;
 552     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 553       if (IV->getBitWidth() <= 64) {
 554         int64_t V = IV->getSExtValue();
 555         if (V >= 0)
 556           Record.push_back(V << 1);
 557         else
 558           Record.push_back((-V << 1) | 1);
 559         Code = bitc::CST_CODE_INTEGER;
 560         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 561       } else {                             // Wide integers, > 64 bits in size.
 562         // We have an arbitrary precision integer value to write whose
 563         // bit width is > 64. However, in canonical unsigned integer
 564         // format it is likely that the high bits are going to be zero.
 565         // So, we only write the number of active words.
 566         unsigned NWords = IV->getValue().getActiveWords();
 567         const uint64_t *RawWords = IV->getValue().getRawData();
 568         for (unsigned i = 0; i != NWords; ++i) {
 569           int64_t V = RawWords[i];
 570           if (V >= 0)
 571             Record.push_back(V << 1);
 572           else
 573             Record.push_back((-V << 1) | 1);
 574         }
 575         Code = bitc::CST_CODE_WIDE_INTEGER;
 576       }
 577     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 578       Code = bitc::CST_CODE_FLOAT;
 579       const Type *Ty = CFP->getType();
 580       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 581         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 582       } else if (Ty == Type::X86_FP80Ty) {
 583         // api needed to prevent premature destruction
 584         // bits are not in the same order as a normal i80 APInt, compensate.
 585         APInt api = CFP->getValueAPF().bitcastToAPInt();
 586         const uint64_t *p = api.getRawData();
 587         Record.push_back((p[1] << 48) | (p[0] >> 16));
 588         Record.push_back(p[0] & 0xffffLL);
 589       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 590         APInt api = CFP->getValueAPF().bitcastToAPInt();
 591         const uint64_t *p = api.getRawData();
 592         Record.push_back(p[0]);
 593         Record.push_back(p[1]);
 594       } else {
 595         assert (0 && "Unknown FP type!");
 596       }
 597     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 598       // Emit constant strings specially.
 599       unsigned NumOps = C->getNumOperands();
 600       // If this is a null-terminated string, use the denser CSTRING encoding.
 601       if (C->getOperand(NumOps-1)->isNullValue()) {
 602         Code = bitc::CST_CODE_CSTRING;
 603         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 604       } else {
 605         Code = bitc::CST_CODE_STRING;
 606         AbbrevToUse = String8Abbrev;
 607       }
 608       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 609       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 610       for (unsigned i = 0; i != NumOps; ++i) {
 611         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 612         Record.push_back(V);
 613         isCStr7 &= (V & 128) == 0;
 614         if (isCStrChar6)
 615           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 616       }
 617
 618       if (isCStrChar6)
 619         AbbrevToUse = CString6Abbrev;
 620       else if (isCStr7)
 621         AbbrevToUse = CString7Abbrev;
 622     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 623                isa<ConstantVector>(V)) {
 624       Code = bitc::CST_CODE_AGGREGATE;
 625       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 626         Record.push_back(VE.getValueID(C->getOperand(i)));
 627       AbbrevToUse = AggregateAbbrev;
 628     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 629       switch (CE->getOpcode()) {
 630       default:
 631         if (Instruction::isCast(CE->getOpcode())) {
 632           Code = bitc::CST_CODE_CE_CAST;
 633           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 634           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 635           Record.push_back(VE.getValueID(C->getOperand(0)));
 636           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 637         } else {
 638           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 639           Code = bitc::CST_CODE_CE_BINOP;
 640           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 641           Record.push_back(VE.getValueID(C->getOperand(0)));
 642           Record.push_back(VE.getValueID(C->getOperand(1)));
 643         }
 644         break;
 645       case Instruction::GetElementPtr:
 646         Code = bitc::CST_CODE_CE_GEP;
 647         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 648           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 649           Record.push_back(VE.getValueID(C->getOperand(i)));
 650         }
 651         break;
 652       case Instruction::Select:
 653         Code = bitc::CST_CODE_CE_SELECT;
 654         Record.push_back(VE.getValueID(C->getOperand(0)));
 655         Record.push_back(VE.getValueID(C->getOperand(1)));
 656         Record.push_back(VE.getValueID(C->getOperand(2)));
 657         break;
 658       case Instruction::ExtractElement:
 659         Code = bitc::CST_CODE_CE_EXTRACTELT;
 660         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 661         Record.push_back(VE.getValueID(C->getOperand(0)));
 662         Record.push_back(VE.getValueID(C->getOperand(1)));
 663         break;
 664       case Instruction::InsertElement:
 665         Code = bitc::CST_CODE_CE_INSERTELT;
 666         Record.push_back(VE.getValueID(C->getOperand(0)));
 667         Record.push_back(VE.getValueID(C->getOperand(1)));
 668         Record.push_back(VE.getValueID(C->getOperand(2)));
 669         break;
 670       case Instruction::ShuffleVector:
 671         // If the return type and argument types are the same, this is a
 672         // standard shufflevector instruction.  If the types are different,
 673         // then the shuffle is widening or truncating the input vectors, and
 674         // the argument type must also be encoded.
 675         if (C->getType() == C->getOperand(0)->getType()) {
 676           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 677         } else {
 678           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 679           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 680         }
 681         Record.push_back(VE.getValueID(C->getOperand(0)));
 682         Record.push_back(VE.getValueID(C->getOperand(1)));
 683         Record.push_back(VE.getValueID(C->getOperand(2)));
 684         break;
 685       case Instruction::ICmp:
 686       case Instruction::FCmp:
 687         Code = bitc::CST_CODE_CE_CMP;
 688         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 689         Record.push_back(VE.getValueID(C->getOperand(0)));
 690         Record.push_back(VE.getValueID(C->getOperand(1)));
 691         Record.push_back(CE->getPredicate());
 692         break;
 693       }
 694     } else if (const MDString *S = dyn_cast<MDString>(C)) {
 695       Code = bitc::CST_CODE_MDSTRING;
 696       AbbrevToUse = MDString6Abbrev;
 697       for (unsigned i = 0, e = S->size(); i != e; ++i) {
 698         char V = S->begin()[i];
 699         Record.push_back(V);
 700
 701         if (!BitCodeAbbrevOp::isChar6(V))
 702           AbbrevToUse = MDString8Abbrev;
 703       }
 704     } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
 705       Code = bitc::CST_CODE_MDNODE;
 706       for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 707         if (N->getElement(i)) {
 708           Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 709           Record.push_back(VE.getValueID(N->getElement(i)));
 710         } else {
 711           Record.push_back(VE.getTypeID(Type::VoidTy));
 712           Record.push_back(0);
 713         }
 714       }
 715     } else {
 716       LLVM_UNREACHABLE("Unknown constant!");
 717     }
 718     Stream.EmitRecord(Code, Record, AbbrevToUse);
 719     Record.clear();
 720   }
 721
 722   Stream.ExitBlock();
 723 }
 724
 725 static void WriteModuleConstants(const ValueEnumerator &VE,
 726                                  BitstreamWriter &Stream) {
 727   const ValueEnumerator::ValueList &Vals = VE.getValues();
 728
 729   // Find the first constant to emit, which is the first non-globalvalue value.
 730   // We know globalvalues have been emitted by WriteModuleInfo.
 731   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 732     if (!isa<GlobalValue>(Vals[i].first)) {
 733       WriteConstants(i, Vals.size(), VE, Stream, true);
 734       return;
 735     }
 736   }
 737 }
 738
 739 /// PushValueAndType - The file has to encode both the value and type id for
 740 /// many values, because we need to know what type to create for forward
 741 /// references.  However, most operands are not forward references, so this type
 742 /// field is not needed.
 743 ///
 744 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 745 /// instruction ID, then it is a forward reference, and it also includes the
 746 /// type ID.
 747 static bool PushValueAndType(const Value *V, unsigned InstID,
 748                              SmallVector<unsigned, 64> &Vals,
 749                              ValueEnumerator &VE) {
 750   unsigned ValID = VE.getValueID(V);
 751   Vals.push_back(ValID);
 752   if (ValID >= InstID) {
 753     Vals.push_back(VE.getTypeID(V->getType()));
 754     return true;
 755   }
 756   return false;
 757 }
 758
 759 /// WriteInstruction - Emit an instruction to the specified stream.
 760 static void WriteInstruction(const Instruction &I, unsigned InstID,
 761                              ValueEnumerator &VE, BitstreamWriter &Stream,
 762                              SmallVector<unsigned, 64> &Vals) {
 763   unsigned Code = 0;
 764   unsigned AbbrevToUse = 0;
 765   switch (I.getOpcode()) {
 766   default:
 767     if (Instruction::isCast(I.getOpcode())) {
 768       Code = bitc::FUNC_CODE_INST_CAST;
 769       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 770         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 771       Vals.push_back(VE.getTypeID(I.getType()));
 772       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 773     } else {
 774       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 775       Code = bitc::FUNC_CODE_INST_BINOP;
 776       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 777         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 778       Vals.push_back(VE.getValueID(I.getOperand(1)));
 779       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 780     }
 781     break;
 782
 783   case Instruction::GetElementPtr:
 784     Code = bitc::FUNC_CODE_INST_GEP;
 785     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 786       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 787     break;
 788   case Instruction::ExtractValue: {
 789     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 790     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 791     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 792     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 793       Vals.push_back(*i);
 794     break;
 795   }
 796   case Instruction::InsertValue: {
 797     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 798     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 799     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 800     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 801     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 802       Vals.push_back(*i);
 803     break;
 804   }
 805   case Instruction::Select:
 806     Code = bitc::FUNC_CODE_INST_VSELECT;
 807     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 808     Vals.push_back(VE.getValueID(I.getOperand(2)));
 809     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 810     break;
 811   case Instruction::ExtractElement:
 812     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 813     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 814     Vals.push_back(VE.getValueID(I.getOperand(1)));
 815     break;
 816   case Instruction::InsertElement:
 817     Code = bitc::FUNC_CODE_INST_INSERTELT;
 818     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 819     Vals.push_back(VE.getValueID(I.getOperand(1)));
 820     Vals.push_back(VE.getValueID(I.getOperand(2)));
 821     break;
 822   case Instruction::ShuffleVector:
 823     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 824     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 825     Vals.push_back(VE.getValueID(I.getOperand(1)));
 826     Vals.push_back(VE.getValueID(I.getOperand(2)));
 827     break;
 828   case Instruction::ICmp:
 829   case Instruction::FCmp:
 830     // compare returning Int1Ty or vector of Int1Ty
 831     Code = bitc::FUNC_CODE_INST_CMP2;
 832     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 833     Vals.push_back(VE.getValueID(I.getOperand(1)));
 834     Vals.push_back(cast<CmpInst>(I).getPredicate());
 835     break;
 836
 837   case Instruction::Ret:
 838     {
 839       Code = bitc::FUNC_CODE_INST_RET;
 840       unsigned NumOperands = I.getNumOperands();
 841       if (NumOperands == 0)
 842         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 843       else if (NumOperands == 1) {
 844         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 845           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 846       } else {
 847         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 848           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 849       }
 850     }
 851     break;
 852   case Instruction::Br:
 853     {
 854       Code = bitc::FUNC_CODE_INST_BR;
 855       BranchInst &II(cast<BranchInst>(I));
 856       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 857       if (II.isConditional()) {
 858         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 859         Vals.push_back(VE.getValueID(II.getCondition()));
 860       }
 861     }
 862     break;
 863   case Instruction::Switch:
 864     Code = bitc::FUNC_CODE_INST_SWITCH;
 865     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 866     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 867       Vals.push_back(VE.getValueID(I.getOperand(i)));
 868     break;
 869   case Instruction::Invoke: {
 870     const InvokeInst *II = cast<InvokeInst>(&I);
 871     const Value *Callee(II->getCalledValue());
 872     const PointerType *PTy = cast<PointerType>(Callee->getType());
 873     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 874     Code = bitc::FUNC_CODE_INST_INVOKE;
 875
 876     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 877     Vals.push_back(II->getCallingConv());
 878     Vals.push_back(VE.getValueID(II->getNormalDest()));
 879     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 880     PushValueAndType(Callee, InstID, Vals, VE);
 881
 882     // Emit value #'s for the fixed parameters.
 883     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 884       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 885
 886     // Emit type/value pairs for varargs params.
 887     if (FTy->isVarArg()) {
 888       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 889            i != e; ++i)
 890         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 891     }
 892     break;
 893   }
 894   case Instruction::Unwind:
 895     Code = bitc::FUNC_CODE_INST_UNWIND;
 896     break;
 897   case Instruction::Unreachable:
 898     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 899     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 900     break;
 901
 902   case Instruction::PHI:
 903     Code = bitc::FUNC_CODE_INST_PHI;
 904     Vals.push_back(VE.getTypeID(I.getType()));
 905     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 906       Vals.push_back(VE.getValueID(I.getOperand(i)));
 907     break;
 908
 909   case Instruction::Malloc:
 910     Code = bitc::FUNC_CODE_INST_MALLOC;
 911     Vals.push_back(VE.getTypeID(I.getType()));
 912     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 913     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 914     break;
 915
 916   case Instruction::Free:
 917     Code = bitc::FUNC_CODE_INST_FREE;
 918     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 919     break;
 920
 921   case Instruction::Alloca:
 922     Code = bitc::FUNC_CODE_INST_ALLOCA;
 923     Vals.push_back(VE.getTypeID(I.getType()));
 924     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 925     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 926     break;
 927
 928   case Instruction::Load:
 929     Code = bitc::FUNC_CODE_INST_LOAD;
 930     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 931       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 932
 933     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 934     Vals.push_back(cast<LoadInst>(I).isVolatile());
 935     break;
 936   case Instruction::Store:
 937     Code = bitc::FUNC_CODE_INST_STORE2;
 938     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 939     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 940     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 941     Vals.push_back(cast<StoreInst>(I).isVolatile());
 942     break;
 943   case Instruction::Call: {
 944     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 945     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 946
 947     Code = bitc::FUNC_CODE_INST_CALL;
 948
 949     const CallInst *CI = cast<CallInst>(&I);
 950     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 951     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 952     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 953
 954     // Emit value #'s for the fixed parameters.
 955     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 956       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 957
 958     // Emit type/value pairs for varargs params.
 959     if (FTy->isVarArg()) {
 960       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 961       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 962            i != e; ++i)
 963         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 964     }
 965     break;
 966   }
 967   case Instruction::VAArg:
 968     Code = bitc::FUNC_CODE_INST_VAARG;
 969     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 970     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 971     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 972     break;
 973   }
 974
 975   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 976   Vals.clear();
 977 }
 978
 979 // Emit names for globals/functions etc.
 980 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 981                                   const ValueEnumerator &VE,
 982                                   BitstreamWriter &Stream) {
 983   if (VST.empty()) return;
 984   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 985
 986   // FIXME: Set up the abbrev, we know how many values there are!
 987   // FIXME: We know if the type names can use 7-bit ascii.
 988   SmallVector<unsigned, 64> NameVals;
 989
 990   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 991        SI != SE; ++SI) {
 992
 993     const ValueName &Name = *SI;
 994
 995     // Figure out the encoding to use for the name.
 996     bool is7Bit = true;
 997     bool isChar6 = true;
 998     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 999          C != E; ++C) {
1000       if (isChar6)
1001         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1002       if ((unsigned char)*C & 128) {
1003         is7Bit = false;
1004         break;  // don't bother scanning the rest.
1005       }
1006     }
1007
1008     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1009
1010     // VST_ENTRY:   [valueid, namechar x N]
1011     // VST_BBENTRY: [bbid, namechar x N]
1012     unsigned Code;
1013     if (isa<BasicBlock>(SI->getValue())) {
1014       Code = bitc::VST_CODE_BBENTRY;
1015       if (isChar6)
1016         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1017     } else {
1018       Code = bitc::VST_CODE_ENTRY;
1019       if (isChar6)
1020         AbbrevToUse = VST_ENTRY_6_ABBREV;
1021       else if (is7Bit)
1022         AbbrevToUse = VST_ENTRY_7_ABBREV;
1023     }
1024
1025     NameVals.push_back(VE.getValueID(SI->getValue()));
1026     for (const char *P = Name.getKeyData(),
1027          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1028       NameVals.push_back((unsigned char)*P);
1029
1030     // Emit the finished record.
1031     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1032     NameVals.clear();
1033   }
1034   Stream.ExitBlock();
1035 }
1036
1037 /// WriteFunction - Emit a function body to the module stream.
1038 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1039                           BitstreamWriter &Stream) {
1040   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1041   VE.incorporateFunction(F);
1042
1043   SmallVector<unsigned, 64> Vals;
1044
1045   // Emit the number of basic blocks, so the reader can create them ahead of
1046   // time.
1047   Vals.push_back(VE.getBasicBlocks().size());
1048   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1049   Vals.clear();
1050
1051   // If there are function-local constants, emit them now.
1052   unsigned CstStart, CstEnd;
1053   VE.getFunctionConstantRange(CstStart, CstEnd);
1054   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1055
1056   // Keep a running idea of what the instruction ID is.
1057   unsigned InstID = CstEnd;
1058
1059   // Finally, emit all the instructions, in order.
1060   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1061     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1062          I != E; ++I) {
1063       WriteInstruction(*I, InstID, VE, Stream, Vals);
1064       if (I->getType() != Type::VoidTy)
1065         ++InstID;
1066     }
1067
1068   // Emit names for all the instructions etc.
1069   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1070
1071   VE.purgeFunction();
1072   Stream.ExitBlock();
1073 }
1074
1075 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1076 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1077                                  const ValueEnumerator &VE,
1078                                  BitstreamWriter &Stream) {
1079   if (TST.empty()) return;
1080
1081   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1082
1083   // 7-bit fixed width VST_CODE_ENTRY strings.
1084   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1085   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1087                             Log2_32_Ceil(VE.getTypes().size()+1)));
1088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1090   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1091
1092   SmallVector<unsigned, 64> NameVals;
1093
1094   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1095        TI != TE; ++TI) {
1096     // TST_ENTRY: [typeid, namechar x N]
1097     NameVals.push_back(VE.getTypeID(TI->second));
1098
1099     const std::string &Str = TI->first;
1100     bool is7Bit = true;
1101     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1102       NameVals.push_back((unsigned char)Str[i]);
1103       if (Str[i] & 128)
1104         is7Bit = false;
1105     }
1106
1107     // Emit the finished record.
1108     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1109     NameVals.clear();
1110   }
1111
1112   Stream.ExitBlock();
1113 }
1114
1115 // Emit blockinfo, which defines the standard abbreviations etc.
1116 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1117   // We only want to emit block info records for blocks that have multiple
1118   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1119   // blocks can defined their abbrevs inline.
1120   Stream.EnterBlockInfoBlock(2);
1121
1122   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1123     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1127     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1128     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1129                                    Abbv) != VST_ENTRY_8_ABBREV)
1130       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1131   }
1132
1133   { // 7-bit fixed width VST_ENTRY strings.
1134     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1135     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1138     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1139     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1140                                    Abbv) != VST_ENTRY_7_ABBREV)
1141       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1142   }
1143   { // 6-bit char6 VST_ENTRY strings.
1144     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1145     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1149     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1150                                    Abbv) != VST_ENTRY_6_ABBREV)
1151       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1152   }
1153   { // 6-bit char6 VST_BBENTRY strings.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1159     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1160                                    Abbv) != VST_BBENTRY_6_ABBREV)
1161       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1162   }
1163
1164
1165
1166   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1167     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1168     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1170                               Log2_32_Ceil(VE.getTypes().size()+1)));
1171     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1172                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1173       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1174   }
1175
1176   { // INTEGER abbrev for CONSTANTS_BLOCK.
1177     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1178     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1179     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1180     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1181                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1182       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1183   }
1184
1185   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1186     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1187     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1190                               Log2_32_Ceil(VE.getTypes().size()+1)));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1192
1193     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1194                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1195       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1196   }
1197   { // NULL abbrev for CONSTANTS_BLOCK.
1198     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1199     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1200     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1201                                    Abbv) != CONSTANTS_NULL_Abbrev)
1202       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1203   }
1204
1205   // FIXME: This should only use space for first class types!
1206
1207   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1208     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1209     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1212     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1213     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1214                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1215       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1216   }
1217   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1218     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1219     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1222     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1223     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1224                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1225       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1226   }
1227   { // INST_CAST abbrev for FUNCTION_BLOCK.
1228     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1229     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1230     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1231     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1232                               Log2_32_Ceil(VE.getTypes().size()+1)));
1233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1234     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1235                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1236       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1237   }
1238
1239   { // INST_RET abbrev for FUNCTION_BLOCK.
1240     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1241     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1242     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1243                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1244       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1245   }
1246   { // INST_RET abbrev for FUNCTION_BLOCK.
1247     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1248     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1250     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1251                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1252       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1253   }
1254   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1255     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1256     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1257     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1258                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1259       LLVM_UNREACHABLE("Unexpected abbrev ordering!");
1260   }
1261
1262   Stream.ExitBlock();
1263 }
1264
1265
1266 /// WriteModule - Emit the specified module to the bitstream.
1267 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1268   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1269
1270   // Emit the version number if it is non-zero.
1271   if (CurVersion) {
1272     SmallVector<unsigned, 1> Vals;
1273     Vals.push_back(CurVersion);
1274     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1275   }
1276
1277   // Analyze the module, enumerating globals, functions, etc.
1278   ValueEnumerator VE(M);
1279
1280   // Emit blockinfo, which defines the standard abbreviations etc.
1281   WriteBlockInfo(VE, Stream);
1282
1283   // Emit information about parameter attributes.
1284   WriteAttributeTable(VE, Stream);
1285
1286   // Emit information describing all of the types in the module.
1287   WriteTypeTable(VE, Stream);
1288
1289   // Emit top-level description of module, including target triple, inline asm,
1290   // descriptors for global variables, and function prototype info.
1291   WriteModuleInfo(M, VE, Stream);
1292
1293   // Emit constants.
1294   WriteModuleConstants(VE, Stream);
1295
1296   // Emit function bodies.
1297   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1298     if (!I->isDeclaration())
1299       WriteFunction(*I, VE, Stream);
1300
1301   // Emit the type symbol table information.
1302   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1303
1304   // Emit names for globals/functions etc.
1305   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1306
1307   Stream.ExitBlock();
1308 }
1309
1310 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1311 /// header and trailer to make it compatible with the system archiver.  To do
1312 /// this we emit the following header, and then emit a trailer that pads the
1313 /// file out to be a multiple of 16 bytes.
1314 ///
1315 /// struct bc_header {
1316 ///   uint32_t Magic;         // 0x0B17C0DE
1317 ///   uint32_t Version;       // Version, currently always 0.
1318 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1319 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1320 ///   uint32_t CPUType;       // CPU specifier.
1321 ///   ... potentially more later ...
1322 /// };
1323 enum {
1324   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1325   DarwinBCHeaderSize = 5*4
1326 };
1327
1328 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1329                                const std::string &TT) {
1330   unsigned CPUType = ~0U;
1331
1332   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1333   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1334   // specific constants here because they are implicitly part of the Darwin ABI.
1335   enum {
1336     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1337     DARWIN_CPU_TYPE_X86        = 7,
1338     DARWIN_CPU_TYPE_POWERPC    = 18
1339   };
1340
1341   if (TT.find("x86_64-") == 0)
1342     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1343   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1344            TT[4] == '-' && TT[1] - '3' < 6)
1345     CPUType = DARWIN_CPU_TYPE_X86;
1346   else if (TT.find("powerpc-") == 0)
1347     CPUType = DARWIN_CPU_TYPE_POWERPC;
1348   else if (TT.find("powerpc64-") == 0)
1349     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1350
1351   // Traditional Bitcode starts after header.
1352   unsigned BCOffset = DarwinBCHeaderSize;
1353
1354   Stream.Emit(0x0B17C0DE, 32);
1355   Stream.Emit(0         , 32);  // Version.
1356   Stream.Emit(BCOffset  , 32);
1357   Stream.Emit(0         , 32);  // Filled in later.
1358   Stream.Emit(CPUType   , 32);
1359 }
1360
1361 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1362 /// finalize the header.
1363 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1364   // Update the size field in the header.
1365   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1366
1367   // If the file is not a multiple of 16 bytes, insert dummy padding.
1368   while (BufferSize & 15) {
1369     Stream.Emit(0, 8);
1370     ++BufferSize;
1371   }
1372 }
1373
1374
1375 /// WriteBitcodeToFile - Write the specified module to the specified output
1376 /// stream.
1377 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1378   raw_os_ostream RawOut(Out);
1379   // If writing to stdout, set binary mode.
1380   if (llvm::cout == Out)
1381     sys::Program::ChangeStdoutToBinary();
1382   WriteBitcodeToFile(M, RawOut);
1383 }
1384
1385 /// WriteBitcodeToFile - Write the specified module to the specified output
1386 /// stream.
1387 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1388   std::vector<unsigned char> Buffer;
1389   BitstreamWriter Stream(Buffer);
1390
1391   Buffer.reserve(256*1024);
1392
1393   WriteBitcodeToStream( M, Stream );
1394
1395   // If writing to stdout, set binary mode.
1396   if (&llvm::outs() == &Out)
1397     sys::Program::ChangeStdoutToBinary();
1398
1399   // Write the generated bitstream to "Out".
1400   Out.write((char*)&Buffer.front(), Buffer.size());
1401
1402   // Make sure it hits disk now.
1403   Out.flush();
1404 }
1405
1406 /// WriteBitcodeToStream - Write the specified module to the specified output
1407 /// stream.
1408 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1409   // If this is darwin, emit a file header and trailer if needed.
1410   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1411   if (isDarwin)
1412     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1413
1414   // Emit the file header.
1415   Stream.Emit((unsigned)'B', 8);
1416   Stream.Emit((unsigned)'C', 8);
1417   Stream.Emit(0x0, 4);
1418   Stream.Emit(0xC, 4);
1419   Stream.Emit(0xE, 4);
1420   Stream.Emit(0xD, 4);
1421
1422   // Emit the module.
1423   WriteModule(M, Stream);
1424
1425   if (isDarwin)
1426     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1427 }