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   case GlobalValue::LinkerPrivateLinkage:       return 13;
 298   }
 299 }
 300
 301 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 302   switch (GV->getVisibility()) {
 303   default: llvm_unreachable("Invalid visibility!");
 304   case GlobalValue::DefaultVisibility:   return 0;
 305   case GlobalValue::HiddenVisibility:    return 1;
 306   case GlobalValue::ProtectedVisibility: return 2;
 307   }
 308 }
 309
 310 // Emit top-level description of module, including target triple, inline asm,
 311 // descriptors for global variables, and function prototype info.
 312 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 313                             BitstreamWriter &Stream) {
 314   // Emit the list of dependent libraries for the Module.
 315   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 316     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 317
 318   // Emit various pieces of data attached to a module.
 319   if (!M->getTargetTriple().empty())
 320     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 321                       0/*TODO*/, Stream);
 322   if (!M->getDataLayout().empty())
 323     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 324                       0/*TODO*/, Stream);
 325   if (!M->getModuleInlineAsm().empty())
 326     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 327                       0/*TODO*/, Stream);
 328
 329   // Emit information about sections and GC, computing how many there are. Also
 330   // compute the maximum alignment value.
 331   std::map<std::string, unsigned> SectionMap;
 332   std::map<std::string, unsigned> GCMap;
 333   unsigned MaxAlignment = 0;
 334   unsigned MaxGlobalType = 0;
 335   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 336        GV != E; ++GV) {
 337     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 338     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 339
 340     if (!GV->hasSection()) continue;
 341     // Give section names unique ID's.
 342     unsigned &Entry = SectionMap[GV->getSection()];
 343     if (Entry != 0) continue;
 344     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 345                       0/*TODO*/, Stream);
 346     Entry = SectionMap.size();
 347   }
 348   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 349     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 350     if (F->hasSection()) {
 351       // Give section names unique ID's.
 352       unsigned &Entry = SectionMap[F->getSection()];
 353       if (!Entry) {
 354         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 355                           0/*TODO*/, Stream);
 356         Entry = SectionMap.size();
 357       }
 358     }
 359     if (F->hasGC()) {
 360       // Same for GC names.
 361       unsigned &Entry = GCMap[F->getGC()];
 362       if (!Entry) {
 363         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 364                           0/*TODO*/, Stream);
 365         Entry = GCMap.size();
 366       }
 367     }
 368   }
 369
 370   // Emit abbrev for globals, now that we know # sections and max alignment.
 371   unsigned SimpleGVarAbbrev = 0;
 372   if (!M->global_empty()) {
 373     // Add an abbrev for common globals with no visibility or thread localness.
 374     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 375     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 377                               Log2_32_Ceil(MaxGlobalType+1)));
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 381     if (MaxAlignment == 0)                                      // Alignment.
 382       Abbv->Add(BitCodeAbbrevOp(0));
 383     else {
 384       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 385       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 386                                Log2_32_Ceil(MaxEncAlignment+1)));
 387     }
 388     if (SectionMap.empty())                                    // Section.
 389       Abbv->Add(BitCodeAbbrevOp(0));
 390     else
 391       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 392                                Log2_32_Ceil(SectionMap.size()+1)));
 393     // Don't bother emitting vis + thread local.
 394     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 395   }
 396
 397   // Emit the global variable information.
 398   SmallVector<unsigned, 64> Vals;
 399   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 400        GV != E; ++GV) {
 401     unsigned AbbrevToUse = 0;
 402
 403     // GLOBALVAR: [type, isconst, initid,
 404     //             linkage, alignment, section, visibility, threadlocal]
 405     Vals.push_back(VE.getTypeID(GV->getType()));
 406     Vals.push_back(GV->isConstant());
 407     Vals.push_back(GV->isDeclaration() ? 0 :
 408                    (VE.getValueID(GV->getInitializer()) + 1));
 409     Vals.push_back(getEncodedLinkage(GV));
 410     Vals.push_back(Log2_32(GV->getAlignment())+1);
 411     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 412     if (GV->isThreadLocal() ||
 413         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 414       Vals.push_back(getEncodedVisibility(GV));
 415       Vals.push_back(GV->isThreadLocal());
 416     } else {
 417       AbbrevToUse = SimpleGVarAbbrev;
 418     }
 419
 420     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 421     Vals.clear();
 422   }
 423
 424   // Emit the function proto information.
 425   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 426     // FUNCTION:  [type, callingconv, isproto, paramattr,
 427     //             linkage, alignment, section, visibility, gc]
 428     Vals.push_back(VE.getTypeID(F->getType()));
 429     Vals.push_back(F->getCallingConv());
 430     Vals.push_back(F->isDeclaration());
 431     Vals.push_back(getEncodedLinkage(F));
 432     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 433     Vals.push_back(Log2_32(F->getAlignment())+1);
 434     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 435     Vals.push_back(getEncodedVisibility(F));
 436     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 437
 438     unsigned AbbrevToUse = 0;
 439     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 440     Vals.clear();
 441   }
 442
 443
 444   // Emit the alias information.
 445   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 446        AI != E; ++AI) {
 447     Vals.push_back(VE.getTypeID(AI->getType()));
 448     Vals.push_back(VE.getValueID(AI->getAliasee()));
 449     Vals.push_back(getEncodedLinkage(AI));
 450     Vals.push_back(getEncodedVisibility(AI));
 451     unsigned AbbrevToUse = 0;
 452     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 453     Vals.clear();
 454   }
 455 }
 456
 457
 458 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 459                            const ValueEnumerator &VE,
 460                            BitstreamWriter &Stream, bool isGlobal) {
 461   if (FirstVal == LastVal) return;
 462
 463   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 464
 465   unsigned AggregateAbbrev = 0;
 466   unsigned String8Abbrev = 0;
 467   unsigned CString7Abbrev = 0;
 468   unsigned CString6Abbrev = 0;
 469   unsigned MDString8Abbrev = 0;
 470   unsigned MDString6Abbrev = 0;
 471   // If this is a constant pool for the module, emit module-specific abbrevs.
 472   if (isGlobal) {
 473     // Abbrev for CST_CODE_AGGREGATE.
 474     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 475     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 478     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 479
 480     // Abbrev for CST_CODE_STRING.
 481     Abbv = new BitCodeAbbrev();
 482     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 485     String8Abbrev = Stream.EmitAbbrev(Abbv);
 486     // Abbrev for CST_CODE_CSTRING.
 487     Abbv = new BitCodeAbbrev();
 488     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 491     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 492     // Abbrev for CST_CODE_CSTRING.
 493     Abbv = new BitCodeAbbrev();
 494     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 497     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 498
 499     // Abbrev for CST_CODE_MDSTRING.
 500     Abbv = new BitCodeAbbrev();
 501     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 504     MDString8Abbrev = Stream.EmitAbbrev(Abbv);
 505     // Abbrev for CST_CODE_MDSTRING.
 506     Abbv = new BitCodeAbbrev();
 507     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_MDSTRING));
 508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 510     MDString6Abbrev = Stream.EmitAbbrev(Abbv);
 511   }
 512
 513   SmallVector<uint64_t, 64> Record;
 514
 515   const ValueEnumerator::ValueList &Vals = VE.getValues();
 516   const Type *LastTy = 0;
 517   for (unsigned i = FirstVal; i != LastVal; ++i) {
 518     const Value *V = Vals[i].first;
 519     // If we need to switch types, do so now.
 520     if (V->getType() != LastTy) {
 521       LastTy = V->getType();
 522       Record.push_back(VE.getTypeID(LastTy));
 523       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 524                         CONSTANTS_SETTYPE_ABBREV);
 525       Record.clear();
 526     }
 527
 528     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 529       Record.push_back(unsigned(IA->hasSideEffects()));
 530
 531       // Add the asm string.
 532       const std::string &AsmStr = IA->getAsmString();
 533       Record.push_back(AsmStr.size());
 534       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 535         Record.push_back(AsmStr[i]);
 536
 537       // Add the constraint string.
 538       const std::string &ConstraintStr = IA->getConstraintString();
 539       Record.push_back(ConstraintStr.size());
 540       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 541         Record.push_back(ConstraintStr[i]);
 542       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 543       Record.clear();
 544       continue;
 545     }
 546     const Constant *C = cast<Constant>(V);
 547     unsigned Code = -1U;
 548     unsigned AbbrevToUse = 0;
 549     if (C->isNullValue()) {
 550       Code = bitc::CST_CODE_NULL;
 551     } else if (isa<UndefValue>(C)) {
 552       Code = bitc::CST_CODE_UNDEF;
 553     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 554       if (IV->getBitWidth() <= 64) {
 555         int64_t V = IV->getSExtValue();
 556         if (V >= 0)
 557           Record.push_back(V << 1);
 558         else
 559           Record.push_back((-V << 1) | 1);
 560         Code = bitc::CST_CODE_INTEGER;
 561         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 562       } else {                             // Wide integers, > 64 bits in size.
 563         // We have an arbitrary precision integer value to write whose
 564         // bit width is > 64. However, in canonical unsigned integer
 565         // format it is likely that the high bits are going to be zero.
 566         // So, we only write the number of active words.
 567         unsigned NWords = IV->getValue().getActiveWords();
 568         const uint64_t *RawWords = IV->getValue().getRawData();
 569         for (unsigned i = 0; i != NWords; ++i) {
 570           int64_t V = RawWords[i];
 571           if (V >= 0)
 572             Record.push_back(V << 1);
 573           else
 574             Record.push_back((-V << 1) | 1);
 575         }
 576         Code = bitc::CST_CODE_WIDE_INTEGER;
 577       }
 578     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 579       Code = bitc::CST_CODE_FLOAT;
 580       const Type *Ty = CFP->getType();
 581       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 582         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 583       } else if (Ty == Type::X86_FP80Ty) {
 584         // api needed to prevent premature destruction
 585         // bits are not in the same order as a normal i80 APInt, compensate.
 586         APInt api = CFP->getValueAPF().bitcastToAPInt();
 587         const uint64_t *p = api.getRawData();
 588         Record.push_back((p[1] << 48) | (p[0] >> 16));
 589         Record.push_back(p[0] & 0xffffLL);
 590       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 591         APInt api = CFP->getValueAPF().bitcastToAPInt();
 592         const uint64_t *p = api.getRawData();
 593         Record.push_back(p[0]);
 594         Record.push_back(p[1]);
 595       } else {
 596         assert (0 && "Unknown FP type!");
 597       }
 598     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 599       // Emit constant strings specially.
 600       unsigned NumOps = C->getNumOperands();
 601       // If this is a null-terminated string, use the denser CSTRING encoding.
 602       if (C->getOperand(NumOps-1)->isNullValue()) {
 603         Code = bitc::CST_CODE_CSTRING;
 604         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 605       } else {
 606         Code = bitc::CST_CODE_STRING;
 607         AbbrevToUse = String8Abbrev;
 608       }
 609       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 610       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 611       for (unsigned i = 0; i != NumOps; ++i) {
 612         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 613         Record.push_back(V);
 614         isCStr7 &= (V & 128) == 0;
 615         if (isCStrChar6)
 616           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 617       }
 618
 619       if (isCStrChar6)
 620         AbbrevToUse = CString6Abbrev;
 621       else if (isCStr7)
 622         AbbrevToUse = CString7Abbrev;
 623     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 624                isa<ConstantVector>(V)) {
 625       Code = bitc::CST_CODE_AGGREGATE;
 626       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 627         Record.push_back(VE.getValueID(C->getOperand(i)));
 628       AbbrevToUse = AggregateAbbrev;
 629     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 630       switch (CE->getOpcode()) {
 631       default:
 632         if (Instruction::isCast(CE->getOpcode())) {
 633           Code = bitc::CST_CODE_CE_CAST;
 634           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 635           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 636           Record.push_back(VE.getValueID(C->getOperand(0)));
 637           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 638         } else {
 639           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 640           Code = bitc::CST_CODE_CE_BINOP;
 641           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 642           Record.push_back(VE.getValueID(C->getOperand(0)));
 643           Record.push_back(VE.getValueID(C->getOperand(1)));
 644         }
 645         break;
 646       case Instruction::GetElementPtr:
 647         Code = bitc::CST_CODE_CE_GEP;
 648         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 649           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 650           Record.push_back(VE.getValueID(C->getOperand(i)));
 651         }
 652         break;
 653       case Instruction::Select:
 654         Code = bitc::CST_CODE_CE_SELECT;
 655         Record.push_back(VE.getValueID(C->getOperand(0)));
 656         Record.push_back(VE.getValueID(C->getOperand(1)));
 657         Record.push_back(VE.getValueID(C->getOperand(2)));
 658         break;
 659       case Instruction::ExtractElement:
 660         Code = bitc::CST_CODE_CE_EXTRACTELT;
 661         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 662         Record.push_back(VE.getValueID(C->getOperand(0)));
 663         Record.push_back(VE.getValueID(C->getOperand(1)));
 664         break;
 665       case Instruction::InsertElement:
 666         Code = bitc::CST_CODE_CE_INSERTELT;
 667         Record.push_back(VE.getValueID(C->getOperand(0)));
 668         Record.push_back(VE.getValueID(C->getOperand(1)));
 669         Record.push_back(VE.getValueID(C->getOperand(2)));
 670         break;
 671       case Instruction::ShuffleVector:
 672         // If the return type and argument types are the same, this is a
 673         // standard shufflevector instruction.  If the types are different,
 674         // then the shuffle is widening or truncating the input vectors, and
 675         // the argument type must also be encoded.
 676         if (C->getType() == C->getOperand(0)->getType()) {
 677           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 678         } else {
 679           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 680           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 681         }
 682         Record.push_back(VE.getValueID(C->getOperand(0)));
 683         Record.push_back(VE.getValueID(C->getOperand(1)));
 684         Record.push_back(VE.getValueID(C->getOperand(2)));
 685         break;
 686       case Instruction::ICmp:
 687       case Instruction::FCmp:
 688         Code = bitc::CST_CODE_CE_CMP;
 689         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 690         Record.push_back(VE.getValueID(C->getOperand(0)));
 691         Record.push_back(VE.getValueID(C->getOperand(1)));
 692         Record.push_back(CE->getPredicate());
 693         break;
 694       }
 695     } else if (const MDString *S = dyn_cast<MDString>(C)) {
 696       Code = bitc::CST_CODE_MDSTRING;
 697       AbbrevToUse = MDString6Abbrev;
 698       for (unsigned i = 0, e = S->size(); i != e; ++i) {
 699         char V = S->begin()[i];
 700         Record.push_back(V);
 701
 702         if (!BitCodeAbbrevOp::isChar6(V))
 703           AbbrevToUse = MDString8Abbrev;
 704       }
 705     } else if (const MDNode *N = dyn_cast<MDNode>(C)) {
 706       Code = bitc::CST_CODE_MDNODE;
 707       for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 708         if (N->getElement(i)) {
 709           Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 710           Record.push_back(VE.getValueID(N->getElement(i)));
 711         } else {
 712           Record.push_back(VE.getTypeID(Type::VoidTy));
 713           Record.push_back(0);
 714         }
 715       }
 716     } else {
 717       llvm_unreachable("Unknown constant!");
 718     }
 719     Stream.EmitRecord(Code, Record, AbbrevToUse);
 720     Record.clear();
 721   }
 722
 723   Stream.ExitBlock();
 724 }
 725
 726 static void WriteModuleConstants(const ValueEnumerator &VE,
 727                                  BitstreamWriter &Stream) {
 728   const ValueEnumerator::ValueList &Vals = VE.getValues();
 729
 730   // Find the first constant to emit, which is the first non-globalvalue value.
 731   // We know globalvalues have been emitted by WriteModuleInfo.
 732   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 733     if (!isa<GlobalValue>(Vals[i].first)) {
 734       WriteConstants(i, Vals.size(), VE, Stream, true);
 735       return;
 736     }
 737   }
 738 }
 739
 740 /// PushValueAndType - The file has to encode both the value and type id for
 741 /// many values, because we need to know what type to create for forward
 742 /// references.  However, most operands are not forward references, so this type
 743 /// field is not needed.
 744 ///
 745 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 746 /// instruction ID, then it is a forward reference, and it also includes the
 747 /// type ID.
 748 static bool PushValueAndType(const Value *V, unsigned InstID,
 749                              SmallVector<unsigned, 64> &Vals,
 750                              ValueEnumerator &VE) {
 751   unsigned ValID = VE.getValueID(V);
 752   Vals.push_back(ValID);
 753   if (ValID >= InstID) {
 754     Vals.push_back(VE.getTypeID(V->getType()));
 755     return true;
 756   }
 757   return false;
 758 }
 759
 760 /// WriteInstruction - Emit an instruction to the specified stream.
 761 static void WriteInstruction(const Instruction &I, unsigned InstID,
 762                              ValueEnumerator &VE, BitstreamWriter &Stream,
 763                              SmallVector<unsigned, 64> &Vals) {
 764   unsigned Code = 0;
 765   unsigned AbbrevToUse = 0;
 766   switch (I.getOpcode()) {
 767   default:
 768     if (Instruction::isCast(I.getOpcode())) {
 769       Code = bitc::FUNC_CODE_INST_CAST;
 770       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 771         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 772       Vals.push_back(VE.getTypeID(I.getType()));
 773       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 774     } else {
 775       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 776       Code = bitc::FUNC_CODE_INST_BINOP;
 777       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 778         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 779       Vals.push_back(VE.getValueID(I.getOperand(1)));
 780       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 781     }
 782     break;
 783
 784   case Instruction::GetElementPtr:
 785     Code = bitc::FUNC_CODE_INST_GEP;
 786     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 787       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 788     break;
 789   case Instruction::ExtractValue: {
 790     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 791     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 792     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 793     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 794       Vals.push_back(*i);
 795     break;
 796   }
 797   case Instruction::InsertValue: {
 798     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 799     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 800     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 801     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 802     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 803       Vals.push_back(*i);
 804     break;
 805   }
 806   case Instruction::Select:
 807     Code = bitc::FUNC_CODE_INST_VSELECT;
 808     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 809     Vals.push_back(VE.getValueID(I.getOperand(2)));
 810     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 811     break;
 812   case Instruction::ExtractElement:
 813     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 814     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 815     Vals.push_back(VE.getValueID(I.getOperand(1)));
 816     break;
 817   case Instruction::InsertElement:
 818     Code = bitc::FUNC_CODE_INST_INSERTELT;
 819     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 820     Vals.push_back(VE.getValueID(I.getOperand(1)));
 821     Vals.push_back(VE.getValueID(I.getOperand(2)));
 822     break;
 823   case Instruction::ShuffleVector:
 824     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 825     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 826     Vals.push_back(VE.getValueID(I.getOperand(1)));
 827     Vals.push_back(VE.getValueID(I.getOperand(2)));
 828     break;
 829   case Instruction::ICmp:
 830   case Instruction::FCmp:
 831     // compare returning Int1Ty or vector of Int1Ty
 832     Code = bitc::FUNC_CODE_INST_CMP2;
 833     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 834     Vals.push_back(VE.getValueID(I.getOperand(1)));
 835     Vals.push_back(cast<CmpInst>(I).getPredicate());
 836     break;
 837
 838   case Instruction::Ret:
 839     {
 840       Code = bitc::FUNC_CODE_INST_RET;
 841       unsigned NumOperands = I.getNumOperands();
 842       if (NumOperands == 0)
 843         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 844       else if (NumOperands == 1) {
 845         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 846           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 847       } else {
 848         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 849           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 850       }
 851     }
 852     break;
 853   case Instruction::Br:
 854     {
 855       Code = bitc::FUNC_CODE_INST_BR;
 856       BranchInst &II(cast<BranchInst>(I));
 857       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 858       if (II.isConditional()) {
 859         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 860         Vals.push_back(VE.getValueID(II.getCondition()));
 861       }
 862     }
 863     break;
 864   case Instruction::Switch:
 865     Code = bitc::FUNC_CODE_INST_SWITCH;
 866     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 867     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 868       Vals.push_back(VE.getValueID(I.getOperand(i)));
 869     break;
 870   case Instruction::Invoke: {
 871     const InvokeInst *II = cast<InvokeInst>(&I);
 872     const Value *Callee(II->getCalledValue());
 873     const PointerType *PTy = cast<PointerType>(Callee->getType());
 874     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 875     Code = bitc::FUNC_CODE_INST_INVOKE;
 876
 877     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 878     Vals.push_back(II->getCallingConv());
 879     Vals.push_back(VE.getValueID(II->getNormalDest()));
 880     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 881     PushValueAndType(Callee, InstID, Vals, VE);
 882
 883     // Emit value #'s for the fixed parameters.
 884     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 885       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 886
 887     // Emit type/value pairs for varargs params.
 888     if (FTy->isVarArg()) {
 889       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 890            i != e; ++i)
 891         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 892     }
 893     break;
 894   }
 895   case Instruction::Unwind:
 896     Code = bitc::FUNC_CODE_INST_UNWIND;
 897     break;
 898   case Instruction::Unreachable:
 899     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 900     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 901     break;
 902
 903   case Instruction::PHI:
 904     Code = bitc::FUNC_CODE_INST_PHI;
 905     Vals.push_back(VE.getTypeID(I.getType()));
 906     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 907       Vals.push_back(VE.getValueID(I.getOperand(i)));
 908     break;
 909
 910   case Instruction::Malloc:
 911     Code = bitc::FUNC_CODE_INST_MALLOC;
 912     Vals.push_back(VE.getTypeID(I.getType()));
 913     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 914     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 915     break;
 916
 917   case Instruction::Free:
 918     Code = bitc::FUNC_CODE_INST_FREE;
 919     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 920     break;
 921
 922   case Instruction::Alloca:
 923     Code = bitc::FUNC_CODE_INST_ALLOCA;
 924     Vals.push_back(VE.getTypeID(I.getType()));
 925     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 926     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 927     break;
 928
 929   case Instruction::Load:
 930     Code = bitc::FUNC_CODE_INST_LOAD;
 931     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 932       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 933
 934     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 935     Vals.push_back(cast<LoadInst>(I).isVolatile());
 936     break;
 937   case Instruction::Store:
 938     Code = bitc::FUNC_CODE_INST_STORE2;
 939     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 940     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 941     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 942     Vals.push_back(cast<StoreInst>(I).isVolatile());
 943     break;
 944   case Instruction::Call: {
 945     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 946     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 947
 948     Code = bitc::FUNC_CODE_INST_CALL;
 949
 950     const CallInst *CI = cast<CallInst>(&I);
 951     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 952     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 953     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 954
 955     // Emit value #'s for the fixed parameters.
 956     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 957       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 958
 959     // Emit type/value pairs for varargs params.
 960     if (FTy->isVarArg()) {
 961       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 962       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 963            i != e; ++i)
 964         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 965     }
 966     break;
 967   }
 968   case Instruction::VAArg:
 969     Code = bitc::FUNC_CODE_INST_VAARG;
 970     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 971     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 972     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 973     break;
 974   }
 975
 976   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 977   Vals.clear();
 978 }
 979
 980 // Emit names for globals/functions etc.
 981 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 982                                   const ValueEnumerator &VE,
 983                                   BitstreamWriter &Stream) {
 984   if (VST.empty()) return;
 985   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 986
 987   // FIXME: Set up the abbrev, we know how many values there are!
 988   // FIXME: We know if the type names can use 7-bit ascii.
 989   SmallVector<unsigned, 64> NameVals;
 990
 991   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 992        SI != SE; ++SI) {
 993
 994     const ValueName &Name = *SI;
 995
 996     // Figure out the encoding to use for the name.
 997     bool is7Bit = true;
 998     bool isChar6 = true;
 999     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1000          C != E; ++C) {
1001       if (isChar6)
1002         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1003       if ((unsigned char)*C & 128) {
1004         is7Bit = false;
1005         break;  // don't bother scanning the rest.
1006       }
1007     }
1008
1009     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1010
1011     // VST_ENTRY:   [valueid, namechar x N]
1012     // VST_BBENTRY: [bbid, namechar x N]
1013     unsigned Code;
1014     if (isa<BasicBlock>(SI->getValue())) {
1015       Code = bitc::VST_CODE_BBENTRY;
1016       if (isChar6)
1017         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1018     } else {
1019       Code = bitc::VST_CODE_ENTRY;
1020       if (isChar6)
1021         AbbrevToUse = VST_ENTRY_6_ABBREV;
1022       else if (is7Bit)
1023         AbbrevToUse = VST_ENTRY_7_ABBREV;
1024     }
1025
1026     NameVals.push_back(VE.getValueID(SI->getValue()));
1027     for (const char *P = Name.getKeyData(),
1028          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1029       NameVals.push_back((unsigned char)*P);
1030
1031     // Emit the finished record.
1032     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1033     NameVals.clear();
1034   }
1035   Stream.ExitBlock();
1036 }
1037
1038 /// WriteFunction - Emit a function body to the module stream.
1039 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1040                           BitstreamWriter &Stream) {
1041   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1042   VE.incorporateFunction(F);
1043
1044   SmallVector<unsigned, 64> Vals;
1045
1046   // Emit the number of basic blocks, so the reader can create them ahead of
1047   // time.
1048   Vals.push_back(VE.getBasicBlocks().size());
1049   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1050   Vals.clear();
1051
1052   // If there are function-local constants, emit them now.
1053   unsigned CstStart, CstEnd;
1054   VE.getFunctionConstantRange(CstStart, CstEnd);
1055   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1056
1057   // Keep a running idea of what the instruction ID is.
1058   unsigned InstID = CstEnd;
1059
1060   // Finally, emit all the instructions, in order.
1061   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1062     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1063          I != E; ++I) {
1064       WriteInstruction(*I, InstID, VE, Stream, Vals);
1065       if (I->getType() != Type::VoidTy)
1066         ++InstID;
1067     }
1068
1069   // Emit names for all the instructions etc.
1070   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1071
1072   VE.purgeFunction();
1073   Stream.ExitBlock();
1074 }
1075
1076 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1077 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1078                                  const ValueEnumerator &VE,
1079                                  BitstreamWriter &Stream) {
1080   if (TST.empty()) return;
1081
1082   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1083
1084   // 7-bit fixed width VST_CODE_ENTRY strings.
1085   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1086   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1088                             Log2_32_Ceil(VE.getTypes().size()+1)));
1089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1091   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1092
1093   SmallVector<unsigned, 64> NameVals;
1094
1095   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1096        TI != TE; ++TI) {
1097     // TST_ENTRY: [typeid, namechar x N]
1098     NameVals.push_back(VE.getTypeID(TI->second));
1099
1100     const std::string &Str = TI->first;
1101     bool is7Bit = true;
1102     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1103       NameVals.push_back((unsigned char)Str[i]);
1104       if (Str[i] & 128)
1105         is7Bit = false;
1106     }
1107
1108     // Emit the finished record.
1109     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1110     NameVals.clear();
1111   }
1112
1113   Stream.ExitBlock();
1114 }
1115
1116 // Emit blockinfo, which defines the standard abbreviations etc.
1117 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1118   // We only want to emit block info records for blocks that have multiple
1119   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1120   // blocks can defined their abbrevs inline.
1121   Stream.EnterBlockInfoBlock(2);
1122
1123   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1124     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1127     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1128     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1129     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1130                                    Abbv) != VST_ENTRY_8_ABBREV)
1131       llvm_unreachable("Unexpected abbrev ordering!");
1132   }
1133
1134   { // 7-bit fixed width VST_ENTRY strings.
1135     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1136     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1138     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1139     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1140     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1141                                    Abbv) != VST_ENTRY_7_ABBREV)
1142       llvm_unreachable("Unexpected abbrev ordering!");
1143   }
1144   { // 6-bit char6 VST_ENTRY strings.
1145     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1146     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1150     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1151                                    Abbv) != VST_ENTRY_6_ABBREV)
1152       llvm_unreachable("Unexpected abbrev ordering!");
1153   }
1154   { // 6-bit char6 VST_BBENTRY strings.
1155     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1156     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1159     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1160     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1161                                    Abbv) != VST_BBENTRY_6_ABBREV)
1162       llvm_unreachable("Unexpected abbrev ordering!");
1163   }
1164
1165
1166
1167   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1168     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1169     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1170     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1171                               Log2_32_Ceil(VE.getTypes().size()+1)));
1172     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1173                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1174       llvm_unreachable("Unexpected abbrev ordering!");
1175   }
1176
1177   { // INTEGER abbrev for CONSTANTS_BLOCK.
1178     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1179     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1181     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1182                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1183       llvm_unreachable("Unexpected abbrev ordering!");
1184   }
1185
1186   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1187     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1188     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1191                               Log2_32_Ceil(VE.getTypes().size()+1)));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1193
1194     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1195                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1196       llvm_unreachable("Unexpected abbrev ordering!");
1197   }
1198   { // NULL abbrev for CONSTANTS_BLOCK.
1199     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1200     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1201     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1202                                    Abbv) != CONSTANTS_NULL_Abbrev)
1203       llvm_unreachable("Unexpected abbrev ordering!");
1204   }
1205
1206   // FIXME: This should only use space for first class types!
1207
1208   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1209     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1210     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1212     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1214     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1215                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1216       llvm_unreachable("Unexpected abbrev ordering!");
1217   }
1218   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1219     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1220     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1222     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1224     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1225                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1226       llvm_unreachable("Unexpected abbrev ordering!");
1227   }
1228   { // INST_CAST abbrev for FUNCTION_BLOCK.
1229     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1230     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1231     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1233                               Log2_32_Ceil(VE.getTypes().size()+1)));
1234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1235     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1236                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1237       llvm_unreachable("Unexpected abbrev ordering!");
1238   }
1239
1240   { // INST_RET abbrev for FUNCTION_BLOCK.
1241     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1242     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1243     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1244                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1245       llvm_unreachable("Unexpected abbrev ordering!");
1246   }
1247   { // INST_RET abbrev for FUNCTION_BLOCK.
1248     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1249     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1251     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1252                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1253       llvm_unreachable("Unexpected abbrev ordering!");
1254   }
1255   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1256     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1257     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1258     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1259                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1260       llvm_unreachable("Unexpected abbrev ordering!");
1261   }
1262
1263   Stream.ExitBlock();
1264 }
1265
1266
1267 /// WriteModule - Emit the specified module to the bitstream.
1268 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1269   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1270
1271   // Emit the version number if it is non-zero.
1272   if (CurVersion) {
1273     SmallVector<unsigned, 1> Vals;
1274     Vals.push_back(CurVersion);
1275     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1276   }
1277
1278   // Analyze the module, enumerating globals, functions, etc.
1279   ValueEnumerator VE(M);
1280
1281   // Emit blockinfo, which defines the standard abbreviations etc.
1282   WriteBlockInfo(VE, Stream);
1283
1284   // Emit information about parameter attributes.
1285   WriteAttributeTable(VE, Stream);
1286
1287   // Emit information describing all of the types in the module.
1288   WriteTypeTable(VE, Stream);
1289
1290   // Emit top-level description of module, including target triple, inline asm,
1291   // descriptors for global variables, and function prototype info.
1292   WriteModuleInfo(M, VE, Stream);
1293
1294   // Emit constants.
1295   WriteModuleConstants(VE, Stream);
1296
1297   // Emit function bodies.
1298   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1299     if (!I->isDeclaration())
1300       WriteFunction(*I, VE, Stream);
1301
1302   // Emit the type symbol table information.
1303   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1304
1305   // Emit names for globals/functions etc.
1306   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1307
1308   Stream.ExitBlock();
1309 }
1310
1311 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1312 /// header and trailer to make it compatible with the system archiver.  To do
1313 /// this we emit the following header, and then emit a trailer that pads the
1314 /// file out to be a multiple of 16 bytes.
1315 ///
1316 /// struct bc_header {
1317 ///   uint32_t Magic;         // 0x0B17C0DE
1318 ///   uint32_t Version;       // Version, currently always 0.
1319 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1320 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1321 ///   uint32_t CPUType;       // CPU specifier.
1322 ///   ... potentially more later ...
1323 /// };
1324 enum {
1325   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1326   DarwinBCHeaderSize = 5*4
1327 };
1328
1329 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1330                                const std::string &TT) {
1331   unsigned CPUType = ~0U;
1332
1333   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1334   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1335   // specific constants here because they are implicitly part of the Darwin ABI.
1336   enum {
1337     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1338     DARWIN_CPU_TYPE_X86        = 7,
1339     DARWIN_CPU_TYPE_POWERPC    = 18
1340   };
1341
1342   if (TT.find("x86_64-") == 0)
1343     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1344   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1345            TT[4] == '-' && TT[1] - '3' < 6)
1346     CPUType = DARWIN_CPU_TYPE_X86;
1347   else if (TT.find("powerpc-") == 0)
1348     CPUType = DARWIN_CPU_TYPE_POWERPC;
1349   else if (TT.find("powerpc64-") == 0)
1350     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1351
1352   // Traditional Bitcode starts after header.
1353   unsigned BCOffset = DarwinBCHeaderSize;
1354
1355   Stream.Emit(0x0B17C0DE, 32);
1356   Stream.Emit(0         , 32);  // Version.
1357   Stream.Emit(BCOffset  , 32);
1358   Stream.Emit(0         , 32);  // Filled in later.
1359   Stream.Emit(CPUType   , 32);
1360 }
1361
1362 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1363 /// finalize the header.
1364 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1365   // Update the size field in the header.
1366   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1367
1368   // If the file is not a multiple of 16 bytes, insert dummy padding.
1369   while (BufferSize & 15) {
1370     Stream.Emit(0, 8);
1371     ++BufferSize;
1372   }
1373 }
1374
1375
1376 /// WriteBitcodeToFile - Write the specified module to the specified output
1377 /// stream.
1378 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1379   raw_os_ostream RawOut(Out);
1380   // If writing to stdout, set binary mode.
1381   if (llvm::cout == Out)
1382     sys::Program::ChangeStdoutToBinary();
1383   WriteBitcodeToFile(M, RawOut);
1384 }
1385
1386 /// WriteBitcodeToFile - Write the specified module to the specified output
1387 /// stream.
1388 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1389   std::vector<unsigned char> Buffer;
1390   BitstreamWriter Stream(Buffer);
1391
1392   Buffer.reserve(256*1024);
1393
1394   WriteBitcodeToStream( M, Stream );
1395
1396   // If writing to stdout, set binary mode.
1397   if (&llvm::outs() == &Out)
1398     sys::Program::ChangeStdoutToBinary();
1399
1400   // Write the generated bitstream to "Out".
1401   Out.write((char*)&Buffer.front(), Buffer.size());
1402
1403   // Make sure it hits disk now.
1404   Out.flush();
1405 }
1406
1407 /// WriteBitcodeToStream - Write the specified module to the specified output
1408 /// stream.
1409 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1410   // If this is darwin, emit a file header and trailer if needed.
1411   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1412   if (isDarwin)
1413     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1414
1415   // Emit the file header.
1416   Stream.Emit((unsigned)'B', 8);
1417   Stream.Emit((unsigned)'C', 8);
1418   Stream.Emit(0x0, 4);
1419   Stream.Emit(0xC, 4);
1420   Stream.Emit(0xE, 4);
1421   Stream.Emit(0xD, 4);
1422
1423   // Emit the module.
1424   WriteModule(M, Stream);
1425
1426   if (isDarwin)
1427     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1428 }