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/Module.h"
  23 #include "llvm/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include "llvm/System/Program.h"
  29 using namespace llvm;
  30
  31 /// These are manifest constants used by the bitcode writer. They do not need to
  32 /// be kept in sync with the reader, but need to be consistent within this file.
  33 enum {
  34   CurVersion = 0,
  35
  36   // VALUE_SYMTAB_BLOCK abbrev id's.
  37   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  38   VST_ENTRY_7_ABBREV,
  39   VST_ENTRY_6_ABBREV,
  40   VST_BBENTRY_6_ABBREV,
  41
  42   // CONSTANTS_BLOCK abbrev id's.
  43   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  44   CONSTANTS_INTEGER_ABBREV,
  45   CONSTANTS_CE_CAST_Abbrev,
  46   CONSTANTS_NULL_Abbrev,
  47
  48   // FUNCTION_BLOCK abbrev id's.
  49   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  50   FUNCTION_INST_BINOP_ABBREV,
  51   FUNCTION_INST_CAST_ABBREV,
  52   FUNCTION_INST_RET_VOID_ABBREV,
  53   FUNCTION_INST_RET_VAL_ABBREV,
  54   FUNCTION_INST_UNREACHABLE_ABBREV
  55 };
  56
  57
  58 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  59   switch (Opcode) {
  60   default: assert(0 && "Unknown cast instruction!");
  61   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  62   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  63   case Instruction::SExt    : return bitc::CAST_SEXT;
  64   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  65   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  66   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  67   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  68   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  69   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  70   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  71   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  72   case Instruction::BitCast : return bitc::CAST_BITCAST;
  73   }
  74 }
  75
  76 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  77   switch (Opcode) {
  78   default: assert(0 && "Unknown binary instruction!");
  79   case Instruction::Add:  return bitc::BINOP_ADD;
  80   case Instruction::Sub:  return bitc::BINOP_SUB;
  81   case Instruction::Mul:  return bitc::BINOP_MUL;
  82   case Instruction::UDiv: return bitc::BINOP_UDIV;
  83   case Instruction::FDiv:
  84   case Instruction::SDiv: return bitc::BINOP_SDIV;
  85   case Instruction::URem: return bitc::BINOP_UREM;
  86   case Instruction::FRem:
  87   case Instruction::SRem: return bitc::BINOP_SREM;
  88   case Instruction::Shl:  return bitc::BINOP_SHL;
  89   case Instruction::LShr: return bitc::BINOP_LSHR;
  90   case Instruction::AShr: return bitc::BINOP_ASHR;
  91   case Instruction::And:  return bitc::BINOP_AND;
  92   case Instruction::Or:   return bitc::BINOP_OR;
  93   case Instruction::Xor:  return bitc::BINOP_XOR;
  94   }
  95 }
  96
  97
  98
  99 static void WriteStringRecord(unsigned Code, const std::string &Str,
 100                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 101   SmallVector<unsigned, 64> Vals;
 102
 103   // Code: [strchar x N]
 104   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 105     Vals.push_back(Str[i]);
 106
 107   // Emit the finished record.
 108   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 109 }
 110
 111 // Emit information about parameter attributes.
 112 static void WriteAttributeTable(const ValueEnumerator &VE,
 113                                 BitstreamWriter &Stream) {
 114   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 115   if (Attrs.empty()) return;
 116
 117   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 118
 119   SmallVector<uint64_t, 64> Record;
 120   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 121     const AttrListPtr &A = Attrs[i];
 122     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 123       const AttributeWithIndex &PAWI = A.getSlot(i);
 124       Record.push_back(PAWI.Index);
 125
 126       // FIXME: remove in LLVM 3.0
 127       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 128       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 129       // 11 bits.
 130       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 131       FauxAttr |= (1ull<<16)<<((PAWI.Attrs & Attribute::Alignment) >> 16);
 132       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 133
 134       Record.push_back(FauxAttr);
 135     }
 136
 137     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 138     Record.clear();
 139   }
 140
 141   Stream.ExitBlock();
 142 }
 143
 144 /// WriteTypeTable - Write out the type table for a module.
 145 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 146   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 147
 148   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 149   SmallVector<uint64_t, 64> TypeVals;
 150
 151   // Abbrev for TYPE_CODE_POINTER.
 152   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 153   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 155                             Log2_32_Ceil(VE.getTypes().size()+1)));
 156   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 157   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 158
 159   // Abbrev for TYPE_CODE_FUNCTION.
 160   Abbv = new BitCodeAbbrev();
 161   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 163   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 166                             Log2_32_Ceil(VE.getTypes().size()+1)));
 167   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 168
 169   // Abbrev for TYPE_CODE_STRUCT.
 170   Abbv = new BitCodeAbbrev();
 171   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 175                             Log2_32_Ceil(VE.getTypes().size()+1)));
 176   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 177
 178   // Abbrev for TYPE_CODE_ARRAY.
 179   Abbv = new BitCodeAbbrev();
 180   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 183                             Log2_32_Ceil(VE.getTypes().size()+1)));
 184   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 185
 186   // Emit an entry count so the reader can reserve space.
 187   TypeVals.push_back(TypeList.size());
 188   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 189   TypeVals.clear();
 190
 191   // Loop over all of the types, emitting each in turn.
 192   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 193     const Type *T = TypeList[i].first;
 194     int AbbrevToUse = 0;
 195     unsigned Code = 0;
 196
 197     switch (T->getTypeID()) {
 198     default: assert(0 && "Unknown type!");
 199     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 200     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 201     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 202     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 203     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 204     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 205     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 206     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 207     case Type::IntegerTyID:
 208       // INTEGER: [width]
 209       Code = bitc::TYPE_CODE_INTEGER;
 210       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 211       break;
 212     case Type::PointerTyID: {
 213       const PointerType *PTy = cast<PointerType>(T);
 214       // POINTER: [pointee type, address space]
 215       Code = bitc::TYPE_CODE_POINTER;
 216       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 217       unsigned AddressSpace = PTy->getAddressSpace();
 218       TypeVals.push_back(AddressSpace);
 219       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 220       break;
 221     }
 222     case Type::FunctionTyID: {
 223       const FunctionType *FT = cast<FunctionType>(T);
 224       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 225       Code = bitc::TYPE_CODE_FUNCTION;
 226       TypeVals.push_back(FT->isVarArg());
 227       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 228       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 229       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 230         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 231       AbbrevToUse = FunctionAbbrev;
 232       break;
 233     }
 234     case Type::StructTyID: {
 235       const StructType *ST = cast<StructType>(T);
 236       // STRUCT: [ispacked, eltty x N]
 237       Code = bitc::TYPE_CODE_STRUCT;
 238       TypeVals.push_back(ST->isPacked());
 239       // Output all of the element types.
 240       for (StructType::element_iterator I = ST->element_begin(),
 241            E = ST->element_end(); I != E; ++I)
 242         TypeVals.push_back(VE.getTypeID(*I));
 243       AbbrevToUse = StructAbbrev;
 244       break;
 245     }
 246     case Type::ArrayTyID: {
 247       const ArrayType *AT = cast<ArrayType>(T);
 248       // ARRAY: [numelts, eltty]
 249       Code = bitc::TYPE_CODE_ARRAY;
 250       TypeVals.push_back(AT->getNumElements());
 251       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 252       AbbrevToUse = ArrayAbbrev;
 253       break;
 254     }
 255     case Type::VectorTyID: {
 256       const VectorType *VT = cast<VectorType>(T);
 257       // VECTOR [numelts, eltty]
 258       Code = bitc::TYPE_CODE_VECTOR;
 259       TypeVals.push_back(VT->getNumElements());
 260       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 261       break;
 262     }
 263     }
 264
 265     // Emit the finished record.
 266     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 267     TypeVals.clear();
 268   }
 269
 270   Stream.ExitBlock();
 271 }
 272
 273 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 274   switch (GV->getLinkage()) {
 275   default: assert(0 && "Invalid linkage!");
 276   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 277   case GlobalValue::ExternalLinkage:     return 0;
 278   case GlobalValue::WeakLinkage:         return 1;
 279   case GlobalValue::AppendingLinkage:    return 2;
 280   case GlobalValue::InternalLinkage:     return 3;
 281   case GlobalValue::LinkOnceLinkage:     return 4;
 282   case GlobalValue::DLLImportLinkage:    return 5;
 283   case GlobalValue::DLLExportLinkage:    return 6;
 284   case GlobalValue::ExternalWeakLinkage: return 7;
 285   case GlobalValue::CommonLinkage:       return 8;
 286   }
 287 }
 288
 289 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 290   switch (GV->getVisibility()) {
 291   default: assert(0 && "Invalid visibility!");
 292   case GlobalValue::DefaultVisibility:   return 0;
 293   case GlobalValue::HiddenVisibility:    return 1;
 294   case GlobalValue::ProtectedVisibility: return 2;
 295   }
 296 }
 297
 298 // Emit top-level description of module, including target triple, inline asm,
 299 // descriptors for global variables, and function prototype info.
 300 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 301                             BitstreamWriter &Stream) {
 302   // Emit the list of dependent libraries for the Module.
 303   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 304     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 305
 306   // Emit various pieces of data attached to a module.
 307   if (!M->getTargetTriple().empty())
 308     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 309                       0/*TODO*/, Stream);
 310   if (!M->getDataLayout().empty())
 311     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 312                       0/*TODO*/, Stream);
 313   if (!M->getModuleInlineAsm().empty())
 314     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 315                       0/*TODO*/, Stream);
 316
 317   // Emit information about sections and GC, computing how many there are. Also
 318   // compute the maximum alignment value.
 319   std::map<std::string, unsigned> SectionMap;
 320   std::map<std::string, unsigned> GCMap;
 321   unsigned MaxAlignment = 0;
 322   unsigned MaxGlobalType = 0;
 323   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 324        GV != E; ++GV) {
 325     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 326     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 327
 328     if (!GV->hasSection()) continue;
 329     // Give section names unique ID's.
 330     unsigned &Entry = SectionMap[GV->getSection()];
 331     if (Entry != 0) continue;
 332     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 333                       0/*TODO*/, Stream);
 334     Entry = SectionMap.size();
 335   }
 336   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 337     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 338     if (F->hasSection()) {
 339       // Give section names unique ID's.
 340       unsigned &Entry = SectionMap[F->getSection()];
 341       if (!Entry) {
 342         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 343                           0/*TODO*/, Stream);
 344         Entry = SectionMap.size();
 345       }
 346     }
 347     if (F->hasGC()) {
 348       // Same for GC names.
 349       unsigned &Entry = GCMap[F->getGC()];
 350       if (!Entry) {
 351         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 352                           0/*TODO*/, Stream);
 353         Entry = GCMap.size();
 354       }
 355     }
 356   }
 357
 358   // Emit abbrev for globals, now that we know # sections and max alignment.
 359   unsigned SimpleGVarAbbrev = 0;
 360   if (!M->global_empty()) {
 361     // Add an abbrev for common globals with no visibility or thread localness.
 362     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 363     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 365                               Log2_32_Ceil(MaxGlobalType+1)));
 366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 368     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 369     if (MaxAlignment == 0)                                      // Alignment.
 370       Abbv->Add(BitCodeAbbrevOp(0));
 371     else {
 372       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 373       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 374                                Log2_32_Ceil(MaxEncAlignment+1)));
 375     }
 376     if (SectionMap.empty())                                    // Section.
 377       Abbv->Add(BitCodeAbbrevOp(0));
 378     else
 379       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 380                                Log2_32_Ceil(SectionMap.size()+1)));
 381     // Don't bother emitting vis + thread local.
 382     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 383   }
 384
 385   // Emit the global variable information.
 386   SmallVector<unsigned, 64> Vals;
 387   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 388        GV != E; ++GV) {
 389     unsigned AbbrevToUse = 0;
 390
 391     // GLOBALVAR: [type, isconst, initid,
 392     //             linkage, alignment, section, visibility, threadlocal]
 393     Vals.push_back(VE.getTypeID(GV->getType()));
 394     Vals.push_back(GV->isConstant());
 395     Vals.push_back(GV->isDeclaration() ? 0 :
 396                    (VE.getValueID(GV->getInitializer()) + 1));
 397     Vals.push_back(getEncodedLinkage(GV));
 398     Vals.push_back(Log2_32(GV->getAlignment())+1);
 399     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 400     if (GV->isThreadLocal() ||
 401         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 402       Vals.push_back(getEncodedVisibility(GV));
 403       Vals.push_back(GV->isThreadLocal());
 404     } else {
 405       AbbrevToUse = SimpleGVarAbbrev;
 406     }
 407
 408     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 409     Vals.clear();
 410   }
 411
 412   // Emit the function proto information.
 413   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 414     // FUNCTION:  [type, callingconv, isproto, paramattr,
 415     //             linkage, alignment, section, visibility, gc]
 416     Vals.push_back(VE.getTypeID(F->getType()));
 417     Vals.push_back(F->getCallingConv());
 418     Vals.push_back(F->isDeclaration());
 419     Vals.push_back(getEncodedLinkage(F));
 420     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 421     Vals.push_back(Log2_32(F->getAlignment())+1);
 422     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 423     Vals.push_back(getEncodedVisibility(F));
 424     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 425
 426     unsigned AbbrevToUse = 0;
 427     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 428     Vals.clear();
 429   }
 430
 431
 432   // Emit the alias information.
 433   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 434        AI != E; ++AI) {
 435     Vals.push_back(VE.getTypeID(AI->getType()));
 436     Vals.push_back(VE.getValueID(AI->getAliasee()));
 437     Vals.push_back(getEncodedLinkage(AI));
 438     Vals.push_back(getEncodedVisibility(AI));
 439     unsigned AbbrevToUse = 0;
 440     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 441     Vals.clear();
 442   }
 443 }
 444
 445
 446 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 447                            const ValueEnumerator &VE,
 448                            BitstreamWriter &Stream, bool isGlobal) {
 449   if (FirstVal == LastVal) return;
 450
 451   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 452
 453   unsigned AggregateAbbrev = 0;
 454   unsigned String8Abbrev = 0;
 455   unsigned CString7Abbrev = 0;
 456   unsigned CString6Abbrev = 0;
 457   // If this is a constant pool for the module, emit module-specific abbrevs.
 458   if (isGlobal) {
 459     // Abbrev for CST_CODE_AGGREGATE.
 460     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 461     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 464     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 465
 466     // Abbrev for CST_CODE_STRING.
 467     Abbv = new BitCodeAbbrev();
 468     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 471     String8Abbrev = Stream.EmitAbbrev(Abbv);
 472     // Abbrev for CST_CODE_CSTRING.
 473     Abbv = new BitCodeAbbrev();
 474     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 477     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 478     // Abbrev for CST_CODE_CSTRING.
 479     Abbv = new BitCodeAbbrev();
 480     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 483     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 484   }
 485
 486   SmallVector<uint64_t, 64> Record;
 487
 488   const ValueEnumerator::ValueList &Vals = VE.getValues();
 489   const Type *LastTy = 0;
 490   for (unsigned i = FirstVal; i != LastVal; ++i) {
 491     const Value *V = Vals[i].first;
 492     // If we need to switch types, do so now.
 493     if (V->getType() != LastTy) {
 494       LastTy = V->getType();
 495       Record.push_back(VE.getTypeID(LastTy));
 496       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 497                         CONSTANTS_SETTYPE_ABBREV);
 498       Record.clear();
 499     }
 500
 501     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 502       Record.push_back(unsigned(IA->hasSideEffects()));
 503
 504       // Add the asm string.
 505       const std::string &AsmStr = IA->getAsmString();
 506       Record.push_back(AsmStr.size());
 507       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 508         Record.push_back(AsmStr[i]);
 509
 510       // Add the constraint string.
 511       const std::string &ConstraintStr = IA->getConstraintString();
 512       Record.push_back(ConstraintStr.size());
 513       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 514         Record.push_back(ConstraintStr[i]);
 515       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 516       Record.clear();
 517       continue;
 518     }
 519     const Constant *C = cast<Constant>(V);
 520     unsigned Code = -1U;
 521     unsigned AbbrevToUse = 0;
 522     if (C->isNullValue()) {
 523       Code = bitc::CST_CODE_NULL;
 524     } else if (isa<UndefValue>(C)) {
 525       Code = bitc::CST_CODE_UNDEF;
 526     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 527       if (IV->getBitWidth() <= 64) {
 528         int64_t V = IV->getSExtValue();
 529         if (V >= 0)
 530           Record.push_back(V << 1);
 531         else
 532           Record.push_back((-V << 1) | 1);
 533         Code = bitc::CST_CODE_INTEGER;
 534         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 535       } else {                             // Wide integers, > 64 bits in size.
 536         // We have an arbitrary precision integer value to write whose
 537         // bit width is > 64. However, in canonical unsigned integer
 538         // format it is likely that the high bits are going to be zero.
 539         // So, we only write the number of active words.
 540         unsigned NWords = IV->getValue().getActiveWords();
 541         const uint64_t *RawWords = IV->getValue().getRawData();
 542         for (unsigned i = 0; i != NWords; ++i) {
 543           int64_t V = RawWords[i];
 544           if (V >= 0)
 545             Record.push_back(V << 1);
 546           else
 547             Record.push_back((-V << 1) | 1);
 548         }
 549         Code = bitc::CST_CODE_WIDE_INTEGER;
 550       }
 551     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 552       Code = bitc::CST_CODE_FLOAT;
 553       const Type *Ty = CFP->getType();
 554       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 555         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 556       } else if (Ty == Type::X86_FP80Ty) {
 557         // api needed to prevent premature destruction
 558         APInt api = CFP->getValueAPF().bitcastToAPInt();
 559         const uint64_t *p = api.getRawData();
 560         Record.push_back(p[0]);
 561         Record.push_back((uint16_t)p[1]);
 562       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 563         APInt api = CFP->getValueAPF().bitcastToAPInt();
 564         const uint64_t *p = api.getRawData();
 565         Record.push_back(p[0]);
 566         Record.push_back(p[1]);
 567       } else {
 568         assert (0 && "Unknown FP type!");
 569       }
 570     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 571       // Emit constant strings specially.
 572       unsigned NumOps = C->getNumOperands();
 573       // If this is a null-terminated string, use the denser CSTRING encoding.
 574       if (C->getOperand(NumOps-1)->isNullValue()) {
 575         Code = bitc::CST_CODE_CSTRING;
 576         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 577       } else {
 578         Code = bitc::CST_CODE_STRING;
 579         AbbrevToUse = String8Abbrev;
 580       }
 581       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 582       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 583       for (unsigned i = 0; i != NumOps; ++i) {
 584         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 585         Record.push_back(V);
 586         isCStr7 &= (V & 128) == 0;
 587         if (isCStrChar6)
 588           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 589       }
 590
 591       if (isCStrChar6)
 592         AbbrevToUse = CString6Abbrev;
 593       else if (isCStr7)
 594         AbbrevToUse = CString7Abbrev;
 595     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 596                isa<ConstantVector>(V)) {
 597       Code = bitc::CST_CODE_AGGREGATE;
 598       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 599         Record.push_back(VE.getValueID(C->getOperand(i)));
 600       AbbrevToUse = AggregateAbbrev;
 601     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 602       switch (CE->getOpcode()) {
 603       default:
 604         if (Instruction::isCast(CE->getOpcode())) {
 605           Code = bitc::CST_CODE_CE_CAST;
 606           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 607           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 608           Record.push_back(VE.getValueID(C->getOperand(0)));
 609           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 610         } else {
 611           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 612           Code = bitc::CST_CODE_CE_BINOP;
 613           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 614           Record.push_back(VE.getValueID(C->getOperand(0)));
 615           Record.push_back(VE.getValueID(C->getOperand(1)));
 616         }
 617         break;
 618       case Instruction::GetElementPtr:
 619         Code = bitc::CST_CODE_CE_GEP;
 620         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 621           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 622           Record.push_back(VE.getValueID(C->getOperand(i)));
 623         }
 624         break;
 625       case Instruction::Select:
 626         Code = bitc::CST_CODE_CE_SELECT;
 627         Record.push_back(VE.getValueID(C->getOperand(0)));
 628         Record.push_back(VE.getValueID(C->getOperand(1)));
 629         Record.push_back(VE.getValueID(C->getOperand(2)));
 630         break;
 631       case Instruction::ExtractElement:
 632         Code = bitc::CST_CODE_CE_EXTRACTELT;
 633         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 634         Record.push_back(VE.getValueID(C->getOperand(0)));
 635         Record.push_back(VE.getValueID(C->getOperand(1)));
 636         break;
 637       case Instruction::InsertElement:
 638         Code = bitc::CST_CODE_CE_INSERTELT;
 639         Record.push_back(VE.getValueID(C->getOperand(0)));
 640         Record.push_back(VE.getValueID(C->getOperand(1)));
 641         Record.push_back(VE.getValueID(C->getOperand(2)));
 642         break;
 643       case Instruction::ShuffleVector:
 644         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 645         Record.push_back(VE.getValueID(C->getOperand(0)));
 646         Record.push_back(VE.getValueID(C->getOperand(1)));
 647         Record.push_back(VE.getValueID(C->getOperand(2)));
 648         break;
 649       case Instruction::ICmp:
 650       case Instruction::FCmp:
 651       case Instruction::VICmp:
 652       case Instruction::VFCmp:
 653         if (isa<VectorType>(C->getOperand(0)->getType())
 654             && (CE->getOpcode() == Instruction::ICmp
 655                 || CE->getOpcode() == Instruction::FCmp)) {
 656           // compare returning vector of Int1Ty
 657           assert(0 && "Unsupported constant!");
 658         } else {
 659           Code = bitc::CST_CODE_CE_CMP;
 660         }
 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         Record.push_back(CE->getPredicate());
 665         break;
 666       }
 667     } else {
 668       assert(0 && "Unknown constant!");
 669     }
 670     Stream.EmitRecord(Code, Record, AbbrevToUse);
 671     Record.clear();
 672   }
 673
 674   Stream.ExitBlock();
 675 }
 676
 677 static void WriteModuleConstants(const ValueEnumerator &VE,
 678                                  BitstreamWriter &Stream) {
 679   const ValueEnumerator::ValueList &Vals = VE.getValues();
 680
 681   // Find the first constant to emit, which is the first non-globalvalue value.
 682   // We know globalvalues have been emitted by WriteModuleInfo.
 683   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 684     if (!isa<GlobalValue>(Vals[i].first)) {
 685       WriteConstants(i, Vals.size(), VE, Stream, true);
 686       return;
 687     }
 688   }
 689 }
 690
 691 /// PushValueAndType - The file has to encode both the value and type id for
 692 /// many values, because we need to know what type to create for forward
 693 /// references.  However, most operands are not forward references, so this type
 694 /// field is not needed.
 695 ///
 696 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 697 /// instruction ID, then it is a forward reference, and it also includes the
 698 /// type ID.
 699 static bool PushValueAndType(Value *V, unsigned InstID,
 700                              SmallVector<unsigned, 64> &Vals,
 701                              ValueEnumerator &VE) {
 702   unsigned ValID = VE.getValueID(V);
 703   Vals.push_back(ValID);
 704   if (ValID >= InstID) {
 705     Vals.push_back(VE.getTypeID(V->getType()));
 706     return true;
 707   }
 708   return false;
 709 }
 710
 711 /// WriteInstruction - Emit an instruction to the specified stream.
 712 static void WriteInstruction(const Instruction &I, unsigned InstID,
 713                              ValueEnumerator &VE, BitstreamWriter &Stream,
 714                              SmallVector<unsigned, 64> &Vals) {
 715   unsigned Code = 0;
 716   unsigned AbbrevToUse = 0;
 717   switch (I.getOpcode()) {
 718   default:
 719     if (Instruction::isCast(I.getOpcode())) {
 720       Code = bitc::FUNC_CODE_INST_CAST;
 721       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 722         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 723       Vals.push_back(VE.getTypeID(I.getType()));
 724       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 725     } else {
 726       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 727       Code = bitc::FUNC_CODE_INST_BINOP;
 728       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 729         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 730       Vals.push_back(VE.getValueID(I.getOperand(1)));
 731       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 732     }
 733     break;
 734
 735   case Instruction::GetElementPtr:
 736     Code = bitc::FUNC_CODE_INST_GEP;
 737     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 738       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 739     break;
 740   case Instruction::ExtractValue: {
 741     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 742     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 743     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 744     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 745       Vals.push_back(*i);
 746     break;
 747   }
 748   case Instruction::InsertValue: {
 749     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 750     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 751     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 752     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 753     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 754       Vals.push_back(*i);
 755     break;
 756   }
 757   case Instruction::Select:
 758     Code = bitc::FUNC_CODE_INST_VSELECT;
 759     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 760     Vals.push_back(VE.getValueID(I.getOperand(2)));
 761     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 762     break;
 763   case Instruction::ExtractElement:
 764     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 765     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 766     Vals.push_back(VE.getValueID(I.getOperand(1)));
 767     break;
 768   case Instruction::InsertElement:
 769     Code = bitc::FUNC_CODE_INST_INSERTELT;
 770     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 771     Vals.push_back(VE.getValueID(I.getOperand(1)));
 772     Vals.push_back(VE.getValueID(I.getOperand(2)));
 773     break;
 774   case Instruction::ShuffleVector:
 775     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 776     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 777     Vals.push_back(VE.getValueID(I.getOperand(1)));
 778     Vals.push_back(VE.getValueID(I.getOperand(2)));
 779     break;
 780   case Instruction::ICmp:
 781   case Instruction::FCmp:
 782   case Instruction::VICmp:
 783   case Instruction::VFCmp:
 784     if (I.getOpcode() == Instruction::ICmp
 785         || I.getOpcode() == Instruction::FCmp) {
 786       // compare returning Int1Ty or vector of Int1Ty
 787       Code = bitc::FUNC_CODE_INST_CMP2;
 788     } else {
 789       Code = bitc::FUNC_CODE_INST_CMP;
 790     }
 791     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 792     Vals.push_back(VE.getValueID(I.getOperand(1)));
 793     Vals.push_back(cast<CmpInst>(I).getPredicate());
 794     break;
 795
 796   case Instruction::Ret:
 797     {
 798       Code = bitc::FUNC_CODE_INST_RET;
 799       unsigned NumOperands = I.getNumOperands();
 800       if (NumOperands == 0)
 801         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 802       else if (NumOperands == 1) {
 803         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 804           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 805       } else {
 806         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 807           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 808       }
 809     }
 810     break;
 811   case Instruction::Br:
 812     Code = bitc::FUNC_CODE_INST_BR;
 813     Vals.push_back(VE.getValueID(I.getOperand(0)));
 814     if (cast<BranchInst>(I).isConditional()) {
 815       Vals.push_back(VE.getValueID(I.getOperand(1)));
 816       Vals.push_back(VE.getValueID(I.getOperand(2)));
 817     }
 818     break;
 819   case Instruction::Switch:
 820     Code = bitc::FUNC_CODE_INST_SWITCH;
 821     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 822     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 823       Vals.push_back(VE.getValueID(I.getOperand(i)));
 824     break;
 825   case Instruction::Invoke: {
 826     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 827     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 828     Code = bitc::FUNC_CODE_INST_INVOKE;
 829
 830     const InvokeInst *II = cast<InvokeInst>(&I);
 831     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 832     Vals.push_back(II->getCallingConv());
 833     Vals.push_back(VE.getValueID(I.getOperand(1)));      // normal dest
 834     Vals.push_back(VE.getValueID(I.getOperand(2)));      // unwind dest
 835     PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
 836
 837     // Emit value #'s for the fixed parameters.
 838     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 839       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 840
 841     // Emit type/value pairs for varargs params.
 842     if (FTy->isVarArg()) {
 843       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 844            i != e; ++i)
 845         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 846     }
 847     break;
 848   }
 849   case Instruction::Unwind:
 850     Code = bitc::FUNC_CODE_INST_UNWIND;
 851     break;
 852   case Instruction::Unreachable:
 853     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 854     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 855     break;
 856
 857   case Instruction::PHI:
 858     Code = bitc::FUNC_CODE_INST_PHI;
 859     Vals.push_back(VE.getTypeID(I.getType()));
 860     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 861       Vals.push_back(VE.getValueID(I.getOperand(i)));
 862     break;
 863
 864   case Instruction::Malloc:
 865     Code = bitc::FUNC_CODE_INST_MALLOC;
 866     Vals.push_back(VE.getTypeID(I.getType()));
 867     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 868     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 869     break;
 870
 871   case Instruction::Free:
 872     Code = bitc::FUNC_CODE_INST_FREE;
 873     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 874     break;
 875
 876   case Instruction::Alloca:
 877     Code = bitc::FUNC_CODE_INST_ALLOCA;
 878     Vals.push_back(VE.getTypeID(I.getType()));
 879     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 880     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 881     break;
 882
 883   case Instruction::Load:
 884     Code = bitc::FUNC_CODE_INST_LOAD;
 885     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 886       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 887
 888     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 889     Vals.push_back(cast<LoadInst>(I).isVolatile());
 890     break;
 891   case Instruction::Store:
 892     Code = bitc::FUNC_CODE_INST_STORE2;
 893     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 894     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 895     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 896     Vals.push_back(cast<StoreInst>(I).isVolatile());
 897     break;
 898   case Instruction::Call: {
 899     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 900     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 901
 902     Code = bitc::FUNC_CODE_INST_CALL;
 903
 904     const CallInst *CI = cast<CallInst>(&I);
 905     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 906     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 907     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 908
 909     // Emit value #'s for the fixed parameters.
 910     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 911       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 912
 913     // Emit type/value pairs for varargs params.
 914     if (FTy->isVarArg()) {
 915       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 916       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 917            i != e; ++i)
 918         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 919     }
 920     break;
 921   }
 922   case Instruction::VAArg:
 923     Code = bitc::FUNC_CODE_INST_VAARG;
 924     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 925     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 926     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 927     break;
 928   }
 929
 930   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 931   Vals.clear();
 932 }
 933
 934 // Emit names for globals/functions etc.
 935 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 936                                   const ValueEnumerator &VE,
 937                                   BitstreamWriter &Stream) {
 938   if (VST.empty()) return;
 939   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 940
 941   // FIXME: Set up the abbrev, we know how many values there are!
 942   // FIXME: We know if the type names can use 7-bit ascii.
 943   SmallVector<unsigned, 64> NameVals;
 944
 945   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 946        SI != SE; ++SI) {
 947
 948     const ValueName &Name = *SI;
 949
 950     // Figure out the encoding to use for the name.
 951     bool is7Bit = true;
 952     bool isChar6 = true;
 953     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 954          C != E; ++C) {
 955       if (isChar6)
 956         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 957       if ((unsigned char)*C & 128) {
 958         is7Bit = false;
 959         break;  // don't bother scanning the rest.
 960       }
 961     }
 962
 963     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 964
 965     // VST_ENTRY:   [valueid, namechar x N]
 966     // VST_BBENTRY: [bbid, namechar x N]
 967     unsigned Code;
 968     if (isa<BasicBlock>(SI->getValue())) {
 969       Code = bitc::VST_CODE_BBENTRY;
 970       if (isChar6)
 971         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 972     } else {
 973       Code = bitc::VST_CODE_ENTRY;
 974       if (isChar6)
 975         AbbrevToUse = VST_ENTRY_6_ABBREV;
 976       else if (is7Bit)
 977         AbbrevToUse = VST_ENTRY_7_ABBREV;
 978     }
 979
 980     NameVals.push_back(VE.getValueID(SI->getValue()));
 981     for (const char *P = Name.getKeyData(),
 982          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 983       NameVals.push_back((unsigned char)*P);
 984
 985     // Emit the finished record.
 986     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 987     NameVals.clear();
 988   }
 989   Stream.ExitBlock();
 990 }
 991
 992 /// WriteFunction - Emit a function body to the module stream.
 993 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 994                           BitstreamWriter &Stream) {
 995   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
 996   VE.incorporateFunction(F);
 997
 998   SmallVector<unsigned, 64> Vals;
 999
1000   // Emit the number of basic blocks, so the reader can create them ahead of
1001   // time.
1002   Vals.push_back(VE.getBasicBlocks().size());
1003   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1004   Vals.clear();
1005
1006   // If there are function-local constants, emit them now.
1007   unsigned CstStart, CstEnd;
1008   VE.getFunctionConstantRange(CstStart, CstEnd);
1009   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1010
1011   // Keep a running idea of what the instruction ID is.
1012   unsigned InstID = CstEnd;
1013
1014   // Finally, emit all the instructions, in order.
1015   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1016     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1017          I != E; ++I) {
1018       WriteInstruction(*I, InstID, VE, Stream, Vals);
1019       if (I->getType() != Type::VoidTy)
1020         ++InstID;
1021     }
1022
1023   // Emit names for all the instructions etc.
1024   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1025
1026   VE.purgeFunction();
1027   Stream.ExitBlock();
1028 }
1029
1030 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1031 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1032                                  const ValueEnumerator &VE,
1033                                  BitstreamWriter &Stream) {
1034   if (TST.empty()) return;
1035
1036   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1037
1038   // 7-bit fixed width VST_CODE_ENTRY strings.
1039   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1040   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1042                             Log2_32_Ceil(VE.getTypes().size()+1)));
1043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1045   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1046
1047   SmallVector<unsigned, 64> NameVals;
1048
1049   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1050        TI != TE; ++TI) {
1051     // TST_ENTRY: [typeid, namechar x N]
1052     NameVals.push_back(VE.getTypeID(TI->second));
1053
1054     const std::string &Str = TI->first;
1055     bool is7Bit = true;
1056     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1057       NameVals.push_back((unsigned char)Str[i]);
1058       if (Str[i] & 128)
1059         is7Bit = false;
1060     }
1061
1062     // Emit the finished record.
1063     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1064     NameVals.clear();
1065   }
1066
1067   Stream.ExitBlock();
1068 }
1069
1070 // Emit blockinfo, which defines the standard abbreviations etc.
1071 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1072   // We only want to emit block info records for blocks that have multiple
1073   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1074   // blocks can defined their abbrevs inline.
1075   Stream.EnterBlockInfoBlock(2);
1076
1077   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1078     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1079     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1080     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1081     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1082     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1083     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1084                                    Abbv) != VST_ENTRY_8_ABBREV)
1085       assert(0 && "Unexpected abbrev ordering!");
1086   }
1087
1088   { // 7-bit fixed width VST_ENTRY strings.
1089     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1090     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1091     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1092     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1093     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1094     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1095                                    Abbv) != VST_ENTRY_7_ABBREV)
1096       assert(0 && "Unexpected abbrev ordering!");
1097   }
1098   { // 6-bit char6 VST_ENTRY strings.
1099     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1100     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1101     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1104     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1105                                    Abbv) != VST_ENTRY_6_ABBREV)
1106       assert(0 && "Unexpected abbrev ordering!");
1107   }
1108   { // 6-bit char6 VST_BBENTRY strings.
1109     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1110     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1111     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1112     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1113     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1114     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1115                                    Abbv) != VST_BBENTRY_6_ABBREV)
1116       assert(0 && "Unexpected abbrev ordering!");
1117   }
1118
1119
1120
1121   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1122     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1123     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1125                               Log2_32_Ceil(VE.getTypes().size()+1)));
1126     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1127                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1128       assert(0 && "Unexpected abbrev ordering!");
1129   }
1130
1131   { // INTEGER abbrev for CONSTANTS_BLOCK.
1132     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1133     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1134     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1135     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1136                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1137       assert(0 && "Unexpected abbrev ordering!");
1138   }
1139
1140   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1141     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1142     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1143     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1144     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1145                               Log2_32_Ceil(VE.getTypes().size()+1)));
1146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1147
1148     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1149                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1150       assert(0 && "Unexpected abbrev ordering!");
1151   }
1152   { // NULL abbrev for CONSTANTS_BLOCK.
1153     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1154     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1155     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1156                                    Abbv) != CONSTANTS_NULL_Abbrev)
1157       assert(0 && "Unexpected abbrev ordering!");
1158   }
1159
1160   // FIXME: This should only use space for first class types!
1161
1162   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1163     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1164     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1168     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1169                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1170       assert(0 && "Unexpected abbrev ordering!");
1171   }
1172   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1173     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1174     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1178     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1179                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1180       assert(0 && "Unexpected abbrev ordering!");
1181   }
1182   { // INST_CAST abbrev for FUNCTION_BLOCK.
1183     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1184     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1185     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1187                               Log2_32_Ceil(VE.getTypes().size()+1)));
1188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1189     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1190                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1191       assert(0 && "Unexpected abbrev ordering!");
1192   }
1193
1194   { // INST_RET abbrev for FUNCTION_BLOCK.
1195     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1196     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1197     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1198                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1199       assert(0 && "Unexpected abbrev ordering!");
1200   }
1201   { // INST_RET abbrev for FUNCTION_BLOCK.
1202     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1203     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1205     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1206                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1207       assert(0 && "Unexpected abbrev ordering!");
1208   }
1209   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1210     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1211     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1212     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1213                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1214       assert(0 && "Unexpected abbrev ordering!");
1215   }
1216
1217   Stream.ExitBlock();
1218 }
1219
1220
1221 /// WriteModule - Emit the specified module to the bitstream.
1222 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1223   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1224
1225   // Emit the version number if it is non-zero.
1226   if (CurVersion) {
1227     SmallVector<unsigned, 1> Vals;
1228     Vals.push_back(CurVersion);
1229     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1230   }
1231
1232   // Analyze the module, enumerating globals, functions, etc.
1233   ValueEnumerator VE(M);
1234
1235   // Emit blockinfo, which defines the standard abbreviations etc.
1236   WriteBlockInfo(VE, Stream);
1237
1238   // Emit information about parameter attributes.
1239   WriteAttributeTable(VE, Stream);
1240
1241   // Emit information describing all of the types in the module.
1242   WriteTypeTable(VE, Stream);
1243
1244   // Emit top-level description of module, including target triple, inline asm,
1245   // descriptors for global variables, and function prototype info.
1246   WriteModuleInfo(M, VE, Stream);
1247
1248   // Emit constants.
1249   WriteModuleConstants(VE, Stream);
1250
1251   // If we have any aggregate values in the value table, purge them - these can
1252   // only be used to initialize global variables.  Doing so makes the value
1253   // namespace smaller for code in functions.
1254   int NumNonAggregates = VE.PurgeAggregateValues();
1255   if (NumNonAggregates != -1) {
1256     SmallVector<unsigned, 1> Vals;
1257     Vals.push_back(NumNonAggregates);
1258     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1259   }
1260
1261   // Emit function bodies.
1262   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1263     if (!I->isDeclaration())
1264       WriteFunction(*I, VE, Stream);
1265
1266   // Emit the type symbol table information.
1267   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1268
1269   // Emit names for globals/functions etc.
1270   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1271
1272   Stream.ExitBlock();
1273 }
1274
1275 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1276 /// header and trailer to make it compatible with the system archiver.  To do
1277 /// this we emit the following header, and then emit a trailer that pads the
1278 /// file out to be a multiple of 16 bytes.
1279 ///
1280 /// struct bc_header {
1281 ///   uint32_t Magic;         // 0x0B17C0DE
1282 ///   uint32_t Version;       // Version, currently always 0.
1283 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1284 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1285 ///   uint32_t CPUType;       // CPU specifier.
1286 ///   ... potentially more later ...
1287 /// };
1288 enum {
1289   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1290   DarwinBCHeaderSize = 5*4
1291 };
1292
1293 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1294                                const std::string &TT) {
1295   unsigned CPUType = ~0U;
1296
1297   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1298   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1299   // specific constants here because they are implicitly part of the Darwin ABI.
1300   enum {
1301     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1302     DARWIN_CPU_TYPE_X86        = 7,
1303     DARWIN_CPU_TYPE_POWERPC    = 18
1304   };
1305
1306   if (TT.find("x86_64-") == 0)
1307     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1308   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1309            TT[4] == '-' && TT[1] - '3' < 6)
1310     CPUType = DARWIN_CPU_TYPE_X86;
1311   else if (TT.find("powerpc-") == 0)
1312     CPUType = DARWIN_CPU_TYPE_POWERPC;
1313   else if (TT.find("powerpc64-") == 0)
1314     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1315
1316   // Traditional Bitcode starts after header.
1317   unsigned BCOffset = DarwinBCHeaderSize;
1318
1319   Stream.Emit(0x0B17C0DE, 32);
1320   Stream.Emit(0         , 32);  // Version.
1321   Stream.Emit(BCOffset  , 32);
1322   Stream.Emit(0         , 32);  // Filled in later.
1323   Stream.Emit(CPUType   , 32);
1324 }
1325
1326 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1327 /// finalize the header.
1328 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1329   // Update the size field in the header.
1330   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1331
1332   // If the file is not a multiple of 16 bytes, insert dummy padding.
1333   while (BufferSize & 15) {
1334     Stream.Emit(0, 8);
1335     ++BufferSize;
1336   }
1337 }
1338
1339
1340 /// WriteBitcodeToFile - Write the specified module to the specified output
1341 /// stream.
1342 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1343   raw_os_ostream RawOut(Out);
1344   // If writing to stdout, set binary mode.
1345   if (llvm::cout == Out)
1346     sys::Program::ChangeStdoutToBinary();
1347   WriteBitcodeToFile(M, RawOut);
1348 }
1349
1350 /// WriteBitcodeToFile - Write the specified module to the specified output
1351 /// stream.
1352 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1353   std::vector<unsigned char> Buffer;
1354   BitstreamWriter Stream(Buffer);
1355
1356   Buffer.reserve(256*1024);
1357
1358   // If this is darwin, emit a file header and trailer if needed.
1359   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1360   if (isDarwin)
1361     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1362
1363   // Emit the file header.
1364   Stream.Emit((unsigned)'B', 8);
1365   Stream.Emit((unsigned)'C', 8);
1366   Stream.Emit(0x0, 4);
1367   Stream.Emit(0xC, 4);
1368   Stream.Emit(0xE, 4);
1369   Stream.Emit(0xD, 4);
1370
1371   // Emit the module.
1372   WriteModule(M, Stream);
1373
1374   if (isDarwin)
1375     EmitDarwinBCTrailer(Stream, Buffer.size());
1376
1377
1378   // If writing to stdout, set binary mode.
1379   if (&llvm::outs() == &Out)
1380     sys::Program::ChangeStdoutToBinary();
1381
1382   // Write the generated bitstream to "Out".
1383   Out.write((char*)&Buffer.front(), Buffer.size());
1384
1385   // Make sure it hits disk now.
1386   Out.flush();
1387 }