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/Operator.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/raw_ostream.h"
  29 #include "llvm/System/Program.h"
  30 using namespace llvm;
  31
  32 /// These are manifest constants used by the bitcode writer. They do not need to
  33 /// be kept in sync with the reader, but need to be consistent within this file.
  34 enum {
  35   CurVersion = 0,
  36
  37   // VALUE_SYMTAB_BLOCK abbrev id's.
  38   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  39   VST_ENTRY_7_ABBREV,
  40   VST_ENTRY_6_ABBREV,
  41   VST_BBENTRY_6_ABBREV,
  42
  43   // CONSTANTS_BLOCK abbrev id's.
  44   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  45   CONSTANTS_INTEGER_ABBREV,
  46   CONSTANTS_CE_CAST_Abbrev,
  47   CONSTANTS_NULL_Abbrev,
  48
  49   // FUNCTION_BLOCK abbrev id's.
  50   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  51   FUNCTION_INST_BINOP_ABBREV,
  52   FUNCTION_INST_BINOP_FLAGS_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 static uint64_t GetOptimizationFlags(const Value *V) {
 458   uint64_t Flags = 0;
 459
 460   if (const OverflowingBinaryOperator *OBO =
 461         dyn_cast<OverflowingBinaryOperator>(V)) {
 462     if (OBO->hasNoSignedWrap())
 463       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 464     if (OBO->hasNoUnsignedWrap())
 465       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 466   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 467     if (Div->isExact())
 468       Flags |= 1 << bitc::SDIV_EXACT;
 469   }
 470
 471   return Flags;
 472 }
 473
 474 static void WriteMDNode(const MDNode *N,
 475                         const ValueEnumerator &VE,
 476                         BitstreamWriter &Stream,
 477                         SmallVector<uint64_t, 64> &Record) {
 478   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 479     if (N->getOperand(i)) {
 480       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 481       Record.push_back(VE.getValueID(N->getOperand(i)));
 482     } else {
 483       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 484       Record.push_back(0);
 485     }
 486   }
 487   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 488                                            bitc::METADATA_NODE;
 489   Stream.EmitRecord(MDCode, Record, 0);
 490   Record.clear();
 491 }
 492
 493 static void WriteModuleMetadata(const ValueEnumerator &VE,
 494                                 BitstreamWriter &Stream) {
 495   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 496   bool StartedMetadataBlock = false;
 497   unsigned MDSAbbrev = 0;
 498   SmallVector<uint64_t, 64> Record;
 499   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 500
 501     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 502       if (!N->isFunctionLocal()) {
 503         if (!StartedMetadataBlock) {
 504           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 505           StartedMetadataBlock = true;
 506         }
 507         WriteMDNode(N, VE, Stream, Record);
 508       }
 509     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 510       if (!StartedMetadataBlock)  {
 511         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 512
 513         // Abbrev for METADATA_STRING.
 514         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 515         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 516         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 517         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 518         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 519         StartedMetadataBlock = true;
 520       }
 521
 522       // Code: [strchar x N]
 523       Record.append(MDS->begin(), MDS->end());
 524
 525       // Emit the finished record.
 526       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 527       Record.clear();
 528     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 529       if (!StartedMetadataBlock)  {
 530         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 531         StartedMetadataBlock = true;
 532       }
 533
 534       // Write name.
 535       StringRef Str = NMD->getName();
 536       for (unsigned i = 0, e = Str.size(); i != e; ++i)
 537         Record.push_back(Str[i]);
 538       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 539       Record.clear();
 540
 541       // Write named metadata operands.
 542       for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
 543         if (NMD->getOperand(i))
 544           Record.push_back(VE.getValueID(NMD->getOperand(i)));
 545         else
 546           Record.push_back(~0U);
 547       }
 548       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 549       Record.clear();
 550     }
 551   }
 552
 553   if (StartedMetadataBlock)
 554     Stream.ExitBlock();
 555 }
 556
 557 static void WriteFunctionLocalMetadata(const ValueEnumerator &VE,
 558                                        BitstreamWriter &Stream) {
 559   bool StartedMetadataBlock = false;
 560   SmallVector<uint64_t, 64> Record;
 561   ValueEnumerator::ValueList Vals = VE.getMDValues();
 562   ValueEnumerator::ValueList::iterator it = Vals.begin();
 563   ValueEnumerator::ValueList::iterator end = Vals.end();
 564
 565   while (it != end) {
 566     if (const MDNode *N = dyn_cast<MDNode>((*it).first)) {
 567       if (N->isFunctionLocal()) {
 568         if (!StartedMetadataBlock) {
 569           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 570           StartedMetadataBlock = true;
 571         }
 572         WriteMDNode(N, VE, Stream, Record);
 573         // Remove function-local MD, since it is not used outside of function.
 574         it = Vals.erase(it);
 575         end = Vals.end();
 576         continue;
 577       }
 578     }
 579     ++it;
 580   }
 581
 582   if (StartedMetadataBlock)
 583     Stream.ExitBlock();
 584 }
 585
 586 static void WriteMetadataAttachment(const Function &F,
 587                                     const ValueEnumerator &VE,
 588                                     BitstreamWriter &Stream) {
 589   bool StartedMetadataBlock = false;
 590   SmallVector<uint64_t, 64> Record;
 591
 592   // Write metadata attachments
 593   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 594   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 595
 596   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 597     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 598          I != E; ++I) {
 599       MDs.clear();
 600       I->getAllMetadata(MDs);
 601
 602       // If no metadata, ignore instruction.
 603       if (MDs.empty()) continue;
 604
 605       Record.push_back(VE.getInstructionID(I));
 606
 607       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 608         Record.push_back(MDs[i].first);
 609         Record.push_back(VE.getValueID(MDs[i].second));
 610       }
 611       if (!StartedMetadataBlock)  {
 612         Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 613         StartedMetadataBlock = true;
 614       }
 615       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 616       Record.clear();
 617     }
 618
 619   if (StartedMetadataBlock)
 620     Stream.ExitBlock();
 621 }
 622
 623 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 624   SmallVector<uint64_t, 64> Record;
 625
 626   // Write metadata kinds
 627   // METADATA_KIND - [n x [id, name]]
 628   SmallVector<StringRef, 4> Names;
 629   M->getMDKindNames(Names);
 630
 631   assert(Names[0] == "" && "MDKind #0 is invalid");
 632   if (Names.size() == 1) return;
 633
 634   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 635
 636   for (unsigned MDKindID = 1, e = Names.size(); MDKindID != e; ++MDKindID) {
 637     Record.push_back(MDKindID);
 638     StringRef KName = Names[MDKindID];
 639     Record.append(KName.begin(), KName.end());
 640
 641     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 642     Record.clear();
 643   }
 644
 645   Stream.ExitBlock();
 646 }
 647
 648 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 649                            const ValueEnumerator &VE,
 650                            BitstreamWriter &Stream, bool isGlobal) {
 651   if (FirstVal == LastVal) return;
 652
 653   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 654
 655   unsigned AggregateAbbrev = 0;
 656   unsigned String8Abbrev = 0;
 657   unsigned CString7Abbrev = 0;
 658   unsigned CString6Abbrev = 0;
 659   // If this is a constant pool for the module, emit module-specific abbrevs.
 660   if (isGlobal) {
 661     // Abbrev for CST_CODE_AGGREGATE.
 662     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 663     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 666     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 667
 668     // Abbrev for CST_CODE_STRING.
 669     Abbv = new BitCodeAbbrev();
 670     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 673     String8Abbrev = Stream.EmitAbbrev(Abbv);
 674     // Abbrev for CST_CODE_CSTRING.
 675     Abbv = new BitCodeAbbrev();
 676     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 679     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 680     // Abbrev for CST_CODE_CSTRING.
 681     Abbv = new BitCodeAbbrev();
 682     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 683     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 684     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 685     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 686   }
 687
 688   SmallVector<uint64_t, 64> Record;
 689
 690   const ValueEnumerator::ValueList &Vals = VE.getValues();
 691   const Type *LastTy = 0;
 692   for (unsigned i = FirstVal; i != LastVal; ++i) {
 693     const Value *V = Vals[i].first;
 694     // If we need to switch types, do so now.
 695     if (V->getType() != LastTy) {
 696       LastTy = V->getType();
 697       Record.push_back(VE.getTypeID(LastTy));
 698       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 699                         CONSTANTS_SETTYPE_ABBREV);
 700       Record.clear();
 701     }
 702
 703     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 704       Record.push_back(unsigned(IA->hasSideEffects()) |
 705                        unsigned(IA->isAlignStack()) << 1);
 706
 707       // Add the asm string.
 708       const std::string &AsmStr = IA->getAsmString();
 709       Record.push_back(AsmStr.size());
 710       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 711         Record.push_back(AsmStr[i]);
 712
 713       // Add the constraint string.
 714       const std::string &ConstraintStr = IA->getConstraintString();
 715       Record.push_back(ConstraintStr.size());
 716       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 717         Record.push_back(ConstraintStr[i]);
 718       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 719       Record.clear();
 720       continue;
 721     }
 722     const Constant *C = cast<Constant>(V);
 723     unsigned Code = -1U;
 724     unsigned AbbrevToUse = 0;
 725     if (C->isNullValue()) {
 726       Code = bitc::CST_CODE_NULL;
 727     } else if (isa<UndefValue>(C)) {
 728       Code = bitc::CST_CODE_UNDEF;
 729     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 730       if (IV->getBitWidth() <= 64) {
 731         int64_t V = IV->getSExtValue();
 732         if (V >= 0)
 733           Record.push_back(V << 1);
 734         else
 735           Record.push_back((-V << 1) | 1);
 736         Code = bitc::CST_CODE_INTEGER;
 737         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 738       } else {                             // Wide integers, > 64 bits in size.
 739         // We have an arbitrary precision integer value to write whose
 740         // bit width is > 64. However, in canonical unsigned integer
 741         // format it is likely that the high bits are going to be zero.
 742         // So, we only write the number of active words.
 743         unsigned NWords = IV->getValue().getActiveWords();
 744         const uint64_t *RawWords = IV->getValue().getRawData();
 745         for (unsigned i = 0; i != NWords; ++i) {
 746           int64_t V = RawWords[i];
 747           if (V >= 0)
 748             Record.push_back(V << 1);
 749           else
 750             Record.push_back((-V << 1) | 1);
 751         }
 752         Code = bitc::CST_CODE_WIDE_INTEGER;
 753       }
 754     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 755       Code = bitc::CST_CODE_FLOAT;
 756       const Type *Ty = CFP->getType();
 757       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 758         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 759       } else if (Ty->isX86_FP80Ty()) {
 760         // api needed to prevent premature destruction
 761         // bits are not in the same order as a normal i80 APInt, compensate.
 762         APInt api = CFP->getValueAPF().bitcastToAPInt();
 763         const uint64_t *p = api.getRawData();
 764         Record.push_back((p[1] << 48) | (p[0] >> 16));
 765         Record.push_back(p[0] & 0xffffLL);
 766       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 767         APInt api = CFP->getValueAPF().bitcastToAPInt();
 768         const uint64_t *p = api.getRawData();
 769         Record.push_back(p[0]);
 770         Record.push_back(p[1]);
 771       } else {
 772         assert (0 && "Unknown FP type!");
 773       }
 774     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 775       const ConstantArray *CA = cast<ConstantArray>(C);
 776       // Emit constant strings specially.
 777       unsigned NumOps = CA->getNumOperands();
 778       // If this is a null-terminated string, use the denser CSTRING encoding.
 779       if (CA->getOperand(NumOps-1)->isNullValue()) {
 780         Code = bitc::CST_CODE_CSTRING;
 781         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 782       } else {
 783         Code = bitc::CST_CODE_STRING;
 784         AbbrevToUse = String8Abbrev;
 785       }
 786       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 787       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 788       for (unsigned i = 0; i != NumOps; ++i) {
 789         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 790         Record.push_back(V);
 791         isCStr7 &= (V & 128) == 0;
 792         if (isCStrChar6)
 793           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 794       }
 795
 796       if (isCStrChar6)
 797         AbbrevToUse = CString6Abbrev;
 798       else if (isCStr7)
 799         AbbrevToUse = CString7Abbrev;
 800     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 801                isa<ConstantVector>(V)) {
 802       Code = bitc::CST_CODE_AGGREGATE;
 803       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 804         Record.push_back(VE.getValueID(C->getOperand(i)));
 805       AbbrevToUse = AggregateAbbrev;
 806     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 807       switch (CE->getOpcode()) {
 808       default:
 809         if (Instruction::isCast(CE->getOpcode())) {
 810           Code = bitc::CST_CODE_CE_CAST;
 811           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 812           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 813           Record.push_back(VE.getValueID(C->getOperand(0)));
 814           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 815         } else {
 816           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 817           Code = bitc::CST_CODE_CE_BINOP;
 818           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 819           Record.push_back(VE.getValueID(C->getOperand(0)));
 820           Record.push_back(VE.getValueID(C->getOperand(1)));
 821           uint64_t Flags = GetOptimizationFlags(CE);
 822           if (Flags != 0)
 823             Record.push_back(Flags);
 824         }
 825         break;
 826       case Instruction::GetElementPtr:
 827         Code = bitc::CST_CODE_CE_GEP;
 828         if (cast<GEPOperator>(C)->isInBounds())
 829           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 830         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 831           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 832           Record.push_back(VE.getValueID(C->getOperand(i)));
 833         }
 834         break;
 835       case Instruction::Select:
 836         Code = bitc::CST_CODE_CE_SELECT;
 837         Record.push_back(VE.getValueID(C->getOperand(0)));
 838         Record.push_back(VE.getValueID(C->getOperand(1)));
 839         Record.push_back(VE.getValueID(C->getOperand(2)));
 840         break;
 841       case Instruction::ExtractElement:
 842         Code = bitc::CST_CODE_CE_EXTRACTELT;
 843         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 844         Record.push_back(VE.getValueID(C->getOperand(0)));
 845         Record.push_back(VE.getValueID(C->getOperand(1)));
 846         break;
 847       case Instruction::InsertElement:
 848         Code = bitc::CST_CODE_CE_INSERTELT;
 849         Record.push_back(VE.getValueID(C->getOperand(0)));
 850         Record.push_back(VE.getValueID(C->getOperand(1)));
 851         Record.push_back(VE.getValueID(C->getOperand(2)));
 852         break;
 853       case Instruction::ShuffleVector:
 854         // If the return type and argument types are the same, this is a
 855         // standard shufflevector instruction.  If the types are different,
 856         // then the shuffle is widening or truncating the input vectors, and
 857         // the argument type must also be encoded.
 858         if (C->getType() == C->getOperand(0)->getType()) {
 859           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 860         } else {
 861           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 862           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 863         }
 864         Record.push_back(VE.getValueID(C->getOperand(0)));
 865         Record.push_back(VE.getValueID(C->getOperand(1)));
 866         Record.push_back(VE.getValueID(C->getOperand(2)));
 867         break;
 868       case Instruction::ICmp:
 869       case Instruction::FCmp:
 870         Code = bitc::CST_CODE_CE_CMP;
 871         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 872         Record.push_back(VE.getValueID(C->getOperand(0)));
 873         Record.push_back(VE.getValueID(C->getOperand(1)));
 874         Record.push_back(CE->getPredicate());
 875         break;
 876       }
 877     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 878       assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
 879              "Malformed blockaddress");
 880       Code = bitc::CST_CODE_BLOCKADDRESS;
 881       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 882       Record.push_back(VE.getValueID(BA->getFunction()));
 883       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 884     } else {
 885       llvm_unreachable("Unknown constant!");
 886     }
 887     Stream.EmitRecord(Code, Record, AbbrevToUse);
 888     Record.clear();
 889   }
 890
 891   Stream.ExitBlock();
 892 }
 893
 894 static void WriteModuleConstants(const ValueEnumerator &VE,
 895                                  BitstreamWriter &Stream) {
 896   const ValueEnumerator::ValueList &Vals = VE.getValues();
 897
 898   // Find the first constant to emit, which is the first non-globalvalue value.
 899   // We know globalvalues have been emitted by WriteModuleInfo.
 900   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 901     if (!isa<GlobalValue>(Vals[i].first)) {
 902       WriteConstants(i, Vals.size(), VE, Stream, true);
 903       return;
 904     }
 905   }
 906 }
 907
 908 /// PushValueAndType - The file has to encode both the value and type id for
 909 /// many values, because we need to know what type to create for forward
 910 /// references.  However, most operands are not forward references, so this type
 911 /// field is not needed.
 912 ///
 913 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 914 /// instruction ID, then it is a forward reference, and it also includes the
 915 /// type ID.
 916 static bool PushValueAndType(const Value *V, unsigned InstID,
 917                              SmallVector<unsigned, 64> &Vals,
 918                              ValueEnumerator &VE) {
 919   unsigned ValID = VE.getValueID(V);
 920   Vals.push_back(ValID);
 921   if (ValID >= InstID) {
 922     Vals.push_back(VE.getTypeID(V->getType()));
 923     return true;
 924   }
 925   return false;
 926 }
 927
 928 /// WriteInstruction - Emit an instruction to the specified stream.
 929 static void WriteInstruction(const Instruction &I, unsigned InstID,
 930                              ValueEnumerator &VE, BitstreamWriter &Stream,
 931                              SmallVector<unsigned, 64> &Vals) {
 932   unsigned Code = 0;
 933   unsigned AbbrevToUse = 0;
 934   VE.setInstructionID(&I);
 935   switch (I.getOpcode()) {
 936   default:
 937     if (Instruction::isCast(I.getOpcode())) {
 938       Code = bitc::FUNC_CODE_INST_CAST;
 939       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 940         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 941       Vals.push_back(VE.getTypeID(I.getType()));
 942       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 943     } else {
 944       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 945       Code = bitc::FUNC_CODE_INST_BINOP;
 946       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 947         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 948       Vals.push_back(VE.getValueID(I.getOperand(1)));
 949       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 950       uint64_t Flags = GetOptimizationFlags(&I);
 951       if (Flags != 0) {
 952         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 953           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 954         Vals.push_back(Flags);
 955       }
 956     }
 957     break;
 958
 959   case Instruction::GetElementPtr:
 960     Code = bitc::FUNC_CODE_INST_GEP;
 961     if (cast<GEPOperator>(&I)->isInBounds())
 962       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 963     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 964       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 965     break;
 966   case Instruction::ExtractValue: {
 967     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 968     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 969     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 970     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 971       Vals.push_back(*i);
 972     break;
 973   }
 974   case Instruction::InsertValue: {
 975     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 976     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 977     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 978     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 979     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 980       Vals.push_back(*i);
 981     break;
 982   }
 983   case Instruction::Select:
 984     Code = bitc::FUNC_CODE_INST_VSELECT;
 985     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 986     Vals.push_back(VE.getValueID(I.getOperand(2)));
 987     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 988     break;
 989   case Instruction::ExtractElement:
 990     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 991     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 992     Vals.push_back(VE.getValueID(I.getOperand(1)));
 993     break;
 994   case Instruction::InsertElement:
 995     Code = bitc::FUNC_CODE_INST_INSERTELT;
 996     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 997     Vals.push_back(VE.getValueID(I.getOperand(1)));
 998     Vals.push_back(VE.getValueID(I.getOperand(2)));
 999     break;
1000   case Instruction::ShuffleVector:
1001     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1002     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1003     Vals.push_back(VE.getValueID(I.getOperand(1)));
1004     Vals.push_back(VE.getValueID(I.getOperand(2)));
1005     break;
1006   case Instruction::ICmp:
1007   case Instruction::FCmp:
1008     // compare returning Int1Ty or vector of Int1Ty
1009     Code = bitc::FUNC_CODE_INST_CMP2;
1010     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1011     Vals.push_back(VE.getValueID(I.getOperand(1)));
1012     Vals.push_back(cast<CmpInst>(I).getPredicate());
1013     break;
1014
1015   case Instruction::Ret:
1016     {
1017       Code = bitc::FUNC_CODE_INST_RET;
1018       unsigned NumOperands = I.getNumOperands();
1019       if (NumOperands == 0)
1020         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1021       else if (NumOperands == 1) {
1022         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1023           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1024       } else {
1025         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1026           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1027       }
1028     }
1029     break;
1030   case Instruction::Br:
1031     {
1032       Code = bitc::FUNC_CODE_INST_BR;
1033       BranchInst &II = cast<BranchInst>(I);
1034       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1035       if (II.isConditional()) {
1036         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1037         Vals.push_back(VE.getValueID(II.getCondition()));
1038       }
1039     }
1040     break;
1041   case Instruction::Switch:
1042     Code = bitc::FUNC_CODE_INST_SWITCH;
1043     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1044     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1045       Vals.push_back(VE.getValueID(I.getOperand(i)));
1046     break;
1047   case Instruction::IndirectBr:
1048     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1049     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1050     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1051       Vals.push_back(VE.getValueID(I.getOperand(i)));
1052     break;
1053
1054   case Instruction::Invoke: {
1055     const InvokeInst *II = cast<InvokeInst>(&I);
1056     const Value *Callee(II->getCalledValue());
1057     const PointerType *PTy = cast<PointerType>(Callee->getType());
1058     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1059     Code = bitc::FUNC_CODE_INST_INVOKE;
1060
1061     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1062     Vals.push_back(II->getCallingConv());
1063     Vals.push_back(VE.getValueID(II->getNormalDest()));
1064     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1065     PushValueAndType(Callee, InstID, Vals, VE);
1066
1067     // Emit value #'s for the fixed parameters.
1068     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1069       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1070
1071     // Emit type/value pairs for varargs params.
1072     if (FTy->isVarArg()) {
1073       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1074            i != e; ++i)
1075         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1076     }
1077     break;
1078   }
1079   case Instruction::Unwind:
1080     Code = bitc::FUNC_CODE_INST_UNWIND;
1081     break;
1082   case Instruction::Unreachable:
1083     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1084     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1085     break;
1086
1087   case Instruction::PHI:
1088     Code = bitc::FUNC_CODE_INST_PHI;
1089     Vals.push_back(VE.getTypeID(I.getType()));
1090     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1091       Vals.push_back(VE.getValueID(I.getOperand(i)));
1092     break;
1093
1094   case Instruction::Alloca:
1095     Code = bitc::FUNC_CODE_INST_ALLOCA;
1096     Vals.push_back(VE.getTypeID(I.getType()));
1097     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1098     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1099     break;
1100
1101   case Instruction::Load:
1102     Code = bitc::FUNC_CODE_INST_LOAD;
1103     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1104       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1105
1106     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1107     Vals.push_back(cast<LoadInst>(I).isVolatile());
1108     break;
1109   case Instruction::Store:
1110     Code = bitc::FUNC_CODE_INST_STORE2;
1111     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1112     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1113     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1114     Vals.push_back(cast<StoreInst>(I).isVolatile());
1115     break;
1116   case Instruction::Call: {
1117     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1118     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1119
1120     Code = bitc::FUNC_CODE_INST_CALL;
1121
1122     const CallInst *CI = cast<CallInst>(&I);
1123     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1124     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1125     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1126
1127     // Emit value #'s for the fixed parameters.
1128     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1129       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1130
1131     // Emit type/value pairs for varargs params.
1132     if (FTy->isVarArg()) {
1133       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1134       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1135            i != e; ++i)
1136         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1137     }
1138     break;
1139   }
1140   case Instruction::VAArg:
1141     Code = bitc::FUNC_CODE_INST_VAARG;
1142     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1143     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1144     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1145     break;
1146   }
1147
1148   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1149   Vals.clear();
1150 }
1151
1152 // Emit names for globals/functions etc.
1153 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1154                                   const ValueEnumerator &VE,
1155                                   BitstreamWriter &Stream) {
1156   if (VST.empty()) return;
1157   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1158
1159   // FIXME: Set up the abbrev, we know how many values there are!
1160   // FIXME: We know if the type names can use 7-bit ascii.
1161   SmallVector<unsigned, 64> NameVals;
1162
1163   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1164        SI != SE; ++SI) {
1165
1166     const ValueName &Name = *SI;
1167
1168     // Figure out the encoding to use for the name.
1169     bool is7Bit = true;
1170     bool isChar6 = true;
1171     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1172          C != E; ++C) {
1173       if (isChar6)
1174         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1175       if ((unsigned char)*C & 128) {
1176         is7Bit = false;
1177         break;  // don't bother scanning the rest.
1178       }
1179     }
1180
1181     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1182
1183     // VST_ENTRY:   [valueid, namechar x N]
1184     // VST_BBENTRY: [bbid, namechar x N]
1185     unsigned Code;
1186     if (isa<BasicBlock>(SI->getValue())) {
1187       Code = bitc::VST_CODE_BBENTRY;
1188       if (isChar6)
1189         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1190     } else {
1191       Code = bitc::VST_CODE_ENTRY;
1192       if (isChar6)
1193         AbbrevToUse = VST_ENTRY_6_ABBREV;
1194       else if (is7Bit)
1195         AbbrevToUse = VST_ENTRY_7_ABBREV;
1196     }
1197
1198     NameVals.push_back(VE.getValueID(SI->getValue()));
1199     for (const char *P = Name.getKeyData(),
1200          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1201       NameVals.push_back((unsigned char)*P);
1202
1203     // Emit the finished record.
1204     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1205     NameVals.clear();
1206   }
1207   Stream.ExitBlock();
1208 }
1209
1210 /// WriteFunction - Emit a function body to the module stream.
1211 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1212                           BitstreamWriter &Stream) {
1213   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1214   VE.incorporateFunction(F);
1215
1216   SmallVector<unsigned, 64> Vals;
1217
1218   // Emit the number of basic blocks, so the reader can create them ahead of
1219   // time.
1220   Vals.push_back(VE.getBasicBlocks().size());
1221   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1222   Vals.clear();
1223
1224   // If there are function-local constants, emit them now.
1225   unsigned CstStart, CstEnd;
1226   VE.getFunctionConstantRange(CstStart, CstEnd);
1227   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1228
1229   // Keep a running idea of what the instruction ID is.
1230   unsigned InstID = CstEnd;
1231
1232   // Finally, emit all the instructions, in order.
1233   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1234     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1235          I != E; ++I) {
1236       WriteInstruction(*I, InstID, VE, Stream, Vals);
1237       if (!I->getType()->isVoidTy())
1238         ++InstID;
1239     }
1240
1241   // Emit names for all the instructions etc.
1242   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1243
1244   WriteFunctionLocalMetadata(VE, Stream);
1245   WriteMetadataAttachment(F, VE, Stream);
1246   VE.purgeFunction();
1247   Stream.ExitBlock();
1248 }
1249
1250 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1251 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1252                                  const ValueEnumerator &VE,
1253                                  BitstreamWriter &Stream) {
1254   if (TST.empty()) return;
1255
1256   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1257
1258   // 7-bit fixed width VST_CODE_ENTRY strings.
1259   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1260   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1261   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1262                             Log2_32_Ceil(VE.getTypes().size()+1)));
1263   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1264   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1265   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1266
1267   SmallVector<unsigned, 64> NameVals;
1268
1269   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1270        TI != TE; ++TI) {
1271     // TST_ENTRY: [typeid, namechar x N]
1272     NameVals.push_back(VE.getTypeID(TI->second));
1273
1274     const std::string &Str = TI->first;
1275     bool is7Bit = true;
1276     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1277       NameVals.push_back((unsigned char)Str[i]);
1278       if (Str[i] & 128)
1279         is7Bit = false;
1280     }
1281
1282     // Emit the finished record.
1283     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1284     NameVals.clear();
1285   }
1286
1287   Stream.ExitBlock();
1288 }
1289
1290 // Emit blockinfo, which defines the standard abbreviations etc.
1291 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1292   // We only want to emit block info records for blocks that have multiple
1293   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1294   // blocks can defined their abbrevs inline.
1295   Stream.EnterBlockInfoBlock(2);
1296
1297   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1298     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1303     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1304                                    Abbv) != VST_ENTRY_8_ABBREV)
1305       llvm_unreachable("Unexpected abbrev ordering!");
1306   }
1307
1308   { // 7-bit fixed width VST_ENTRY strings.
1309     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1310     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1313     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1314     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1315                                    Abbv) != VST_ENTRY_7_ABBREV)
1316       llvm_unreachable("Unexpected abbrev ordering!");
1317   }
1318   { // 6-bit char6 VST_ENTRY strings.
1319     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1320     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1324     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1325                                    Abbv) != VST_ENTRY_6_ABBREV)
1326       llvm_unreachable("Unexpected abbrev ordering!");
1327   }
1328   { // 6-bit char6 VST_BBENTRY strings.
1329     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1330     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1334     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1335                                    Abbv) != VST_BBENTRY_6_ABBREV)
1336       llvm_unreachable("Unexpected abbrev ordering!");
1337   }
1338
1339
1340
1341   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1342     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1343     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1345                               Log2_32_Ceil(VE.getTypes().size()+1)));
1346     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1347                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1348       llvm_unreachable("Unexpected abbrev ordering!");
1349   }
1350
1351   { // INTEGER abbrev for CONSTANTS_BLOCK.
1352     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1353     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1355     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1356                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1357       llvm_unreachable("Unexpected abbrev ordering!");
1358   }
1359
1360   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1361     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1362     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1365                               Log2_32_Ceil(VE.getTypes().size()+1)));
1366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1367
1368     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1369                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1370       llvm_unreachable("Unexpected abbrev ordering!");
1371   }
1372   { // NULL abbrev for CONSTANTS_BLOCK.
1373     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1374     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1375     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1376                                    Abbv) != CONSTANTS_NULL_Abbrev)
1377       llvm_unreachable("Unexpected abbrev ordering!");
1378   }
1379
1380   // FIXME: This should only use space for first class types!
1381
1382   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1383     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1384     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1387     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1388     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1389                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1390       llvm_unreachable("Unexpected abbrev ordering!");
1391   }
1392   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1393     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1394     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1398     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1399                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1400       llvm_unreachable("Unexpected abbrev ordering!");
1401   }
1402   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1403     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1404     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1409     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1410                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1411       llvm_unreachable("Unexpected abbrev ordering!");
1412   }
1413   { // INST_CAST abbrev for FUNCTION_BLOCK.
1414     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1415     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1418                               Log2_32_Ceil(VE.getTypes().size()+1)));
1419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1420     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1421                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1422       llvm_unreachable("Unexpected abbrev ordering!");
1423   }
1424
1425   { // INST_RET abbrev for FUNCTION_BLOCK.
1426     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1427     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1428     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1429                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1430       llvm_unreachable("Unexpected abbrev ordering!");
1431   }
1432   { // INST_RET abbrev for FUNCTION_BLOCK.
1433     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1434     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1436     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1437                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1438       llvm_unreachable("Unexpected abbrev ordering!");
1439   }
1440   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1441     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1442     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1443     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1444                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1445       llvm_unreachable("Unexpected abbrev ordering!");
1446   }
1447
1448   Stream.ExitBlock();
1449 }
1450
1451
1452 /// WriteModule - Emit the specified module to the bitstream.
1453 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1454   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1455
1456   // Emit the version number if it is non-zero.
1457   if (CurVersion) {
1458     SmallVector<unsigned, 1> Vals;
1459     Vals.push_back(CurVersion);
1460     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1461   }
1462
1463   // Analyze the module, enumerating globals, functions, etc.
1464   ValueEnumerator VE(M);
1465
1466   // Emit blockinfo, which defines the standard abbreviations etc.
1467   WriteBlockInfo(VE, Stream);
1468
1469   // Emit information about parameter attributes.
1470   WriteAttributeTable(VE, Stream);
1471
1472   // Emit information describing all of the types in the module.
1473   WriteTypeTable(VE, Stream);
1474
1475   // Emit top-level description of module, including target triple, inline asm,
1476   // descriptors for global variables, and function prototype info.
1477   WriteModuleInfo(M, VE, Stream);
1478
1479   // Emit constants.
1480   WriteModuleConstants(VE, Stream);
1481
1482   // Emit metadata.
1483   WriteModuleMetadata(VE, Stream);
1484
1485   // Emit function bodies.
1486   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1487     if (!I->isDeclaration())
1488       WriteFunction(*I, VE, Stream);
1489
1490   // Emit metadata.
1491   WriteModuleMetadataStore(M, Stream);
1492
1493   // Emit the type symbol table information.
1494   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1495
1496   // Emit names for globals/functions etc.
1497   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1498
1499   Stream.ExitBlock();
1500 }
1501
1502 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1503 /// header and trailer to make it compatible with the system archiver.  To do
1504 /// this we emit the following header, and then emit a trailer that pads the
1505 /// file out to be a multiple of 16 bytes.
1506 ///
1507 /// struct bc_header {
1508 ///   uint32_t Magic;         // 0x0B17C0DE
1509 ///   uint32_t Version;       // Version, currently always 0.
1510 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1511 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1512 ///   uint32_t CPUType;       // CPU specifier.
1513 ///   ... potentially more later ...
1514 /// };
1515 enum {
1516   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1517   DarwinBCHeaderSize = 5*4
1518 };
1519
1520 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1521                                const std::string &TT) {
1522   unsigned CPUType = ~0U;
1523
1524   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1525   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1526   // specific constants here because they are implicitly part of the Darwin ABI.
1527   enum {
1528     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1529     DARWIN_CPU_TYPE_X86        = 7,
1530     DARWIN_CPU_TYPE_POWERPC    = 18
1531   };
1532
1533   if (TT.find("x86_64-") == 0)
1534     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1535   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1536            TT[4] == '-' && TT[1] - '3' < 6)
1537     CPUType = DARWIN_CPU_TYPE_X86;
1538   else if (TT.find("powerpc-") == 0)
1539     CPUType = DARWIN_CPU_TYPE_POWERPC;
1540   else if (TT.find("powerpc64-") == 0)
1541     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1542
1543   // Traditional Bitcode starts after header.
1544   unsigned BCOffset = DarwinBCHeaderSize;
1545
1546   Stream.Emit(0x0B17C0DE, 32);
1547   Stream.Emit(0         , 32);  // Version.
1548   Stream.Emit(BCOffset  , 32);
1549   Stream.Emit(0         , 32);  // Filled in later.
1550   Stream.Emit(CPUType   , 32);
1551 }
1552
1553 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1554 /// finalize the header.
1555 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1556   // Update the size field in the header.
1557   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1558
1559   // If the file is not a multiple of 16 bytes, insert dummy padding.
1560   while (BufferSize & 15) {
1561     Stream.Emit(0, 8);
1562     ++BufferSize;
1563   }
1564 }
1565
1566
1567 /// WriteBitcodeToFile - Write the specified module to the specified output
1568 /// stream.
1569 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1570   std::vector<unsigned char> Buffer;
1571   BitstreamWriter Stream(Buffer);
1572
1573   Buffer.reserve(256*1024);
1574
1575   WriteBitcodeToStream( M, Stream );
1576
1577   // If writing to stdout, set binary mode.
1578   if (&llvm::outs() == &Out)
1579     sys::Program::ChangeStdoutToBinary();
1580
1581   // Write the generated bitstream to "Out".
1582   Out.write((char*)&Buffer.front(), Buffer.size());
1583
1584   // Make sure it hits disk now.
1585   Out.flush();
1586 }
1587
1588 /// WriteBitcodeToStream - Write the specified module to the specified output
1589 /// stream.
1590 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1591   // If this is darwin, emit a file header and trailer if needed.
1592   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1593   if (isDarwin)
1594     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1595
1596   // Emit the file header.
1597   Stream.Emit((unsigned)'B', 8);
1598   Stream.Emit((unsigned)'C', 8);
1599   Stream.Emit(0x0, 4);
1600   Stream.Emit(0xC, 4);
1601   Stream.Emit(0xE, 4);
1602   Stream.Emit(0xD, 4);
1603
1604   // Emit the module.
1605   WriteModule(M, Stream);
1606
1607   if (isDarwin)
1608     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1609 }