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/LLVMContext.h"
  23 #include "llvm/Metadata.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/Operator.h"
  26 #include "llvm/TypeSymbolTable.h"
  27 #include "llvm/ValueSymbolTable.h"
  28 #include "llvm/Support/ErrorHandling.h"
  29 #include "llvm/Support/MathExtras.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include "llvm/System/Program.h"
  32 using namespace llvm;
  33
  34 /// These are manifest constants used by the bitcode writer. They do not need to
  35 /// be kept in sync with the reader, but need to be consistent within this file.
  36 enum {
  37   CurVersion = 0,
  38
  39   // VALUE_SYMTAB_BLOCK abbrev id's.
  40   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  41   VST_ENTRY_7_ABBREV,
  42   VST_ENTRY_6_ABBREV,
  43   VST_BBENTRY_6_ABBREV,
  44
  45   // CONSTANTS_BLOCK abbrev id's.
  46   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  47   CONSTANTS_INTEGER_ABBREV,
  48   CONSTANTS_CE_CAST_Abbrev,
  49   CONSTANTS_NULL_Abbrev,
  50
  51   // FUNCTION_BLOCK abbrev id's.
  52   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  53   FUNCTION_INST_BINOP_ABBREV,
  54   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  55   FUNCTION_INST_CAST_ABBREV,
  56   FUNCTION_INST_RET_VOID_ABBREV,
  57   FUNCTION_INST_RET_VAL_ABBREV,
  58   FUNCTION_INST_UNREACHABLE_ABBREV
  59 };
  60
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   }
  78 }
  79
  80 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  81   switch (Opcode) {
  82   default: llvm_unreachable("Unknown binary instruction!");
  83   case Instruction::Add:
  84   case Instruction::FAdd: return bitc::BINOP_ADD;
  85   case Instruction::Sub:
  86   case Instruction::FSub: return bitc::BINOP_SUB;
  87   case Instruction::Mul:
  88   case Instruction::FMul: return bitc::BINOP_MUL;
  89   case Instruction::UDiv: return bitc::BINOP_UDIV;
  90   case Instruction::FDiv:
  91   case Instruction::SDiv: return bitc::BINOP_SDIV;
  92   case Instruction::URem: return bitc::BINOP_UREM;
  93   case Instruction::FRem:
  94   case Instruction::SRem: return bitc::BINOP_SREM;
  95   case Instruction::Shl:  return bitc::BINOP_SHL;
  96   case Instruction::LShr: return bitc::BINOP_LSHR;
  97   case Instruction::AShr: return bitc::BINOP_ASHR;
  98   case Instruction::And:  return bitc::BINOP_AND;
  99   case Instruction::Or:   return bitc::BINOP_OR;
 100   case Instruction::Xor:  return bitc::BINOP_XOR;
 101   }
 102 }
 103
 104
 105
 106 static void WriteStringRecord(unsigned Code, const std::string &Str,
 107                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 108   SmallVector<unsigned, 64> Vals;
 109
 110   // Code: [strchar x N]
 111   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 112     Vals.push_back(Str[i]);
 113
 114   // Emit the finished record.
 115   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 116 }
 117
 118 // Emit information about parameter attributes.
 119 static void WriteAttributeTable(const ValueEnumerator &VE,
 120                                 BitstreamWriter &Stream) {
 121   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 122   if (Attrs.empty()) return;
 123
 124   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 125
 126   SmallVector<uint64_t, 64> Record;
 127   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 128     const AttrListPtr &A = Attrs[i];
 129     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 130       const AttributeWithIndex &PAWI = A.getSlot(i);
 131       Record.push_back(PAWI.Index);
 132
 133       // FIXME: remove in LLVM 3.0
 134       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 135       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 136       // 11 bits.
 137       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 138       if (PAWI.Attrs & Attribute::Alignment)
 139         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 140       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 141
 142       Record.push_back(FauxAttr);
 143     }
 144
 145     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 146     Record.clear();
 147   }
 148
 149   Stream.ExitBlock();
 150 }
 151
 152 /// WriteTypeTable - Write out the type table for a module.
 153 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 154   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 155
 156   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 157   SmallVector<uint64_t, 64> TypeVals;
 158
 159   // Abbrev for TYPE_CODE_POINTER.
 160   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 161   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 163                             Log2_32_Ceil(VE.getTypes().size()+1)));
 164   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 165   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 166
 167   // Abbrev for TYPE_CODE_FUNCTION.
 168   Abbv = new BitCodeAbbrev();
 169   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 171   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 174                             Log2_32_Ceil(VE.getTypes().size()+1)));
 175   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 176
 177   // Abbrev for TYPE_CODE_STRUCT.
 178   Abbv = new BitCodeAbbrev();
 179   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 183                             Log2_32_Ceil(VE.getTypes().size()+1)));
 184   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 185
 186   // Abbrev for TYPE_CODE_ARRAY.
 187   Abbv = new BitCodeAbbrev();
 188   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 191                             Log2_32_Ceil(VE.getTypes().size()+1)));
 192   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 193
 194   // Emit an entry count so the reader can reserve space.
 195   TypeVals.push_back(TypeList.size());
 196   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 197   TypeVals.clear();
 198
 199   // Loop over all of the types, emitting each in turn.
 200   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 201     const Type *T = TypeList[i].first;
 202     int AbbrevToUse = 0;
 203     unsigned Code = 0;
 204
 205     switch (T->getTypeID()) {
 206     default: llvm_unreachable("Unknown type!");
 207     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 208     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 209     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 210     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 211     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 212     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 213     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 214     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 215     case Type::MetadataTyID: Code = bitc::TYPE_CODE_METADATA; break;
 216     case Type::IntegerTyID:
 217       // INTEGER: [width]
 218       Code = bitc::TYPE_CODE_INTEGER;
 219       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 220       break;
 221     case Type::PointerTyID: {
 222       const PointerType *PTy = cast<PointerType>(T);
 223       // POINTER: [pointee type, address space]
 224       Code = bitc::TYPE_CODE_POINTER;
 225       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 226       unsigned AddressSpace = PTy->getAddressSpace();
 227       TypeVals.push_back(AddressSpace);
 228       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 229       break;
 230     }
 231     case Type::FunctionTyID: {
 232       const FunctionType *FT = cast<FunctionType>(T);
 233       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 234       Code = bitc::TYPE_CODE_FUNCTION;
 235       TypeVals.push_back(FT->isVarArg());
 236       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 237       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 238       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 239         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 240       AbbrevToUse = FunctionAbbrev;
 241       break;
 242     }
 243     case Type::StructTyID: {
 244       const StructType *ST = cast<StructType>(T);
 245       // STRUCT: [ispacked, eltty x N]
 246       Code = bitc::TYPE_CODE_STRUCT;
 247       TypeVals.push_back(ST->isPacked());
 248       // Output all of the element types.
 249       for (StructType::element_iterator I = ST->element_begin(),
 250            E = ST->element_end(); I != E; ++I)
 251         TypeVals.push_back(VE.getTypeID(*I));
 252       AbbrevToUse = StructAbbrev;
 253       break;
 254     }
 255     case Type::ArrayTyID: {
 256       const ArrayType *AT = cast<ArrayType>(T);
 257       // ARRAY: [numelts, eltty]
 258       Code = bitc::TYPE_CODE_ARRAY;
 259       TypeVals.push_back(AT->getNumElements());
 260       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 261       AbbrevToUse = ArrayAbbrev;
 262       break;
 263     }
 264     case Type::VectorTyID: {
 265       const VectorType *VT = cast<VectorType>(T);
 266       // VECTOR [numelts, eltty]
 267       Code = bitc::TYPE_CODE_VECTOR;
 268       TypeVals.push_back(VT->getNumElements());
 269       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 270       break;
 271     }
 272     }
 273
 274     // Emit the finished record.
 275     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 276     TypeVals.clear();
 277   }
 278
 279   Stream.ExitBlock();
 280 }
 281
 282 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 283   switch (GV->getLinkage()) {
 284   default: llvm_unreachable("Invalid linkage!");
 285   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 286   case GlobalValue::ExternalLinkage:            return 0;
 287   case GlobalValue::WeakAnyLinkage:             return 1;
 288   case GlobalValue::AppendingLinkage:           return 2;
 289   case GlobalValue::InternalLinkage:            return 3;
 290   case GlobalValue::LinkOnceAnyLinkage:         return 4;
 291   case GlobalValue::DLLImportLinkage:           return 5;
 292   case GlobalValue::DLLExportLinkage:           return 6;
 293   case GlobalValue::ExternalWeakLinkage:        return 7;
 294   case GlobalValue::CommonLinkage:              return 8;
 295   case GlobalValue::PrivateLinkage:             return 9;
 296   case GlobalValue::WeakODRLinkage:             return 10;
 297   case GlobalValue::LinkOnceODRLinkage:         return 11;
 298   case GlobalValue::AvailableExternallyLinkage: return 12;
 299   case GlobalValue::LinkerPrivateLinkage:       return 13;
 300   }
 301 }
 302
 303 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 304   switch (GV->getVisibility()) {
 305   default: llvm_unreachable("Invalid visibility!");
 306   case GlobalValue::DefaultVisibility:   return 0;
 307   case GlobalValue::HiddenVisibility:    return 1;
 308   case GlobalValue::ProtectedVisibility: return 2;
 309   }
 310 }
 311
 312 // Emit top-level description of module, including target triple, inline asm,
 313 // descriptors for global variables, and function prototype info.
 314 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 315                             BitstreamWriter &Stream) {
 316   // Emit the list of dependent libraries for the Module.
 317   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 318     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 319
 320   // Emit various pieces of data attached to a module.
 321   if (!M->getTargetTriple().empty())
 322     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 323                       0/*TODO*/, Stream);
 324   if (!M->getDataLayout().empty())
 325     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 326                       0/*TODO*/, Stream);
 327   if (!M->getModuleInlineAsm().empty())
 328     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 329                       0/*TODO*/, Stream);
 330
 331   // Emit information about sections and GC, computing how many there are. Also
 332   // compute the maximum alignment value.
 333   std::map<std::string, unsigned> SectionMap;
 334   std::map<std::string, unsigned> GCMap;
 335   unsigned MaxAlignment = 0;
 336   unsigned MaxGlobalType = 0;
 337   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 338        GV != E; ++GV) {
 339     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 340     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 341
 342     if (!GV->hasSection()) continue;
 343     // Give section names unique ID's.
 344     unsigned &Entry = SectionMap[GV->getSection()];
 345     if (Entry != 0) continue;
 346     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 347                       0/*TODO*/, Stream);
 348     Entry = SectionMap.size();
 349   }
 350   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 351     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 352     if (F->hasSection()) {
 353       // Give section names unique ID's.
 354       unsigned &Entry = SectionMap[F->getSection()];
 355       if (!Entry) {
 356         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 357                           0/*TODO*/, Stream);
 358         Entry = SectionMap.size();
 359       }
 360     }
 361     if (F->hasGC()) {
 362       // Same for GC names.
 363       unsigned &Entry = GCMap[F->getGC()];
 364       if (!Entry) {
 365         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 366                           0/*TODO*/, Stream);
 367         Entry = GCMap.size();
 368       }
 369     }
 370   }
 371
 372   // Emit abbrev for globals, now that we know # sections and max alignment.
 373   unsigned SimpleGVarAbbrev = 0;
 374   if (!M->global_empty()) {
 375     // Add an abbrev for common globals with no visibility or thread localness.
 376     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 377     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 379                               Log2_32_Ceil(MaxGlobalType+1)));
 380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 383     if (MaxAlignment == 0)                                      // Alignment.
 384       Abbv->Add(BitCodeAbbrevOp(0));
 385     else {
 386       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 387       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 388                                Log2_32_Ceil(MaxEncAlignment+1)));
 389     }
 390     if (SectionMap.empty())                                    // Section.
 391       Abbv->Add(BitCodeAbbrevOp(0));
 392     else
 393       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 394                                Log2_32_Ceil(SectionMap.size()+1)));
 395     // Don't bother emitting vis + thread local.
 396     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 397   }
 398
 399   // Emit the global variable information.
 400   SmallVector<unsigned, 64> Vals;
 401   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 402        GV != E; ++GV) {
 403     unsigned AbbrevToUse = 0;
 404
 405     // GLOBALVAR: [type, isconst, initid,
 406     //             linkage, alignment, section, visibility, threadlocal]
 407     Vals.push_back(VE.getTypeID(GV->getType()));
 408     Vals.push_back(GV->isConstant());
 409     Vals.push_back(GV->isDeclaration() ? 0 :
 410                    (VE.getValueID(GV->getInitializer()) + 1));
 411     Vals.push_back(getEncodedLinkage(GV));
 412     Vals.push_back(Log2_32(GV->getAlignment())+1);
 413     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 414     if (GV->isThreadLocal() ||
 415         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 416       Vals.push_back(getEncodedVisibility(GV));
 417       Vals.push_back(GV->isThreadLocal());
 418     } else {
 419       AbbrevToUse = SimpleGVarAbbrev;
 420     }
 421
 422     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 423     Vals.clear();
 424   }
 425
 426   // Emit the function proto information.
 427   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 428     // FUNCTION:  [type, callingconv, isproto, paramattr,
 429     //             linkage, alignment, section, visibility, gc]
 430     Vals.push_back(VE.getTypeID(F->getType()));
 431     Vals.push_back(F->getCallingConv());
 432     Vals.push_back(F->isDeclaration());
 433     Vals.push_back(getEncodedLinkage(F));
 434     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 435     Vals.push_back(Log2_32(F->getAlignment())+1);
 436     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 437     Vals.push_back(getEncodedVisibility(F));
 438     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 439
 440     unsigned AbbrevToUse = 0;
 441     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 442     Vals.clear();
 443   }
 444
 445
 446   // Emit the alias information.
 447   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 448        AI != E; ++AI) {
 449     Vals.push_back(VE.getTypeID(AI->getType()));
 450     Vals.push_back(VE.getValueID(AI->getAliasee()));
 451     Vals.push_back(getEncodedLinkage(AI));
 452     Vals.push_back(getEncodedVisibility(AI));
 453     unsigned AbbrevToUse = 0;
 454     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 455     Vals.clear();
 456   }
 457 }
 458
 459 static uint64_t GetOptimizationFlags(const Value *V) {
 460   uint64_t Flags = 0;
 461
 462   if (const OverflowingBinaryOperator *OBO =
 463         dyn_cast<OverflowingBinaryOperator>(V)) {
 464     if (OBO->hasNoSignedWrap())
 465       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 466     if (OBO->hasNoUnsignedWrap())
 467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 468   } else if (const SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
 469     if (Div->isExact())
 470       Flags |= 1 << bitc::SDIV_EXACT;
 471   }
 472
 473   return Flags;
 474 }
 475
 476 static void WriteMDNode(const MDNode *N,
 477                         const ValueEnumerator &VE,
 478                         BitstreamWriter &Stream,
 479                         SmallVector<uint64_t, 64> &Record) {
 480   for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 481     if (N->getElement(i)) {
 482       Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 483       Record.push_back(VE.getValueID(N->getElement(i)));
 484     } else {
 485       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 486       Record.push_back(0);
 487     }
 488   }
 489   Stream.EmitRecord(bitc::METADATA_NODE, 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 (!StartedMetadataBlock) {
 503         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 504         StartedMetadataBlock = true;
 505       }
 506       WriteMDNode(N, VE, Stream, Record);
 507     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 508       if (!StartedMetadataBlock)  {
 509         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 510
 511         // Abbrev for METADATA_STRING.
 512         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 513         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 514         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 515         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 516         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 517         StartedMetadataBlock = true;
 518       }
 519
 520       // Code: [strchar x N]
 521       Record.append(MDS->begin(), MDS->end());
 522
 523       // Emit the finished record.
 524       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 525       Record.clear();
 526     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(Vals[i].first)) {
 527       if (!StartedMetadataBlock)  {
 528         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 529         StartedMetadataBlock = true;
 530       }
 531
 532       // Write name.
 533       std::string Str = NMD->getNameStr();
 534       const char *StrBegin = Str.c_str();
 535       for (unsigned i = 0, e = Str.length(); i != e; ++i)
 536         Record.push_back(StrBegin[i]);
 537       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 538       Record.clear();
 539
 540       // Write named metadata elements.
 541       for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
 542         if (NMD->getElement(i))
 543           Record.push_back(VE.getValueID(NMD->getElement(i)));
 544         else
 545           Record.push_back(0);
 546       }
 547       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 548       Record.clear();
 549     }
 550   }
 551
 552   if (StartedMetadataBlock)
 553     Stream.ExitBlock();
 554 }
 555
 556 static void WriteMetadataAttachment(const Function &F,
 557                                     const ValueEnumerator &VE,
 558                                     BitstreamWriter &Stream) {
 559   bool StartedMetadataBlock = false;
 560   SmallVector<uint64_t, 64> Record;
 561
 562   // Write metadata attachments
 563   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 564   MetadataContext &TheMetadata = F.getContext().getMetadata();
 565   typedef SmallVector<std::pair<unsigned, TrackingVH<MDNode> >, 2> MDMapTy;
 566   MDMapTy MDs;
 567   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 568     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 569          I != E; ++I) {
 570       MDs.clear();
 571       TheMetadata.getMDs(I, MDs);
 572       bool RecordedInstruction = false;
 573       for (MDMapTy::const_iterator PI = MDs.begin(), PE = MDs.end();
 574              PI != PE; ++PI) {
 575         if (RecordedInstruction == false) {
 576           Record.push_back(VE.getInstructionID(I));
 577           RecordedInstruction = true;
 578         }
 579         Record.push_back(PI->first);
 580         Record.push_back(VE.getValueID(PI->second));
 581       }
 582       if (!Record.empty()) {
 583         if (!StartedMetadataBlock)  {
 584           Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 585           StartedMetadataBlock = true;
 586         }
 587         Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 588         Record.clear();
 589       }
 590     }
 591
 592   if (StartedMetadataBlock)
 593     Stream.ExitBlock();
 594 }
 595
 596 static void WriteModuleMetadataStore(const Module *M,
 597                                      const ValueEnumerator &VE,
 598                                      BitstreamWriter &Stream) {
 599
 600   bool StartedMetadataBlock = false;
 601   SmallVector<uint64_t, 64> Record;
 602
 603   // Write metadata kinds
 604   // METADATA_KIND - [n x [id, name]]
 605   MetadataContext &TheMetadata = M->getContext().getMetadata();
 606   SmallVector<std::pair<unsigned, StringRef>, 4> Names;
 607   TheMetadata.getHandlerNames(Names);
 608   for (SmallVector<std::pair<unsigned, StringRef>, 4>::iterator
 609          I = Names.begin(),
 610          E = Names.end(); I != E; ++I) {
 611     Record.push_back(I->first);
 612     StringRef KName = I->second;
 613     for (unsigned i = 0, e = KName.size(); i != e; ++i)
 614       Record.push_back(KName[i]);
 615     if (!StartedMetadataBlock)  {
 616       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 617       StartedMetadataBlock = true;
 618     }
 619     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 620     Record.clear();
 621   }
 622
 623   if (StartedMetadataBlock)
 624     Stream.ExitBlock();
 625 }
 626
 627 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 628                            const ValueEnumerator &VE,
 629                            BitstreamWriter &Stream, bool isGlobal) {
 630   if (FirstVal == LastVal) return;
 631
 632   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 633
 634   unsigned AggregateAbbrev = 0;
 635   unsigned String8Abbrev = 0;
 636   unsigned CString7Abbrev = 0;
 637   unsigned CString6Abbrev = 0;
 638   // If this is a constant pool for the module, emit module-specific abbrevs.
 639   if (isGlobal) {
 640     // Abbrev for CST_CODE_AGGREGATE.
 641     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 642     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 645     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 646
 647     // Abbrev for CST_CODE_STRING.
 648     Abbv = new BitCodeAbbrev();
 649     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 650     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 652     String8Abbrev = Stream.EmitAbbrev(Abbv);
 653     // Abbrev for CST_CODE_CSTRING.
 654     Abbv = new BitCodeAbbrev();
 655     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 658     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 659     // Abbrev for CST_CODE_CSTRING.
 660     Abbv = new BitCodeAbbrev();
 661     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 664     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 665   }
 666
 667   SmallVector<uint64_t, 64> Record;
 668
 669   const ValueEnumerator::ValueList &Vals = VE.getValues();
 670   const Type *LastTy = 0;
 671   for (unsigned i = FirstVal; i != LastVal; ++i) {
 672     const Value *V = Vals[i].first;
 673     // If we need to switch types, do so now.
 674     if (V->getType() != LastTy) {
 675       LastTy = V->getType();
 676       Record.push_back(VE.getTypeID(LastTy));
 677       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 678                         CONSTANTS_SETTYPE_ABBREV);
 679       Record.clear();
 680     }
 681
 682     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 683       Record.push_back(unsigned(IA->hasSideEffects()) |
 684                        unsigned(IA->isAlignStack()) << 1);
 685
 686       // Add the asm string.
 687       const std::string &AsmStr = IA->getAsmString();
 688       Record.push_back(AsmStr.size());
 689       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 690         Record.push_back(AsmStr[i]);
 691
 692       // Add the constraint string.
 693       const std::string &ConstraintStr = IA->getConstraintString();
 694       Record.push_back(ConstraintStr.size());
 695       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 696         Record.push_back(ConstraintStr[i]);
 697       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 698       Record.clear();
 699       continue;
 700     }
 701     const Constant *C = cast<Constant>(V);
 702     unsigned Code = -1U;
 703     unsigned AbbrevToUse = 0;
 704     if (C->isNullValue()) {
 705       Code = bitc::CST_CODE_NULL;
 706     } else if (isa<UndefValue>(C)) {
 707       Code = bitc::CST_CODE_UNDEF;
 708     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 709       if (IV->getBitWidth() <= 64) {
 710         int64_t V = IV->getSExtValue();
 711         if (V >= 0)
 712           Record.push_back(V << 1);
 713         else
 714           Record.push_back((-V << 1) | 1);
 715         Code = bitc::CST_CODE_INTEGER;
 716         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 717       } else {                             // Wide integers, > 64 bits in size.
 718         // We have an arbitrary precision integer value to write whose
 719         // bit width is > 64. However, in canonical unsigned integer
 720         // format it is likely that the high bits are going to be zero.
 721         // So, we only write the number of active words.
 722         unsigned NWords = IV->getValue().getActiveWords();
 723         const uint64_t *RawWords = IV->getValue().getRawData();
 724         for (unsigned i = 0; i != NWords; ++i) {
 725           int64_t V = RawWords[i];
 726           if (V >= 0)
 727             Record.push_back(V << 1);
 728           else
 729             Record.push_back((-V << 1) | 1);
 730         }
 731         Code = bitc::CST_CODE_WIDE_INTEGER;
 732       }
 733     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 734       Code = bitc::CST_CODE_FLOAT;
 735       const Type *Ty = CFP->getType();
 736       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 737         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 738       } else if (Ty->isX86_FP80Ty()) {
 739         // api needed to prevent premature destruction
 740         // bits are not in the same order as a normal i80 APInt, compensate.
 741         APInt api = CFP->getValueAPF().bitcastToAPInt();
 742         const uint64_t *p = api.getRawData();
 743         Record.push_back((p[1] << 48) | (p[0] >> 16));
 744         Record.push_back(p[0] & 0xffffLL);
 745       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 746         APInt api = CFP->getValueAPF().bitcastToAPInt();
 747         const uint64_t *p = api.getRawData();
 748         Record.push_back(p[0]);
 749         Record.push_back(p[1]);
 750       } else {
 751         assert (0 && "Unknown FP type!");
 752       }
 753     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 754       const ConstantArray *CA = cast<ConstantArray>(C);
 755       // Emit constant strings specially.
 756       unsigned NumOps = CA->getNumOperands();
 757       // If this is a null-terminated string, use the denser CSTRING encoding.
 758       if (CA->getOperand(NumOps-1)->isNullValue()) {
 759         Code = bitc::CST_CODE_CSTRING;
 760         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 761       } else {
 762         Code = bitc::CST_CODE_STRING;
 763         AbbrevToUse = String8Abbrev;
 764       }
 765       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 766       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 767       for (unsigned i = 0; i != NumOps; ++i) {
 768         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 769         Record.push_back(V);
 770         isCStr7 &= (V & 128) == 0;
 771         if (isCStrChar6)
 772           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 773       }
 774
 775       if (isCStrChar6)
 776         AbbrevToUse = CString6Abbrev;
 777       else if (isCStr7)
 778         AbbrevToUse = CString7Abbrev;
 779     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 780                isa<ConstantVector>(V)) {
 781       Code = bitc::CST_CODE_AGGREGATE;
 782       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 783         Record.push_back(VE.getValueID(C->getOperand(i)));
 784       AbbrevToUse = AggregateAbbrev;
 785     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 786       switch (CE->getOpcode()) {
 787       default:
 788         if (Instruction::isCast(CE->getOpcode())) {
 789           Code = bitc::CST_CODE_CE_CAST;
 790           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 791           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 792           Record.push_back(VE.getValueID(C->getOperand(0)));
 793           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 794         } else {
 795           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 796           Code = bitc::CST_CODE_CE_BINOP;
 797           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 798           Record.push_back(VE.getValueID(C->getOperand(0)));
 799           Record.push_back(VE.getValueID(C->getOperand(1)));
 800           uint64_t Flags = GetOptimizationFlags(CE);
 801           if (Flags != 0)
 802             Record.push_back(Flags);
 803         }
 804         break;
 805       case Instruction::GetElementPtr:
 806         Code = bitc::CST_CODE_CE_GEP;
 807         if (cast<GEPOperator>(C)->isInBounds())
 808           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 809         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 810           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 811           Record.push_back(VE.getValueID(C->getOperand(i)));
 812         }
 813         break;
 814       case Instruction::Select:
 815         Code = bitc::CST_CODE_CE_SELECT;
 816         Record.push_back(VE.getValueID(C->getOperand(0)));
 817         Record.push_back(VE.getValueID(C->getOperand(1)));
 818         Record.push_back(VE.getValueID(C->getOperand(2)));
 819         break;
 820       case Instruction::ExtractElement:
 821         Code = bitc::CST_CODE_CE_EXTRACTELT;
 822         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 823         Record.push_back(VE.getValueID(C->getOperand(0)));
 824         Record.push_back(VE.getValueID(C->getOperand(1)));
 825         break;
 826       case Instruction::InsertElement:
 827         Code = bitc::CST_CODE_CE_INSERTELT;
 828         Record.push_back(VE.getValueID(C->getOperand(0)));
 829         Record.push_back(VE.getValueID(C->getOperand(1)));
 830         Record.push_back(VE.getValueID(C->getOperand(2)));
 831         break;
 832       case Instruction::ShuffleVector:
 833         // If the return type and argument types are the same, this is a
 834         // standard shufflevector instruction.  If the types are different,
 835         // then the shuffle is widening or truncating the input vectors, and
 836         // the argument type must also be encoded.
 837         if (C->getType() == C->getOperand(0)->getType()) {
 838           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 839         } else {
 840           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 841           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 842         }
 843         Record.push_back(VE.getValueID(C->getOperand(0)));
 844         Record.push_back(VE.getValueID(C->getOperand(1)));
 845         Record.push_back(VE.getValueID(C->getOperand(2)));
 846         break;
 847       case Instruction::ICmp:
 848       case Instruction::FCmp:
 849         Code = bitc::CST_CODE_CE_CMP;
 850         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 851         Record.push_back(VE.getValueID(C->getOperand(0)));
 852         Record.push_back(VE.getValueID(C->getOperand(1)));
 853         Record.push_back(CE->getPredicate());
 854         break;
 855       }
 856     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 857       assert(BA->getFunction() == BA->getBasicBlock()->getParent() &&
 858              "Malformed blockaddress");
 859       Code = bitc::CST_CODE_BLOCKADDRESS;
 860       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 861       Record.push_back(VE.getValueID(BA->getFunction()));
 862       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 863     } else {
 864       llvm_unreachable("Unknown constant!");
 865     }
 866     Stream.EmitRecord(Code, Record, AbbrevToUse);
 867     Record.clear();
 868   }
 869
 870   Stream.ExitBlock();
 871 }
 872
 873 static void WriteModuleConstants(const ValueEnumerator &VE,
 874                                  BitstreamWriter &Stream) {
 875   const ValueEnumerator::ValueList &Vals = VE.getValues();
 876
 877   // Find the first constant to emit, which is the first non-globalvalue value.
 878   // We know globalvalues have been emitted by WriteModuleInfo.
 879   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 880     if (!isa<GlobalValue>(Vals[i].first)) {
 881       WriteConstants(i, Vals.size(), VE, Stream, true);
 882       return;
 883     }
 884   }
 885 }
 886
 887 /// PushValueAndType - The file has to encode both the value and type id for
 888 /// many values, because we need to know what type to create for forward
 889 /// references.  However, most operands are not forward references, so this type
 890 /// field is not needed.
 891 ///
 892 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 893 /// instruction ID, then it is a forward reference, and it also includes the
 894 /// type ID.
 895 static bool PushValueAndType(const Value *V, unsigned InstID,
 896                              SmallVector<unsigned, 64> &Vals,
 897                              ValueEnumerator &VE) {
 898   unsigned ValID = VE.getValueID(V);
 899   Vals.push_back(ValID);
 900   if (ValID >= InstID) {
 901     Vals.push_back(VE.getTypeID(V->getType()));
 902     return true;
 903   }
 904   return false;
 905 }
 906
 907 /// WriteInstruction - Emit an instruction to the specified stream.
 908 static void WriteInstruction(const Instruction &I, unsigned InstID,
 909                              ValueEnumerator &VE, BitstreamWriter &Stream,
 910                              SmallVector<unsigned, 64> &Vals) {
 911   unsigned Code = 0;
 912   unsigned AbbrevToUse = 0;
 913   VE.setInstructionID(&I);
 914   switch (I.getOpcode()) {
 915   default:
 916     if (Instruction::isCast(I.getOpcode())) {
 917       Code = bitc::FUNC_CODE_INST_CAST;
 918       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 919         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 920       Vals.push_back(VE.getTypeID(I.getType()));
 921       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 922     } else {
 923       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 924       Code = bitc::FUNC_CODE_INST_BINOP;
 925       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 926         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 927       Vals.push_back(VE.getValueID(I.getOperand(1)));
 928       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 929       uint64_t Flags = GetOptimizationFlags(&I);
 930       if (Flags != 0) {
 931         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 932           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 933         Vals.push_back(Flags);
 934       }
 935     }
 936     break;
 937
 938   case Instruction::GetElementPtr:
 939     Code = bitc::FUNC_CODE_INST_GEP;
 940     if (cast<GEPOperator>(&I)->isInBounds())
 941       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 942     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 943       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 944     break;
 945   case Instruction::ExtractValue: {
 946     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 947     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 948     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 949     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 950       Vals.push_back(*i);
 951     break;
 952   }
 953   case Instruction::InsertValue: {
 954     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 955     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 956     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 957     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 958     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 959       Vals.push_back(*i);
 960     break;
 961   }
 962   case Instruction::Select:
 963     Code = bitc::FUNC_CODE_INST_VSELECT;
 964     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 965     Vals.push_back(VE.getValueID(I.getOperand(2)));
 966     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 967     break;
 968   case Instruction::ExtractElement:
 969     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 970     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 971     Vals.push_back(VE.getValueID(I.getOperand(1)));
 972     break;
 973   case Instruction::InsertElement:
 974     Code = bitc::FUNC_CODE_INST_INSERTELT;
 975     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 976     Vals.push_back(VE.getValueID(I.getOperand(1)));
 977     Vals.push_back(VE.getValueID(I.getOperand(2)));
 978     break;
 979   case Instruction::ShuffleVector:
 980     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 981     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 982     Vals.push_back(VE.getValueID(I.getOperand(1)));
 983     Vals.push_back(VE.getValueID(I.getOperand(2)));
 984     break;
 985   case Instruction::ICmp:
 986   case Instruction::FCmp:
 987     // compare returning Int1Ty or vector of Int1Ty
 988     Code = bitc::FUNC_CODE_INST_CMP2;
 989     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 990     Vals.push_back(VE.getValueID(I.getOperand(1)));
 991     Vals.push_back(cast<CmpInst>(I).getPredicate());
 992     break;
 993
 994   case Instruction::Ret:
 995     {
 996       Code = bitc::FUNC_CODE_INST_RET;
 997       unsigned NumOperands = I.getNumOperands();
 998       if (NumOperands == 0)
 999         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1000       else if (NumOperands == 1) {
1001         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1002           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1003       } else {
1004         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1005           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1006       }
1007     }
1008     break;
1009   case Instruction::Br:
1010     {
1011       Code = bitc::FUNC_CODE_INST_BR;
1012       BranchInst &II = cast<BranchInst>(I);
1013       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1014       if (II.isConditional()) {
1015         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1016         Vals.push_back(VE.getValueID(II.getCondition()));
1017       }
1018     }
1019     break;
1020   case Instruction::Switch:
1021     Code = bitc::FUNC_CODE_INST_SWITCH;
1022     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1023     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1024       Vals.push_back(VE.getValueID(I.getOperand(i)));
1025     break;
1026   case Instruction::IndirectBr:
1027     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1028     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1029     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1030       Vals.push_back(VE.getValueID(I.getOperand(i)));
1031     break;
1032
1033   case Instruction::Invoke: {
1034     const InvokeInst *II = cast<InvokeInst>(&I);
1035     const Value *Callee(II->getCalledValue());
1036     const PointerType *PTy = cast<PointerType>(Callee->getType());
1037     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1038     Code = bitc::FUNC_CODE_INST_INVOKE;
1039
1040     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1041     Vals.push_back(II->getCallingConv());
1042     Vals.push_back(VE.getValueID(II->getNormalDest()));
1043     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1044     PushValueAndType(Callee, InstID, Vals, VE);
1045
1046     // Emit value #'s for the fixed parameters.
1047     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1048       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
1049
1050     // Emit type/value pairs for varargs params.
1051     if (FTy->isVarArg()) {
1052       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
1053            i != e; ++i)
1054         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1055     }
1056     break;
1057   }
1058   case Instruction::Unwind:
1059     Code = bitc::FUNC_CODE_INST_UNWIND;
1060     break;
1061   case Instruction::Unreachable:
1062     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1063     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1064     break;
1065
1066   case Instruction::PHI:
1067     Code = bitc::FUNC_CODE_INST_PHI;
1068     Vals.push_back(VE.getTypeID(I.getType()));
1069     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1070       Vals.push_back(VE.getValueID(I.getOperand(i)));
1071     break;
1072
1073   case Instruction::Alloca:
1074     Code = bitc::FUNC_CODE_INST_ALLOCA;
1075     Vals.push_back(VE.getTypeID(I.getType()));
1076     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1077     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1078     break;
1079
1080   case Instruction::Load:
1081     Code = bitc::FUNC_CODE_INST_LOAD;
1082     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1083       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1084
1085     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1086     Vals.push_back(cast<LoadInst>(I).isVolatile());
1087     break;
1088   case Instruction::Store:
1089     Code = bitc::FUNC_CODE_INST_STORE2;
1090     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1091     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1092     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1093     Vals.push_back(cast<StoreInst>(I).isVolatile());
1094     break;
1095   case Instruction::Call: {
1096     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1097     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1098
1099     Code = bitc::FUNC_CODE_INST_CALL;
1100
1101     const CallInst *CI = cast<CallInst>(&I);
1102     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1103     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1104     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1105
1106     // Emit value #'s for the fixed parameters.
1107     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1108       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1109
1110     // Emit type/value pairs for varargs params.
1111     if (FTy->isVarArg()) {
1112       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1113       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1114            i != e; ++i)
1115         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1116     }
1117     break;
1118   }
1119   case Instruction::VAArg:
1120     Code = bitc::FUNC_CODE_INST_VAARG;
1121     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1122     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1123     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1124     break;
1125   }
1126
1127   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1128   Vals.clear();
1129 }
1130
1131 // Emit names for globals/functions etc.
1132 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1133                                   const ValueEnumerator &VE,
1134                                   BitstreamWriter &Stream) {
1135   if (VST.empty()) return;
1136   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1137
1138   // FIXME: Set up the abbrev, we know how many values there are!
1139   // FIXME: We know if the type names can use 7-bit ascii.
1140   SmallVector<unsigned, 64> NameVals;
1141
1142   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1143        SI != SE; ++SI) {
1144
1145     const ValueName &Name = *SI;
1146
1147     // Figure out the encoding to use for the name.
1148     bool is7Bit = true;
1149     bool isChar6 = true;
1150     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1151          C != E; ++C) {
1152       if (isChar6)
1153         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1154       if ((unsigned char)*C & 128) {
1155         is7Bit = false;
1156         break;  // don't bother scanning the rest.
1157       }
1158     }
1159
1160     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1161
1162     // VST_ENTRY:   [valueid, namechar x N]
1163     // VST_BBENTRY: [bbid, namechar x N]
1164     unsigned Code;
1165     if (isa<BasicBlock>(SI->getValue())) {
1166       Code = bitc::VST_CODE_BBENTRY;
1167       if (isChar6)
1168         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1169     } else {
1170       Code = bitc::VST_CODE_ENTRY;
1171       if (isChar6)
1172         AbbrevToUse = VST_ENTRY_6_ABBREV;
1173       else if (is7Bit)
1174         AbbrevToUse = VST_ENTRY_7_ABBREV;
1175     }
1176
1177     NameVals.push_back(VE.getValueID(SI->getValue()));
1178     for (const char *P = Name.getKeyData(),
1179          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1180       NameVals.push_back((unsigned char)*P);
1181
1182     // Emit the finished record.
1183     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1184     NameVals.clear();
1185   }
1186   Stream.ExitBlock();
1187 }
1188
1189 /// WriteFunction - Emit a function body to the module stream.
1190 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1191                           BitstreamWriter &Stream) {
1192   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1193   VE.incorporateFunction(F);
1194
1195   SmallVector<unsigned, 64> Vals;
1196
1197   // Emit the number of basic blocks, so the reader can create them ahead of
1198   // time.
1199   Vals.push_back(VE.getBasicBlocks().size());
1200   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1201   Vals.clear();
1202
1203   // If there are function-local constants, emit them now.
1204   unsigned CstStart, CstEnd;
1205   VE.getFunctionConstantRange(CstStart, CstEnd);
1206   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1207
1208   // Keep a running idea of what the instruction ID is.
1209   unsigned InstID = CstEnd;
1210
1211   // Finally, emit all the instructions, in order.
1212   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1213     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1214          I != E; ++I) {
1215       WriteInstruction(*I, InstID, VE, Stream, Vals);
1216       if (I->getType() != Type::getVoidTy(F.getContext()))
1217         ++InstID;
1218     }
1219
1220   // Emit names for all the instructions etc.
1221   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1222
1223   WriteMetadataAttachment(F, VE, Stream);
1224   VE.purgeFunction();
1225   Stream.ExitBlock();
1226 }
1227
1228 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1229 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1230                                  const ValueEnumerator &VE,
1231                                  BitstreamWriter &Stream) {
1232   if (TST.empty()) return;
1233
1234   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1235
1236   // 7-bit fixed width VST_CODE_ENTRY strings.
1237   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1238   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1239   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1240                             Log2_32_Ceil(VE.getTypes().size()+1)));
1241   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1243   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1244
1245   SmallVector<unsigned, 64> NameVals;
1246
1247   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1248        TI != TE; ++TI) {
1249     // TST_ENTRY: [typeid, namechar x N]
1250     NameVals.push_back(VE.getTypeID(TI->second));
1251
1252     const std::string &Str = TI->first;
1253     bool is7Bit = true;
1254     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1255       NameVals.push_back((unsigned char)Str[i]);
1256       if (Str[i] & 128)
1257         is7Bit = false;
1258     }
1259
1260     // Emit the finished record.
1261     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1262     NameVals.clear();
1263   }
1264
1265   Stream.ExitBlock();
1266 }
1267
1268 // Emit blockinfo, which defines the standard abbreviations etc.
1269 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1270   // We only want to emit block info records for blocks that have multiple
1271   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1272   // blocks can defined their abbrevs inline.
1273   Stream.EnterBlockInfoBlock(2);
1274
1275   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1276     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1281     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1282                                    Abbv) != VST_ENTRY_8_ABBREV)
1283       llvm_unreachable("Unexpected abbrev ordering!");
1284   }
1285
1286   { // 7-bit fixed width VST_ENTRY strings.
1287     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1288     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1292     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1293                                    Abbv) != VST_ENTRY_7_ABBREV)
1294       llvm_unreachable("Unexpected abbrev ordering!");
1295   }
1296   { // 6-bit char6 VST_ENTRY strings.
1297     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1298     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1302     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1303                                    Abbv) != VST_ENTRY_6_ABBREV)
1304       llvm_unreachable("Unexpected abbrev ordering!");
1305   }
1306   { // 6-bit char6 VST_BBENTRY strings.
1307     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1308     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1312     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1313                                    Abbv) != VST_BBENTRY_6_ABBREV)
1314       llvm_unreachable("Unexpected abbrev ordering!");
1315   }
1316
1317
1318
1319   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1320     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1321     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1323                               Log2_32_Ceil(VE.getTypes().size()+1)));
1324     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1325                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1326       llvm_unreachable("Unexpected abbrev ordering!");
1327   }
1328
1329   { // INTEGER abbrev for CONSTANTS_BLOCK.
1330     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1331     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1333     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1334                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1335       llvm_unreachable("Unexpected abbrev ordering!");
1336   }
1337
1338   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1339     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1340     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1341     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1343                               Log2_32_Ceil(VE.getTypes().size()+1)));
1344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1345
1346     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1347                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1348       llvm_unreachable("Unexpected abbrev ordering!");
1349   }
1350   { // NULL abbrev for CONSTANTS_BLOCK.
1351     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1352     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1353     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1354                                    Abbv) != CONSTANTS_NULL_Abbrev)
1355       llvm_unreachable("Unexpected abbrev ordering!");
1356   }
1357
1358   // FIXME: This should only use space for first class types!
1359
1360   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1361     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1362     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1366     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1367                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1368       llvm_unreachable("Unexpected abbrev ordering!");
1369   }
1370   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1371     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1372     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1376     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1377                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1378       llvm_unreachable("Unexpected abbrev ordering!");
1379   }
1380   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1381     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1382     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1387     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1388                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1389       llvm_unreachable("Unexpected abbrev ordering!");
1390   }
1391   { // INST_CAST abbrev for FUNCTION_BLOCK.
1392     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1393     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1396                               Log2_32_Ceil(VE.getTypes().size()+1)));
1397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1398     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1399                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1400       llvm_unreachable("Unexpected abbrev ordering!");
1401   }
1402
1403   { // INST_RET abbrev for FUNCTION_BLOCK.
1404     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1405     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1406     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1407                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1408       llvm_unreachable("Unexpected abbrev ordering!");
1409   }
1410   { // INST_RET abbrev for FUNCTION_BLOCK.
1411     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1412     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1414     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1415                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1416       llvm_unreachable("Unexpected abbrev ordering!");
1417   }
1418   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1419     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1420     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1421     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1422                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1423       llvm_unreachable("Unexpected abbrev ordering!");
1424   }
1425
1426   Stream.ExitBlock();
1427 }
1428
1429
1430 /// WriteModule - Emit the specified module to the bitstream.
1431 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1432   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1433
1434   // Emit the version number if it is non-zero.
1435   if (CurVersion) {
1436     SmallVector<unsigned, 1> Vals;
1437     Vals.push_back(CurVersion);
1438     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1439   }
1440
1441   // Analyze the module, enumerating globals, functions, etc.
1442   ValueEnumerator VE(M);
1443
1444   // Emit blockinfo, which defines the standard abbreviations etc.
1445   WriteBlockInfo(VE, Stream);
1446
1447   // Emit information about parameter attributes.
1448   WriteAttributeTable(VE, Stream);
1449
1450   // Emit information describing all of the types in the module.
1451   WriteTypeTable(VE, Stream);
1452
1453   // Emit top-level description of module, including target triple, inline asm,
1454   // descriptors for global variables, and function prototype info.
1455   WriteModuleInfo(M, VE, Stream);
1456
1457   // Emit constants.
1458   WriteModuleConstants(VE, Stream);
1459
1460   // Emit metadata.
1461   WriteModuleMetadata(VE, Stream);
1462
1463   // Emit function bodies.
1464   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1465     if (!I->isDeclaration())
1466       WriteFunction(*I, VE, Stream);
1467
1468   // Emit metadata.
1469   WriteModuleMetadataStore(M, VE, Stream);
1470
1471   // Emit the type symbol table information.
1472   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1473
1474   // Emit names for globals/functions etc.
1475   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1476
1477   Stream.ExitBlock();
1478 }
1479
1480 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1481 /// header and trailer to make it compatible with the system archiver.  To do
1482 /// this we emit the following header, and then emit a trailer that pads the
1483 /// file out to be a multiple of 16 bytes.
1484 ///
1485 /// struct bc_header {
1486 ///   uint32_t Magic;         // 0x0B17C0DE
1487 ///   uint32_t Version;       // Version, currently always 0.
1488 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1489 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1490 ///   uint32_t CPUType;       // CPU specifier.
1491 ///   ... potentially more later ...
1492 /// };
1493 enum {
1494   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1495   DarwinBCHeaderSize = 5*4
1496 };
1497
1498 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1499                                const std::string &TT) {
1500   unsigned CPUType = ~0U;
1501
1502   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1503   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1504   // specific constants here because they are implicitly part of the Darwin ABI.
1505   enum {
1506     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1507     DARWIN_CPU_TYPE_X86        = 7,
1508     DARWIN_CPU_TYPE_POWERPC    = 18
1509   };
1510
1511   if (TT.find("x86_64-") == 0)
1512     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1513   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1514            TT[4] == '-' && TT[1] - '3' < 6)
1515     CPUType = DARWIN_CPU_TYPE_X86;
1516   else if (TT.find("powerpc-") == 0)
1517     CPUType = DARWIN_CPU_TYPE_POWERPC;
1518   else if (TT.find("powerpc64-") == 0)
1519     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1520
1521   // Traditional Bitcode starts after header.
1522   unsigned BCOffset = DarwinBCHeaderSize;
1523
1524   Stream.Emit(0x0B17C0DE, 32);
1525   Stream.Emit(0         , 32);  // Version.
1526   Stream.Emit(BCOffset  , 32);
1527   Stream.Emit(0         , 32);  // Filled in later.
1528   Stream.Emit(CPUType   , 32);
1529 }
1530
1531 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1532 /// finalize the header.
1533 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1534   // Update the size field in the header.
1535   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1536
1537   // If the file is not a multiple of 16 bytes, insert dummy padding.
1538   while (BufferSize & 15) {
1539     Stream.Emit(0, 8);
1540     ++BufferSize;
1541   }
1542 }
1543
1544
1545 /// WriteBitcodeToFile - Write the specified module to the specified output
1546 /// stream.
1547 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1548   std::vector<unsigned char> Buffer;
1549   BitstreamWriter Stream(Buffer);
1550
1551   Buffer.reserve(256*1024);
1552
1553   WriteBitcodeToStream( M, Stream );
1554
1555   // If writing to stdout, set binary mode.
1556   if (&llvm::outs() == &Out)
1557     sys::Program::ChangeStdoutToBinary();
1558
1559   // Write the generated bitstream to "Out".
1560   Out.write((char*)&Buffer.front(), Buffer.size());
1561
1562   // Make sure it hits disk now.
1563   Out.flush();
1564 }
1565
1566 /// WriteBitcodeToStream - Write the specified module to the specified output
1567 /// stream.
1568 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1569   // If this is darwin, emit a file header and trailer if needed.
1570   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1571   if (isDarwin)
1572     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1573
1574   // Emit the file header.
1575   Stream.Emit((unsigned)'B', 8);
1576   Stream.Emit((unsigned)'C', 8);
1577   Stream.Emit(0x0, 4);
1578   Stream.Emit(0xC, 4);
1579   Stream.Emit(0xE, 4);
1580   Stream.Emit(0xD, 4);
1581
1582   // Emit the module.
1583   WriteModule(M, Stream);
1584
1585   if (isDarwin)
1586     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1587 }