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/Metadata.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/Operator.h"
  25 #include "llvm/TypeSymbolTable.h"
  26 #include "llvm/ValueSymbolTable.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/Streams.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->hasNoSignedOverflow())
 465       Flags |= 1 << bitc::OBO_NO_SIGNED_OVERFLOW;
 466     if (OBO->hasNoUnsignedOverflow())
 467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_OVERFLOW;
 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 /// WriteValues - Write Constants and Metadata.
 477 /// This function could use some refactoring help.
 478 static void WriteValues(unsigned FirstVal, unsigned LastVal,
 479                         const ValueEnumerator &VE,
 480                         BitstreamWriter &Stream, bool isGlobal) {
 481   if (FirstVal == LastVal) return;
 482
 483   // MODULE_BLOCK_ID is 0, which is not handled here. So it is OK to use
 484   // 0 as the initializer to indicate that block is not set.
 485   enum bitc::BlockIDs LastBlockID = bitc::MODULE_BLOCK_ID;
 486
 487   unsigned AggregateAbbrev = 0;
 488   unsigned String8Abbrev = 0;
 489   unsigned CString7Abbrev = 0;
 490   unsigned CString6Abbrev = 0;
 491   unsigned MDSAbbrev = 0;
 492
 493   SmallVector<uint64_t, 64> Record;
 494
 495   const ValueEnumerator::ValueList &Vals = VE.getValues();
 496   const Type *LastTy = 0;
 497   for (unsigned i = FirstVal; i != LastVal; ++i) {
 498     const Value *V = Vals[i].first;
 499     if (isa<MetadataBase>(V)) {
 500       if (LastBlockID != bitc::METADATA_BLOCK_ID) {
 501         // Exit privious block.
 502         if (LastBlockID != bitc::MODULE_BLOCK_ID)
 503           Stream.ExitBlock();
 504
 505         LastBlockID = bitc::METADATA_BLOCK_ID;
 506         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 507         // Abbrev for METADATA_STRING.
 508         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 509         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 510         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 511         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 512         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 513       }
 514     }
 515     if (const MDString *MDS = dyn_cast<MDString>(V)) {
 516       // Code: [strchar x N]
 517       const char *StrBegin = MDS->begin();
 518       for (unsigned i = 0, e = MDS->length(); i != e; ++i)
 519         Record.push_back(StrBegin[i]);
 520
 521       // Emit the finished record.
 522       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 523       Record.clear();
 524       continue;
 525     } else if (const MDNode *N = dyn_cast<MDNode>(V)) {
 526       for (unsigned i = 0, e = N->getNumElements(); i != e; ++i) {
 527         if (N->getElement(i)) {
 528           Record.push_back(VE.getTypeID(N->getElement(i)->getType()));
 529           Record.push_back(VE.getValueID(N->getElement(i)));
 530         } else {
 531           Record.push_back(VE.getTypeID(Type::VoidTy));
 532           Record.push_back(0);
 533         }
 534       }
 535       Stream.EmitRecord(bitc::METADATA_NODE, Record, 0);
 536       Record.clear();
 537       continue;
 538     } else if (const NamedMDNode *NMD = dyn_cast<NamedMDNode>(V)) {
 539       // Write name.
 540       std::string Str = NMD->getNameStr();
 541       const char *StrBegin = Str.c_str();
 542       for (unsigned i = 0, e = Str.length(); i != e; ++i)
 543         Record.push_back(StrBegin[i]);
 544       Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 545       Record.clear();
 546
 547       // Write named metadata elements.
 548       for (unsigned i = 0, e = NMD->getNumElements(); i != e; ++i) {
 549         if (NMD->getElement(i))
 550           Record.push_back(VE.getValueID(NMD->getElement(i)));
 551         else
 552           Record.push_back(0);
 553       }
 554       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 555       Record.clear();
 556       continue;
 557     }
 558
 559     // If we need to switch block, do so now.
 560     if (LastBlockID != bitc::CONSTANTS_BLOCK_ID) {
 561       // Exit privious block.
 562       if (LastBlockID != bitc::MODULE_BLOCK_ID)
 563         Stream.ExitBlock();
 564
 565       LastBlockID = bitc::CONSTANTS_BLOCK_ID;
 566       Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 567       // If this is a constant pool for the module, emit module-specific abbrevs.
 568       if (isGlobal) {
 569         // Abbrev for CST_CODE_AGGREGATE.
 570         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 571         Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 572         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 573         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 574         AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 575
 576         // Abbrev for CST_CODE_STRING.
 577         Abbv = new BitCodeAbbrev();
 578         Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 579         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 580         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 581         String8Abbrev = Stream.EmitAbbrev(Abbv);
 582
 583         // Abbrev for CST_CODE_CSTRING.
 584         Abbv = new BitCodeAbbrev();
 585         Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 586         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 587         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 588         CString7Abbrev = Stream.EmitAbbrev(Abbv);
 589
 590         // Abbrev for CST_CODE_CSTRING.
 591         Abbv = new BitCodeAbbrev();
 592         Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 593         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 594         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 595         CString6Abbrev = Stream.EmitAbbrev(Abbv);
 596       }
 597
 598     }
 599     // If we need to switch types, do so now.
 600     if (V->getType() != LastTy) {
 601       LastTy = V->getType();
 602       Record.push_back(VE.getTypeID(LastTy));
 603       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 604                         CONSTANTS_SETTYPE_ABBREV);
 605       Record.clear();
 606     }
 607
 608     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 609       Record.push_back(unsigned(IA->hasSideEffects()));
 610
 611       // Add the asm string.
 612       const std::string &AsmStr = IA->getAsmString();
 613       Record.push_back(AsmStr.size());
 614       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 615         Record.push_back(AsmStr[i]);
 616
 617       // Add the constraint string.
 618       const std::string &ConstraintStr = IA->getConstraintString();
 619       Record.push_back(ConstraintStr.size());
 620       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 621         Record.push_back(ConstraintStr[i]);
 622       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 623       Record.clear();
 624       continue;
 625     }
 626     const Constant *C = cast<Constant>(V);
 627     unsigned Code = -1U;
 628     unsigned AbbrevToUse = 0;
 629     if (C->isNullValue()) {
 630       Code = bitc::CST_CODE_NULL;
 631     } else if (isa<UndefValue>(C)) {
 632       Code = bitc::CST_CODE_UNDEF;
 633     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 634       if (IV->getBitWidth() <= 64) {
 635         int64_t V = IV->getSExtValue();
 636         if (V >= 0)
 637           Record.push_back(V << 1);
 638         else
 639           Record.push_back((-V << 1) | 1);
 640         Code = bitc::CST_CODE_INTEGER;
 641         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 642       } else {                             // Wide integers, > 64 bits in size.
 643         // We have an arbitrary precision integer value to write whose
 644         // bit width is > 64. However, in canonical unsigned integer
 645         // format it is likely that the high bits are going to be zero.
 646         // So, we only write the number of active words.
 647         unsigned NWords = IV->getValue().getActiveWords();
 648         const uint64_t *RawWords = IV->getValue().getRawData();
 649         for (unsigned i = 0; i != NWords; ++i) {
 650           int64_t V = RawWords[i];
 651           if (V >= 0)
 652             Record.push_back(V << 1);
 653           else
 654             Record.push_back((-V << 1) | 1);
 655         }
 656         Code = bitc::CST_CODE_WIDE_INTEGER;
 657       }
 658     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 659       Code = bitc::CST_CODE_FLOAT;
 660       const Type *Ty = CFP->getType();
 661       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 662         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 663       } else if (Ty == Type::X86_FP80Ty) {
 664         // api needed to prevent premature destruction
 665         // bits are not in the same order as a normal i80 APInt, compensate.
 666         APInt api = CFP->getValueAPF().bitcastToAPInt();
 667         const uint64_t *p = api.getRawData();
 668         Record.push_back((p[1] << 48) | (p[0] >> 16));
 669         Record.push_back(p[0] & 0xffffLL);
 670       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 671         APInt api = CFP->getValueAPF().bitcastToAPInt();
 672         const uint64_t *p = api.getRawData();
 673         Record.push_back(p[0]);
 674         Record.push_back(p[1]);
 675       } else {
 676         assert (0 && "Unknown FP type!");
 677       }
 678     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 679       // Emit constant strings specially.
 680       unsigned NumOps = C->getNumOperands();
 681       // If this is a null-terminated string, use the denser CSTRING encoding.
 682       if (C->getOperand(NumOps-1)->isNullValue()) {
 683         Code = bitc::CST_CODE_CSTRING;
 684         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 685       } else {
 686         Code = bitc::CST_CODE_STRING;
 687         AbbrevToUse = String8Abbrev;
 688       }
 689       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 690       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 691       for (unsigned i = 0; i != NumOps; ++i) {
 692         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 693         Record.push_back(V);
 694         isCStr7 &= (V & 128) == 0;
 695         if (isCStrChar6)
 696           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 697       }
 698
 699       if (isCStrChar6)
 700         AbbrevToUse = CString6Abbrev;
 701       else if (isCStr7)
 702         AbbrevToUse = CString7Abbrev;
 703     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 704                isa<ConstantVector>(V)) {
 705       Code = bitc::CST_CODE_AGGREGATE;
 706       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 707         Record.push_back(VE.getValueID(C->getOperand(i)));
 708       AbbrevToUse = AggregateAbbrev;
 709     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 710       switch (CE->getOpcode()) {
 711       default:
 712         if (Instruction::isCast(CE->getOpcode())) {
 713           Code = bitc::CST_CODE_CE_CAST;
 714           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 715           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 716           Record.push_back(VE.getValueID(C->getOperand(0)));
 717           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 718         } else {
 719           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 720           Code = bitc::CST_CODE_CE_BINOP;
 721           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 722           Record.push_back(VE.getValueID(C->getOperand(0)));
 723           Record.push_back(VE.getValueID(C->getOperand(1)));
 724           uint64_t Flags = GetOptimizationFlags(CE);
 725           if (Flags != 0)
 726             Record.push_back(Flags);
 727         }
 728         break;
 729       case Instruction::GetElementPtr:
 730         Code = bitc::CST_CODE_CE_GEP;
 731         if (cast<GEPOperator>(C)->isInBounds())
 732           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 733         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 734           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 735           Record.push_back(VE.getValueID(C->getOperand(i)));
 736         }
 737         break;
 738       case Instruction::Select:
 739         Code = bitc::CST_CODE_CE_SELECT;
 740         Record.push_back(VE.getValueID(C->getOperand(0)));
 741         Record.push_back(VE.getValueID(C->getOperand(1)));
 742         Record.push_back(VE.getValueID(C->getOperand(2)));
 743         break;
 744       case Instruction::ExtractElement:
 745         Code = bitc::CST_CODE_CE_EXTRACTELT;
 746         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 747         Record.push_back(VE.getValueID(C->getOperand(0)));
 748         Record.push_back(VE.getValueID(C->getOperand(1)));
 749         break;
 750       case Instruction::InsertElement:
 751         Code = bitc::CST_CODE_CE_INSERTELT;
 752         Record.push_back(VE.getValueID(C->getOperand(0)));
 753         Record.push_back(VE.getValueID(C->getOperand(1)));
 754         Record.push_back(VE.getValueID(C->getOperand(2)));
 755         break;
 756       case Instruction::ShuffleVector:
 757         // If the return type and argument types are the same, this is a
 758         // standard shufflevector instruction.  If the types are different,
 759         // then the shuffle is widening or truncating the input vectors, and
 760         // the argument type must also be encoded.
 761         if (C->getType() == C->getOperand(0)->getType()) {
 762           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 763         } else {
 764           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 765           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 766         }
 767         Record.push_back(VE.getValueID(C->getOperand(0)));
 768         Record.push_back(VE.getValueID(C->getOperand(1)));
 769         Record.push_back(VE.getValueID(C->getOperand(2)));
 770         break;
 771       case Instruction::ICmp:
 772       case Instruction::FCmp:
 773         Code = bitc::CST_CODE_CE_CMP;
 774         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 775         Record.push_back(VE.getValueID(C->getOperand(0)));
 776         Record.push_back(VE.getValueID(C->getOperand(1)));
 777         Record.push_back(CE->getPredicate());
 778         break;
 779       }
 780     } else {
 781       llvm_unreachable("Unknown constant!");
 782     }
 783     Stream.EmitRecord(Code, Record, AbbrevToUse);
 784     Record.clear();
 785   }
 786
 787   Stream.ExitBlock();
 788 }
 789
 790 static void WriteModuleConstants(const ValueEnumerator &VE,
 791                                  BitstreamWriter &Stream) {
 792   const ValueEnumerator::ValueList &Vals = VE.getValues();
 793
 794   // Find the first constant to emit, which is the first non-globalvalue value.
 795   // We know globalvalues have been emitted by WriteModuleInfo.
 796   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 797     if (!isa<GlobalValue>(Vals[i].first)) {
 798       WriteValues(i, Vals.size(), VE, Stream, true);
 799       return;
 800     }
 801   }
 802 }
 803
 804 /// PushValueAndType - The file has to encode both the value and type id for
 805 /// many values, because we need to know what type to create for forward
 806 /// references.  However, most operands are not forward references, so this type
 807 /// field is not needed.
 808 ///
 809 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 810 /// instruction ID, then it is a forward reference, and it also includes the
 811 /// type ID.
 812 static bool PushValueAndType(const Value *V, unsigned InstID,
 813                              SmallVector<unsigned, 64> &Vals,
 814                              ValueEnumerator &VE) {
 815   unsigned ValID = VE.getValueID(V);
 816   Vals.push_back(ValID);
 817   if (ValID >= InstID) {
 818     Vals.push_back(VE.getTypeID(V->getType()));
 819     return true;
 820   }
 821   return false;
 822 }
 823
 824 /// WriteInstruction - Emit an instruction to the specified stream.
 825 static void WriteInstruction(const Instruction &I, unsigned InstID,
 826                              ValueEnumerator &VE, BitstreamWriter &Stream,
 827                              SmallVector<unsigned, 64> &Vals) {
 828   unsigned Code = 0;
 829   unsigned AbbrevToUse = 0;
 830   switch (I.getOpcode()) {
 831   default:
 832     if (Instruction::isCast(I.getOpcode())) {
 833       Code = bitc::FUNC_CODE_INST_CAST;
 834       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 835         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 836       Vals.push_back(VE.getTypeID(I.getType()));
 837       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 838     } else {
 839       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 840       Code = bitc::FUNC_CODE_INST_BINOP;
 841       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 842         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 843       Vals.push_back(VE.getValueID(I.getOperand(1)));
 844       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 845       uint64_t Flags = GetOptimizationFlags(&I);
 846       if (Flags != 0) {
 847         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
 848           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
 849         Vals.push_back(Flags);
 850       }
 851     }
 852     break;
 853
 854   case Instruction::GetElementPtr:
 855     Code = bitc::FUNC_CODE_INST_GEP;
 856     if (cast<GEPOperator>(&I)->isInBounds())
 857       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
 858     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 859       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 860     break;
 861   case Instruction::ExtractValue: {
 862     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 863     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 864     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 865     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 866       Vals.push_back(*i);
 867     break;
 868   }
 869   case Instruction::InsertValue: {
 870     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 871     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 872     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 873     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 874     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 875       Vals.push_back(*i);
 876     break;
 877   }
 878   case Instruction::Select:
 879     Code = bitc::FUNC_CODE_INST_VSELECT;
 880     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 881     Vals.push_back(VE.getValueID(I.getOperand(2)));
 882     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 883     break;
 884   case Instruction::ExtractElement:
 885     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 886     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 887     Vals.push_back(VE.getValueID(I.getOperand(1)));
 888     break;
 889   case Instruction::InsertElement:
 890     Code = bitc::FUNC_CODE_INST_INSERTELT;
 891     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 892     Vals.push_back(VE.getValueID(I.getOperand(1)));
 893     Vals.push_back(VE.getValueID(I.getOperand(2)));
 894     break;
 895   case Instruction::ShuffleVector:
 896     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 897     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 898     Vals.push_back(VE.getValueID(I.getOperand(1)));
 899     Vals.push_back(VE.getValueID(I.getOperand(2)));
 900     break;
 901   case Instruction::ICmp:
 902   case Instruction::FCmp:
 903     // compare returning Int1Ty or vector of Int1Ty
 904     Code = bitc::FUNC_CODE_INST_CMP2;
 905     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 906     Vals.push_back(VE.getValueID(I.getOperand(1)));
 907     Vals.push_back(cast<CmpInst>(I).getPredicate());
 908     break;
 909
 910   case Instruction::Ret:
 911     {
 912       Code = bitc::FUNC_CODE_INST_RET;
 913       unsigned NumOperands = I.getNumOperands();
 914       if (NumOperands == 0)
 915         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 916       else if (NumOperands == 1) {
 917         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 918           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 919       } else {
 920         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 921           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 922       }
 923     }
 924     break;
 925   case Instruction::Br:
 926     {
 927       Code = bitc::FUNC_CODE_INST_BR;
 928       BranchInst &II(cast<BranchInst>(I));
 929       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
 930       if (II.isConditional()) {
 931         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
 932         Vals.push_back(VE.getValueID(II.getCondition()));
 933       }
 934     }
 935     break;
 936   case Instruction::Switch:
 937     Code = bitc::FUNC_CODE_INST_SWITCH;
 938     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 939     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 940       Vals.push_back(VE.getValueID(I.getOperand(i)));
 941     break;
 942   case Instruction::Invoke: {
 943     const InvokeInst *II = cast<InvokeInst>(&I);
 944     const Value *Callee(II->getCalledValue());
 945     const PointerType *PTy = cast<PointerType>(Callee->getType());
 946     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 947     Code = bitc::FUNC_CODE_INST_INVOKE;
 948
 949     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 950     Vals.push_back(II->getCallingConv());
 951     Vals.push_back(VE.getValueID(II->getNormalDest()));
 952     Vals.push_back(VE.getValueID(II->getUnwindDest()));
 953     PushValueAndType(Callee, InstID, Vals, VE);
 954
 955     // Emit value #'s for the fixed parameters.
 956     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 957       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 958
 959     // Emit type/value pairs for varargs params.
 960     if (FTy->isVarArg()) {
 961       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 962            i != e; ++i)
 963         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 964     }
 965     break;
 966   }
 967   case Instruction::Unwind:
 968     Code = bitc::FUNC_CODE_INST_UNWIND;
 969     break;
 970   case Instruction::Unreachable:
 971     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 972     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 973     break;
 974
 975   case Instruction::PHI:
 976     Code = bitc::FUNC_CODE_INST_PHI;
 977     Vals.push_back(VE.getTypeID(I.getType()));
 978     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 979       Vals.push_back(VE.getValueID(I.getOperand(i)));
 980     break;
 981
 982   case Instruction::Malloc:
 983     Code = bitc::FUNC_CODE_INST_MALLOC;
 984     Vals.push_back(VE.getTypeID(I.getType()));
 985     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 986     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 987     break;
 988
 989   case Instruction::Free:
 990     Code = bitc::FUNC_CODE_INST_FREE;
 991     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 992     break;
 993
 994   case Instruction::Alloca:
 995     Code = bitc::FUNC_CODE_INST_ALLOCA;
 996     Vals.push_back(VE.getTypeID(I.getType()));
 997     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 998     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 999     break;
1000
1001   case Instruction::Load:
1002     Code = bitc::FUNC_CODE_INST_LOAD;
1003     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1004       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1005
1006     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1007     Vals.push_back(cast<LoadInst>(I).isVolatile());
1008     break;
1009   case Instruction::Store:
1010     Code = bitc::FUNC_CODE_INST_STORE2;
1011     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1012     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1013     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1014     Vals.push_back(cast<StoreInst>(I).isVolatile());
1015     break;
1016   case Instruction::Call: {
1017     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
1018     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1019
1020     Code = bitc::FUNC_CODE_INST_CALL;
1021
1022     const CallInst *CI = cast<CallInst>(&I);
1023     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
1024     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
1025     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
1026
1027     // Emit value #'s for the fixed parameters.
1028     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1029       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
1030
1031     // Emit type/value pairs for varargs params.
1032     if (FTy->isVarArg()) {
1033       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
1034       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
1035            i != e; ++i)
1036         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
1037     }
1038     break;
1039   }
1040   case Instruction::VAArg:
1041     Code = bitc::FUNC_CODE_INST_VAARG;
1042     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1043     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1044     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1045     break;
1046   }
1047
1048   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1049   Vals.clear();
1050 }
1051
1052 // Emit names for globals/functions etc.
1053 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1054                                   const ValueEnumerator &VE,
1055                                   BitstreamWriter &Stream) {
1056   if (VST.empty()) return;
1057   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1058
1059   // FIXME: Set up the abbrev, we know how many values there are!
1060   // FIXME: We know if the type names can use 7-bit ascii.
1061   SmallVector<unsigned, 64> NameVals;
1062
1063   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1064        SI != SE; ++SI) {
1065
1066     const ValueName &Name = *SI;
1067
1068     // Figure out the encoding to use for the name.
1069     bool is7Bit = true;
1070     bool isChar6 = true;
1071     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1072          C != E; ++C) {
1073       if (isChar6)
1074         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1075       if ((unsigned char)*C & 128) {
1076         is7Bit = false;
1077         break;  // don't bother scanning the rest.
1078       }
1079     }
1080
1081     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1082
1083     // VST_ENTRY:   [valueid, namechar x N]
1084     // VST_BBENTRY: [bbid, namechar x N]
1085     unsigned Code;
1086     if (isa<BasicBlock>(*SI->getValue())) {
1087       Code = bitc::VST_CODE_BBENTRY;
1088       if (isChar6)
1089         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1090     } else {
1091       Code = bitc::VST_CODE_ENTRY;
1092       if (isChar6)
1093         AbbrevToUse = VST_ENTRY_6_ABBREV;
1094       else if (is7Bit)
1095         AbbrevToUse = VST_ENTRY_7_ABBREV;
1096     }
1097
1098     NameVals.push_back(VE.getValueID(SI->getValue()));
1099     for (const char *P = Name.getKeyData(),
1100          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1101       NameVals.push_back((unsigned char)*P);
1102
1103     // Emit the finished record.
1104     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1105     NameVals.clear();
1106   }
1107   Stream.ExitBlock();
1108 }
1109
1110 /// WriteFunction - Emit a function body to the module stream.
1111 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1112                           BitstreamWriter &Stream) {
1113   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1114   VE.incorporateFunction(F);
1115
1116   SmallVector<unsigned, 64> Vals;
1117
1118   // Emit the number of basic blocks, so the reader can create them ahead of
1119   // time.
1120   Vals.push_back(VE.getBasicBlocks().size());
1121   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1122   Vals.clear();
1123
1124   // If there are function-local constants, emit them now.
1125   unsigned CstStart, CstEnd;
1126   VE.getFunctionConstantRange(CstStart, CstEnd);
1127   WriteValues(CstStart, CstEnd, VE, Stream, false);
1128
1129   // Keep a running idea of what the instruction ID is.
1130   unsigned InstID = CstEnd;
1131
1132   // Finally, emit all the instructions, in order.
1133   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1134     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1135          I != E; ++I) {
1136       WriteInstruction(*I, InstID, VE, Stream, Vals);
1137       if (I->getType() != Type::VoidTy)
1138         ++InstID;
1139     }
1140
1141   // Emit names for all the instructions etc.
1142   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1143
1144   VE.purgeFunction();
1145   Stream.ExitBlock();
1146 }
1147
1148 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1149 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1150                                  const ValueEnumerator &VE,
1151                                  BitstreamWriter &Stream) {
1152   if (TST.empty()) return;
1153
1154   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1155
1156   // 7-bit fixed width VST_CODE_ENTRY strings.
1157   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1158   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1160                             Log2_32_Ceil(VE.getTypes().size()+1)));
1161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1163   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1164
1165   SmallVector<unsigned, 64> NameVals;
1166
1167   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1168        TI != TE; ++TI) {
1169     // TST_ENTRY: [typeid, namechar x N]
1170     NameVals.push_back(VE.getTypeID(TI->second));
1171
1172     const std::string &Str = TI->first;
1173     bool is7Bit = true;
1174     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1175       NameVals.push_back((unsigned char)Str[i]);
1176       if (Str[i] & 128)
1177         is7Bit = false;
1178     }
1179
1180     // Emit the finished record.
1181     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1182     NameVals.clear();
1183   }
1184
1185   Stream.ExitBlock();
1186 }
1187
1188 // Emit blockinfo, which defines the standard abbreviations etc.
1189 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1190   // We only want to emit block info records for blocks that have multiple
1191   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1192   // blocks can defined their abbrevs inline.
1193   Stream.EnterBlockInfoBlock(2);
1194
1195   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1196     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1201     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1202                                    Abbv) != VST_ENTRY_8_ABBREV)
1203       llvm_unreachable("Unexpected abbrev ordering!");
1204   }
1205
1206   { // 7-bit fixed width VST_ENTRY strings.
1207     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1208     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1212     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1213                                    Abbv) != VST_ENTRY_7_ABBREV)
1214       llvm_unreachable("Unexpected abbrev ordering!");
1215   }
1216   { // 6-bit char6 VST_ENTRY strings.
1217     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1218     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1219     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1222     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1223                                    Abbv) != VST_ENTRY_6_ABBREV)
1224       llvm_unreachable("Unexpected abbrev ordering!");
1225   }
1226   { // 6-bit char6 VST_BBENTRY strings.
1227     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1228     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1229     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1230     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1231     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1232     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1233                                    Abbv) != VST_BBENTRY_6_ABBREV)
1234       llvm_unreachable("Unexpected abbrev ordering!");
1235   }
1236
1237
1238
1239   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1240     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1241     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1243                               Log2_32_Ceil(VE.getTypes().size()+1)));
1244     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1245                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1246       llvm_unreachable("Unexpected abbrev ordering!");
1247   }
1248
1249   { // INTEGER abbrev for CONSTANTS_BLOCK.
1250     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1251     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1253     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1254                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1255       llvm_unreachable("Unexpected abbrev ordering!");
1256   }
1257
1258   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1259     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1260     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1262     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1263                               Log2_32_Ceil(VE.getTypes().size()+1)));
1264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1265
1266     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1267                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1268       llvm_unreachable("Unexpected abbrev ordering!");
1269   }
1270   { // NULL abbrev for CONSTANTS_BLOCK.
1271     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1272     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1273     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1274                                    Abbv) != CONSTANTS_NULL_Abbrev)
1275       llvm_unreachable("Unexpected abbrev ordering!");
1276   }
1277
1278   // FIXME: This should only use space for first class types!
1279
1280   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1281     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1282     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1286     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1287                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1288       llvm_unreachable("Unexpected abbrev ordering!");
1289   }
1290   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1291     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1292     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1296     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1297                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1298       llvm_unreachable("Unexpected abbrev ordering!");
1299   }
1300   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1301     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1302     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1307     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1308                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1309       llvm_unreachable("Unexpected abbrev ordering!");
1310   }
1311   { // INST_CAST abbrev for FUNCTION_BLOCK.
1312     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1313     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1314     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1316                               Log2_32_Ceil(VE.getTypes().size()+1)));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1318     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1319                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1320       llvm_unreachable("Unexpected abbrev ordering!");
1321   }
1322
1323   { // INST_RET abbrev for FUNCTION_BLOCK.
1324     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1325     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1326     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1327                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1328       llvm_unreachable("Unexpected abbrev ordering!");
1329   }
1330   { // INST_RET abbrev for FUNCTION_BLOCK.
1331     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1332     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1334     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1335                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1336       llvm_unreachable("Unexpected abbrev ordering!");
1337   }
1338   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1339     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1340     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1341     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1342                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1343       llvm_unreachable("Unexpected abbrev ordering!");
1344   }
1345
1346   Stream.ExitBlock();
1347 }
1348
1349
1350 /// WriteModule - Emit the specified module to the bitstream.
1351 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1352   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1353
1354   // Emit the version number if it is non-zero.
1355   if (CurVersion) {
1356     SmallVector<unsigned, 1> Vals;
1357     Vals.push_back(CurVersion);
1358     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1359   }
1360
1361   // Analyze the module, enumerating globals, functions, etc.
1362   ValueEnumerator VE(M);
1363
1364   // Emit blockinfo, which defines the standard abbreviations etc.
1365   WriteBlockInfo(VE, Stream);
1366
1367   // Emit information about parameter attributes.
1368   WriteAttributeTable(VE, Stream);
1369
1370   // Emit information describing all of the types in the module.
1371   WriteTypeTable(VE, Stream);
1372
1373   // Emit top-level description of module, including target triple, inline asm,
1374   // descriptors for global variables, and function prototype info.
1375   WriteModuleInfo(M, VE, Stream);
1376
1377   // Emit constants.
1378   WriteModuleConstants(VE, Stream);
1379
1380   // Emit function bodies.
1381   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1382     if (!I->isDeclaration())
1383       WriteFunction(*I, VE, Stream);
1384
1385   // Emit the type symbol table information.
1386   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1387
1388   // Emit names for globals/functions etc.
1389   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1390
1391   Stream.ExitBlock();
1392 }
1393
1394 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1395 /// header and trailer to make it compatible with the system archiver.  To do
1396 /// this we emit the following header, and then emit a trailer that pads the
1397 /// file out to be a multiple of 16 bytes.
1398 ///
1399 /// struct bc_header {
1400 ///   uint32_t Magic;         // 0x0B17C0DE
1401 ///   uint32_t Version;       // Version, currently always 0.
1402 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1403 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1404 ///   uint32_t CPUType;       // CPU specifier.
1405 ///   ... potentially more later ...
1406 /// };
1407 enum {
1408   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1409   DarwinBCHeaderSize = 5*4
1410 };
1411
1412 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1413                                const std::string &TT) {
1414   unsigned CPUType = ~0U;
1415
1416   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1417   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1418   // specific constants here because they are implicitly part of the Darwin ABI.
1419   enum {
1420     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1421     DARWIN_CPU_TYPE_X86        = 7,
1422     DARWIN_CPU_TYPE_POWERPC    = 18
1423   };
1424
1425   if (TT.find("x86_64-") == 0)
1426     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1427   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1428            TT[4] == '-' && TT[1] - '3' < 6)
1429     CPUType = DARWIN_CPU_TYPE_X86;
1430   else if (TT.find("powerpc-") == 0)
1431     CPUType = DARWIN_CPU_TYPE_POWERPC;
1432   else if (TT.find("powerpc64-") == 0)
1433     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1434
1435   // Traditional Bitcode starts after header.
1436   unsigned BCOffset = DarwinBCHeaderSize;
1437
1438   Stream.Emit(0x0B17C0DE, 32);
1439   Stream.Emit(0         , 32);  // Version.
1440   Stream.Emit(BCOffset  , 32);
1441   Stream.Emit(0         , 32);  // Filled in later.
1442   Stream.Emit(CPUType   , 32);
1443 }
1444
1445 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1446 /// finalize the header.
1447 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1448   // Update the size field in the header.
1449   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1450
1451   // If the file is not a multiple of 16 bytes, insert dummy padding.
1452   while (BufferSize & 15) {
1453     Stream.Emit(0, 8);
1454     ++BufferSize;
1455   }
1456 }
1457
1458
1459 /// WriteBitcodeToFile - Write the specified module to the specified output
1460 /// stream.
1461 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1462   raw_os_ostream RawOut(Out);
1463   // If writing to stdout, set binary mode.
1464   if (llvm::cout == Out)
1465     sys::Program::ChangeStdoutToBinary();
1466   WriteBitcodeToFile(M, RawOut);
1467 }
1468
1469 /// WriteBitcodeToFile - Write the specified module to the specified output
1470 /// stream.
1471 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1472   std::vector<unsigned char> Buffer;
1473   BitstreamWriter Stream(Buffer);
1474
1475   Buffer.reserve(256*1024);
1476
1477   WriteBitcodeToStream( M, Stream );
1478
1479   // If writing to stdout, set binary mode.
1480   if (&llvm::outs() == &Out)
1481     sys::Program::ChangeStdoutToBinary();
1482
1483   // Write the generated bitstream to "Out".
1484   Out.write((char*)&Buffer.front(), Buffer.size());
1485
1486   // Make sure it hits disk now.
1487   Out.flush();
1488 }
1489
1490 /// WriteBitcodeToStream - Write the specified module to the specified output
1491 /// stream.
1492 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1493   // If this is darwin, emit a file header and trailer if needed.
1494   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1495   if (isDarwin)
1496     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1497
1498   // Emit the file header.
1499   Stream.Emit((unsigned)'B', 8);
1500   Stream.Emit((unsigned)'C', 8);
1501   Stream.Emit(0x0, 4);
1502   Stream.Emit(0xC, 4);
1503   Stream.Emit(0xE, 4);
1504   Stream.Emit(0xD, 4);
1505
1506   // Emit the module.
1507   WriteModule(M, Stream);
1508
1509   if (isDarwin)
1510     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1511 }