lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Operator.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/ADT/Triple.h"
  26 #include "llvm/Support/ErrorHandling.h"
  27 #include "llvm/Support/MathExtras.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include "llvm/Support/Program.h"
  30 #include <cctype>
  31 #include <map>
  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 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 105   switch (Ordering) {
 106   default: llvm_unreachable("Unknown atomic ordering");
 107   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 108   case Unordered: return bitc::ORDERING_UNORDERED;
 109   case Monotonic: return bitc::ORDERING_MONOTONIC;
 110   case Acquire: return bitc::ORDERING_ACQUIRE;
 111   case Release: return bitc::ORDERING_RELEASE;
 112   case AcquireRelease: return bitc::ORDERING_ACQREL;
 113   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 114   }
 115 }
 116
 117 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 118   switch (SynchScope) {
 119   default: llvm_unreachable("Unknown synchronization scope");
 120   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 121   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 122   }
 123 }
 124
 125 static void WriteStringRecord(unsigned Code, StringRef Str,
 126                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 127   SmallVector<unsigned, 64> Vals;
 128
 129   // Code: [strchar x N]
 130   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 131     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 132       AbbrevToUse = 0;
 133     Vals.push_back(Str[i]);
 134   }
 135
 136   // Emit the finished record.
 137   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 138 }
 139
 140 // Emit information about parameter attributes.
 141 static void WriteAttributeTable(const ValueEnumerator &VE,
 142                                 BitstreamWriter &Stream) {
 143   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 144   if (Attrs.empty()) return;
 145
 146   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 147
 148   SmallVector<uint64_t, 64> Record;
 149   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 150     const AttrListPtr &A = Attrs[i];
 151     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 152       const AttributeWithIndex &PAWI = A.getSlot(i);
 153       Record.push_back(PAWI.Index);
 154
 155       // FIXME: remove in LLVM 3.0
 156       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 157       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 158       // 11 bits.
 159       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 160       if (PAWI.Attrs & Attribute::Alignment)
 161         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 162       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 163
 164       Record.push_back(FauxAttr);
 165     }
 166
 167     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 168     Record.clear();
 169   }
 170
 171   Stream.ExitBlock();
 172 }
 173
 174 /// WriteTypeTable - Write out the type table for a module.
 175 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 176   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 177
 178   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 179   SmallVector<uint64_t, 64> TypeVals;
 180
 181   // Abbrev for TYPE_CODE_POINTER.
 182   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 183   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 185                             Log2_32_Ceil(VE.getTypes().size()+1)));
 186   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 187   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 188
 189   // Abbrev for TYPE_CODE_FUNCTION.
 190   Abbv = new BitCodeAbbrev();
 191   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 193   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 196                             Log2_32_Ceil(VE.getTypes().size()+1)));
 197   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 198
 199   // Abbrev for TYPE_CODE_STRUCT_ANON.
 200   Abbv = new BitCodeAbbrev();
 201   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 205                             Log2_32_Ceil(VE.getTypes().size()+1)));
 206   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 207
 208   // Abbrev for TYPE_CODE_STRUCT_NAME.
 209   Abbv = new BitCodeAbbrev();
 210   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 211   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 213   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 214
 215   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 216   Abbv = new BitCodeAbbrev();
 217   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 219   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 221                             Log2_32_Ceil(VE.getTypes().size()+1)));
 222   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 223
 224
 225   // Abbrev for TYPE_CODE_ARRAY.
 226   Abbv = new BitCodeAbbrev();
 227   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 230                             Log2_32_Ceil(VE.getTypes().size()+1)));
 231   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 232
 233   // Emit an entry count so the reader can reserve space.
 234   TypeVals.push_back(TypeList.size());
 235   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 236   TypeVals.clear();
 237
 238   // Loop over all of the types, emitting each in turn.
 239   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 240     Type *T = TypeList[i];
 241     int AbbrevToUse = 0;
 242     unsigned Code = 0;
 243
 244     switch (T->getTypeID()) {
 245     default: llvm_unreachable("Unknown type!");
 246     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
 247     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
 248     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
 249     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
 250     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128; break;
 251     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 252     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;  break;
 253     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA; break;
 254     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX; break;
 255     case Type::IntegerTyID:
 256       // INTEGER: [width]
 257       Code = bitc::TYPE_CODE_INTEGER;
 258       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 259       break;
 260     case Type::PointerTyID: {
 261       PointerType *PTy = cast<PointerType>(T);
 262       // POINTER: [pointee type, address space]
 263       Code = bitc::TYPE_CODE_POINTER;
 264       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 265       unsigned AddressSpace = PTy->getAddressSpace();
 266       TypeVals.push_back(AddressSpace);
 267       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 268       break;
 269     }
 270     case Type::FunctionTyID: {
 271       FunctionType *FT = cast<FunctionType>(T);
 272       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 273       Code = bitc::TYPE_CODE_FUNCTION;
 274       TypeVals.push_back(FT->isVarArg());
 275       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 276       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 277       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 278         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 279       AbbrevToUse = FunctionAbbrev;
 280       break;
 281     }
 282     case Type::StructTyID: {
 283       StructType *ST = cast<StructType>(T);
 284       // STRUCT: [ispacked, eltty x N]
 285       TypeVals.push_back(ST->isPacked());
 286       // Output all of the element types.
 287       for (StructType::element_iterator I = ST->element_begin(),
 288            E = ST->element_end(); I != E; ++I)
 289         TypeVals.push_back(VE.getTypeID(*I));
 290
 291       if (ST->isAnonymous()) {
 292         Code = bitc::TYPE_CODE_STRUCT_ANON;
 293         AbbrevToUse = StructAnonAbbrev;
 294       } else {
 295         if (ST->isOpaque()) {
 296           Code = bitc::TYPE_CODE_OPAQUE;
 297         } else {
 298           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 299           AbbrevToUse = StructNamedAbbrev;
 300         }
 301
 302         // Emit the name if it is present.
 303         if (!ST->getName().empty())
 304           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 305                             StructNameAbbrev, Stream);
 306       }
 307       break;
 308     }
 309     case Type::ArrayTyID: {
 310       ArrayType *AT = cast<ArrayType>(T);
 311       // ARRAY: [numelts, eltty]
 312       Code = bitc::TYPE_CODE_ARRAY;
 313       TypeVals.push_back(AT->getNumElements());
 314       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 315       AbbrevToUse = ArrayAbbrev;
 316       break;
 317     }
 318     case Type::VectorTyID: {
 319       VectorType *VT = cast<VectorType>(T);
 320       // VECTOR [numelts, eltty]
 321       Code = bitc::TYPE_CODE_VECTOR;
 322       TypeVals.push_back(VT->getNumElements());
 323       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 324       break;
 325     }
 326     }
 327
 328     // Emit the finished record.
 329     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 330     TypeVals.clear();
 331   }
 332
 333   Stream.ExitBlock();
 334 }
 335
 336 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 337   switch (GV->getLinkage()) {
 338   default: llvm_unreachable("Invalid linkage!");
 339   case GlobalValue::ExternalLinkage:                 return 0;
 340   case GlobalValue::WeakAnyLinkage:                  return 1;
 341   case GlobalValue::AppendingLinkage:                return 2;
 342   case GlobalValue::InternalLinkage:                 return 3;
 343   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 344   case GlobalValue::DLLImportLinkage:                return 5;
 345   case GlobalValue::DLLExportLinkage:                return 6;
 346   case GlobalValue::ExternalWeakLinkage:             return 7;
 347   case GlobalValue::CommonLinkage:                   return 8;
 348   case GlobalValue::PrivateLinkage:                  return 9;
 349   case GlobalValue::WeakODRLinkage:                  return 10;
 350   case GlobalValue::LinkOnceODRLinkage:              return 11;
 351   case GlobalValue::AvailableExternallyLinkage:      return 12;
 352   case GlobalValue::LinkerPrivateLinkage:            return 13;
 353   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 354   case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
 355   }
 356 }
 357
 358 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 359   switch (GV->getVisibility()) {
 360   default: llvm_unreachable("Invalid visibility!");
 361   case GlobalValue::DefaultVisibility:   return 0;
 362   case GlobalValue::HiddenVisibility:    return 1;
 363   case GlobalValue::ProtectedVisibility: return 2;
 364   }
 365 }
 366
 367 // Emit top-level description of module, including target triple, inline asm,
 368 // descriptors for global variables, and function prototype info.
 369 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 370                             BitstreamWriter &Stream) {
 371   // Emit the list of dependent libraries for the Module.
 372   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 373     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 374
 375   // Emit various pieces of data attached to a module.
 376   if (!M->getTargetTriple().empty())
 377     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 378                       0/*TODO*/, Stream);
 379   if (!M->getDataLayout().empty())
 380     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 381                       0/*TODO*/, Stream);
 382   if (!M->getModuleInlineAsm().empty())
 383     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 384                       0/*TODO*/, Stream);
 385
 386   // Emit information about sections and GC, computing how many there are. Also
 387   // compute the maximum alignment value.
 388   std::map<std::string, unsigned> SectionMap;
 389   std::map<std::string, unsigned> GCMap;
 390   unsigned MaxAlignment = 0;
 391   unsigned MaxGlobalType = 0;
 392   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 393        GV != E; ++GV) {
 394     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 395     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 396
 397     if (!GV->hasSection()) continue;
 398     // Give section names unique ID's.
 399     unsigned &Entry = SectionMap[GV->getSection()];
 400     if (Entry != 0) continue;
 401     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 402                       0/*TODO*/, Stream);
 403     Entry = SectionMap.size();
 404   }
 405   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 406     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 407     if (F->hasSection()) {
 408       // Give section names unique ID's.
 409       unsigned &Entry = SectionMap[F->getSection()];
 410       if (!Entry) {
 411         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 412                           0/*TODO*/, Stream);
 413         Entry = SectionMap.size();
 414       }
 415     }
 416     if (F->hasGC()) {
 417       // Same for GC names.
 418       unsigned &Entry = GCMap[F->getGC()];
 419       if (!Entry) {
 420         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 421                           0/*TODO*/, Stream);
 422         Entry = GCMap.size();
 423       }
 424     }
 425   }
 426
 427   // Emit abbrev for globals, now that we know # sections and max alignment.
 428   unsigned SimpleGVarAbbrev = 0;
 429   if (!M->global_empty()) {
 430     // Add an abbrev for common globals with no visibility or thread localness.
 431     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 432     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 434                               Log2_32_Ceil(MaxGlobalType+1)));
 435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 438     if (MaxAlignment == 0)                                      // Alignment.
 439       Abbv->Add(BitCodeAbbrevOp(0));
 440     else {
 441       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 442       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 443                                Log2_32_Ceil(MaxEncAlignment+1)));
 444     }
 445     if (SectionMap.empty())                                    // Section.
 446       Abbv->Add(BitCodeAbbrevOp(0));
 447     else
 448       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 449                                Log2_32_Ceil(SectionMap.size()+1)));
 450     // Don't bother emitting vis + thread local.
 451     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 452   }
 453
 454   // Emit the global variable information.
 455   SmallVector<unsigned, 64> Vals;
 456   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 457        GV != E; ++GV) {
 458     unsigned AbbrevToUse = 0;
 459
 460     // GLOBALVAR: [type, isconst, initid,
 461     //             linkage, alignment, section, visibility, threadlocal,
 462     //             unnamed_addr]
 463     Vals.push_back(VE.getTypeID(GV->getType()));
 464     Vals.push_back(GV->isConstant());
 465     Vals.push_back(GV->isDeclaration() ? 0 :
 466                    (VE.getValueID(GV->getInitializer()) + 1));
 467     Vals.push_back(getEncodedLinkage(GV));
 468     Vals.push_back(Log2_32(GV->getAlignment())+1);
 469     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 470     if (GV->isThreadLocal() ||
 471         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 472         GV->hasUnnamedAddr()) {
 473       Vals.push_back(getEncodedVisibility(GV));
 474       Vals.push_back(GV->isThreadLocal());
 475       Vals.push_back(GV->hasUnnamedAddr());
 476     } else {
 477       AbbrevToUse = SimpleGVarAbbrev;
 478     }
 479
 480     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 481     Vals.clear();
 482   }
 483
 484   // Emit the function proto information.
 485   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 486     // FUNCTION:  [type, callingconv, isproto, paramattr,
 487     //             linkage, alignment, section, visibility, gc, unnamed_addr]
 488     Vals.push_back(VE.getTypeID(F->getType()));
 489     Vals.push_back(F->getCallingConv());
 490     Vals.push_back(F->isDeclaration());
 491     Vals.push_back(getEncodedLinkage(F));
 492     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 493     Vals.push_back(Log2_32(F->getAlignment())+1);
 494     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 495     Vals.push_back(getEncodedVisibility(F));
 496     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 497     Vals.push_back(F->hasUnnamedAddr());
 498
 499     unsigned AbbrevToUse = 0;
 500     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 501     Vals.clear();
 502   }
 503
 504   // Emit the alias information.
 505   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 506        AI != E; ++AI) {
 507     Vals.push_back(VE.getTypeID(AI->getType()));
 508     Vals.push_back(VE.getValueID(AI->getAliasee()));
 509     Vals.push_back(getEncodedLinkage(AI));
 510     Vals.push_back(getEncodedVisibility(AI));
 511     unsigned AbbrevToUse = 0;
 512     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 513     Vals.clear();
 514   }
 515 }
 516
 517 static uint64_t GetOptimizationFlags(const Value *V) {
 518   uint64_t Flags = 0;
 519
 520   if (const OverflowingBinaryOperator *OBO =
 521         dyn_cast<OverflowingBinaryOperator>(V)) {
 522     if (OBO->hasNoSignedWrap())
 523       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 524     if (OBO->hasNoUnsignedWrap())
 525       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 526   } else if (const PossiblyExactOperator *PEO =
 527                dyn_cast<PossiblyExactOperator>(V)) {
 528     if (PEO->isExact())
 529       Flags |= 1 << bitc::PEO_EXACT;
 530   }
 531
 532   return Flags;
 533 }
 534
 535 static void WriteMDNode(const MDNode *N,
 536                         const ValueEnumerator &VE,
 537                         BitstreamWriter &Stream,
 538                         SmallVector<uint64_t, 64> &Record) {
 539   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 540     if (N->getOperand(i)) {
 541       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 542       Record.push_back(VE.getValueID(N->getOperand(i)));
 543     } else {
 544       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 545       Record.push_back(0);
 546     }
 547   }
 548   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 549                                            bitc::METADATA_NODE;
 550   Stream.EmitRecord(MDCode, Record, 0);
 551   Record.clear();
 552 }
 553
 554 static void WriteModuleMetadata(const Module *M,
 555                                 const ValueEnumerator &VE,
 556                                 BitstreamWriter &Stream) {
 557   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 558   bool StartedMetadataBlock = false;
 559   unsigned MDSAbbrev = 0;
 560   SmallVector<uint64_t, 64> Record;
 561   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 562
 563     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 564       if (!N->isFunctionLocal() || !N->getFunction()) {
 565         if (!StartedMetadataBlock) {
 566           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 567           StartedMetadataBlock = true;
 568         }
 569         WriteMDNode(N, VE, Stream, Record);
 570       }
 571     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 572       if (!StartedMetadataBlock)  {
 573         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 574
 575         // Abbrev for METADATA_STRING.
 576         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 577         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 578         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 579         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 580         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 581         StartedMetadataBlock = true;
 582       }
 583
 584       // Code: [strchar x N]
 585       Record.append(MDS->begin(), MDS->end());
 586
 587       // Emit the finished record.
 588       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 589       Record.clear();
 590     }
 591   }
 592
 593   // Write named metadata.
 594   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 595        E = M->named_metadata_end(); I != E; ++I) {
 596     const NamedMDNode *NMD = I;
 597     if (!StartedMetadataBlock)  {
 598       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 599       StartedMetadataBlock = true;
 600     }
 601
 602     // Write name.
 603     StringRef Str = NMD->getName();
 604     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 605       Record.push_back(Str[i]);
 606     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 607     Record.clear();
 608
 609     // Write named metadata operands.
 610     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 611       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 612     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 613     Record.clear();
 614   }
 615
 616   if (StartedMetadataBlock)
 617     Stream.ExitBlock();
 618 }
 619
 620 static void WriteFunctionLocalMetadata(const Function &F,
 621                                        const ValueEnumerator &VE,
 622                                        BitstreamWriter &Stream) {
 623   bool StartedMetadataBlock = false;
 624   SmallVector<uint64_t, 64> Record;
 625   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
 626   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 627     if (const MDNode *N = Vals[i])
 628       if (N->isFunctionLocal() && N->getFunction() == &F) {
 629         if (!StartedMetadataBlock) {
 630           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 631           StartedMetadataBlock = true;
 632         }
 633         WriteMDNode(N, VE, Stream, Record);
 634       }
 635
 636   if (StartedMetadataBlock)
 637     Stream.ExitBlock();
 638 }
 639
 640 static void WriteMetadataAttachment(const Function &F,
 641                                     const ValueEnumerator &VE,
 642                                     BitstreamWriter &Stream) {
 643   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 644
 645   SmallVector<uint64_t, 64> Record;
 646
 647   // Write metadata attachments
 648   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 649   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 650
 651   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 652     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 653          I != E; ++I) {
 654       MDs.clear();
 655       I->getAllMetadataOtherThanDebugLoc(MDs);
 656
 657       // If no metadata, ignore instruction.
 658       if (MDs.empty()) continue;
 659
 660       Record.push_back(VE.getInstructionID(I));
 661
 662       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 663         Record.push_back(MDs[i].first);
 664         Record.push_back(VE.getValueID(MDs[i].second));
 665       }
 666       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 667       Record.clear();
 668     }
 669
 670   Stream.ExitBlock();
 671 }
 672
 673 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 674   SmallVector<uint64_t, 64> Record;
 675
 676   // Write metadata kinds
 677   // METADATA_KIND - [n x [id, name]]
 678   SmallVector<StringRef, 4> Names;
 679   M->getMDKindNames(Names);
 680
 681   if (Names.empty()) return;
 682
 683   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 684
 685   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 686     Record.push_back(MDKindID);
 687     StringRef KName = Names[MDKindID];
 688     Record.append(KName.begin(), KName.end());
 689
 690     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 691     Record.clear();
 692   }
 693
 694   Stream.ExitBlock();
 695 }
 696
 697 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 698                            const ValueEnumerator &VE,
 699                            BitstreamWriter &Stream, bool isGlobal) {
 700   if (FirstVal == LastVal) return;
 701
 702   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 703
 704   unsigned AggregateAbbrev = 0;
 705   unsigned String8Abbrev = 0;
 706   unsigned CString7Abbrev = 0;
 707   unsigned CString6Abbrev = 0;
 708   // If this is a constant pool for the module, emit module-specific abbrevs.
 709   if (isGlobal) {
 710     // Abbrev for CST_CODE_AGGREGATE.
 711     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 712     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 713     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 714     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 715     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 716
 717     // Abbrev for CST_CODE_STRING.
 718     Abbv = new BitCodeAbbrev();
 719     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 720     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 721     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 722     String8Abbrev = Stream.EmitAbbrev(Abbv);
 723     // Abbrev for CST_CODE_CSTRING.
 724     Abbv = new BitCodeAbbrev();
 725     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 726     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 727     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 728     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 729     // Abbrev for CST_CODE_CSTRING.
 730     Abbv = new BitCodeAbbrev();
 731     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 732     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 734     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 735   }
 736
 737   SmallVector<uint64_t, 64> Record;
 738
 739   const ValueEnumerator::ValueList &Vals = VE.getValues();
 740   Type *LastTy = 0;
 741   for (unsigned i = FirstVal; i != LastVal; ++i) {
 742     const Value *V = Vals[i].first;
 743     // If we need to switch types, do so now.
 744     if (V->getType() != LastTy) {
 745       LastTy = V->getType();
 746       Record.push_back(VE.getTypeID(LastTy));
 747       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 748                         CONSTANTS_SETTYPE_ABBREV);
 749       Record.clear();
 750     }
 751
 752     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 753       Record.push_back(unsigned(IA->hasSideEffects()) |
 754                        unsigned(IA->isAlignStack()) << 1);
 755
 756       // Add the asm string.
 757       const std::string &AsmStr = IA->getAsmString();
 758       Record.push_back(AsmStr.size());
 759       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 760         Record.push_back(AsmStr[i]);
 761
 762       // Add the constraint string.
 763       const std::string &ConstraintStr = IA->getConstraintString();
 764       Record.push_back(ConstraintStr.size());
 765       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 766         Record.push_back(ConstraintStr[i]);
 767       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 768       Record.clear();
 769       continue;
 770     }
 771     const Constant *C = cast<Constant>(V);
 772     unsigned Code = -1U;
 773     unsigned AbbrevToUse = 0;
 774     if (C->isNullValue()) {
 775       Code = bitc::CST_CODE_NULL;
 776     } else if (isa<UndefValue>(C)) {
 777       Code = bitc::CST_CODE_UNDEF;
 778     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 779       if (IV->getBitWidth() <= 64) {
 780         uint64_t V = IV->getSExtValue();
 781         if ((int64_t)V >= 0)
 782           Record.push_back(V << 1);
 783         else
 784           Record.push_back((-V << 1) | 1);
 785         Code = bitc::CST_CODE_INTEGER;
 786         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 787       } else {                             // Wide integers, > 64 bits in size.
 788         // We have an arbitrary precision integer value to write whose
 789         // bit width is > 64. However, in canonical unsigned integer
 790         // format it is likely that the high bits are going to be zero.
 791         // So, we only write the number of active words.
 792         unsigned NWords = IV->getValue().getActiveWords();
 793         const uint64_t *RawWords = IV->getValue().getRawData();
 794         for (unsigned i = 0; i != NWords; ++i) {
 795           int64_t V = RawWords[i];
 796           if (V >= 0)
 797             Record.push_back(V << 1);
 798           else
 799             Record.push_back((-V << 1) | 1);
 800         }
 801         Code = bitc::CST_CODE_WIDE_INTEGER;
 802       }
 803     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 804       Code = bitc::CST_CODE_FLOAT;
 805       Type *Ty = CFP->getType();
 806       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 807         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 808       } else if (Ty->isX86_FP80Ty()) {
 809         // api needed to prevent premature destruction
 810         // bits are not in the same order as a normal i80 APInt, compensate.
 811         APInt api = CFP->getValueAPF().bitcastToAPInt();
 812         const uint64_t *p = api.getRawData();
 813         Record.push_back((p[1] << 48) | (p[0] >> 16));
 814         Record.push_back(p[0] & 0xffffLL);
 815       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 816         APInt api = CFP->getValueAPF().bitcastToAPInt();
 817         const uint64_t *p = api.getRawData();
 818         Record.push_back(p[0]);
 819         Record.push_back(p[1]);
 820       } else {
 821         assert (0 && "Unknown FP type!");
 822       }
 823     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 824       const ConstantArray *CA = cast<ConstantArray>(C);
 825       // Emit constant strings specially.
 826       unsigned NumOps = CA->getNumOperands();
 827       // If this is a null-terminated string, use the denser CSTRING encoding.
 828       if (CA->getOperand(NumOps-1)->isNullValue()) {
 829         Code = bitc::CST_CODE_CSTRING;
 830         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 831       } else {
 832         Code = bitc::CST_CODE_STRING;
 833         AbbrevToUse = String8Abbrev;
 834       }
 835       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 836       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 837       for (unsigned i = 0; i != NumOps; ++i) {
 838         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 839         Record.push_back(V);
 840         isCStr7 &= (V & 128) == 0;
 841         if (isCStrChar6)
 842           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 843       }
 844
 845       if (isCStrChar6)
 846         AbbrevToUse = CString6Abbrev;
 847       else if (isCStr7)
 848         AbbrevToUse = CString7Abbrev;
 849     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 850                isa<ConstantVector>(V)) {
 851       Code = bitc::CST_CODE_AGGREGATE;
 852       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 853         Record.push_back(VE.getValueID(C->getOperand(i)));
 854       AbbrevToUse = AggregateAbbrev;
 855     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 856       switch (CE->getOpcode()) {
 857       default:
 858         if (Instruction::isCast(CE->getOpcode())) {
 859           Code = bitc::CST_CODE_CE_CAST;
 860           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 861           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 862           Record.push_back(VE.getValueID(C->getOperand(0)));
 863           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 864         } else {
 865           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 866           Code = bitc::CST_CODE_CE_BINOP;
 867           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 868           Record.push_back(VE.getValueID(C->getOperand(0)));
 869           Record.push_back(VE.getValueID(C->getOperand(1)));
 870           uint64_t Flags = GetOptimizationFlags(CE);
 871           if (Flags != 0)
 872             Record.push_back(Flags);
 873         }
 874         break;
 875       case Instruction::GetElementPtr:
 876         Code = bitc::CST_CODE_CE_GEP;
 877         if (cast<GEPOperator>(C)->isInBounds())
 878           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 879         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 880           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 881           Record.push_back(VE.getValueID(C->getOperand(i)));
 882         }
 883         break;
 884       case Instruction::Select:
 885         Code = bitc::CST_CODE_CE_SELECT;
 886         Record.push_back(VE.getValueID(C->getOperand(0)));
 887         Record.push_back(VE.getValueID(C->getOperand(1)));
 888         Record.push_back(VE.getValueID(C->getOperand(2)));
 889         break;
 890       case Instruction::ExtractElement:
 891         Code = bitc::CST_CODE_CE_EXTRACTELT;
 892         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 893         Record.push_back(VE.getValueID(C->getOperand(0)));
 894         Record.push_back(VE.getValueID(C->getOperand(1)));
 895         break;
 896       case Instruction::InsertElement:
 897         Code = bitc::CST_CODE_CE_INSERTELT;
 898         Record.push_back(VE.getValueID(C->getOperand(0)));
 899         Record.push_back(VE.getValueID(C->getOperand(1)));
 900         Record.push_back(VE.getValueID(C->getOperand(2)));
 901         break;
 902       case Instruction::ShuffleVector:
 903         // If the return type and argument types are the same, this is a
 904         // standard shufflevector instruction.  If the types are different,
 905         // then the shuffle is widening or truncating the input vectors, and
 906         // the argument type must also be encoded.
 907         if (C->getType() == C->getOperand(0)->getType()) {
 908           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 909         } else {
 910           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 911           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 912         }
 913         Record.push_back(VE.getValueID(C->getOperand(0)));
 914         Record.push_back(VE.getValueID(C->getOperand(1)));
 915         Record.push_back(VE.getValueID(C->getOperand(2)));
 916         break;
 917       case Instruction::ICmp:
 918       case Instruction::FCmp:
 919         Code = bitc::CST_CODE_CE_CMP;
 920         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 921         Record.push_back(VE.getValueID(C->getOperand(0)));
 922         Record.push_back(VE.getValueID(C->getOperand(1)));
 923         Record.push_back(CE->getPredicate());
 924         break;
 925       }
 926     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 927       Code = bitc::CST_CODE_BLOCKADDRESS;
 928       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 929       Record.push_back(VE.getValueID(BA->getFunction()));
 930       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 931     } else {
 932 #ifndef NDEBUG
 933       C->dump();
 934 #endif
 935       llvm_unreachable("Unknown constant!");
 936     }
 937     Stream.EmitRecord(Code, Record, AbbrevToUse);
 938     Record.clear();
 939   }
 940
 941   Stream.ExitBlock();
 942 }
 943
 944 static void WriteModuleConstants(const ValueEnumerator &VE,
 945                                  BitstreamWriter &Stream) {
 946   const ValueEnumerator::ValueList &Vals = VE.getValues();
 947
 948   // Find the first constant to emit, which is the first non-globalvalue value.
 949   // We know globalvalues have been emitted by WriteModuleInfo.
 950   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 951     if (!isa<GlobalValue>(Vals[i].first)) {
 952       WriteConstants(i, Vals.size(), VE, Stream, true);
 953       return;
 954     }
 955   }
 956 }
 957
 958 /// PushValueAndType - The file has to encode both the value and type id for
 959 /// many values, because we need to know what type to create for forward
 960 /// references.  However, most operands are not forward references, so this type
 961 /// field is not needed.
 962 ///
 963 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 964 /// instruction ID, then it is a forward reference, and it also includes the
 965 /// type ID.
 966 static bool PushValueAndType(const Value *V, unsigned InstID,
 967                              SmallVector<unsigned, 64> &Vals,
 968                              ValueEnumerator &VE) {
 969   unsigned ValID = VE.getValueID(V);
 970   Vals.push_back(ValID);
 971   if (ValID >= InstID) {
 972     Vals.push_back(VE.getTypeID(V->getType()));
 973     return true;
 974   }
 975   return false;
 976 }
 977
 978 /// WriteInstruction - Emit an instruction to the specified stream.
 979 static void WriteInstruction(const Instruction &I, unsigned InstID,
 980                              ValueEnumerator &VE, BitstreamWriter &Stream,
 981                              SmallVector<unsigned, 64> &Vals) {
 982   unsigned Code = 0;
 983   unsigned AbbrevToUse = 0;
 984   VE.setInstructionID(&I);
 985   switch (I.getOpcode()) {
 986   default:
 987     if (Instruction::isCast(I.getOpcode())) {
 988       Code = bitc::FUNC_CODE_INST_CAST;
 989       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 990         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 991       Vals.push_back(VE.getTypeID(I.getType()));
 992       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 993     } else {
 994       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 995       Code = bitc::FUNC_CODE_INST_BINOP;
 996       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 997         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 998       Vals.push_back(VE.getValueID(I.getOperand(1)));
 999       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1000       uint64_t Flags = GetOptimizationFlags(&I);
1001       if (Flags != 0) {
1002         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1003           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1004         Vals.push_back(Flags);
1005       }
1006     }
1007     break;
1008
1009   case Instruction::GetElementPtr:
1010     Code = bitc::FUNC_CODE_INST_GEP;
1011     if (cast<GEPOperator>(&I)->isInBounds())
1012       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1013     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1014       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1015     break;
1016   case Instruction::ExtractValue: {
1017     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1018     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1019     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1020     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1021       Vals.push_back(*i);
1022     break;
1023   }
1024   case Instruction::InsertValue: {
1025     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1026     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1027     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1028     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1029     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1030       Vals.push_back(*i);
1031     break;
1032   }
1033   case Instruction::Select:
1034     Code = bitc::FUNC_CODE_INST_VSELECT;
1035     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1036     Vals.push_back(VE.getValueID(I.getOperand(2)));
1037     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1038     break;
1039   case Instruction::ExtractElement:
1040     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1041     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1042     Vals.push_back(VE.getValueID(I.getOperand(1)));
1043     break;
1044   case Instruction::InsertElement:
1045     Code = bitc::FUNC_CODE_INST_INSERTELT;
1046     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1047     Vals.push_back(VE.getValueID(I.getOperand(1)));
1048     Vals.push_back(VE.getValueID(I.getOperand(2)));
1049     break;
1050   case Instruction::ShuffleVector:
1051     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1052     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1053     Vals.push_back(VE.getValueID(I.getOperand(1)));
1054     Vals.push_back(VE.getValueID(I.getOperand(2)));
1055     break;
1056   case Instruction::ICmp:
1057   case Instruction::FCmp:
1058     // compare returning Int1Ty or vector of Int1Ty
1059     Code = bitc::FUNC_CODE_INST_CMP2;
1060     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1061     Vals.push_back(VE.getValueID(I.getOperand(1)));
1062     Vals.push_back(cast<CmpInst>(I).getPredicate());
1063     break;
1064
1065   case Instruction::Ret:
1066     {
1067       Code = bitc::FUNC_CODE_INST_RET;
1068       unsigned NumOperands = I.getNumOperands();
1069       if (NumOperands == 0)
1070         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1071       else if (NumOperands == 1) {
1072         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1073           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1074       } else {
1075         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1076           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1077       }
1078     }
1079     break;
1080   case Instruction::Br:
1081     {
1082       Code = bitc::FUNC_CODE_INST_BR;
1083       BranchInst &II = cast<BranchInst>(I);
1084       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1085       if (II.isConditional()) {
1086         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1087         Vals.push_back(VE.getValueID(II.getCondition()));
1088       }
1089     }
1090     break;
1091   case Instruction::Switch:
1092     Code = bitc::FUNC_CODE_INST_SWITCH;
1093     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1094     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1095       Vals.push_back(VE.getValueID(I.getOperand(i)));
1096     break;
1097   case Instruction::IndirectBr:
1098     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1099     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1100     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1101       Vals.push_back(VE.getValueID(I.getOperand(i)));
1102     break;
1103
1104   case Instruction::Invoke: {
1105     const InvokeInst *II = cast<InvokeInst>(&I);
1106     const Value *Callee(II->getCalledValue());
1107     PointerType *PTy = cast<PointerType>(Callee->getType());
1108     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1109     Code = bitc::FUNC_CODE_INST_INVOKE;
1110
1111     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1112     Vals.push_back(II->getCallingConv());
1113     Vals.push_back(VE.getValueID(II->getNormalDest()));
1114     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1115     PushValueAndType(Callee, InstID, Vals, VE);
1116
1117     // Emit value #'s for the fixed parameters.
1118     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1119       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1120
1121     // Emit type/value pairs for varargs params.
1122     if (FTy->isVarArg()) {
1123       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1124            i != e; ++i)
1125         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1126     }
1127     break;
1128   }
1129   case Instruction::Unwind:
1130     Code = bitc::FUNC_CODE_INST_UNWIND;
1131     break;
1132   case Instruction::Unreachable:
1133     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1134     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1135     break;
1136
1137   case Instruction::PHI: {
1138     const PHINode &PN = cast<PHINode>(I);
1139     Code = bitc::FUNC_CODE_INST_PHI;
1140     Vals.push_back(VE.getTypeID(PN.getType()));
1141     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1142       Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1143       Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1144     }
1145     break;
1146   }
1147
1148   case Instruction::Alloca:
1149     Code = bitc::FUNC_CODE_INST_ALLOCA;
1150     Vals.push_back(VE.getTypeID(I.getType()));
1151     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1152     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1153     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1154     break;
1155
1156   case Instruction::Load:
1157     Code = bitc::FUNC_CODE_INST_LOAD;
1158     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1159       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1160
1161     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1162     Vals.push_back(cast<LoadInst>(I).isVolatile());
1163     break;
1164   case Instruction::Store:
1165     Code = bitc::FUNC_CODE_INST_STORE;
1166     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1167     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1168     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1169     Vals.push_back(cast<StoreInst>(I).isVolatile());
1170     break;
1171   case Instruction::Fence:
1172     Code = bitc::FUNC_CODE_INST_FENCE;
1173     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1174     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1175     break;
1176   case Instruction::Call: {
1177     const CallInst &CI = cast<CallInst>(I);
1178     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1179     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1180
1181     Code = bitc::FUNC_CODE_INST_CALL;
1182
1183     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1184     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1185     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1186
1187     // Emit value #'s for the fixed parameters.
1188     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1189       Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1190
1191     // Emit type/value pairs for varargs params.
1192     if (FTy->isVarArg()) {
1193       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1194            i != e; ++i)
1195         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1196     }
1197     break;
1198   }
1199   case Instruction::VAArg:
1200     Code = bitc::FUNC_CODE_INST_VAARG;
1201     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1202     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1203     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1204     break;
1205   }
1206
1207   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1208   Vals.clear();
1209 }
1210
1211 // Emit names for globals/functions etc.
1212 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1213                                   const ValueEnumerator &VE,
1214                                   BitstreamWriter &Stream) {
1215   if (VST.empty()) return;
1216   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1217
1218   // FIXME: Set up the abbrev, we know how many values there are!
1219   // FIXME: We know if the type names can use 7-bit ascii.
1220   SmallVector<unsigned, 64> NameVals;
1221
1222   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1223        SI != SE; ++SI) {
1224
1225     const ValueName &Name = *SI;
1226
1227     // Figure out the encoding to use for the name.
1228     bool is7Bit = true;
1229     bool isChar6 = true;
1230     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1231          C != E; ++C) {
1232       if (isChar6)
1233         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1234       if ((unsigned char)*C & 128) {
1235         is7Bit = false;
1236         break;  // don't bother scanning the rest.
1237       }
1238     }
1239
1240     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1241
1242     // VST_ENTRY:   [valueid, namechar x N]
1243     // VST_BBENTRY: [bbid, namechar x N]
1244     unsigned Code;
1245     if (isa<BasicBlock>(SI->getValue())) {
1246       Code = bitc::VST_CODE_BBENTRY;
1247       if (isChar6)
1248         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1249     } else {
1250       Code = bitc::VST_CODE_ENTRY;
1251       if (isChar6)
1252         AbbrevToUse = VST_ENTRY_6_ABBREV;
1253       else if (is7Bit)
1254         AbbrevToUse = VST_ENTRY_7_ABBREV;
1255     }
1256
1257     NameVals.push_back(VE.getValueID(SI->getValue()));
1258     for (const char *P = Name.getKeyData(),
1259          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1260       NameVals.push_back((unsigned char)*P);
1261
1262     // Emit the finished record.
1263     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1264     NameVals.clear();
1265   }
1266   Stream.ExitBlock();
1267 }
1268
1269 /// WriteFunction - Emit a function body to the module stream.
1270 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1271                           BitstreamWriter &Stream) {
1272   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1273   VE.incorporateFunction(F);
1274
1275   SmallVector<unsigned, 64> Vals;
1276
1277   // Emit the number of basic blocks, so the reader can create them ahead of
1278   // time.
1279   Vals.push_back(VE.getBasicBlocks().size());
1280   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1281   Vals.clear();
1282
1283   // If there are function-local constants, emit them now.
1284   unsigned CstStart, CstEnd;
1285   VE.getFunctionConstantRange(CstStart, CstEnd);
1286   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1287
1288   // If there is function-local metadata, emit it now.
1289   WriteFunctionLocalMetadata(F, VE, Stream);
1290
1291   // Keep a running idea of what the instruction ID is.
1292   unsigned InstID = CstEnd;
1293
1294   bool NeedsMetadataAttachment = false;
1295
1296   DebugLoc LastDL;
1297
1298   // Finally, emit all the instructions, in order.
1299   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1300     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1301          I != E; ++I) {
1302       WriteInstruction(*I, InstID, VE, Stream, Vals);
1303
1304       if (!I->getType()->isVoidTy())
1305         ++InstID;
1306
1307       // If the instruction has metadata, write a metadata attachment later.
1308       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1309
1310       // If the instruction has a debug location, emit it.
1311       DebugLoc DL = I->getDebugLoc();
1312       if (DL.isUnknown()) {
1313         // nothing todo.
1314       } else if (DL == LastDL) {
1315         // Just repeat the same debug loc as last time.
1316         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1317       } else {
1318         MDNode *Scope, *IA;
1319         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1320
1321         Vals.push_back(DL.getLine());
1322         Vals.push_back(DL.getCol());
1323         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1324         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1325         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1326         Vals.clear();
1327
1328         LastDL = DL;
1329       }
1330     }
1331
1332   // Emit names for all the instructions etc.
1333   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1334
1335   if (NeedsMetadataAttachment)
1336     WriteMetadataAttachment(F, VE, Stream);
1337   VE.purgeFunction();
1338   Stream.ExitBlock();
1339 }
1340
1341 // Emit blockinfo, which defines the standard abbreviations etc.
1342 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1343   // We only want to emit block info records for blocks that have multiple
1344   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1345   // blocks can defined their abbrevs inline.
1346   Stream.EnterBlockInfoBlock(2);
1347
1348   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1349     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1354     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1355                                    Abbv) != VST_ENTRY_8_ABBREV)
1356       llvm_unreachable("Unexpected abbrev ordering!");
1357   }
1358
1359   { // 7-bit fixed width VST_ENTRY strings.
1360     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1361     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1362     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1365     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1366                                    Abbv) != VST_ENTRY_7_ABBREV)
1367       llvm_unreachable("Unexpected abbrev ordering!");
1368   }
1369   { // 6-bit char6 VST_ENTRY strings.
1370     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1371     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1375     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1376                                    Abbv) != VST_ENTRY_6_ABBREV)
1377       llvm_unreachable("Unexpected abbrev ordering!");
1378   }
1379   { // 6-bit char6 VST_BBENTRY strings.
1380     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1381     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1385     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1386                                    Abbv) != VST_BBENTRY_6_ABBREV)
1387       llvm_unreachable("Unexpected abbrev ordering!");
1388   }
1389
1390
1391
1392   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1393     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1394     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1396                               Log2_32_Ceil(VE.getTypes().size()+1)));
1397     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1398                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1399       llvm_unreachable("Unexpected abbrev ordering!");
1400   }
1401
1402   { // INTEGER abbrev for CONSTANTS_BLOCK.
1403     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1404     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1406     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1407                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1408       llvm_unreachable("Unexpected abbrev ordering!");
1409   }
1410
1411   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1412     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1413     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1416                               Log2_32_Ceil(VE.getTypes().size()+1)));
1417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1418
1419     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1420                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1421       llvm_unreachable("Unexpected abbrev ordering!");
1422   }
1423   { // NULL abbrev for CONSTANTS_BLOCK.
1424     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1425     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1426     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1427                                    Abbv) != CONSTANTS_NULL_Abbrev)
1428       llvm_unreachable("Unexpected abbrev ordering!");
1429   }
1430
1431   // FIXME: This should only use space for first class types!
1432
1433   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1434     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1435     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1439     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1440                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1441       llvm_unreachable("Unexpected abbrev ordering!");
1442   }
1443   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1444     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1445     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1449     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1450                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1451       llvm_unreachable("Unexpected abbrev ordering!");
1452   }
1453   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1454     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1455     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1459     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1460     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1461                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1462       llvm_unreachable("Unexpected abbrev ordering!");
1463   }
1464   { // INST_CAST abbrev for FUNCTION_BLOCK.
1465     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1466     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1469                               Log2_32_Ceil(VE.getTypes().size()+1)));
1470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1471     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1472                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1473       llvm_unreachable("Unexpected abbrev ordering!");
1474   }
1475
1476   { // INST_RET abbrev for FUNCTION_BLOCK.
1477     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1478     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1479     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1480                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1481       llvm_unreachable("Unexpected abbrev ordering!");
1482   }
1483   { // INST_RET abbrev for FUNCTION_BLOCK.
1484     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1485     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1487     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1488                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1489       llvm_unreachable("Unexpected abbrev ordering!");
1490   }
1491   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1492     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1493     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1494     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1495                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1496       llvm_unreachable("Unexpected abbrev ordering!");
1497   }
1498
1499   Stream.ExitBlock();
1500 }
1501
1502
1503 /// WriteModule - Emit the specified module to the bitstream.
1504 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1505   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1506
1507   // Emit the version number if it is non-zero.
1508   if (CurVersion) {
1509     SmallVector<unsigned, 1> Vals;
1510     Vals.push_back(CurVersion);
1511     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1512   }
1513
1514   // Analyze the module, enumerating globals, functions, etc.
1515   ValueEnumerator VE(M);
1516
1517   // Emit blockinfo, which defines the standard abbreviations etc.
1518   WriteBlockInfo(VE, Stream);
1519
1520   // Emit information about parameter attributes.
1521   WriteAttributeTable(VE, Stream);
1522
1523   // Emit information describing all of the types in the module.
1524   WriteTypeTable(VE, Stream);
1525
1526   // Emit top-level description of module, including target triple, inline asm,
1527   // descriptors for global variables, and function prototype info.
1528   WriteModuleInfo(M, VE, Stream);
1529
1530   // Emit constants.
1531   WriteModuleConstants(VE, Stream);
1532
1533   // Emit metadata.
1534   WriteModuleMetadata(M, VE, Stream);
1535
1536   // Emit function bodies.
1537   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1538     if (!F->isDeclaration())
1539       WriteFunction(*F, VE, Stream);
1540
1541   // Emit metadata.
1542   WriteModuleMetadataStore(M, Stream);
1543
1544   // Emit names for globals/functions etc.
1545   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1546
1547   Stream.ExitBlock();
1548 }
1549
1550 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1551 /// header and trailer to make it compatible with the system archiver.  To do
1552 /// this we emit the following header, and then emit a trailer that pads the
1553 /// file out to be a multiple of 16 bytes.
1554 ///
1555 /// struct bc_header {
1556 ///   uint32_t Magic;         // 0x0B17C0DE
1557 ///   uint32_t Version;       // Version, currently always 0.
1558 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1559 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1560 ///   uint32_t CPUType;       // CPU specifier.
1561 ///   ... potentially more later ...
1562 /// };
1563 enum {
1564   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1565   DarwinBCHeaderSize = 5*4
1566 };
1567
1568 static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
1569   unsigned CPUType = ~0U;
1570
1571   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1572   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1573   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1574   // specific constants here because they are implicitly part of the Darwin ABI.
1575   enum {
1576     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1577     DARWIN_CPU_TYPE_X86        = 7,
1578     DARWIN_CPU_TYPE_ARM        = 12,
1579     DARWIN_CPU_TYPE_POWERPC    = 18
1580   };
1581
1582   Triple::ArchType Arch = TT.getArch();
1583   if (Arch == Triple::x86_64)
1584     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1585   else if (Arch == Triple::x86)
1586     CPUType = DARWIN_CPU_TYPE_X86;
1587   else if (Arch == Triple::ppc)
1588     CPUType = DARWIN_CPU_TYPE_POWERPC;
1589   else if (Arch == Triple::ppc64)
1590     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1591   else if (Arch == Triple::arm || Arch == Triple::thumb)
1592     CPUType = DARWIN_CPU_TYPE_ARM;
1593
1594   // Traditional Bitcode starts after header.
1595   unsigned BCOffset = DarwinBCHeaderSize;
1596
1597   Stream.Emit(0x0B17C0DE, 32);
1598   Stream.Emit(0         , 32);  // Version.
1599   Stream.Emit(BCOffset  , 32);
1600   Stream.Emit(0         , 32);  // Filled in later.
1601   Stream.Emit(CPUType   , 32);
1602 }
1603
1604 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1605 /// finalize the header.
1606 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1607   // Update the size field in the header.
1608   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1609
1610   // If the file is not a multiple of 16 bytes, insert dummy padding.
1611   while (BufferSize & 15) {
1612     Stream.Emit(0, 8);
1613     ++BufferSize;
1614   }
1615 }
1616
1617
1618 /// WriteBitcodeToFile - Write the specified module to the specified output
1619 /// stream.
1620 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1621   std::vector<unsigned char> Buffer;
1622   BitstreamWriter Stream(Buffer);
1623
1624   Buffer.reserve(256*1024);
1625
1626   WriteBitcodeToStream( M, Stream );
1627
1628   // Write the generated bitstream to "Out".
1629   Out.write((char*)&Buffer.front(), Buffer.size());
1630 }
1631
1632 /// WriteBitcodeToStream - Write the specified module to the specified output
1633 /// stream.
1634 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1635   // If this is darwin or another generic macho target, emit a file header and
1636   // trailer if needed.
1637   Triple TT(M->getTargetTriple());
1638   if (TT.isOSDarwin())
1639     EmitDarwinBCHeader(Stream, TT);
1640
1641   // Emit the file header.
1642   Stream.Emit((unsigned)'B', 8);
1643   Stream.Emit((unsigned)'C', 8);
1644   Stream.Emit(0x0, 4);
1645   Stream.Emit(0xC, 4);
1646   Stream.Emit(0xE, 4);
1647   Stream.Emit(0xD, 4);
1648
1649   // Emit the module.
1650   WriteModule(M, Stream);
1651
1652   if (TT.isOSDarwin())
1653     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1654 }