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 "ValueEnumerator.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Bitcode/BitstreamWriter.h"
  18 #include "llvm/Bitcode/LLVMBitCodes.h"
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DerivedTypes.h"
  21 #include "llvm/IR/InlineAsm.h"
  22 #include "llvm/IR/Instructions.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/IR/Operator.h"
  25 #include "llvm/IR/ValueSymbolTable.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/Program.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include <cctype>
  32 #include <map>
  33 using namespace llvm;
  34
  35 static cl::opt<bool>
  36 EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
  37                               cl::desc("Turn on experimental support for "
  38                                        "use-list order preservation."),
  39                               cl::init(false), cl::Hidden);
  40
  41 /// These are manifest constants used by the bitcode writer. They do not need to
  42 /// be kept in sync with the reader, but need to be consistent within this file.
  43 enum {
  44   // VALUE_SYMTAB_BLOCK abbrev id's.
  45   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  46   VST_ENTRY_7_ABBREV,
  47   VST_ENTRY_6_ABBREV,
  48   VST_BBENTRY_6_ABBREV,
  49
  50   // CONSTANTS_BLOCK abbrev id's.
  51   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  52   CONSTANTS_INTEGER_ABBREV,
  53   CONSTANTS_CE_CAST_Abbrev,
  54   CONSTANTS_NULL_Abbrev,
  55
  56   // FUNCTION_BLOCK abbrev id's.
  57   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  58   FUNCTION_INST_BINOP_ABBREV,
  59   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  60   FUNCTION_INST_CAST_ABBREV,
  61   FUNCTION_INST_RET_VOID_ABBREV,
  62   FUNCTION_INST_RET_VAL_ABBREV,
  63   FUNCTION_INST_UNREACHABLE_ABBREV
  64 };
  65
  66 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  67   switch (Opcode) {
  68   default: llvm_unreachable("Unknown cast instruction!");
  69   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  70   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  71   case Instruction::SExt    : return bitc::CAST_SEXT;
  72   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  73   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  74   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  75   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  76   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  77   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  78   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  79   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  80   case Instruction::BitCast : return bitc::CAST_BITCAST;
  81   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  82   }
  83 }
  84
  85 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  86   switch (Opcode) {
  87   default: llvm_unreachable("Unknown binary instruction!");
  88   case Instruction::Add:
  89   case Instruction::FAdd: return bitc::BINOP_ADD;
  90   case Instruction::Sub:
  91   case Instruction::FSub: return bitc::BINOP_SUB;
  92   case Instruction::Mul:
  93   case Instruction::FMul: return bitc::BINOP_MUL;
  94   case Instruction::UDiv: return bitc::BINOP_UDIV;
  95   case Instruction::FDiv:
  96   case Instruction::SDiv: return bitc::BINOP_SDIV;
  97   case Instruction::URem: return bitc::BINOP_UREM;
  98   case Instruction::FRem:
  99   case Instruction::SRem: return bitc::BINOP_SREM;
 100   case Instruction::Shl:  return bitc::BINOP_SHL;
 101   case Instruction::LShr: return bitc::BINOP_LSHR;
 102   case Instruction::AShr: return bitc::BINOP_ASHR;
 103   case Instruction::And:  return bitc::BINOP_AND;
 104   case Instruction::Or:   return bitc::BINOP_OR;
 105   case Instruction::Xor:  return bitc::BINOP_XOR;
 106   }
 107 }
 108
 109 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 110   switch (Op) {
 111   default: llvm_unreachable("Unknown RMW operation!");
 112   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 113   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 114   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 115   case AtomicRMWInst::And: return bitc::RMW_AND;
 116   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 117   case AtomicRMWInst::Or: return bitc::RMW_OR;
 118   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 119   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 120   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 121   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 122   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 123   }
 124 }
 125
 126 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 127   switch (Ordering) {
 128   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 129   case Unordered: return bitc::ORDERING_UNORDERED;
 130   case Monotonic: return bitc::ORDERING_MONOTONIC;
 131   case Acquire: return bitc::ORDERING_ACQUIRE;
 132   case Release: return bitc::ORDERING_RELEASE;
 133   case AcquireRelease: return bitc::ORDERING_ACQREL;
 134   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 135   }
 136   llvm_unreachable("Invalid ordering");
 137 }
 138
 139 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 140   switch (SynchScope) {
 141   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 142   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 143   }
 144   llvm_unreachable("Invalid synch scope");
 145 }
 146
 147 static void WriteStringRecord(unsigned Code, StringRef Str,
 148                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 149   SmallVector<unsigned, 64> Vals;
 150
 151   // Code: [strchar x N]
 152   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 153     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 154       AbbrevToUse = 0;
 155     Vals.push_back(Str[i]);
 156   }
 157
 158   // Emit the finished record.
 159   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 160 }
 161
 162 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 163   switch (Kind) {
 164   case Attribute::Alignment:
 165     return bitc::ATTR_KIND_ALIGNMENT;
 166   case Attribute::AlwaysInline:
 167     return bitc::ATTR_KIND_ALWAYS_INLINE;
 168   case Attribute::Builtin:
 169     return bitc::ATTR_KIND_BUILTIN;
 170   case Attribute::ByVal:
 171     return bitc::ATTR_KIND_BY_VAL;
 172   case Attribute::InAlloca:
 173     return bitc::ATTR_KIND_IN_ALLOCA;
 174   case Attribute::Cold:
 175     return bitc::ATTR_KIND_COLD;
 176   case Attribute::InlineHint:
 177     return bitc::ATTR_KIND_INLINE_HINT;
 178   case Attribute::InReg:
 179     return bitc::ATTR_KIND_IN_REG;
 180   case Attribute::MinSize:
 181     return bitc::ATTR_KIND_MIN_SIZE;
 182   case Attribute::Naked:
 183     return bitc::ATTR_KIND_NAKED;
 184   case Attribute::Nest:
 185     return bitc::ATTR_KIND_NEST;
 186   case Attribute::NoAlias:
 187     return bitc::ATTR_KIND_NO_ALIAS;
 188   case Attribute::NoBuiltin:
 189     return bitc::ATTR_KIND_NO_BUILTIN;
 190   case Attribute::NoCapture:
 191     return bitc::ATTR_KIND_NO_CAPTURE;
 192   case Attribute::NoDuplicate:
 193     return bitc::ATTR_KIND_NO_DUPLICATE;
 194   case Attribute::NoImplicitFloat:
 195     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 196   case Attribute::NoInline:
 197     return bitc::ATTR_KIND_NO_INLINE;
 198   case Attribute::NonLazyBind:
 199     return bitc::ATTR_KIND_NON_LAZY_BIND;
 200   case Attribute::NoRedZone:
 201     return bitc::ATTR_KIND_NO_RED_ZONE;
 202   case Attribute::NoReturn:
 203     return bitc::ATTR_KIND_NO_RETURN;
 204   case Attribute::NoUnwind:
 205     return bitc::ATTR_KIND_NO_UNWIND;
 206   case Attribute::OptimizeForSize:
 207     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 208   case Attribute::OptimizeNone:
 209     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 210   case Attribute::ReadNone:
 211     return bitc::ATTR_KIND_READ_NONE;
 212   case Attribute::ReadOnly:
 213     return bitc::ATTR_KIND_READ_ONLY;
 214   case Attribute::Returned:
 215     return bitc::ATTR_KIND_RETURNED;
 216   case Attribute::ReturnsTwice:
 217     return bitc::ATTR_KIND_RETURNS_TWICE;
 218   case Attribute::SExt:
 219     return bitc::ATTR_KIND_S_EXT;
 220   case Attribute::StackAlignment:
 221     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 222   case Attribute::StackProtect:
 223     return bitc::ATTR_KIND_STACK_PROTECT;
 224   case Attribute::StackProtectReq:
 225     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 226   case Attribute::StackProtectStrong:
 227     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 228   case Attribute::StructRet:
 229     return bitc::ATTR_KIND_STRUCT_RET;
 230   case Attribute::SanitizeAddress:
 231     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 232   case Attribute::SanitizeThread:
 233     return bitc::ATTR_KIND_SANITIZE_THREAD;
 234   case Attribute::SanitizeMemory:
 235     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 236   case Attribute::UWTable:
 237     return bitc::ATTR_KIND_UW_TABLE;
 238   case Attribute::ZExt:
 239     return bitc::ATTR_KIND_Z_EXT;
 240   case Attribute::EndAttrKinds:
 241     llvm_unreachable("Can not encode end-attribute kinds marker.");
 242   case Attribute::None:
 243     llvm_unreachable("Can not encode none-attribute.");
 244   }
 245
 246   llvm_unreachable("Trying to encode unknown attribute");
 247 }
 248
 249 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 250                                      BitstreamWriter &Stream) {
 251   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 252   if (AttrGrps.empty()) return;
 253
 254   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 255
 256   SmallVector<uint64_t, 64> Record;
 257   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 258     AttributeSet AS = AttrGrps[i];
 259     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 260       AttributeSet A = AS.getSlotAttributes(i);
 261
 262       Record.push_back(VE.getAttributeGroupID(A));
 263       Record.push_back(AS.getSlotIndex(i));
 264
 265       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 266            I != E; ++I) {
 267         Attribute Attr = *I;
 268         if (Attr.isEnumAttribute()) {
 269           Record.push_back(0);
 270           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 271         } else if (Attr.isAlignAttribute()) {
 272           Record.push_back(1);
 273           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 274           Record.push_back(Attr.getValueAsInt());
 275         } else {
 276           StringRef Kind = Attr.getKindAsString();
 277           StringRef Val = Attr.getValueAsString();
 278
 279           Record.push_back(Val.empty() ? 3 : 4);
 280           Record.append(Kind.begin(), Kind.end());
 281           Record.push_back(0);
 282           if (!Val.empty()) {
 283             Record.append(Val.begin(), Val.end());
 284             Record.push_back(0);
 285           }
 286         }
 287       }
 288
 289       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 290       Record.clear();
 291     }
 292   }
 293
 294   Stream.ExitBlock();
 295 }
 296
 297 static void WriteAttributeTable(const ValueEnumerator &VE,
 298                                 BitstreamWriter &Stream) {
 299   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 300   if (Attrs.empty()) return;
 301
 302   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 303
 304   SmallVector<uint64_t, 64> Record;
 305   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 306     const AttributeSet &A = Attrs[i];
 307     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 308       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 309
 310     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 311     Record.clear();
 312   }
 313
 314   Stream.ExitBlock();
 315 }
 316
 317 /// WriteTypeTable - Write out the type table for a module.
 318 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 319   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 320
 321   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 322   SmallVector<uint64_t, 64> TypeVals;
 323
 324   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 325
 326   // Abbrev for TYPE_CODE_POINTER.
 327   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 328   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 330   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 331   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 332
 333   // Abbrev for TYPE_CODE_FUNCTION.
 334   Abbv = new BitCodeAbbrev();
 335   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 337   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 339
 340   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 341
 342   // Abbrev for TYPE_CODE_STRUCT_ANON.
 343   Abbv = new BitCodeAbbrev();
 344   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 346   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 348
 349   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 350
 351   // Abbrev for TYPE_CODE_STRUCT_NAME.
 352   Abbv = new BitCodeAbbrev();
 353   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 356   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 357
 358   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 359   Abbv = new BitCodeAbbrev();
 360   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 364
 365   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 366
 367   // Abbrev for TYPE_CODE_ARRAY.
 368   Abbv = new BitCodeAbbrev();
 369   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 372
 373   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 374
 375   // Emit an entry count so the reader can reserve space.
 376   TypeVals.push_back(TypeList.size());
 377   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 378   TypeVals.clear();
 379
 380   // Loop over all of the types, emitting each in turn.
 381   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 382     Type *T = TypeList[i];
 383     int AbbrevToUse = 0;
 384     unsigned Code = 0;
 385
 386     switch (T->getTypeID()) {
 387     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 388     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 389     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 390     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 391     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 392     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 393     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 394     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 395     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 396     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 397     case Type::IntegerTyID:
 398       // INTEGER: [width]
 399       Code = bitc::TYPE_CODE_INTEGER;
 400       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 401       break;
 402     case Type::PointerTyID: {
 403       PointerType *PTy = cast<PointerType>(T);
 404       // POINTER: [pointee type, address space]
 405       Code = bitc::TYPE_CODE_POINTER;
 406       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 407       unsigned AddressSpace = PTy->getAddressSpace();
 408       TypeVals.push_back(AddressSpace);
 409       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 410       break;
 411     }
 412     case Type::FunctionTyID: {
 413       FunctionType *FT = cast<FunctionType>(T);
 414       // FUNCTION: [isvararg, retty, paramty x N]
 415       Code = bitc::TYPE_CODE_FUNCTION;
 416       TypeVals.push_back(FT->isVarArg());
 417       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 418       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 419         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 420       AbbrevToUse = FunctionAbbrev;
 421       break;
 422     }
 423     case Type::StructTyID: {
 424       StructType *ST = cast<StructType>(T);
 425       // STRUCT: [ispacked, eltty x N]
 426       TypeVals.push_back(ST->isPacked());
 427       // Output all of the element types.
 428       for (StructType::element_iterator I = ST->element_begin(),
 429            E = ST->element_end(); I != E; ++I)
 430         TypeVals.push_back(VE.getTypeID(*I));
 431
 432       if (ST->isLiteral()) {
 433         Code = bitc::TYPE_CODE_STRUCT_ANON;
 434         AbbrevToUse = StructAnonAbbrev;
 435       } else {
 436         if (ST->isOpaque()) {
 437           Code = bitc::TYPE_CODE_OPAQUE;
 438         } else {
 439           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 440           AbbrevToUse = StructNamedAbbrev;
 441         }
 442
 443         // Emit the name if it is present.
 444         if (!ST->getName().empty())
 445           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 446                             StructNameAbbrev, Stream);
 447       }
 448       break;
 449     }
 450     case Type::ArrayTyID: {
 451       ArrayType *AT = cast<ArrayType>(T);
 452       // ARRAY: [numelts, eltty]
 453       Code = bitc::TYPE_CODE_ARRAY;
 454       TypeVals.push_back(AT->getNumElements());
 455       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 456       AbbrevToUse = ArrayAbbrev;
 457       break;
 458     }
 459     case Type::VectorTyID: {
 460       VectorType *VT = cast<VectorType>(T);
 461       // VECTOR [numelts, eltty]
 462       Code = bitc::TYPE_CODE_VECTOR;
 463       TypeVals.push_back(VT->getNumElements());
 464       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 465       break;
 466     }
 467     }
 468
 469     // Emit the finished record.
 470     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 471     TypeVals.clear();
 472   }
 473
 474   Stream.ExitBlock();
 475 }
 476
 477 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 478   switch (GV->getLinkage()) {
 479   case GlobalValue::ExternalLinkage:                 return 0;
 480   case GlobalValue::WeakAnyLinkage:                  return 1;
 481   case GlobalValue::AppendingLinkage:                return 2;
 482   case GlobalValue::InternalLinkage:                 return 3;
 483   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 484   case GlobalValue::ExternalWeakLinkage:             return 7;
 485   case GlobalValue::CommonLinkage:                   return 8;
 486   case GlobalValue::PrivateLinkage:                  return 9;
 487   case GlobalValue::WeakODRLinkage:                  return 10;
 488   case GlobalValue::LinkOnceODRLinkage:              return 11;
 489   case GlobalValue::AvailableExternallyLinkage:      return 12;
 490   case GlobalValue::LinkerPrivateLinkage:            return 13;
 491   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 492   }
 493   llvm_unreachable("Invalid linkage");
 494 }
 495
 496 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 497   switch (GV->getVisibility()) {
 498   case GlobalValue::DefaultVisibility:   return 0;
 499   case GlobalValue::HiddenVisibility:    return 1;
 500   case GlobalValue::ProtectedVisibility: return 2;
 501   }
 502   llvm_unreachable("Invalid visibility");
 503 }
 504
 505 static unsigned getEncodedDLLStorageClass(const GlobalValue *GV) {
 506   switch (GV->getDLLStorageClass()) {
 507   case GlobalValue::DefaultStorageClass:   return 0;
 508   case GlobalValue::DLLImportStorageClass: return 1;
 509   case GlobalValue::DLLExportStorageClass: return 2;
 510   }
 511   llvm_unreachable("Invalid DLL storage class");
 512 }
 513
 514 static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
 515   switch (GV->getThreadLocalMode()) {
 516     case GlobalVariable::NotThreadLocal:         return 0;
 517     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 518     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 519     case GlobalVariable::InitialExecTLSModel:    return 3;
 520     case GlobalVariable::LocalExecTLSModel:      return 4;
 521   }
 522   llvm_unreachable("Invalid TLS model");
 523 }
 524
 525 // Emit top-level description of module, including target triple, inline asm,
 526 // descriptors for global variables, and function prototype info.
 527 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 528                             BitstreamWriter &Stream) {
 529   // Emit various pieces of data attached to a module.
 530   if (!M->getTargetTriple().empty())
 531     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 532                       0/*TODO*/, Stream);
 533   const std::string &DL = M->getDataLayoutStr();
 534   if (!DL.empty())
 535     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 536   if (!M->getModuleInlineAsm().empty())
 537     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 538                       0/*TODO*/, Stream);
 539
 540   // Emit information about sections and GC, computing how many there are. Also
 541   // compute the maximum alignment value.
 542   std::map<std::string, unsigned> SectionMap;
 543   std::map<std::string, unsigned> GCMap;
 544   unsigned MaxAlignment = 0;
 545   unsigned MaxGlobalType = 0;
 546   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 547        GV != E; ++GV) {
 548     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 549     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 550     if (GV->hasSection()) {
 551       // Give section names unique ID's.
 552       unsigned &Entry = SectionMap[GV->getSection()];
 553       if (!Entry) {
 554         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 555                           0/*TODO*/, Stream);
 556         Entry = SectionMap.size();
 557       }
 558     }
 559   }
 560   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 561     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 562     if (F->hasSection()) {
 563       // Give section names unique ID's.
 564       unsigned &Entry = SectionMap[F->getSection()];
 565       if (!Entry) {
 566         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 567                           0/*TODO*/, Stream);
 568         Entry = SectionMap.size();
 569       }
 570     }
 571     if (F->hasGC()) {
 572       // Same for GC names.
 573       unsigned &Entry = GCMap[F->getGC()];
 574       if (!Entry) {
 575         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 576                           0/*TODO*/, Stream);
 577         Entry = GCMap.size();
 578       }
 579     }
 580   }
 581
 582   // Emit abbrev for globals, now that we know # sections and max alignment.
 583   unsigned SimpleGVarAbbrev = 0;
 584   if (!M->global_empty()) {
 585     // Add an abbrev for common globals with no visibility or thread localness.
 586     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 587     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 589                               Log2_32_Ceil(MaxGlobalType+1)));
 590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 593     if (MaxAlignment == 0)                                      // Alignment.
 594       Abbv->Add(BitCodeAbbrevOp(0));
 595     else {
 596       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 597       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 598                                Log2_32_Ceil(MaxEncAlignment+1)));
 599     }
 600     if (SectionMap.empty())                                    // Section.
 601       Abbv->Add(BitCodeAbbrevOp(0));
 602     else
 603       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 604                                Log2_32_Ceil(SectionMap.size()+1)));
 605     // Don't bother emitting vis + thread local.
 606     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 607   }
 608
 609   // Emit the global variable information.
 610   SmallVector<unsigned, 64> Vals;
 611   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 612        GV != E; ++GV) {
 613     unsigned AbbrevToUse = 0;
 614
 615     // GLOBALVAR: [type, isconst, initid,
 616     //             linkage, alignment, section, visibility, threadlocal,
 617     //             unnamed_addr, externally_initialized, dllstorageclass]
 618     Vals.push_back(VE.getTypeID(GV->getType()));
 619     Vals.push_back(GV->isConstant());
 620     Vals.push_back(GV->isDeclaration() ? 0 :
 621                    (VE.getValueID(GV->getInitializer()) + 1));
 622     Vals.push_back(getEncodedLinkage(GV));
 623     Vals.push_back(Log2_32(GV->getAlignment())+1);
 624     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 625     if (GV->isThreadLocal() ||
 626         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 627         GV->hasUnnamedAddr() || GV->isExternallyInitialized() ||
 628         GV->getDLLStorageClass() != GlobalValue::DefaultStorageClass) {
 629       Vals.push_back(getEncodedVisibility(GV));
 630       Vals.push_back(getEncodedThreadLocalMode(GV));
 631       Vals.push_back(GV->hasUnnamedAddr());
 632       Vals.push_back(GV->isExternallyInitialized());
 633       Vals.push_back(getEncodedDLLStorageClass(GV));
 634     } else {
 635       AbbrevToUse = SimpleGVarAbbrev;
 636     }
 637
 638     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 639     Vals.clear();
 640   }
 641
 642   // Emit the function proto information.
 643   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 644     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 645     //             section, visibility, gc, unnamed_addr, prefix]
 646     Vals.push_back(VE.getTypeID(F->getType()));
 647     Vals.push_back(F->getCallingConv());
 648     Vals.push_back(F->isDeclaration());
 649     Vals.push_back(getEncodedLinkage(F));
 650     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 651     Vals.push_back(Log2_32(F->getAlignment())+1);
 652     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 653     Vals.push_back(getEncodedVisibility(F));
 654     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 655     Vals.push_back(F->hasUnnamedAddr());
 656     Vals.push_back(F->hasPrefixData() ? (VE.getValueID(F->getPrefixData()) + 1)
 657                                       : 0);
 658     Vals.push_back(getEncodedDLLStorageClass(F));
 659
 660     unsigned AbbrevToUse = 0;
 661     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 662     Vals.clear();
 663   }
 664
 665   // Emit the alias information.
 666   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 667        AI != E; ++AI) {
 668     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 669     Vals.push_back(VE.getTypeID(AI->getType()));
 670     Vals.push_back(VE.getValueID(AI->getAliasee()));
 671     Vals.push_back(getEncodedLinkage(AI));
 672     Vals.push_back(getEncodedVisibility(AI));
 673     Vals.push_back(getEncodedDLLStorageClass(AI));
 674     unsigned AbbrevToUse = 0;
 675     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 676     Vals.clear();
 677   }
 678 }
 679
 680 static uint64_t GetOptimizationFlags(const Value *V) {
 681   uint64_t Flags = 0;
 682
 683   if (const OverflowingBinaryOperator *OBO =
 684         dyn_cast<OverflowingBinaryOperator>(V)) {
 685     if (OBO->hasNoSignedWrap())
 686       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 687     if (OBO->hasNoUnsignedWrap())
 688       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 689   } else if (const PossiblyExactOperator *PEO =
 690                dyn_cast<PossiblyExactOperator>(V)) {
 691     if (PEO->isExact())
 692       Flags |= 1 << bitc::PEO_EXACT;
 693   } else if (const FPMathOperator *FPMO =
 694              dyn_cast<const FPMathOperator>(V)) {
 695     if (FPMO->hasUnsafeAlgebra())
 696       Flags |= FastMathFlags::UnsafeAlgebra;
 697     if (FPMO->hasNoNaNs())
 698       Flags |= FastMathFlags::NoNaNs;
 699     if (FPMO->hasNoInfs())
 700       Flags |= FastMathFlags::NoInfs;
 701     if (FPMO->hasNoSignedZeros())
 702       Flags |= FastMathFlags::NoSignedZeros;
 703     if (FPMO->hasAllowReciprocal())
 704       Flags |= FastMathFlags::AllowReciprocal;
 705   }
 706
 707   return Flags;
 708 }
 709
 710 static void WriteMDNode(const MDNode *N,
 711                         const ValueEnumerator &VE,
 712                         BitstreamWriter &Stream,
 713                         SmallVectorImpl<uint64_t> &Record) {
 714   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 715     if (N->getOperand(i)) {
 716       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 717       Record.push_back(VE.getValueID(N->getOperand(i)));
 718     } else {
 719       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 720       Record.push_back(0);
 721     }
 722   }
 723   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 724                                            bitc::METADATA_NODE;
 725   Stream.EmitRecord(MDCode, Record, 0);
 726   Record.clear();
 727 }
 728
 729 static void WriteModuleMetadata(const Module *M,
 730                                 const ValueEnumerator &VE,
 731                                 BitstreamWriter &Stream) {
 732   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 733   bool StartedMetadataBlock = false;
 734   unsigned MDSAbbrev = 0;
 735   SmallVector<uint64_t, 64> Record;
 736   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 737
 738     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 739       if (!N->isFunctionLocal() || !N->getFunction()) {
 740         if (!StartedMetadataBlock) {
 741           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 742           StartedMetadataBlock = true;
 743         }
 744         WriteMDNode(N, VE, Stream, Record);
 745       }
 746     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 747       if (!StartedMetadataBlock)  {
 748         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 749
 750         // Abbrev for METADATA_STRING.
 751         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 752         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 753         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 754         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 755         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 756         StartedMetadataBlock = true;
 757       }
 758
 759       // Code: [strchar x N]
 760       Record.append(MDS->begin(), MDS->end());
 761
 762       // Emit the finished record.
 763       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 764       Record.clear();
 765     }
 766   }
 767
 768   // Write named metadata.
 769   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 770        E = M->named_metadata_end(); I != E; ++I) {
 771     const NamedMDNode *NMD = I;
 772     if (!StartedMetadataBlock)  {
 773       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 774       StartedMetadataBlock = true;
 775     }
 776
 777     // Write name.
 778     StringRef Str = NMD->getName();
 779     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 780       Record.push_back(Str[i]);
 781     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 782     Record.clear();
 783
 784     // Write named metadata operands.
 785     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 786       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 787     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 788     Record.clear();
 789   }
 790
 791   if (StartedMetadataBlock)
 792     Stream.ExitBlock();
 793 }
 794
 795 static void WriteFunctionLocalMetadata(const Function &F,
 796                                        const ValueEnumerator &VE,
 797                                        BitstreamWriter &Stream) {
 798   bool StartedMetadataBlock = false;
 799   SmallVector<uint64_t, 64> Record;
 800   const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
 801   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 802     if (const MDNode *N = Vals[i])
 803       if (N->isFunctionLocal() && N->getFunction() == &F) {
 804         if (!StartedMetadataBlock) {
 805           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 806           StartedMetadataBlock = true;
 807         }
 808         WriteMDNode(N, VE, Stream, Record);
 809       }
 810
 811   if (StartedMetadataBlock)
 812     Stream.ExitBlock();
 813 }
 814
 815 static void WriteMetadataAttachment(const Function &F,
 816                                     const ValueEnumerator &VE,
 817                                     BitstreamWriter &Stream) {
 818   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 819
 820   SmallVector<uint64_t, 64> Record;
 821
 822   // Write metadata attachments
 823   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 824   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 825
 826   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 827     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 828          I != E; ++I) {
 829       MDs.clear();
 830       I->getAllMetadataOtherThanDebugLoc(MDs);
 831
 832       // If no metadata, ignore instruction.
 833       if (MDs.empty()) continue;
 834
 835       Record.push_back(VE.getInstructionID(I));
 836
 837       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 838         Record.push_back(MDs[i].first);
 839         Record.push_back(VE.getValueID(MDs[i].second));
 840       }
 841       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 842       Record.clear();
 843     }
 844
 845   Stream.ExitBlock();
 846 }
 847
 848 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 849   SmallVector<uint64_t, 64> Record;
 850
 851   // Write metadata kinds
 852   // METADATA_KIND - [n x [id, name]]
 853   SmallVector<StringRef, 8> Names;
 854   M->getMDKindNames(Names);
 855
 856   if (Names.empty()) return;
 857
 858   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 859
 860   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 861     Record.push_back(MDKindID);
 862     StringRef KName = Names[MDKindID];
 863     Record.append(KName.begin(), KName.end());
 864
 865     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 866     Record.clear();
 867   }
 868
 869   Stream.ExitBlock();
 870 }
 871
 872 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 873   if ((int64_t)V >= 0)
 874     Vals.push_back(V << 1);
 875   else
 876     Vals.push_back((-V << 1) | 1);
 877 }
 878
 879 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 880                            const ValueEnumerator &VE,
 881                            BitstreamWriter &Stream, bool isGlobal) {
 882   if (FirstVal == LastVal) return;
 883
 884   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 885
 886   unsigned AggregateAbbrev = 0;
 887   unsigned String8Abbrev = 0;
 888   unsigned CString7Abbrev = 0;
 889   unsigned CString6Abbrev = 0;
 890   // If this is a constant pool for the module, emit module-specific abbrevs.
 891   if (isGlobal) {
 892     // Abbrev for CST_CODE_AGGREGATE.
 893     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 894     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 895     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 897     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 898
 899     // Abbrev for CST_CODE_STRING.
 900     Abbv = new BitCodeAbbrev();
 901     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 902     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 903     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 904     String8Abbrev = Stream.EmitAbbrev(Abbv);
 905     // Abbrev for CST_CODE_CSTRING.
 906     Abbv = new BitCodeAbbrev();
 907     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 908     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 909     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 910     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 911     // Abbrev for CST_CODE_CSTRING.
 912     Abbv = new BitCodeAbbrev();
 913     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 914     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 915     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 916     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 917   }
 918
 919   SmallVector<uint64_t, 64> Record;
 920
 921   const ValueEnumerator::ValueList &Vals = VE.getValues();
 922   Type *LastTy = 0;
 923   for (unsigned i = FirstVal; i != LastVal; ++i) {
 924     const Value *V = Vals[i].first;
 925     // If we need to switch types, do so now.
 926     if (V->getType() != LastTy) {
 927       LastTy = V->getType();
 928       Record.push_back(VE.getTypeID(LastTy));
 929       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 930                         CONSTANTS_SETTYPE_ABBREV);
 931       Record.clear();
 932     }
 933
 934     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 935       Record.push_back(unsigned(IA->hasSideEffects()) |
 936                        unsigned(IA->isAlignStack()) << 1 |
 937                        unsigned(IA->getDialect()&1) << 2);
 938
 939       // Add the asm string.
 940       const std::string &AsmStr = IA->getAsmString();
 941       Record.push_back(AsmStr.size());
 942       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 943         Record.push_back(AsmStr[i]);
 944
 945       // Add the constraint string.
 946       const std::string &ConstraintStr = IA->getConstraintString();
 947       Record.push_back(ConstraintStr.size());
 948       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 949         Record.push_back(ConstraintStr[i]);
 950       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 951       Record.clear();
 952       continue;
 953     }
 954     const Constant *C = cast<Constant>(V);
 955     unsigned Code = -1U;
 956     unsigned AbbrevToUse = 0;
 957     if (C->isNullValue()) {
 958       Code = bitc::CST_CODE_NULL;
 959     } else if (isa<UndefValue>(C)) {
 960       Code = bitc::CST_CODE_UNDEF;
 961     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 962       if (IV->getBitWidth() <= 64) {
 963         uint64_t V = IV->getSExtValue();
 964         emitSignedInt64(Record, V);
 965         Code = bitc::CST_CODE_INTEGER;
 966         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 967       } else {                             // Wide integers, > 64 bits in size.
 968         // We have an arbitrary precision integer value to write whose
 969         // bit width is > 64. However, in canonical unsigned integer
 970         // format it is likely that the high bits are going to be zero.
 971         // So, we only write the number of active words.
 972         unsigned NWords = IV->getValue().getActiveWords();
 973         const uint64_t *RawWords = IV->getValue().getRawData();
 974         for (unsigned i = 0; i != NWords; ++i) {
 975           emitSignedInt64(Record, RawWords[i]);
 976         }
 977         Code = bitc::CST_CODE_WIDE_INTEGER;
 978       }
 979     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 980       Code = bitc::CST_CODE_FLOAT;
 981       Type *Ty = CFP->getType();
 982       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
 983         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 984       } else if (Ty->isX86_FP80Ty()) {
 985         // api needed to prevent premature destruction
 986         // bits are not in the same order as a normal i80 APInt, compensate.
 987         APInt api = CFP->getValueAPF().bitcastToAPInt();
 988         const uint64_t *p = api.getRawData();
 989         Record.push_back((p[1] << 48) | (p[0] >> 16));
 990         Record.push_back(p[0] & 0xffffLL);
 991       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 992         APInt api = CFP->getValueAPF().bitcastToAPInt();
 993         const uint64_t *p = api.getRawData();
 994         Record.push_back(p[0]);
 995         Record.push_back(p[1]);
 996       } else {
 997         assert (0 && "Unknown FP type!");
 998       }
 999     } else if (isa<ConstantDataSequential>(C) &&
1000                cast<ConstantDataSequential>(C)->isString()) {
1001       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1002       // Emit constant strings specially.
1003       unsigned NumElts = Str->getNumElements();
1004       // If this is a null-terminated string, use the denser CSTRING encoding.
1005       if (Str->isCString()) {
1006         Code = bitc::CST_CODE_CSTRING;
1007         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1008       } else {
1009         Code = bitc::CST_CODE_STRING;
1010         AbbrevToUse = String8Abbrev;
1011       }
1012       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1013       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1014       for (unsigned i = 0; i != NumElts; ++i) {
1015         unsigned char V = Str->getElementAsInteger(i);
1016         Record.push_back(V);
1017         isCStr7 &= (V & 128) == 0;
1018         if (isCStrChar6)
1019           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1020       }
1021
1022       if (isCStrChar6)
1023         AbbrevToUse = CString6Abbrev;
1024       else if (isCStr7)
1025         AbbrevToUse = CString7Abbrev;
1026     } else if (const ConstantDataSequential *CDS =
1027                   dyn_cast<ConstantDataSequential>(C)) {
1028       Code = bitc::CST_CODE_DATA;
1029       Type *EltTy = CDS->getType()->getElementType();
1030       if (isa<IntegerType>(EltTy)) {
1031         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1032           Record.push_back(CDS->getElementAsInteger(i));
1033       } else if (EltTy->isFloatTy()) {
1034         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1035           union { float F; uint32_t I; };
1036           F = CDS->getElementAsFloat(i);
1037           Record.push_back(I);
1038         }
1039       } else {
1040         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1041         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1042           union { double F; uint64_t I; };
1043           F = CDS->getElementAsDouble(i);
1044           Record.push_back(I);
1045         }
1046       }
1047     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1048                isa<ConstantVector>(C)) {
1049       Code = bitc::CST_CODE_AGGREGATE;
1050       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1051         Record.push_back(VE.getValueID(C->getOperand(i)));
1052       AbbrevToUse = AggregateAbbrev;
1053     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1054       switch (CE->getOpcode()) {
1055       default:
1056         if (Instruction::isCast(CE->getOpcode())) {
1057           Code = bitc::CST_CODE_CE_CAST;
1058           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1059           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1060           Record.push_back(VE.getValueID(C->getOperand(0)));
1061           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1062         } else {
1063           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1064           Code = bitc::CST_CODE_CE_BINOP;
1065           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1066           Record.push_back(VE.getValueID(C->getOperand(0)));
1067           Record.push_back(VE.getValueID(C->getOperand(1)));
1068           uint64_t Flags = GetOptimizationFlags(CE);
1069           if (Flags != 0)
1070             Record.push_back(Flags);
1071         }
1072         break;
1073       case Instruction::GetElementPtr:
1074         Code = bitc::CST_CODE_CE_GEP;
1075         if (cast<GEPOperator>(C)->isInBounds())
1076           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1077         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1078           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1079           Record.push_back(VE.getValueID(C->getOperand(i)));
1080         }
1081         break;
1082       case Instruction::Select:
1083         Code = bitc::CST_CODE_CE_SELECT;
1084         Record.push_back(VE.getValueID(C->getOperand(0)));
1085         Record.push_back(VE.getValueID(C->getOperand(1)));
1086         Record.push_back(VE.getValueID(C->getOperand(2)));
1087         break;
1088       case Instruction::ExtractElement:
1089         Code = bitc::CST_CODE_CE_EXTRACTELT;
1090         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1091         Record.push_back(VE.getValueID(C->getOperand(0)));
1092         Record.push_back(VE.getValueID(C->getOperand(1)));
1093         break;
1094       case Instruction::InsertElement:
1095         Code = bitc::CST_CODE_CE_INSERTELT;
1096         Record.push_back(VE.getValueID(C->getOperand(0)));
1097         Record.push_back(VE.getValueID(C->getOperand(1)));
1098         Record.push_back(VE.getValueID(C->getOperand(2)));
1099         break;
1100       case Instruction::ShuffleVector:
1101         // If the return type and argument types are the same, this is a
1102         // standard shufflevector instruction.  If the types are different,
1103         // then the shuffle is widening or truncating the input vectors, and
1104         // the argument type must also be encoded.
1105         if (C->getType() == C->getOperand(0)->getType()) {
1106           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1107         } else {
1108           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1109           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1110         }
1111         Record.push_back(VE.getValueID(C->getOperand(0)));
1112         Record.push_back(VE.getValueID(C->getOperand(1)));
1113         Record.push_back(VE.getValueID(C->getOperand(2)));
1114         break;
1115       case Instruction::ICmp:
1116       case Instruction::FCmp:
1117         Code = bitc::CST_CODE_CE_CMP;
1118         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1119         Record.push_back(VE.getValueID(C->getOperand(0)));
1120         Record.push_back(VE.getValueID(C->getOperand(1)));
1121         Record.push_back(CE->getPredicate());
1122         break;
1123       }
1124     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1125       Code = bitc::CST_CODE_BLOCKADDRESS;
1126       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1127       Record.push_back(VE.getValueID(BA->getFunction()));
1128       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1129     } else {
1130 #ifndef NDEBUG
1131       C->dump();
1132 #endif
1133       llvm_unreachable("Unknown constant!");
1134     }
1135     Stream.EmitRecord(Code, Record, AbbrevToUse);
1136     Record.clear();
1137   }
1138
1139   Stream.ExitBlock();
1140 }
1141
1142 static void WriteModuleConstants(const ValueEnumerator &VE,
1143                                  BitstreamWriter &Stream) {
1144   const ValueEnumerator::ValueList &Vals = VE.getValues();
1145
1146   // Find the first constant to emit, which is the first non-globalvalue value.
1147   // We know globalvalues have been emitted by WriteModuleInfo.
1148   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1149     if (!isa<GlobalValue>(Vals[i].first)) {
1150       WriteConstants(i, Vals.size(), VE, Stream, true);
1151       return;
1152     }
1153   }
1154 }
1155
1156 /// PushValueAndType - The file has to encode both the value and type id for
1157 /// many values, because we need to know what type to create for forward
1158 /// references.  However, most operands are not forward references, so this type
1159 /// field is not needed.
1160 ///
1161 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1162 /// instruction ID, then it is a forward reference, and it also includes the
1163 /// type ID.  The value ID that is written is encoded relative to the InstID.
1164 static bool PushValueAndType(const Value *V, unsigned InstID,
1165                              SmallVectorImpl<unsigned> &Vals,
1166                              ValueEnumerator &VE) {
1167   unsigned ValID = VE.getValueID(V);
1168   // Make encoding relative to the InstID.
1169   Vals.push_back(InstID - ValID);
1170   if (ValID >= InstID) {
1171     Vals.push_back(VE.getTypeID(V->getType()));
1172     return true;
1173   }
1174   return false;
1175 }
1176
1177 /// pushValue - Like PushValueAndType, but where the type of the value is
1178 /// omitted (perhaps it was already encoded in an earlier operand).
1179 static void pushValue(const Value *V, unsigned InstID,
1180                       SmallVectorImpl<unsigned> &Vals,
1181                       ValueEnumerator &VE) {
1182   unsigned ValID = VE.getValueID(V);
1183   Vals.push_back(InstID - ValID);
1184 }
1185
1186 static void pushValueSigned(const Value *V, unsigned InstID,
1187                             SmallVectorImpl<uint64_t> &Vals,
1188                             ValueEnumerator &VE) {
1189   unsigned ValID = VE.getValueID(V);
1190   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1191   emitSignedInt64(Vals, diff);
1192 }
1193
1194 /// WriteInstruction - Emit an instruction to the specified stream.
1195 static void WriteInstruction(const Instruction &I, unsigned InstID,
1196                              ValueEnumerator &VE, BitstreamWriter &Stream,
1197                              SmallVectorImpl<unsigned> &Vals) {
1198   unsigned Code = 0;
1199   unsigned AbbrevToUse = 0;
1200   VE.setInstructionID(&I);
1201   switch (I.getOpcode()) {
1202   default:
1203     if (Instruction::isCast(I.getOpcode())) {
1204       Code = bitc::FUNC_CODE_INST_CAST;
1205       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1206         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1207       Vals.push_back(VE.getTypeID(I.getType()));
1208       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1209     } else {
1210       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1211       Code = bitc::FUNC_CODE_INST_BINOP;
1212       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1213         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1214       pushValue(I.getOperand(1), InstID, Vals, VE);
1215       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1216       uint64_t Flags = GetOptimizationFlags(&I);
1217       if (Flags != 0) {
1218         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1219           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1220         Vals.push_back(Flags);
1221       }
1222     }
1223     break;
1224
1225   case Instruction::GetElementPtr:
1226     Code = bitc::FUNC_CODE_INST_GEP;
1227     if (cast<GEPOperator>(&I)->isInBounds())
1228       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1229     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1230       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1231     break;
1232   case Instruction::ExtractValue: {
1233     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1234     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1235     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1236     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1237       Vals.push_back(*i);
1238     break;
1239   }
1240   case Instruction::InsertValue: {
1241     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1242     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1243     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1244     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1245     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1246       Vals.push_back(*i);
1247     break;
1248   }
1249   case Instruction::Select:
1250     Code = bitc::FUNC_CODE_INST_VSELECT;
1251     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1252     pushValue(I.getOperand(2), InstID, Vals, VE);
1253     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1254     break;
1255   case Instruction::ExtractElement:
1256     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1257     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1258     pushValue(I.getOperand(1), InstID, Vals, VE);
1259     break;
1260   case Instruction::InsertElement:
1261     Code = bitc::FUNC_CODE_INST_INSERTELT;
1262     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1263     pushValue(I.getOperand(1), InstID, Vals, VE);
1264     pushValue(I.getOperand(2), InstID, Vals, VE);
1265     break;
1266   case Instruction::ShuffleVector:
1267     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1268     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1269     pushValue(I.getOperand(1), InstID, Vals, VE);
1270     pushValue(I.getOperand(2), InstID, Vals, VE);
1271     break;
1272   case Instruction::ICmp:
1273   case Instruction::FCmp:
1274     // compare returning Int1Ty or vector of Int1Ty
1275     Code = bitc::FUNC_CODE_INST_CMP2;
1276     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1277     pushValue(I.getOperand(1), InstID, Vals, VE);
1278     Vals.push_back(cast<CmpInst>(I).getPredicate());
1279     break;
1280
1281   case Instruction::Ret:
1282     {
1283       Code = bitc::FUNC_CODE_INST_RET;
1284       unsigned NumOperands = I.getNumOperands();
1285       if (NumOperands == 0)
1286         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1287       else if (NumOperands == 1) {
1288         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1289           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1290       } else {
1291         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1292           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1293       }
1294     }
1295     break;
1296   case Instruction::Br:
1297     {
1298       Code = bitc::FUNC_CODE_INST_BR;
1299       const BranchInst &II = cast<BranchInst>(I);
1300       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1301       if (II.isConditional()) {
1302         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1303         pushValue(II.getCondition(), InstID, Vals, VE);
1304       }
1305     }
1306     break;
1307   case Instruction::Switch:
1308     {
1309       Code = bitc::FUNC_CODE_INST_SWITCH;
1310       const SwitchInst &SI = cast<SwitchInst>(I);
1311       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1312       pushValue(SI.getCondition(), InstID, Vals, VE);
1313       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1314       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1315            i != e; ++i) {
1316         Vals.push_back(VE.getValueID(i.getCaseValue()));
1317         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1318       }
1319     }
1320     break;
1321   case Instruction::IndirectBr:
1322     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1323     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1324     // Encode the address operand as relative, but not the basic blocks.
1325     pushValue(I.getOperand(0), InstID, Vals, VE);
1326     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1327       Vals.push_back(VE.getValueID(I.getOperand(i)));
1328     break;
1329
1330   case Instruction::Invoke: {
1331     const InvokeInst *II = cast<InvokeInst>(&I);
1332     const Value *Callee(II->getCalledValue());
1333     PointerType *PTy = cast<PointerType>(Callee->getType());
1334     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1335     Code = bitc::FUNC_CODE_INST_INVOKE;
1336
1337     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1338     Vals.push_back(II->getCallingConv());
1339     Vals.push_back(VE.getValueID(II->getNormalDest()));
1340     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1341     PushValueAndType(Callee, InstID, Vals, VE);
1342
1343     // Emit value #'s for the fixed parameters.
1344     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1345       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1346
1347     // Emit type/value pairs for varargs params.
1348     if (FTy->isVarArg()) {
1349       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1350            i != e; ++i)
1351         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1352     }
1353     break;
1354   }
1355   case Instruction::Resume:
1356     Code = bitc::FUNC_CODE_INST_RESUME;
1357     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1358     break;
1359   case Instruction::Unreachable:
1360     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1361     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1362     break;
1363
1364   case Instruction::PHI: {
1365     const PHINode &PN = cast<PHINode>(I);
1366     Code = bitc::FUNC_CODE_INST_PHI;
1367     // With the newer instruction encoding, forward references could give
1368     // negative valued IDs.  This is most common for PHIs, so we use
1369     // signed VBRs.
1370     SmallVector<uint64_t, 128> Vals64;
1371     Vals64.push_back(VE.getTypeID(PN.getType()));
1372     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1373       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1374       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1375     }
1376     // Emit a Vals64 vector and exit.
1377     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1378     Vals64.clear();
1379     return;
1380   }
1381
1382   case Instruction::LandingPad: {
1383     const LandingPadInst &LP = cast<LandingPadInst>(I);
1384     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1385     Vals.push_back(VE.getTypeID(LP.getType()));
1386     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1387     Vals.push_back(LP.isCleanup());
1388     Vals.push_back(LP.getNumClauses());
1389     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1390       if (LP.isCatch(I))
1391         Vals.push_back(LandingPadInst::Catch);
1392       else
1393         Vals.push_back(LandingPadInst::Filter);
1394       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1395     }
1396     break;
1397   }
1398
1399   case Instruction::Alloca:
1400     Code = bitc::FUNC_CODE_INST_ALLOCA;
1401     Vals.push_back(VE.getTypeID(I.getType()));
1402     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1403     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1404     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1405     break;
1406
1407   case Instruction::Load:
1408     if (cast<LoadInst>(I).isAtomic()) {
1409       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1410       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1411     } else {
1412       Code = bitc::FUNC_CODE_INST_LOAD;
1413       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1414         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1415     }
1416     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1417     Vals.push_back(cast<LoadInst>(I).isVolatile());
1418     if (cast<LoadInst>(I).isAtomic()) {
1419       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1420       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1421     }
1422     break;
1423   case Instruction::Store:
1424     if (cast<StoreInst>(I).isAtomic())
1425       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1426     else
1427       Code = bitc::FUNC_CODE_INST_STORE;
1428     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1429     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1430     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1431     Vals.push_back(cast<StoreInst>(I).isVolatile());
1432     if (cast<StoreInst>(I).isAtomic()) {
1433       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1434       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1435     }
1436     break;
1437   case Instruction::AtomicCmpXchg:
1438     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1439     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1440     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1441     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1442     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1443     Vals.push_back(GetEncodedOrdering(
1444                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1445     Vals.push_back(GetEncodedSynchScope(
1446                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1447     Vals.push_back(GetEncodedOrdering(
1448                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1449     break;
1450   case Instruction::AtomicRMW:
1451     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1452     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1453     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1454     Vals.push_back(GetEncodedRMWOperation(
1455                      cast<AtomicRMWInst>(I).getOperation()));
1456     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1457     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1458     Vals.push_back(GetEncodedSynchScope(
1459                      cast<AtomicRMWInst>(I).getSynchScope()));
1460     break;
1461   case Instruction::Fence:
1462     Code = bitc::FUNC_CODE_INST_FENCE;
1463     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1464     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1465     break;
1466   case Instruction::Call: {
1467     const CallInst &CI = cast<CallInst>(I);
1468     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1469     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1470
1471     Code = bitc::FUNC_CODE_INST_CALL;
1472
1473     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1474     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1475     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1476
1477     // Emit value #'s for the fixed parameters.
1478     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1479       // Check for labels (can happen with asm labels).
1480       if (FTy->getParamType(i)->isLabelTy())
1481         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1482       else
1483         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1484     }
1485
1486     // Emit type/value pairs for varargs params.
1487     if (FTy->isVarArg()) {
1488       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1489            i != e; ++i)
1490         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1491     }
1492     break;
1493   }
1494   case Instruction::VAArg:
1495     Code = bitc::FUNC_CODE_INST_VAARG;
1496     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1497     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1498     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1499     break;
1500   }
1501
1502   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1503   Vals.clear();
1504 }
1505
1506 // Emit names for globals/functions etc.
1507 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1508                                   const ValueEnumerator &VE,
1509                                   BitstreamWriter &Stream) {
1510   if (VST.empty()) return;
1511   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1512
1513   // FIXME: Set up the abbrev, we know how many values there are!
1514   // FIXME: We know if the type names can use 7-bit ascii.
1515   SmallVector<unsigned, 64> NameVals;
1516
1517   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1518        SI != SE; ++SI) {
1519
1520     const ValueName &Name = *SI;
1521
1522     // Figure out the encoding to use for the name.
1523     bool is7Bit = true;
1524     bool isChar6 = true;
1525     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1526          C != E; ++C) {
1527       if (isChar6)
1528         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1529       if ((unsigned char)*C & 128) {
1530         is7Bit = false;
1531         break;  // don't bother scanning the rest.
1532       }
1533     }
1534
1535     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1536
1537     // VST_ENTRY:   [valueid, namechar x N]
1538     // VST_BBENTRY: [bbid, namechar x N]
1539     unsigned Code;
1540     if (isa<BasicBlock>(SI->getValue())) {
1541       Code = bitc::VST_CODE_BBENTRY;
1542       if (isChar6)
1543         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1544     } else {
1545       Code = bitc::VST_CODE_ENTRY;
1546       if (isChar6)
1547         AbbrevToUse = VST_ENTRY_6_ABBREV;
1548       else if (is7Bit)
1549         AbbrevToUse = VST_ENTRY_7_ABBREV;
1550     }
1551
1552     NameVals.push_back(VE.getValueID(SI->getValue()));
1553     for (const char *P = Name.getKeyData(),
1554          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1555       NameVals.push_back((unsigned char)*P);
1556
1557     // Emit the finished record.
1558     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1559     NameVals.clear();
1560   }
1561   Stream.ExitBlock();
1562 }
1563
1564 /// WriteFunction - Emit a function body to the module stream.
1565 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1566                           BitstreamWriter &Stream) {
1567   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1568   VE.incorporateFunction(F);
1569
1570   SmallVector<unsigned, 64> Vals;
1571
1572   // Emit the number of basic blocks, so the reader can create them ahead of
1573   // time.
1574   Vals.push_back(VE.getBasicBlocks().size());
1575   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1576   Vals.clear();
1577
1578   // If there are function-local constants, emit them now.
1579   unsigned CstStart, CstEnd;
1580   VE.getFunctionConstantRange(CstStart, CstEnd);
1581   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1582
1583   // If there is function-local metadata, emit it now.
1584   WriteFunctionLocalMetadata(F, VE, Stream);
1585
1586   // Keep a running idea of what the instruction ID is.
1587   unsigned InstID = CstEnd;
1588
1589   bool NeedsMetadataAttachment = false;
1590
1591   DebugLoc LastDL;
1592
1593   // Finally, emit all the instructions, in order.
1594   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1595     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1596          I != E; ++I) {
1597       WriteInstruction(*I, InstID, VE, Stream, Vals);
1598
1599       if (!I->getType()->isVoidTy())
1600         ++InstID;
1601
1602       // If the instruction has metadata, write a metadata attachment later.
1603       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1604
1605       // If the instruction has a debug location, emit it.
1606       DebugLoc DL = I->getDebugLoc();
1607       if (DL.isUnknown()) {
1608         // nothing todo.
1609       } else if (DL == LastDL) {
1610         // Just repeat the same debug loc as last time.
1611         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1612       } else {
1613         MDNode *Scope, *IA;
1614         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1615
1616         Vals.push_back(DL.getLine());
1617         Vals.push_back(DL.getCol());
1618         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1619         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1620         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1621         Vals.clear();
1622
1623         LastDL = DL;
1624       }
1625     }
1626
1627   // Emit names for all the instructions etc.
1628   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1629
1630   if (NeedsMetadataAttachment)
1631     WriteMetadataAttachment(F, VE, Stream);
1632   VE.purgeFunction();
1633   Stream.ExitBlock();
1634 }
1635
1636 // Emit blockinfo, which defines the standard abbreviations etc.
1637 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1638   // We only want to emit block info records for blocks that have multiple
1639   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1640   // Other blocks can define their abbrevs inline.
1641   Stream.EnterBlockInfoBlock(2);
1642
1643   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1644     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1645     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1647     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1649     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1650                                    Abbv) != VST_ENTRY_8_ABBREV)
1651       llvm_unreachable("Unexpected abbrev ordering!");
1652   }
1653
1654   { // 7-bit fixed width VST_ENTRY strings.
1655     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1656     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1658     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1659     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1660     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1661                                    Abbv) != VST_ENTRY_7_ABBREV)
1662       llvm_unreachable("Unexpected abbrev ordering!");
1663   }
1664   { // 6-bit char6 VST_ENTRY strings.
1665     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1666     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1670     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1671                                    Abbv) != VST_ENTRY_6_ABBREV)
1672       llvm_unreachable("Unexpected abbrev ordering!");
1673   }
1674   { // 6-bit char6 VST_BBENTRY strings.
1675     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1676     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1680     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1681                                    Abbv) != VST_BBENTRY_6_ABBREV)
1682       llvm_unreachable("Unexpected abbrev ordering!");
1683   }
1684
1685
1686
1687   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1688     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1689     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1690     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1691                               Log2_32_Ceil(VE.getTypes().size()+1)));
1692     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1693                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1694       llvm_unreachable("Unexpected abbrev ordering!");
1695   }
1696
1697   { // INTEGER abbrev for CONSTANTS_BLOCK.
1698     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1699     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1700     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1701     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1702                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1703       llvm_unreachable("Unexpected abbrev ordering!");
1704   }
1705
1706   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1707     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1708     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1709     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1710     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1711                               Log2_32_Ceil(VE.getTypes().size()+1)));
1712     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1713
1714     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1715                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1716       llvm_unreachable("Unexpected abbrev ordering!");
1717   }
1718   { // NULL abbrev for CONSTANTS_BLOCK.
1719     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1720     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1721     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1722                                    Abbv) != CONSTANTS_NULL_Abbrev)
1723       llvm_unreachable("Unexpected abbrev ordering!");
1724   }
1725
1726   // FIXME: This should only use space for first class types!
1727
1728   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1729     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1730     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1731     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1732     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1734     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1735                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1736       llvm_unreachable("Unexpected abbrev ordering!");
1737   }
1738   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1739     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1740     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1741     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1742     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1743     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1744     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1745                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1746       llvm_unreachable("Unexpected abbrev ordering!");
1747   }
1748   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1749     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1750     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1751     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1752     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1753     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1754     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1755     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1756                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1757       llvm_unreachable("Unexpected abbrev ordering!");
1758   }
1759   { // INST_CAST abbrev for FUNCTION_BLOCK.
1760     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1761     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1762     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1763     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1764                               Log2_32_Ceil(VE.getTypes().size()+1)));
1765     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1766     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1767                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1768       llvm_unreachable("Unexpected abbrev ordering!");
1769   }
1770
1771   { // INST_RET abbrev for FUNCTION_BLOCK.
1772     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1773     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1774     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1775                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1776       llvm_unreachable("Unexpected abbrev ordering!");
1777   }
1778   { // INST_RET abbrev for FUNCTION_BLOCK.
1779     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1780     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1781     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1782     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1783                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1784       llvm_unreachable("Unexpected abbrev ordering!");
1785   }
1786   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1787     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1788     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1789     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1790                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1791       llvm_unreachable("Unexpected abbrev ordering!");
1792   }
1793
1794   Stream.ExitBlock();
1795 }
1796
1797 // Sort the Users based on the order in which the reader parses the bitcode
1798 // file.
1799 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1800   // TODO: Implement.
1801   return true;
1802 }
1803
1804 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1805                          BitstreamWriter &Stream) {
1806
1807   // One or zero uses can't get out of order.
1808   if (V->use_empty() || V->hasNUses(1))
1809     return;
1810
1811   // Make a copy of the in-memory use-list for sorting.
1812   SmallVector<const User*, 8> UserList(V->user_begin(), V->user_end());
1813
1814   // Sort the copy based on the order read by the BitcodeReader.
1815   std::sort(UserList.begin(), UserList.end(), bitcodereader_order);
1816
1817   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1818   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1819
1820   // TODO: Emit the USELIST_CODE_ENTRYs.
1821 }
1822
1823 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1824                                  BitstreamWriter &Stream) {
1825   VE.incorporateFunction(*F);
1826
1827   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1828        AI != AE; ++AI)
1829     WriteUseList(AI, VE, Stream);
1830   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1831        ++BB) {
1832     WriteUseList(BB, VE, Stream);
1833     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1834          ++II) {
1835       WriteUseList(II, VE, Stream);
1836       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1837            OI != E; ++OI) {
1838         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1839             isa<InlineAsm>(*OI))
1840           WriteUseList(*OI, VE, Stream);
1841       }
1842     }
1843   }
1844   VE.purgeFunction();
1845 }
1846
1847 // Emit use-lists.
1848 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1849                                 BitstreamWriter &Stream) {
1850   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1851
1852   // XXX: this modifies the module, but in a way that should never change the
1853   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1854   // contain entries in the use_list that do not exist in the Module and are
1855   // not stored in the .bc file.
1856   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1857        I != E; ++I)
1858     I->removeDeadConstantUsers();
1859
1860   // Write the global variables.
1861   for (Module::const_global_iterator GI = M->global_begin(),
1862          GE = M->global_end(); GI != GE; ++GI) {
1863     WriteUseList(GI, VE, Stream);
1864
1865     // Write the global variable initializers.
1866     if (GI->hasInitializer())
1867       WriteUseList(GI->getInitializer(), VE, Stream);
1868   }
1869
1870   // Write the functions.
1871   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1872     WriteUseList(FI, VE, Stream);
1873     if (!FI->isDeclaration())
1874       WriteFunctionUseList(FI, VE, Stream);
1875     if (FI->hasPrefixData())
1876       WriteUseList(FI->getPrefixData(), VE, Stream);
1877   }
1878
1879   // Write the aliases.
1880   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1881        AI != AE; ++AI) {
1882     WriteUseList(AI, VE, Stream);
1883     WriteUseList(AI->getAliasee(), VE, Stream);
1884   }
1885
1886   Stream.ExitBlock();
1887 }
1888
1889 /// WriteModule - Emit the specified module to the bitstream.
1890 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1891   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1892
1893   SmallVector<unsigned, 1> Vals;
1894   unsigned CurVersion = 1;
1895   Vals.push_back(CurVersion);
1896   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1897
1898   // Analyze the module, enumerating globals, functions, etc.
1899   ValueEnumerator VE(M);
1900
1901   // Emit blockinfo, which defines the standard abbreviations etc.
1902   WriteBlockInfo(VE, Stream);
1903
1904   // Emit information about attribute groups.
1905   WriteAttributeGroupTable(VE, Stream);
1906
1907   // Emit information about parameter attributes.
1908   WriteAttributeTable(VE, Stream);
1909
1910   // Emit information describing all of the types in the module.
1911   WriteTypeTable(VE, Stream);
1912
1913   // Emit top-level description of module, including target triple, inline asm,
1914   // descriptors for global variables, and function prototype info.
1915   WriteModuleInfo(M, VE, Stream);
1916
1917   // Emit constants.
1918   WriteModuleConstants(VE, Stream);
1919
1920   // Emit metadata.
1921   WriteModuleMetadata(M, VE, Stream);
1922
1923   // Emit metadata.
1924   WriteModuleMetadataStore(M, Stream);
1925
1926   // Emit names for globals/functions etc.
1927   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1928
1929   // Emit use-lists.
1930   if (EnablePreserveUseListOrdering)
1931     WriteModuleUseLists(M, VE, Stream);
1932
1933   // Emit function bodies.
1934   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1935     if (!F->isDeclaration())
1936       WriteFunction(*F, VE, Stream);
1937
1938   Stream.ExitBlock();
1939 }
1940
1941 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1942 /// header and trailer to make it compatible with the system archiver.  To do
1943 /// this we emit the following header, and then emit a trailer that pads the
1944 /// file out to be a multiple of 16 bytes.
1945 ///
1946 /// struct bc_header {
1947 ///   uint32_t Magic;         // 0x0B17C0DE
1948 ///   uint32_t Version;       // Version, currently always 0.
1949 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1950 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1951 ///   uint32_t CPUType;       // CPU specifier.
1952 ///   ... potentially more later ...
1953 /// };
1954 enum {
1955   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1956   DarwinBCHeaderSize = 5*4
1957 };
1958
1959 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1960                                uint32_t &Position) {
1961   Buffer[Position + 0] = (unsigned char) (Value >>  0);
1962   Buffer[Position + 1] = (unsigned char) (Value >>  8);
1963   Buffer[Position + 2] = (unsigned char) (Value >> 16);
1964   Buffer[Position + 3] = (unsigned char) (Value >> 24);
1965   Position += 4;
1966 }
1967
1968 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1969                                          const Triple &TT) {
1970   unsigned CPUType = ~0U;
1971
1972   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1973   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1974   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1975   // specific constants here because they are implicitly part of the Darwin ABI.
1976   enum {
1977     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1978     DARWIN_CPU_TYPE_X86        = 7,
1979     DARWIN_CPU_TYPE_ARM        = 12,
1980     DARWIN_CPU_TYPE_POWERPC    = 18
1981   };
1982
1983   Triple::ArchType Arch = TT.getArch();
1984   if (Arch == Triple::x86_64)
1985     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1986   else if (Arch == Triple::x86)
1987     CPUType = DARWIN_CPU_TYPE_X86;
1988   else if (Arch == Triple::ppc)
1989     CPUType = DARWIN_CPU_TYPE_POWERPC;
1990   else if (Arch == Triple::ppc64)
1991     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1992   else if (Arch == Triple::arm || Arch == Triple::thumb)
1993     CPUType = DARWIN_CPU_TYPE_ARM;
1994
1995   // Traditional Bitcode starts after header.
1996   assert(Buffer.size() >= DarwinBCHeaderSize &&
1997          "Expected header size to be reserved");
1998   unsigned BCOffset = DarwinBCHeaderSize;
1999   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2000
2001   // Write the magic and version.
2002   unsigned Position = 0;
2003   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2004   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2005   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2006   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2007   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2008
2009   // If the file is not a multiple of 16 bytes, insert dummy padding.
2010   while (Buffer.size() & 15)
2011     Buffer.push_back(0);
2012 }
2013
2014 /// WriteBitcodeToFile - Write the specified module to the specified output
2015 /// stream.
2016 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2017   SmallVector<char, 0> Buffer;
2018   Buffer.reserve(256*1024);
2019
2020   // If this is darwin or another generic macho target, reserve space for the
2021   // header.
2022   Triple TT(M->getTargetTriple());
2023   if (TT.isOSDarwin())
2024     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2025
2026   // Emit the module into the buffer.
2027   {
2028     BitstreamWriter Stream(Buffer);
2029
2030     // Emit the file header.
2031     Stream.Emit((unsigned)'B', 8);
2032     Stream.Emit((unsigned)'C', 8);
2033     Stream.Emit(0x0, 4);
2034     Stream.Emit(0xC, 4);
2035     Stream.Emit(0xE, 4);
2036     Stream.Emit(0xD, 4);
2037
2038     // Emit the module.
2039     WriteModule(M, Stream);
2040   }
2041
2042   if (TT.isOSDarwin())
2043     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2044
2045   // Write the generated bitstream to "Out".
2046   Out.write((char*)&Buffer.front(), Buffer.size());
2047 }