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::JumpTable:
 181     return bitc::ATTR_KIND_JUMP_TABLE;
 182   case Attribute::MinSize:
 183     return bitc::ATTR_KIND_MIN_SIZE;
 184   case Attribute::Naked:
 185     return bitc::ATTR_KIND_NAKED;
 186   case Attribute::Nest:
 187     return bitc::ATTR_KIND_NEST;
 188   case Attribute::NoAlias:
 189     return bitc::ATTR_KIND_NO_ALIAS;
 190   case Attribute::NoBuiltin:
 191     return bitc::ATTR_KIND_NO_BUILTIN;
 192   case Attribute::NoCapture:
 193     return bitc::ATTR_KIND_NO_CAPTURE;
 194   case Attribute::NoDuplicate:
 195     return bitc::ATTR_KIND_NO_DUPLICATE;
 196   case Attribute::NoImplicitFloat:
 197     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 198   case Attribute::NoInline:
 199     return bitc::ATTR_KIND_NO_INLINE;
 200   case Attribute::NonLazyBind:
 201     return bitc::ATTR_KIND_NON_LAZY_BIND;
 202   case Attribute::NonNull:
 203     return bitc::ATTR_KIND_NON_NULL;
 204   case Attribute::NoRedZone:
 205     return bitc::ATTR_KIND_NO_RED_ZONE;
 206   case Attribute::NoReturn:
 207     return bitc::ATTR_KIND_NO_RETURN;
 208   case Attribute::NoUnwind:
 209     return bitc::ATTR_KIND_NO_UNWIND;
 210   case Attribute::OptimizeForSize:
 211     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 212   case Attribute::OptimizeNone:
 213     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 214   case Attribute::ReadNone:
 215     return bitc::ATTR_KIND_READ_NONE;
 216   case Attribute::ReadOnly:
 217     return bitc::ATTR_KIND_READ_ONLY;
 218   case Attribute::Returned:
 219     return bitc::ATTR_KIND_RETURNED;
 220   case Attribute::ReturnsTwice:
 221     return bitc::ATTR_KIND_RETURNS_TWICE;
 222   case Attribute::SExt:
 223     return bitc::ATTR_KIND_S_EXT;
 224   case Attribute::StackAlignment:
 225     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 226   case Attribute::StackProtect:
 227     return bitc::ATTR_KIND_STACK_PROTECT;
 228   case Attribute::StackProtectReq:
 229     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 230   case Attribute::StackProtectStrong:
 231     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 232   case Attribute::StructRet:
 233     return bitc::ATTR_KIND_STRUCT_RET;
 234   case Attribute::SanitizeAddress:
 235     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 236   case Attribute::SanitizeThread:
 237     return bitc::ATTR_KIND_SANITIZE_THREAD;
 238   case Attribute::SanitizeMemory:
 239     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 240   case Attribute::UWTable:
 241     return bitc::ATTR_KIND_UW_TABLE;
 242   case Attribute::ZExt:
 243     return bitc::ATTR_KIND_Z_EXT;
 244   case Attribute::EndAttrKinds:
 245     llvm_unreachable("Can not encode end-attribute kinds marker.");
 246   case Attribute::None:
 247     llvm_unreachable("Can not encode none-attribute.");
 248   }
 249
 250   llvm_unreachable("Trying to encode unknown attribute");
 251 }
 252
 253 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 254                                      BitstreamWriter &Stream) {
 255   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 256   if (AttrGrps.empty()) return;
 257
 258   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 259
 260   SmallVector<uint64_t, 64> Record;
 261   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 262     AttributeSet AS = AttrGrps[i];
 263     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 264       AttributeSet A = AS.getSlotAttributes(i);
 265
 266       Record.push_back(VE.getAttributeGroupID(A));
 267       Record.push_back(AS.getSlotIndex(i));
 268
 269       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 270            I != E; ++I) {
 271         Attribute Attr = *I;
 272         if (Attr.isEnumAttribute()) {
 273           Record.push_back(0);
 274           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 275         } else if (Attr.isAlignAttribute()) {
 276           Record.push_back(1);
 277           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 278           Record.push_back(Attr.getValueAsInt());
 279         } else {
 280           StringRef Kind = Attr.getKindAsString();
 281           StringRef Val = Attr.getValueAsString();
 282
 283           Record.push_back(Val.empty() ? 3 : 4);
 284           Record.append(Kind.begin(), Kind.end());
 285           Record.push_back(0);
 286           if (!Val.empty()) {
 287             Record.append(Val.begin(), Val.end());
 288             Record.push_back(0);
 289           }
 290         }
 291       }
 292
 293       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 294       Record.clear();
 295     }
 296   }
 297
 298   Stream.ExitBlock();
 299 }
 300
 301 static void WriteAttributeTable(const ValueEnumerator &VE,
 302                                 BitstreamWriter &Stream) {
 303   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 304   if (Attrs.empty()) return;
 305
 306   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 307
 308   SmallVector<uint64_t, 64> Record;
 309   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 310     const AttributeSet &A = Attrs[i];
 311     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 312       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 313
 314     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 315     Record.clear();
 316   }
 317
 318   Stream.ExitBlock();
 319 }
 320
 321 /// WriteTypeTable - Write out the type table for a module.
 322 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 323   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 324
 325   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 326   SmallVector<uint64_t, 64> TypeVals;
 327
 328   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 329
 330   // Abbrev for TYPE_CODE_POINTER.
 331   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 332   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 334   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 335   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 336
 337   // Abbrev for TYPE_CODE_FUNCTION.
 338   Abbv = new BitCodeAbbrev();
 339   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 343
 344   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 345
 346   // Abbrev for TYPE_CODE_STRUCT_ANON.
 347   Abbv = new BitCodeAbbrev();
 348   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 349   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 352
 353   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 354
 355   // Abbrev for TYPE_CODE_STRUCT_NAME.
 356   Abbv = new BitCodeAbbrev();
 357   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 358   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 360   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 361
 362   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 363   Abbv = new BitCodeAbbrev();
 364   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 368
 369   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 370
 371   // Abbrev for TYPE_CODE_ARRAY.
 372   Abbv = new BitCodeAbbrev();
 373   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 374   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 375   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 376
 377   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 378
 379   // Emit an entry count so the reader can reserve space.
 380   TypeVals.push_back(TypeList.size());
 381   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 382   TypeVals.clear();
 383
 384   // Loop over all of the types, emitting each in turn.
 385   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 386     Type *T = TypeList[i];
 387     int AbbrevToUse = 0;
 388     unsigned Code = 0;
 389
 390     switch (T->getTypeID()) {
 391     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 392     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 393     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 394     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 395     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 396     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 397     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 398     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 399     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 400     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 401     case Type::IntegerTyID:
 402       // INTEGER: [width]
 403       Code = bitc::TYPE_CODE_INTEGER;
 404       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 405       break;
 406     case Type::PointerTyID: {
 407       PointerType *PTy = cast<PointerType>(T);
 408       // POINTER: [pointee type, address space]
 409       Code = bitc::TYPE_CODE_POINTER;
 410       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 411       unsigned AddressSpace = PTy->getAddressSpace();
 412       TypeVals.push_back(AddressSpace);
 413       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 414       break;
 415     }
 416     case Type::FunctionTyID: {
 417       FunctionType *FT = cast<FunctionType>(T);
 418       // FUNCTION: [isvararg, retty, paramty x N]
 419       Code = bitc::TYPE_CODE_FUNCTION;
 420       TypeVals.push_back(FT->isVarArg());
 421       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 422       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 423         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 424       AbbrevToUse = FunctionAbbrev;
 425       break;
 426     }
 427     case Type::StructTyID: {
 428       StructType *ST = cast<StructType>(T);
 429       // STRUCT: [ispacked, eltty x N]
 430       TypeVals.push_back(ST->isPacked());
 431       // Output all of the element types.
 432       for (StructType::element_iterator I = ST->element_begin(),
 433            E = ST->element_end(); I != E; ++I)
 434         TypeVals.push_back(VE.getTypeID(*I));
 435
 436       if (ST->isLiteral()) {
 437         Code = bitc::TYPE_CODE_STRUCT_ANON;
 438         AbbrevToUse = StructAnonAbbrev;
 439       } else {
 440         if (ST->isOpaque()) {
 441           Code = bitc::TYPE_CODE_OPAQUE;
 442         } else {
 443           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 444           AbbrevToUse = StructNamedAbbrev;
 445         }
 446
 447         // Emit the name if it is present.
 448         if (!ST->getName().empty())
 449           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 450                             StructNameAbbrev, Stream);
 451       }
 452       break;
 453     }
 454     case Type::ArrayTyID: {
 455       ArrayType *AT = cast<ArrayType>(T);
 456       // ARRAY: [numelts, eltty]
 457       Code = bitc::TYPE_CODE_ARRAY;
 458       TypeVals.push_back(AT->getNumElements());
 459       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 460       AbbrevToUse = ArrayAbbrev;
 461       break;
 462     }
 463     case Type::VectorTyID: {
 464       VectorType *VT = cast<VectorType>(T);
 465       // VECTOR [numelts, eltty]
 466       Code = bitc::TYPE_CODE_VECTOR;
 467       TypeVals.push_back(VT->getNumElements());
 468       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 469       break;
 470     }
 471     }
 472
 473     // Emit the finished record.
 474     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 475     TypeVals.clear();
 476   }
 477
 478   Stream.ExitBlock();
 479 }
 480
 481 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 482   switch (GV.getLinkage()) {
 483   case GlobalValue::ExternalLinkage:                 return 0;
 484   case GlobalValue::WeakAnyLinkage:                  return 1;
 485   case GlobalValue::AppendingLinkage:                return 2;
 486   case GlobalValue::InternalLinkage:                 return 3;
 487   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 488   case GlobalValue::ExternalWeakLinkage:             return 7;
 489   case GlobalValue::CommonLinkage:                   return 8;
 490   case GlobalValue::PrivateLinkage:                  return 9;
 491   case GlobalValue::WeakODRLinkage:                  return 10;
 492   case GlobalValue::LinkOnceODRLinkage:              return 11;
 493   case GlobalValue::AvailableExternallyLinkage:      return 12;
 494   }
 495   llvm_unreachable("Invalid linkage");
 496 }
 497
 498 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 499   switch (GV.getVisibility()) {
 500   case GlobalValue::DefaultVisibility:   return 0;
 501   case GlobalValue::HiddenVisibility:    return 1;
 502   case GlobalValue::ProtectedVisibility: return 2;
 503   }
 504   llvm_unreachable("Invalid visibility");
 505 }
 506
 507 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 508   switch (GV.getDLLStorageClass()) {
 509   case GlobalValue::DefaultStorageClass:   return 0;
 510   case GlobalValue::DLLImportStorageClass: return 1;
 511   case GlobalValue::DLLExportStorageClass: return 2;
 512   }
 513   llvm_unreachable("Invalid DLL storage class");
 514 }
 515
 516 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 517   switch (GV.getThreadLocalMode()) {
 518     case GlobalVariable::NotThreadLocal:         return 0;
 519     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 520     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 521     case GlobalVariable::InitialExecTLSModel:    return 3;
 522     case GlobalVariable::LocalExecTLSModel:      return 4;
 523   }
 524   llvm_unreachable("Invalid TLS model");
 525 }
 526
 527 // Emit top-level description of module, including target triple, inline asm,
 528 // descriptors for global variables, and function prototype info.
 529 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 530                             BitstreamWriter &Stream) {
 531   // Emit various pieces of data attached to a module.
 532   if (!M->getTargetTriple().empty())
 533     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 534                       0/*TODO*/, Stream);
 535   const std::string &DL = M->getDataLayoutStr();
 536   if (!DL.empty())
 537     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 538   if (!M->getModuleInlineAsm().empty())
 539     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 540                       0/*TODO*/, Stream);
 541
 542   // Emit information about sections and GC, computing how many there are. Also
 543   // compute the maximum alignment value.
 544   std::map<std::string, unsigned> SectionMap;
 545   std::map<std::string, unsigned> GCMap;
 546   unsigned MaxAlignment = 0;
 547   unsigned MaxGlobalType = 0;
 548   for (const GlobalValue &GV : M->globals()) {
 549     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 550     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 551     if (GV.hasSection()) {
 552       // Give section names unique ID's.
 553       unsigned &Entry = SectionMap[GV.getSection()];
 554       if (!Entry) {
 555         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 556                           0/*TODO*/, Stream);
 557         Entry = SectionMap.size();
 558       }
 559     }
 560   }
 561   for (const Function &F : *M) {
 562     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 563     if (F.hasSection()) {
 564       // Give section names unique ID's.
 565       unsigned &Entry = SectionMap[F.getSection()];
 566       if (!Entry) {
 567         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 568                           0/*TODO*/, Stream);
 569         Entry = SectionMap.size();
 570       }
 571     }
 572     if (F.hasGC()) {
 573       // Same for GC names.
 574       unsigned &Entry = GCMap[F.getGC()];
 575       if (!Entry) {
 576         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 577                           0/*TODO*/, Stream);
 578         Entry = GCMap.size();
 579       }
 580     }
 581   }
 582
 583   // Emit abbrev for globals, now that we know # sections and max alignment.
 584   unsigned SimpleGVarAbbrev = 0;
 585   if (!M->global_empty()) {
 586     // Add an abbrev for common globals with no visibility or thread localness.
 587     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 588     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 590                               Log2_32_Ceil(MaxGlobalType+1)));
 591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 594     if (MaxAlignment == 0)                                      // Alignment.
 595       Abbv->Add(BitCodeAbbrevOp(0));
 596     else {
 597       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 598       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 599                                Log2_32_Ceil(MaxEncAlignment+1)));
 600     }
 601     if (SectionMap.empty())                                    // Section.
 602       Abbv->Add(BitCodeAbbrevOp(0));
 603     else
 604       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 605                                Log2_32_Ceil(SectionMap.size()+1)));
 606     // Don't bother emitting vis + thread local.
 607     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 608   }
 609
 610   // Emit the global variable information.
 611   SmallVector<unsigned, 64> Vals;
 612   for (const GlobalVariable &GV : M->globals()) {
 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 (const Function &F : *M) {
 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 (const GlobalAlias &A : M->aliases()) {
 667     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 668     Vals.push_back(VE.getTypeID(A.getType()));
 669     Vals.push_back(VE.getValueID(A.getAliasee()));
 670     Vals.push_back(getEncodedLinkage(A));
 671     Vals.push_back(getEncodedVisibility(A));
 672     Vals.push_back(getEncodedDLLStorageClass(A));
 673     Vals.push_back(getEncodedThreadLocalMode(A));
 674     Vals.push_back(A.hasUnnamedAddr());
 675     unsigned AbbrevToUse = 0;
 676     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 677     Vals.clear();
 678   }
 679 }
 680
 681 static uint64_t GetOptimizationFlags(const Value *V) {
 682   uint64_t Flags = 0;
 683
 684   if (const OverflowingBinaryOperator *OBO =
 685         dyn_cast<OverflowingBinaryOperator>(V)) {
 686     if (OBO->hasNoSignedWrap())
 687       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 688     if (OBO->hasNoUnsignedWrap())
 689       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 690   } else if (const PossiblyExactOperator *PEO =
 691                dyn_cast<PossiblyExactOperator>(V)) {
 692     if (PEO->isExact())
 693       Flags |= 1 << bitc::PEO_EXACT;
 694   } else if (const FPMathOperator *FPMO =
 695              dyn_cast<const FPMathOperator>(V)) {
 696     if (FPMO->hasUnsafeAlgebra())
 697       Flags |= FastMathFlags::UnsafeAlgebra;
 698     if (FPMO->hasNoNaNs())
 699       Flags |= FastMathFlags::NoNaNs;
 700     if (FPMO->hasNoInfs())
 701       Flags |= FastMathFlags::NoInfs;
 702     if (FPMO->hasNoSignedZeros())
 703       Flags |= FastMathFlags::NoSignedZeros;
 704     if (FPMO->hasAllowReciprocal())
 705       Flags |= FastMathFlags::AllowReciprocal;
 706   }
 707
 708   return Flags;
 709 }
 710
 711 static void WriteMDNode(const MDNode *N,
 712                         const ValueEnumerator &VE,
 713                         BitstreamWriter &Stream,
 714                         SmallVectorImpl<uint64_t> &Record) {
 715   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 716     if (N->getOperand(i)) {
 717       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 718       Record.push_back(VE.getValueID(N->getOperand(i)));
 719     } else {
 720       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 721       Record.push_back(0);
 722     }
 723   }
 724   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 725                                            bitc::METADATA_NODE;
 726   Stream.EmitRecord(MDCode, Record, 0);
 727   Record.clear();
 728 }
 729
 730 static void WriteModuleMetadata(const Module *M,
 731                                 const ValueEnumerator &VE,
 732                                 BitstreamWriter &Stream) {
 733   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 734   bool StartedMetadataBlock = false;
 735   unsigned MDSAbbrev = 0;
 736   SmallVector<uint64_t, 64> Record;
 737   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 738
 739     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 740       if (!N->isFunctionLocal() || !N->getFunction()) {
 741         if (!StartedMetadataBlock) {
 742           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 743           StartedMetadataBlock = true;
 744         }
 745         WriteMDNode(N, VE, Stream, Record);
 746       }
 747     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 748       if (!StartedMetadataBlock)  {
 749         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 750
 751         // Abbrev for METADATA_STRING.
 752         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 753         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 754         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 755         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 756         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 757         StartedMetadataBlock = true;
 758       }
 759
 760       // Code: [strchar x N]
 761       Record.append(MDS->begin(), MDS->end());
 762
 763       // Emit the finished record.
 764       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 765       Record.clear();
 766     }
 767   }
 768
 769   // Write named metadata.
 770   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 771        E = M->named_metadata_end(); I != E; ++I) {
 772     const NamedMDNode *NMD = I;
 773     if (!StartedMetadataBlock)  {
 774       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 775       StartedMetadataBlock = true;
 776     }
 777
 778     // Write name.
 779     StringRef Str = NMD->getName();
 780     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 781       Record.push_back(Str[i]);
 782     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 783     Record.clear();
 784
 785     // Write named metadata operands.
 786     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 787       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 788     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 789     Record.clear();
 790   }
 791
 792   if (StartedMetadataBlock)
 793     Stream.ExitBlock();
 794 }
 795
 796 static void WriteFunctionLocalMetadata(const Function &F,
 797                                        const ValueEnumerator &VE,
 798                                        BitstreamWriter &Stream) {
 799   bool StartedMetadataBlock = false;
 800   SmallVector<uint64_t, 64> Record;
 801   const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
 802   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 803     if (const MDNode *N = Vals[i])
 804       if (N->isFunctionLocal() && N->getFunction() == &F) {
 805         if (!StartedMetadataBlock) {
 806           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 807           StartedMetadataBlock = true;
 808         }
 809         WriteMDNode(N, VE, Stream, Record);
 810       }
 811
 812   if (StartedMetadataBlock)
 813     Stream.ExitBlock();
 814 }
 815
 816 static void WriteMetadataAttachment(const Function &F,
 817                                     const ValueEnumerator &VE,
 818                                     BitstreamWriter &Stream) {
 819   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 820
 821   SmallVector<uint64_t, 64> Record;
 822
 823   // Write metadata attachments
 824   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 825   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 826
 827   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 828     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 829          I != E; ++I) {
 830       MDs.clear();
 831       I->getAllMetadataOtherThanDebugLoc(MDs);
 832
 833       // If no metadata, ignore instruction.
 834       if (MDs.empty()) continue;
 835
 836       Record.push_back(VE.getInstructionID(I));
 837
 838       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 839         Record.push_back(MDs[i].first);
 840         Record.push_back(VE.getValueID(MDs[i].second));
 841       }
 842       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 843       Record.clear();
 844     }
 845
 846   Stream.ExitBlock();
 847 }
 848
 849 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 850   SmallVector<uint64_t, 64> Record;
 851
 852   // Write metadata kinds
 853   // METADATA_KIND - [n x [id, name]]
 854   SmallVector<StringRef, 8> Names;
 855   M->getMDKindNames(Names);
 856
 857   if (Names.empty()) return;
 858
 859   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 860
 861   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 862     Record.push_back(MDKindID);
 863     StringRef KName = Names[MDKindID];
 864     Record.append(KName.begin(), KName.end());
 865
 866     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 867     Record.clear();
 868   }
 869
 870   Stream.ExitBlock();
 871 }
 872
 873 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 874   if ((int64_t)V >= 0)
 875     Vals.push_back(V << 1);
 876   else
 877     Vals.push_back((-V << 1) | 1);
 878 }
 879
 880 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 881                            const ValueEnumerator &VE,
 882                            BitstreamWriter &Stream, bool isGlobal) {
 883   if (FirstVal == LastVal) return;
 884
 885   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 886
 887   unsigned AggregateAbbrev = 0;
 888   unsigned String8Abbrev = 0;
 889   unsigned CString7Abbrev = 0;
 890   unsigned CString6Abbrev = 0;
 891   // If this is a constant pool for the module, emit module-specific abbrevs.
 892   if (isGlobal) {
 893     // Abbrev for CST_CODE_AGGREGATE.
 894     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 895     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 897     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 898     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 899
 900     // Abbrev for CST_CODE_STRING.
 901     Abbv = new BitCodeAbbrev();
 902     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 903     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 904     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 905     String8Abbrev = Stream.EmitAbbrev(Abbv);
 906     // Abbrev for CST_CODE_CSTRING.
 907     Abbv = new BitCodeAbbrev();
 908     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 909     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 910     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 911     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 912     // Abbrev for CST_CODE_CSTRING.
 913     Abbv = new BitCodeAbbrev();
 914     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 915     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 916     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 917     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 918   }
 919
 920   SmallVector<uint64_t, 64> Record;
 921
 922   const ValueEnumerator::ValueList &Vals = VE.getValues();
 923   Type *LastTy = nullptr;
 924   for (unsigned i = FirstVal; i != LastVal; ++i) {
 925     const Value *V = Vals[i].first;
 926     // If we need to switch types, do so now.
 927     if (V->getType() != LastTy) {
 928       LastTy = V->getType();
 929       Record.push_back(VE.getTypeID(LastTy));
 930       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 931                         CONSTANTS_SETTYPE_ABBREV);
 932       Record.clear();
 933     }
 934
 935     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 936       Record.push_back(unsigned(IA->hasSideEffects()) |
 937                        unsigned(IA->isAlignStack()) << 1 |
 938                        unsigned(IA->getDialect()&1) << 2);
 939
 940       // Add the asm string.
 941       const std::string &AsmStr = IA->getAsmString();
 942       Record.push_back(AsmStr.size());
 943       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 944         Record.push_back(AsmStr[i]);
 945
 946       // Add the constraint string.
 947       const std::string &ConstraintStr = IA->getConstraintString();
 948       Record.push_back(ConstraintStr.size());
 949       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 950         Record.push_back(ConstraintStr[i]);
 951       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 952       Record.clear();
 953       continue;
 954     }
 955     const Constant *C = cast<Constant>(V);
 956     unsigned Code = -1U;
 957     unsigned AbbrevToUse = 0;
 958     if (C->isNullValue()) {
 959       Code = bitc::CST_CODE_NULL;
 960     } else if (isa<UndefValue>(C)) {
 961       Code = bitc::CST_CODE_UNDEF;
 962     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 963       if (IV->getBitWidth() <= 64) {
 964         uint64_t V = IV->getSExtValue();
 965         emitSignedInt64(Record, V);
 966         Code = bitc::CST_CODE_INTEGER;
 967         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 968       } else {                             // Wide integers, > 64 bits in size.
 969         // We have an arbitrary precision integer value to write whose
 970         // bit width is > 64. However, in canonical unsigned integer
 971         // format it is likely that the high bits are going to be zero.
 972         // So, we only write the number of active words.
 973         unsigned NWords = IV->getValue().getActiveWords();
 974         const uint64_t *RawWords = IV->getValue().getRawData();
 975         for (unsigned i = 0; i != NWords; ++i) {
 976           emitSignedInt64(Record, RawWords[i]);
 977         }
 978         Code = bitc::CST_CODE_WIDE_INTEGER;
 979       }
 980     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 981       Code = bitc::CST_CODE_FLOAT;
 982       Type *Ty = CFP->getType();
 983       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
 984         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 985       } else if (Ty->isX86_FP80Ty()) {
 986         // api needed to prevent premature destruction
 987         // bits are not in the same order as a normal i80 APInt, compensate.
 988         APInt api = CFP->getValueAPF().bitcastToAPInt();
 989         const uint64_t *p = api.getRawData();
 990         Record.push_back((p[1] << 48) | (p[0] >> 16));
 991         Record.push_back(p[0] & 0xffffLL);
 992       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 993         APInt api = CFP->getValueAPF().bitcastToAPInt();
 994         const uint64_t *p = api.getRawData();
 995         Record.push_back(p[0]);
 996         Record.push_back(p[1]);
 997       } else {
 998         assert (0 && "Unknown FP type!");
 999       }
1000     } else if (isa<ConstantDataSequential>(C) &&
1001                cast<ConstantDataSequential>(C)->isString()) {
1002       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1003       // Emit constant strings specially.
1004       unsigned NumElts = Str->getNumElements();
1005       // If this is a null-terminated string, use the denser CSTRING encoding.
1006       if (Str->isCString()) {
1007         Code = bitc::CST_CODE_CSTRING;
1008         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1009       } else {
1010         Code = bitc::CST_CODE_STRING;
1011         AbbrevToUse = String8Abbrev;
1012       }
1013       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1014       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1015       for (unsigned i = 0; i != NumElts; ++i) {
1016         unsigned char V = Str->getElementAsInteger(i);
1017         Record.push_back(V);
1018         isCStr7 &= (V & 128) == 0;
1019         if (isCStrChar6)
1020           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1021       }
1022
1023       if (isCStrChar6)
1024         AbbrevToUse = CString6Abbrev;
1025       else if (isCStr7)
1026         AbbrevToUse = CString7Abbrev;
1027     } else if (const ConstantDataSequential *CDS =
1028                   dyn_cast<ConstantDataSequential>(C)) {
1029       Code = bitc::CST_CODE_DATA;
1030       Type *EltTy = CDS->getType()->getElementType();
1031       if (isa<IntegerType>(EltTy)) {
1032         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1033           Record.push_back(CDS->getElementAsInteger(i));
1034       } else if (EltTy->isFloatTy()) {
1035         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1036           union { float F; uint32_t I; };
1037           F = CDS->getElementAsFloat(i);
1038           Record.push_back(I);
1039         }
1040       } else {
1041         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1042         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1043           union { double F; uint64_t I; };
1044           F = CDS->getElementAsDouble(i);
1045           Record.push_back(I);
1046         }
1047       }
1048     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1049                isa<ConstantVector>(C)) {
1050       Code = bitc::CST_CODE_AGGREGATE;
1051       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1052         Record.push_back(VE.getValueID(C->getOperand(i)));
1053       AbbrevToUse = AggregateAbbrev;
1054     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1055       switch (CE->getOpcode()) {
1056       default:
1057         if (Instruction::isCast(CE->getOpcode())) {
1058           Code = bitc::CST_CODE_CE_CAST;
1059           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1060           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1061           Record.push_back(VE.getValueID(C->getOperand(0)));
1062           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1063         } else {
1064           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1065           Code = bitc::CST_CODE_CE_BINOP;
1066           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1067           Record.push_back(VE.getValueID(C->getOperand(0)));
1068           Record.push_back(VE.getValueID(C->getOperand(1)));
1069           uint64_t Flags = GetOptimizationFlags(CE);
1070           if (Flags != 0)
1071             Record.push_back(Flags);
1072         }
1073         break;
1074       case Instruction::GetElementPtr:
1075         Code = bitc::CST_CODE_CE_GEP;
1076         if (cast<GEPOperator>(C)->isInBounds())
1077           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1078         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1079           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1080           Record.push_back(VE.getValueID(C->getOperand(i)));
1081         }
1082         break;
1083       case Instruction::Select:
1084         Code = bitc::CST_CODE_CE_SELECT;
1085         Record.push_back(VE.getValueID(C->getOperand(0)));
1086         Record.push_back(VE.getValueID(C->getOperand(1)));
1087         Record.push_back(VE.getValueID(C->getOperand(2)));
1088         break;
1089       case Instruction::ExtractElement:
1090         Code = bitc::CST_CODE_CE_EXTRACTELT;
1091         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1092         Record.push_back(VE.getValueID(C->getOperand(0)));
1093         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1094         Record.push_back(VE.getValueID(C->getOperand(1)));
1095         break;
1096       case Instruction::InsertElement:
1097         Code = bitc::CST_CODE_CE_INSERTELT;
1098         Record.push_back(VE.getValueID(C->getOperand(0)));
1099         Record.push_back(VE.getValueID(C->getOperand(1)));
1100         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1101         Record.push_back(VE.getValueID(C->getOperand(2)));
1102         break;
1103       case Instruction::ShuffleVector:
1104         // If the return type and argument types are the same, this is a
1105         // standard shufflevector instruction.  If the types are different,
1106         // then the shuffle is widening or truncating the input vectors, and
1107         // the argument type must also be encoded.
1108         if (C->getType() == C->getOperand(0)->getType()) {
1109           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1110         } else {
1111           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1112           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1113         }
1114         Record.push_back(VE.getValueID(C->getOperand(0)));
1115         Record.push_back(VE.getValueID(C->getOperand(1)));
1116         Record.push_back(VE.getValueID(C->getOperand(2)));
1117         break;
1118       case Instruction::ICmp:
1119       case Instruction::FCmp:
1120         Code = bitc::CST_CODE_CE_CMP;
1121         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1122         Record.push_back(VE.getValueID(C->getOperand(0)));
1123         Record.push_back(VE.getValueID(C->getOperand(1)));
1124         Record.push_back(CE->getPredicate());
1125         break;
1126       }
1127     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1128       Code = bitc::CST_CODE_BLOCKADDRESS;
1129       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1130       Record.push_back(VE.getValueID(BA->getFunction()));
1131       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1132     } else {
1133 #ifndef NDEBUG
1134       C->dump();
1135 #endif
1136       llvm_unreachable("Unknown constant!");
1137     }
1138     Stream.EmitRecord(Code, Record, AbbrevToUse);
1139     Record.clear();
1140   }
1141
1142   Stream.ExitBlock();
1143 }
1144
1145 static void WriteModuleConstants(const ValueEnumerator &VE,
1146                                  BitstreamWriter &Stream) {
1147   const ValueEnumerator::ValueList &Vals = VE.getValues();
1148
1149   // Find the first constant to emit, which is the first non-globalvalue value.
1150   // We know globalvalues have been emitted by WriteModuleInfo.
1151   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1152     if (!isa<GlobalValue>(Vals[i].first)) {
1153       WriteConstants(i, Vals.size(), VE, Stream, true);
1154       return;
1155     }
1156   }
1157 }
1158
1159 /// PushValueAndType - The file has to encode both the value and type id for
1160 /// many values, because we need to know what type to create for forward
1161 /// references.  However, most operands are not forward references, so this type
1162 /// field is not needed.
1163 ///
1164 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1165 /// instruction ID, then it is a forward reference, and it also includes the
1166 /// type ID.  The value ID that is written is encoded relative to the InstID.
1167 static bool PushValueAndType(const Value *V, unsigned InstID,
1168                              SmallVectorImpl<unsigned> &Vals,
1169                              ValueEnumerator &VE) {
1170   unsigned ValID = VE.getValueID(V);
1171   // Make encoding relative to the InstID.
1172   Vals.push_back(InstID - ValID);
1173   if (ValID >= InstID) {
1174     Vals.push_back(VE.getTypeID(V->getType()));
1175     return true;
1176   }
1177   return false;
1178 }
1179
1180 /// pushValue - Like PushValueAndType, but where the type of the value is
1181 /// omitted (perhaps it was already encoded in an earlier operand).
1182 static void pushValue(const Value *V, unsigned InstID,
1183                       SmallVectorImpl<unsigned> &Vals,
1184                       ValueEnumerator &VE) {
1185   unsigned ValID = VE.getValueID(V);
1186   Vals.push_back(InstID - ValID);
1187 }
1188
1189 static void pushValueSigned(const Value *V, unsigned InstID,
1190                             SmallVectorImpl<uint64_t> &Vals,
1191                             ValueEnumerator &VE) {
1192   unsigned ValID = VE.getValueID(V);
1193   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1194   emitSignedInt64(Vals, diff);
1195 }
1196
1197 /// WriteInstruction - Emit an instruction to the specified stream.
1198 static void WriteInstruction(const Instruction &I, unsigned InstID,
1199                              ValueEnumerator &VE, BitstreamWriter &Stream,
1200                              SmallVectorImpl<unsigned> &Vals) {
1201   unsigned Code = 0;
1202   unsigned AbbrevToUse = 0;
1203   VE.setInstructionID(&I);
1204   switch (I.getOpcode()) {
1205   default:
1206     if (Instruction::isCast(I.getOpcode())) {
1207       Code = bitc::FUNC_CODE_INST_CAST;
1208       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1209         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1210       Vals.push_back(VE.getTypeID(I.getType()));
1211       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1212     } else {
1213       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1214       Code = bitc::FUNC_CODE_INST_BINOP;
1215       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1216         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1217       pushValue(I.getOperand(1), InstID, Vals, VE);
1218       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1219       uint64_t Flags = GetOptimizationFlags(&I);
1220       if (Flags != 0) {
1221         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1222           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1223         Vals.push_back(Flags);
1224       }
1225     }
1226     break;
1227
1228   case Instruction::GetElementPtr:
1229     Code = bitc::FUNC_CODE_INST_GEP;
1230     if (cast<GEPOperator>(&I)->isInBounds())
1231       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1232     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1233       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1234     break;
1235   case Instruction::ExtractValue: {
1236     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1237     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1238     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1239     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1240       Vals.push_back(*i);
1241     break;
1242   }
1243   case Instruction::InsertValue: {
1244     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1245     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1246     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1247     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1248     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1249       Vals.push_back(*i);
1250     break;
1251   }
1252   case Instruction::Select:
1253     Code = bitc::FUNC_CODE_INST_VSELECT;
1254     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1255     pushValue(I.getOperand(2), InstID, Vals, VE);
1256     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1257     break;
1258   case Instruction::ExtractElement:
1259     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1260     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1261     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1262     break;
1263   case Instruction::InsertElement:
1264     Code = bitc::FUNC_CODE_INST_INSERTELT;
1265     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1266     pushValue(I.getOperand(1), InstID, Vals, VE);
1267     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1268     break;
1269   case Instruction::ShuffleVector:
1270     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1271     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1272     pushValue(I.getOperand(1), InstID, Vals, VE);
1273     pushValue(I.getOperand(2), InstID, Vals, VE);
1274     break;
1275   case Instruction::ICmp:
1276   case Instruction::FCmp:
1277     // compare returning Int1Ty or vector of Int1Ty
1278     Code = bitc::FUNC_CODE_INST_CMP2;
1279     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1280     pushValue(I.getOperand(1), InstID, Vals, VE);
1281     Vals.push_back(cast<CmpInst>(I).getPredicate());
1282     break;
1283
1284   case Instruction::Ret:
1285     {
1286       Code = bitc::FUNC_CODE_INST_RET;
1287       unsigned NumOperands = I.getNumOperands();
1288       if (NumOperands == 0)
1289         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1290       else if (NumOperands == 1) {
1291         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1292           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1293       } else {
1294         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1295           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1296       }
1297     }
1298     break;
1299   case Instruction::Br:
1300     {
1301       Code = bitc::FUNC_CODE_INST_BR;
1302       const BranchInst &II = cast<BranchInst>(I);
1303       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1304       if (II.isConditional()) {
1305         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1306         pushValue(II.getCondition(), InstID, Vals, VE);
1307       }
1308     }
1309     break;
1310   case Instruction::Switch:
1311     {
1312       Code = bitc::FUNC_CODE_INST_SWITCH;
1313       const SwitchInst &SI = cast<SwitchInst>(I);
1314       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1315       pushValue(SI.getCondition(), InstID, Vals, VE);
1316       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1317       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1318            i != e; ++i) {
1319         Vals.push_back(VE.getValueID(i.getCaseValue()));
1320         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1321       }
1322     }
1323     break;
1324   case Instruction::IndirectBr:
1325     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1326     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1327     // Encode the address operand as relative, but not the basic blocks.
1328     pushValue(I.getOperand(0), InstID, Vals, VE);
1329     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1330       Vals.push_back(VE.getValueID(I.getOperand(i)));
1331     break;
1332
1333   case Instruction::Invoke: {
1334     const InvokeInst *II = cast<InvokeInst>(&I);
1335     const Value *Callee(II->getCalledValue());
1336     PointerType *PTy = cast<PointerType>(Callee->getType());
1337     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1338     Code = bitc::FUNC_CODE_INST_INVOKE;
1339
1340     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1341     Vals.push_back(II->getCallingConv());
1342     Vals.push_back(VE.getValueID(II->getNormalDest()));
1343     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1344     PushValueAndType(Callee, InstID, Vals, VE);
1345
1346     // Emit value #'s for the fixed parameters.
1347     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1348       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1349
1350     // Emit type/value pairs for varargs params.
1351     if (FTy->isVarArg()) {
1352       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1353            i != e; ++i)
1354         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1355     }
1356     break;
1357   }
1358   case Instruction::Resume:
1359     Code = bitc::FUNC_CODE_INST_RESUME;
1360     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1361     break;
1362   case Instruction::Unreachable:
1363     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1364     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1365     break;
1366
1367   case Instruction::PHI: {
1368     const PHINode &PN = cast<PHINode>(I);
1369     Code = bitc::FUNC_CODE_INST_PHI;
1370     // With the newer instruction encoding, forward references could give
1371     // negative valued IDs.  This is most common for PHIs, so we use
1372     // signed VBRs.
1373     SmallVector<uint64_t, 128> Vals64;
1374     Vals64.push_back(VE.getTypeID(PN.getType()));
1375     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1376       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1377       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1378     }
1379     // Emit a Vals64 vector and exit.
1380     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1381     Vals64.clear();
1382     return;
1383   }
1384
1385   case Instruction::LandingPad: {
1386     const LandingPadInst &LP = cast<LandingPadInst>(I);
1387     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1388     Vals.push_back(VE.getTypeID(LP.getType()));
1389     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1390     Vals.push_back(LP.isCleanup());
1391     Vals.push_back(LP.getNumClauses());
1392     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1393       if (LP.isCatch(I))
1394         Vals.push_back(LandingPadInst::Catch);
1395       else
1396         Vals.push_back(LandingPadInst::Filter);
1397       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1398     }
1399     break;
1400   }
1401
1402   case Instruction::Alloca:
1403     Code = bitc::FUNC_CODE_INST_ALLOCA;
1404     Vals.push_back(VE.getTypeID(I.getType()));
1405     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1406     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1407     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1408     break;
1409
1410   case Instruction::Load:
1411     if (cast<LoadInst>(I).isAtomic()) {
1412       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1413       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1414     } else {
1415       Code = bitc::FUNC_CODE_INST_LOAD;
1416       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1417         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1418     }
1419     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1420     Vals.push_back(cast<LoadInst>(I).isVolatile());
1421     if (cast<LoadInst>(I).isAtomic()) {
1422       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1423       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1424     }
1425     break;
1426   case Instruction::Store:
1427     if (cast<StoreInst>(I).isAtomic())
1428       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1429     else
1430       Code = bitc::FUNC_CODE_INST_STORE;
1431     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1432     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1433     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1434     Vals.push_back(cast<StoreInst>(I).isVolatile());
1435     if (cast<StoreInst>(I).isAtomic()) {
1436       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1437       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1438     }
1439     break;
1440   case Instruction::AtomicCmpXchg:
1441     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1442     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1443     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1444     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1445     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1446     Vals.push_back(GetEncodedOrdering(
1447                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1448     Vals.push_back(GetEncodedSynchScope(
1449                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1450     Vals.push_back(GetEncodedOrdering(
1451                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1452     break;
1453   case Instruction::AtomicRMW:
1454     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1455     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1456     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1457     Vals.push_back(GetEncodedRMWOperation(
1458                      cast<AtomicRMWInst>(I).getOperation()));
1459     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1460     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1461     Vals.push_back(GetEncodedSynchScope(
1462                      cast<AtomicRMWInst>(I).getSynchScope()));
1463     break;
1464   case Instruction::Fence:
1465     Code = bitc::FUNC_CODE_INST_FENCE;
1466     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1467     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1468     break;
1469   case Instruction::Call: {
1470     const CallInst &CI = cast<CallInst>(I);
1471     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1472     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1473
1474     Code = bitc::FUNC_CODE_INST_CALL;
1475
1476     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1477     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1478                    unsigned(CI.isMustTailCall()) << 14);
1479     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1480
1481     // Emit value #'s for the fixed parameters.
1482     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1483       // Check for labels (can happen with asm labels).
1484       if (FTy->getParamType(i)->isLabelTy())
1485         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1486       else
1487         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1488     }
1489
1490     // Emit type/value pairs for varargs params.
1491     if (FTy->isVarArg()) {
1492       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1493            i != e; ++i)
1494         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1495     }
1496     break;
1497   }
1498   case Instruction::VAArg:
1499     Code = bitc::FUNC_CODE_INST_VAARG;
1500     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1501     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1502     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1503     break;
1504   }
1505
1506   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1507   Vals.clear();
1508 }
1509
1510 // Emit names for globals/functions etc.
1511 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1512                                   const ValueEnumerator &VE,
1513                                   BitstreamWriter &Stream) {
1514   if (VST.empty()) return;
1515   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1516
1517   // FIXME: Set up the abbrev, we know how many values there are!
1518   // FIXME: We know if the type names can use 7-bit ascii.
1519   SmallVector<unsigned, 64> NameVals;
1520
1521   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1522        SI != SE; ++SI) {
1523
1524     const ValueName &Name = *SI;
1525
1526     // Figure out the encoding to use for the name.
1527     bool is7Bit = true;
1528     bool isChar6 = true;
1529     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1530          C != E; ++C) {
1531       if (isChar6)
1532         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1533       if ((unsigned char)*C & 128) {
1534         is7Bit = false;
1535         break;  // don't bother scanning the rest.
1536       }
1537     }
1538
1539     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1540
1541     // VST_ENTRY:   [valueid, namechar x N]
1542     // VST_BBENTRY: [bbid, namechar x N]
1543     unsigned Code;
1544     if (isa<BasicBlock>(SI->getValue())) {
1545       Code = bitc::VST_CODE_BBENTRY;
1546       if (isChar6)
1547         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1548     } else {
1549       Code = bitc::VST_CODE_ENTRY;
1550       if (isChar6)
1551         AbbrevToUse = VST_ENTRY_6_ABBREV;
1552       else if (is7Bit)
1553         AbbrevToUse = VST_ENTRY_7_ABBREV;
1554     }
1555
1556     NameVals.push_back(VE.getValueID(SI->getValue()));
1557     for (const char *P = Name.getKeyData(),
1558          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1559       NameVals.push_back((unsigned char)*P);
1560
1561     // Emit the finished record.
1562     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1563     NameVals.clear();
1564   }
1565   Stream.ExitBlock();
1566 }
1567
1568 /// WriteFunction - Emit a function body to the module stream.
1569 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1570                           BitstreamWriter &Stream) {
1571   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1572   VE.incorporateFunction(F);
1573
1574   SmallVector<unsigned, 64> Vals;
1575
1576   // Emit the number of basic blocks, so the reader can create them ahead of
1577   // time.
1578   Vals.push_back(VE.getBasicBlocks().size());
1579   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1580   Vals.clear();
1581
1582   // If there are function-local constants, emit them now.
1583   unsigned CstStart, CstEnd;
1584   VE.getFunctionConstantRange(CstStart, CstEnd);
1585   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1586
1587   // If there is function-local metadata, emit it now.
1588   WriteFunctionLocalMetadata(F, VE, Stream);
1589
1590   // Keep a running idea of what the instruction ID is.
1591   unsigned InstID = CstEnd;
1592
1593   bool NeedsMetadataAttachment = false;
1594
1595   DebugLoc LastDL;
1596
1597   // Finally, emit all the instructions, in order.
1598   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1599     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1600          I != E; ++I) {
1601       WriteInstruction(*I, InstID, VE, Stream, Vals);
1602
1603       if (!I->getType()->isVoidTy())
1604         ++InstID;
1605
1606       // If the instruction has metadata, write a metadata attachment later.
1607       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1608
1609       // If the instruction has a debug location, emit it.
1610       DebugLoc DL = I->getDebugLoc();
1611       if (DL.isUnknown()) {
1612         // nothing todo.
1613       } else if (DL == LastDL) {
1614         // Just repeat the same debug loc as last time.
1615         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1616       } else {
1617         MDNode *Scope, *IA;
1618         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1619
1620         Vals.push_back(DL.getLine());
1621         Vals.push_back(DL.getCol());
1622         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1623         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1624         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1625         Vals.clear();
1626
1627         LastDL = DL;
1628       }
1629     }
1630
1631   // Emit names for all the instructions etc.
1632   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1633
1634   if (NeedsMetadataAttachment)
1635     WriteMetadataAttachment(F, VE, Stream);
1636   VE.purgeFunction();
1637   Stream.ExitBlock();
1638 }
1639
1640 // Emit blockinfo, which defines the standard abbreviations etc.
1641 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1642   // We only want to emit block info records for blocks that have multiple
1643   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1644   // Other blocks can define their abbrevs inline.
1645   Stream.EnterBlockInfoBlock(2);
1646
1647   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1648     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1649     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1650     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1652     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1653     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1654                                    Abbv) != VST_ENTRY_8_ABBREV)
1655       llvm_unreachable("Unexpected abbrev ordering!");
1656   }
1657
1658   { // 7-bit fixed width VST_ENTRY strings.
1659     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1660     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1661     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1664     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1665                                    Abbv) != VST_ENTRY_7_ABBREV)
1666       llvm_unreachable("Unexpected abbrev ordering!");
1667   }
1668   { // 6-bit char6 VST_ENTRY strings.
1669     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1670     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1673     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1674     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1675                                    Abbv) != VST_ENTRY_6_ABBREV)
1676       llvm_unreachable("Unexpected abbrev ordering!");
1677   }
1678   { // 6-bit char6 VST_BBENTRY strings.
1679     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1680     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1682     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1683     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1684     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1685                                    Abbv) != VST_BBENTRY_6_ABBREV)
1686       llvm_unreachable("Unexpected abbrev ordering!");
1687   }
1688
1689
1690
1691   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1692     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1693     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1694     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1695                               Log2_32_Ceil(VE.getTypes().size()+1)));
1696     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1697                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1698       llvm_unreachable("Unexpected abbrev ordering!");
1699   }
1700
1701   { // INTEGER abbrev for CONSTANTS_BLOCK.
1702     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1703     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1704     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1705     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1706                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1707       llvm_unreachable("Unexpected abbrev ordering!");
1708   }
1709
1710   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1711     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1712     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1713     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1714     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1715                               Log2_32_Ceil(VE.getTypes().size()+1)));
1716     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1717
1718     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1719                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1720       llvm_unreachable("Unexpected abbrev ordering!");
1721   }
1722   { // NULL abbrev for CONSTANTS_BLOCK.
1723     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1724     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1725     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1726                                    Abbv) != CONSTANTS_NULL_Abbrev)
1727       llvm_unreachable("Unexpected abbrev ordering!");
1728   }
1729
1730   // FIXME: This should only use space for first class types!
1731
1732   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1733     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1734     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1735     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1736     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1737     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1738     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1739                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1740       llvm_unreachable("Unexpected abbrev ordering!");
1741   }
1742   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1743     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1744     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1745     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1746     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1747     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1748     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1749                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1750       llvm_unreachable("Unexpected abbrev ordering!");
1751   }
1752   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1753     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1754     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1755     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1756     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1757     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1758     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1759     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1760                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1761       llvm_unreachable("Unexpected abbrev ordering!");
1762   }
1763   { // INST_CAST abbrev for FUNCTION_BLOCK.
1764     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1765     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1766     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1767     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1768                               Log2_32_Ceil(VE.getTypes().size()+1)));
1769     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1770     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1771                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1772       llvm_unreachable("Unexpected abbrev ordering!");
1773   }
1774
1775   { // INST_RET abbrev for FUNCTION_BLOCK.
1776     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1777     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1778     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1779                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1780       llvm_unreachable("Unexpected abbrev ordering!");
1781   }
1782   { // INST_RET abbrev for FUNCTION_BLOCK.
1783     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1784     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1786     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1787                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1788       llvm_unreachable("Unexpected abbrev ordering!");
1789   }
1790   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1791     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1792     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1793     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1794                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1795       llvm_unreachable("Unexpected abbrev ordering!");
1796   }
1797
1798   Stream.ExitBlock();
1799 }
1800
1801 // Sort the Users based on the order in which the reader parses the bitcode
1802 // file.
1803 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1804   // TODO: Implement.
1805   return true;
1806 }
1807
1808 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1809                          BitstreamWriter &Stream) {
1810
1811   // One or zero uses can't get out of order.
1812   if (V->use_empty() || V->hasNUses(1))
1813     return;
1814
1815   // Make a copy of the in-memory use-list for sorting.
1816   SmallVector<const User*, 8> UserList(V->user_begin(), V->user_end());
1817
1818   // Sort the copy based on the order read by the BitcodeReader.
1819   std::sort(UserList.begin(), UserList.end(), bitcodereader_order);
1820
1821   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1822   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1823
1824   // TODO: Emit the USELIST_CODE_ENTRYs.
1825 }
1826
1827 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1828                                  BitstreamWriter &Stream) {
1829   VE.incorporateFunction(*F);
1830
1831   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1832        AI != AE; ++AI)
1833     WriteUseList(AI, VE, Stream);
1834   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1835        ++BB) {
1836     WriteUseList(BB, VE, Stream);
1837     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1838          ++II) {
1839       WriteUseList(II, VE, Stream);
1840       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1841            OI != E; ++OI) {
1842         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1843             isa<InlineAsm>(*OI))
1844           WriteUseList(*OI, VE, Stream);
1845       }
1846     }
1847   }
1848   VE.purgeFunction();
1849 }
1850
1851 // Emit use-lists.
1852 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1853                                 BitstreamWriter &Stream) {
1854   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1855
1856   // XXX: this modifies the module, but in a way that should never change the
1857   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1858   // contain entries in the use_list that do not exist in the Module and are
1859   // not stored in the .bc file.
1860   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1861        I != E; ++I)
1862     I->removeDeadConstantUsers();
1863
1864   // Write the global variables.
1865   for (Module::const_global_iterator GI = M->global_begin(),
1866          GE = M->global_end(); GI != GE; ++GI) {
1867     WriteUseList(GI, VE, Stream);
1868
1869     // Write the global variable initializers.
1870     if (GI->hasInitializer())
1871       WriteUseList(GI->getInitializer(), VE, Stream);
1872   }
1873
1874   // Write the functions.
1875   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1876     WriteUseList(FI, VE, Stream);
1877     if (!FI->isDeclaration())
1878       WriteFunctionUseList(FI, VE, Stream);
1879     if (FI->hasPrefixData())
1880       WriteUseList(FI->getPrefixData(), VE, Stream);
1881   }
1882
1883   // Write the aliases.
1884   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1885        AI != AE; ++AI) {
1886     WriteUseList(AI, VE, Stream);
1887     WriteUseList(AI->getAliasee(), VE, Stream);
1888   }
1889
1890   Stream.ExitBlock();
1891 }
1892
1893 /// WriteModule - Emit the specified module to the bitstream.
1894 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1895   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1896
1897   SmallVector<unsigned, 1> Vals;
1898   unsigned CurVersion = 1;
1899   Vals.push_back(CurVersion);
1900   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1901
1902   // Analyze the module, enumerating globals, functions, etc.
1903   ValueEnumerator VE(M);
1904
1905   // Emit blockinfo, which defines the standard abbreviations etc.
1906   WriteBlockInfo(VE, Stream);
1907
1908   // Emit information about attribute groups.
1909   WriteAttributeGroupTable(VE, Stream);
1910
1911   // Emit information about parameter attributes.
1912   WriteAttributeTable(VE, Stream);
1913
1914   // Emit information describing all of the types in the module.
1915   WriteTypeTable(VE, Stream);
1916
1917   // Emit top-level description of module, including target triple, inline asm,
1918   // descriptors for global variables, and function prototype info.
1919   WriteModuleInfo(M, VE, Stream);
1920
1921   // Emit constants.
1922   WriteModuleConstants(VE, Stream);
1923
1924   // Emit metadata.
1925   WriteModuleMetadata(M, VE, Stream);
1926
1927   // Emit metadata.
1928   WriteModuleMetadataStore(M, Stream);
1929
1930   // Emit names for globals/functions etc.
1931   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1932
1933   // Emit use-lists.
1934   if (EnablePreserveUseListOrdering)
1935     WriteModuleUseLists(M, VE, Stream);
1936
1937   // Emit function bodies.
1938   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1939     if (!F->isDeclaration())
1940       WriteFunction(*F, VE, Stream);
1941
1942   Stream.ExitBlock();
1943 }
1944
1945 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1946 /// header and trailer to make it compatible with the system archiver.  To do
1947 /// this we emit the following header, and then emit a trailer that pads the
1948 /// file out to be a multiple of 16 bytes.
1949 ///
1950 /// struct bc_header {
1951 ///   uint32_t Magic;         // 0x0B17C0DE
1952 ///   uint32_t Version;       // Version, currently always 0.
1953 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1954 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1955 ///   uint32_t CPUType;       // CPU specifier.
1956 ///   ... potentially more later ...
1957 /// };
1958 enum {
1959   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1960   DarwinBCHeaderSize = 5*4
1961 };
1962
1963 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1964                                uint32_t &Position) {
1965   Buffer[Position + 0] = (unsigned char) (Value >>  0);
1966   Buffer[Position + 1] = (unsigned char) (Value >>  8);
1967   Buffer[Position + 2] = (unsigned char) (Value >> 16);
1968   Buffer[Position + 3] = (unsigned char) (Value >> 24);
1969   Position += 4;
1970 }
1971
1972 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1973                                          const Triple &TT) {
1974   unsigned CPUType = ~0U;
1975
1976   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1977   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1978   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1979   // specific constants here because they are implicitly part of the Darwin ABI.
1980   enum {
1981     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1982     DARWIN_CPU_TYPE_X86        = 7,
1983     DARWIN_CPU_TYPE_ARM        = 12,
1984     DARWIN_CPU_TYPE_POWERPC    = 18
1985   };
1986
1987   Triple::ArchType Arch = TT.getArch();
1988   if (Arch == Triple::x86_64)
1989     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1990   else if (Arch == Triple::x86)
1991     CPUType = DARWIN_CPU_TYPE_X86;
1992   else if (Arch == Triple::ppc)
1993     CPUType = DARWIN_CPU_TYPE_POWERPC;
1994   else if (Arch == Triple::ppc64)
1995     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1996   else if (Arch == Triple::arm || Arch == Triple::thumb)
1997     CPUType = DARWIN_CPU_TYPE_ARM;
1998
1999   // Traditional Bitcode starts after header.
2000   assert(Buffer.size() >= DarwinBCHeaderSize &&
2001          "Expected header size to be reserved");
2002   unsigned BCOffset = DarwinBCHeaderSize;
2003   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2004
2005   // Write the magic and version.
2006   unsigned Position = 0;
2007   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2008   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2009   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2010   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2011   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2012
2013   // If the file is not a multiple of 16 bytes, insert dummy padding.
2014   while (Buffer.size() & 15)
2015     Buffer.push_back(0);
2016 }
2017
2018 /// WriteBitcodeToFile - Write the specified module to the specified output
2019 /// stream.
2020 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2021   SmallVector<char, 0> Buffer;
2022   Buffer.reserve(256*1024);
2023
2024   // If this is darwin or another generic macho target, reserve space for the
2025   // header.
2026   Triple TT(M->getTargetTriple());
2027   if (TT.isOSDarwin())
2028     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2029
2030   // Emit the module into the buffer.
2031   {
2032     BitstreamWriter Stream(Buffer);
2033
2034     // Emit the file header.
2035     Stream.Emit((unsigned)'B', 8);
2036     Stream.Emit((unsigned)'C', 8);
2037     Stream.Emit(0x0, 4);
2038     Stream.Emit(0xC, 4);
2039     Stream.Emit(0xE, 4);
2040     Stream.Emit(0xD, 4);
2041
2042     // Emit the module.
2043     WriteModule(M, Stream);
2044   }
2045
2046   if (TT.isOSDarwin())
2047     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2048
2049   // Write the generated bitstream to "Out".
2050   Out.write((char*)&Buffer.front(), Buffer.size());
2051 }