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   }
 491   llvm_unreachable("Invalid linkage");
 492 }
 493
 494 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 495   switch (GV->getVisibility()) {
 496   case GlobalValue::DefaultVisibility:   return 0;
 497   case GlobalValue::HiddenVisibility:    return 1;
 498   case GlobalValue::ProtectedVisibility: return 2;
 499   }
 500   llvm_unreachable("Invalid visibility");
 501 }
 502
 503 static unsigned getEncodedDLLStorageClass(const GlobalValue *GV) {
 504   switch (GV->getDLLStorageClass()) {
 505   case GlobalValue::DefaultStorageClass:   return 0;
 506   case GlobalValue::DLLImportStorageClass: return 1;
 507   case GlobalValue::DLLExportStorageClass: return 2;
 508   }
 509   llvm_unreachable("Invalid DLL storage class");
 510 }
 511
 512 static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
 513   switch (GV->getThreadLocalMode()) {
 514     case GlobalVariable::NotThreadLocal:         return 0;
 515     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 516     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 517     case GlobalVariable::InitialExecTLSModel:    return 3;
 518     case GlobalVariable::LocalExecTLSModel:      return 4;
 519   }
 520   llvm_unreachable("Invalid TLS model");
 521 }
 522
 523 // Emit top-level description of module, including target triple, inline asm,
 524 // descriptors for global variables, and function prototype info.
 525 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 526                             BitstreamWriter &Stream) {
 527   // Emit various pieces of data attached to a module.
 528   if (!M->getTargetTriple().empty())
 529     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 530                       0/*TODO*/, Stream);
 531   const std::string &DL = M->getDataLayoutStr();
 532   if (!DL.empty())
 533     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 534   if (!M->getModuleInlineAsm().empty())
 535     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 536                       0/*TODO*/, Stream);
 537
 538   // Emit information about sections and GC, computing how many there are. Also
 539   // compute the maximum alignment value.
 540   std::map<std::string, unsigned> SectionMap;
 541   std::map<std::string, unsigned> GCMap;
 542   unsigned MaxAlignment = 0;
 543   unsigned MaxGlobalType = 0;
 544   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 545        GV != E; ++GV) {
 546     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 547     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 548     if (GV->hasSection()) {
 549       // Give section names unique ID's.
 550       unsigned &Entry = SectionMap[GV->getSection()];
 551       if (!Entry) {
 552         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 553                           0/*TODO*/, Stream);
 554         Entry = SectionMap.size();
 555       }
 556     }
 557   }
 558   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 559     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 560     if (F->hasSection()) {
 561       // Give section names unique ID's.
 562       unsigned &Entry = SectionMap[F->getSection()];
 563       if (!Entry) {
 564         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 565                           0/*TODO*/, Stream);
 566         Entry = SectionMap.size();
 567       }
 568     }
 569     if (F->hasGC()) {
 570       // Same for GC names.
 571       unsigned &Entry = GCMap[F->getGC()];
 572       if (!Entry) {
 573         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 574                           0/*TODO*/, Stream);
 575         Entry = GCMap.size();
 576       }
 577     }
 578   }
 579
 580   // Emit abbrev for globals, now that we know # sections and max alignment.
 581   unsigned SimpleGVarAbbrev = 0;
 582   if (!M->global_empty()) {
 583     // Add an abbrev for common globals with no visibility or thread localness.
 584     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 585     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 586     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 587                               Log2_32_Ceil(MaxGlobalType+1)));
 588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 591     if (MaxAlignment == 0)                                      // Alignment.
 592       Abbv->Add(BitCodeAbbrevOp(0));
 593     else {
 594       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 595       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 596                                Log2_32_Ceil(MaxEncAlignment+1)));
 597     }
 598     if (SectionMap.empty())                                    // Section.
 599       Abbv->Add(BitCodeAbbrevOp(0));
 600     else
 601       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 602                                Log2_32_Ceil(SectionMap.size()+1)));
 603     // Don't bother emitting vis + thread local.
 604     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 605   }
 606
 607   // Emit the global variable information.
 608   SmallVector<unsigned, 64> Vals;
 609   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 610        GV != E; ++GV) {
 611     unsigned AbbrevToUse = 0;
 612
 613     // GLOBALVAR: [type, isconst, initid,
 614     //             linkage, alignment, section, visibility, threadlocal,
 615     //             unnamed_addr, externally_initialized, dllstorageclass]
 616     Vals.push_back(VE.getTypeID(GV->getType()));
 617     Vals.push_back(GV->isConstant());
 618     Vals.push_back(GV->isDeclaration() ? 0 :
 619                    (VE.getValueID(GV->getInitializer()) + 1));
 620     Vals.push_back(getEncodedLinkage(GV));
 621     Vals.push_back(Log2_32(GV->getAlignment())+1);
 622     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 623     if (GV->isThreadLocal() ||
 624         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 625         GV->hasUnnamedAddr() || GV->isExternallyInitialized() ||
 626         GV->getDLLStorageClass() != GlobalValue::DefaultStorageClass) {
 627       Vals.push_back(getEncodedVisibility(GV));
 628       Vals.push_back(getEncodedThreadLocalMode(GV));
 629       Vals.push_back(GV->hasUnnamedAddr());
 630       Vals.push_back(GV->isExternallyInitialized());
 631       Vals.push_back(getEncodedDLLStorageClass(GV));
 632     } else {
 633       AbbrevToUse = SimpleGVarAbbrev;
 634     }
 635
 636     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 637     Vals.clear();
 638   }
 639
 640   // Emit the function proto information.
 641   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 642     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 643     //             section, visibility, gc, unnamed_addr, prefix]
 644     Vals.push_back(VE.getTypeID(F->getType()));
 645     Vals.push_back(F->getCallingConv());
 646     Vals.push_back(F->isDeclaration());
 647     Vals.push_back(getEncodedLinkage(F));
 648     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 649     Vals.push_back(Log2_32(F->getAlignment())+1);
 650     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 651     Vals.push_back(getEncodedVisibility(F));
 652     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 653     Vals.push_back(F->hasUnnamedAddr());
 654     Vals.push_back(F->hasPrefixData() ? (VE.getValueID(F->getPrefixData()) + 1)
 655                                       : 0);
 656     Vals.push_back(getEncodedDLLStorageClass(F));
 657
 658     unsigned AbbrevToUse = 0;
 659     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 660     Vals.clear();
 661   }
 662
 663   // Emit the alias information.
 664   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 665        AI != E; ++AI) {
 666     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 667     Vals.push_back(VE.getTypeID(AI->getType()));
 668     Vals.push_back(VE.getValueID(AI->getAliasee()));
 669     Vals.push_back(getEncodedLinkage(AI));
 670     Vals.push_back(getEncodedVisibility(AI));
 671     Vals.push_back(getEncodedDLLStorageClass(AI));
 672     unsigned AbbrevToUse = 0;
 673     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 674     Vals.clear();
 675   }
 676 }
 677
 678 static uint64_t GetOptimizationFlags(const Value *V) {
 679   uint64_t Flags = 0;
 680
 681   if (const OverflowingBinaryOperator *OBO =
 682         dyn_cast<OverflowingBinaryOperator>(V)) {
 683     if (OBO->hasNoSignedWrap())
 684       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 685     if (OBO->hasNoUnsignedWrap())
 686       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 687   } else if (const PossiblyExactOperator *PEO =
 688                dyn_cast<PossiblyExactOperator>(V)) {
 689     if (PEO->isExact())
 690       Flags |= 1 << bitc::PEO_EXACT;
 691   } else if (const FPMathOperator *FPMO =
 692              dyn_cast<const FPMathOperator>(V)) {
 693     if (FPMO->hasUnsafeAlgebra())
 694       Flags |= FastMathFlags::UnsafeAlgebra;
 695     if (FPMO->hasNoNaNs())
 696       Flags |= FastMathFlags::NoNaNs;
 697     if (FPMO->hasNoInfs())
 698       Flags |= FastMathFlags::NoInfs;
 699     if (FPMO->hasNoSignedZeros())
 700       Flags |= FastMathFlags::NoSignedZeros;
 701     if (FPMO->hasAllowReciprocal())
 702       Flags |= FastMathFlags::AllowReciprocal;
 703   }
 704
 705   return Flags;
 706 }
 707
 708 static void WriteMDNode(const MDNode *N,
 709                         const ValueEnumerator &VE,
 710                         BitstreamWriter &Stream,
 711                         SmallVectorImpl<uint64_t> &Record) {
 712   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 713     if (N->getOperand(i)) {
 714       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 715       Record.push_back(VE.getValueID(N->getOperand(i)));
 716     } else {
 717       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 718       Record.push_back(0);
 719     }
 720   }
 721   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 722                                            bitc::METADATA_NODE;
 723   Stream.EmitRecord(MDCode, Record, 0);
 724   Record.clear();
 725 }
 726
 727 static void WriteModuleMetadata(const Module *M,
 728                                 const ValueEnumerator &VE,
 729                                 BitstreamWriter &Stream) {
 730   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 731   bool StartedMetadataBlock = false;
 732   unsigned MDSAbbrev = 0;
 733   SmallVector<uint64_t, 64> Record;
 734   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 735
 736     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 737       if (!N->isFunctionLocal() || !N->getFunction()) {
 738         if (!StartedMetadataBlock) {
 739           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 740           StartedMetadataBlock = true;
 741         }
 742         WriteMDNode(N, VE, Stream, Record);
 743       }
 744     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 745       if (!StartedMetadataBlock)  {
 746         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 747
 748         // Abbrev for METADATA_STRING.
 749         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 750         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 751         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 752         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 753         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 754         StartedMetadataBlock = true;
 755       }
 756
 757       // Code: [strchar x N]
 758       Record.append(MDS->begin(), MDS->end());
 759
 760       // Emit the finished record.
 761       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 762       Record.clear();
 763     }
 764   }
 765
 766   // Write named metadata.
 767   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 768        E = M->named_metadata_end(); I != E; ++I) {
 769     const NamedMDNode *NMD = I;
 770     if (!StartedMetadataBlock)  {
 771       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 772       StartedMetadataBlock = true;
 773     }
 774
 775     // Write name.
 776     StringRef Str = NMD->getName();
 777     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 778       Record.push_back(Str[i]);
 779     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 780     Record.clear();
 781
 782     // Write named metadata operands.
 783     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 784       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 785     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 786     Record.clear();
 787   }
 788
 789   if (StartedMetadataBlock)
 790     Stream.ExitBlock();
 791 }
 792
 793 static void WriteFunctionLocalMetadata(const Function &F,
 794                                        const ValueEnumerator &VE,
 795                                        BitstreamWriter &Stream) {
 796   bool StartedMetadataBlock = false;
 797   SmallVector<uint64_t, 64> Record;
 798   const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
 799   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 800     if (const MDNode *N = Vals[i])
 801       if (N->isFunctionLocal() && N->getFunction() == &F) {
 802         if (!StartedMetadataBlock) {
 803           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 804           StartedMetadataBlock = true;
 805         }
 806         WriteMDNode(N, VE, Stream, Record);
 807       }
 808
 809   if (StartedMetadataBlock)
 810     Stream.ExitBlock();
 811 }
 812
 813 static void WriteMetadataAttachment(const Function &F,
 814                                     const ValueEnumerator &VE,
 815                                     BitstreamWriter &Stream) {
 816   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 817
 818   SmallVector<uint64_t, 64> Record;
 819
 820   // Write metadata attachments
 821   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 822   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 823
 824   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 825     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 826          I != E; ++I) {
 827       MDs.clear();
 828       I->getAllMetadataOtherThanDebugLoc(MDs);
 829
 830       // If no metadata, ignore instruction.
 831       if (MDs.empty()) continue;
 832
 833       Record.push_back(VE.getInstructionID(I));
 834
 835       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 836         Record.push_back(MDs[i].first);
 837         Record.push_back(VE.getValueID(MDs[i].second));
 838       }
 839       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 840       Record.clear();
 841     }
 842
 843   Stream.ExitBlock();
 844 }
 845
 846 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 847   SmallVector<uint64_t, 64> Record;
 848
 849   // Write metadata kinds
 850   // METADATA_KIND - [n x [id, name]]
 851   SmallVector<StringRef, 8> Names;
 852   M->getMDKindNames(Names);
 853
 854   if (Names.empty()) return;
 855
 856   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 857
 858   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 859     Record.push_back(MDKindID);
 860     StringRef KName = Names[MDKindID];
 861     Record.append(KName.begin(), KName.end());
 862
 863     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 864     Record.clear();
 865   }
 866
 867   Stream.ExitBlock();
 868 }
 869
 870 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 871   if ((int64_t)V >= 0)
 872     Vals.push_back(V << 1);
 873   else
 874     Vals.push_back((-V << 1) | 1);
 875 }
 876
 877 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 878                            const ValueEnumerator &VE,
 879                            BitstreamWriter &Stream, bool isGlobal) {
 880   if (FirstVal == LastVal) return;
 881
 882   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 883
 884   unsigned AggregateAbbrev = 0;
 885   unsigned String8Abbrev = 0;
 886   unsigned CString7Abbrev = 0;
 887   unsigned CString6Abbrev = 0;
 888   // If this is a constant pool for the module, emit module-specific abbrevs.
 889   if (isGlobal) {
 890     // Abbrev for CST_CODE_AGGREGATE.
 891     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 892     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 895     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 896
 897     // Abbrev for CST_CODE_STRING.
 898     Abbv = new BitCodeAbbrev();
 899     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 900     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 901     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 902     String8Abbrev = Stream.EmitAbbrev(Abbv);
 903     // Abbrev for CST_CODE_CSTRING.
 904     Abbv = new BitCodeAbbrev();
 905     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 906     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 907     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 908     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 909     // Abbrev for CST_CODE_CSTRING.
 910     Abbv = new BitCodeAbbrev();
 911     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 912     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 913     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 914     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 915   }
 916
 917   SmallVector<uint64_t, 64> Record;
 918
 919   const ValueEnumerator::ValueList &Vals = VE.getValues();
 920   Type *LastTy = 0;
 921   for (unsigned i = FirstVal; i != LastVal; ++i) {
 922     const Value *V = Vals[i].first;
 923     // If we need to switch types, do so now.
 924     if (V->getType() != LastTy) {
 925       LastTy = V->getType();
 926       Record.push_back(VE.getTypeID(LastTy));
 927       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 928                         CONSTANTS_SETTYPE_ABBREV);
 929       Record.clear();
 930     }
 931
 932     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 933       Record.push_back(unsigned(IA->hasSideEffects()) |
 934                        unsigned(IA->isAlignStack()) << 1 |
 935                        unsigned(IA->getDialect()&1) << 2);
 936
 937       // Add the asm string.
 938       const std::string &AsmStr = IA->getAsmString();
 939       Record.push_back(AsmStr.size());
 940       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 941         Record.push_back(AsmStr[i]);
 942
 943       // Add the constraint string.
 944       const std::string &ConstraintStr = IA->getConstraintString();
 945       Record.push_back(ConstraintStr.size());
 946       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 947         Record.push_back(ConstraintStr[i]);
 948       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 949       Record.clear();
 950       continue;
 951     }
 952     const Constant *C = cast<Constant>(V);
 953     unsigned Code = -1U;
 954     unsigned AbbrevToUse = 0;
 955     if (C->isNullValue()) {
 956       Code = bitc::CST_CODE_NULL;
 957     } else if (isa<UndefValue>(C)) {
 958       Code = bitc::CST_CODE_UNDEF;
 959     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 960       if (IV->getBitWidth() <= 64) {
 961         uint64_t V = IV->getSExtValue();
 962         emitSignedInt64(Record, V);
 963         Code = bitc::CST_CODE_INTEGER;
 964         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 965       } else {                             // Wide integers, > 64 bits in size.
 966         // We have an arbitrary precision integer value to write whose
 967         // bit width is > 64. However, in canonical unsigned integer
 968         // format it is likely that the high bits are going to be zero.
 969         // So, we only write the number of active words.
 970         unsigned NWords = IV->getValue().getActiveWords();
 971         const uint64_t *RawWords = IV->getValue().getRawData();
 972         for (unsigned i = 0; i != NWords; ++i) {
 973           emitSignedInt64(Record, RawWords[i]);
 974         }
 975         Code = bitc::CST_CODE_WIDE_INTEGER;
 976       }
 977     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 978       Code = bitc::CST_CODE_FLOAT;
 979       Type *Ty = CFP->getType();
 980       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
 981         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 982       } else if (Ty->isX86_FP80Ty()) {
 983         // api needed to prevent premature destruction
 984         // bits are not in the same order as a normal i80 APInt, compensate.
 985         APInt api = CFP->getValueAPF().bitcastToAPInt();
 986         const uint64_t *p = api.getRawData();
 987         Record.push_back((p[1] << 48) | (p[0] >> 16));
 988         Record.push_back(p[0] & 0xffffLL);
 989       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 990         APInt api = CFP->getValueAPF().bitcastToAPInt();
 991         const uint64_t *p = api.getRawData();
 992         Record.push_back(p[0]);
 993         Record.push_back(p[1]);
 994       } else {
 995         assert (0 && "Unknown FP type!");
 996       }
 997     } else if (isa<ConstantDataSequential>(C) &&
 998                cast<ConstantDataSequential>(C)->isString()) {
 999       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1000       // Emit constant strings specially.
1001       unsigned NumElts = Str->getNumElements();
1002       // If this is a null-terminated string, use the denser CSTRING encoding.
1003       if (Str->isCString()) {
1004         Code = bitc::CST_CODE_CSTRING;
1005         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1006       } else {
1007         Code = bitc::CST_CODE_STRING;
1008         AbbrevToUse = String8Abbrev;
1009       }
1010       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1011       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1012       for (unsigned i = 0; i != NumElts; ++i) {
1013         unsigned char V = Str->getElementAsInteger(i);
1014         Record.push_back(V);
1015         isCStr7 &= (V & 128) == 0;
1016         if (isCStrChar6)
1017           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1018       }
1019
1020       if (isCStrChar6)
1021         AbbrevToUse = CString6Abbrev;
1022       else if (isCStr7)
1023         AbbrevToUse = CString7Abbrev;
1024     } else if (const ConstantDataSequential *CDS =
1025                   dyn_cast<ConstantDataSequential>(C)) {
1026       Code = bitc::CST_CODE_DATA;
1027       Type *EltTy = CDS->getType()->getElementType();
1028       if (isa<IntegerType>(EltTy)) {
1029         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1030           Record.push_back(CDS->getElementAsInteger(i));
1031       } else if (EltTy->isFloatTy()) {
1032         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1033           union { float F; uint32_t I; };
1034           F = CDS->getElementAsFloat(i);
1035           Record.push_back(I);
1036         }
1037       } else {
1038         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1039         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1040           union { double F; uint64_t I; };
1041           F = CDS->getElementAsDouble(i);
1042           Record.push_back(I);
1043         }
1044       }
1045     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1046                isa<ConstantVector>(C)) {
1047       Code = bitc::CST_CODE_AGGREGATE;
1048       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1049         Record.push_back(VE.getValueID(C->getOperand(i)));
1050       AbbrevToUse = AggregateAbbrev;
1051     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1052       switch (CE->getOpcode()) {
1053       default:
1054         if (Instruction::isCast(CE->getOpcode())) {
1055           Code = bitc::CST_CODE_CE_CAST;
1056           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1057           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1058           Record.push_back(VE.getValueID(C->getOperand(0)));
1059           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1060         } else {
1061           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1062           Code = bitc::CST_CODE_CE_BINOP;
1063           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1064           Record.push_back(VE.getValueID(C->getOperand(0)));
1065           Record.push_back(VE.getValueID(C->getOperand(1)));
1066           uint64_t Flags = GetOptimizationFlags(CE);
1067           if (Flags != 0)
1068             Record.push_back(Flags);
1069         }
1070         break;
1071       case Instruction::GetElementPtr:
1072         Code = bitc::CST_CODE_CE_GEP;
1073         if (cast<GEPOperator>(C)->isInBounds())
1074           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1075         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1076           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1077           Record.push_back(VE.getValueID(C->getOperand(i)));
1078         }
1079         break;
1080       case Instruction::Select:
1081         Code = bitc::CST_CODE_CE_SELECT;
1082         Record.push_back(VE.getValueID(C->getOperand(0)));
1083         Record.push_back(VE.getValueID(C->getOperand(1)));
1084         Record.push_back(VE.getValueID(C->getOperand(2)));
1085         break;
1086       case Instruction::ExtractElement:
1087         Code = bitc::CST_CODE_CE_EXTRACTELT;
1088         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1089         Record.push_back(VE.getValueID(C->getOperand(0)));
1090         Record.push_back(VE.getValueID(C->getOperand(1)));
1091         break;
1092       case Instruction::InsertElement:
1093         Code = bitc::CST_CODE_CE_INSERTELT;
1094         Record.push_back(VE.getValueID(C->getOperand(0)));
1095         Record.push_back(VE.getValueID(C->getOperand(1)));
1096         Record.push_back(VE.getValueID(C->getOperand(2)));
1097         break;
1098       case Instruction::ShuffleVector:
1099         // If the return type and argument types are the same, this is a
1100         // standard shufflevector instruction.  If the types are different,
1101         // then the shuffle is widening or truncating the input vectors, and
1102         // the argument type must also be encoded.
1103         if (C->getType() == C->getOperand(0)->getType()) {
1104           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1105         } else {
1106           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1107           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1108         }
1109         Record.push_back(VE.getValueID(C->getOperand(0)));
1110         Record.push_back(VE.getValueID(C->getOperand(1)));
1111         Record.push_back(VE.getValueID(C->getOperand(2)));
1112         break;
1113       case Instruction::ICmp:
1114       case Instruction::FCmp:
1115         Code = bitc::CST_CODE_CE_CMP;
1116         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1117         Record.push_back(VE.getValueID(C->getOperand(0)));
1118         Record.push_back(VE.getValueID(C->getOperand(1)));
1119         Record.push_back(CE->getPredicate());
1120         break;
1121       }
1122     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1123       Code = bitc::CST_CODE_BLOCKADDRESS;
1124       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1125       Record.push_back(VE.getValueID(BA->getFunction()));
1126       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1127     } else {
1128 #ifndef NDEBUG
1129       C->dump();
1130 #endif
1131       llvm_unreachable("Unknown constant!");
1132     }
1133     Stream.EmitRecord(Code, Record, AbbrevToUse);
1134     Record.clear();
1135   }
1136
1137   Stream.ExitBlock();
1138 }
1139
1140 static void WriteModuleConstants(const ValueEnumerator &VE,
1141                                  BitstreamWriter &Stream) {
1142   const ValueEnumerator::ValueList &Vals = VE.getValues();
1143
1144   // Find the first constant to emit, which is the first non-globalvalue value.
1145   // We know globalvalues have been emitted by WriteModuleInfo.
1146   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1147     if (!isa<GlobalValue>(Vals[i].first)) {
1148       WriteConstants(i, Vals.size(), VE, Stream, true);
1149       return;
1150     }
1151   }
1152 }
1153
1154 /// PushValueAndType - The file has to encode both the value and type id for
1155 /// many values, because we need to know what type to create for forward
1156 /// references.  However, most operands are not forward references, so this type
1157 /// field is not needed.
1158 ///
1159 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1160 /// instruction ID, then it is a forward reference, and it also includes the
1161 /// type ID.  The value ID that is written is encoded relative to the InstID.
1162 static bool PushValueAndType(const Value *V, unsigned InstID,
1163                              SmallVectorImpl<unsigned> &Vals,
1164                              ValueEnumerator &VE) {
1165   unsigned ValID = VE.getValueID(V);
1166   // Make encoding relative to the InstID.
1167   Vals.push_back(InstID - ValID);
1168   if (ValID >= InstID) {
1169     Vals.push_back(VE.getTypeID(V->getType()));
1170     return true;
1171   }
1172   return false;
1173 }
1174
1175 /// pushValue - Like PushValueAndType, but where the type of the value is
1176 /// omitted (perhaps it was already encoded in an earlier operand).
1177 static void pushValue(const Value *V, unsigned InstID,
1178                       SmallVectorImpl<unsigned> &Vals,
1179                       ValueEnumerator &VE) {
1180   unsigned ValID = VE.getValueID(V);
1181   Vals.push_back(InstID - ValID);
1182 }
1183
1184 static void pushValueSigned(const Value *V, unsigned InstID,
1185                             SmallVectorImpl<uint64_t> &Vals,
1186                             ValueEnumerator &VE) {
1187   unsigned ValID = VE.getValueID(V);
1188   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1189   emitSignedInt64(Vals, diff);
1190 }
1191
1192 /// WriteInstruction - Emit an instruction to the specified stream.
1193 static void WriteInstruction(const Instruction &I, unsigned InstID,
1194                              ValueEnumerator &VE, BitstreamWriter &Stream,
1195                              SmallVectorImpl<unsigned> &Vals) {
1196   unsigned Code = 0;
1197   unsigned AbbrevToUse = 0;
1198   VE.setInstructionID(&I);
1199   switch (I.getOpcode()) {
1200   default:
1201     if (Instruction::isCast(I.getOpcode())) {
1202       Code = bitc::FUNC_CODE_INST_CAST;
1203       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1204         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1205       Vals.push_back(VE.getTypeID(I.getType()));
1206       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1207     } else {
1208       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1209       Code = bitc::FUNC_CODE_INST_BINOP;
1210       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1211         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1212       pushValue(I.getOperand(1), InstID, Vals, VE);
1213       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1214       uint64_t Flags = GetOptimizationFlags(&I);
1215       if (Flags != 0) {
1216         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1217           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1218         Vals.push_back(Flags);
1219       }
1220     }
1221     break;
1222
1223   case Instruction::GetElementPtr:
1224     Code = bitc::FUNC_CODE_INST_GEP;
1225     if (cast<GEPOperator>(&I)->isInBounds())
1226       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1227     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1228       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1229     break;
1230   case Instruction::ExtractValue: {
1231     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1232     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1233     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1234     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1235       Vals.push_back(*i);
1236     break;
1237   }
1238   case Instruction::InsertValue: {
1239     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1240     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1241     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1242     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1243     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1244       Vals.push_back(*i);
1245     break;
1246   }
1247   case Instruction::Select:
1248     Code = bitc::FUNC_CODE_INST_VSELECT;
1249     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1250     pushValue(I.getOperand(2), InstID, Vals, VE);
1251     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1252     break;
1253   case Instruction::ExtractElement:
1254     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1255     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1256     pushValue(I.getOperand(1), InstID, Vals, VE);
1257     break;
1258   case Instruction::InsertElement:
1259     Code = bitc::FUNC_CODE_INST_INSERTELT;
1260     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1261     pushValue(I.getOperand(1), InstID, Vals, VE);
1262     pushValue(I.getOperand(2), InstID, Vals, VE);
1263     break;
1264   case Instruction::ShuffleVector:
1265     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1266     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1267     pushValue(I.getOperand(1), InstID, Vals, VE);
1268     pushValue(I.getOperand(2), InstID, Vals, VE);
1269     break;
1270   case Instruction::ICmp:
1271   case Instruction::FCmp:
1272     // compare returning Int1Ty or vector of Int1Ty
1273     Code = bitc::FUNC_CODE_INST_CMP2;
1274     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1275     pushValue(I.getOperand(1), InstID, Vals, VE);
1276     Vals.push_back(cast<CmpInst>(I).getPredicate());
1277     break;
1278
1279   case Instruction::Ret:
1280     {
1281       Code = bitc::FUNC_CODE_INST_RET;
1282       unsigned NumOperands = I.getNumOperands();
1283       if (NumOperands == 0)
1284         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1285       else if (NumOperands == 1) {
1286         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1287           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1288       } else {
1289         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1290           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1291       }
1292     }
1293     break;
1294   case Instruction::Br:
1295     {
1296       Code = bitc::FUNC_CODE_INST_BR;
1297       const BranchInst &II = cast<BranchInst>(I);
1298       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1299       if (II.isConditional()) {
1300         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1301         pushValue(II.getCondition(), InstID, Vals, VE);
1302       }
1303     }
1304     break;
1305   case Instruction::Switch:
1306     {
1307       Code = bitc::FUNC_CODE_INST_SWITCH;
1308       const SwitchInst &SI = cast<SwitchInst>(I);
1309       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1310       pushValue(SI.getCondition(), InstID, Vals, VE);
1311       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1312       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1313            i != e; ++i) {
1314         Vals.push_back(VE.getValueID(i.getCaseValue()));
1315         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1316       }
1317     }
1318     break;
1319   case Instruction::IndirectBr:
1320     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1321     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1322     // Encode the address operand as relative, but not the basic blocks.
1323     pushValue(I.getOperand(0), InstID, Vals, VE);
1324     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1325       Vals.push_back(VE.getValueID(I.getOperand(i)));
1326     break;
1327
1328   case Instruction::Invoke: {
1329     const InvokeInst *II = cast<InvokeInst>(&I);
1330     const Value *Callee(II->getCalledValue());
1331     PointerType *PTy = cast<PointerType>(Callee->getType());
1332     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1333     Code = bitc::FUNC_CODE_INST_INVOKE;
1334
1335     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1336     Vals.push_back(II->getCallingConv());
1337     Vals.push_back(VE.getValueID(II->getNormalDest()));
1338     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1339     PushValueAndType(Callee, InstID, Vals, VE);
1340
1341     // Emit value #'s for the fixed parameters.
1342     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1343       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1344
1345     // Emit type/value pairs for varargs params.
1346     if (FTy->isVarArg()) {
1347       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1348            i != e; ++i)
1349         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1350     }
1351     break;
1352   }
1353   case Instruction::Resume:
1354     Code = bitc::FUNC_CODE_INST_RESUME;
1355     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1356     break;
1357   case Instruction::Unreachable:
1358     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1359     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1360     break;
1361
1362   case Instruction::PHI: {
1363     const PHINode &PN = cast<PHINode>(I);
1364     Code = bitc::FUNC_CODE_INST_PHI;
1365     // With the newer instruction encoding, forward references could give
1366     // negative valued IDs.  This is most common for PHIs, so we use
1367     // signed VBRs.
1368     SmallVector<uint64_t, 128> Vals64;
1369     Vals64.push_back(VE.getTypeID(PN.getType()));
1370     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1371       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1372       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1373     }
1374     // Emit a Vals64 vector and exit.
1375     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1376     Vals64.clear();
1377     return;
1378   }
1379
1380   case Instruction::LandingPad: {
1381     const LandingPadInst &LP = cast<LandingPadInst>(I);
1382     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1383     Vals.push_back(VE.getTypeID(LP.getType()));
1384     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1385     Vals.push_back(LP.isCleanup());
1386     Vals.push_back(LP.getNumClauses());
1387     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1388       if (LP.isCatch(I))
1389         Vals.push_back(LandingPadInst::Catch);
1390       else
1391         Vals.push_back(LandingPadInst::Filter);
1392       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1393     }
1394     break;
1395   }
1396
1397   case Instruction::Alloca:
1398     Code = bitc::FUNC_CODE_INST_ALLOCA;
1399     Vals.push_back(VE.getTypeID(I.getType()));
1400     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1401     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1402     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1403     break;
1404
1405   case Instruction::Load:
1406     if (cast<LoadInst>(I).isAtomic()) {
1407       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1408       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1409     } else {
1410       Code = bitc::FUNC_CODE_INST_LOAD;
1411       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1412         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1413     }
1414     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1415     Vals.push_back(cast<LoadInst>(I).isVolatile());
1416     if (cast<LoadInst>(I).isAtomic()) {
1417       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1418       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1419     }
1420     break;
1421   case Instruction::Store:
1422     if (cast<StoreInst>(I).isAtomic())
1423       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1424     else
1425       Code = bitc::FUNC_CODE_INST_STORE;
1426     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1427     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1428     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1429     Vals.push_back(cast<StoreInst>(I).isVolatile());
1430     if (cast<StoreInst>(I).isAtomic()) {
1431       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1432       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1433     }
1434     break;
1435   case Instruction::AtomicCmpXchg:
1436     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1437     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1438     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1439     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1440     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1441     Vals.push_back(GetEncodedOrdering(
1442                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1443     Vals.push_back(GetEncodedSynchScope(
1444                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1445     Vals.push_back(GetEncodedOrdering(
1446                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1447     break;
1448   case Instruction::AtomicRMW:
1449     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1450     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1451     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1452     Vals.push_back(GetEncodedRMWOperation(
1453                      cast<AtomicRMWInst>(I).getOperation()));
1454     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1455     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1456     Vals.push_back(GetEncodedSynchScope(
1457                      cast<AtomicRMWInst>(I).getSynchScope()));
1458     break;
1459   case Instruction::Fence:
1460     Code = bitc::FUNC_CODE_INST_FENCE;
1461     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1462     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1463     break;
1464   case Instruction::Call: {
1465     const CallInst &CI = cast<CallInst>(I);
1466     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1467     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1468
1469     Code = bitc::FUNC_CODE_INST_CALL;
1470
1471     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1472     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1473     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1474
1475     // Emit value #'s for the fixed parameters.
1476     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1477       // Check for labels (can happen with asm labels).
1478       if (FTy->getParamType(i)->isLabelTy())
1479         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1480       else
1481         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1482     }
1483
1484     // Emit type/value pairs for varargs params.
1485     if (FTy->isVarArg()) {
1486       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1487            i != e; ++i)
1488         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1489     }
1490     break;
1491   }
1492   case Instruction::VAArg:
1493     Code = bitc::FUNC_CODE_INST_VAARG;
1494     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1495     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1496     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1497     break;
1498   }
1499
1500   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1501   Vals.clear();
1502 }
1503
1504 // Emit names for globals/functions etc.
1505 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1506                                   const ValueEnumerator &VE,
1507                                   BitstreamWriter &Stream) {
1508   if (VST.empty()) return;
1509   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1510
1511   // FIXME: Set up the abbrev, we know how many values there are!
1512   // FIXME: We know if the type names can use 7-bit ascii.
1513   SmallVector<unsigned, 64> NameVals;
1514
1515   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1516        SI != SE; ++SI) {
1517
1518     const ValueName &Name = *SI;
1519
1520     // Figure out the encoding to use for the name.
1521     bool is7Bit = true;
1522     bool isChar6 = true;
1523     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1524          C != E; ++C) {
1525       if (isChar6)
1526         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1527       if ((unsigned char)*C & 128) {
1528         is7Bit = false;
1529         break;  // don't bother scanning the rest.
1530       }
1531     }
1532
1533     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1534
1535     // VST_ENTRY:   [valueid, namechar x N]
1536     // VST_BBENTRY: [bbid, namechar x N]
1537     unsigned Code;
1538     if (isa<BasicBlock>(SI->getValue())) {
1539       Code = bitc::VST_CODE_BBENTRY;
1540       if (isChar6)
1541         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1542     } else {
1543       Code = bitc::VST_CODE_ENTRY;
1544       if (isChar6)
1545         AbbrevToUse = VST_ENTRY_6_ABBREV;
1546       else if (is7Bit)
1547         AbbrevToUse = VST_ENTRY_7_ABBREV;
1548     }
1549
1550     NameVals.push_back(VE.getValueID(SI->getValue()));
1551     for (const char *P = Name.getKeyData(),
1552          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1553       NameVals.push_back((unsigned char)*P);
1554
1555     // Emit the finished record.
1556     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1557     NameVals.clear();
1558   }
1559   Stream.ExitBlock();
1560 }
1561
1562 /// WriteFunction - Emit a function body to the module stream.
1563 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1564                           BitstreamWriter &Stream) {
1565   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1566   VE.incorporateFunction(F);
1567
1568   SmallVector<unsigned, 64> Vals;
1569
1570   // Emit the number of basic blocks, so the reader can create them ahead of
1571   // time.
1572   Vals.push_back(VE.getBasicBlocks().size());
1573   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1574   Vals.clear();
1575
1576   // If there are function-local constants, emit them now.
1577   unsigned CstStart, CstEnd;
1578   VE.getFunctionConstantRange(CstStart, CstEnd);
1579   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1580
1581   // If there is function-local metadata, emit it now.
1582   WriteFunctionLocalMetadata(F, VE, Stream);
1583
1584   // Keep a running idea of what the instruction ID is.
1585   unsigned InstID = CstEnd;
1586
1587   bool NeedsMetadataAttachment = false;
1588
1589   DebugLoc LastDL;
1590
1591   // Finally, emit all the instructions, in order.
1592   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1593     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1594          I != E; ++I) {
1595       WriteInstruction(*I, InstID, VE, Stream, Vals);
1596
1597       if (!I->getType()->isVoidTy())
1598         ++InstID;
1599
1600       // If the instruction has metadata, write a metadata attachment later.
1601       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1602
1603       // If the instruction has a debug location, emit it.
1604       DebugLoc DL = I->getDebugLoc();
1605       if (DL.isUnknown()) {
1606         // nothing todo.
1607       } else if (DL == LastDL) {
1608         // Just repeat the same debug loc as last time.
1609         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1610       } else {
1611         MDNode *Scope, *IA;
1612         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1613
1614         Vals.push_back(DL.getLine());
1615         Vals.push_back(DL.getCol());
1616         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1617         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1618         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1619         Vals.clear();
1620
1621         LastDL = DL;
1622       }
1623     }
1624
1625   // Emit names for all the instructions etc.
1626   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1627
1628   if (NeedsMetadataAttachment)
1629     WriteMetadataAttachment(F, VE, Stream);
1630   VE.purgeFunction();
1631   Stream.ExitBlock();
1632 }
1633
1634 // Emit blockinfo, which defines the standard abbreviations etc.
1635 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1636   // We only want to emit block info records for blocks that have multiple
1637   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1638   // Other blocks can define their abbrevs inline.
1639   Stream.EnterBlockInfoBlock(2);
1640
1641   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1642     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1645     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1647     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1648                                    Abbv) != VST_ENTRY_8_ABBREV)
1649       llvm_unreachable("Unexpected abbrev ordering!");
1650   }
1651
1652   { // 7-bit fixed width VST_ENTRY strings.
1653     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1654     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1655     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1658     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1659                                    Abbv) != VST_ENTRY_7_ABBREV)
1660       llvm_unreachable("Unexpected abbrev ordering!");
1661   }
1662   { // 6-bit char6 VST_ENTRY strings.
1663     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1664     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1666     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1668     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1669                                    Abbv) != VST_ENTRY_6_ABBREV)
1670       llvm_unreachable("Unexpected abbrev ordering!");
1671   }
1672   { // 6-bit char6 VST_BBENTRY strings.
1673     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1674     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1678     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1679                                    Abbv) != VST_BBENTRY_6_ABBREV)
1680       llvm_unreachable("Unexpected abbrev ordering!");
1681   }
1682
1683
1684
1685   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1686     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1687     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1688     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1689                               Log2_32_Ceil(VE.getTypes().size()+1)));
1690     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1691                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1692       llvm_unreachable("Unexpected abbrev ordering!");
1693   }
1694
1695   { // INTEGER abbrev for CONSTANTS_BLOCK.
1696     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1697     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1698     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1699     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1700                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1701       llvm_unreachable("Unexpected abbrev ordering!");
1702   }
1703
1704   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1705     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1706     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1707     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1708     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1709                               Log2_32_Ceil(VE.getTypes().size()+1)));
1710     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1711
1712     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1713                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1714       llvm_unreachable("Unexpected abbrev ordering!");
1715   }
1716   { // NULL abbrev for CONSTANTS_BLOCK.
1717     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1718     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1719     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1720                                    Abbv) != CONSTANTS_NULL_Abbrev)
1721       llvm_unreachable("Unexpected abbrev ordering!");
1722   }
1723
1724   // FIXME: This should only use space for first class types!
1725
1726   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1727     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1728     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1729     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1730     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1731     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1732     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1733                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1734       llvm_unreachable("Unexpected abbrev ordering!");
1735   }
1736   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1737     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1738     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1739     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1740     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1741     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1742     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1743                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1744       llvm_unreachable("Unexpected abbrev ordering!");
1745   }
1746   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1747     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1748     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1749     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1750     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1751     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1752     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1753     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1754                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1755       llvm_unreachable("Unexpected abbrev ordering!");
1756   }
1757   { // INST_CAST abbrev for FUNCTION_BLOCK.
1758     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1759     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1760     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1761     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1762                               Log2_32_Ceil(VE.getTypes().size()+1)));
1763     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1764     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1765                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1766       llvm_unreachable("Unexpected abbrev ordering!");
1767   }
1768
1769   { // INST_RET abbrev for FUNCTION_BLOCK.
1770     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1771     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1772     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1773                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1774       llvm_unreachable("Unexpected abbrev ordering!");
1775   }
1776   { // INST_RET abbrev for FUNCTION_BLOCK.
1777     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1778     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1779     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1780     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1781                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1782       llvm_unreachable("Unexpected abbrev ordering!");
1783   }
1784   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1785     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1786     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1787     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1788                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1789       llvm_unreachable("Unexpected abbrev ordering!");
1790   }
1791
1792   Stream.ExitBlock();
1793 }
1794
1795 // Sort the Users based on the order in which the reader parses the bitcode
1796 // file.
1797 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1798   // TODO: Implement.
1799   return true;
1800 }
1801
1802 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1803                          BitstreamWriter &Stream) {
1804
1805   // One or zero uses can't get out of order.
1806   if (V->use_empty() || V->hasNUses(1))
1807     return;
1808
1809   // Make a copy of the in-memory use-list for sorting.
1810   SmallVector<const User*, 8> UserList(V->user_begin(), V->user_end());
1811
1812   // Sort the copy based on the order read by the BitcodeReader.
1813   std::sort(UserList.begin(), UserList.end(), bitcodereader_order);
1814
1815   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1816   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1817
1818   // TODO: Emit the USELIST_CODE_ENTRYs.
1819 }
1820
1821 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1822                                  BitstreamWriter &Stream) {
1823   VE.incorporateFunction(*F);
1824
1825   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1826        AI != AE; ++AI)
1827     WriteUseList(AI, VE, Stream);
1828   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1829        ++BB) {
1830     WriteUseList(BB, VE, Stream);
1831     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1832          ++II) {
1833       WriteUseList(II, VE, Stream);
1834       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1835            OI != E; ++OI) {
1836         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1837             isa<InlineAsm>(*OI))
1838           WriteUseList(*OI, VE, Stream);
1839       }
1840     }
1841   }
1842   VE.purgeFunction();
1843 }
1844
1845 // Emit use-lists.
1846 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1847                                 BitstreamWriter &Stream) {
1848   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1849
1850   // XXX: this modifies the module, but in a way that should never change the
1851   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1852   // contain entries in the use_list that do not exist in the Module and are
1853   // not stored in the .bc file.
1854   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1855        I != E; ++I)
1856     I->removeDeadConstantUsers();
1857
1858   // Write the global variables.
1859   for (Module::const_global_iterator GI = M->global_begin(),
1860          GE = M->global_end(); GI != GE; ++GI) {
1861     WriteUseList(GI, VE, Stream);
1862
1863     // Write the global variable initializers.
1864     if (GI->hasInitializer())
1865       WriteUseList(GI->getInitializer(), VE, Stream);
1866   }
1867
1868   // Write the functions.
1869   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1870     WriteUseList(FI, VE, Stream);
1871     if (!FI->isDeclaration())
1872       WriteFunctionUseList(FI, VE, Stream);
1873     if (FI->hasPrefixData())
1874       WriteUseList(FI->getPrefixData(), VE, Stream);
1875   }
1876
1877   // Write the aliases.
1878   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1879        AI != AE; ++AI) {
1880     WriteUseList(AI, VE, Stream);
1881     WriteUseList(AI->getAliasee(), VE, Stream);
1882   }
1883
1884   Stream.ExitBlock();
1885 }
1886
1887 /// WriteModule - Emit the specified module to the bitstream.
1888 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1889   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1890
1891   SmallVector<unsigned, 1> Vals;
1892   unsigned CurVersion = 1;
1893   Vals.push_back(CurVersion);
1894   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1895
1896   // Analyze the module, enumerating globals, functions, etc.
1897   ValueEnumerator VE(M);
1898
1899   // Emit blockinfo, which defines the standard abbreviations etc.
1900   WriteBlockInfo(VE, Stream);
1901
1902   // Emit information about attribute groups.
1903   WriteAttributeGroupTable(VE, Stream);
1904
1905   // Emit information about parameter attributes.
1906   WriteAttributeTable(VE, Stream);
1907
1908   // Emit information describing all of the types in the module.
1909   WriteTypeTable(VE, Stream);
1910
1911   // Emit top-level description of module, including target triple, inline asm,
1912   // descriptors for global variables, and function prototype info.
1913   WriteModuleInfo(M, VE, Stream);
1914
1915   // Emit constants.
1916   WriteModuleConstants(VE, Stream);
1917
1918   // Emit metadata.
1919   WriteModuleMetadata(M, VE, Stream);
1920
1921   // Emit metadata.
1922   WriteModuleMetadataStore(M, Stream);
1923
1924   // Emit names for globals/functions etc.
1925   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1926
1927   // Emit use-lists.
1928   if (EnablePreserveUseListOrdering)
1929     WriteModuleUseLists(M, VE, Stream);
1930
1931   // Emit function bodies.
1932   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1933     if (!F->isDeclaration())
1934       WriteFunction(*F, VE, Stream);
1935
1936   Stream.ExitBlock();
1937 }
1938
1939 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1940 /// header and trailer to make it compatible with the system archiver.  To do
1941 /// this we emit the following header, and then emit a trailer that pads the
1942 /// file out to be a multiple of 16 bytes.
1943 ///
1944 /// struct bc_header {
1945 ///   uint32_t Magic;         // 0x0B17C0DE
1946 ///   uint32_t Version;       // Version, currently always 0.
1947 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1948 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1949 ///   uint32_t CPUType;       // CPU specifier.
1950 ///   ... potentially more later ...
1951 /// };
1952 enum {
1953   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1954   DarwinBCHeaderSize = 5*4
1955 };
1956
1957 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1958                                uint32_t &Position) {
1959   Buffer[Position + 0] = (unsigned char) (Value >>  0);
1960   Buffer[Position + 1] = (unsigned char) (Value >>  8);
1961   Buffer[Position + 2] = (unsigned char) (Value >> 16);
1962   Buffer[Position + 3] = (unsigned char) (Value >> 24);
1963   Position += 4;
1964 }
1965
1966 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1967                                          const Triple &TT) {
1968   unsigned CPUType = ~0U;
1969
1970   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1971   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1972   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1973   // specific constants here because they are implicitly part of the Darwin ABI.
1974   enum {
1975     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1976     DARWIN_CPU_TYPE_X86        = 7,
1977     DARWIN_CPU_TYPE_ARM        = 12,
1978     DARWIN_CPU_TYPE_POWERPC    = 18
1979   };
1980
1981   Triple::ArchType Arch = TT.getArch();
1982   if (Arch == Triple::x86_64)
1983     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1984   else if (Arch == Triple::x86)
1985     CPUType = DARWIN_CPU_TYPE_X86;
1986   else if (Arch == Triple::ppc)
1987     CPUType = DARWIN_CPU_TYPE_POWERPC;
1988   else if (Arch == Triple::ppc64)
1989     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1990   else if (Arch == Triple::arm || Arch == Triple::thumb)
1991     CPUType = DARWIN_CPU_TYPE_ARM;
1992
1993   // Traditional Bitcode starts after header.
1994   assert(Buffer.size() >= DarwinBCHeaderSize &&
1995          "Expected header size to be reserved");
1996   unsigned BCOffset = DarwinBCHeaderSize;
1997   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
1998
1999   // Write the magic and version.
2000   unsigned Position = 0;
2001   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2002   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2003   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2004   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2005   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2006
2007   // If the file is not a multiple of 16 bytes, insert dummy padding.
2008   while (Buffer.size() & 15)
2009     Buffer.push_back(0);
2010 }
2011
2012 /// WriteBitcodeToFile - Write the specified module to the specified output
2013 /// stream.
2014 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2015   SmallVector<char, 0> Buffer;
2016   Buffer.reserve(256*1024);
2017
2018   // If this is darwin or another generic macho target, reserve space for the
2019   // header.
2020   Triple TT(M->getTargetTriple());
2021   if (TT.isOSDarwin())
2022     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2023
2024   // Emit the module into the buffer.
2025   {
2026     BitstreamWriter Stream(Buffer);
2027
2028     // Emit the file header.
2029     Stream.Emit((unsigned)'B', 8);
2030     Stream.Emit((unsigned)'C', 8);
2031     Stream.Emit(0x0, 4);
2032     Stream.Emit(0xC, 4);
2033     Stream.Emit(0xE, 4);
2034     Stream.Emit(0xD, 4);
2035
2036     // Emit the module.
2037     WriteModule(M, Stream);
2038   }
2039
2040   if (TT.isOSDarwin())
2041     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2042
2043   // Write the generated bitstream to "Out".
2044   Out.write((char*)&Buffer.front(), Buffer.size());
2045 }