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.isIntAttribute()) {
 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 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 528   switch (C.getSelectionKind()) {
 529   case Comdat::Any:
 530     return bitc::COMDAT_SELECTION_KIND_ANY;
 531   case Comdat::ExactMatch:
 532     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 533   case Comdat::Largest:
 534     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 535   case Comdat::NoDuplicates:
 536     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 537   case Comdat::SameSize:
 538     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 539   }
 540   llvm_unreachable("Invalid selection kind");
 541 }
 542
 543 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 544   SmallVector<uint8_t, 64> Vals;
 545   for (const Comdat *C : VE.getComdats()) {
 546     // COMDAT: [selection_kind, name]
 547     Vals.push_back(getEncodedComdatSelectionKind(*C));
 548     Vals.push_back(C->getName().size());
 549     for (char Chr : C->getName())
 550       Vals.push_back((unsigned char)Chr);
 551     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 552     Vals.clear();
 553   }
 554 }
 555
 556 // Emit top-level description of module, including target triple, inline asm,
 557 // descriptors for global variables, and function prototype info.
 558 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 559                             BitstreamWriter &Stream) {
 560   // Emit various pieces of data attached to a module.
 561   if (!M->getTargetTriple().empty())
 562     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 563                       0/*TODO*/, Stream);
 564   const std::string &DL = M->getDataLayoutStr();
 565   if (!DL.empty())
 566     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 567   if (!M->getModuleInlineAsm().empty())
 568     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 569                       0/*TODO*/, Stream);
 570
 571   // Emit information about sections and GC, computing how many there are. Also
 572   // compute the maximum alignment value.
 573   std::map<std::string, unsigned> SectionMap;
 574   std::map<std::string, unsigned> GCMap;
 575   unsigned MaxAlignment = 0;
 576   unsigned MaxGlobalType = 0;
 577   for (const GlobalValue &GV : M->globals()) {
 578     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 579     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 580     if (GV.hasSection()) {
 581       // Give section names unique ID's.
 582       unsigned &Entry = SectionMap[GV.getSection()];
 583       if (!Entry) {
 584         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 585                           0/*TODO*/, Stream);
 586         Entry = SectionMap.size();
 587       }
 588     }
 589   }
 590   for (const Function &F : *M) {
 591     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 592     if (F.hasSection()) {
 593       // Give section names unique ID's.
 594       unsigned &Entry = SectionMap[F.getSection()];
 595       if (!Entry) {
 596         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 597                           0/*TODO*/, Stream);
 598         Entry = SectionMap.size();
 599       }
 600     }
 601     if (F.hasGC()) {
 602       // Same for GC names.
 603       unsigned &Entry = GCMap[F.getGC()];
 604       if (!Entry) {
 605         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 606                           0/*TODO*/, Stream);
 607         Entry = GCMap.size();
 608       }
 609     }
 610   }
 611
 612   // Emit abbrev for globals, now that we know # sections and max alignment.
 613   unsigned SimpleGVarAbbrev = 0;
 614   if (!M->global_empty()) {
 615     // Add an abbrev for common globals with no visibility or thread localness.
 616     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 617     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 618     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 619                               Log2_32_Ceil(MaxGlobalType+1)));
 620     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 621     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 623     if (MaxAlignment == 0)                                      // Alignment.
 624       Abbv->Add(BitCodeAbbrevOp(0));
 625     else {
 626       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 627       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 628                                Log2_32_Ceil(MaxEncAlignment+1)));
 629     }
 630     if (SectionMap.empty())                                    // Section.
 631       Abbv->Add(BitCodeAbbrevOp(0));
 632     else
 633       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 634                                Log2_32_Ceil(SectionMap.size()+1)));
 635     // Don't bother emitting vis + thread local.
 636     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 637   }
 638
 639   // Emit the global variable information.
 640   SmallVector<unsigned, 64> Vals;
 641   for (const GlobalVariable &GV : M->globals()) {
 642     unsigned AbbrevToUse = 0;
 643
 644     // GLOBALVAR: [type, isconst, initid,
 645     //             linkage, alignment, section, visibility, threadlocal,
 646     //             unnamed_addr, externally_initialized, dllstorageclass]
 647     Vals.push_back(VE.getTypeID(GV.getType()));
 648     Vals.push_back(GV.isConstant());
 649     Vals.push_back(GV.isDeclaration() ? 0 :
 650                    (VE.getValueID(GV.getInitializer()) + 1));
 651     Vals.push_back(getEncodedLinkage(GV));
 652     Vals.push_back(Log2_32(GV.getAlignment())+1);
 653     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 654     if (GV.isThreadLocal() ||
 655         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 656         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 657         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 658         GV.hasComdat()) {
 659       Vals.push_back(getEncodedVisibility(GV));
 660       Vals.push_back(getEncodedThreadLocalMode(GV));
 661       Vals.push_back(GV.hasUnnamedAddr());
 662       Vals.push_back(GV.isExternallyInitialized());
 663       Vals.push_back(getEncodedDLLStorageClass(GV));
 664       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 665     } else {
 666       AbbrevToUse = SimpleGVarAbbrev;
 667     }
 668
 669     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 670     Vals.clear();
 671   }
 672
 673   // Emit the function proto information.
 674   for (const Function &F : *M) {
 675     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 676     //             section, visibility, gc, unnamed_addr, prefix]
 677     Vals.push_back(VE.getTypeID(F.getType()));
 678     Vals.push_back(F.getCallingConv());
 679     Vals.push_back(F.isDeclaration());
 680     Vals.push_back(getEncodedLinkage(F));
 681     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 682     Vals.push_back(Log2_32(F.getAlignment())+1);
 683     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 684     Vals.push_back(getEncodedVisibility(F));
 685     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 686     Vals.push_back(F.hasUnnamedAddr());
 687     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 688                                       : 0);
 689     Vals.push_back(getEncodedDLLStorageClass(F));
 690     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 691
 692     unsigned AbbrevToUse = 0;
 693     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 694     Vals.clear();
 695   }
 696
 697   // Emit the alias information.
 698   for (const GlobalAlias &A : M->aliases()) {
 699     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 700     Vals.push_back(VE.getTypeID(A.getType()));
 701     Vals.push_back(VE.getValueID(A.getAliasee()));
 702     Vals.push_back(getEncodedLinkage(A));
 703     Vals.push_back(getEncodedVisibility(A));
 704     Vals.push_back(getEncodedDLLStorageClass(A));
 705     Vals.push_back(getEncodedThreadLocalMode(A));
 706     Vals.push_back(A.hasUnnamedAddr());
 707     unsigned AbbrevToUse = 0;
 708     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 709     Vals.clear();
 710   }
 711 }
 712
 713 static uint64_t GetOptimizationFlags(const Value *V) {
 714   uint64_t Flags = 0;
 715
 716   if (const OverflowingBinaryOperator *OBO =
 717         dyn_cast<OverflowingBinaryOperator>(V)) {
 718     if (OBO->hasNoSignedWrap())
 719       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 720     if (OBO->hasNoUnsignedWrap())
 721       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 722   } else if (const PossiblyExactOperator *PEO =
 723                dyn_cast<PossiblyExactOperator>(V)) {
 724     if (PEO->isExact())
 725       Flags |= 1 << bitc::PEO_EXACT;
 726   } else if (const FPMathOperator *FPMO =
 727              dyn_cast<const FPMathOperator>(V)) {
 728     if (FPMO->hasUnsafeAlgebra())
 729       Flags |= FastMathFlags::UnsafeAlgebra;
 730     if (FPMO->hasNoNaNs())
 731       Flags |= FastMathFlags::NoNaNs;
 732     if (FPMO->hasNoInfs())
 733       Flags |= FastMathFlags::NoInfs;
 734     if (FPMO->hasNoSignedZeros())
 735       Flags |= FastMathFlags::NoSignedZeros;
 736     if (FPMO->hasAllowReciprocal())
 737       Flags |= FastMathFlags::AllowReciprocal;
 738   }
 739
 740   return Flags;
 741 }
 742
 743 static void WriteMDNode(const MDNode *N,
 744                         const ValueEnumerator &VE,
 745                         BitstreamWriter &Stream,
 746                         SmallVectorImpl<uint64_t> &Record) {
 747   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 748     if (N->getOperand(i)) {
 749       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 750       Record.push_back(VE.getValueID(N->getOperand(i)));
 751     } else {
 752       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 753       Record.push_back(0);
 754     }
 755   }
 756   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 757                                            bitc::METADATA_NODE;
 758   Stream.EmitRecord(MDCode, Record, 0);
 759   Record.clear();
 760 }
 761
 762 static void WriteModuleMetadata(const Module *M,
 763                                 const ValueEnumerator &VE,
 764                                 BitstreamWriter &Stream) {
 765   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 766   bool StartedMetadataBlock = false;
 767   unsigned MDSAbbrev = 0;
 768   SmallVector<uint64_t, 64> Record;
 769   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 770
 771     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 772       if (!N->isFunctionLocal() || !N->getFunction()) {
 773         if (!StartedMetadataBlock) {
 774           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 775           StartedMetadataBlock = true;
 776         }
 777         WriteMDNode(N, VE, Stream, Record);
 778       }
 779     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 780       if (!StartedMetadataBlock)  {
 781         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 782
 783         // Abbrev for METADATA_STRING.
 784         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 785         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 786         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 787         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 788         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 789         StartedMetadataBlock = true;
 790       }
 791
 792       // Code: [strchar x N]
 793       Record.append(MDS->begin(), MDS->end());
 794
 795       // Emit the finished record.
 796       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 797       Record.clear();
 798     }
 799   }
 800
 801   // Write named metadata.
 802   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 803        E = M->named_metadata_end(); I != E; ++I) {
 804     const NamedMDNode *NMD = I;
 805     if (!StartedMetadataBlock)  {
 806       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 807       StartedMetadataBlock = true;
 808     }
 809
 810     // Write name.
 811     StringRef Str = NMD->getName();
 812     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 813       Record.push_back(Str[i]);
 814     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 815     Record.clear();
 816
 817     // Write named metadata operands.
 818     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 819       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 820     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 821     Record.clear();
 822   }
 823
 824   if (StartedMetadataBlock)
 825     Stream.ExitBlock();
 826 }
 827
 828 static void WriteFunctionLocalMetadata(const Function &F,
 829                                        const ValueEnumerator &VE,
 830                                        BitstreamWriter &Stream) {
 831   bool StartedMetadataBlock = false;
 832   SmallVector<uint64_t, 64> Record;
 833   const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
 834   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 835     if (const MDNode *N = Vals[i])
 836       if (N->isFunctionLocal() && N->getFunction() == &F) {
 837         if (!StartedMetadataBlock) {
 838           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 839           StartedMetadataBlock = true;
 840         }
 841         WriteMDNode(N, VE, Stream, Record);
 842       }
 843
 844   if (StartedMetadataBlock)
 845     Stream.ExitBlock();
 846 }
 847
 848 static void WriteMetadataAttachment(const Function &F,
 849                                     const ValueEnumerator &VE,
 850                                     BitstreamWriter &Stream) {
 851   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 852
 853   SmallVector<uint64_t, 64> Record;
 854
 855   // Write metadata attachments
 856   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 857   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 858
 859   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 860     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 861          I != E; ++I) {
 862       MDs.clear();
 863       I->getAllMetadataOtherThanDebugLoc(MDs);
 864
 865       // If no metadata, ignore instruction.
 866       if (MDs.empty()) continue;
 867
 868       Record.push_back(VE.getInstructionID(I));
 869
 870       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 871         Record.push_back(MDs[i].first);
 872         Record.push_back(VE.getValueID(MDs[i].second));
 873       }
 874       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 875       Record.clear();
 876     }
 877
 878   Stream.ExitBlock();
 879 }
 880
 881 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 882   SmallVector<uint64_t, 64> Record;
 883
 884   // Write metadata kinds
 885   // METADATA_KIND - [n x [id, name]]
 886   SmallVector<StringRef, 8> Names;
 887   M->getMDKindNames(Names);
 888
 889   if (Names.empty()) return;
 890
 891   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 892
 893   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 894     Record.push_back(MDKindID);
 895     StringRef KName = Names[MDKindID];
 896     Record.append(KName.begin(), KName.end());
 897
 898     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 899     Record.clear();
 900   }
 901
 902   Stream.ExitBlock();
 903 }
 904
 905 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 906   if ((int64_t)V >= 0)
 907     Vals.push_back(V << 1);
 908   else
 909     Vals.push_back((-V << 1) | 1);
 910 }
 911
 912 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 913                            const ValueEnumerator &VE,
 914                            BitstreamWriter &Stream, bool isGlobal) {
 915   if (FirstVal == LastVal) return;
 916
 917   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 918
 919   unsigned AggregateAbbrev = 0;
 920   unsigned String8Abbrev = 0;
 921   unsigned CString7Abbrev = 0;
 922   unsigned CString6Abbrev = 0;
 923   // If this is a constant pool for the module, emit module-specific abbrevs.
 924   if (isGlobal) {
 925     // Abbrev for CST_CODE_AGGREGATE.
 926     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 927     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 930     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 931
 932     // Abbrev for CST_CODE_STRING.
 933     Abbv = new BitCodeAbbrev();
 934     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 935     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 936     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 937     String8Abbrev = Stream.EmitAbbrev(Abbv);
 938     // Abbrev for CST_CODE_CSTRING.
 939     Abbv = new BitCodeAbbrev();
 940     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 941     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 942     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 943     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 944     // Abbrev for CST_CODE_CSTRING.
 945     Abbv = new BitCodeAbbrev();
 946     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 947     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 948     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 949     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 950   }
 951
 952   SmallVector<uint64_t, 64> Record;
 953
 954   const ValueEnumerator::ValueList &Vals = VE.getValues();
 955   Type *LastTy = nullptr;
 956   for (unsigned i = FirstVal; i != LastVal; ++i) {
 957     const Value *V = Vals[i].first;
 958     // If we need to switch types, do so now.
 959     if (V->getType() != LastTy) {
 960       LastTy = V->getType();
 961       Record.push_back(VE.getTypeID(LastTy));
 962       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 963                         CONSTANTS_SETTYPE_ABBREV);
 964       Record.clear();
 965     }
 966
 967     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 968       Record.push_back(unsigned(IA->hasSideEffects()) |
 969                        unsigned(IA->isAlignStack()) << 1 |
 970                        unsigned(IA->getDialect()&1) << 2);
 971
 972       // Add the asm string.
 973       const std::string &AsmStr = IA->getAsmString();
 974       Record.push_back(AsmStr.size());
 975       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 976         Record.push_back(AsmStr[i]);
 977
 978       // Add the constraint string.
 979       const std::string &ConstraintStr = IA->getConstraintString();
 980       Record.push_back(ConstraintStr.size());
 981       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 982         Record.push_back(ConstraintStr[i]);
 983       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 984       Record.clear();
 985       continue;
 986     }
 987     const Constant *C = cast<Constant>(V);
 988     unsigned Code = -1U;
 989     unsigned AbbrevToUse = 0;
 990     if (C->isNullValue()) {
 991       Code = bitc::CST_CODE_NULL;
 992     } else if (isa<UndefValue>(C)) {
 993       Code = bitc::CST_CODE_UNDEF;
 994     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 995       if (IV->getBitWidth() <= 64) {
 996         uint64_t V = IV->getSExtValue();
 997         emitSignedInt64(Record, V);
 998         Code = bitc::CST_CODE_INTEGER;
 999         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1000       } else {                             // Wide integers, > 64 bits in size.
1001         // We have an arbitrary precision integer value to write whose
1002         // bit width is > 64. However, in canonical unsigned integer
1003         // format it is likely that the high bits are going to be zero.
1004         // So, we only write the number of active words.
1005         unsigned NWords = IV->getValue().getActiveWords();
1006         const uint64_t *RawWords = IV->getValue().getRawData();
1007         for (unsigned i = 0; i != NWords; ++i) {
1008           emitSignedInt64(Record, RawWords[i]);
1009         }
1010         Code = bitc::CST_CODE_WIDE_INTEGER;
1011       }
1012     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1013       Code = bitc::CST_CODE_FLOAT;
1014       Type *Ty = CFP->getType();
1015       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1016         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1017       } else if (Ty->isX86_FP80Ty()) {
1018         // api needed to prevent premature destruction
1019         // bits are not in the same order as a normal i80 APInt, compensate.
1020         APInt api = CFP->getValueAPF().bitcastToAPInt();
1021         const uint64_t *p = api.getRawData();
1022         Record.push_back((p[1] << 48) | (p[0] >> 16));
1023         Record.push_back(p[0] & 0xffffLL);
1024       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1025         APInt api = CFP->getValueAPF().bitcastToAPInt();
1026         const uint64_t *p = api.getRawData();
1027         Record.push_back(p[0]);
1028         Record.push_back(p[1]);
1029       } else {
1030         assert (0 && "Unknown FP type!");
1031       }
1032     } else if (isa<ConstantDataSequential>(C) &&
1033                cast<ConstantDataSequential>(C)->isString()) {
1034       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1035       // Emit constant strings specially.
1036       unsigned NumElts = Str->getNumElements();
1037       // If this is a null-terminated string, use the denser CSTRING encoding.
1038       if (Str->isCString()) {
1039         Code = bitc::CST_CODE_CSTRING;
1040         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1041       } else {
1042         Code = bitc::CST_CODE_STRING;
1043         AbbrevToUse = String8Abbrev;
1044       }
1045       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1046       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1047       for (unsigned i = 0; i != NumElts; ++i) {
1048         unsigned char V = Str->getElementAsInteger(i);
1049         Record.push_back(V);
1050         isCStr7 &= (V & 128) == 0;
1051         if (isCStrChar6)
1052           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1053       }
1054
1055       if (isCStrChar6)
1056         AbbrevToUse = CString6Abbrev;
1057       else if (isCStr7)
1058         AbbrevToUse = CString7Abbrev;
1059     } else if (const ConstantDataSequential *CDS =
1060                   dyn_cast<ConstantDataSequential>(C)) {
1061       Code = bitc::CST_CODE_DATA;
1062       Type *EltTy = CDS->getType()->getElementType();
1063       if (isa<IntegerType>(EltTy)) {
1064         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1065           Record.push_back(CDS->getElementAsInteger(i));
1066       } else if (EltTy->isFloatTy()) {
1067         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1068           union { float F; uint32_t I; };
1069           F = CDS->getElementAsFloat(i);
1070           Record.push_back(I);
1071         }
1072       } else {
1073         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1074         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1075           union { double F; uint64_t I; };
1076           F = CDS->getElementAsDouble(i);
1077           Record.push_back(I);
1078         }
1079       }
1080     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1081                isa<ConstantVector>(C)) {
1082       Code = bitc::CST_CODE_AGGREGATE;
1083       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1084         Record.push_back(VE.getValueID(C->getOperand(i)));
1085       AbbrevToUse = AggregateAbbrev;
1086     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1087       switch (CE->getOpcode()) {
1088       default:
1089         if (Instruction::isCast(CE->getOpcode())) {
1090           Code = bitc::CST_CODE_CE_CAST;
1091           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1092           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1093           Record.push_back(VE.getValueID(C->getOperand(0)));
1094           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1095         } else {
1096           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1097           Code = bitc::CST_CODE_CE_BINOP;
1098           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1099           Record.push_back(VE.getValueID(C->getOperand(0)));
1100           Record.push_back(VE.getValueID(C->getOperand(1)));
1101           uint64_t Flags = GetOptimizationFlags(CE);
1102           if (Flags != 0)
1103             Record.push_back(Flags);
1104         }
1105         break;
1106       case Instruction::GetElementPtr:
1107         Code = bitc::CST_CODE_CE_GEP;
1108         if (cast<GEPOperator>(C)->isInBounds())
1109           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1110         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1111           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1112           Record.push_back(VE.getValueID(C->getOperand(i)));
1113         }
1114         break;
1115       case Instruction::Select:
1116         Code = bitc::CST_CODE_CE_SELECT;
1117         Record.push_back(VE.getValueID(C->getOperand(0)));
1118         Record.push_back(VE.getValueID(C->getOperand(1)));
1119         Record.push_back(VE.getValueID(C->getOperand(2)));
1120         break;
1121       case Instruction::ExtractElement:
1122         Code = bitc::CST_CODE_CE_EXTRACTELT;
1123         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1124         Record.push_back(VE.getValueID(C->getOperand(0)));
1125         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1126         Record.push_back(VE.getValueID(C->getOperand(1)));
1127         break;
1128       case Instruction::InsertElement:
1129         Code = bitc::CST_CODE_CE_INSERTELT;
1130         Record.push_back(VE.getValueID(C->getOperand(0)));
1131         Record.push_back(VE.getValueID(C->getOperand(1)));
1132         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1133         Record.push_back(VE.getValueID(C->getOperand(2)));
1134         break;
1135       case Instruction::ShuffleVector:
1136         // If the return type and argument types are the same, this is a
1137         // standard shufflevector instruction.  If the types are different,
1138         // then the shuffle is widening or truncating the input vectors, and
1139         // the argument type must also be encoded.
1140         if (C->getType() == C->getOperand(0)->getType()) {
1141           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1142         } else {
1143           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1144           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1145         }
1146         Record.push_back(VE.getValueID(C->getOperand(0)));
1147         Record.push_back(VE.getValueID(C->getOperand(1)));
1148         Record.push_back(VE.getValueID(C->getOperand(2)));
1149         break;
1150       case Instruction::ICmp:
1151       case Instruction::FCmp:
1152         Code = bitc::CST_CODE_CE_CMP;
1153         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1154         Record.push_back(VE.getValueID(C->getOperand(0)));
1155         Record.push_back(VE.getValueID(C->getOperand(1)));
1156         Record.push_back(CE->getPredicate());
1157         break;
1158       }
1159     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1160       Code = bitc::CST_CODE_BLOCKADDRESS;
1161       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1162       Record.push_back(VE.getValueID(BA->getFunction()));
1163       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1164     } else {
1165 #ifndef NDEBUG
1166       C->dump();
1167 #endif
1168       llvm_unreachable("Unknown constant!");
1169     }
1170     Stream.EmitRecord(Code, Record, AbbrevToUse);
1171     Record.clear();
1172   }
1173
1174   Stream.ExitBlock();
1175 }
1176
1177 static void WriteModuleConstants(const ValueEnumerator &VE,
1178                                  BitstreamWriter &Stream) {
1179   const ValueEnumerator::ValueList &Vals = VE.getValues();
1180
1181   // Find the first constant to emit, which is the first non-globalvalue value.
1182   // We know globalvalues have been emitted by WriteModuleInfo.
1183   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1184     if (!isa<GlobalValue>(Vals[i].first)) {
1185       WriteConstants(i, Vals.size(), VE, Stream, true);
1186       return;
1187     }
1188   }
1189 }
1190
1191 /// PushValueAndType - The file has to encode both the value and type id for
1192 /// many values, because we need to know what type to create for forward
1193 /// references.  However, most operands are not forward references, so this type
1194 /// field is not needed.
1195 ///
1196 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1197 /// instruction ID, then it is a forward reference, and it also includes the
1198 /// type ID.  The value ID that is written is encoded relative to the InstID.
1199 static bool PushValueAndType(const Value *V, unsigned InstID,
1200                              SmallVectorImpl<unsigned> &Vals,
1201                              ValueEnumerator &VE) {
1202   unsigned ValID = VE.getValueID(V);
1203   // Make encoding relative to the InstID.
1204   Vals.push_back(InstID - ValID);
1205   if (ValID >= InstID) {
1206     Vals.push_back(VE.getTypeID(V->getType()));
1207     return true;
1208   }
1209   return false;
1210 }
1211
1212 /// pushValue - Like PushValueAndType, but where the type of the value is
1213 /// omitted (perhaps it was already encoded in an earlier operand).
1214 static void pushValue(const Value *V, unsigned InstID,
1215                       SmallVectorImpl<unsigned> &Vals,
1216                       ValueEnumerator &VE) {
1217   unsigned ValID = VE.getValueID(V);
1218   Vals.push_back(InstID - ValID);
1219 }
1220
1221 static void pushValueSigned(const Value *V, unsigned InstID,
1222                             SmallVectorImpl<uint64_t> &Vals,
1223                             ValueEnumerator &VE) {
1224   unsigned ValID = VE.getValueID(V);
1225   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1226   emitSignedInt64(Vals, diff);
1227 }
1228
1229 /// WriteInstruction - Emit an instruction to the specified stream.
1230 static void WriteInstruction(const Instruction &I, unsigned InstID,
1231                              ValueEnumerator &VE, BitstreamWriter &Stream,
1232                              SmallVectorImpl<unsigned> &Vals) {
1233   unsigned Code = 0;
1234   unsigned AbbrevToUse = 0;
1235   VE.setInstructionID(&I);
1236   switch (I.getOpcode()) {
1237   default:
1238     if (Instruction::isCast(I.getOpcode())) {
1239       Code = bitc::FUNC_CODE_INST_CAST;
1240       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1241         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1242       Vals.push_back(VE.getTypeID(I.getType()));
1243       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1244     } else {
1245       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1246       Code = bitc::FUNC_CODE_INST_BINOP;
1247       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1248         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1249       pushValue(I.getOperand(1), InstID, Vals, VE);
1250       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1251       uint64_t Flags = GetOptimizationFlags(&I);
1252       if (Flags != 0) {
1253         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1254           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1255         Vals.push_back(Flags);
1256       }
1257     }
1258     break;
1259
1260   case Instruction::GetElementPtr:
1261     Code = bitc::FUNC_CODE_INST_GEP;
1262     if (cast<GEPOperator>(&I)->isInBounds())
1263       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1264     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1265       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1266     break;
1267   case Instruction::ExtractValue: {
1268     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1269     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1270     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1271     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1272       Vals.push_back(*i);
1273     break;
1274   }
1275   case Instruction::InsertValue: {
1276     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1277     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1278     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1279     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1280     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1281       Vals.push_back(*i);
1282     break;
1283   }
1284   case Instruction::Select:
1285     Code = bitc::FUNC_CODE_INST_VSELECT;
1286     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1287     pushValue(I.getOperand(2), InstID, Vals, VE);
1288     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1289     break;
1290   case Instruction::ExtractElement:
1291     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1292     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1293     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1294     break;
1295   case Instruction::InsertElement:
1296     Code = bitc::FUNC_CODE_INST_INSERTELT;
1297     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1298     pushValue(I.getOperand(1), InstID, Vals, VE);
1299     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1300     break;
1301   case Instruction::ShuffleVector:
1302     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1303     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1304     pushValue(I.getOperand(1), InstID, Vals, VE);
1305     pushValue(I.getOperand(2), InstID, Vals, VE);
1306     break;
1307   case Instruction::ICmp:
1308   case Instruction::FCmp:
1309     // compare returning Int1Ty or vector of Int1Ty
1310     Code = bitc::FUNC_CODE_INST_CMP2;
1311     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1312     pushValue(I.getOperand(1), InstID, Vals, VE);
1313     Vals.push_back(cast<CmpInst>(I).getPredicate());
1314     break;
1315
1316   case Instruction::Ret:
1317     {
1318       Code = bitc::FUNC_CODE_INST_RET;
1319       unsigned NumOperands = I.getNumOperands();
1320       if (NumOperands == 0)
1321         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1322       else if (NumOperands == 1) {
1323         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1324           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1325       } else {
1326         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1327           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1328       }
1329     }
1330     break;
1331   case Instruction::Br:
1332     {
1333       Code = bitc::FUNC_CODE_INST_BR;
1334       const BranchInst &II = cast<BranchInst>(I);
1335       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1336       if (II.isConditional()) {
1337         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1338         pushValue(II.getCondition(), InstID, Vals, VE);
1339       }
1340     }
1341     break;
1342   case Instruction::Switch:
1343     {
1344       Code = bitc::FUNC_CODE_INST_SWITCH;
1345       const SwitchInst &SI = cast<SwitchInst>(I);
1346       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1347       pushValue(SI.getCondition(), InstID, Vals, VE);
1348       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1349       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1350            i != e; ++i) {
1351         Vals.push_back(VE.getValueID(i.getCaseValue()));
1352         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1353       }
1354     }
1355     break;
1356   case Instruction::IndirectBr:
1357     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1358     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1359     // Encode the address operand as relative, but not the basic blocks.
1360     pushValue(I.getOperand(0), InstID, Vals, VE);
1361     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1362       Vals.push_back(VE.getValueID(I.getOperand(i)));
1363     break;
1364
1365   case Instruction::Invoke: {
1366     const InvokeInst *II = cast<InvokeInst>(&I);
1367     const Value *Callee(II->getCalledValue());
1368     PointerType *PTy = cast<PointerType>(Callee->getType());
1369     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1370     Code = bitc::FUNC_CODE_INST_INVOKE;
1371
1372     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1373     Vals.push_back(II->getCallingConv());
1374     Vals.push_back(VE.getValueID(II->getNormalDest()));
1375     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1376     PushValueAndType(Callee, InstID, Vals, VE);
1377
1378     // Emit value #'s for the fixed parameters.
1379     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1380       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1381
1382     // Emit type/value pairs for varargs params.
1383     if (FTy->isVarArg()) {
1384       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1385            i != e; ++i)
1386         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1387     }
1388     break;
1389   }
1390   case Instruction::Resume:
1391     Code = bitc::FUNC_CODE_INST_RESUME;
1392     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1393     break;
1394   case Instruction::Unreachable:
1395     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1396     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1397     break;
1398
1399   case Instruction::PHI: {
1400     const PHINode &PN = cast<PHINode>(I);
1401     Code = bitc::FUNC_CODE_INST_PHI;
1402     // With the newer instruction encoding, forward references could give
1403     // negative valued IDs.  This is most common for PHIs, so we use
1404     // signed VBRs.
1405     SmallVector<uint64_t, 128> Vals64;
1406     Vals64.push_back(VE.getTypeID(PN.getType()));
1407     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1408       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1409       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1410     }
1411     // Emit a Vals64 vector and exit.
1412     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1413     Vals64.clear();
1414     return;
1415   }
1416
1417   case Instruction::LandingPad: {
1418     const LandingPadInst &LP = cast<LandingPadInst>(I);
1419     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1420     Vals.push_back(VE.getTypeID(LP.getType()));
1421     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1422     Vals.push_back(LP.isCleanup());
1423     Vals.push_back(LP.getNumClauses());
1424     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1425       if (LP.isCatch(I))
1426         Vals.push_back(LandingPadInst::Catch);
1427       else
1428         Vals.push_back(LandingPadInst::Filter);
1429       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1430     }
1431     break;
1432   }
1433
1434   case Instruction::Alloca: {
1435     Code = bitc::FUNC_CODE_INST_ALLOCA;
1436     Vals.push_back(VE.getTypeID(I.getType()));
1437     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1438     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1439     const AllocaInst &AI = cast<AllocaInst>(I);
1440     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1441     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1442            "not enough bits for maximum alignment");
1443     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1444     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1445     Vals.push_back(AlignRecord);
1446     break;
1447   }
1448
1449   case Instruction::Load:
1450     if (cast<LoadInst>(I).isAtomic()) {
1451       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1452       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1453     } else {
1454       Code = bitc::FUNC_CODE_INST_LOAD;
1455       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1456         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1457     }
1458     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1459     Vals.push_back(cast<LoadInst>(I).isVolatile());
1460     if (cast<LoadInst>(I).isAtomic()) {
1461       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1462       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1463     }
1464     break;
1465   case Instruction::Store:
1466     if (cast<StoreInst>(I).isAtomic())
1467       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1468     else
1469       Code = bitc::FUNC_CODE_INST_STORE;
1470     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1471     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1472     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1473     Vals.push_back(cast<StoreInst>(I).isVolatile());
1474     if (cast<StoreInst>(I).isAtomic()) {
1475       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1476       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1477     }
1478     break;
1479   case Instruction::AtomicCmpXchg:
1480     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1481     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1482     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1483     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1484     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1485     Vals.push_back(GetEncodedOrdering(
1486                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1487     Vals.push_back(GetEncodedSynchScope(
1488                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1489     Vals.push_back(GetEncodedOrdering(
1490                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1491     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1492     break;
1493   case Instruction::AtomicRMW:
1494     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1495     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1496     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1497     Vals.push_back(GetEncodedRMWOperation(
1498                      cast<AtomicRMWInst>(I).getOperation()));
1499     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1500     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1501     Vals.push_back(GetEncodedSynchScope(
1502                      cast<AtomicRMWInst>(I).getSynchScope()));
1503     break;
1504   case Instruction::Fence:
1505     Code = bitc::FUNC_CODE_INST_FENCE;
1506     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1507     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1508     break;
1509   case Instruction::Call: {
1510     const CallInst &CI = cast<CallInst>(I);
1511     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1512     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1513
1514     Code = bitc::FUNC_CODE_INST_CALL;
1515
1516     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1517     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1518                    unsigned(CI.isMustTailCall()) << 14);
1519     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1520
1521     // Emit value #'s for the fixed parameters.
1522     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1523       // Check for labels (can happen with asm labels).
1524       if (FTy->getParamType(i)->isLabelTy())
1525         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1526       else
1527         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1528     }
1529
1530     // Emit type/value pairs for varargs params.
1531     if (FTy->isVarArg()) {
1532       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1533            i != e; ++i)
1534         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1535     }
1536     break;
1537   }
1538   case Instruction::VAArg:
1539     Code = bitc::FUNC_CODE_INST_VAARG;
1540     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1541     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1542     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1543     break;
1544   }
1545
1546   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1547   Vals.clear();
1548 }
1549
1550 // Emit names for globals/functions etc.
1551 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1552                                   const ValueEnumerator &VE,
1553                                   BitstreamWriter &Stream) {
1554   if (VST.empty()) return;
1555   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1556
1557   // FIXME: Set up the abbrev, we know how many values there are!
1558   // FIXME: We know if the type names can use 7-bit ascii.
1559   SmallVector<unsigned, 64> NameVals;
1560
1561   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1562        SI != SE; ++SI) {
1563
1564     const ValueName &Name = *SI;
1565
1566     // Figure out the encoding to use for the name.
1567     bool is7Bit = true;
1568     bool isChar6 = true;
1569     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1570          C != E; ++C) {
1571       if (isChar6)
1572         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1573       if ((unsigned char)*C & 128) {
1574         is7Bit = false;
1575         break;  // don't bother scanning the rest.
1576       }
1577     }
1578
1579     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1580
1581     // VST_ENTRY:   [valueid, namechar x N]
1582     // VST_BBENTRY: [bbid, namechar x N]
1583     unsigned Code;
1584     if (isa<BasicBlock>(SI->getValue())) {
1585       Code = bitc::VST_CODE_BBENTRY;
1586       if (isChar6)
1587         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1588     } else {
1589       Code = bitc::VST_CODE_ENTRY;
1590       if (isChar6)
1591         AbbrevToUse = VST_ENTRY_6_ABBREV;
1592       else if (is7Bit)
1593         AbbrevToUse = VST_ENTRY_7_ABBREV;
1594     }
1595
1596     NameVals.push_back(VE.getValueID(SI->getValue()));
1597     for (const char *P = Name.getKeyData(),
1598          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1599       NameVals.push_back((unsigned char)*P);
1600
1601     // Emit the finished record.
1602     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1603     NameVals.clear();
1604   }
1605   Stream.ExitBlock();
1606 }
1607
1608 /// WriteFunction - Emit a function body to the module stream.
1609 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1610                           BitstreamWriter &Stream) {
1611   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1612   VE.incorporateFunction(F);
1613
1614   SmallVector<unsigned, 64> Vals;
1615
1616   // Emit the number of basic blocks, so the reader can create them ahead of
1617   // time.
1618   Vals.push_back(VE.getBasicBlocks().size());
1619   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1620   Vals.clear();
1621
1622   // If there are function-local constants, emit them now.
1623   unsigned CstStart, CstEnd;
1624   VE.getFunctionConstantRange(CstStart, CstEnd);
1625   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1626
1627   // If there is function-local metadata, emit it now.
1628   WriteFunctionLocalMetadata(F, VE, Stream);
1629
1630   // Keep a running idea of what the instruction ID is.
1631   unsigned InstID = CstEnd;
1632
1633   bool NeedsMetadataAttachment = false;
1634
1635   DebugLoc LastDL;
1636
1637   // Finally, emit all the instructions, in order.
1638   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1639     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1640          I != E; ++I) {
1641       WriteInstruction(*I, InstID, VE, Stream, Vals);
1642
1643       if (!I->getType()->isVoidTy())
1644         ++InstID;
1645
1646       // If the instruction has metadata, write a metadata attachment later.
1647       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1648
1649       // If the instruction has a debug location, emit it.
1650       DebugLoc DL = I->getDebugLoc();
1651       if (DL.isUnknown()) {
1652         // nothing todo.
1653       } else if (DL == LastDL) {
1654         // Just repeat the same debug loc as last time.
1655         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1656       } else {
1657         MDNode *Scope, *IA;
1658         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1659
1660         Vals.push_back(DL.getLine());
1661         Vals.push_back(DL.getCol());
1662         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1663         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1664         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1665         Vals.clear();
1666
1667         LastDL = DL;
1668       }
1669     }
1670
1671   // Emit names for all the instructions etc.
1672   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1673
1674   if (NeedsMetadataAttachment)
1675     WriteMetadataAttachment(F, VE, Stream);
1676   VE.purgeFunction();
1677   Stream.ExitBlock();
1678 }
1679
1680 // Emit blockinfo, which defines the standard abbreviations etc.
1681 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1682   // We only want to emit block info records for blocks that have multiple
1683   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1684   // Other blocks can define their abbrevs inline.
1685   Stream.EnterBlockInfoBlock(2);
1686
1687   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1688     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1689     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1690     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1691     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1692     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1693     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1694                                    Abbv) != VST_ENTRY_8_ABBREV)
1695       llvm_unreachable("Unexpected abbrev ordering!");
1696   }
1697
1698   { // 7-bit fixed width VST_ENTRY strings.
1699     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1700     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1701     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1702     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1703     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1704     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1705                                    Abbv) != VST_ENTRY_7_ABBREV)
1706       llvm_unreachable("Unexpected abbrev ordering!");
1707   }
1708   { // 6-bit char6 VST_ENTRY strings.
1709     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1710     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1711     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1712     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1713     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1714     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1715                                    Abbv) != VST_ENTRY_6_ABBREV)
1716       llvm_unreachable("Unexpected abbrev ordering!");
1717   }
1718   { // 6-bit char6 VST_BBENTRY strings.
1719     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1720     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1721     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1722     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1723     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1724     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1725                                    Abbv) != VST_BBENTRY_6_ABBREV)
1726       llvm_unreachable("Unexpected abbrev ordering!");
1727   }
1728
1729
1730
1731   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1732     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1733     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1734     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1735                               Log2_32_Ceil(VE.getTypes().size()+1)));
1736     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1737                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1738       llvm_unreachable("Unexpected abbrev ordering!");
1739   }
1740
1741   { // INTEGER abbrev for CONSTANTS_BLOCK.
1742     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1743     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1744     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1745     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1746                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1747       llvm_unreachable("Unexpected abbrev ordering!");
1748   }
1749
1750   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1751     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1752     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1753     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1754     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1755                               Log2_32_Ceil(VE.getTypes().size()+1)));
1756     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1757
1758     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1759                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1760       llvm_unreachable("Unexpected abbrev ordering!");
1761   }
1762   { // NULL abbrev for CONSTANTS_BLOCK.
1763     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1764     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1765     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1766                                    Abbv) != CONSTANTS_NULL_Abbrev)
1767       llvm_unreachable("Unexpected abbrev ordering!");
1768   }
1769
1770   // FIXME: This should only use space for first class types!
1771
1772   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1773     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1774     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1775     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1776     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1777     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1778     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1779                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1780       llvm_unreachable("Unexpected abbrev ordering!");
1781   }
1782   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1783     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1784     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1787     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1788     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1789                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1790       llvm_unreachable("Unexpected abbrev ordering!");
1791   }
1792   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1793     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1794     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1799     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1800                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1801       llvm_unreachable("Unexpected abbrev ordering!");
1802   }
1803   { // INST_CAST abbrev for FUNCTION_BLOCK.
1804     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1805     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1807     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1808                               Log2_32_Ceil(VE.getTypes().size()+1)));
1809     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1810     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1811                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1812       llvm_unreachable("Unexpected abbrev ordering!");
1813   }
1814
1815   { // INST_RET abbrev for FUNCTION_BLOCK.
1816     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1817     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1818     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1819                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1820       llvm_unreachable("Unexpected abbrev ordering!");
1821   }
1822   { // INST_RET abbrev for FUNCTION_BLOCK.
1823     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1824     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1825     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1826     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1827                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1828       llvm_unreachable("Unexpected abbrev ordering!");
1829   }
1830   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1831     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1832     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1833     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1834                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1835       llvm_unreachable("Unexpected abbrev ordering!");
1836   }
1837
1838   Stream.ExitBlock();
1839 }
1840
1841 // Sort the Users based on the order in which the reader parses the bitcode
1842 // file.
1843 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1844   // TODO: Implement.
1845   return true;
1846 }
1847
1848 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1849                          BitstreamWriter &Stream) {
1850
1851   // One or zero uses can't get out of order.
1852   if (V->use_empty() || V->hasNUses(1))
1853     return;
1854
1855   // Make a copy of the in-memory use-list for sorting.
1856   SmallVector<const User*, 8> UserList(V->user_begin(), V->user_end());
1857
1858   // Sort the copy based on the order read by the BitcodeReader.
1859   std::sort(UserList.begin(), UserList.end(), bitcodereader_order);
1860
1861   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1862   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1863
1864   // TODO: Emit the USELIST_CODE_ENTRYs.
1865 }
1866
1867 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1868                                  BitstreamWriter &Stream) {
1869   VE.incorporateFunction(*F);
1870
1871   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1872        AI != AE; ++AI)
1873     WriteUseList(AI, VE, Stream);
1874   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1875        ++BB) {
1876     WriteUseList(BB, VE, Stream);
1877     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1878          ++II) {
1879       WriteUseList(II, VE, Stream);
1880       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1881            OI != E; ++OI) {
1882         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1883             isa<InlineAsm>(*OI))
1884           WriteUseList(*OI, VE, Stream);
1885       }
1886     }
1887   }
1888   VE.purgeFunction();
1889 }
1890
1891 // Emit use-lists.
1892 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1893                                 BitstreamWriter &Stream) {
1894   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1895
1896   // XXX: this modifies the module, but in a way that should never change the
1897   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1898   // contain entries in the use_list that do not exist in the Module and are
1899   // not stored in the .bc file.
1900   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1901        I != E; ++I)
1902     I->removeDeadConstantUsers();
1903
1904   // Write the global variables.
1905   for (Module::const_global_iterator GI = M->global_begin(),
1906          GE = M->global_end(); GI != GE; ++GI) {
1907     WriteUseList(GI, VE, Stream);
1908
1909     // Write the global variable initializers.
1910     if (GI->hasInitializer())
1911       WriteUseList(GI->getInitializer(), VE, Stream);
1912   }
1913
1914   // Write the functions.
1915   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1916     WriteUseList(FI, VE, Stream);
1917     if (!FI->isDeclaration())
1918       WriteFunctionUseList(FI, VE, Stream);
1919     if (FI->hasPrefixData())
1920       WriteUseList(FI->getPrefixData(), VE, Stream);
1921   }
1922
1923   // Write the aliases.
1924   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1925        AI != AE; ++AI) {
1926     WriteUseList(AI, VE, Stream);
1927     WriteUseList(AI->getAliasee(), VE, Stream);
1928   }
1929
1930   Stream.ExitBlock();
1931 }
1932
1933 /// WriteModule - Emit the specified module to the bitstream.
1934 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1935   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1936
1937   SmallVector<unsigned, 1> Vals;
1938   unsigned CurVersion = 1;
1939   Vals.push_back(CurVersion);
1940   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1941
1942   // Analyze the module, enumerating globals, functions, etc.
1943   ValueEnumerator VE(M);
1944
1945   // Emit blockinfo, which defines the standard abbreviations etc.
1946   WriteBlockInfo(VE, Stream);
1947
1948   // Emit information about attribute groups.
1949   WriteAttributeGroupTable(VE, Stream);
1950
1951   // Emit information about parameter attributes.
1952   WriteAttributeTable(VE, Stream);
1953
1954   // Emit information describing all of the types in the module.
1955   WriteTypeTable(VE, Stream);
1956
1957   writeComdats(VE, Stream);
1958
1959   // Emit top-level description of module, including target triple, inline asm,
1960   // descriptors for global variables, and function prototype info.
1961   WriteModuleInfo(M, VE, Stream);
1962
1963   // Emit constants.
1964   WriteModuleConstants(VE, Stream);
1965
1966   // Emit metadata.
1967   WriteModuleMetadata(M, VE, Stream);
1968
1969   // Emit metadata.
1970   WriteModuleMetadataStore(M, Stream);
1971
1972   // Emit names for globals/functions etc.
1973   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1974
1975   // Emit use-lists.
1976   if (EnablePreserveUseListOrdering)
1977     WriteModuleUseLists(M, VE, Stream);
1978
1979   // Emit function bodies.
1980   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1981     if (!F->isDeclaration())
1982       WriteFunction(*F, VE, Stream);
1983
1984   Stream.ExitBlock();
1985 }
1986
1987 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1988 /// header and trailer to make it compatible with the system archiver.  To do
1989 /// this we emit the following header, and then emit a trailer that pads the
1990 /// file out to be a multiple of 16 bytes.
1991 ///
1992 /// struct bc_header {
1993 ///   uint32_t Magic;         // 0x0B17C0DE
1994 ///   uint32_t Version;       // Version, currently always 0.
1995 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1996 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1997 ///   uint32_t CPUType;       // CPU specifier.
1998 ///   ... potentially more later ...
1999 /// };
2000 enum {
2001   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2002   DarwinBCHeaderSize = 5*4
2003 };
2004
2005 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2006                                uint32_t &Position) {
2007   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2008   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2009   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2010   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2011   Position += 4;
2012 }
2013
2014 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2015                                          const Triple &TT) {
2016   unsigned CPUType = ~0U;
2017
2018   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2019   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2020   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2021   // specific constants here because they are implicitly part of the Darwin ABI.
2022   enum {
2023     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2024     DARWIN_CPU_TYPE_X86        = 7,
2025     DARWIN_CPU_TYPE_ARM        = 12,
2026     DARWIN_CPU_TYPE_POWERPC    = 18
2027   };
2028
2029   Triple::ArchType Arch = TT.getArch();
2030   if (Arch == Triple::x86_64)
2031     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2032   else if (Arch == Triple::x86)
2033     CPUType = DARWIN_CPU_TYPE_X86;
2034   else if (Arch == Triple::ppc)
2035     CPUType = DARWIN_CPU_TYPE_POWERPC;
2036   else if (Arch == Triple::ppc64)
2037     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2038   else if (Arch == Triple::arm || Arch == Triple::thumb)
2039     CPUType = DARWIN_CPU_TYPE_ARM;
2040
2041   // Traditional Bitcode starts after header.
2042   assert(Buffer.size() >= DarwinBCHeaderSize &&
2043          "Expected header size to be reserved");
2044   unsigned BCOffset = DarwinBCHeaderSize;
2045   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2046
2047   // Write the magic and version.
2048   unsigned Position = 0;
2049   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2050   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2051   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2052   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2053   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2054
2055   // If the file is not a multiple of 16 bytes, insert dummy padding.
2056   while (Buffer.size() & 15)
2057     Buffer.push_back(0);
2058 }
2059
2060 /// WriteBitcodeToFile - Write the specified module to the specified output
2061 /// stream.
2062 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2063   SmallVector<char, 0> Buffer;
2064   Buffer.reserve(256*1024);
2065
2066   // If this is darwin or another generic macho target, reserve space for the
2067   // header.
2068   Triple TT(M->getTargetTriple());
2069   if (TT.isOSDarwin())
2070     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2071
2072   // Emit the module into the buffer.
2073   {
2074     BitstreamWriter Stream(Buffer);
2075
2076     // Emit the file header.
2077     Stream.Emit((unsigned)'B', 8);
2078     Stream.Emit((unsigned)'C', 8);
2079     Stream.Emit(0x0, 4);
2080     Stream.Emit(0xC, 4);
2081     Stream.Emit(0xE, 4);
2082     Stream.Emit(0xD, 4);
2083
2084     // Emit the module.
2085     WriteModule(M, Stream);
2086   }
2087
2088   if (TT.isOSDarwin())
2089     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2090
2091   // Write the generated bitstream to "Out".
2092   Out.write((char*)&Buffer.front(), Buffer.size());
2093 }