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