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/DebugInfoMetadata.h"
  21 #include "llvm/IR/DerivedTypes.h"
  22 #include "llvm/IR/InlineAsm.h"
  23 #include "llvm/IR/Instructions.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/IR/Operator.h"
  26 #include "llvm/IR/UseListOrder.h"
  27 #include "llvm/IR/ValueSymbolTable.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/MathExtras.h"
  31 #include "llvm/Support/Program.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 #include <cctype>
  34 #include <map>
  35 using namespace llvm;
  36
  37 /// These are manifest constants used by the bitcode writer. They do not need to
  38 /// be kept in sync with the reader, but need to be consistent within this file.
  39 enum {
  40   // VALUE_SYMTAB_BLOCK abbrev id's.
  41   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  42   VST_ENTRY_7_ABBREV,
  43   VST_ENTRY_6_ABBREV,
  44   VST_BBENTRY_6_ABBREV,
  45
  46   // CONSTANTS_BLOCK abbrev id's.
  47   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   CONSTANTS_INTEGER_ABBREV,
  49   CONSTANTS_CE_CAST_Abbrev,
  50   CONSTANTS_NULL_Abbrev,
  51
  52   // FUNCTION_BLOCK abbrev id's.
  53   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   FUNCTION_INST_BINOP_ABBREV,
  55   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  56   FUNCTION_INST_CAST_ABBREV,
  57   FUNCTION_INST_RET_VOID_ABBREV,
  58   FUNCTION_INST_RET_VAL_ABBREV,
  59   FUNCTION_INST_UNREACHABLE_ABBREV
  60 };
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  78   }
  79 }
  80
  81 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  82   switch (Opcode) {
  83   default: llvm_unreachable("Unknown binary instruction!");
  84   case Instruction::Add:
  85   case Instruction::FAdd: return bitc::BINOP_ADD;
  86   case Instruction::Sub:
  87   case Instruction::FSub: return bitc::BINOP_SUB;
  88   case Instruction::Mul:
  89   case Instruction::FMul: return bitc::BINOP_MUL;
  90   case Instruction::UDiv: return bitc::BINOP_UDIV;
  91   case Instruction::FDiv:
  92   case Instruction::SDiv: return bitc::BINOP_SDIV;
  93   case Instruction::URem: return bitc::BINOP_UREM;
  94   case Instruction::FRem:
  95   case Instruction::SRem: return bitc::BINOP_SREM;
  96   case Instruction::Shl:  return bitc::BINOP_SHL;
  97   case Instruction::LShr: return bitc::BINOP_LSHR;
  98   case Instruction::AShr: return bitc::BINOP_ASHR;
  99   case Instruction::And:  return bitc::BINOP_AND;
 100   case Instruction::Or:   return bitc::BINOP_OR;
 101   case Instruction::Xor:  return bitc::BINOP_XOR;
 102   }
 103 }
 104
 105 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 106   switch (Op) {
 107   default: llvm_unreachable("Unknown RMW operation!");
 108   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 109   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 110   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 111   case AtomicRMWInst::And: return bitc::RMW_AND;
 112   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 113   case AtomicRMWInst::Or: return bitc::RMW_OR;
 114   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 115   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 116   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 117   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 118   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 119   }
 120 }
 121
 122 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 123   switch (Ordering) {
 124   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 125   case Unordered: return bitc::ORDERING_UNORDERED;
 126   case Monotonic: return bitc::ORDERING_MONOTONIC;
 127   case Acquire: return bitc::ORDERING_ACQUIRE;
 128   case Release: return bitc::ORDERING_RELEASE;
 129   case AcquireRelease: return bitc::ORDERING_ACQREL;
 130   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 131   }
 132   llvm_unreachable("Invalid ordering");
 133 }
 134
 135 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 136   switch (SynchScope) {
 137   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 138   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 139   }
 140   llvm_unreachable("Invalid synch scope");
 141 }
 142
 143 static void WriteStringRecord(unsigned Code, StringRef Str,
 144                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 145   SmallVector<unsigned, 64> Vals;
 146
 147   // Code: [strchar x N]
 148   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 149     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 150       AbbrevToUse = 0;
 151     Vals.push_back(Str[i]);
 152   }
 153
 154   // Emit the finished record.
 155   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 156 }
 157
 158 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 159   switch (Kind) {
 160   case Attribute::Alignment:
 161     return bitc::ATTR_KIND_ALIGNMENT;
 162   case Attribute::AlwaysInline:
 163     return bitc::ATTR_KIND_ALWAYS_INLINE;
 164   case Attribute::Builtin:
 165     return bitc::ATTR_KIND_BUILTIN;
 166   case Attribute::ByVal:
 167     return bitc::ATTR_KIND_BY_VAL;
 168   case Attribute::InAlloca:
 169     return bitc::ATTR_KIND_IN_ALLOCA;
 170   case Attribute::Cold:
 171     return bitc::ATTR_KIND_COLD;
 172   case Attribute::InlineHint:
 173     return bitc::ATTR_KIND_INLINE_HINT;
 174   case Attribute::InReg:
 175     return bitc::ATTR_KIND_IN_REG;
 176   case Attribute::JumpTable:
 177     return bitc::ATTR_KIND_JUMP_TABLE;
 178   case Attribute::MinSize:
 179     return bitc::ATTR_KIND_MIN_SIZE;
 180   case Attribute::Naked:
 181     return bitc::ATTR_KIND_NAKED;
 182   case Attribute::Nest:
 183     return bitc::ATTR_KIND_NEST;
 184   case Attribute::NoAlias:
 185     return bitc::ATTR_KIND_NO_ALIAS;
 186   case Attribute::NoBuiltin:
 187     return bitc::ATTR_KIND_NO_BUILTIN;
 188   case Attribute::NoCapture:
 189     return bitc::ATTR_KIND_NO_CAPTURE;
 190   case Attribute::NoDuplicate:
 191     return bitc::ATTR_KIND_NO_DUPLICATE;
 192   case Attribute::NoImplicitFloat:
 193     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 194   case Attribute::NoInline:
 195     return bitc::ATTR_KIND_NO_INLINE;
 196   case Attribute::NonLazyBind:
 197     return bitc::ATTR_KIND_NON_LAZY_BIND;
 198   case Attribute::NonNull:
 199     return bitc::ATTR_KIND_NON_NULL;
 200   case Attribute::Dereferenceable:
 201     return bitc::ATTR_KIND_DEREFERENCEABLE;
 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.isIntAttribute()) {
 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:
 482     return 0;
 483   case GlobalValue::WeakAnyLinkage:
 484     return 16;
 485   case GlobalValue::AppendingLinkage:
 486     return 2;
 487   case GlobalValue::InternalLinkage:
 488     return 3;
 489   case GlobalValue::LinkOnceAnyLinkage:
 490     return 18;
 491   case GlobalValue::ExternalWeakLinkage:
 492     return 7;
 493   case GlobalValue::CommonLinkage:
 494     return 8;
 495   case GlobalValue::PrivateLinkage:
 496     return 9;
 497   case GlobalValue::WeakODRLinkage:
 498     return 17;
 499   case GlobalValue::LinkOnceODRLinkage:
 500     return 19;
 501   case GlobalValue::AvailableExternallyLinkage:
 502     return 12;
 503   }
 504   llvm_unreachable("Invalid linkage");
 505 }
 506
 507 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 508   switch (GV.getVisibility()) {
 509   case GlobalValue::DefaultVisibility:   return 0;
 510   case GlobalValue::HiddenVisibility:    return 1;
 511   case GlobalValue::ProtectedVisibility: return 2;
 512   }
 513   llvm_unreachable("Invalid visibility");
 514 }
 515
 516 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 517   switch (GV.getDLLStorageClass()) {
 518   case GlobalValue::DefaultStorageClass:   return 0;
 519   case GlobalValue::DLLImportStorageClass: return 1;
 520   case GlobalValue::DLLExportStorageClass: return 2;
 521   }
 522   llvm_unreachable("Invalid DLL storage class");
 523 }
 524
 525 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 526   switch (GV.getThreadLocalMode()) {
 527     case GlobalVariable::NotThreadLocal:         return 0;
 528     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 529     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 530     case GlobalVariable::InitialExecTLSModel:    return 3;
 531     case GlobalVariable::LocalExecTLSModel:      return 4;
 532   }
 533   llvm_unreachable("Invalid TLS model");
 534 }
 535
 536 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 537   switch (C.getSelectionKind()) {
 538   case Comdat::Any:
 539     return bitc::COMDAT_SELECTION_KIND_ANY;
 540   case Comdat::ExactMatch:
 541     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 542   case Comdat::Largest:
 543     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 544   case Comdat::NoDuplicates:
 545     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 546   case Comdat::SameSize:
 547     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 548   }
 549   llvm_unreachable("Invalid selection kind");
 550 }
 551
 552 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 553   SmallVector<uint16_t, 64> Vals;
 554   for (const Comdat *C : VE.getComdats()) {
 555     // COMDAT: [selection_kind, name]
 556     Vals.push_back(getEncodedComdatSelectionKind(*C));
 557     size_t Size = C->getName().size();
 558     assert(isUInt<16>(Size));
 559     Vals.push_back(Size);
 560     for (char Chr : C->getName())
 561       Vals.push_back((unsigned char)Chr);
 562     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 563     Vals.clear();
 564   }
 565 }
 566
 567 // Emit top-level description of module, including target triple, inline asm,
 568 // descriptors for global variables, and function prototype info.
 569 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 570                             BitstreamWriter &Stream) {
 571   // Emit various pieces of data attached to a module.
 572   if (!M->getTargetTriple().empty())
 573     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 574                       0/*TODO*/, Stream);
 575   const std::string &DL = M->getDataLayoutStr();
 576   if (!DL.empty())
 577     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 578   if (!M->getModuleInlineAsm().empty())
 579     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 580                       0/*TODO*/, Stream);
 581
 582   // Emit information about sections and GC, computing how many there are. Also
 583   // compute the maximum alignment value.
 584   std::map<std::string, unsigned> SectionMap;
 585   std::map<std::string, unsigned> GCMap;
 586   unsigned MaxAlignment = 0;
 587   unsigned MaxGlobalType = 0;
 588   for (const GlobalValue &GV : M->globals()) {
 589     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 590     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 591     if (GV.hasSection()) {
 592       // Give section names unique ID's.
 593       unsigned &Entry = SectionMap[GV.getSection()];
 594       if (!Entry) {
 595         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 596                           0/*TODO*/, Stream);
 597         Entry = SectionMap.size();
 598       }
 599     }
 600   }
 601   for (const Function &F : *M) {
 602     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 603     if (F.hasSection()) {
 604       // Give section names unique ID's.
 605       unsigned &Entry = SectionMap[F.getSection()];
 606       if (!Entry) {
 607         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 608                           0/*TODO*/, Stream);
 609         Entry = SectionMap.size();
 610       }
 611     }
 612     if (F.hasGC()) {
 613       // Same for GC names.
 614       unsigned &Entry = GCMap[F.getGC()];
 615       if (!Entry) {
 616         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 617                           0/*TODO*/, Stream);
 618         Entry = GCMap.size();
 619       }
 620     }
 621   }
 622
 623   // Emit abbrev for globals, now that we know # sections and max alignment.
 624   unsigned SimpleGVarAbbrev = 0;
 625   if (!M->global_empty()) {
 626     // Add an abbrev for common globals with no visibility or thread localness.
 627     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 628     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 629     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 630                               Log2_32_Ceil(MaxGlobalType+1)));
 631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5));      // Linkage.
 634     if (MaxAlignment == 0)                                      // Alignment.
 635       Abbv->Add(BitCodeAbbrevOp(0));
 636     else {
 637       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 638       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 639                                Log2_32_Ceil(MaxEncAlignment+1)));
 640     }
 641     if (SectionMap.empty())                                    // Section.
 642       Abbv->Add(BitCodeAbbrevOp(0));
 643     else
 644       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 645                                Log2_32_Ceil(SectionMap.size()+1)));
 646     // Don't bother emitting vis + thread local.
 647     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 648   }
 649
 650   // Emit the global variable information.
 651   SmallVector<unsigned, 64> Vals;
 652   for (const GlobalVariable &GV : M->globals()) {
 653     unsigned AbbrevToUse = 0;
 654
 655     // GLOBALVAR: [type, isconst, initid,
 656     //             linkage, alignment, section, visibility, threadlocal,
 657     //             unnamed_addr, externally_initialized, dllstorageclass,
 658     //             comdat]
 659     Vals.push_back(VE.getTypeID(GV.getType()));
 660     Vals.push_back(GV.isConstant());
 661     Vals.push_back(GV.isDeclaration() ? 0 :
 662                    (VE.getValueID(GV.getInitializer()) + 1));
 663     Vals.push_back(getEncodedLinkage(GV));
 664     Vals.push_back(Log2_32(GV.getAlignment())+1);
 665     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 666     if (GV.isThreadLocal() ||
 667         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 668         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 669         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 670         GV.hasComdat()) {
 671       Vals.push_back(getEncodedVisibility(GV));
 672       Vals.push_back(getEncodedThreadLocalMode(GV));
 673       Vals.push_back(GV.hasUnnamedAddr());
 674       Vals.push_back(GV.isExternallyInitialized());
 675       Vals.push_back(getEncodedDLLStorageClass(GV));
 676       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 677     } else {
 678       AbbrevToUse = SimpleGVarAbbrev;
 679     }
 680
 681     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 682     Vals.clear();
 683   }
 684
 685   // Emit the function proto information.
 686   for (const Function &F : *M) {
 687     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 688     //             section, visibility, gc, unnamed_addr, prologuedata,
 689     //             dllstorageclass, comdat, prefixdata]
 690     Vals.push_back(VE.getTypeID(F.getType()));
 691     Vals.push_back(F.getCallingConv());
 692     Vals.push_back(F.isDeclaration());
 693     Vals.push_back(getEncodedLinkage(F));
 694     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 695     Vals.push_back(Log2_32(F.getAlignment())+1);
 696     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 697     Vals.push_back(getEncodedVisibility(F));
 698     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 699     Vals.push_back(F.hasUnnamedAddr());
 700     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 701                                        : 0);
 702     Vals.push_back(getEncodedDLLStorageClass(F));
 703     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 704     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 705                                      : 0);
 706
 707     unsigned AbbrevToUse = 0;
 708     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 709     Vals.clear();
 710   }
 711
 712   // Emit the alias information.
 713   for (const GlobalAlias &A : M->aliases()) {
 714     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 715     Vals.push_back(VE.getTypeID(A.getType()));
 716     Vals.push_back(VE.getValueID(A.getAliasee()));
 717     Vals.push_back(getEncodedLinkage(A));
 718     Vals.push_back(getEncodedVisibility(A));
 719     Vals.push_back(getEncodedDLLStorageClass(A));
 720     Vals.push_back(getEncodedThreadLocalMode(A));
 721     Vals.push_back(A.hasUnnamedAddr());
 722     unsigned AbbrevToUse = 0;
 723     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 724     Vals.clear();
 725   }
 726 }
 727
 728 static uint64_t GetOptimizationFlags(const Value *V) {
 729   uint64_t Flags = 0;
 730
 731   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 732     if (OBO->hasNoSignedWrap())
 733       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 734     if (OBO->hasNoUnsignedWrap())
 735       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 736   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 737     if (PEO->isExact())
 738       Flags |= 1 << bitc::PEO_EXACT;
 739   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 740     if (FPMO->hasUnsafeAlgebra())
 741       Flags |= FastMathFlags::UnsafeAlgebra;
 742     if (FPMO->hasNoNaNs())
 743       Flags |= FastMathFlags::NoNaNs;
 744     if (FPMO->hasNoInfs())
 745       Flags |= FastMathFlags::NoInfs;
 746     if (FPMO->hasNoSignedZeros())
 747       Flags |= FastMathFlags::NoSignedZeros;
 748     if (FPMO->hasAllowReciprocal())
 749       Flags |= FastMathFlags::AllowReciprocal;
 750   }
 751
 752   return Flags;
 753 }
 754
 755 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 756                                  const ValueEnumerator &VE,
 757                                  BitstreamWriter &Stream,
 758                                  SmallVectorImpl<uint64_t> &Record) {
 759   // Mimic an MDNode with a value as one operand.
 760   Value *V = MD->getValue();
 761   Record.push_back(VE.getTypeID(V->getType()));
 762   Record.push_back(VE.getValueID(V));
 763   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 764   Record.clear();
 765 }
 766
 767 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 768                          BitstreamWriter &Stream,
 769                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 770   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 771     Metadata *MD = N->getOperand(i);
 772     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 773            "Unexpected function-local metadata");
 774     Record.push_back(VE.getMetadataOrNullID(MD));
 775   }
 776   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 777                                     : bitc::METADATA_NODE,
 778                     Record, Abbrev);
 779   Record.clear();
 780 }
 781
 782 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 783                             BitstreamWriter &Stream,
 784                             SmallVectorImpl<uint64_t> &Record,
 785                             unsigned Abbrev) {
 786   Record.push_back(N->isDistinct());
 787   Record.push_back(N->getLine());
 788   Record.push_back(N->getColumn());
 789   Record.push_back(VE.getMetadataID(N->getScope()));
 790   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 791
 792   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 793   Record.clear();
 794 }
 795
 796 static void WriteGenericDebugNode(const GenericDebugNode *N,
 797                                   const ValueEnumerator &VE,
 798                                   BitstreamWriter &Stream,
 799                                   SmallVectorImpl<uint64_t> &Record,
 800                                   unsigned Abbrev) {
 801   Record.push_back(N->isDistinct());
 802   Record.push_back(N->getTag());
 803   Record.push_back(0); // Per-tag version field; unused for now.
 804
 805   for (auto &I : N->operands())
 806     Record.push_back(VE.getMetadataOrNullID(I));
 807
 808   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 809   Record.clear();
 810 }
 811
 812 static uint64_t rotateSign(int64_t I) {
 813   uint64_t U = I;
 814   return I < 0 ? ~(U << 1) : U << 1;
 815 }
 816
 817 static void WriteMDSubrange(const MDSubrange *N, const ValueEnumerator &,
 818                             BitstreamWriter &Stream,
 819                             SmallVectorImpl<uint64_t> &Record,
 820                             unsigned Abbrev) {
 821   Record.push_back(N->isDistinct());
 822   Record.push_back(N->getCount());
 823   Record.push_back(rotateSign(N->getLo()));
 824
 825   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 826   Record.clear();
 827 }
 828
 829 static void WriteMDEnumerator(const MDEnumerator *N, const ValueEnumerator &VE,
 830                               BitstreamWriter &Stream,
 831                               SmallVectorImpl<uint64_t> &Record,
 832                               unsigned Abbrev) {
 833   Record.push_back(N->isDistinct());
 834   Record.push_back(rotateSign(N->getValue()));
 835   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 836
 837   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 838   Record.clear();
 839 }
 840
 841 static void WriteMDBasicType(const MDBasicType *N, const ValueEnumerator &VE,
 842                              BitstreamWriter &Stream,
 843                              SmallVectorImpl<uint64_t> &Record,
 844                              unsigned Abbrev) {
 845   Record.push_back(N->isDistinct());
 846   Record.push_back(N->getTag());
 847   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 848   Record.push_back(N->getSizeInBits());
 849   Record.push_back(N->getAlignInBits());
 850   Record.push_back(N->getEncoding());
 851
 852   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 853   Record.clear();
 854 }
 855
 856 static void WriteMDDerivedType(const MDDerivedType *N,
 857                                const ValueEnumerator &VE,
 858                                BitstreamWriter &Stream,
 859                                SmallVectorImpl<uint64_t> &Record,
 860                                unsigned Abbrev) {
 861   Record.push_back(N->isDistinct());
 862   Record.push_back(N->getTag());
 863   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 864   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 865   Record.push_back(N->getLine());
 866   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 867   Record.push_back(VE.getMetadataID(N->getBaseType()));
 868   Record.push_back(N->getSizeInBits());
 869   Record.push_back(N->getAlignInBits());
 870   Record.push_back(N->getOffsetInBits());
 871   Record.push_back(N->getFlags());
 872   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 873
 874   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 875   Record.clear();
 876 }
 877
 878 static void WriteMDCompositeType(const MDCompositeType *N,
 879                                  const ValueEnumerator &VE,
 880                                  BitstreamWriter &Stream,
 881                                  SmallVectorImpl<uint64_t> &Record,
 882                                  unsigned Abbrev) {
 883   Record.push_back(N->isDistinct());
 884   Record.push_back(N->getTag());
 885   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 886   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 887   Record.push_back(N->getLine());
 888   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 889   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 890   Record.push_back(N->getSizeInBits());
 891   Record.push_back(N->getAlignInBits());
 892   Record.push_back(N->getOffsetInBits());
 893   Record.push_back(N->getFlags());
 894   Record.push_back(VE.getMetadataOrNullID(N->getElements()));
 895   Record.push_back(N->getRuntimeLang());
 896   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 897   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
 898   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 899
 900   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 901   Record.clear();
 902 }
 903
 904 static void WriteMDSubroutineType(const MDSubroutineType *N,
 905                                   const ValueEnumerator &VE,
 906                                   BitstreamWriter &Stream,
 907                                   SmallVectorImpl<uint64_t> &Record,
 908                                   unsigned Abbrev) {
 909   Record.push_back(N->isDistinct());
 910   Record.push_back(N->getFlags());
 911   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray()));
 912
 913   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 914   Record.clear();
 915 }
 916
 917 static void WriteMDFile(const MDFile *N, const ValueEnumerator &VE,
 918                         BitstreamWriter &Stream,
 919                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 920   Record.push_back(N->isDistinct());
 921   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 922   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 923
 924   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 925   Record.clear();
 926 }
 927
 928 static void WriteMDCompileUnit(const MDCompileUnit *N,
 929                                const ValueEnumerator &VE,
 930                                BitstreamWriter &Stream,
 931                                SmallVectorImpl<uint64_t> &Record,
 932                                unsigned Abbrev) {
 933   Record.push_back(N->isDistinct());
 934   Record.push_back(N->getSourceLanguage());
 935   Record.push_back(VE.getMetadataID(N->getFile()));
 936   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 937   Record.push_back(N->isOptimized());
 938   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 939   Record.push_back(N->getRuntimeVersion());
 940   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 941   Record.push_back(N->getEmissionKind());
 942   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes()));
 943   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes()));
 944   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms()));
 945   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables()));
 946   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities()));
 947
 948   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 949   Record.clear();
 950 }
 951
 952 static void WriteMDSubprogram(const MDSubprogram *N,
 953                                const ValueEnumerator &VE,
 954                                BitstreamWriter &Stream,
 955                                SmallVectorImpl<uint64_t> &Record,
 956                                unsigned Abbrev) {
 957   Record.push_back(N->isDistinct());
 958   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 959   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 960   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 961   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 962   Record.push_back(N->getLine());
 963   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 964   Record.push_back(N->isLocalToUnit());
 965   Record.push_back(N->isDefinition());
 966   Record.push_back(N->getScopeLine());
 967   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 968   Record.push_back(N->getVirtuality());
 969   Record.push_back(N->getVirtualIndex());
 970   Record.push_back(N->getFlags());
 971   Record.push_back(N->isOptimized());
 972   Record.push_back(VE.getMetadataOrNullID(N->getFunction()));
 973   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
 974   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 975   Record.push_back(VE.getMetadataOrNullID(N->getVariables()));
 976
 977   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 978   Record.clear();
 979 }
 980
 981 static void WriteMDLexicalBlock(const MDLexicalBlock *N,
 982                                const ValueEnumerator &VE,
 983                                BitstreamWriter &Stream,
 984                                SmallVectorImpl<uint64_t> &Record,
 985                                unsigned Abbrev) {
 986   Record.push_back(N->isDistinct());
 987   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 988   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 989   Record.push_back(N->getLine());
 990   Record.push_back(N->getColumn());
 991
 992   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
 993   Record.clear();
 994 }
 995
 996 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *N,
 997                                     const ValueEnumerator &VE,
 998                                     BitstreamWriter &Stream,
 999                                     SmallVectorImpl<uint64_t> &Record,
1000                                     unsigned Abbrev) {
1001   Record.push_back(N->isDistinct());
1002   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1003   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1004   Record.push_back(N->getDiscriminator());
1005
1006   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1007   Record.clear();
1008 }
1009
1010 static void WriteMDNamespace(const MDNamespace *N, const ValueEnumerator &VE,
1011                              BitstreamWriter &Stream,
1012                              SmallVectorImpl<uint64_t> &Record,
1013                              unsigned Abbrev) {
1014   Record.push_back(N->isDistinct());
1015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1016   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1017   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1018   Record.push_back(N->getLine());
1019
1020   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1021   Record.clear();
1022 }
1023
1024 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *N,
1025                                          const ValueEnumerator &VE,
1026                                          BitstreamWriter &Stream,
1027                                          SmallVectorImpl<uint64_t> &Record,
1028                                          unsigned Abbrev) {
1029   Record.push_back(N->isDistinct());
1030   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1031   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1032   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1033
1034   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1035   Record.clear();
1036 }
1037
1038 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *N,
1039                                           const ValueEnumerator &VE,
1040                                           BitstreamWriter &Stream,
1041                                           SmallVectorImpl<uint64_t> &Record,
1042                                           unsigned Abbrev) {
1043   Record.push_back(N->isDistinct());
1044   Record.push_back(N->getTag());
1045   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1046   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1047   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1048   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1049
1050   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1051   Record.clear();
1052 }
1053
1054 static void WriteMDGlobalVariable(const MDGlobalVariable *N,
1055                                   const ValueEnumerator &VE,
1056                                   BitstreamWriter &Stream,
1057                                   SmallVectorImpl<uint64_t> &Record,
1058                                   unsigned Abbrev) {
1059   Record.push_back(N->isDistinct());
1060   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1061   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1062   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1063   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1064   Record.push_back(N->getLine());
1065   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1066   Record.push_back(N->isLocalToUnit());
1067   Record.push_back(N->isDefinition());
1068   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1069   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1070
1071   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1072   Record.clear();
1073 }
1074
1075 static void WriteMDLocalVariable(const MDLocalVariable *,
1076                                  const ValueEnumerator &, BitstreamWriter &,
1077                                  SmallVectorImpl<uint64_t> &, unsigned) {
1078   llvm_unreachable("write not implemented");
1079 }
1080 static void WriteMDExpression(const MDExpression *, const ValueEnumerator &,
1081                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
1082                               unsigned) {
1083   llvm_unreachable("write not implemented");
1084 }
1085 static void WriteMDObjCProperty(const MDObjCProperty *, const ValueEnumerator &,
1086                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
1087                                 unsigned) {
1088   llvm_unreachable("write not implemented");
1089 }
1090 static void WriteMDImportedEntity(const MDImportedEntity *,
1091                                   const ValueEnumerator &, BitstreamWriter &,
1092                                   SmallVectorImpl<uint64_t> &, unsigned) {
1093   llvm_unreachable("write not implemented");
1094 }
1095
1096 static void WriteModuleMetadata(const Module *M,
1097                                 const ValueEnumerator &VE,
1098                                 BitstreamWriter &Stream) {
1099   const auto &MDs = VE.getMDs();
1100   if (MDs.empty() && M->named_metadata_empty())
1101     return;
1102
1103   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1104
1105   unsigned MDSAbbrev = 0;
1106   if (VE.hasMDString()) {
1107     // Abbrev for METADATA_STRING.
1108     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1109     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1110     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1111     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1112     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1113   }
1114
1115   // Initialize MDNode abbreviations.
1116 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1117 #include "llvm/IR/Metadata.def"
1118
1119   if (VE.hasMDLocation()) {
1120     // Abbrev for METADATA_LOCATION.
1121     //
1122     // Assume the column is usually under 128, and always output the inlined-at
1123     // location (it's never more expensive than building an array size 1).
1124     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1125     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1127     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1128     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1129     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1130     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1131     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
1132   }
1133
1134   if (VE.hasGenericDebugNode()) {
1135     // Abbrev for METADATA_GENERIC_DEBUG.
1136     //
1137     // Assume the column is usually under 128, and always output the inlined-at
1138     // location (it's never more expensive than building an array size 1).
1139     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1140     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1141     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1142     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1143     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1144     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1145     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1147     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1148   }
1149
1150   unsigned NameAbbrev = 0;
1151   if (!M->named_metadata_empty()) {
1152     // Abbrev for METADATA_NAME.
1153     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1154     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1155     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1157     NameAbbrev = Stream.EmitAbbrev(Abbv);
1158   }
1159
1160   SmallVector<uint64_t, 64> Record;
1161   for (const Metadata *MD : MDs) {
1162     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1163       switch (N->getMetadataID()) {
1164       default:
1165         llvm_unreachable("Invalid MDNode subclass");
1166 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1167   case Metadata::CLASS##Kind:                                                  \
1168     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1169     continue;
1170 #include "llvm/IR/Metadata.def"
1171       }
1172     }
1173     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1174       WriteValueAsMetadata(MDC, VE, Stream, Record);
1175       continue;
1176     }
1177     const MDString *MDS = cast<MDString>(MD);
1178     // Code: [strchar x N]
1179     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1180
1181     // Emit the finished record.
1182     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1183     Record.clear();
1184   }
1185
1186   // Write named metadata.
1187   for (const NamedMDNode &NMD : M->named_metadata()) {
1188     // Write name.
1189     StringRef Str = NMD.getName();
1190     Record.append(Str.bytes_begin(), Str.bytes_end());
1191     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1192     Record.clear();
1193
1194     // Write named metadata operands.
1195     for (const MDNode *N : NMD.operands())
1196       Record.push_back(VE.getMetadataID(N));
1197     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1198     Record.clear();
1199   }
1200
1201   Stream.ExitBlock();
1202 }
1203
1204 static void WriteFunctionLocalMetadata(const Function &F,
1205                                        const ValueEnumerator &VE,
1206                                        BitstreamWriter &Stream) {
1207   bool StartedMetadataBlock = false;
1208   SmallVector<uint64_t, 64> Record;
1209   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1210       VE.getFunctionLocalMDs();
1211   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1212     assert(MDs[i] && "Expected valid function-local metadata");
1213     if (!StartedMetadataBlock) {
1214       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1215       StartedMetadataBlock = true;
1216     }
1217     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1218   }
1219
1220   if (StartedMetadataBlock)
1221     Stream.ExitBlock();
1222 }
1223
1224 static void WriteMetadataAttachment(const Function &F,
1225                                     const ValueEnumerator &VE,
1226                                     BitstreamWriter &Stream) {
1227   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1228
1229   SmallVector<uint64_t, 64> Record;
1230
1231   // Write metadata attachments
1232   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1233   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1234
1235   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1236     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1237          I != E; ++I) {
1238       MDs.clear();
1239       I->getAllMetadataOtherThanDebugLoc(MDs);
1240
1241       // If no metadata, ignore instruction.
1242       if (MDs.empty()) continue;
1243
1244       Record.push_back(VE.getInstructionID(I));
1245
1246       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1247         Record.push_back(MDs[i].first);
1248         Record.push_back(VE.getMetadataID(MDs[i].second));
1249       }
1250       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1251       Record.clear();
1252     }
1253
1254   Stream.ExitBlock();
1255 }
1256
1257 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1258   SmallVector<uint64_t, 64> Record;
1259
1260   // Write metadata kinds
1261   // METADATA_KIND - [n x [id, name]]
1262   SmallVector<StringRef, 8> Names;
1263   M->getMDKindNames(Names);
1264
1265   if (Names.empty()) return;
1266
1267   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1268
1269   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1270     Record.push_back(MDKindID);
1271     StringRef KName = Names[MDKindID];
1272     Record.append(KName.begin(), KName.end());
1273
1274     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1275     Record.clear();
1276   }
1277
1278   Stream.ExitBlock();
1279 }
1280
1281 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1282   if ((int64_t)V >= 0)
1283     Vals.push_back(V << 1);
1284   else
1285     Vals.push_back((-V << 1) | 1);
1286 }
1287
1288 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1289                            const ValueEnumerator &VE,
1290                            BitstreamWriter &Stream, bool isGlobal) {
1291   if (FirstVal == LastVal) return;
1292
1293   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1294
1295   unsigned AggregateAbbrev = 0;
1296   unsigned String8Abbrev = 0;
1297   unsigned CString7Abbrev = 0;
1298   unsigned CString6Abbrev = 0;
1299   // If this is a constant pool for the module, emit module-specific abbrevs.
1300   if (isGlobal) {
1301     // Abbrev for CST_CODE_AGGREGATE.
1302     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1303     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1306     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1307
1308     // Abbrev for CST_CODE_STRING.
1309     Abbv = new BitCodeAbbrev();
1310     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1313     String8Abbrev = Stream.EmitAbbrev(Abbv);
1314     // Abbrev for CST_CODE_CSTRING.
1315     Abbv = new BitCodeAbbrev();
1316     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1319     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1320     // Abbrev for CST_CODE_CSTRING.
1321     Abbv = new BitCodeAbbrev();
1322     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1324     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1325     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1326   }
1327
1328   SmallVector<uint64_t, 64> Record;
1329
1330   const ValueEnumerator::ValueList &Vals = VE.getValues();
1331   Type *LastTy = nullptr;
1332   for (unsigned i = FirstVal; i != LastVal; ++i) {
1333     const Value *V = Vals[i].first;
1334     // If we need to switch types, do so now.
1335     if (V->getType() != LastTy) {
1336       LastTy = V->getType();
1337       Record.push_back(VE.getTypeID(LastTy));
1338       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1339                         CONSTANTS_SETTYPE_ABBREV);
1340       Record.clear();
1341     }
1342
1343     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1344       Record.push_back(unsigned(IA->hasSideEffects()) |
1345                        unsigned(IA->isAlignStack()) << 1 |
1346                        unsigned(IA->getDialect()&1) << 2);
1347
1348       // Add the asm string.
1349       const std::string &AsmStr = IA->getAsmString();
1350       Record.push_back(AsmStr.size());
1351       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1352         Record.push_back(AsmStr[i]);
1353
1354       // Add the constraint string.
1355       const std::string &ConstraintStr = IA->getConstraintString();
1356       Record.push_back(ConstraintStr.size());
1357       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1358         Record.push_back(ConstraintStr[i]);
1359       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1360       Record.clear();
1361       continue;
1362     }
1363     const Constant *C = cast<Constant>(V);
1364     unsigned Code = -1U;
1365     unsigned AbbrevToUse = 0;
1366     if (C->isNullValue()) {
1367       Code = bitc::CST_CODE_NULL;
1368     } else if (isa<UndefValue>(C)) {
1369       Code = bitc::CST_CODE_UNDEF;
1370     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1371       if (IV->getBitWidth() <= 64) {
1372         uint64_t V = IV->getSExtValue();
1373         emitSignedInt64(Record, V);
1374         Code = bitc::CST_CODE_INTEGER;
1375         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1376       } else {                             // Wide integers, > 64 bits in size.
1377         // We have an arbitrary precision integer value to write whose
1378         // bit width is > 64. However, in canonical unsigned integer
1379         // format it is likely that the high bits are going to be zero.
1380         // So, we only write the number of active words.
1381         unsigned NWords = IV->getValue().getActiveWords();
1382         const uint64_t *RawWords = IV->getValue().getRawData();
1383         for (unsigned i = 0; i != NWords; ++i) {
1384           emitSignedInt64(Record, RawWords[i]);
1385         }
1386         Code = bitc::CST_CODE_WIDE_INTEGER;
1387       }
1388     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1389       Code = bitc::CST_CODE_FLOAT;
1390       Type *Ty = CFP->getType();
1391       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1392         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1393       } else if (Ty->isX86_FP80Ty()) {
1394         // api needed to prevent premature destruction
1395         // bits are not in the same order as a normal i80 APInt, compensate.
1396         APInt api = CFP->getValueAPF().bitcastToAPInt();
1397         const uint64_t *p = api.getRawData();
1398         Record.push_back((p[1] << 48) | (p[0] >> 16));
1399         Record.push_back(p[0] & 0xffffLL);
1400       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1401         APInt api = CFP->getValueAPF().bitcastToAPInt();
1402         const uint64_t *p = api.getRawData();
1403         Record.push_back(p[0]);
1404         Record.push_back(p[1]);
1405       } else {
1406         assert (0 && "Unknown FP type!");
1407       }
1408     } else if (isa<ConstantDataSequential>(C) &&
1409                cast<ConstantDataSequential>(C)->isString()) {
1410       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1411       // Emit constant strings specially.
1412       unsigned NumElts = Str->getNumElements();
1413       // If this is a null-terminated string, use the denser CSTRING encoding.
1414       if (Str->isCString()) {
1415         Code = bitc::CST_CODE_CSTRING;
1416         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1417       } else {
1418         Code = bitc::CST_CODE_STRING;
1419         AbbrevToUse = String8Abbrev;
1420       }
1421       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1422       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1423       for (unsigned i = 0; i != NumElts; ++i) {
1424         unsigned char V = Str->getElementAsInteger(i);
1425         Record.push_back(V);
1426         isCStr7 &= (V & 128) == 0;
1427         if (isCStrChar6)
1428           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1429       }
1430
1431       if (isCStrChar6)
1432         AbbrevToUse = CString6Abbrev;
1433       else if (isCStr7)
1434         AbbrevToUse = CString7Abbrev;
1435     } else if (const ConstantDataSequential *CDS =
1436                   dyn_cast<ConstantDataSequential>(C)) {
1437       Code = bitc::CST_CODE_DATA;
1438       Type *EltTy = CDS->getType()->getElementType();
1439       if (isa<IntegerType>(EltTy)) {
1440         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1441           Record.push_back(CDS->getElementAsInteger(i));
1442       } else if (EltTy->isFloatTy()) {
1443         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1444           union { float F; uint32_t I; };
1445           F = CDS->getElementAsFloat(i);
1446           Record.push_back(I);
1447         }
1448       } else {
1449         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1450         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1451           union { double F; uint64_t I; };
1452           F = CDS->getElementAsDouble(i);
1453           Record.push_back(I);
1454         }
1455       }
1456     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1457                isa<ConstantVector>(C)) {
1458       Code = bitc::CST_CODE_AGGREGATE;
1459       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1460         Record.push_back(VE.getValueID(C->getOperand(i)));
1461       AbbrevToUse = AggregateAbbrev;
1462     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1463       switch (CE->getOpcode()) {
1464       default:
1465         if (Instruction::isCast(CE->getOpcode())) {
1466           Code = bitc::CST_CODE_CE_CAST;
1467           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1468           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1469           Record.push_back(VE.getValueID(C->getOperand(0)));
1470           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1471         } else {
1472           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1473           Code = bitc::CST_CODE_CE_BINOP;
1474           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1475           Record.push_back(VE.getValueID(C->getOperand(0)));
1476           Record.push_back(VE.getValueID(C->getOperand(1)));
1477           uint64_t Flags = GetOptimizationFlags(CE);
1478           if (Flags != 0)
1479             Record.push_back(Flags);
1480         }
1481         break;
1482       case Instruction::GetElementPtr:
1483         Code = bitc::CST_CODE_CE_GEP;
1484         if (cast<GEPOperator>(C)->isInBounds())
1485           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1486         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1487           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1488           Record.push_back(VE.getValueID(C->getOperand(i)));
1489         }
1490         break;
1491       case Instruction::Select:
1492         Code = bitc::CST_CODE_CE_SELECT;
1493         Record.push_back(VE.getValueID(C->getOperand(0)));
1494         Record.push_back(VE.getValueID(C->getOperand(1)));
1495         Record.push_back(VE.getValueID(C->getOperand(2)));
1496         break;
1497       case Instruction::ExtractElement:
1498         Code = bitc::CST_CODE_CE_EXTRACTELT;
1499         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1500         Record.push_back(VE.getValueID(C->getOperand(0)));
1501         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1502         Record.push_back(VE.getValueID(C->getOperand(1)));
1503         break;
1504       case Instruction::InsertElement:
1505         Code = bitc::CST_CODE_CE_INSERTELT;
1506         Record.push_back(VE.getValueID(C->getOperand(0)));
1507         Record.push_back(VE.getValueID(C->getOperand(1)));
1508         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1509         Record.push_back(VE.getValueID(C->getOperand(2)));
1510         break;
1511       case Instruction::ShuffleVector:
1512         // If the return type and argument types are the same, this is a
1513         // standard shufflevector instruction.  If the types are different,
1514         // then the shuffle is widening or truncating the input vectors, and
1515         // the argument type must also be encoded.
1516         if (C->getType() == C->getOperand(0)->getType()) {
1517           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1518         } else {
1519           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1520           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1521         }
1522         Record.push_back(VE.getValueID(C->getOperand(0)));
1523         Record.push_back(VE.getValueID(C->getOperand(1)));
1524         Record.push_back(VE.getValueID(C->getOperand(2)));
1525         break;
1526       case Instruction::ICmp:
1527       case Instruction::FCmp:
1528         Code = bitc::CST_CODE_CE_CMP;
1529         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1530         Record.push_back(VE.getValueID(C->getOperand(0)));
1531         Record.push_back(VE.getValueID(C->getOperand(1)));
1532         Record.push_back(CE->getPredicate());
1533         break;
1534       }
1535     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1536       Code = bitc::CST_CODE_BLOCKADDRESS;
1537       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1538       Record.push_back(VE.getValueID(BA->getFunction()));
1539       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1540     } else {
1541 #ifndef NDEBUG
1542       C->dump();
1543 #endif
1544       llvm_unreachable("Unknown constant!");
1545     }
1546     Stream.EmitRecord(Code, Record, AbbrevToUse);
1547     Record.clear();
1548   }
1549
1550   Stream.ExitBlock();
1551 }
1552
1553 static void WriteModuleConstants(const ValueEnumerator &VE,
1554                                  BitstreamWriter &Stream) {
1555   const ValueEnumerator::ValueList &Vals = VE.getValues();
1556
1557   // Find the first constant to emit, which is the first non-globalvalue value.
1558   // We know globalvalues have been emitted by WriteModuleInfo.
1559   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1560     if (!isa<GlobalValue>(Vals[i].first)) {
1561       WriteConstants(i, Vals.size(), VE, Stream, true);
1562       return;
1563     }
1564   }
1565 }
1566
1567 /// PushValueAndType - The file has to encode both the value and type id for
1568 /// many values, because we need to know what type to create for forward
1569 /// references.  However, most operands are not forward references, so this type
1570 /// field is not needed.
1571 ///
1572 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1573 /// instruction ID, then it is a forward reference, and it also includes the
1574 /// type ID.  The value ID that is written is encoded relative to the InstID.
1575 static bool PushValueAndType(const Value *V, unsigned InstID,
1576                              SmallVectorImpl<unsigned> &Vals,
1577                              ValueEnumerator &VE) {
1578   unsigned ValID = VE.getValueID(V);
1579   // Make encoding relative to the InstID.
1580   Vals.push_back(InstID - ValID);
1581   if (ValID >= InstID) {
1582     Vals.push_back(VE.getTypeID(V->getType()));
1583     return true;
1584   }
1585   return false;
1586 }
1587
1588 /// pushValue - Like PushValueAndType, but where the type of the value is
1589 /// omitted (perhaps it was already encoded in an earlier operand).
1590 static void pushValue(const Value *V, unsigned InstID,
1591                       SmallVectorImpl<unsigned> &Vals,
1592                       ValueEnumerator &VE) {
1593   unsigned ValID = VE.getValueID(V);
1594   Vals.push_back(InstID - ValID);
1595 }
1596
1597 static void pushValueSigned(const Value *V, unsigned InstID,
1598                             SmallVectorImpl<uint64_t> &Vals,
1599                             ValueEnumerator &VE) {
1600   unsigned ValID = VE.getValueID(V);
1601   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1602   emitSignedInt64(Vals, diff);
1603 }
1604
1605 /// WriteInstruction - Emit an instruction to the specified stream.
1606 static void WriteInstruction(const Instruction &I, unsigned InstID,
1607                              ValueEnumerator &VE, BitstreamWriter &Stream,
1608                              SmallVectorImpl<unsigned> &Vals) {
1609   unsigned Code = 0;
1610   unsigned AbbrevToUse = 0;
1611   VE.setInstructionID(&I);
1612   switch (I.getOpcode()) {
1613   default:
1614     if (Instruction::isCast(I.getOpcode())) {
1615       Code = bitc::FUNC_CODE_INST_CAST;
1616       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1617         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1618       Vals.push_back(VE.getTypeID(I.getType()));
1619       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1620     } else {
1621       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1622       Code = bitc::FUNC_CODE_INST_BINOP;
1623       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1624         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1625       pushValue(I.getOperand(1), InstID, Vals, VE);
1626       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1627       uint64_t Flags = GetOptimizationFlags(&I);
1628       if (Flags != 0) {
1629         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1630           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1631         Vals.push_back(Flags);
1632       }
1633     }
1634     break;
1635
1636   case Instruction::GetElementPtr:
1637     Code = bitc::FUNC_CODE_INST_GEP;
1638     if (cast<GEPOperator>(&I)->isInBounds())
1639       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1640     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1641       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1642     break;
1643   case Instruction::ExtractValue: {
1644     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1645     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1646     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1647     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1648       Vals.push_back(*i);
1649     break;
1650   }
1651   case Instruction::InsertValue: {
1652     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1653     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1654     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1655     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1656     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1657       Vals.push_back(*i);
1658     break;
1659   }
1660   case Instruction::Select:
1661     Code = bitc::FUNC_CODE_INST_VSELECT;
1662     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1663     pushValue(I.getOperand(2), InstID, Vals, VE);
1664     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1665     break;
1666   case Instruction::ExtractElement:
1667     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1668     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1669     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1670     break;
1671   case Instruction::InsertElement:
1672     Code = bitc::FUNC_CODE_INST_INSERTELT;
1673     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1674     pushValue(I.getOperand(1), InstID, Vals, VE);
1675     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1676     break;
1677   case Instruction::ShuffleVector:
1678     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1679     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1680     pushValue(I.getOperand(1), InstID, Vals, VE);
1681     pushValue(I.getOperand(2), InstID, Vals, VE);
1682     break;
1683   case Instruction::ICmp:
1684   case Instruction::FCmp:
1685     // compare returning Int1Ty or vector of Int1Ty
1686     Code = bitc::FUNC_CODE_INST_CMP2;
1687     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1688     pushValue(I.getOperand(1), InstID, Vals, VE);
1689     Vals.push_back(cast<CmpInst>(I).getPredicate());
1690     break;
1691
1692   case Instruction::Ret:
1693     {
1694       Code = bitc::FUNC_CODE_INST_RET;
1695       unsigned NumOperands = I.getNumOperands();
1696       if (NumOperands == 0)
1697         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1698       else if (NumOperands == 1) {
1699         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1700           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1701       } else {
1702         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1703           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1704       }
1705     }
1706     break;
1707   case Instruction::Br:
1708     {
1709       Code = bitc::FUNC_CODE_INST_BR;
1710       const BranchInst &II = cast<BranchInst>(I);
1711       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1712       if (II.isConditional()) {
1713         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1714         pushValue(II.getCondition(), InstID, Vals, VE);
1715       }
1716     }
1717     break;
1718   case Instruction::Switch:
1719     {
1720       Code = bitc::FUNC_CODE_INST_SWITCH;
1721       const SwitchInst &SI = cast<SwitchInst>(I);
1722       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1723       pushValue(SI.getCondition(), InstID, Vals, VE);
1724       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1725       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1726            i != e; ++i) {
1727         Vals.push_back(VE.getValueID(i.getCaseValue()));
1728         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1729       }
1730     }
1731     break;
1732   case Instruction::IndirectBr:
1733     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1734     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1735     // Encode the address operand as relative, but not the basic blocks.
1736     pushValue(I.getOperand(0), InstID, Vals, VE);
1737     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1738       Vals.push_back(VE.getValueID(I.getOperand(i)));
1739     break;
1740
1741   case Instruction::Invoke: {
1742     const InvokeInst *II = cast<InvokeInst>(&I);
1743     const Value *Callee(II->getCalledValue());
1744     PointerType *PTy = cast<PointerType>(Callee->getType());
1745     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1746     Code = bitc::FUNC_CODE_INST_INVOKE;
1747
1748     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1749     Vals.push_back(II->getCallingConv());
1750     Vals.push_back(VE.getValueID(II->getNormalDest()));
1751     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1752     PushValueAndType(Callee, InstID, Vals, VE);
1753
1754     // Emit value #'s for the fixed parameters.
1755     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1756       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1757
1758     // Emit type/value pairs for varargs params.
1759     if (FTy->isVarArg()) {
1760       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1761            i != e; ++i)
1762         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1763     }
1764     break;
1765   }
1766   case Instruction::Resume:
1767     Code = bitc::FUNC_CODE_INST_RESUME;
1768     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1769     break;
1770   case Instruction::Unreachable:
1771     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1772     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1773     break;
1774
1775   case Instruction::PHI: {
1776     const PHINode &PN = cast<PHINode>(I);
1777     Code = bitc::FUNC_CODE_INST_PHI;
1778     // With the newer instruction encoding, forward references could give
1779     // negative valued IDs.  This is most common for PHIs, so we use
1780     // signed VBRs.
1781     SmallVector<uint64_t, 128> Vals64;
1782     Vals64.push_back(VE.getTypeID(PN.getType()));
1783     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1784       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1785       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1786     }
1787     // Emit a Vals64 vector and exit.
1788     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1789     Vals64.clear();
1790     return;
1791   }
1792
1793   case Instruction::LandingPad: {
1794     const LandingPadInst &LP = cast<LandingPadInst>(I);
1795     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1796     Vals.push_back(VE.getTypeID(LP.getType()));
1797     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1798     Vals.push_back(LP.isCleanup());
1799     Vals.push_back(LP.getNumClauses());
1800     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1801       if (LP.isCatch(I))
1802         Vals.push_back(LandingPadInst::Catch);
1803       else
1804         Vals.push_back(LandingPadInst::Filter);
1805       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1806     }
1807     break;
1808   }
1809
1810   case Instruction::Alloca: {
1811     Code = bitc::FUNC_CODE_INST_ALLOCA;
1812     Vals.push_back(VE.getTypeID(I.getType()));
1813     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1814     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1815     const AllocaInst &AI = cast<AllocaInst>(I);
1816     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1817     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1818            "not enough bits for maximum alignment");
1819     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1820     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1821     Vals.push_back(AlignRecord);
1822     break;
1823   }
1824
1825   case Instruction::Load:
1826     if (cast<LoadInst>(I).isAtomic()) {
1827       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1828       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1829     } else {
1830       Code = bitc::FUNC_CODE_INST_LOAD;
1831       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1832         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1833     }
1834     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1835     Vals.push_back(cast<LoadInst>(I).isVolatile());
1836     if (cast<LoadInst>(I).isAtomic()) {
1837       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1838       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1839     }
1840     break;
1841   case Instruction::Store:
1842     if (cast<StoreInst>(I).isAtomic())
1843       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1844     else
1845       Code = bitc::FUNC_CODE_INST_STORE;
1846     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1847     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1848     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1849     Vals.push_back(cast<StoreInst>(I).isVolatile());
1850     if (cast<StoreInst>(I).isAtomic()) {
1851       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1852       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1853     }
1854     break;
1855   case Instruction::AtomicCmpXchg:
1856     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1857     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1858     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1859     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1860     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1861     Vals.push_back(GetEncodedOrdering(
1862                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1863     Vals.push_back(GetEncodedSynchScope(
1864                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1865     Vals.push_back(GetEncodedOrdering(
1866                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1867     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1868     break;
1869   case Instruction::AtomicRMW:
1870     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1871     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1872     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1873     Vals.push_back(GetEncodedRMWOperation(
1874                      cast<AtomicRMWInst>(I).getOperation()));
1875     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1876     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1877     Vals.push_back(GetEncodedSynchScope(
1878                      cast<AtomicRMWInst>(I).getSynchScope()));
1879     break;
1880   case Instruction::Fence:
1881     Code = bitc::FUNC_CODE_INST_FENCE;
1882     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1883     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1884     break;
1885   case Instruction::Call: {
1886     const CallInst &CI = cast<CallInst>(I);
1887     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1888     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1889
1890     Code = bitc::FUNC_CODE_INST_CALL;
1891
1892     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1893     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1894                    unsigned(CI.isMustTailCall()) << 14);
1895     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1896
1897     // Emit value #'s for the fixed parameters.
1898     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1899       // Check for labels (can happen with asm labels).
1900       if (FTy->getParamType(i)->isLabelTy())
1901         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1902       else
1903         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1904     }
1905
1906     // Emit type/value pairs for varargs params.
1907     if (FTy->isVarArg()) {
1908       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1909            i != e; ++i)
1910         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1911     }
1912     break;
1913   }
1914   case Instruction::VAArg:
1915     Code = bitc::FUNC_CODE_INST_VAARG;
1916     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1917     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1918     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1919     break;
1920   }
1921
1922   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1923   Vals.clear();
1924 }
1925
1926 // Emit names for globals/functions etc.
1927 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1928                                   const ValueEnumerator &VE,
1929                                   BitstreamWriter &Stream) {
1930   if (VST.empty()) return;
1931   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1932
1933   // FIXME: Set up the abbrev, we know how many values there are!
1934   // FIXME: We know if the type names can use 7-bit ascii.
1935   SmallVector<unsigned, 64> NameVals;
1936
1937   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1938        SI != SE; ++SI) {
1939
1940     const ValueName &Name = *SI;
1941
1942     // Figure out the encoding to use for the name.
1943     bool is7Bit = true;
1944     bool isChar6 = true;
1945     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1946          C != E; ++C) {
1947       if (isChar6)
1948         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1949       if ((unsigned char)*C & 128) {
1950         is7Bit = false;
1951         break;  // don't bother scanning the rest.
1952       }
1953     }
1954
1955     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1956
1957     // VST_ENTRY:   [valueid, namechar x N]
1958     // VST_BBENTRY: [bbid, namechar x N]
1959     unsigned Code;
1960     if (isa<BasicBlock>(SI->getValue())) {
1961       Code = bitc::VST_CODE_BBENTRY;
1962       if (isChar6)
1963         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1964     } else {
1965       Code = bitc::VST_CODE_ENTRY;
1966       if (isChar6)
1967         AbbrevToUse = VST_ENTRY_6_ABBREV;
1968       else if (is7Bit)
1969         AbbrevToUse = VST_ENTRY_7_ABBREV;
1970     }
1971
1972     NameVals.push_back(VE.getValueID(SI->getValue()));
1973     for (const char *P = Name.getKeyData(),
1974          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1975       NameVals.push_back((unsigned char)*P);
1976
1977     // Emit the finished record.
1978     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1979     NameVals.clear();
1980   }
1981   Stream.ExitBlock();
1982 }
1983
1984 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1985                          BitstreamWriter &Stream) {
1986   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1987   unsigned Code;
1988   if (isa<BasicBlock>(Order.V))
1989     Code = bitc::USELIST_CODE_BB;
1990   else
1991     Code = bitc::USELIST_CODE_DEFAULT;
1992
1993   SmallVector<uint64_t, 64> Record;
1994   for (unsigned I : Order.Shuffle)
1995     Record.push_back(I);
1996   Record.push_back(VE.getValueID(Order.V));
1997   Stream.EmitRecord(Code, Record);
1998 }
1999
2000 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2001                               BitstreamWriter &Stream) {
2002   auto hasMore = [&]() {
2003     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2004   };
2005   if (!hasMore())
2006     // Nothing to do.
2007     return;
2008
2009   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2010   while (hasMore()) {
2011     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2012     VE.UseListOrders.pop_back();
2013   }
2014   Stream.ExitBlock();
2015 }
2016
2017 /// WriteFunction - Emit a function body to the module stream.
2018 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2019                           BitstreamWriter &Stream) {
2020   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2021   VE.incorporateFunction(F);
2022
2023   SmallVector<unsigned, 64> Vals;
2024
2025   // Emit the number of basic blocks, so the reader can create them ahead of
2026   // time.
2027   Vals.push_back(VE.getBasicBlocks().size());
2028   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2029   Vals.clear();
2030
2031   // If there are function-local constants, emit them now.
2032   unsigned CstStart, CstEnd;
2033   VE.getFunctionConstantRange(CstStart, CstEnd);
2034   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2035
2036   // If there is function-local metadata, emit it now.
2037   WriteFunctionLocalMetadata(F, VE, Stream);
2038
2039   // Keep a running idea of what the instruction ID is.
2040   unsigned InstID = CstEnd;
2041
2042   bool NeedsMetadataAttachment = false;
2043
2044   DebugLoc LastDL;
2045
2046   // Finally, emit all the instructions, in order.
2047   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2048     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2049          I != E; ++I) {
2050       WriteInstruction(*I, InstID, VE, Stream, Vals);
2051
2052       if (!I->getType()->isVoidTy())
2053         ++InstID;
2054
2055       // If the instruction has metadata, write a metadata attachment later.
2056       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2057
2058       // If the instruction has a debug location, emit it.
2059       DebugLoc DL = I->getDebugLoc();
2060       if (DL.isUnknown()) {
2061         // nothing todo.
2062       } else if (DL == LastDL) {
2063         // Just repeat the same debug loc as last time.
2064         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2065       } else {
2066         MDNode *Scope, *IA;
2067         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
2068         assert(Scope && "Expected valid scope");
2069
2070         Vals.push_back(DL.getLine());
2071         Vals.push_back(DL.getCol());
2072         Vals.push_back(VE.getMetadataOrNullID(Scope));
2073         Vals.push_back(VE.getMetadataOrNullID(IA));
2074         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2075         Vals.clear();
2076
2077         LastDL = DL;
2078       }
2079     }
2080
2081   // Emit names for all the instructions etc.
2082   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2083
2084   if (NeedsMetadataAttachment)
2085     WriteMetadataAttachment(F, VE, Stream);
2086   if (shouldPreserveBitcodeUseListOrder())
2087     WriteUseListBlock(&F, VE, Stream);
2088   VE.purgeFunction();
2089   Stream.ExitBlock();
2090 }
2091
2092 // Emit blockinfo, which defines the standard abbreviations etc.
2093 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2094   // We only want to emit block info records for blocks that have multiple
2095   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2096   // Other blocks can define their abbrevs inline.
2097   Stream.EnterBlockInfoBlock(2);
2098
2099   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2100     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2101     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2104     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2105     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2106                                    Abbv) != VST_ENTRY_8_ABBREV)
2107       llvm_unreachable("Unexpected abbrev ordering!");
2108   }
2109
2110   { // 7-bit fixed width VST_ENTRY strings.
2111     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2112     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2113     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2114     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2115     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2116     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2117                                    Abbv) != VST_ENTRY_7_ABBREV)
2118       llvm_unreachable("Unexpected abbrev ordering!");
2119   }
2120   { // 6-bit char6 VST_ENTRY strings.
2121     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2122     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2123     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2126     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2127                                    Abbv) != VST_ENTRY_6_ABBREV)
2128       llvm_unreachable("Unexpected abbrev ordering!");
2129   }
2130   { // 6-bit char6 VST_BBENTRY strings.
2131     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2132     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2133     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2134     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2136     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2137                                    Abbv) != VST_BBENTRY_6_ABBREV)
2138       llvm_unreachable("Unexpected abbrev ordering!");
2139   }
2140
2141
2142
2143   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2144     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2145     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2147                               Log2_32_Ceil(VE.getTypes().size()+1)));
2148     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2149                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2150       llvm_unreachable("Unexpected abbrev ordering!");
2151   }
2152
2153   { // INTEGER abbrev for CONSTANTS_BLOCK.
2154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2155     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2157     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2158                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2159       llvm_unreachable("Unexpected abbrev ordering!");
2160   }
2161
2162   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2163     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2164     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2167                               Log2_32_Ceil(VE.getTypes().size()+1)));
2168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2169
2170     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2171                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2172       llvm_unreachable("Unexpected abbrev ordering!");
2173   }
2174   { // NULL abbrev for CONSTANTS_BLOCK.
2175     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2176     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2177     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2178                                    Abbv) != CONSTANTS_NULL_Abbrev)
2179       llvm_unreachable("Unexpected abbrev ordering!");
2180   }
2181
2182   // FIXME: This should only use space for first class types!
2183
2184   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2185     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2186     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2190     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2191                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2192       llvm_unreachable("Unexpected abbrev ordering!");
2193   }
2194   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2195     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2196     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2200     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2201                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2202       llvm_unreachable("Unexpected abbrev ordering!");
2203   }
2204   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2205     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2206     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2207     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2211     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2212                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2213       llvm_unreachable("Unexpected abbrev ordering!");
2214   }
2215   { // INST_CAST abbrev for FUNCTION_BLOCK.
2216     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2217     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2218     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2219     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2220                               Log2_32_Ceil(VE.getTypes().size()+1)));
2221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2222     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2223                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2224       llvm_unreachable("Unexpected abbrev ordering!");
2225   }
2226
2227   { // INST_RET abbrev for FUNCTION_BLOCK.
2228     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2229     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2230     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2231                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2232       llvm_unreachable("Unexpected abbrev ordering!");
2233   }
2234   { // INST_RET abbrev for FUNCTION_BLOCK.
2235     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2236     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2238     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2239                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2240       llvm_unreachable("Unexpected abbrev ordering!");
2241   }
2242   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2243     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2244     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2245     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2246                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2247       llvm_unreachable("Unexpected abbrev ordering!");
2248   }
2249
2250   Stream.ExitBlock();
2251 }
2252
2253 /// WriteModule - Emit the specified module to the bitstream.
2254 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2255   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2256
2257   SmallVector<unsigned, 1> Vals;
2258   unsigned CurVersion = 1;
2259   Vals.push_back(CurVersion);
2260   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2261
2262   // Analyze the module, enumerating globals, functions, etc.
2263   ValueEnumerator VE(*M);
2264
2265   // Emit blockinfo, which defines the standard abbreviations etc.
2266   WriteBlockInfo(VE, Stream);
2267
2268   // Emit information about attribute groups.
2269   WriteAttributeGroupTable(VE, Stream);
2270
2271   // Emit information about parameter attributes.
2272   WriteAttributeTable(VE, Stream);
2273
2274   // Emit information describing all of the types in the module.
2275   WriteTypeTable(VE, Stream);
2276
2277   writeComdats(VE, Stream);
2278
2279   // Emit top-level description of module, including target triple, inline asm,
2280   // descriptors for global variables, and function prototype info.
2281   WriteModuleInfo(M, VE, Stream);
2282
2283   // Emit constants.
2284   WriteModuleConstants(VE, Stream);
2285
2286   // Emit metadata.
2287   WriteModuleMetadata(M, VE, Stream);
2288
2289   // Emit metadata.
2290   WriteModuleMetadataStore(M, Stream);
2291
2292   // Emit names for globals/functions etc.
2293   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2294
2295   // Emit module-level use-lists.
2296   if (shouldPreserveBitcodeUseListOrder())
2297     WriteUseListBlock(nullptr, VE, Stream);
2298
2299   // Emit function bodies.
2300   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2301     if (!F->isDeclaration())
2302       WriteFunction(*F, VE, Stream);
2303
2304   Stream.ExitBlock();
2305 }
2306
2307 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2308 /// header and trailer to make it compatible with the system archiver.  To do
2309 /// this we emit the following header, and then emit a trailer that pads the
2310 /// file out to be a multiple of 16 bytes.
2311 ///
2312 /// struct bc_header {
2313 ///   uint32_t Magic;         // 0x0B17C0DE
2314 ///   uint32_t Version;       // Version, currently always 0.
2315 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2316 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2317 ///   uint32_t CPUType;       // CPU specifier.
2318 ///   ... potentially more later ...
2319 /// };
2320 enum {
2321   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2322   DarwinBCHeaderSize = 5*4
2323 };
2324
2325 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2326                                uint32_t &Position) {
2327   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2328   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2329   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2330   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2331   Position += 4;
2332 }
2333
2334 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2335                                          const Triple &TT) {
2336   unsigned CPUType = ~0U;
2337
2338   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2339   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2340   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2341   // specific constants here because they are implicitly part of the Darwin ABI.
2342   enum {
2343     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2344     DARWIN_CPU_TYPE_X86        = 7,
2345     DARWIN_CPU_TYPE_ARM        = 12,
2346     DARWIN_CPU_TYPE_POWERPC    = 18
2347   };
2348
2349   Triple::ArchType Arch = TT.getArch();
2350   if (Arch == Triple::x86_64)
2351     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2352   else if (Arch == Triple::x86)
2353     CPUType = DARWIN_CPU_TYPE_X86;
2354   else if (Arch == Triple::ppc)
2355     CPUType = DARWIN_CPU_TYPE_POWERPC;
2356   else if (Arch == Triple::ppc64)
2357     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2358   else if (Arch == Triple::arm || Arch == Triple::thumb)
2359     CPUType = DARWIN_CPU_TYPE_ARM;
2360
2361   // Traditional Bitcode starts after header.
2362   assert(Buffer.size() >= DarwinBCHeaderSize &&
2363          "Expected header size to be reserved");
2364   unsigned BCOffset = DarwinBCHeaderSize;
2365   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2366
2367   // Write the magic and version.
2368   unsigned Position = 0;
2369   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2370   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2371   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2372   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2373   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2374
2375   // If the file is not a multiple of 16 bytes, insert dummy padding.
2376   while (Buffer.size() & 15)
2377     Buffer.push_back(0);
2378 }
2379
2380 /// WriteBitcodeToFile - Write the specified module to the specified output
2381 /// stream.
2382 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2383   SmallVector<char, 0> Buffer;
2384   Buffer.reserve(256*1024);
2385
2386   // If this is darwin or another generic macho target, reserve space for the
2387   // header.
2388   Triple TT(M->getTargetTriple());
2389   if (TT.isOSDarwin())
2390     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2391
2392   // Emit the module into the buffer.
2393   {
2394     BitstreamWriter Stream(Buffer);
2395
2396     // Emit the file header.
2397     Stream.Emit((unsigned)'B', 8);
2398     Stream.Emit((unsigned)'C', 8);
2399     Stream.Emit(0x0, 4);
2400     Stream.Emit(0xC, 4);
2401     Stream.Emit(0xE, 4);
2402     Stream.Emit(0xD, 4);
2403
2404     // Emit the module.
2405     WriteModule(M, Stream);
2406   }
2407
2408   if (TT.isOSDarwin())
2409     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2410
2411   // Write the generated bitstream to "Out".
2412   Out.write((char*)&Buffer.front(), Buffer.size());
2413 }