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 *,
 997                                     const ValueEnumerator &, BitstreamWriter &,
 998                                     SmallVectorImpl<uint64_t> &, unsigned) {
 999   llvm_unreachable("write not implemented");
1000 }
1001 static void WriteMDNamespace(const MDNamespace *, const ValueEnumerator &,
1002                              BitstreamWriter &, SmallVectorImpl<uint64_t> &,
1003                              unsigned) {
1004   llvm_unreachable("write not implemented");
1005 }
1006 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *,
1007                                          const ValueEnumerator &,
1008                                          BitstreamWriter &,
1009                                          SmallVectorImpl<uint64_t> &,
1010                                          unsigned) {
1011   llvm_unreachable("write not implemented");
1012 }
1013 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *,
1014                                           const ValueEnumerator &,
1015                                           BitstreamWriter &,
1016                                           SmallVectorImpl<uint64_t> &,
1017                                           unsigned) {
1018   llvm_unreachable("write not implemented");
1019 }
1020 static void WriteMDGlobalVariable(const MDGlobalVariable *,
1021                                   const ValueEnumerator &, BitstreamWriter &,
1022                                   SmallVectorImpl<uint64_t> &, unsigned) {
1023   llvm_unreachable("write not implemented");
1024 }
1025 static void WriteMDLocalVariable(const MDLocalVariable *,
1026                                  const ValueEnumerator &, BitstreamWriter &,
1027                                  SmallVectorImpl<uint64_t> &, unsigned) {
1028   llvm_unreachable("write not implemented");
1029 }
1030 static void WriteMDExpression(const MDExpression *, const ValueEnumerator &,
1031                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
1032                               unsigned) {
1033   llvm_unreachable("write not implemented");
1034 }
1035 static void WriteMDObjCProperty(const MDObjCProperty *, const ValueEnumerator &,
1036                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
1037                                 unsigned) {
1038   llvm_unreachable("write not implemented");
1039 }
1040 static void WriteMDImportedEntity(const MDImportedEntity *,
1041                                   const ValueEnumerator &, BitstreamWriter &,
1042                                   SmallVectorImpl<uint64_t> &, unsigned) {
1043   llvm_unreachable("write not implemented");
1044 }
1045
1046 static void WriteModuleMetadata(const Module *M,
1047                                 const ValueEnumerator &VE,
1048                                 BitstreamWriter &Stream) {
1049   const auto &MDs = VE.getMDs();
1050   if (MDs.empty() && M->named_metadata_empty())
1051     return;
1052
1053   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1054
1055   unsigned MDSAbbrev = 0;
1056   if (VE.hasMDString()) {
1057     // Abbrev for METADATA_STRING.
1058     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1059     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1060     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1061     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1062     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1063   }
1064
1065   // Initialize MDNode abbreviations.
1066 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1067 #include "llvm/IR/Metadata.def"
1068
1069   if (VE.hasMDLocation()) {
1070     // Abbrev for METADATA_LOCATION.
1071     //
1072     // Assume the column is usually under 128, and always output the inlined-at
1073     // location (it's never more expensive than building an array size 1).
1074     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1075     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1076     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1077     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1078     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1079     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1080     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1081     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
1082   }
1083
1084   if (VE.hasGenericDebugNode()) {
1085     // Abbrev for METADATA_GENERIC_DEBUG.
1086     //
1087     // Assume the column is usually under 128, and always output the inlined-at
1088     // location (it's never more expensive than building an array size 1).
1089     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1090     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1091     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1092     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1093     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1094     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1095     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1096     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1097     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1098   }
1099
1100   unsigned NameAbbrev = 0;
1101   if (!M->named_metadata_empty()) {
1102     // Abbrev for METADATA_NAME.
1103     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1104     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1105     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1106     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1107     NameAbbrev = Stream.EmitAbbrev(Abbv);
1108   }
1109
1110   SmallVector<uint64_t, 64> Record;
1111   for (const Metadata *MD : MDs) {
1112     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1113       switch (N->getMetadataID()) {
1114       default:
1115         llvm_unreachable("Invalid MDNode subclass");
1116 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1117   case Metadata::CLASS##Kind:                                                  \
1118     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1119     continue;
1120 #include "llvm/IR/Metadata.def"
1121       }
1122     }
1123     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1124       WriteValueAsMetadata(MDC, VE, Stream, Record);
1125       continue;
1126     }
1127     const MDString *MDS = cast<MDString>(MD);
1128     // Code: [strchar x N]
1129     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1130
1131     // Emit the finished record.
1132     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1133     Record.clear();
1134   }
1135
1136   // Write named metadata.
1137   for (const NamedMDNode &NMD : M->named_metadata()) {
1138     // Write name.
1139     StringRef Str = NMD.getName();
1140     Record.append(Str.bytes_begin(), Str.bytes_end());
1141     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1142     Record.clear();
1143
1144     // Write named metadata operands.
1145     for (const MDNode *N : NMD.operands())
1146       Record.push_back(VE.getMetadataID(N));
1147     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1148     Record.clear();
1149   }
1150
1151   Stream.ExitBlock();
1152 }
1153
1154 static void WriteFunctionLocalMetadata(const Function &F,
1155                                        const ValueEnumerator &VE,
1156                                        BitstreamWriter &Stream) {
1157   bool StartedMetadataBlock = false;
1158   SmallVector<uint64_t, 64> Record;
1159   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1160       VE.getFunctionLocalMDs();
1161   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1162     assert(MDs[i] && "Expected valid function-local metadata");
1163     if (!StartedMetadataBlock) {
1164       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1165       StartedMetadataBlock = true;
1166     }
1167     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1168   }
1169
1170   if (StartedMetadataBlock)
1171     Stream.ExitBlock();
1172 }
1173
1174 static void WriteMetadataAttachment(const Function &F,
1175                                     const ValueEnumerator &VE,
1176                                     BitstreamWriter &Stream) {
1177   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1178
1179   SmallVector<uint64_t, 64> Record;
1180
1181   // Write metadata attachments
1182   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1183   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1184
1185   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1186     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1187          I != E; ++I) {
1188       MDs.clear();
1189       I->getAllMetadataOtherThanDebugLoc(MDs);
1190
1191       // If no metadata, ignore instruction.
1192       if (MDs.empty()) continue;
1193
1194       Record.push_back(VE.getInstructionID(I));
1195
1196       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1197         Record.push_back(MDs[i].first);
1198         Record.push_back(VE.getMetadataID(MDs[i].second));
1199       }
1200       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1201       Record.clear();
1202     }
1203
1204   Stream.ExitBlock();
1205 }
1206
1207 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1208   SmallVector<uint64_t, 64> Record;
1209
1210   // Write metadata kinds
1211   // METADATA_KIND - [n x [id, name]]
1212   SmallVector<StringRef, 8> Names;
1213   M->getMDKindNames(Names);
1214
1215   if (Names.empty()) return;
1216
1217   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1218
1219   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1220     Record.push_back(MDKindID);
1221     StringRef KName = Names[MDKindID];
1222     Record.append(KName.begin(), KName.end());
1223
1224     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1225     Record.clear();
1226   }
1227
1228   Stream.ExitBlock();
1229 }
1230
1231 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1232   if ((int64_t)V >= 0)
1233     Vals.push_back(V << 1);
1234   else
1235     Vals.push_back((-V << 1) | 1);
1236 }
1237
1238 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1239                            const ValueEnumerator &VE,
1240                            BitstreamWriter &Stream, bool isGlobal) {
1241   if (FirstVal == LastVal) return;
1242
1243   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1244
1245   unsigned AggregateAbbrev = 0;
1246   unsigned String8Abbrev = 0;
1247   unsigned CString7Abbrev = 0;
1248   unsigned CString6Abbrev = 0;
1249   // If this is a constant pool for the module, emit module-specific abbrevs.
1250   if (isGlobal) {
1251     // Abbrev for CST_CODE_AGGREGATE.
1252     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1253     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1256     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1257
1258     // Abbrev for CST_CODE_STRING.
1259     Abbv = new BitCodeAbbrev();
1260     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1262     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1263     String8Abbrev = Stream.EmitAbbrev(Abbv);
1264     // Abbrev for CST_CODE_CSTRING.
1265     Abbv = new BitCodeAbbrev();
1266     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1269     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1270     // Abbrev for CST_CODE_CSTRING.
1271     Abbv = new BitCodeAbbrev();
1272     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1273     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1274     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1275     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1276   }
1277
1278   SmallVector<uint64_t, 64> Record;
1279
1280   const ValueEnumerator::ValueList &Vals = VE.getValues();
1281   Type *LastTy = nullptr;
1282   for (unsigned i = FirstVal; i != LastVal; ++i) {
1283     const Value *V = Vals[i].first;
1284     // If we need to switch types, do so now.
1285     if (V->getType() != LastTy) {
1286       LastTy = V->getType();
1287       Record.push_back(VE.getTypeID(LastTy));
1288       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1289                         CONSTANTS_SETTYPE_ABBREV);
1290       Record.clear();
1291     }
1292
1293     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1294       Record.push_back(unsigned(IA->hasSideEffects()) |
1295                        unsigned(IA->isAlignStack()) << 1 |
1296                        unsigned(IA->getDialect()&1) << 2);
1297
1298       // Add the asm string.
1299       const std::string &AsmStr = IA->getAsmString();
1300       Record.push_back(AsmStr.size());
1301       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1302         Record.push_back(AsmStr[i]);
1303
1304       // Add the constraint string.
1305       const std::string &ConstraintStr = IA->getConstraintString();
1306       Record.push_back(ConstraintStr.size());
1307       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1308         Record.push_back(ConstraintStr[i]);
1309       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1310       Record.clear();
1311       continue;
1312     }
1313     const Constant *C = cast<Constant>(V);
1314     unsigned Code = -1U;
1315     unsigned AbbrevToUse = 0;
1316     if (C->isNullValue()) {
1317       Code = bitc::CST_CODE_NULL;
1318     } else if (isa<UndefValue>(C)) {
1319       Code = bitc::CST_CODE_UNDEF;
1320     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1321       if (IV->getBitWidth() <= 64) {
1322         uint64_t V = IV->getSExtValue();
1323         emitSignedInt64(Record, V);
1324         Code = bitc::CST_CODE_INTEGER;
1325         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1326       } else {                             // Wide integers, > 64 bits in size.
1327         // We have an arbitrary precision integer value to write whose
1328         // bit width is > 64. However, in canonical unsigned integer
1329         // format it is likely that the high bits are going to be zero.
1330         // So, we only write the number of active words.
1331         unsigned NWords = IV->getValue().getActiveWords();
1332         const uint64_t *RawWords = IV->getValue().getRawData();
1333         for (unsigned i = 0; i != NWords; ++i) {
1334           emitSignedInt64(Record, RawWords[i]);
1335         }
1336         Code = bitc::CST_CODE_WIDE_INTEGER;
1337       }
1338     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1339       Code = bitc::CST_CODE_FLOAT;
1340       Type *Ty = CFP->getType();
1341       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1342         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1343       } else if (Ty->isX86_FP80Ty()) {
1344         // api needed to prevent premature destruction
1345         // bits are not in the same order as a normal i80 APInt, compensate.
1346         APInt api = CFP->getValueAPF().bitcastToAPInt();
1347         const uint64_t *p = api.getRawData();
1348         Record.push_back((p[1] << 48) | (p[0] >> 16));
1349         Record.push_back(p[0] & 0xffffLL);
1350       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1351         APInt api = CFP->getValueAPF().bitcastToAPInt();
1352         const uint64_t *p = api.getRawData();
1353         Record.push_back(p[0]);
1354         Record.push_back(p[1]);
1355       } else {
1356         assert (0 && "Unknown FP type!");
1357       }
1358     } else if (isa<ConstantDataSequential>(C) &&
1359                cast<ConstantDataSequential>(C)->isString()) {
1360       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1361       // Emit constant strings specially.
1362       unsigned NumElts = Str->getNumElements();
1363       // If this is a null-terminated string, use the denser CSTRING encoding.
1364       if (Str->isCString()) {
1365         Code = bitc::CST_CODE_CSTRING;
1366         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1367       } else {
1368         Code = bitc::CST_CODE_STRING;
1369         AbbrevToUse = String8Abbrev;
1370       }
1371       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1372       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1373       for (unsigned i = 0; i != NumElts; ++i) {
1374         unsigned char V = Str->getElementAsInteger(i);
1375         Record.push_back(V);
1376         isCStr7 &= (V & 128) == 0;
1377         if (isCStrChar6)
1378           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1379       }
1380
1381       if (isCStrChar6)
1382         AbbrevToUse = CString6Abbrev;
1383       else if (isCStr7)
1384         AbbrevToUse = CString7Abbrev;
1385     } else if (const ConstantDataSequential *CDS =
1386                   dyn_cast<ConstantDataSequential>(C)) {
1387       Code = bitc::CST_CODE_DATA;
1388       Type *EltTy = CDS->getType()->getElementType();
1389       if (isa<IntegerType>(EltTy)) {
1390         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1391           Record.push_back(CDS->getElementAsInteger(i));
1392       } else if (EltTy->isFloatTy()) {
1393         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1394           union { float F; uint32_t I; };
1395           F = CDS->getElementAsFloat(i);
1396           Record.push_back(I);
1397         }
1398       } else {
1399         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1400         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1401           union { double F; uint64_t I; };
1402           F = CDS->getElementAsDouble(i);
1403           Record.push_back(I);
1404         }
1405       }
1406     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1407                isa<ConstantVector>(C)) {
1408       Code = bitc::CST_CODE_AGGREGATE;
1409       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1410         Record.push_back(VE.getValueID(C->getOperand(i)));
1411       AbbrevToUse = AggregateAbbrev;
1412     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1413       switch (CE->getOpcode()) {
1414       default:
1415         if (Instruction::isCast(CE->getOpcode())) {
1416           Code = bitc::CST_CODE_CE_CAST;
1417           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1418           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1419           Record.push_back(VE.getValueID(C->getOperand(0)));
1420           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1421         } else {
1422           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1423           Code = bitc::CST_CODE_CE_BINOP;
1424           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1425           Record.push_back(VE.getValueID(C->getOperand(0)));
1426           Record.push_back(VE.getValueID(C->getOperand(1)));
1427           uint64_t Flags = GetOptimizationFlags(CE);
1428           if (Flags != 0)
1429             Record.push_back(Flags);
1430         }
1431         break;
1432       case Instruction::GetElementPtr:
1433         Code = bitc::CST_CODE_CE_GEP;
1434         if (cast<GEPOperator>(C)->isInBounds())
1435           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1436         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1437           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1438           Record.push_back(VE.getValueID(C->getOperand(i)));
1439         }
1440         break;
1441       case Instruction::Select:
1442         Code = bitc::CST_CODE_CE_SELECT;
1443         Record.push_back(VE.getValueID(C->getOperand(0)));
1444         Record.push_back(VE.getValueID(C->getOperand(1)));
1445         Record.push_back(VE.getValueID(C->getOperand(2)));
1446         break;
1447       case Instruction::ExtractElement:
1448         Code = bitc::CST_CODE_CE_EXTRACTELT;
1449         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1450         Record.push_back(VE.getValueID(C->getOperand(0)));
1451         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1452         Record.push_back(VE.getValueID(C->getOperand(1)));
1453         break;
1454       case Instruction::InsertElement:
1455         Code = bitc::CST_CODE_CE_INSERTELT;
1456         Record.push_back(VE.getValueID(C->getOperand(0)));
1457         Record.push_back(VE.getValueID(C->getOperand(1)));
1458         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1459         Record.push_back(VE.getValueID(C->getOperand(2)));
1460         break;
1461       case Instruction::ShuffleVector:
1462         // If the return type and argument types are the same, this is a
1463         // standard shufflevector instruction.  If the types are different,
1464         // then the shuffle is widening or truncating the input vectors, and
1465         // the argument type must also be encoded.
1466         if (C->getType() == C->getOperand(0)->getType()) {
1467           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1468         } else {
1469           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1470           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1471         }
1472         Record.push_back(VE.getValueID(C->getOperand(0)));
1473         Record.push_back(VE.getValueID(C->getOperand(1)));
1474         Record.push_back(VE.getValueID(C->getOperand(2)));
1475         break;
1476       case Instruction::ICmp:
1477       case Instruction::FCmp:
1478         Code = bitc::CST_CODE_CE_CMP;
1479         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1480         Record.push_back(VE.getValueID(C->getOperand(0)));
1481         Record.push_back(VE.getValueID(C->getOperand(1)));
1482         Record.push_back(CE->getPredicate());
1483         break;
1484       }
1485     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1486       Code = bitc::CST_CODE_BLOCKADDRESS;
1487       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1488       Record.push_back(VE.getValueID(BA->getFunction()));
1489       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1490     } else {
1491 #ifndef NDEBUG
1492       C->dump();
1493 #endif
1494       llvm_unreachable("Unknown constant!");
1495     }
1496     Stream.EmitRecord(Code, Record, AbbrevToUse);
1497     Record.clear();
1498   }
1499
1500   Stream.ExitBlock();
1501 }
1502
1503 static void WriteModuleConstants(const ValueEnumerator &VE,
1504                                  BitstreamWriter &Stream) {
1505   const ValueEnumerator::ValueList &Vals = VE.getValues();
1506
1507   // Find the first constant to emit, which is the first non-globalvalue value.
1508   // We know globalvalues have been emitted by WriteModuleInfo.
1509   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1510     if (!isa<GlobalValue>(Vals[i].first)) {
1511       WriteConstants(i, Vals.size(), VE, Stream, true);
1512       return;
1513     }
1514   }
1515 }
1516
1517 /// PushValueAndType - The file has to encode both the value and type id for
1518 /// many values, because we need to know what type to create for forward
1519 /// references.  However, most operands are not forward references, so this type
1520 /// field is not needed.
1521 ///
1522 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1523 /// instruction ID, then it is a forward reference, and it also includes the
1524 /// type ID.  The value ID that is written is encoded relative to the InstID.
1525 static bool PushValueAndType(const Value *V, unsigned InstID,
1526                              SmallVectorImpl<unsigned> &Vals,
1527                              ValueEnumerator &VE) {
1528   unsigned ValID = VE.getValueID(V);
1529   // Make encoding relative to the InstID.
1530   Vals.push_back(InstID - ValID);
1531   if (ValID >= InstID) {
1532     Vals.push_back(VE.getTypeID(V->getType()));
1533     return true;
1534   }
1535   return false;
1536 }
1537
1538 /// pushValue - Like PushValueAndType, but where the type of the value is
1539 /// omitted (perhaps it was already encoded in an earlier operand).
1540 static void pushValue(const Value *V, unsigned InstID,
1541                       SmallVectorImpl<unsigned> &Vals,
1542                       ValueEnumerator &VE) {
1543   unsigned ValID = VE.getValueID(V);
1544   Vals.push_back(InstID - ValID);
1545 }
1546
1547 static void pushValueSigned(const Value *V, unsigned InstID,
1548                             SmallVectorImpl<uint64_t> &Vals,
1549                             ValueEnumerator &VE) {
1550   unsigned ValID = VE.getValueID(V);
1551   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1552   emitSignedInt64(Vals, diff);
1553 }
1554
1555 /// WriteInstruction - Emit an instruction to the specified stream.
1556 static void WriteInstruction(const Instruction &I, unsigned InstID,
1557                              ValueEnumerator &VE, BitstreamWriter &Stream,
1558                              SmallVectorImpl<unsigned> &Vals) {
1559   unsigned Code = 0;
1560   unsigned AbbrevToUse = 0;
1561   VE.setInstructionID(&I);
1562   switch (I.getOpcode()) {
1563   default:
1564     if (Instruction::isCast(I.getOpcode())) {
1565       Code = bitc::FUNC_CODE_INST_CAST;
1566       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1567         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1568       Vals.push_back(VE.getTypeID(I.getType()));
1569       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1570     } else {
1571       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1572       Code = bitc::FUNC_CODE_INST_BINOP;
1573       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1574         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1575       pushValue(I.getOperand(1), InstID, Vals, VE);
1576       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1577       uint64_t Flags = GetOptimizationFlags(&I);
1578       if (Flags != 0) {
1579         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1580           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1581         Vals.push_back(Flags);
1582       }
1583     }
1584     break;
1585
1586   case Instruction::GetElementPtr:
1587     Code = bitc::FUNC_CODE_INST_GEP;
1588     if (cast<GEPOperator>(&I)->isInBounds())
1589       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1590     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1591       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1592     break;
1593   case Instruction::ExtractValue: {
1594     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1595     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1596     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1597     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1598       Vals.push_back(*i);
1599     break;
1600   }
1601   case Instruction::InsertValue: {
1602     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1603     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1604     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1605     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1606     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1607       Vals.push_back(*i);
1608     break;
1609   }
1610   case Instruction::Select:
1611     Code = bitc::FUNC_CODE_INST_VSELECT;
1612     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1613     pushValue(I.getOperand(2), InstID, Vals, VE);
1614     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1615     break;
1616   case Instruction::ExtractElement:
1617     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1618     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1619     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1620     break;
1621   case Instruction::InsertElement:
1622     Code = bitc::FUNC_CODE_INST_INSERTELT;
1623     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1624     pushValue(I.getOperand(1), InstID, Vals, VE);
1625     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1626     break;
1627   case Instruction::ShuffleVector:
1628     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1629     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1630     pushValue(I.getOperand(1), InstID, Vals, VE);
1631     pushValue(I.getOperand(2), InstID, Vals, VE);
1632     break;
1633   case Instruction::ICmp:
1634   case Instruction::FCmp:
1635     // compare returning Int1Ty or vector of Int1Ty
1636     Code = bitc::FUNC_CODE_INST_CMP2;
1637     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1638     pushValue(I.getOperand(1), InstID, Vals, VE);
1639     Vals.push_back(cast<CmpInst>(I).getPredicate());
1640     break;
1641
1642   case Instruction::Ret:
1643     {
1644       Code = bitc::FUNC_CODE_INST_RET;
1645       unsigned NumOperands = I.getNumOperands();
1646       if (NumOperands == 0)
1647         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1648       else if (NumOperands == 1) {
1649         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1650           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1651       } else {
1652         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1653           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1654       }
1655     }
1656     break;
1657   case Instruction::Br:
1658     {
1659       Code = bitc::FUNC_CODE_INST_BR;
1660       const BranchInst &II = cast<BranchInst>(I);
1661       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1662       if (II.isConditional()) {
1663         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1664         pushValue(II.getCondition(), InstID, Vals, VE);
1665       }
1666     }
1667     break;
1668   case Instruction::Switch:
1669     {
1670       Code = bitc::FUNC_CODE_INST_SWITCH;
1671       const SwitchInst &SI = cast<SwitchInst>(I);
1672       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1673       pushValue(SI.getCondition(), InstID, Vals, VE);
1674       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1675       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1676            i != e; ++i) {
1677         Vals.push_back(VE.getValueID(i.getCaseValue()));
1678         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1679       }
1680     }
1681     break;
1682   case Instruction::IndirectBr:
1683     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1684     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1685     // Encode the address operand as relative, but not the basic blocks.
1686     pushValue(I.getOperand(0), InstID, Vals, VE);
1687     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1688       Vals.push_back(VE.getValueID(I.getOperand(i)));
1689     break;
1690
1691   case Instruction::Invoke: {
1692     const InvokeInst *II = cast<InvokeInst>(&I);
1693     const Value *Callee(II->getCalledValue());
1694     PointerType *PTy = cast<PointerType>(Callee->getType());
1695     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1696     Code = bitc::FUNC_CODE_INST_INVOKE;
1697
1698     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1699     Vals.push_back(II->getCallingConv());
1700     Vals.push_back(VE.getValueID(II->getNormalDest()));
1701     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1702     PushValueAndType(Callee, InstID, Vals, VE);
1703
1704     // Emit value #'s for the fixed parameters.
1705     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1706       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1707
1708     // Emit type/value pairs for varargs params.
1709     if (FTy->isVarArg()) {
1710       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1711            i != e; ++i)
1712         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1713     }
1714     break;
1715   }
1716   case Instruction::Resume:
1717     Code = bitc::FUNC_CODE_INST_RESUME;
1718     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1719     break;
1720   case Instruction::Unreachable:
1721     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1722     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1723     break;
1724
1725   case Instruction::PHI: {
1726     const PHINode &PN = cast<PHINode>(I);
1727     Code = bitc::FUNC_CODE_INST_PHI;
1728     // With the newer instruction encoding, forward references could give
1729     // negative valued IDs.  This is most common for PHIs, so we use
1730     // signed VBRs.
1731     SmallVector<uint64_t, 128> Vals64;
1732     Vals64.push_back(VE.getTypeID(PN.getType()));
1733     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1734       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1735       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1736     }
1737     // Emit a Vals64 vector and exit.
1738     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1739     Vals64.clear();
1740     return;
1741   }
1742
1743   case Instruction::LandingPad: {
1744     const LandingPadInst &LP = cast<LandingPadInst>(I);
1745     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1746     Vals.push_back(VE.getTypeID(LP.getType()));
1747     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1748     Vals.push_back(LP.isCleanup());
1749     Vals.push_back(LP.getNumClauses());
1750     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1751       if (LP.isCatch(I))
1752         Vals.push_back(LandingPadInst::Catch);
1753       else
1754         Vals.push_back(LandingPadInst::Filter);
1755       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1756     }
1757     break;
1758   }
1759
1760   case Instruction::Alloca: {
1761     Code = bitc::FUNC_CODE_INST_ALLOCA;
1762     Vals.push_back(VE.getTypeID(I.getType()));
1763     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1764     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1765     const AllocaInst &AI = cast<AllocaInst>(I);
1766     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1767     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1768            "not enough bits for maximum alignment");
1769     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1770     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1771     Vals.push_back(AlignRecord);
1772     break;
1773   }
1774
1775   case Instruction::Load:
1776     if (cast<LoadInst>(I).isAtomic()) {
1777       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1778       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1779     } else {
1780       Code = bitc::FUNC_CODE_INST_LOAD;
1781       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1782         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1783     }
1784     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1785     Vals.push_back(cast<LoadInst>(I).isVolatile());
1786     if (cast<LoadInst>(I).isAtomic()) {
1787       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1788       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1789     }
1790     break;
1791   case Instruction::Store:
1792     if (cast<StoreInst>(I).isAtomic())
1793       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1794     else
1795       Code = bitc::FUNC_CODE_INST_STORE;
1796     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1797     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1798     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1799     Vals.push_back(cast<StoreInst>(I).isVolatile());
1800     if (cast<StoreInst>(I).isAtomic()) {
1801       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1802       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1803     }
1804     break;
1805   case Instruction::AtomicCmpXchg:
1806     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1807     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1808     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1809     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1810     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1811     Vals.push_back(GetEncodedOrdering(
1812                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1813     Vals.push_back(GetEncodedSynchScope(
1814                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1815     Vals.push_back(GetEncodedOrdering(
1816                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1817     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1818     break;
1819   case Instruction::AtomicRMW:
1820     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1821     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1822     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1823     Vals.push_back(GetEncodedRMWOperation(
1824                      cast<AtomicRMWInst>(I).getOperation()));
1825     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1826     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1827     Vals.push_back(GetEncodedSynchScope(
1828                      cast<AtomicRMWInst>(I).getSynchScope()));
1829     break;
1830   case Instruction::Fence:
1831     Code = bitc::FUNC_CODE_INST_FENCE;
1832     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1833     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1834     break;
1835   case Instruction::Call: {
1836     const CallInst &CI = cast<CallInst>(I);
1837     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1838     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1839
1840     Code = bitc::FUNC_CODE_INST_CALL;
1841
1842     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1843     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1844                    unsigned(CI.isMustTailCall()) << 14);
1845     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1846
1847     // Emit value #'s for the fixed parameters.
1848     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1849       // Check for labels (can happen with asm labels).
1850       if (FTy->getParamType(i)->isLabelTy())
1851         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1852       else
1853         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1854     }
1855
1856     // Emit type/value pairs for varargs params.
1857     if (FTy->isVarArg()) {
1858       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1859            i != e; ++i)
1860         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1861     }
1862     break;
1863   }
1864   case Instruction::VAArg:
1865     Code = bitc::FUNC_CODE_INST_VAARG;
1866     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1867     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1868     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1869     break;
1870   }
1871
1872   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1873   Vals.clear();
1874 }
1875
1876 // Emit names for globals/functions etc.
1877 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1878                                   const ValueEnumerator &VE,
1879                                   BitstreamWriter &Stream) {
1880   if (VST.empty()) return;
1881   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1882
1883   // FIXME: Set up the abbrev, we know how many values there are!
1884   // FIXME: We know if the type names can use 7-bit ascii.
1885   SmallVector<unsigned, 64> NameVals;
1886
1887   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1888        SI != SE; ++SI) {
1889
1890     const ValueName &Name = *SI;
1891
1892     // Figure out the encoding to use for the name.
1893     bool is7Bit = true;
1894     bool isChar6 = true;
1895     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1896          C != E; ++C) {
1897       if (isChar6)
1898         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1899       if ((unsigned char)*C & 128) {
1900         is7Bit = false;
1901         break;  // don't bother scanning the rest.
1902       }
1903     }
1904
1905     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1906
1907     // VST_ENTRY:   [valueid, namechar x N]
1908     // VST_BBENTRY: [bbid, namechar x N]
1909     unsigned Code;
1910     if (isa<BasicBlock>(SI->getValue())) {
1911       Code = bitc::VST_CODE_BBENTRY;
1912       if (isChar6)
1913         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1914     } else {
1915       Code = bitc::VST_CODE_ENTRY;
1916       if (isChar6)
1917         AbbrevToUse = VST_ENTRY_6_ABBREV;
1918       else if (is7Bit)
1919         AbbrevToUse = VST_ENTRY_7_ABBREV;
1920     }
1921
1922     NameVals.push_back(VE.getValueID(SI->getValue()));
1923     for (const char *P = Name.getKeyData(),
1924          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1925       NameVals.push_back((unsigned char)*P);
1926
1927     // Emit the finished record.
1928     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1929     NameVals.clear();
1930   }
1931   Stream.ExitBlock();
1932 }
1933
1934 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1935                          BitstreamWriter &Stream) {
1936   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1937   unsigned Code;
1938   if (isa<BasicBlock>(Order.V))
1939     Code = bitc::USELIST_CODE_BB;
1940   else
1941     Code = bitc::USELIST_CODE_DEFAULT;
1942
1943   SmallVector<uint64_t, 64> Record;
1944   for (unsigned I : Order.Shuffle)
1945     Record.push_back(I);
1946   Record.push_back(VE.getValueID(Order.V));
1947   Stream.EmitRecord(Code, Record);
1948 }
1949
1950 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1951                               BitstreamWriter &Stream) {
1952   auto hasMore = [&]() {
1953     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1954   };
1955   if (!hasMore())
1956     // Nothing to do.
1957     return;
1958
1959   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1960   while (hasMore()) {
1961     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1962     VE.UseListOrders.pop_back();
1963   }
1964   Stream.ExitBlock();
1965 }
1966
1967 /// WriteFunction - Emit a function body to the module stream.
1968 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1969                           BitstreamWriter &Stream) {
1970   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1971   VE.incorporateFunction(F);
1972
1973   SmallVector<unsigned, 64> Vals;
1974
1975   // Emit the number of basic blocks, so the reader can create them ahead of
1976   // time.
1977   Vals.push_back(VE.getBasicBlocks().size());
1978   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1979   Vals.clear();
1980
1981   // If there are function-local constants, emit them now.
1982   unsigned CstStart, CstEnd;
1983   VE.getFunctionConstantRange(CstStart, CstEnd);
1984   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1985
1986   // If there is function-local metadata, emit it now.
1987   WriteFunctionLocalMetadata(F, VE, Stream);
1988
1989   // Keep a running idea of what the instruction ID is.
1990   unsigned InstID = CstEnd;
1991
1992   bool NeedsMetadataAttachment = false;
1993
1994   DebugLoc LastDL;
1995
1996   // Finally, emit all the instructions, in order.
1997   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1998     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1999          I != E; ++I) {
2000       WriteInstruction(*I, InstID, VE, Stream, Vals);
2001
2002       if (!I->getType()->isVoidTy())
2003         ++InstID;
2004
2005       // If the instruction has metadata, write a metadata attachment later.
2006       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2007
2008       // If the instruction has a debug location, emit it.
2009       DebugLoc DL = I->getDebugLoc();
2010       if (DL.isUnknown()) {
2011         // nothing todo.
2012       } else if (DL == LastDL) {
2013         // Just repeat the same debug loc as last time.
2014         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2015       } else {
2016         MDNode *Scope, *IA;
2017         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
2018         assert(Scope && "Expected valid scope");
2019
2020         Vals.push_back(DL.getLine());
2021         Vals.push_back(DL.getCol());
2022         Vals.push_back(VE.getMetadataOrNullID(Scope));
2023         Vals.push_back(VE.getMetadataOrNullID(IA));
2024         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2025         Vals.clear();
2026
2027         LastDL = DL;
2028       }
2029     }
2030
2031   // Emit names for all the instructions etc.
2032   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2033
2034   if (NeedsMetadataAttachment)
2035     WriteMetadataAttachment(F, VE, Stream);
2036   if (shouldPreserveBitcodeUseListOrder())
2037     WriteUseListBlock(&F, VE, Stream);
2038   VE.purgeFunction();
2039   Stream.ExitBlock();
2040 }
2041
2042 // Emit blockinfo, which defines the standard abbreviations etc.
2043 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2044   // We only want to emit block info records for blocks that have multiple
2045   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2046   // Other blocks can define their abbrevs inline.
2047   Stream.EnterBlockInfoBlock(2);
2048
2049   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2050     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2051     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2052     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2053     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2054     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2055     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2056                                    Abbv) != VST_ENTRY_8_ABBREV)
2057       llvm_unreachable("Unexpected abbrev ordering!");
2058   }
2059
2060   { // 7-bit fixed width VST_ENTRY strings.
2061     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2062     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2063     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2064     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2065     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2066     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2067                                    Abbv) != VST_ENTRY_7_ABBREV)
2068       llvm_unreachable("Unexpected abbrev ordering!");
2069   }
2070   { // 6-bit char6 VST_ENTRY strings.
2071     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2072     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2073     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2074     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2075     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2076     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2077                                    Abbv) != VST_ENTRY_6_ABBREV)
2078       llvm_unreachable("Unexpected abbrev ordering!");
2079   }
2080   { // 6-bit char6 VST_BBENTRY strings.
2081     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2082     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2083     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2084     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2085     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2086     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2087                                    Abbv) != VST_BBENTRY_6_ABBREV)
2088       llvm_unreachable("Unexpected abbrev ordering!");
2089   }
2090
2091
2092
2093   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2094     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2095     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2096     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2097                               Log2_32_Ceil(VE.getTypes().size()+1)));
2098     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2099                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2100       llvm_unreachable("Unexpected abbrev ordering!");
2101   }
2102
2103   { // INTEGER abbrev for CONSTANTS_BLOCK.
2104     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2105     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2106     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2107     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2108                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2109       llvm_unreachable("Unexpected abbrev ordering!");
2110   }
2111
2112   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2113     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2114     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2115     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2116     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2117                               Log2_32_Ceil(VE.getTypes().size()+1)));
2118     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2119
2120     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2121                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2122       llvm_unreachable("Unexpected abbrev ordering!");
2123   }
2124   { // NULL abbrev for CONSTANTS_BLOCK.
2125     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2126     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2127     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2128                                    Abbv) != CONSTANTS_NULL_Abbrev)
2129       llvm_unreachable("Unexpected abbrev ordering!");
2130   }
2131
2132   // FIXME: This should only use space for first class types!
2133
2134   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2135     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2136     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2138     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2139     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2140     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2141                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2142       llvm_unreachable("Unexpected abbrev ordering!");
2143   }
2144   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2145     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2146     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2150     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2151                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2152       llvm_unreachable("Unexpected abbrev ordering!");
2153   }
2154   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2155     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2156     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2159     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2161     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2162                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2163       llvm_unreachable("Unexpected abbrev ordering!");
2164   }
2165   { // INST_CAST abbrev for FUNCTION_BLOCK.
2166     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2167     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2170                               Log2_32_Ceil(VE.getTypes().size()+1)));
2171     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2172     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2173                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2174       llvm_unreachable("Unexpected abbrev ordering!");
2175   }
2176
2177   { // INST_RET abbrev for FUNCTION_BLOCK.
2178     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2179     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2180     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2181                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2182       llvm_unreachable("Unexpected abbrev ordering!");
2183   }
2184   { // INST_RET abbrev for FUNCTION_BLOCK.
2185     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2186     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2188     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2189                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2190       llvm_unreachable("Unexpected abbrev ordering!");
2191   }
2192   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2193     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2194     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2195     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2196                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2197       llvm_unreachable("Unexpected abbrev ordering!");
2198   }
2199
2200   Stream.ExitBlock();
2201 }
2202
2203 /// WriteModule - Emit the specified module to the bitstream.
2204 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2205   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2206
2207   SmallVector<unsigned, 1> Vals;
2208   unsigned CurVersion = 1;
2209   Vals.push_back(CurVersion);
2210   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2211
2212   // Analyze the module, enumerating globals, functions, etc.
2213   ValueEnumerator VE(*M);
2214
2215   // Emit blockinfo, which defines the standard abbreviations etc.
2216   WriteBlockInfo(VE, Stream);
2217
2218   // Emit information about attribute groups.
2219   WriteAttributeGroupTable(VE, Stream);
2220
2221   // Emit information about parameter attributes.
2222   WriteAttributeTable(VE, Stream);
2223
2224   // Emit information describing all of the types in the module.
2225   WriteTypeTable(VE, Stream);
2226
2227   writeComdats(VE, Stream);
2228
2229   // Emit top-level description of module, including target triple, inline asm,
2230   // descriptors for global variables, and function prototype info.
2231   WriteModuleInfo(M, VE, Stream);
2232
2233   // Emit constants.
2234   WriteModuleConstants(VE, Stream);
2235
2236   // Emit metadata.
2237   WriteModuleMetadata(M, VE, Stream);
2238
2239   // Emit metadata.
2240   WriteModuleMetadataStore(M, Stream);
2241
2242   // Emit names for globals/functions etc.
2243   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2244
2245   // Emit module-level use-lists.
2246   if (shouldPreserveBitcodeUseListOrder())
2247     WriteUseListBlock(nullptr, VE, Stream);
2248
2249   // Emit function bodies.
2250   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2251     if (!F->isDeclaration())
2252       WriteFunction(*F, VE, Stream);
2253
2254   Stream.ExitBlock();
2255 }
2256
2257 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2258 /// header and trailer to make it compatible with the system archiver.  To do
2259 /// this we emit the following header, and then emit a trailer that pads the
2260 /// file out to be a multiple of 16 bytes.
2261 ///
2262 /// struct bc_header {
2263 ///   uint32_t Magic;         // 0x0B17C0DE
2264 ///   uint32_t Version;       // Version, currently always 0.
2265 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2266 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2267 ///   uint32_t CPUType;       // CPU specifier.
2268 ///   ... potentially more later ...
2269 /// };
2270 enum {
2271   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2272   DarwinBCHeaderSize = 5*4
2273 };
2274
2275 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2276                                uint32_t &Position) {
2277   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2278   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2279   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2280   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2281   Position += 4;
2282 }
2283
2284 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2285                                          const Triple &TT) {
2286   unsigned CPUType = ~0U;
2287
2288   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2289   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2290   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2291   // specific constants here because they are implicitly part of the Darwin ABI.
2292   enum {
2293     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2294     DARWIN_CPU_TYPE_X86        = 7,
2295     DARWIN_CPU_TYPE_ARM        = 12,
2296     DARWIN_CPU_TYPE_POWERPC    = 18
2297   };
2298
2299   Triple::ArchType Arch = TT.getArch();
2300   if (Arch == Triple::x86_64)
2301     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2302   else if (Arch == Triple::x86)
2303     CPUType = DARWIN_CPU_TYPE_X86;
2304   else if (Arch == Triple::ppc)
2305     CPUType = DARWIN_CPU_TYPE_POWERPC;
2306   else if (Arch == Triple::ppc64)
2307     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2308   else if (Arch == Triple::arm || Arch == Triple::thumb)
2309     CPUType = DARWIN_CPU_TYPE_ARM;
2310
2311   // Traditional Bitcode starts after header.
2312   assert(Buffer.size() >= DarwinBCHeaderSize &&
2313          "Expected header size to be reserved");
2314   unsigned BCOffset = DarwinBCHeaderSize;
2315   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2316
2317   // Write the magic and version.
2318   unsigned Position = 0;
2319   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2320   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2321   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2322   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2323   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2324
2325   // If the file is not a multiple of 16 bytes, insert dummy padding.
2326   while (Buffer.size() & 15)
2327     Buffer.push_back(0);
2328 }
2329
2330 /// WriteBitcodeToFile - Write the specified module to the specified output
2331 /// stream.
2332 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2333   SmallVector<char, 0> Buffer;
2334   Buffer.reserve(256*1024);
2335
2336   // If this is darwin or another generic macho target, reserve space for the
2337   // header.
2338   Triple TT(M->getTargetTriple());
2339   if (TT.isOSDarwin())
2340     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2341
2342   // Emit the module into the buffer.
2343   {
2344     BitstreamWriter Stream(Buffer);
2345
2346     // Emit the file header.
2347     Stream.Emit((unsigned)'B', 8);
2348     Stream.Emit((unsigned)'C', 8);
2349     Stream.Emit(0x0, 4);
2350     Stream.Emit(0xC, 4);
2351     Stream.Emit(0xE, 4);
2352     Stream.Emit(0xD, 4);
2353
2354     // Emit the module.
2355     WriteModule(M, Stream);
2356   }
2357
2358   if (TT.isOSDarwin())
2359     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2360
2361   // Write the generated bitstream to "Out".
2362   Out.write((char*)&Buffer.front(), Buffer.size());
2363 }