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   FUNCTION_INST_GEP_ABBREV,
  61 };
  62
  63 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  64   switch (Opcode) {
  65   default: llvm_unreachable("Unknown cast instruction!");
  66   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  67   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  68   case Instruction::SExt    : return bitc::CAST_SEXT;
  69   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  70   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  71   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  72   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  73   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  74   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  75   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  76   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  77   case Instruction::BitCast : return bitc::CAST_BITCAST;
  78   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  79   }
  80 }
  81
  82 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  83   switch (Opcode) {
  84   default: llvm_unreachable("Unknown binary instruction!");
  85   case Instruction::Add:
  86   case Instruction::FAdd: return bitc::BINOP_ADD;
  87   case Instruction::Sub:
  88   case Instruction::FSub: return bitc::BINOP_SUB;
  89   case Instruction::Mul:
  90   case Instruction::FMul: return bitc::BINOP_MUL;
  91   case Instruction::UDiv: return bitc::BINOP_UDIV;
  92   case Instruction::FDiv:
  93   case Instruction::SDiv: return bitc::BINOP_SDIV;
  94   case Instruction::URem: return bitc::BINOP_UREM;
  95   case Instruction::FRem:
  96   case Instruction::SRem: return bitc::BINOP_SREM;
  97   case Instruction::Shl:  return bitc::BINOP_SHL;
  98   case Instruction::LShr: return bitc::BINOP_LSHR;
  99   case Instruction::AShr: return bitc::BINOP_ASHR;
 100   case Instruction::And:  return bitc::BINOP_AND;
 101   case Instruction::Or:   return bitc::BINOP_OR;
 102   case Instruction::Xor:  return bitc::BINOP_XOR;
 103   }
 104 }
 105
 106 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 107   switch (Op) {
 108   default: llvm_unreachable("Unknown RMW operation!");
 109   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 110   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 111   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 112   case AtomicRMWInst::And: return bitc::RMW_AND;
 113   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 114   case AtomicRMWInst::Or: return bitc::RMW_OR;
 115   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 116   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 117   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 118   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 119   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 120   }
 121 }
 122
 123 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 124   switch (Ordering) {
 125   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 126   case Unordered: return bitc::ORDERING_UNORDERED;
 127   case Monotonic: return bitc::ORDERING_MONOTONIC;
 128   case Acquire: return bitc::ORDERING_ACQUIRE;
 129   case Release: return bitc::ORDERING_RELEASE;
 130   case AcquireRelease: return bitc::ORDERING_ACQREL;
 131   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 132   }
 133   llvm_unreachable("Invalid ordering");
 134 }
 135
 136 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 137   switch (SynchScope) {
 138   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 139   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 140   }
 141   llvm_unreachable("Invalid synch scope");
 142 }
 143
 144 static void WriteStringRecord(unsigned Code, StringRef Str,
 145                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 146   SmallVector<unsigned, 64> Vals;
 147
 148   // Code: [strchar x N]
 149   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 150     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 151       AbbrevToUse = 0;
 152     Vals.push_back(Str[i]);
 153   }
 154
 155   // Emit the finished record.
 156   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 157 }
 158
 159 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 160   switch (Kind) {
 161   case Attribute::Alignment:
 162     return bitc::ATTR_KIND_ALIGNMENT;
 163   case Attribute::AlwaysInline:
 164     return bitc::ATTR_KIND_ALWAYS_INLINE;
 165   case Attribute::Builtin:
 166     return bitc::ATTR_KIND_BUILTIN;
 167   case Attribute::ByVal:
 168     return bitc::ATTR_KIND_BY_VAL;
 169   case Attribute::InAlloca:
 170     return bitc::ATTR_KIND_IN_ALLOCA;
 171   case Attribute::Cold:
 172     return bitc::ATTR_KIND_COLD;
 173   case Attribute::InlineHint:
 174     return bitc::ATTR_KIND_INLINE_HINT;
 175   case Attribute::InReg:
 176     return bitc::ATTR_KIND_IN_REG;
 177   case Attribute::JumpTable:
 178     return bitc::ATTR_KIND_JUMP_TABLE;
 179   case Attribute::MinSize:
 180     return bitc::ATTR_KIND_MIN_SIZE;
 181   case Attribute::Naked:
 182     return bitc::ATTR_KIND_NAKED;
 183   case Attribute::Nest:
 184     return bitc::ATTR_KIND_NEST;
 185   case Attribute::NoAlias:
 186     return bitc::ATTR_KIND_NO_ALIAS;
 187   case Attribute::NoBuiltin:
 188     return bitc::ATTR_KIND_NO_BUILTIN;
 189   case Attribute::NoCapture:
 190     return bitc::ATTR_KIND_NO_CAPTURE;
 191   case Attribute::NoDuplicate:
 192     return bitc::ATTR_KIND_NO_DUPLICATE;
 193   case Attribute::NoImplicitFloat:
 194     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 195   case Attribute::NoInline:
 196     return bitc::ATTR_KIND_NO_INLINE;
 197   case Attribute::NonLazyBind:
 198     return bitc::ATTR_KIND_NON_LAZY_BIND;
 199   case Attribute::NonNull:
 200     return bitc::ATTR_KIND_NON_NULL;
 201   case Attribute::Dereferenceable:
 202     return bitc::ATTR_KIND_DEREFERENCEABLE;
 203   case Attribute::DereferenceableOrNull:
 204     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 205   case Attribute::NoRedZone:
 206     return bitc::ATTR_KIND_NO_RED_ZONE;
 207   case Attribute::NoReturn:
 208     return bitc::ATTR_KIND_NO_RETURN;
 209   case Attribute::NoUnwind:
 210     return bitc::ATTR_KIND_NO_UNWIND;
 211   case Attribute::OptimizeForSize:
 212     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 213   case Attribute::OptimizeNone:
 214     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 215   case Attribute::ReadNone:
 216     return bitc::ATTR_KIND_READ_NONE;
 217   case Attribute::ReadOnly:
 218     return bitc::ATTR_KIND_READ_ONLY;
 219   case Attribute::Returned:
 220     return bitc::ATTR_KIND_RETURNED;
 221   case Attribute::ReturnsTwice:
 222     return bitc::ATTR_KIND_RETURNS_TWICE;
 223   case Attribute::SExt:
 224     return bitc::ATTR_KIND_S_EXT;
 225   case Attribute::StackAlignment:
 226     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 227   case Attribute::StackProtect:
 228     return bitc::ATTR_KIND_STACK_PROTECT;
 229   case Attribute::StackProtectReq:
 230     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 231   case Attribute::StackProtectStrong:
 232     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 233   case Attribute::StructRet:
 234     return bitc::ATTR_KIND_STRUCT_RET;
 235   case Attribute::SanitizeAddress:
 236     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 237   case Attribute::SanitizeThread:
 238     return bitc::ATTR_KIND_SANITIZE_THREAD;
 239   case Attribute::SanitizeMemory:
 240     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 241   case Attribute::UWTable:
 242     return bitc::ATTR_KIND_UW_TABLE;
 243   case Attribute::ZExt:
 244     return bitc::ATTR_KIND_Z_EXT;
 245   case Attribute::EndAttrKinds:
 246     llvm_unreachable("Can not encode end-attribute kinds marker.");
 247   case Attribute::None:
 248     llvm_unreachable("Can not encode none-attribute.");
 249   }
 250
 251   llvm_unreachable("Trying to encode unknown attribute");
 252 }
 253
 254 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 255                                      BitstreamWriter &Stream) {
 256   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 257   if (AttrGrps.empty()) return;
 258
 259   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 260
 261   SmallVector<uint64_t, 64> Record;
 262   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 263     AttributeSet AS = AttrGrps[i];
 264     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 265       AttributeSet A = AS.getSlotAttributes(i);
 266
 267       Record.push_back(VE.getAttributeGroupID(A));
 268       Record.push_back(AS.getSlotIndex(i));
 269
 270       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 271            I != E; ++I) {
 272         Attribute Attr = *I;
 273         if (Attr.isEnumAttribute()) {
 274           Record.push_back(0);
 275           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 276         } else if (Attr.isIntAttribute()) {
 277           Record.push_back(1);
 278           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 279           Record.push_back(Attr.getValueAsInt());
 280         } else {
 281           StringRef Kind = Attr.getKindAsString();
 282           StringRef Val = Attr.getValueAsString();
 283
 284           Record.push_back(Val.empty() ? 3 : 4);
 285           Record.append(Kind.begin(), Kind.end());
 286           Record.push_back(0);
 287           if (!Val.empty()) {
 288             Record.append(Val.begin(), Val.end());
 289             Record.push_back(0);
 290           }
 291         }
 292       }
 293
 294       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 295       Record.clear();
 296     }
 297   }
 298
 299   Stream.ExitBlock();
 300 }
 301
 302 static void WriteAttributeTable(const ValueEnumerator &VE,
 303                                 BitstreamWriter &Stream) {
 304   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 305   if (Attrs.empty()) return;
 306
 307   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 308
 309   SmallVector<uint64_t, 64> Record;
 310   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 311     const AttributeSet &A = Attrs[i];
 312     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 313       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 314
 315     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 316     Record.clear();
 317   }
 318
 319   Stream.ExitBlock();
 320 }
 321
 322 /// WriteTypeTable - Write out the type table for a module.
 323 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 324   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 325
 326   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 327   SmallVector<uint64_t, 64> TypeVals;
 328
 329   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 330
 331   // Abbrev for TYPE_CODE_POINTER.
 332   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 333   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 335   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 336   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 337
 338   // Abbrev for TYPE_CODE_FUNCTION.
 339   Abbv = new BitCodeAbbrev();
 340   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 344
 345   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 346
 347   // Abbrev for TYPE_CODE_STRUCT_ANON.
 348   Abbv = new BitCodeAbbrev();
 349   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 353
 354   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 355
 356   // Abbrev for TYPE_CODE_STRUCT_NAME.
 357   Abbv = new BitCodeAbbrev();
 358   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 361   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 362
 363   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 364   Abbv = new BitCodeAbbrev();
 365   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 369
 370   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 371
 372   // Abbrev for TYPE_CODE_ARRAY.
 373   Abbv = new BitCodeAbbrev();
 374   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 375   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 376   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 377
 378   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 379
 380   // Emit an entry count so the reader can reserve space.
 381   TypeVals.push_back(TypeList.size());
 382   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 383   TypeVals.clear();
 384
 385   // Loop over all of the types, emitting each in turn.
 386   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 387     Type *T = TypeList[i];
 388     int AbbrevToUse = 0;
 389     unsigned Code = 0;
 390
 391     switch (T->getTypeID()) {
 392     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 393     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 394     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 395     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 396     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 397     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 398     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 399     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 400     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 401     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 402     case Type::IntegerTyID:
 403       // INTEGER: [width]
 404       Code = bitc::TYPE_CODE_INTEGER;
 405       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 406       break;
 407     case Type::PointerTyID: {
 408       PointerType *PTy = cast<PointerType>(T);
 409       // POINTER: [pointee type, address space]
 410       Code = bitc::TYPE_CODE_POINTER;
 411       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 412       unsigned AddressSpace = PTy->getAddressSpace();
 413       TypeVals.push_back(AddressSpace);
 414       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 415       break;
 416     }
 417     case Type::FunctionTyID: {
 418       FunctionType *FT = cast<FunctionType>(T);
 419       // FUNCTION: [isvararg, retty, paramty x N]
 420       Code = bitc::TYPE_CODE_FUNCTION;
 421       TypeVals.push_back(FT->isVarArg());
 422       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 423       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 424         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 425       AbbrevToUse = FunctionAbbrev;
 426       break;
 427     }
 428     case Type::StructTyID: {
 429       StructType *ST = cast<StructType>(T);
 430       // STRUCT: [ispacked, eltty x N]
 431       TypeVals.push_back(ST->isPacked());
 432       // Output all of the element types.
 433       for (StructType::element_iterator I = ST->element_begin(),
 434            E = ST->element_end(); I != E; ++I)
 435         TypeVals.push_back(VE.getTypeID(*I));
 436
 437       if (ST->isLiteral()) {
 438         Code = bitc::TYPE_CODE_STRUCT_ANON;
 439         AbbrevToUse = StructAnonAbbrev;
 440       } else {
 441         if (ST->isOpaque()) {
 442           Code = bitc::TYPE_CODE_OPAQUE;
 443         } else {
 444           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 445           AbbrevToUse = StructNamedAbbrev;
 446         }
 447
 448         // Emit the name if it is present.
 449         if (!ST->getName().empty())
 450           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 451                             StructNameAbbrev, Stream);
 452       }
 453       break;
 454     }
 455     case Type::ArrayTyID: {
 456       ArrayType *AT = cast<ArrayType>(T);
 457       // ARRAY: [numelts, eltty]
 458       Code = bitc::TYPE_CODE_ARRAY;
 459       TypeVals.push_back(AT->getNumElements());
 460       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 461       AbbrevToUse = ArrayAbbrev;
 462       break;
 463     }
 464     case Type::VectorTyID: {
 465       VectorType *VT = cast<VectorType>(T);
 466       // VECTOR [numelts, eltty]
 467       Code = bitc::TYPE_CODE_VECTOR;
 468       TypeVals.push_back(VT->getNumElements());
 469       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 470       break;
 471     }
 472     }
 473
 474     // Emit the finished record.
 475     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 476     TypeVals.clear();
 477   }
 478
 479   Stream.ExitBlock();
 480 }
 481
 482 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 483   switch (GV.getLinkage()) {
 484   case GlobalValue::ExternalLinkage:
 485     return 0;
 486   case GlobalValue::WeakAnyLinkage:
 487     return 16;
 488   case GlobalValue::AppendingLinkage:
 489     return 2;
 490   case GlobalValue::InternalLinkage:
 491     return 3;
 492   case GlobalValue::LinkOnceAnyLinkage:
 493     return 18;
 494   case GlobalValue::ExternalWeakLinkage:
 495     return 7;
 496   case GlobalValue::CommonLinkage:
 497     return 8;
 498   case GlobalValue::PrivateLinkage:
 499     return 9;
 500   case GlobalValue::WeakODRLinkage:
 501     return 17;
 502   case GlobalValue::LinkOnceODRLinkage:
 503     return 19;
 504   case GlobalValue::AvailableExternallyLinkage:
 505     return 12;
 506   }
 507   llvm_unreachable("Invalid linkage");
 508 }
 509
 510 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 511   switch (GV.getVisibility()) {
 512   case GlobalValue::DefaultVisibility:   return 0;
 513   case GlobalValue::HiddenVisibility:    return 1;
 514   case GlobalValue::ProtectedVisibility: return 2;
 515   }
 516   llvm_unreachable("Invalid visibility");
 517 }
 518
 519 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 520   switch (GV.getDLLStorageClass()) {
 521   case GlobalValue::DefaultStorageClass:   return 0;
 522   case GlobalValue::DLLImportStorageClass: return 1;
 523   case GlobalValue::DLLExportStorageClass: return 2;
 524   }
 525   llvm_unreachable("Invalid DLL storage class");
 526 }
 527
 528 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 529   switch (GV.getThreadLocalMode()) {
 530     case GlobalVariable::NotThreadLocal:         return 0;
 531     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 532     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 533     case GlobalVariable::InitialExecTLSModel:    return 3;
 534     case GlobalVariable::LocalExecTLSModel:      return 4;
 535   }
 536   llvm_unreachable("Invalid TLS model");
 537 }
 538
 539 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 540   switch (C.getSelectionKind()) {
 541   case Comdat::Any:
 542     return bitc::COMDAT_SELECTION_KIND_ANY;
 543   case Comdat::ExactMatch:
 544     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 545   case Comdat::Largest:
 546     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 547   case Comdat::NoDuplicates:
 548     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 549   case Comdat::SameSize:
 550     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 551   }
 552   llvm_unreachable("Invalid selection kind");
 553 }
 554
 555 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 556   SmallVector<uint16_t, 64> Vals;
 557   for (const Comdat *C : VE.getComdats()) {
 558     // COMDAT: [selection_kind, name]
 559     Vals.push_back(getEncodedComdatSelectionKind(*C));
 560     size_t Size = C->getName().size();
 561     assert(isUInt<16>(Size));
 562     Vals.push_back(Size);
 563     for (char Chr : C->getName())
 564       Vals.push_back((unsigned char)Chr);
 565     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 566     Vals.clear();
 567   }
 568 }
 569
 570 // Emit top-level description of module, including target triple, inline asm,
 571 // descriptors for global variables, and function prototype info.
 572 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 573                             BitstreamWriter &Stream) {
 574   // Emit various pieces of data attached to a module.
 575   if (!M->getTargetTriple().empty())
 576     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 577                       0/*TODO*/, Stream);
 578   const std::string &DL = M->getDataLayoutStr();
 579   if (!DL.empty())
 580     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 581   if (!M->getModuleInlineAsm().empty())
 582     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 583                       0/*TODO*/, Stream);
 584
 585   // Emit information about sections and GC, computing how many there are. Also
 586   // compute the maximum alignment value.
 587   std::map<std::string, unsigned> SectionMap;
 588   std::map<std::string, unsigned> GCMap;
 589   unsigned MaxAlignment = 0;
 590   unsigned MaxGlobalType = 0;
 591   for (const GlobalValue &GV : M->globals()) {
 592     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 593     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 594     if (GV.hasSection()) {
 595       // Give section names unique ID's.
 596       unsigned &Entry = SectionMap[GV.getSection()];
 597       if (!Entry) {
 598         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 599                           0/*TODO*/, Stream);
 600         Entry = SectionMap.size();
 601       }
 602     }
 603   }
 604   for (const Function &F : *M) {
 605     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 606     if (F.hasSection()) {
 607       // Give section names unique ID's.
 608       unsigned &Entry = SectionMap[F.getSection()];
 609       if (!Entry) {
 610         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 611                           0/*TODO*/, Stream);
 612         Entry = SectionMap.size();
 613       }
 614     }
 615     if (F.hasGC()) {
 616       // Same for GC names.
 617       unsigned &Entry = GCMap[F.getGC()];
 618       if (!Entry) {
 619         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 620                           0/*TODO*/, Stream);
 621         Entry = GCMap.size();
 622       }
 623     }
 624   }
 625
 626   // Emit abbrev for globals, now that we know # sections and max alignment.
 627   unsigned SimpleGVarAbbrev = 0;
 628   if (!M->global_empty()) {
 629     // Add an abbrev for common globals with no visibility or thread localness.
 630     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 631     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 633                               Log2_32_Ceil(MaxGlobalType+1)));
 634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 635                                                            //| explicitType << 1
 636                                                            //| constant
 637     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 638     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 639     if (MaxAlignment == 0)                                 // Alignment.
 640       Abbv->Add(BitCodeAbbrevOp(0));
 641     else {
 642       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 643       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 644                                Log2_32_Ceil(MaxEncAlignment+1)));
 645     }
 646     if (SectionMap.empty())                                    // Section.
 647       Abbv->Add(BitCodeAbbrevOp(0));
 648     else
 649       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 650                                Log2_32_Ceil(SectionMap.size()+1)));
 651     // Don't bother emitting vis + thread local.
 652     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 653   }
 654
 655   // Emit the global variable information.
 656   SmallVector<unsigned, 64> Vals;
 657   for (const GlobalVariable &GV : M->globals()) {
 658     unsigned AbbrevToUse = 0;
 659
 660     // GLOBALVAR: [type, isconst, initid,
 661     //             linkage, alignment, section, visibility, threadlocal,
 662     //             unnamed_addr, externally_initialized, dllstorageclass,
 663     //             comdat]
 664     Vals.push_back(VE.getTypeID(GV.getValueType()));
 665     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 666     Vals.push_back(GV.isDeclaration() ? 0 :
 667                    (VE.getValueID(GV.getInitializer()) + 1));
 668     Vals.push_back(getEncodedLinkage(GV));
 669     Vals.push_back(Log2_32(GV.getAlignment())+1);
 670     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 671     if (GV.isThreadLocal() ||
 672         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 673         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 674         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 675         GV.hasComdat()) {
 676       Vals.push_back(getEncodedVisibility(GV));
 677       Vals.push_back(getEncodedThreadLocalMode(GV));
 678       Vals.push_back(GV.hasUnnamedAddr());
 679       Vals.push_back(GV.isExternallyInitialized());
 680       Vals.push_back(getEncodedDLLStorageClass(GV));
 681       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 682     } else {
 683       AbbrevToUse = SimpleGVarAbbrev;
 684     }
 685
 686     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 687     Vals.clear();
 688   }
 689
 690   // Emit the function proto information.
 691   for (const Function &F : *M) {
 692     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 693     //             section, visibility, gc, unnamed_addr, prologuedata,
 694     //             dllstorageclass, comdat, prefixdata]
 695     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 696     Vals.push_back(F.getCallingConv());
 697     Vals.push_back(F.isDeclaration());
 698     Vals.push_back(getEncodedLinkage(F));
 699     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 700     Vals.push_back(Log2_32(F.getAlignment())+1);
 701     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 702     Vals.push_back(getEncodedVisibility(F));
 703     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 704     Vals.push_back(F.hasUnnamedAddr());
 705     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 706                                        : 0);
 707     Vals.push_back(getEncodedDLLStorageClass(F));
 708     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 709     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 710                                      : 0);
 711
 712     unsigned AbbrevToUse = 0;
 713     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 714     Vals.clear();
 715   }
 716
 717   // Emit the alias information.
 718   for (const GlobalAlias &A : M->aliases()) {
 719     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 720     Vals.push_back(VE.getTypeID(A.getType()));
 721     Vals.push_back(VE.getValueID(A.getAliasee()));
 722     Vals.push_back(getEncodedLinkage(A));
 723     Vals.push_back(getEncodedVisibility(A));
 724     Vals.push_back(getEncodedDLLStorageClass(A));
 725     Vals.push_back(getEncodedThreadLocalMode(A));
 726     Vals.push_back(A.hasUnnamedAddr());
 727     unsigned AbbrevToUse = 0;
 728     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 729     Vals.clear();
 730   }
 731 }
 732
 733 static uint64_t GetOptimizationFlags(const Value *V) {
 734   uint64_t Flags = 0;
 735
 736   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 737     if (OBO->hasNoSignedWrap())
 738       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 739     if (OBO->hasNoUnsignedWrap())
 740       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 741   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 742     if (PEO->isExact())
 743       Flags |= 1 << bitc::PEO_EXACT;
 744   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 745     if (FPMO->hasUnsafeAlgebra())
 746       Flags |= FastMathFlags::UnsafeAlgebra;
 747     if (FPMO->hasNoNaNs())
 748       Flags |= FastMathFlags::NoNaNs;
 749     if (FPMO->hasNoInfs())
 750       Flags |= FastMathFlags::NoInfs;
 751     if (FPMO->hasNoSignedZeros())
 752       Flags |= FastMathFlags::NoSignedZeros;
 753     if (FPMO->hasAllowReciprocal())
 754       Flags |= FastMathFlags::AllowReciprocal;
 755   }
 756
 757   return Flags;
 758 }
 759
 760 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 761                                  const ValueEnumerator &VE,
 762                                  BitstreamWriter &Stream,
 763                                  SmallVectorImpl<uint64_t> &Record) {
 764   // Mimic an MDNode with a value as one operand.
 765   Value *V = MD->getValue();
 766   Record.push_back(VE.getTypeID(V->getType()));
 767   Record.push_back(VE.getValueID(V));
 768   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 769   Record.clear();
 770 }
 771
 772 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 773                          BitstreamWriter &Stream,
 774                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 775   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 776     Metadata *MD = N->getOperand(i);
 777     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 778            "Unexpected function-local metadata");
 779     Record.push_back(VE.getMetadataOrNullID(MD));
 780   }
 781   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 782                                     : bitc::METADATA_NODE,
 783                     Record, Abbrev);
 784   Record.clear();
 785 }
 786
 787 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 788                             BitstreamWriter &Stream,
 789                             SmallVectorImpl<uint64_t> &Record,
 790                             unsigned Abbrev) {
 791   Record.push_back(N->isDistinct());
 792   Record.push_back(N->getLine());
 793   Record.push_back(N->getColumn());
 794   Record.push_back(VE.getMetadataID(N->getScope()));
 795   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 796
 797   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 798   Record.clear();
 799 }
 800
 801 static void WriteGenericDebugNode(const GenericDebugNode *N,
 802                                   const ValueEnumerator &VE,
 803                                   BitstreamWriter &Stream,
 804                                   SmallVectorImpl<uint64_t> &Record,
 805                                   unsigned Abbrev) {
 806   Record.push_back(N->isDistinct());
 807   Record.push_back(N->getTag());
 808   Record.push_back(0); // Per-tag version field; unused for now.
 809
 810   for (auto &I : N->operands())
 811     Record.push_back(VE.getMetadataOrNullID(I));
 812
 813   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 814   Record.clear();
 815 }
 816
 817 static uint64_t rotateSign(int64_t I) {
 818   uint64_t U = I;
 819   return I < 0 ? ~(U << 1) : U << 1;
 820 }
 821
 822 static void WriteMDSubrange(const MDSubrange *N, const ValueEnumerator &,
 823                             BitstreamWriter &Stream,
 824                             SmallVectorImpl<uint64_t> &Record,
 825                             unsigned Abbrev) {
 826   Record.push_back(N->isDistinct());
 827   Record.push_back(N->getCount());
 828   Record.push_back(rotateSign(N->getLowerBound()));
 829
 830   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 831   Record.clear();
 832 }
 833
 834 static void WriteMDEnumerator(const MDEnumerator *N, const ValueEnumerator &VE,
 835                               BitstreamWriter &Stream,
 836                               SmallVectorImpl<uint64_t> &Record,
 837                               unsigned Abbrev) {
 838   Record.push_back(N->isDistinct());
 839   Record.push_back(rotateSign(N->getValue()));
 840   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 841
 842   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 843   Record.clear();
 844 }
 845
 846 static void WriteMDBasicType(const MDBasicType *N, const ValueEnumerator &VE,
 847                              BitstreamWriter &Stream,
 848                              SmallVectorImpl<uint64_t> &Record,
 849                              unsigned Abbrev) {
 850   Record.push_back(N->isDistinct());
 851   Record.push_back(N->getTag());
 852   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 853   Record.push_back(N->getSizeInBits());
 854   Record.push_back(N->getAlignInBits());
 855   Record.push_back(N->getEncoding());
 856
 857   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 858   Record.clear();
 859 }
 860
 861 static void WriteMDDerivedType(const MDDerivedType *N,
 862                                const ValueEnumerator &VE,
 863                                BitstreamWriter &Stream,
 864                                SmallVectorImpl<uint64_t> &Record,
 865                                unsigned Abbrev) {
 866   Record.push_back(N->isDistinct());
 867   Record.push_back(N->getTag());
 868   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 869   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 870   Record.push_back(N->getLine());
 871   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 872   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 873   Record.push_back(N->getSizeInBits());
 874   Record.push_back(N->getAlignInBits());
 875   Record.push_back(N->getOffsetInBits());
 876   Record.push_back(N->getFlags());
 877   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 878
 879   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 880   Record.clear();
 881 }
 882
 883 static void WriteMDCompositeType(const MDCompositeType *N,
 884                                  const ValueEnumerator &VE,
 885                                  BitstreamWriter &Stream,
 886                                  SmallVectorImpl<uint64_t> &Record,
 887                                  unsigned Abbrev) {
 888   Record.push_back(N->isDistinct());
 889   Record.push_back(N->getTag());
 890   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 891   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 892   Record.push_back(N->getLine());
 893   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 894   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 895   Record.push_back(N->getSizeInBits());
 896   Record.push_back(N->getAlignInBits());
 897   Record.push_back(N->getOffsetInBits());
 898   Record.push_back(N->getFlags());
 899   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 900   Record.push_back(N->getRuntimeLang());
 901   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 902   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 903   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 904
 905   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 906   Record.clear();
 907 }
 908
 909 static void WriteMDSubroutineType(const MDSubroutineType *N,
 910                                   const ValueEnumerator &VE,
 911                                   BitstreamWriter &Stream,
 912                                   SmallVectorImpl<uint64_t> &Record,
 913                                   unsigned Abbrev) {
 914   Record.push_back(N->isDistinct());
 915   Record.push_back(N->getFlags());
 916   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 917
 918   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 919   Record.clear();
 920 }
 921
 922 static void WriteMDFile(const MDFile *N, const ValueEnumerator &VE,
 923                         BitstreamWriter &Stream,
 924                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 925   Record.push_back(N->isDistinct());
 926   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 927   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 928
 929   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 930   Record.clear();
 931 }
 932
 933 static void WriteMDCompileUnit(const MDCompileUnit *N,
 934                                const ValueEnumerator &VE,
 935                                BitstreamWriter &Stream,
 936                                SmallVectorImpl<uint64_t> &Record,
 937                                unsigned Abbrev) {
 938   Record.push_back(N->isDistinct());
 939   Record.push_back(N->getSourceLanguage());
 940   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 941   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 942   Record.push_back(N->isOptimized());
 943   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 944   Record.push_back(N->getRuntimeVersion());
 945   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 946   Record.push_back(N->getEmissionKind());
 947   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 948   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 949   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 950   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
 951   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
 952
 953   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 954   Record.clear();
 955 }
 956
 957 static void WriteMDSubprogram(const MDSubprogram *N,
 958                                const ValueEnumerator &VE,
 959                                BitstreamWriter &Stream,
 960                                SmallVectorImpl<uint64_t> &Record,
 961                                unsigned Abbrev) {
 962   Record.push_back(N->isDistinct());
 963   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 964   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 965   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 966   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 967   Record.push_back(N->getLine());
 968   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 969   Record.push_back(N->isLocalToUnit());
 970   Record.push_back(N->isDefinition());
 971   Record.push_back(N->getScopeLine());
 972   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 973   Record.push_back(N->getVirtuality());
 974   Record.push_back(N->getVirtualIndex());
 975   Record.push_back(N->getFlags());
 976   Record.push_back(N->isOptimized());
 977   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
 978   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 979   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 980   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
 981
 982   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 983   Record.clear();
 984 }
 985
 986 static void WriteMDLexicalBlock(const MDLexicalBlock *N,
 987                                const ValueEnumerator &VE,
 988                                BitstreamWriter &Stream,
 989                                SmallVectorImpl<uint64_t> &Record,
 990                                unsigned Abbrev) {
 991   Record.push_back(N->isDistinct());
 992   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 993   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 994   Record.push_back(N->getLine());
 995   Record.push_back(N->getColumn());
 996
 997   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
 998   Record.clear();
 999 }
1000
1001 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *N,
1002                                     const ValueEnumerator &VE,
1003                                     BitstreamWriter &Stream,
1004                                     SmallVectorImpl<uint64_t> &Record,
1005                                     unsigned Abbrev) {
1006   Record.push_back(N->isDistinct());
1007   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1008   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1009   Record.push_back(N->getDiscriminator());
1010
1011   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1012   Record.clear();
1013 }
1014
1015 static void WriteMDNamespace(const MDNamespace *N, const ValueEnumerator &VE,
1016                              BitstreamWriter &Stream,
1017                              SmallVectorImpl<uint64_t> &Record,
1018                              unsigned Abbrev) {
1019   Record.push_back(N->isDistinct());
1020   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1021   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1022   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1023   Record.push_back(N->getLine());
1024
1025   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1026   Record.clear();
1027 }
1028
1029 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *N,
1030                                          const ValueEnumerator &VE,
1031                                          BitstreamWriter &Stream,
1032                                          SmallVectorImpl<uint64_t> &Record,
1033                                          unsigned Abbrev) {
1034   Record.push_back(N->isDistinct());
1035   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1036   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1037
1038   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1039   Record.clear();
1040 }
1041
1042 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *N,
1043                                           const ValueEnumerator &VE,
1044                                           BitstreamWriter &Stream,
1045                                           SmallVectorImpl<uint64_t> &Record,
1046                                           unsigned Abbrev) {
1047   Record.push_back(N->isDistinct());
1048   Record.push_back(N->getTag());
1049   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1050   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1051   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1052
1053   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1054   Record.clear();
1055 }
1056
1057 static void WriteMDGlobalVariable(const MDGlobalVariable *N,
1058                                   const ValueEnumerator &VE,
1059                                   BitstreamWriter &Stream,
1060                                   SmallVectorImpl<uint64_t> &Record,
1061                                   unsigned Abbrev) {
1062   Record.push_back(N->isDistinct());
1063   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1064   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1065   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1066   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1067   Record.push_back(N->getLine());
1068   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1069   Record.push_back(N->isLocalToUnit());
1070   Record.push_back(N->isDefinition());
1071   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1072   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1073
1074   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1075   Record.clear();
1076 }
1077
1078 static void WriteMDLocalVariable(const MDLocalVariable *N,
1079                                  const ValueEnumerator &VE,
1080                                  BitstreamWriter &Stream,
1081                                  SmallVectorImpl<uint64_t> &Record,
1082                                  unsigned Abbrev) {
1083   Record.push_back(N->isDistinct());
1084   Record.push_back(N->getTag());
1085   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1086   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1087   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1088   Record.push_back(N->getLine());
1089   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1090   Record.push_back(N->getArg());
1091   Record.push_back(N->getFlags());
1092
1093   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1094   Record.clear();
1095 }
1096
1097 static void WriteMDExpression(const MDExpression *N, const ValueEnumerator &,
1098                               BitstreamWriter &Stream,
1099                               SmallVectorImpl<uint64_t> &Record,
1100                               unsigned Abbrev) {
1101   Record.reserve(N->getElements().size() + 1);
1102
1103   Record.push_back(N->isDistinct());
1104   Record.append(N->elements_begin(), N->elements_end());
1105
1106   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1107   Record.clear();
1108 }
1109
1110 static void WriteMDObjCProperty(const MDObjCProperty *N,
1111                                  const ValueEnumerator &VE,
1112                                  BitstreamWriter &Stream,
1113                                  SmallVectorImpl<uint64_t> &Record,
1114                                  unsigned Abbrev) {
1115   Record.push_back(N->isDistinct());
1116   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1117   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1118   Record.push_back(N->getLine());
1119   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1120   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1121   Record.push_back(N->getAttributes());
1122   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1123
1124   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1125   Record.clear();
1126 }
1127
1128 static void WriteMDImportedEntity(const MDImportedEntity *N,
1129                                   const ValueEnumerator &VE,
1130                                   BitstreamWriter &Stream,
1131                                   SmallVectorImpl<uint64_t> &Record,
1132                                   unsigned Abbrev) {
1133   Record.push_back(N->isDistinct());
1134   Record.push_back(N->getTag());
1135   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1136   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1137   Record.push_back(N->getLine());
1138   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1139
1140   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1141   Record.clear();
1142 }
1143
1144 static void WriteModuleMetadata(const Module *M,
1145                                 const ValueEnumerator &VE,
1146                                 BitstreamWriter &Stream) {
1147   const auto &MDs = VE.getMDs();
1148   if (MDs.empty() && M->named_metadata_empty())
1149     return;
1150
1151   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1152
1153   unsigned MDSAbbrev = 0;
1154   if (VE.hasMDString()) {
1155     // Abbrev for METADATA_STRING.
1156     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1157     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1159     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1160     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1161   }
1162
1163   // Initialize MDNode abbreviations.
1164 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1165 #include "llvm/IR/Metadata.def"
1166
1167   if (VE.hasMDLocation()) {
1168     // Abbrev for METADATA_LOCATION.
1169     //
1170     // Assume the column is usually under 128, and always output the inlined-at
1171     // location (it's never more expensive than building an array size 1).
1172     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1173     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1174     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1179     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
1180   }
1181
1182   if (VE.hasGenericDebugNode()) {
1183     // Abbrev for METADATA_GENERIC_DEBUG.
1184     //
1185     // Assume the column is usually under 128, and always output the inlined-at
1186     // location (it's never more expensive than building an array size 1).
1187     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1188     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1195     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1196   }
1197
1198   unsigned NameAbbrev = 0;
1199   if (!M->named_metadata_empty()) {
1200     // Abbrev for METADATA_NAME.
1201     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1202     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1203     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1205     NameAbbrev = Stream.EmitAbbrev(Abbv);
1206   }
1207
1208   SmallVector<uint64_t, 64> Record;
1209   for (const Metadata *MD : MDs) {
1210     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1211       assert(N->isResolved() && "Expected forward references to be resolved");
1212
1213       switch (N->getMetadataID()) {
1214       default:
1215         llvm_unreachable("Invalid MDNode subclass");
1216 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1217   case Metadata::CLASS##Kind:                                                  \
1218     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1219     continue;
1220 #include "llvm/IR/Metadata.def"
1221       }
1222     }
1223     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1224       WriteValueAsMetadata(MDC, VE, Stream, Record);
1225       continue;
1226     }
1227     const MDString *MDS = cast<MDString>(MD);
1228     // Code: [strchar x N]
1229     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1230
1231     // Emit the finished record.
1232     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1233     Record.clear();
1234   }
1235
1236   // Write named metadata.
1237   for (const NamedMDNode &NMD : M->named_metadata()) {
1238     // Write name.
1239     StringRef Str = NMD.getName();
1240     Record.append(Str.bytes_begin(), Str.bytes_end());
1241     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1242     Record.clear();
1243
1244     // Write named metadata operands.
1245     for (const MDNode *N : NMD.operands())
1246       Record.push_back(VE.getMetadataID(N));
1247     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1248     Record.clear();
1249   }
1250
1251   Stream.ExitBlock();
1252 }
1253
1254 static void WriteFunctionLocalMetadata(const Function &F,
1255                                        const ValueEnumerator &VE,
1256                                        BitstreamWriter &Stream) {
1257   bool StartedMetadataBlock = false;
1258   SmallVector<uint64_t, 64> Record;
1259   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1260       VE.getFunctionLocalMDs();
1261   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1262     assert(MDs[i] && "Expected valid function-local metadata");
1263     if (!StartedMetadataBlock) {
1264       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1265       StartedMetadataBlock = true;
1266     }
1267     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1268   }
1269
1270   if (StartedMetadataBlock)
1271     Stream.ExitBlock();
1272 }
1273
1274 static void WriteMetadataAttachment(const Function &F,
1275                                     const ValueEnumerator &VE,
1276                                     BitstreamWriter &Stream) {
1277   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1278
1279   SmallVector<uint64_t, 64> Record;
1280
1281   // Write metadata attachments
1282   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1283   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1284   F.getAllMetadata(MDs);
1285   if (!MDs.empty()) {
1286     for (const auto &I : MDs) {
1287       Record.push_back(I.first);
1288       Record.push_back(VE.getMetadataID(I.second));
1289     }
1290     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1291     Record.clear();
1292   }
1293
1294   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1295     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1296          I != E; ++I) {
1297       MDs.clear();
1298       I->getAllMetadataOtherThanDebugLoc(MDs);
1299
1300       // If no metadata, ignore instruction.
1301       if (MDs.empty()) continue;
1302
1303       Record.push_back(VE.getInstructionID(I));
1304
1305       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1306         Record.push_back(MDs[i].first);
1307         Record.push_back(VE.getMetadataID(MDs[i].second));
1308       }
1309       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1310       Record.clear();
1311     }
1312
1313   Stream.ExitBlock();
1314 }
1315
1316 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1317   SmallVector<uint64_t, 64> Record;
1318
1319   // Write metadata kinds
1320   // METADATA_KIND - [n x [id, name]]
1321   SmallVector<StringRef, 8> Names;
1322   M->getMDKindNames(Names);
1323
1324   if (Names.empty()) return;
1325
1326   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1327
1328   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1329     Record.push_back(MDKindID);
1330     StringRef KName = Names[MDKindID];
1331     Record.append(KName.begin(), KName.end());
1332
1333     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1334     Record.clear();
1335   }
1336
1337   Stream.ExitBlock();
1338 }
1339
1340 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1341   if ((int64_t)V >= 0)
1342     Vals.push_back(V << 1);
1343   else
1344     Vals.push_back((-V << 1) | 1);
1345 }
1346
1347 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1348                            const ValueEnumerator &VE,
1349                            BitstreamWriter &Stream, bool isGlobal) {
1350   if (FirstVal == LastVal) return;
1351
1352   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1353
1354   unsigned AggregateAbbrev = 0;
1355   unsigned String8Abbrev = 0;
1356   unsigned CString7Abbrev = 0;
1357   unsigned CString6Abbrev = 0;
1358   // If this is a constant pool for the module, emit module-specific abbrevs.
1359   if (isGlobal) {
1360     // Abbrev for CST_CODE_AGGREGATE.
1361     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1362     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1365     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1366
1367     // Abbrev for CST_CODE_STRING.
1368     Abbv = new BitCodeAbbrev();
1369     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1372     String8Abbrev = Stream.EmitAbbrev(Abbv);
1373     // Abbrev for CST_CODE_CSTRING.
1374     Abbv = new BitCodeAbbrev();
1375     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1378     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1379     // Abbrev for CST_CODE_CSTRING.
1380     Abbv = new BitCodeAbbrev();
1381     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1384     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1385   }
1386
1387   SmallVector<uint64_t, 64> Record;
1388
1389   const ValueEnumerator::ValueList &Vals = VE.getValues();
1390   Type *LastTy = nullptr;
1391   for (unsigned i = FirstVal; i != LastVal; ++i) {
1392     const Value *V = Vals[i].first;
1393     // If we need to switch types, do so now.
1394     if (V->getType() != LastTy) {
1395       LastTy = V->getType();
1396       Record.push_back(VE.getTypeID(LastTy));
1397       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1398                         CONSTANTS_SETTYPE_ABBREV);
1399       Record.clear();
1400     }
1401
1402     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1403       Record.push_back(unsigned(IA->hasSideEffects()) |
1404                        unsigned(IA->isAlignStack()) << 1 |
1405                        unsigned(IA->getDialect()&1) << 2);
1406
1407       // Add the asm string.
1408       const std::string &AsmStr = IA->getAsmString();
1409       Record.push_back(AsmStr.size());
1410       Record.append(AsmStr.begin(), AsmStr.end());
1411
1412       // Add the constraint string.
1413       const std::string &ConstraintStr = IA->getConstraintString();
1414       Record.push_back(ConstraintStr.size());
1415       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1416       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1417       Record.clear();
1418       continue;
1419     }
1420     const Constant *C = cast<Constant>(V);
1421     unsigned Code = -1U;
1422     unsigned AbbrevToUse = 0;
1423     if (C->isNullValue()) {
1424       Code = bitc::CST_CODE_NULL;
1425     } else if (isa<UndefValue>(C)) {
1426       Code = bitc::CST_CODE_UNDEF;
1427     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1428       if (IV->getBitWidth() <= 64) {
1429         uint64_t V = IV->getSExtValue();
1430         emitSignedInt64(Record, V);
1431         Code = bitc::CST_CODE_INTEGER;
1432         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1433       } else {                             // Wide integers, > 64 bits in size.
1434         // We have an arbitrary precision integer value to write whose
1435         // bit width is > 64. However, in canonical unsigned integer
1436         // format it is likely that the high bits are going to be zero.
1437         // So, we only write the number of active words.
1438         unsigned NWords = IV->getValue().getActiveWords();
1439         const uint64_t *RawWords = IV->getValue().getRawData();
1440         for (unsigned i = 0; i != NWords; ++i) {
1441           emitSignedInt64(Record, RawWords[i]);
1442         }
1443         Code = bitc::CST_CODE_WIDE_INTEGER;
1444       }
1445     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1446       Code = bitc::CST_CODE_FLOAT;
1447       Type *Ty = CFP->getType();
1448       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1449         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1450       } else if (Ty->isX86_FP80Ty()) {
1451         // api needed to prevent premature destruction
1452         // bits are not in the same order as a normal i80 APInt, compensate.
1453         APInt api = CFP->getValueAPF().bitcastToAPInt();
1454         const uint64_t *p = api.getRawData();
1455         Record.push_back((p[1] << 48) | (p[0] >> 16));
1456         Record.push_back(p[0] & 0xffffLL);
1457       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1458         APInt api = CFP->getValueAPF().bitcastToAPInt();
1459         const uint64_t *p = api.getRawData();
1460         Record.push_back(p[0]);
1461         Record.push_back(p[1]);
1462       } else {
1463         assert (0 && "Unknown FP type!");
1464       }
1465     } else if (isa<ConstantDataSequential>(C) &&
1466                cast<ConstantDataSequential>(C)->isString()) {
1467       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1468       // Emit constant strings specially.
1469       unsigned NumElts = Str->getNumElements();
1470       // If this is a null-terminated string, use the denser CSTRING encoding.
1471       if (Str->isCString()) {
1472         Code = bitc::CST_CODE_CSTRING;
1473         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1474       } else {
1475         Code = bitc::CST_CODE_STRING;
1476         AbbrevToUse = String8Abbrev;
1477       }
1478       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1479       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1480       for (unsigned i = 0; i != NumElts; ++i) {
1481         unsigned char V = Str->getElementAsInteger(i);
1482         Record.push_back(V);
1483         isCStr7 &= (V & 128) == 0;
1484         if (isCStrChar6)
1485           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1486       }
1487
1488       if (isCStrChar6)
1489         AbbrevToUse = CString6Abbrev;
1490       else if (isCStr7)
1491         AbbrevToUse = CString7Abbrev;
1492     } else if (const ConstantDataSequential *CDS =
1493                   dyn_cast<ConstantDataSequential>(C)) {
1494       Code = bitc::CST_CODE_DATA;
1495       Type *EltTy = CDS->getType()->getElementType();
1496       if (isa<IntegerType>(EltTy)) {
1497         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1498           Record.push_back(CDS->getElementAsInteger(i));
1499       } else if (EltTy->isFloatTy()) {
1500         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1501           union { float F; uint32_t I; };
1502           F = CDS->getElementAsFloat(i);
1503           Record.push_back(I);
1504         }
1505       } else {
1506         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1507         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1508           union { double F; uint64_t I; };
1509           F = CDS->getElementAsDouble(i);
1510           Record.push_back(I);
1511         }
1512       }
1513     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1514                isa<ConstantVector>(C)) {
1515       Code = bitc::CST_CODE_AGGREGATE;
1516       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1517         Record.push_back(VE.getValueID(C->getOperand(i)));
1518       AbbrevToUse = AggregateAbbrev;
1519     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1520       switch (CE->getOpcode()) {
1521       default:
1522         if (Instruction::isCast(CE->getOpcode())) {
1523           Code = bitc::CST_CODE_CE_CAST;
1524           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1525           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1526           Record.push_back(VE.getValueID(C->getOperand(0)));
1527           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1528         } else {
1529           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1530           Code = bitc::CST_CODE_CE_BINOP;
1531           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1532           Record.push_back(VE.getValueID(C->getOperand(0)));
1533           Record.push_back(VE.getValueID(C->getOperand(1)));
1534           uint64_t Flags = GetOptimizationFlags(CE);
1535           if (Flags != 0)
1536             Record.push_back(Flags);
1537         }
1538         break;
1539       case Instruction::GetElementPtr: {
1540         Code = bitc::CST_CODE_CE_GEP;
1541         const auto *GO = cast<GEPOperator>(C);
1542         if (GO->isInBounds())
1543           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1544         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1545         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1546           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1547           Record.push_back(VE.getValueID(C->getOperand(i)));
1548         }
1549         break;
1550       }
1551       case Instruction::Select:
1552         Code = bitc::CST_CODE_CE_SELECT;
1553         Record.push_back(VE.getValueID(C->getOperand(0)));
1554         Record.push_back(VE.getValueID(C->getOperand(1)));
1555         Record.push_back(VE.getValueID(C->getOperand(2)));
1556         break;
1557       case Instruction::ExtractElement:
1558         Code = bitc::CST_CODE_CE_EXTRACTELT;
1559         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1560         Record.push_back(VE.getValueID(C->getOperand(0)));
1561         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1562         Record.push_back(VE.getValueID(C->getOperand(1)));
1563         break;
1564       case Instruction::InsertElement:
1565         Code = bitc::CST_CODE_CE_INSERTELT;
1566         Record.push_back(VE.getValueID(C->getOperand(0)));
1567         Record.push_back(VE.getValueID(C->getOperand(1)));
1568         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1569         Record.push_back(VE.getValueID(C->getOperand(2)));
1570         break;
1571       case Instruction::ShuffleVector:
1572         // If the return type and argument types are the same, this is a
1573         // standard shufflevector instruction.  If the types are different,
1574         // then the shuffle is widening or truncating the input vectors, and
1575         // the argument type must also be encoded.
1576         if (C->getType() == C->getOperand(0)->getType()) {
1577           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1578         } else {
1579           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1580           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1581         }
1582         Record.push_back(VE.getValueID(C->getOperand(0)));
1583         Record.push_back(VE.getValueID(C->getOperand(1)));
1584         Record.push_back(VE.getValueID(C->getOperand(2)));
1585         break;
1586       case Instruction::ICmp:
1587       case Instruction::FCmp:
1588         Code = bitc::CST_CODE_CE_CMP;
1589         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1590         Record.push_back(VE.getValueID(C->getOperand(0)));
1591         Record.push_back(VE.getValueID(C->getOperand(1)));
1592         Record.push_back(CE->getPredicate());
1593         break;
1594       }
1595     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1596       Code = bitc::CST_CODE_BLOCKADDRESS;
1597       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1598       Record.push_back(VE.getValueID(BA->getFunction()));
1599       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1600     } else {
1601 #ifndef NDEBUG
1602       C->dump();
1603 #endif
1604       llvm_unreachable("Unknown constant!");
1605     }
1606     Stream.EmitRecord(Code, Record, AbbrevToUse);
1607     Record.clear();
1608   }
1609
1610   Stream.ExitBlock();
1611 }
1612
1613 static void WriteModuleConstants(const ValueEnumerator &VE,
1614                                  BitstreamWriter &Stream) {
1615   const ValueEnumerator::ValueList &Vals = VE.getValues();
1616
1617   // Find the first constant to emit, which is the first non-globalvalue value.
1618   // We know globalvalues have been emitted by WriteModuleInfo.
1619   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1620     if (!isa<GlobalValue>(Vals[i].first)) {
1621       WriteConstants(i, Vals.size(), VE, Stream, true);
1622       return;
1623     }
1624   }
1625 }
1626
1627 /// PushValueAndType - The file has to encode both the value and type id for
1628 /// many values, because we need to know what type to create for forward
1629 /// references.  However, most operands are not forward references, so this type
1630 /// field is not needed.
1631 ///
1632 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1633 /// instruction ID, then it is a forward reference, and it also includes the
1634 /// type ID.  The value ID that is written is encoded relative to the InstID.
1635 static bool PushValueAndType(const Value *V, unsigned InstID,
1636                              SmallVectorImpl<unsigned> &Vals,
1637                              ValueEnumerator &VE) {
1638   unsigned ValID = VE.getValueID(V);
1639   // Make encoding relative to the InstID.
1640   Vals.push_back(InstID - ValID);
1641   if (ValID >= InstID) {
1642     Vals.push_back(VE.getTypeID(V->getType()));
1643     return true;
1644   }
1645   return false;
1646 }
1647
1648 /// pushValue - Like PushValueAndType, but where the type of the value is
1649 /// omitted (perhaps it was already encoded in an earlier operand).
1650 static void pushValue(const Value *V, unsigned InstID,
1651                       SmallVectorImpl<unsigned> &Vals,
1652                       ValueEnumerator &VE) {
1653   unsigned ValID = VE.getValueID(V);
1654   Vals.push_back(InstID - ValID);
1655 }
1656
1657 static void pushValueSigned(const Value *V, unsigned InstID,
1658                             SmallVectorImpl<uint64_t> &Vals,
1659                             ValueEnumerator &VE) {
1660   unsigned ValID = VE.getValueID(V);
1661   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1662   emitSignedInt64(Vals, diff);
1663 }
1664
1665 /// WriteInstruction - Emit an instruction to the specified stream.
1666 static void WriteInstruction(const Instruction &I, unsigned InstID,
1667                              ValueEnumerator &VE, BitstreamWriter &Stream,
1668                              SmallVectorImpl<unsigned> &Vals) {
1669   unsigned Code = 0;
1670   unsigned AbbrevToUse = 0;
1671   VE.setInstructionID(&I);
1672   switch (I.getOpcode()) {
1673   default:
1674     if (Instruction::isCast(I.getOpcode())) {
1675       Code = bitc::FUNC_CODE_INST_CAST;
1676       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1677         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1678       Vals.push_back(VE.getTypeID(I.getType()));
1679       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1680     } else {
1681       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1682       Code = bitc::FUNC_CODE_INST_BINOP;
1683       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1684         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1685       pushValue(I.getOperand(1), InstID, Vals, VE);
1686       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1687       uint64_t Flags = GetOptimizationFlags(&I);
1688       if (Flags != 0) {
1689         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1690           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1691         Vals.push_back(Flags);
1692       }
1693     }
1694     break;
1695
1696   case Instruction::GetElementPtr: {
1697     Code = bitc::FUNC_CODE_INST_GEP;
1698     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1699     auto &GEPInst = cast<GetElementPtrInst>(I);
1700     Vals.push_back(GEPInst.isInBounds());
1701     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1702     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1703       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1704     break;
1705   }
1706   case Instruction::ExtractValue: {
1707     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1708     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1709     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1710     Vals.append(EVI->idx_begin(), EVI->idx_end());
1711     break;
1712   }
1713   case Instruction::InsertValue: {
1714     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1715     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1716     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1717     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1718     Vals.append(IVI->idx_begin(), IVI->idx_end());
1719     break;
1720   }
1721   case Instruction::Select:
1722     Code = bitc::FUNC_CODE_INST_VSELECT;
1723     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1724     pushValue(I.getOperand(2), InstID, Vals, VE);
1725     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1726     break;
1727   case Instruction::ExtractElement:
1728     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1729     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1730     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1731     break;
1732   case Instruction::InsertElement:
1733     Code = bitc::FUNC_CODE_INST_INSERTELT;
1734     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1735     pushValue(I.getOperand(1), InstID, Vals, VE);
1736     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1737     break;
1738   case Instruction::ShuffleVector:
1739     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1740     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1741     pushValue(I.getOperand(1), InstID, Vals, VE);
1742     pushValue(I.getOperand(2), InstID, Vals, VE);
1743     break;
1744   case Instruction::ICmp:
1745   case Instruction::FCmp:
1746     // compare returning Int1Ty or vector of Int1Ty
1747     Code = bitc::FUNC_CODE_INST_CMP2;
1748     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1749     pushValue(I.getOperand(1), InstID, Vals, VE);
1750     Vals.push_back(cast<CmpInst>(I).getPredicate());
1751     break;
1752
1753   case Instruction::Ret:
1754     {
1755       Code = bitc::FUNC_CODE_INST_RET;
1756       unsigned NumOperands = I.getNumOperands();
1757       if (NumOperands == 0)
1758         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1759       else if (NumOperands == 1) {
1760         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1761           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1762       } else {
1763         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1764           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1765       }
1766     }
1767     break;
1768   case Instruction::Br:
1769     {
1770       Code = bitc::FUNC_CODE_INST_BR;
1771       const BranchInst &II = cast<BranchInst>(I);
1772       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1773       if (II.isConditional()) {
1774         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1775         pushValue(II.getCondition(), InstID, Vals, VE);
1776       }
1777     }
1778     break;
1779   case Instruction::Switch:
1780     {
1781       Code = bitc::FUNC_CODE_INST_SWITCH;
1782       const SwitchInst &SI = cast<SwitchInst>(I);
1783       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1784       pushValue(SI.getCondition(), InstID, Vals, VE);
1785       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1786       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1787            i != e; ++i) {
1788         Vals.push_back(VE.getValueID(i.getCaseValue()));
1789         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1790       }
1791     }
1792     break;
1793   case Instruction::IndirectBr:
1794     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1795     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1796     // Encode the address operand as relative, but not the basic blocks.
1797     pushValue(I.getOperand(0), InstID, Vals, VE);
1798     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1799       Vals.push_back(VE.getValueID(I.getOperand(i)));
1800     break;
1801
1802   case Instruction::Invoke: {
1803     const InvokeInst *II = cast<InvokeInst>(&I);
1804     const Value *Callee = II->getCalledValue();
1805     FunctionType *FTy = II->getFunctionType();
1806     Code = bitc::FUNC_CODE_INST_INVOKE;
1807
1808     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1809     Vals.push_back(II->getCallingConv() | 1 << 13);
1810     Vals.push_back(VE.getValueID(II->getNormalDest()));
1811     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1812     Vals.push_back(VE.getTypeID(FTy));
1813     PushValueAndType(Callee, InstID, Vals, VE);
1814
1815     // Emit value #'s for the fixed parameters.
1816     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1817       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1818
1819     // Emit type/value pairs for varargs params.
1820     if (FTy->isVarArg()) {
1821       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1822            i != e; ++i)
1823         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1824     }
1825     break;
1826   }
1827   case Instruction::Resume:
1828     Code = bitc::FUNC_CODE_INST_RESUME;
1829     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1830     break;
1831   case Instruction::Unreachable:
1832     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1833     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1834     break;
1835
1836   case Instruction::PHI: {
1837     const PHINode &PN = cast<PHINode>(I);
1838     Code = bitc::FUNC_CODE_INST_PHI;
1839     // With the newer instruction encoding, forward references could give
1840     // negative valued IDs.  This is most common for PHIs, so we use
1841     // signed VBRs.
1842     SmallVector<uint64_t, 128> Vals64;
1843     Vals64.push_back(VE.getTypeID(PN.getType()));
1844     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1845       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1846       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1847     }
1848     // Emit a Vals64 vector and exit.
1849     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1850     Vals64.clear();
1851     return;
1852   }
1853
1854   case Instruction::LandingPad: {
1855     const LandingPadInst &LP = cast<LandingPadInst>(I);
1856     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1857     Vals.push_back(VE.getTypeID(LP.getType()));
1858     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1859     Vals.push_back(LP.isCleanup());
1860     Vals.push_back(LP.getNumClauses());
1861     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1862       if (LP.isCatch(I))
1863         Vals.push_back(LandingPadInst::Catch);
1864       else
1865         Vals.push_back(LandingPadInst::Filter);
1866       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1867     }
1868     break;
1869   }
1870
1871   case Instruction::Alloca: {
1872     Code = bitc::FUNC_CODE_INST_ALLOCA;
1873     Vals.push_back(VE.getTypeID(I.getType()));
1874     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1875     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1876     const AllocaInst &AI = cast<AllocaInst>(I);
1877     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1878     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1879            "not enough bits for maximum alignment");
1880     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1881     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1882     Vals.push_back(AlignRecord);
1883     break;
1884   }
1885
1886   case Instruction::Load:
1887     if (cast<LoadInst>(I).isAtomic()) {
1888       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1889       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1890     } else {
1891       Code = bitc::FUNC_CODE_INST_LOAD;
1892       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1893         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1894     }
1895     Vals.push_back(VE.getTypeID(I.getType()));
1896     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1897     Vals.push_back(cast<LoadInst>(I).isVolatile());
1898     if (cast<LoadInst>(I).isAtomic()) {
1899       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1900       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1901     }
1902     break;
1903   case Instruction::Store:
1904     if (cast<StoreInst>(I).isAtomic())
1905       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1906     else
1907       Code = bitc::FUNC_CODE_INST_STORE;
1908     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1909     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
1910     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1911     Vals.push_back(cast<StoreInst>(I).isVolatile());
1912     if (cast<StoreInst>(I).isAtomic()) {
1913       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1914       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1915     }
1916     break;
1917   case Instruction::AtomicCmpXchg:
1918     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1919     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1920     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
1921     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1922     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1923     Vals.push_back(GetEncodedOrdering(
1924                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1925     Vals.push_back(GetEncodedSynchScope(
1926                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1927     Vals.push_back(GetEncodedOrdering(
1928                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1929     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1930     break;
1931   case Instruction::AtomicRMW:
1932     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1933     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1934     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1935     Vals.push_back(GetEncodedRMWOperation(
1936                      cast<AtomicRMWInst>(I).getOperation()));
1937     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1938     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1939     Vals.push_back(GetEncodedSynchScope(
1940                      cast<AtomicRMWInst>(I).getSynchScope()));
1941     break;
1942   case Instruction::Fence:
1943     Code = bitc::FUNC_CODE_INST_FENCE;
1944     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1945     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1946     break;
1947   case Instruction::Call: {
1948     const CallInst &CI = cast<CallInst>(I);
1949     FunctionType *FTy = CI.getFunctionType();
1950
1951     Code = bitc::FUNC_CODE_INST_CALL;
1952
1953     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1954     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1955                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
1956     Vals.push_back(VE.getTypeID(FTy));
1957     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1958
1959     // Emit value #'s for the fixed parameters.
1960     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1961       // Check for labels (can happen with asm labels).
1962       if (FTy->getParamType(i)->isLabelTy())
1963         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1964       else
1965         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1966     }
1967
1968     // Emit type/value pairs for varargs params.
1969     if (FTy->isVarArg()) {
1970       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1971            i != e; ++i)
1972         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1973     }
1974     break;
1975   }
1976   case Instruction::VAArg:
1977     Code = bitc::FUNC_CODE_INST_VAARG;
1978     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1979     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1980     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1981     break;
1982   }
1983
1984   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1985   Vals.clear();
1986 }
1987
1988 // Emit names for globals/functions etc.
1989 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1990                                   const ValueEnumerator &VE,
1991                                   BitstreamWriter &Stream) {
1992   if (VST.empty()) return;
1993   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1994
1995   // FIXME: Set up the abbrev, we know how many values there are!
1996   // FIXME: We know if the type names can use 7-bit ascii.
1997   SmallVector<unsigned, 64> NameVals;
1998
1999   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
2000        SI != SE; ++SI) {
2001
2002     const ValueName &Name = *SI;
2003
2004     // Figure out the encoding to use for the name.
2005     bool is7Bit = true;
2006     bool isChar6 = true;
2007     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
2008          C != E; ++C) {
2009       if (isChar6)
2010         isChar6 = BitCodeAbbrevOp::isChar6(*C);
2011       if ((unsigned char)*C & 128) {
2012         is7Bit = false;
2013         break;  // don't bother scanning the rest.
2014       }
2015     }
2016
2017     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2018
2019     // VST_ENTRY:   [valueid, namechar x N]
2020     // VST_BBENTRY: [bbid, namechar x N]
2021     unsigned Code;
2022     if (isa<BasicBlock>(SI->getValue())) {
2023       Code = bitc::VST_CODE_BBENTRY;
2024       if (isChar6)
2025         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2026     } else {
2027       Code = bitc::VST_CODE_ENTRY;
2028       if (isChar6)
2029         AbbrevToUse = VST_ENTRY_6_ABBREV;
2030       else if (is7Bit)
2031         AbbrevToUse = VST_ENTRY_7_ABBREV;
2032     }
2033
2034     NameVals.push_back(VE.getValueID(SI->getValue()));
2035     for (const char *P = Name.getKeyData(),
2036          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2037       NameVals.push_back((unsigned char)*P);
2038
2039     // Emit the finished record.
2040     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2041     NameVals.clear();
2042   }
2043   Stream.ExitBlock();
2044 }
2045
2046 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2047                          BitstreamWriter &Stream) {
2048   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2049   unsigned Code;
2050   if (isa<BasicBlock>(Order.V))
2051     Code = bitc::USELIST_CODE_BB;
2052   else
2053     Code = bitc::USELIST_CODE_DEFAULT;
2054
2055   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2056   Record.push_back(VE.getValueID(Order.V));
2057   Stream.EmitRecord(Code, Record);
2058 }
2059
2060 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2061                               BitstreamWriter &Stream) {
2062   assert(VE.shouldPreserveUseListOrder() &&
2063          "Expected to be preserving use-list order");
2064
2065   auto hasMore = [&]() {
2066     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2067   };
2068   if (!hasMore())
2069     // Nothing to do.
2070     return;
2071
2072   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2073   while (hasMore()) {
2074     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2075     VE.UseListOrders.pop_back();
2076   }
2077   Stream.ExitBlock();
2078 }
2079
2080 /// WriteFunction - Emit a function body to the module stream.
2081 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2082                           BitstreamWriter &Stream) {
2083   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2084   VE.incorporateFunction(F);
2085
2086   SmallVector<unsigned, 64> Vals;
2087
2088   // Emit the number of basic blocks, so the reader can create them ahead of
2089   // time.
2090   Vals.push_back(VE.getBasicBlocks().size());
2091   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2092   Vals.clear();
2093
2094   // If there are function-local constants, emit them now.
2095   unsigned CstStart, CstEnd;
2096   VE.getFunctionConstantRange(CstStart, CstEnd);
2097   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2098
2099   // If there is function-local metadata, emit it now.
2100   WriteFunctionLocalMetadata(F, VE, Stream);
2101
2102   // Keep a running idea of what the instruction ID is.
2103   unsigned InstID = CstEnd;
2104
2105   bool NeedsMetadataAttachment = F.hasMetadata();
2106
2107   MDLocation *LastDL = nullptr;
2108
2109   // Finally, emit all the instructions, in order.
2110   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2111     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2112          I != E; ++I) {
2113       WriteInstruction(*I, InstID, VE, Stream, Vals);
2114
2115       if (!I->getType()->isVoidTy())
2116         ++InstID;
2117
2118       // If the instruction has metadata, write a metadata attachment later.
2119       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2120
2121       // If the instruction has a debug location, emit it.
2122       MDLocation *DL = I->getDebugLoc();
2123       if (!DL)
2124         continue;
2125
2126       if (DL == LastDL) {
2127         // Just repeat the same debug loc as last time.
2128         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2129         continue;
2130       }
2131
2132       Vals.push_back(DL->getLine());
2133       Vals.push_back(DL->getColumn());
2134       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2135       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2136       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2137       Vals.clear();
2138     }
2139
2140   // Emit names for all the instructions etc.
2141   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2142
2143   if (NeedsMetadataAttachment)
2144     WriteMetadataAttachment(F, VE, Stream);
2145   if (VE.shouldPreserveUseListOrder())
2146     WriteUseListBlock(&F, VE, Stream);
2147   VE.purgeFunction();
2148   Stream.ExitBlock();
2149 }
2150
2151 // Emit blockinfo, which defines the standard abbreviations etc.
2152 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2153   // We only want to emit block info records for blocks that have multiple
2154   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2155   // Other blocks can define their abbrevs inline.
2156   Stream.EnterBlockInfoBlock(2);
2157
2158   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2159     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2161     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2162     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2164     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2165                                    Abbv) != VST_ENTRY_8_ABBREV)
2166       llvm_unreachable("Unexpected abbrev ordering!");
2167   }
2168
2169   { // 7-bit fixed width VST_ENTRY strings.
2170     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2171     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2172     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2174     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2175     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2176                                    Abbv) != VST_ENTRY_7_ABBREV)
2177       llvm_unreachable("Unexpected abbrev ordering!");
2178   }
2179   { // 6-bit char6 VST_ENTRY strings.
2180     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2181     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2184     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2185     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2186                                    Abbv) != VST_ENTRY_6_ABBREV)
2187       llvm_unreachable("Unexpected abbrev ordering!");
2188   }
2189   { // 6-bit char6 VST_BBENTRY strings.
2190     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2191     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2195     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2196                                    Abbv) != VST_BBENTRY_6_ABBREV)
2197       llvm_unreachable("Unexpected abbrev ordering!");
2198   }
2199
2200
2201
2202   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2203     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2204     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2206                               VE.computeBitsRequiredForTypeIndicies()));
2207     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2208                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2209       llvm_unreachable("Unexpected abbrev ordering!");
2210   }
2211
2212   { // INTEGER abbrev for CONSTANTS_BLOCK.
2213     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2214     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2216     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2217                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2218       llvm_unreachable("Unexpected abbrev ordering!");
2219   }
2220
2221   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2222     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2223     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2226                               VE.computeBitsRequiredForTypeIndicies()));
2227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2228
2229     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2230                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2231       llvm_unreachable("Unexpected abbrev ordering!");
2232   }
2233   { // NULL abbrev for CONSTANTS_BLOCK.
2234     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2235     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2236     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2237                                    Abbv) != CONSTANTS_NULL_Abbrev)
2238       llvm_unreachable("Unexpected abbrev ordering!");
2239   }
2240
2241   // FIXME: This should only use space for first class types!
2242
2243   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2244     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2245     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2248                               VE.computeBitsRequiredForTypeIndicies()));
2249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2251     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2252                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2253       llvm_unreachable("Unexpected abbrev ordering!");
2254   }
2255   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2256     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2257     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2261     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2262                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2263       llvm_unreachable("Unexpected abbrev ordering!");
2264   }
2265   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2266     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2267     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2272     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2273                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2274       llvm_unreachable("Unexpected abbrev ordering!");
2275   }
2276   { // INST_CAST abbrev for FUNCTION_BLOCK.
2277     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2278     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2281                               VE.computeBitsRequiredForTypeIndicies()));
2282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2283     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2284                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2285       llvm_unreachable("Unexpected abbrev ordering!");
2286   }
2287
2288   { // INST_RET abbrev for FUNCTION_BLOCK.
2289     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2290     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2291     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2292                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2293       llvm_unreachable("Unexpected abbrev ordering!");
2294   }
2295   { // INST_RET abbrev for FUNCTION_BLOCK.
2296     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2297     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2299     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2300                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2301       llvm_unreachable("Unexpected abbrev ordering!");
2302   }
2303   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2304     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2305     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2306     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2307                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2308       llvm_unreachable("Unexpected abbrev ordering!");
2309   }
2310   {
2311     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2312     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2313     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2314     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2315                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2318     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2319         FUNCTION_INST_GEP_ABBREV)
2320       llvm_unreachable("Unexpected abbrev ordering!");
2321   }
2322
2323   Stream.ExitBlock();
2324 }
2325
2326 /// WriteModule - Emit the specified module to the bitstream.
2327 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2328                         bool ShouldPreserveUseListOrder) {
2329   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2330
2331   SmallVector<unsigned, 1> Vals;
2332   unsigned CurVersion = 1;
2333   Vals.push_back(CurVersion);
2334   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2335
2336   // Analyze the module, enumerating globals, functions, etc.
2337   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2338
2339   // Emit blockinfo, which defines the standard abbreviations etc.
2340   WriteBlockInfo(VE, Stream);
2341
2342   // Emit information about attribute groups.
2343   WriteAttributeGroupTable(VE, Stream);
2344
2345   // Emit information about parameter attributes.
2346   WriteAttributeTable(VE, Stream);
2347
2348   // Emit information describing all of the types in the module.
2349   WriteTypeTable(VE, Stream);
2350
2351   writeComdats(VE, Stream);
2352
2353   // Emit top-level description of module, including target triple, inline asm,
2354   // descriptors for global variables, and function prototype info.
2355   WriteModuleInfo(M, VE, Stream);
2356
2357   // Emit constants.
2358   WriteModuleConstants(VE, Stream);
2359
2360   // Emit metadata.
2361   WriteModuleMetadata(M, VE, Stream);
2362
2363   // Emit metadata.
2364   WriteModuleMetadataStore(M, Stream);
2365
2366   // Emit names for globals/functions etc.
2367   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2368
2369   // Emit module-level use-lists.
2370   if (VE.shouldPreserveUseListOrder())
2371     WriteUseListBlock(nullptr, VE, Stream);
2372
2373   // Emit function bodies.
2374   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2375     if (!F->isDeclaration())
2376       WriteFunction(*F, VE, Stream);
2377
2378   Stream.ExitBlock();
2379 }
2380
2381 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2382 /// header and trailer to make it compatible with the system archiver.  To do
2383 /// this we emit the following header, and then emit a trailer that pads the
2384 /// file out to be a multiple of 16 bytes.
2385 ///
2386 /// struct bc_header {
2387 ///   uint32_t Magic;         // 0x0B17C0DE
2388 ///   uint32_t Version;       // Version, currently always 0.
2389 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2390 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2391 ///   uint32_t CPUType;       // CPU specifier.
2392 ///   ... potentially more later ...
2393 /// };
2394 enum {
2395   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2396   DarwinBCHeaderSize = 5*4
2397 };
2398
2399 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2400                                uint32_t &Position) {
2401   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2402   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2403   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2404   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2405   Position += 4;
2406 }
2407
2408 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2409                                          const Triple &TT) {
2410   unsigned CPUType = ~0U;
2411
2412   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2413   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2414   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2415   // specific constants here because they are implicitly part of the Darwin ABI.
2416   enum {
2417     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2418     DARWIN_CPU_TYPE_X86        = 7,
2419     DARWIN_CPU_TYPE_ARM        = 12,
2420     DARWIN_CPU_TYPE_POWERPC    = 18
2421   };
2422
2423   Triple::ArchType Arch = TT.getArch();
2424   if (Arch == Triple::x86_64)
2425     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2426   else if (Arch == Triple::x86)
2427     CPUType = DARWIN_CPU_TYPE_X86;
2428   else if (Arch == Triple::ppc)
2429     CPUType = DARWIN_CPU_TYPE_POWERPC;
2430   else if (Arch == Triple::ppc64)
2431     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2432   else if (Arch == Triple::arm || Arch == Triple::thumb)
2433     CPUType = DARWIN_CPU_TYPE_ARM;
2434
2435   // Traditional Bitcode starts after header.
2436   assert(Buffer.size() >= DarwinBCHeaderSize &&
2437          "Expected header size to be reserved");
2438   unsigned BCOffset = DarwinBCHeaderSize;
2439   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2440
2441   // Write the magic and version.
2442   unsigned Position = 0;
2443   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2444   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2445   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2446   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2447   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2448
2449   // If the file is not a multiple of 16 bytes, insert dummy padding.
2450   while (Buffer.size() & 15)
2451     Buffer.push_back(0);
2452 }
2453
2454 /// WriteBitcodeToFile - Write the specified module to the specified output
2455 /// stream.
2456 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2457                               bool ShouldPreserveUseListOrder) {
2458   SmallVector<char, 0> Buffer;
2459   Buffer.reserve(256*1024);
2460
2461   // If this is darwin or another generic macho target, reserve space for the
2462   // header.
2463   Triple TT(M->getTargetTriple());
2464   if (TT.isOSDarwin())
2465     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2466
2467   // Emit the module into the buffer.
2468   {
2469     BitstreamWriter Stream(Buffer);
2470
2471     // Emit the file header.
2472     Stream.Emit((unsigned)'B', 8);
2473     Stream.Emit((unsigned)'C', 8);
2474     Stream.Emit(0x0, 4);
2475     Stream.Emit(0xC, 4);
2476     Stream.Emit(0xE, 4);
2477     Stream.Emit(0xD, 4);
2478
2479     // Emit the module.
2480     WriteModule(M, Stream, ShouldPreserveUseListOrder);
2481   }
2482
2483   if (TT.isOSDarwin())
2484     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2485
2486   // Write the generated bitstream to "Out".
2487   Out.write((char*)&Buffer.front(), Buffer.size());
2488 }