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/STLExtras.h"
  17 #include "llvm/ADT/Triple.h"
  18 #include "llvm/Bitcode/BitstreamWriter.h"
  19 #include "llvm/Bitcode/LLVMBitCodes.h"
  20 #include "llvm/IR/CallSite.h"
  21 #include "llvm/IR/Constants.h"
  22 #include "llvm/IR/DebugInfoMetadata.h"
  23 #include "llvm/IR/DerivedTypes.h"
  24 #include "llvm/IR/InlineAsm.h"
  25 #include "llvm/IR/Instructions.h"
  26 #include "llvm/IR/LLVMContext.h"
  27 #include "llvm/IR/IntrinsicInst.h"
  28 #include "llvm/IR/Module.h"
  29 #include "llvm/IR/Operator.h"
  30 #include "llvm/IR/UseListOrder.h"
  31 #include "llvm/IR/ValueSymbolTable.h"
  32 #include "llvm/Support/CommandLine.h"
  33 #include "llvm/Support/ErrorHandling.h"
  34 #include "llvm/Support/MathExtras.h"
  35 #include "llvm/Support/Program.h"
  36 #include "llvm/Support/raw_ostream.h"
  37 #include <cctype>
  38 #include <map>
  39 using namespace llvm;
  40
  41 /// These are manifest constants used by the bitcode writer. They do not need to
  42 /// be kept in sync with the reader, but need to be consistent within this file.
  43 enum {
  44   // VALUE_SYMTAB_BLOCK abbrev id's.
  45   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  46   VST_ENTRY_7_ABBREV,
  47   VST_ENTRY_6_ABBREV,
  48   VST_BBENTRY_6_ABBREV,
  49
  50   // CONSTANTS_BLOCK abbrev id's.
  51   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  52   CONSTANTS_INTEGER_ABBREV,
  53   CONSTANTS_CE_CAST_Abbrev,
  54   CONSTANTS_NULL_Abbrev,
  55
  56   // FUNCTION_BLOCK abbrev id's.
  57   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  58   FUNCTION_INST_BINOP_ABBREV,
  59   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  60   FUNCTION_INST_CAST_ABBREV,
  61   FUNCTION_INST_RET_VOID_ABBREV,
  62   FUNCTION_INST_RET_VAL_ABBREV,
  63   FUNCTION_INST_UNREACHABLE_ABBREV,
  64   FUNCTION_INST_GEP_ABBREV,
  65 };
  66
  67 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  68   switch (Opcode) {
  69   default: llvm_unreachable("Unknown cast instruction!");
  70   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  71   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  72   case Instruction::SExt    : return bitc::CAST_SEXT;
  73   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  74   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  75   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  76   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  77   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  78   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  79   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  80   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  81   case Instruction::BitCast : return bitc::CAST_BITCAST;
  82   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  83   }
  84 }
  85
  86 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  87   switch (Opcode) {
  88   default: llvm_unreachable("Unknown binary instruction!");
  89   case Instruction::Add:
  90   case Instruction::FAdd: return bitc::BINOP_ADD;
  91   case Instruction::Sub:
  92   case Instruction::FSub: return bitc::BINOP_SUB;
  93   case Instruction::Mul:
  94   case Instruction::FMul: return bitc::BINOP_MUL;
  95   case Instruction::UDiv: return bitc::BINOP_UDIV;
  96   case Instruction::FDiv:
  97   case Instruction::SDiv: return bitc::BINOP_SDIV;
  98   case Instruction::URem: return bitc::BINOP_UREM;
  99   case Instruction::FRem:
 100   case Instruction::SRem: return bitc::BINOP_SREM;
 101   case Instruction::Shl:  return bitc::BINOP_SHL;
 102   case Instruction::LShr: return bitc::BINOP_LSHR;
 103   case Instruction::AShr: return bitc::BINOP_ASHR;
 104   case Instruction::And:  return bitc::BINOP_AND;
 105   case Instruction::Or:   return bitc::BINOP_OR;
 106   case Instruction::Xor:  return bitc::BINOP_XOR;
 107   }
 108 }
 109
 110 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 111   switch (Op) {
 112   default: llvm_unreachable("Unknown RMW operation!");
 113   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 114   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 115   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 116   case AtomicRMWInst::And: return bitc::RMW_AND;
 117   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 118   case AtomicRMWInst::Or: return bitc::RMW_OR;
 119   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 120   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 121   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 122   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 123   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 124   }
 125 }
 126
 127 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 128   switch (Ordering) {
 129   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 130   case Unordered: return bitc::ORDERING_UNORDERED;
 131   case Monotonic: return bitc::ORDERING_MONOTONIC;
 132   case Acquire: return bitc::ORDERING_ACQUIRE;
 133   case Release: return bitc::ORDERING_RELEASE;
 134   case AcquireRelease: return bitc::ORDERING_ACQREL;
 135   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 136   }
 137   llvm_unreachable("Invalid ordering");
 138 }
 139
 140 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 141   switch (SynchScope) {
 142   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 143   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 144   }
 145   llvm_unreachable("Invalid synch scope");
 146 }
 147
 148 static void WriteStringRecord(unsigned Code, StringRef Str,
 149                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 150   SmallVector<unsigned, 64> Vals;
 151
 152   // Code: [strchar x N]
 153   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 154     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 155       AbbrevToUse = 0;
 156     Vals.push_back(Str[i]);
 157   }
 158
 159   // Emit the finished record.
 160   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 161 }
 162
 163 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 164   switch (Kind) {
 165   case Attribute::Alignment:
 166     return bitc::ATTR_KIND_ALIGNMENT;
 167   case Attribute::AlwaysInline:
 168     return bitc::ATTR_KIND_ALWAYS_INLINE;
 169   case Attribute::ArgMemOnly:
 170     return bitc::ATTR_KIND_ARGMEMONLY;
 171   case Attribute::Builtin:
 172     return bitc::ATTR_KIND_BUILTIN;
 173   case Attribute::ByVal:
 174     return bitc::ATTR_KIND_BY_VAL;
 175   case Attribute::Convergent:
 176     return bitc::ATTR_KIND_CONVERGENT;
 177   case Attribute::InAlloca:
 178     return bitc::ATTR_KIND_IN_ALLOCA;
 179   case Attribute::Cold:
 180     return bitc::ATTR_KIND_COLD;
 181   case Attribute::InlineHint:
 182     return bitc::ATTR_KIND_INLINE_HINT;
 183   case Attribute::InReg:
 184     return bitc::ATTR_KIND_IN_REG;
 185   case Attribute::JumpTable:
 186     return bitc::ATTR_KIND_JUMP_TABLE;
 187   case Attribute::MinSize:
 188     return bitc::ATTR_KIND_MIN_SIZE;
 189   case Attribute::Naked:
 190     return bitc::ATTR_KIND_NAKED;
 191   case Attribute::Nest:
 192     return bitc::ATTR_KIND_NEST;
 193   case Attribute::NoAlias:
 194     return bitc::ATTR_KIND_NO_ALIAS;
 195   case Attribute::NoBuiltin:
 196     return bitc::ATTR_KIND_NO_BUILTIN;
 197   case Attribute::NoCapture:
 198     return bitc::ATTR_KIND_NO_CAPTURE;
 199   case Attribute::NoDuplicate:
 200     return bitc::ATTR_KIND_NO_DUPLICATE;
 201   case Attribute::NoImplicitFloat:
 202     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 203   case Attribute::NoInline:
 204     return bitc::ATTR_KIND_NO_INLINE;
 205   case Attribute::NoRecurse:
 206     return bitc::ATTR_KIND_NO_RECURSE;
 207   case Attribute::NonLazyBind:
 208     return bitc::ATTR_KIND_NON_LAZY_BIND;
 209   case Attribute::NonNull:
 210     return bitc::ATTR_KIND_NON_NULL;
 211   case Attribute::Dereferenceable:
 212     return bitc::ATTR_KIND_DEREFERENCEABLE;
 213   case Attribute::DereferenceableOrNull:
 214     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 215   case Attribute::NoRedZone:
 216     return bitc::ATTR_KIND_NO_RED_ZONE;
 217   case Attribute::NoReturn:
 218     return bitc::ATTR_KIND_NO_RETURN;
 219   case Attribute::NoUnwind:
 220     return bitc::ATTR_KIND_NO_UNWIND;
 221   case Attribute::OptimizeForSize:
 222     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 223   case Attribute::OptimizeNone:
 224     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 225   case Attribute::ReadNone:
 226     return bitc::ATTR_KIND_READ_NONE;
 227   case Attribute::ReadOnly:
 228     return bitc::ATTR_KIND_READ_ONLY;
 229   case Attribute::Returned:
 230     return bitc::ATTR_KIND_RETURNED;
 231   case Attribute::ReturnsTwice:
 232     return bitc::ATTR_KIND_RETURNS_TWICE;
 233   case Attribute::SExt:
 234     return bitc::ATTR_KIND_S_EXT;
 235   case Attribute::StackAlignment:
 236     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 237   case Attribute::StackProtect:
 238     return bitc::ATTR_KIND_STACK_PROTECT;
 239   case Attribute::StackProtectReq:
 240     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 241   case Attribute::StackProtectStrong:
 242     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 243   case Attribute::SafeStack:
 244     return bitc::ATTR_KIND_SAFESTACK;
 245   case Attribute::StructRet:
 246     return bitc::ATTR_KIND_STRUCT_RET;
 247   case Attribute::SanitizeAddress:
 248     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 249   case Attribute::SanitizeThread:
 250     return bitc::ATTR_KIND_SANITIZE_THREAD;
 251   case Attribute::SanitizeMemory:
 252     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 253   case Attribute::UWTable:
 254     return bitc::ATTR_KIND_UW_TABLE;
 255   case Attribute::ZExt:
 256     return bitc::ATTR_KIND_Z_EXT;
 257   case Attribute::EndAttrKinds:
 258     llvm_unreachable("Can not encode end-attribute kinds marker.");
 259   case Attribute::None:
 260     llvm_unreachable("Can not encode none-attribute.");
 261   }
 262
 263   llvm_unreachable("Trying to encode unknown attribute");
 264 }
 265
 266 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 267                                      BitstreamWriter &Stream) {
 268   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 269   if (AttrGrps.empty()) return;
 270
 271   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 272
 273   SmallVector<uint64_t, 64> Record;
 274   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 275     AttributeSet AS = AttrGrps[i];
 276     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 277       AttributeSet A = AS.getSlotAttributes(i);
 278
 279       Record.push_back(VE.getAttributeGroupID(A));
 280       Record.push_back(AS.getSlotIndex(i));
 281
 282       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 283            I != E; ++I) {
 284         Attribute Attr = *I;
 285         if (Attr.isEnumAttribute()) {
 286           Record.push_back(0);
 287           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 288         } else if (Attr.isIntAttribute()) {
 289           Record.push_back(1);
 290           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 291           Record.push_back(Attr.getValueAsInt());
 292         } else {
 293           StringRef Kind = Attr.getKindAsString();
 294           StringRef Val = Attr.getValueAsString();
 295
 296           Record.push_back(Val.empty() ? 3 : 4);
 297           Record.append(Kind.begin(), Kind.end());
 298           Record.push_back(0);
 299           if (!Val.empty()) {
 300             Record.append(Val.begin(), Val.end());
 301             Record.push_back(0);
 302           }
 303         }
 304       }
 305
 306       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 307       Record.clear();
 308     }
 309   }
 310
 311   Stream.ExitBlock();
 312 }
 313
 314 static void WriteAttributeTable(const ValueEnumerator &VE,
 315                                 BitstreamWriter &Stream) {
 316   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 317   if (Attrs.empty()) return;
 318
 319   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 320
 321   SmallVector<uint64_t, 64> Record;
 322   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 323     const AttributeSet &A = Attrs[i];
 324     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 325       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 326
 327     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 328     Record.clear();
 329   }
 330
 331   Stream.ExitBlock();
 332 }
 333
 334 /// WriteTypeTable - Write out the type table for a module.
 335 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 336   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 337
 338   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 339   SmallVector<uint64_t, 64> TypeVals;
 340
 341   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 342
 343   // Abbrev for TYPE_CODE_POINTER.
 344   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 345   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 346   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 347   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 348   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 349
 350   // Abbrev for TYPE_CODE_FUNCTION.
 351   Abbv = new BitCodeAbbrev();
 352   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 356
 357   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 358
 359   // Abbrev for TYPE_CODE_STRUCT_ANON.
 360   Abbv = new BitCodeAbbrev();
 361   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 365
 366   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 367
 368   // Abbrev for TYPE_CODE_STRUCT_NAME.
 369   Abbv = new BitCodeAbbrev();
 370   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 373   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 374
 375   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 376   Abbv = new BitCodeAbbrev();
 377   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 378   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 379   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 381
 382   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 383
 384   // Abbrev for TYPE_CODE_ARRAY.
 385   Abbv = new BitCodeAbbrev();
 386   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 388   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 389
 390   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 391
 392   // Emit an entry count so the reader can reserve space.
 393   TypeVals.push_back(TypeList.size());
 394   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 395   TypeVals.clear();
 396
 397   // Loop over all of the types, emitting each in turn.
 398   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 399     Type *T = TypeList[i];
 400     int AbbrevToUse = 0;
 401     unsigned Code = 0;
 402
 403     switch (T->getTypeID()) {
 404     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 405     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 406     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 407     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 408     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 409     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 410     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 411     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 412     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 413     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 414     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
 415     case Type::IntegerTyID:
 416       // INTEGER: [width]
 417       Code = bitc::TYPE_CODE_INTEGER;
 418       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 419       break;
 420     case Type::PointerTyID: {
 421       PointerType *PTy = cast<PointerType>(T);
 422       // POINTER: [pointee type, address space]
 423       Code = bitc::TYPE_CODE_POINTER;
 424       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 425       unsigned AddressSpace = PTy->getAddressSpace();
 426       TypeVals.push_back(AddressSpace);
 427       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 428       break;
 429     }
 430     case Type::FunctionTyID: {
 431       FunctionType *FT = cast<FunctionType>(T);
 432       // FUNCTION: [isvararg, retty, paramty x N]
 433       Code = bitc::TYPE_CODE_FUNCTION;
 434       TypeVals.push_back(FT->isVarArg());
 435       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 436       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 437         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 438       AbbrevToUse = FunctionAbbrev;
 439       break;
 440     }
 441     case Type::StructTyID: {
 442       StructType *ST = cast<StructType>(T);
 443       // STRUCT: [ispacked, eltty x N]
 444       TypeVals.push_back(ST->isPacked());
 445       // Output all of the element types.
 446       for (StructType::element_iterator I = ST->element_begin(),
 447            E = ST->element_end(); I != E; ++I)
 448         TypeVals.push_back(VE.getTypeID(*I));
 449
 450       if (ST->isLiteral()) {
 451         Code = bitc::TYPE_CODE_STRUCT_ANON;
 452         AbbrevToUse = StructAnonAbbrev;
 453       } else {
 454         if (ST->isOpaque()) {
 455           Code = bitc::TYPE_CODE_OPAQUE;
 456         } else {
 457           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 458           AbbrevToUse = StructNamedAbbrev;
 459         }
 460
 461         // Emit the name if it is present.
 462         if (!ST->getName().empty())
 463           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 464                             StructNameAbbrev, Stream);
 465       }
 466       break;
 467     }
 468     case Type::ArrayTyID: {
 469       ArrayType *AT = cast<ArrayType>(T);
 470       // ARRAY: [numelts, eltty]
 471       Code = bitc::TYPE_CODE_ARRAY;
 472       TypeVals.push_back(AT->getNumElements());
 473       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 474       AbbrevToUse = ArrayAbbrev;
 475       break;
 476     }
 477     case Type::VectorTyID: {
 478       VectorType *VT = cast<VectorType>(T);
 479       // VECTOR [numelts, eltty]
 480       Code = bitc::TYPE_CODE_VECTOR;
 481       TypeVals.push_back(VT->getNumElements());
 482       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 483       break;
 484     }
 485     }
 486
 487     // Emit the finished record.
 488     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 489     TypeVals.clear();
 490   }
 491
 492   Stream.ExitBlock();
 493 }
 494
 495 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 496   switch (GV.getLinkage()) {
 497   case GlobalValue::ExternalLinkage:
 498     return 0;
 499   case GlobalValue::WeakAnyLinkage:
 500     return 16;
 501   case GlobalValue::AppendingLinkage:
 502     return 2;
 503   case GlobalValue::InternalLinkage:
 504     return 3;
 505   case GlobalValue::LinkOnceAnyLinkage:
 506     return 18;
 507   case GlobalValue::ExternalWeakLinkage:
 508     return 7;
 509   case GlobalValue::CommonLinkage:
 510     return 8;
 511   case GlobalValue::PrivateLinkage:
 512     return 9;
 513   case GlobalValue::WeakODRLinkage:
 514     return 17;
 515   case GlobalValue::LinkOnceODRLinkage:
 516     return 19;
 517   case GlobalValue::AvailableExternallyLinkage:
 518     return 12;
 519   }
 520   llvm_unreachable("Invalid linkage");
 521 }
 522
 523 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 524   switch (GV.getVisibility()) {
 525   case GlobalValue::DefaultVisibility:   return 0;
 526   case GlobalValue::HiddenVisibility:    return 1;
 527   case GlobalValue::ProtectedVisibility: return 2;
 528   }
 529   llvm_unreachable("Invalid visibility");
 530 }
 531
 532 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 533   switch (GV.getDLLStorageClass()) {
 534   case GlobalValue::DefaultStorageClass:   return 0;
 535   case GlobalValue::DLLImportStorageClass: return 1;
 536   case GlobalValue::DLLExportStorageClass: return 2;
 537   }
 538   llvm_unreachable("Invalid DLL storage class");
 539 }
 540
 541 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 542   switch (GV.getThreadLocalMode()) {
 543     case GlobalVariable::NotThreadLocal:         return 0;
 544     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 545     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 546     case GlobalVariable::InitialExecTLSModel:    return 3;
 547     case GlobalVariable::LocalExecTLSModel:      return 4;
 548   }
 549   llvm_unreachable("Invalid TLS model");
 550 }
 551
 552 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 553   switch (C.getSelectionKind()) {
 554   case Comdat::Any:
 555     return bitc::COMDAT_SELECTION_KIND_ANY;
 556   case Comdat::ExactMatch:
 557     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 558   case Comdat::Largest:
 559     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 560   case Comdat::NoDuplicates:
 561     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 562   case Comdat::SameSize:
 563     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 564   }
 565   llvm_unreachable("Invalid selection kind");
 566 }
 567
 568 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 569   SmallVector<uint16_t, 64> Vals;
 570   for (const Comdat *C : VE.getComdats()) {
 571     // COMDAT: [selection_kind, name]
 572     Vals.push_back(getEncodedComdatSelectionKind(*C));
 573     size_t Size = C->getName().size();
 574     assert(isUInt<16>(Size));
 575     Vals.push_back(Size);
 576     for (char Chr : C->getName())
 577       Vals.push_back((unsigned char)Chr);
 578     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 579     Vals.clear();
 580   }
 581 }
 582
 583 /// Write a record that will eventually hold the word offset of the
 584 /// module-level VST. For now the offset is 0, which will be backpatched
 585 /// after the real VST is written. Returns the bit offset to backpatch.
 586 static uint64_t WriteValueSymbolTableForwardDecl(const ValueSymbolTable &VST,
 587                                                  BitstreamWriter &Stream) {
 588   if (VST.empty())
 589     return 0;
 590
 591   // Write a placeholder value in for the offset of the real VST,
 592   // which is written after the function blocks so that it can include
 593   // the offset of each function. The placeholder offset will be
 594   // updated when the real VST is written.
 595   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 596   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
 597   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
 598   // hold the real VST offset. Must use fixed instead of VBR as we don't
 599   // know how many VBR chunks to reserve ahead of time.
 600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
 601   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
 602
 603   // Emit the placeholder
 604   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
 605   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
 606
 607   // Compute and return the bit offset to the placeholder, which will be
 608   // patched when the real VST is written. We can simply subtract the 32-bit
 609   // fixed size from the current bit number to get the location to backpatch.
 610   return Stream.GetCurrentBitNo() - 32;
 611 }
 612
 613 /// Emit top-level description of module, including target triple, inline asm,
 614 /// descriptors for global variables, and function prototype info.
 615 /// Returns the bit offset to backpatch with the location of the real VST.
 616 static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 617                                 BitstreamWriter &Stream) {
 618   // Emit various pieces of data attached to a module.
 619   if (!M->getTargetTriple().empty())
 620     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 621                       0/*TODO*/, Stream);
 622   const std::string &DL = M->getDataLayoutStr();
 623   if (!DL.empty())
 624     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 625   if (!M->getModuleInlineAsm().empty())
 626     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 627                       0/*TODO*/, Stream);
 628
 629   // Emit information about sections and GC, computing how many there are. Also
 630   // compute the maximum alignment value.
 631   std::map<std::string, unsigned> SectionMap;
 632   std::map<std::string, unsigned> GCMap;
 633   unsigned MaxAlignment = 0;
 634   unsigned MaxGlobalType = 0;
 635   for (const GlobalValue &GV : M->globals()) {
 636     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 637     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 638     if (GV.hasSection()) {
 639       // Give section names unique ID's.
 640       unsigned &Entry = SectionMap[GV.getSection()];
 641       if (!Entry) {
 642         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 643                           0/*TODO*/, Stream);
 644         Entry = SectionMap.size();
 645       }
 646     }
 647   }
 648   for (const Function &F : *M) {
 649     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 650     if (F.hasSection()) {
 651       // Give section names unique ID's.
 652       unsigned &Entry = SectionMap[F.getSection()];
 653       if (!Entry) {
 654         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 655                           0/*TODO*/, Stream);
 656         Entry = SectionMap.size();
 657       }
 658     }
 659     if (F.hasGC()) {
 660       // Same for GC names.
 661       unsigned &Entry = GCMap[F.getGC()];
 662       if (!Entry) {
 663         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 664                           0/*TODO*/, Stream);
 665         Entry = GCMap.size();
 666       }
 667     }
 668   }
 669
 670   // Emit abbrev for globals, now that we know # sections and max alignment.
 671   unsigned SimpleGVarAbbrev = 0;
 672   if (!M->global_empty()) {
 673     // Add an abbrev for common globals with no visibility or thread localness.
 674     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 675     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 677                               Log2_32_Ceil(MaxGlobalType+1)));
 678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 679                                                            //| explicitType << 1
 680                                                            //| constant
 681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 682     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 683     if (MaxAlignment == 0)                                 // Alignment.
 684       Abbv->Add(BitCodeAbbrevOp(0));
 685     else {
 686       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 687       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 688                                Log2_32_Ceil(MaxEncAlignment+1)));
 689     }
 690     if (SectionMap.empty())                                    // Section.
 691       Abbv->Add(BitCodeAbbrevOp(0));
 692     else
 693       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 694                                Log2_32_Ceil(SectionMap.size()+1)));
 695     // Don't bother emitting vis + thread local.
 696     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 697   }
 698
 699   // Emit the global variable information.
 700   SmallVector<unsigned, 64> Vals;
 701   for (const GlobalVariable &GV : M->globals()) {
 702     unsigned AbbrevToUse = 0;
 703
 704     // GLOBALVAR: [type, isconst, initid,
 705     //             linkage, alignment, section, visibility, threadlocal,
 706     //             unnamed_addr, externally_initialized, dllstorageclass,
 707     //             comdat]
 708     Vals.push_back(VE.getTypeID(GV.getValueType()));
 709     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 710     Vals.push_back(GV.isDeclaration() ? 0 :
 711                    (VE.getValueID(GV.getInitializer()) + 1));
 712     Vals.push_back(getEncodedLinkage(GV));
 713     Vals.push_back(Log2_32(GV.getAlignment())+1);
 714     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 715     if (GV.isThreadLocal() ||
 716         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 717         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 718         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 719         GV.hasComdat()) {
 720       Vals.push_back(getEncodedVisibility(GV));
 721       Vals.push_back(getEncodedThreadLocalMode(GV));
 722       Vals.push_back(GV.hasUnnamedAddr());
 723       Vals.push_back(GV.isExternallyInitialized());
 724       Vals.push_back(getEncodedDLLStorageClass(GV));
 725       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 726     } else {
 727       AbbrevToUse = SimpleGVarAbbrev;
 728     }
 729
 730     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 731     Vals.clear();
 732   }
 733
 734   // Emit the function proto information.
 735   for (const Function &F : *M) {
 736     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 737     //             section, visibility, gc, unnamed_addr, prologuedata,
 738     //             dllstorageclass, comdat, prefixdata, personalityfn]
 739     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 740     Vals.push_back(F.getCallingConv());
 741     Vals.push_back(F.isDeclaration());
 742     Vals.push_back(getEncodedLinkage(F));
 743     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 744     Vals.push_back(Log2_32(F.getAlignment())+1);
 745     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 746     Vals.push_back(getEncodedVisibility(F));
 747     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 748     Vals.push_back(F.hasUnnamedAddr());
 749     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 750                                        : 0);
 751     Vals.push_back(getEncodedDLLStorageClass(F));
 752     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 753     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 754                                      : 0);
 755     Vals.push_back(
 756         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
 757
 758     unsigned AbbrevToUse = 0;
 759     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 760     Vals.clear();
 761   }
 762
 763   // Emit the alias information.
 764   for (const GlobalAlias &A : M->aliases()) {
 765     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 766     Vals.push_back(VE.getTypeID(A.getValueType()));
 767     Vals.push_back(A.getType()->getAddressSpace());
 768     Vals.push_back(VE.getValueID(A.getAliasee()));
 769     Vals.push_back(getEncodedLinkage(A));
 770     Vals.push_back(getEncodedVisibility(A));
 771     Vals.push_back(getEncodedDLLStorageClass(A));
 772     Vals.push_back(getEncodedThreadLocalMode(A));
 773     Vals.push_back(A.hasUnnamedAddr());
 774     unsigned AbbrevToUse = 0;
 775     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 776     Vals.clear();
 777   }
 778
 779   // Write a record indicating the number of module-level metadata IDs
 780   // This is needed because the ids of metadata are assigned implicitly
 781   // based on their ordering in the bitcode, with the function-level
 782   // metadata ids starting after the module-level metadata ids. For
 783   // function importing where we lazy load the metadata as a postpass,
 784   // we want to avoid parsing the module-level metadata before parsing
 785   // the imported functions.
 786   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 787   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_METADATA_VALUES));
 788   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 789   unsigned MDValsAbbrev = Stream.EmitAbbrev(Abbv);
 790   Vals.push_back(VE.numMDs());
 791   Stream.EmitRecord(bitc::MODULE_CODE_METADATA_VALUES, Vals, MDValsAbbrev);
 792   Vals.clear();
 793
 794   uint64_t VSTOffsetPlaceholder =
 795       WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
 796   return VSTOffsetPlaceholder;
 797 }
 798
 799 static uint64_t GetOptimizationFlags(const Value *V) {
 800   uint64_t Flags = 0;
 801
 802   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 803     if (OBO->hasNoSignedWrap())
 804       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 805     if (OBO->hasNoUnsignedWrap())
 806       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 807   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 808     if (PEO->isExact())
 809       Flags |= 1 << bitc::PEO_EXACT;
 810   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 811     if (FPMO->hasUnsafeAlgebra())
 812       Flags |= FastMathFlags::UnsafeAlgebra;
 813     if (FPMO->hasNoNaNs())
 814       Flags |= FastMathFlags::NoNaNs;
 815     if (FPMO->hasNoInfs())
 816       Flags |= FastMathFlags::NoInfs;
 817     if (FPMO->hasNoSignedZeros())
 818       Flags |= FastMathFlags::NoSignedZeros;
 819     if (FPMO->hasAllowReciprocal())
 820       Flags |= FastMathFlags::AllowReciprocal;
 821   }
 822
 823   return Flags;
 824 }
 825
 826 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 827                                  const ValueEnumerator &VE,
 828                                  BitstreamWriter &Stream,
 829                                  SmallVectorImpl<uint64_t> &Record) {
 830   // Mimic an MDNode with a value as one operand.
 831   Value *V = MD->getValue();
 832   Record.push_back(VE.getTypeID(V->getType()));
 833   Record.push_back(VE.getValueID(V));
 834   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 835   Record.clear();
 836 }
 837
 838 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 839                          BitstreamWriter &Stream,
 840                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 841   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 842     Metadata *MD = N->getOperand(i);
 843     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 844            "Unexpected function-local metadata");
 845     Record.push_back(VE.getMetadataOrNullID(MD));
 846   }
 847   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 848                                     : bitc::METADATA_NODE,
 849                     Record, Abbrev);
 850   Record.clear();
 851 }
 852
 853 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 854                             BitstreamWriter &Stream,
 855                             SmallVectorImpl<uint64_t> &Record,
 856                             unsigned Abbrev) {
 857   Record.push_back(N->isDistinct());
 858   Record.push_back(N->getLine());
 859   Record.push_back(N->getColumn());
 860   Record.push_back(VE.getMetadataID(N->getScope()));
 861   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 862
 863   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 864   Record.clear();
 865 }
 866
 867 static void WriteGenericDINode(const GenericDINode *N,
 868                                const ValueEnumerator &VE,
 869                                BitstreamWriter &Stream,
 870                                SmallVectorImpl<uint64_t> &Record,
 871                                unsigned Abbrev) {
 872   Record.push_back(N->isDistinct());
 873   Record.push_back(N->getTag());
 874   Record.push_back(0); // Per-tag version field; unused for now.
 875
 876   for (auto &I : N->operands())
 877     Record.push_back(VE.getMetadataOrNullID(I));
 878
 879   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 880   Record.clear();
 881 }
 882
 883 static uint64_t rotateSign(int64_t I) {
 884   uint64_t U = I;
 885   return I < 0 ? ~(U << 1) : U << 1;
 886 }
 887
 888 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 889                             BitstreamWriter &Stream,
 890                             SmallVectorImpl<uint64_t> &Record,
 891                             unsigned Abbrev) {
 892   Record.push_back(N->isDistinct());
 893   Record.push_back(N->getCount());
 894   Record.push_back(rotateSign(N->getLowerBound()));
 895
 896   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 897   Record.clear();
 898 }
 899
 900 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 901                               BitstreamWriter &Stream,
 902                               SmallVectorImpl<uint64_t> &Record,
 903                               unsigned Abbrev) {
 904   Record.push_back(N->isDistinct());
 905   Record.push_back(rotateSign(N->getValue()));
 906   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 907
 908   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 909   Record.clear();
 910 }
 911
 912 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 913                              BitstreamWriter &Stream,
 914                              SmallVectorImpl<uint64_t> &Record,
 915                              unsigned Abbrev) {
 916   Record.push_back(N->isDistinct());
 917   Record.push_back(N->getTag());
 918   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 919   Record.push_back(N->getSizeInBits());
 920   Record.push_back(N->getAlignInBits());
 921   Record.push_back(N->getEncoding());
 922
 923   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 924   Record.clear();
 925 }
 926
 927 static void WriteDIDerivedType(const DIDerivedType *N,
 928                                const ValueEnumerator &VE,
 929                                BitstreamWriter &Stream,
 930                                SmallVectorImpl<uint64_t> &Record,
 931                                unsigned Abbrev) {
 932   Record.push_back(N->isDistinct());
 933   Record.push_back(N->getTag());
 934   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 935   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 936   Record.push_back(N->getLine());
 937   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 938   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 939   Record.push_back(N->getSizeInBits());
 940   Record.push_back(N->getAlignInBits());
 941   Record.push_back(N->getOffsetInBits());
 942   Record.push_back(N->getFlags());
 943   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 944
 945   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 946   Record.clear();
 947 }
 948
 949 static void WriteDICompositeType(const DICompositeType *N,
 950                                  const ValueEnumerator &VE,
 951                                  BitstreamWriter &Stream,
 952                                  SmallVectorImpl<uint64_t> &Record,
 953                                  unsigned Abbrev) {
 954   Record.push_back(N->isDistinct());
 955   Record.push_back(N->getTag());
 956   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 957   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 958   Record.push_back(N->getLine());
 959   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 960   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 961   Record.push_back(N->getSizeInBits());
 962   Record.push_back(N->getAlignInBits());
 963   Record.push_back(N->getOffsetInBits());
 964   Record.push_back(N->getFlags());
 965   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 966   Record.push_back(N->getRuntimeLang());
 967   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 968   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 969   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 970
 971   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 972   Record.clear();
 973 }
 974
 975 static void WriteDISubroutineType(const DISubroutineType *N,
 976                                   const ValueEnumerator &VE,
 977                                   BitstreamWriter &Stream,
 978                                   SmallVectorImpl<uint64_t> &Record,
 979                                   unsigned Abbrev) {
 980   Record.push_back(N->isDistinct());
 981   Record.push_back(N->getFlags());
 982   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 983
 984   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 985   Record.clear();
 986 }
 987
 988 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 989                         BitstreamWriter &Stream,
 990                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 991   Record.push_back(N->isDistinct());
 992   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 993   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 994
 995   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 996   Record.clear();
 997 }
 998
 999 static void WriteDICompileUnit(const DICompileUnit *N,
1000                                const ValueEnumerator &VE,
1001                                BitstreamWriter &Stream,
1002                                SmallVectorImpl<uint64_t> &Record,
1003                                unsigned Abbrev) {
1004   assert(N->isDistinct() && "Expected distinct compile units");
1005   Record.push_back(/* IsDistinct */ true);
1006   Record.push_back(N->getSourceLanguage());
1007   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1008   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1009   Record.push_back(N->isOptimized());
1010   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1011   Record.push_back(N->getRuntimeVersion());
1012   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1013   Record.push_back(N->getEmissionKind());
1014   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1015   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1016   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
1017   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1018   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1019   Record.push_back(N->getDWOId());
1020   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1021
1022   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1023   Record.clear();
1024 }
1025
1026 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1027                               BitstreamWriter &Stream,
1028                               SmallVectorImpl<uint64_t> &Record,
1029                               unsigned Abbrev) {
1030   Record.push_back(N->isDistinct());
1031   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1032   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1033   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1034   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1035   Record.push_back(N->getLine());
1036   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1037   Record.push_back(N->isLocalToUnit());
1038   Record.push_back(N->isDefinition());
1039   Record.push_back(N->getScopeLine());
1040   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1041   Record.push_back(N->getVirtuality());
1042   Record.push_back(N->getVirtualIndex());
1043   Record.push_back(N->getFlags());
1044   Record.push_back(N->isOptimized());
1045   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1046   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1047   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1048
1049   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1050   Record.clear();
1051 }
1052
1053 static void WriteDILexicalBlock(const DILexicalBlock *N,
1054                                 const ValueEnumerator &VE,
1055                                 BitstreamWriter &Stream,
1056                                 SmallVectorImpl<uint64_t> &Record,
1057                                 unsigned Abbrev) {
1058   Record.push_back(N->isDistinct());
1059   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1060   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1061   Record.push_back(N->getLine());
1062   Record.push_back(N->getColumn());
1063
1064   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1065   Record.clear();
1066 }
1067
1068 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1069                                     const ValueEnumerator &VE,
1070                                     BitstreamWriter &Stream,
1071                                     SmallVectorImpl<uint64_t> &Record,
1072                                     unsigned Abbrev) {
1073   Record.push_back(N->isDistinct());
1074   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1075   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1076   Record.push_back(N->getDiscriminator());
1077
1078   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1079   Record.clear();
1080 }
1081
1082 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1083                              BitstreamWriter &Stream,
1084                              SmallVectorImpl<uint64_t> &Record,
1085                              unsigned Abbrev) {
1086   Record.push_back(N->isDistinct());
1087   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1088   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1089   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1090   Record.push_back(N->getLine());
1091
1092   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1093   Record.clear();
1094 }
1095
1096 static void WriteDIMacro(const DIMacro *N, const ValueEnumerator &VE,
1097                          BitstreamWriter &Stream,
1098                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1099   Record.push_back(N->isDistinct());
1100   Record.push_back(N->getMacinfoType());
1101   Record.push_back(N->getLine());
1102   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1103   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1104
1105   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1106   Record.clear();
1107 }
1108
1109 static void WriteDIMacroFile(const DIMacroFile *N, const ValueEnumerator &VE,
1110                              BitstreamWriter &Stream,
1111                              SmallVectorImpl<uint64_t> &Record,
1112                              unsigned Abbrev) {
1113   Record.push_back(N->isDistinct());
1114   Record.push_back(N->getMacinfoType());
1115   Record.push_back(N->getLine());
1116   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1117   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1118
1119   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1120   Record.clear();
1121 }
1122
1123 static void WriteDIModule(const DIModule *N, const ValueEnumerator &VE,
1124                           BitstreamWriter &Stream,
1125                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1126   Record.push_back(N->isDistinct());
1127   for (auto &I : N->operands())
1128     Record.push_back(VE.getMetadataOrNullID(I));
1129
1130   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1131   Record.clear();
1132 }
1133
1134 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1135                                          const ValueEnumerator &VE,
1136                                          BitstreamWriter &Stream,
1137                                          SmallVectorImpl<uint64_t> &Record,
1138                                          unsigned Abbrev) {
1139   Record.push_back(N->isDistinct());
1140   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1141   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1142
1143   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1144   Record.clear();
1145 }
1146
1147 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1148                                           const ValueEnumerator &VE,
1149                                           BitstreamWriter &Stream,
1150                                           SmallVectorImpl<uint64_t> &Record,
1151                                           unsigned Abbrev) {
1152   Record.push_back(N->isDistinct());
1153   Record.push_back(N->getTag());
1154   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1155   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1156   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1157
1158   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1159   Record.clear();
1160 }
1161
1162 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1163                                   const ValueEnumerator &VE,
1164                                   BitstreamWriter &Stream,
1165                                   SmallVectorImpl<uint64_t> &Record,
1166                                   unsigned Abbrev) {
1167   Record.push_back(N->isDistinct());
1168   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1169   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1170   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1171   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1172   Record.push_back(N->getLine());
1173   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1174   Record.push_back(N->isLocalToUnit());
1175   Record.push_back(N->isDefinition());
1176   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1177   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1178
1179   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1180   Record.clear();
1181 }
1182
1183 static void WriteDILocalVariable(const DILocalVariable *N,
1184                                  const ValueEnumerator &VE,
1185                                  BitstreamWriter &Stream,
1186                                  SmallVectorImpl<uint64_t> &Record,
1187                                  unsigned Abbrev) {
1188   Record.push_back(N->isDistinct());
1189   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1190   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1191   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1192   Record.push_back(N->getLine());
1193   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1194   Record.push_back(N->getArg());
1195   Record.push_back(N->getFlags());
1196
1197   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1198   Record.clear();
1199 }
1200
1201 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1202                               BitstreamWriter &Stream,
1203                               SmallVectorImpl<uint64_t> &Record,
1204                               unsigned Abbrev) {
1205   Record.reserve(N->getElements().size() + 1);
1206
1207   Record.push_back(N->isDistinct());
1208   Record.append(N->elements_begin(), N->elements_end());
1209
1210   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1211   Record.clear();
1212 }
1213
1214 static void WriteDIObjCProperty(const DIObjCProperty *N,
1215                                 const ValueEnumerator &VE,
1216                                 BitstreamWriter &Stream,
1217                                 SmallVectorImpl<uint64_t> &Record,
1218                                 unsigned Abbrev) {
1219   Record.push_back(N->isDistinct());
1220   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1221   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1222   Record.push_back(N->getLine());
1223   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1224   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1225   Record.push_back(N->getAttributes());
1226   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1227
1228   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1229   Record.clear();
1230 }
1231
1232 static void WriteDIImportedEntity(const DIImportedEntity *N,
1233                                   const ValueEnumerator &VE,
1234                                   BitstreamWriter &Stream,
1235                                   SmallVectorImpl<uint64_t> &Record,
1236                                   unsigned Abbrev) {
1237   Record.push_back(N->isDistinct());
1238   Record.push_back(N->getTag());
1239   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1240   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1241   Record.push_back(N->getLine());
1242   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1243
1244   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1245   Record.clear();
1246 }
1247
1248 static void WriteModuleMetadata(const Module *M,
1249                                 const ValueEnumerator &VE,
1250                                 BitstreamWriter &Stream) {
1251   const auto &MDs = VE.getMDs();
1252   if (MDs.empty() && M->named_metadata_empty())
1253     return;
1254
1255   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1256
1257   unsigned MDSAbbrev = 0;
1258   if (VE.hasMDString()) {
1259     // Abbrev for METADATA_STRING.
1260     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1261     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1262     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1263     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1264     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1265   }
1266
1267   // Initialize MDNode abbreviations.
1268 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1269 #include "llvm/IR/Metadata.def"
1270
1271   if (VE.hasDILocation()) {
1272     // Abbrev for METADATA_LOCATION.
1273     //
1274     // Assume the column is usually under 128, and always output the inlined-at
1275     // location (it's never more expensive than building an array size 1).
1276     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1277     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1283     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1284   }
1285
1286   if (VE.hasGenericDINode()) {
1287     // Abbrev for METADATA_GENERIC_DEBUG.
1288     //
1289     // Assume the column is usually under 128, and always output the inlined-at
1290     // location (it's never more expensive than building an array size 1).
1291     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1292     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1297     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1299     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1300   }
1301
1302   unsigned NameAbbrev = 0;
1303   if (!M->named_metadata_empty()) {
1304     // Abbrev for METADATA_NAME.
1305     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1306     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1309     NameAbbrev = Stream.EmitAbbrev(Abbv);
1310   }
1311
1312   SmallVector<uint64_t, 64> Record;
1313   for (const Metadata *MD : MDs) {
1314     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1315       assert(N->isResolved() && "Expected forward references to be resolved");
1316
1317       switch (N->getMetadataID()) {
1318       default:
1319         llvm_unreachable("Invalid MDNode subclass");
1320 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1321   case Metadata::CLASS##Kind:                                                  \
1322     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1323     continue;
1324 #include "llvm/IR/Metadata.def"
1325       }
1326     }
1327     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1328       WriteValueAsMetadata(MDC, VE, Stream, Record);
1329       continue;
1330     }
1331     const MDString *MDS = cast<MDString>(MD);
1332     // Code: [strchar x N]
1333     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1334
1335     // Emit the finished record.
1336     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1337     Record.clear();
1338   }
1339
1340   // Write named metadata.
1341   for (const NamedMDNode &NMD : M->named_metadata()) {
1342     // Write name.
1343     StringRef Str = NMD.getName();
1344     Record.append(Str.bytes_begin(), Str.bytes_end());
1345     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1346     Record.clear();
1347
1348     // Write named metadata operands.
1349     for (const MDNode *N : NMD.operands())
1350       Record.push_back(VE.getMetadataID(N));
1351     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1352     Record.clear();
1353   }
1354
1355   Stream.ExitBlock();
1356 }
1357
1358 static void WriteFunctionLocalMetadata(const Function &F,
1359                                        const ValueEnumerator &VE,
1360                                        BitstreamWriter &Stream) {
1361   bool StartedMetadataBlock = false;
1362   SmallVector<uint64_t, 64> Record;
1363   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1364       VE.getFunctionLocalMDs();
1365   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1366     assert(MDs[i] && "Expected valid function-local metadata");
1367     if (!StartedMetadataBlock) {
1368       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1369       StartedMetadataBlock = true;
1370     }
1371     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1372   }
1373
1374   if (StartedMetadataBlock)
1375     Stream.ExitBlock();
1376 }
1377
1378 static void WriteMetadataAttachment(const Function &F,
1379                                     const ValueEnumerator &VE,
1380                                     BitstreamWriter &Stream) {
1381   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1382
1383   SmallVector<uint64_t, 64> Record;
1384
1385   // Write metadata attachments
1386   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1387   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1388   F.getAllMetadata(MDs);
1389   if (!MDs.empty()) {
1390     for (const auto &I : MDs) {
1391       Record.push_back(I.first);
1392       Record.push_back(VE.getMetadataID(I.second));
1393     }
1394     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1395     Record.clear();
1396   }
1397
1398   for (const BasicBlock &BB : F)
1399     for (const Instruction &I : BB) {
1400       MDs.clear();
1401       I.getAllMetadataOtherThanDebugLoc(MDs);
1402
1403       // If no metadata, ignore instruction.
1404       if (MDs.empty()) continue;
1405
1406       Record.push_back(VE.getInstructionID(&I));
1407
1408       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1409         Record.push_back(MDs[i].first);
1410         Record.push_back(VE.getMetadataID(MDs[i].second));
1411       }
1412       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1413       Record.clear();
1414     }
1415
1416   Stream.ExitBlock();
1417 }
1418
1419 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1420   SmallVector<uint64_t, 64> Record;
1421
1422   // Write metadata kinds
1423   // METADATA_KIND - [n x [id, name]]
1424   SmallVector<StringRef, 8> Names;
1425   M->getMDKindNames(Names);
1426
1427   if (Names.empty()) return;
1428
1429   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1430
1431   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1432     Record.push_back(MDKindID);
1433     StringRef KName = Names[MDKindID];
1434     Record.append(KName.begin(), KName.end());
1435
1436     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1437     Record.clear();
1438   }
1439
1440   Stream.ExitBlock();
1441 }
1442
1443 static void WriteOperandBundleTags(const Module *M, BitstreamWriter &Stream) {
1444   // Write metadata kinds
1445   //
1446   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1447   //
1448   // OPERAND_BUNDLE_TAG - [strchr x N]
1449
1450   SmallVector<StringRef, 8> Tags;
1451   M->getOperandBundleTags(Tags);
1452
1453   if (Tags.empty())
1454     return;
1455
1456   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1457
1458   SmallVector<uint64_t, 64> Record;
1459
1460   for (auto Tag : Tags) {
1461     Record.append(Tag.begin(), Tag.end());
1462
1463     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1464     Record.clear();
1465   }
1466
1467   Stream.ExitBlock();
1468 }
1469
1470 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1471   if ((int64_t)V >= 0)
1472     Vals.push_back(V << 1);
1473   else
1474     Vals.push_back((-V << 1) | 1);
1475 }
1476
1477 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1478                            const ValueEnumerator &VE,
1479                            BitstreamWriter &Stream, bool isGlobal) {
1480   if (FirstVal == LastVal) return;
1481
1482   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1483
1484   unsigned AggregateAbbrev = 0;
1485   unsigned String8Abbrev = 0;
1486   unsigned CString7Abbrev = 0;
1487   unsigned CString6Abbrev = 0;
1488   // If this is a constant pool for the module, emit module-specific abbrevs.
1489   if (isGlobal) {
1490     // Abbrev for CST_CODE_AGGREGATE.
1491     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1492     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1495     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1496
1497     // Abbrev for CST_CODE_STRING.
1498     Abbv = new BitCodeAbbrev();
1499     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1502     String8Abbrev = Stream.EmitAbbrev(Abbv);
1503     // Abbrev for CST_CODE_CSTRING.
1504     Abbv = new BitCodeAbbrev();
1505     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1508     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1509     // Abbrev for CST_CODE_CSTRING.
1510     Abbv = new BitCodeAbbrev();
1511     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1514     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1515   }
1516
1517   SmallVector<uint64_t, 64> Record;
1518
1519   const ValueEnumerator::ValueList &Vals = VE.getValues();
1520   Type *LastTy = nullptr;
1521   for (unsigned i = FirstVal; i != LastVal; ++i) {
1522     const Value *V = Vals[i].first;
1523     // If we need to switch types, do so now.
1524     if (V->getType() != LastTy) {
1525       LastTy = V->getType();
1526       Record.push_back(VE.getTypeID(LastTy));
1527       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1528                         CONSTANTS_SETTYPE_ABBREV);
1529       Record.clear();
1530     }
1531
1532     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1533       Record.push_back(unsigned(IA->hasSideEffects()) |
1534                        unsigned(IA->isAlignStack()) << 1 |
1535                        unsigned(IA->getDialect()&1) << 2);
1536
1537       // Add the asm string.
1538       const std::string &AsmStr = IA->getAsmString();
1539       Record.push_back(AsmStr.size());
1540       Record.append(AsmStr.begin(), AsmStr.end());
1541
1542       // Add the constraint string.
1543       const std::string &ConstraintStr = IA->getConstraintString();
1544       Record.push_back(ConstraintStr.size());
1545       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1546       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1547       Record.clear();
1548       continue;
1549     }
1550     const Constant *C = cast<Constant>(V);
1551     unsigned Code = -1U;
1552     unsigned AbbrevToUse = 0;
1553     if (C->isNullValue()) {
1554       Code = bitc::CST_CODE_NULL;
1555     } else if (isa<UndefValue>(C)) {
1556       Code = bitc::CST_CODE_UNDEF;
1557     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1558       if (IV->getBitWidth() <= 64) {
1559         uint64_t V = IV->getSExtValue();
1560         emitSignedInt64(Record, V);
1561         Code = bitc::CST_CODE_INTEGER;
1562         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1563       } else {                             // Wide integers, > 64 bits in size.
1564         // We have an arbitrary precision integer value to write whose
1565         // bit width is > 64. However, in canonical unsigned integer
1566         // format it is likely that the high bits are going to be zero.
1567         // So, we only write the number of active words.
1568         unsigned NWords = IV->getValue().getActiveWords();
1569         const uint64_t *RawWords = IV->getValue().getRawData();
1570         for (unsigned i = 0; i != NWords; ++i) {
1571           emitSignedInt64(Record, RawWords[i]);
1572         }
1573         Code = bitc::CST_CODE_WIDE_INTEGER;
1574       }
1575     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1576       Code = bitc::CST_CODE_FLOAT;
1577       Type *Ty = CFP->getType();
1578       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1579         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1580       } else if (Ty->isX86_FP80Ty()) {
1581         // api needed to prevent premature destruction
1582         // bits are not in the same order as a normal i80 APInt, compensate.
1583         APInt api = CFP->getValueAPF().bitcastToAPInt();
1584         const uint64_t *p = api.getRawData();
1585         Record.push_back((p[1] << 48) | (p[0] >> 16));
1586         Record.push_back(p[0] & 0xffffLL);
1587       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1588         APInt api = CFP->getValueAPF().bitcastToAPInt();
1589         const uint64_t *p = api.getRawData();
1590         Record.push_back(p[0]);
1591         Record.push_back(p[1]);
1592       } else {
1593         assert (0 && "Unknown FP type!");
1594       }
1595     } else if (isa<ConstantDataSequential>(C) &&
1596                cast<ConstantDataSequential>(C)->isString()) {
1597       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1598       // Emit constant strings specially.
1599       unsigned NumElts = Str->getNumElements();
1600       // If this is a null-terminated string, use the denser CSTRING encoding.
1601       if (Str->isCString()) {
1602         Code = bitc::CST_CODE_CSTRING;
1603         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1604       } else {
1605         Code = bitc::CST_CODE_STRING;
1606         AbbrevToUse = String8Abbrev;
1607       }
1608       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1609       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1610       for (unsigned i = 0; i != NumElts; ++i) {
1611         unsigned char V = Str->getElementAsInteger(i);
1612         Record.push_back(V);
1613         isCStr7 &= (V & 128) == 0;
1614         if (isCStrChar6)
1615           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1616       }
1617
1618       if (isCStrChar6)
1619         AbbrevToUse = CString6Abbrev;
1620       else if (isCStr7)
1621         AbbrevToUse = CString7Abbrev;
1622     } else if (const ConstantDataSequential *CDS =
1623                   dyn_cast<ConstantDataSequential>(C)) {
1624       Code = bitc::CST_CODE_DATA;
1625       Type *EltTy = CDS->getType()->getElementType();
1626       if (isa<IntegerType>(EltTy)) {
1627         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1628           Record.push_back(CDS->getElementAsInteger(i));
1629       } else if (EltTy->isFloatTy()) {
1630         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1631           union { float F; uint32_t I; };
1632           F = CDS->getElementAsFloat(i);
1633           Record.push_back(I);
1634         }
1635       } else {
1636         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1637         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1638           union { double F; uint64_t I; };
1639           F = CDS->getElementAsDouble(i);
1640           Record.push_back(I);
1641         }
1642       }
1643     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1644                isa<ConstantVector>(C)) {
1645       Code = bitc::CST_CODE_AGGREGATE;
1646       for (const Value *Op : C->operands())
1647         Record.push_back(VE.getValueID(Op));
1648       AbbrevToUse = AggregateAbbrev;
1649     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1650       switch (CE->getOpcode()) {
1651       default:
1652         if (Instruction::isCast(CE->getOpcode())) {
1653           Code = bitc::CST_CODE_CE_CAST;
1654           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1655           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1656           Record.push_back(VE.getValueID(C->getOperand(0)));
1657           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1658         } else {
1659           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1660           Code = bitc::CST_CODE_CE_BINOP;
1661           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1662           Record.push_back(VE.getValueID(C->getOperand(0)));
1663           Record.push_back(VE.getValueID(C->getOperand(1)));
1664           uint64_t Flags = GetOptimizationFlags(CE);
1665           if (Flags != 0)
1666             Record.push_back(Flags);
1667         }
1668         break;
1669       case Instruction::GetElementPtr: {
1670         Code = bitc::CST_CODE_CE_GEP;
1671         const auto *GO = cast<GEPOperator>(C);
1672         if (GO->isInBounds())
1673           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1674         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1675         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1676           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1677           Record.push_back(VE.getValueID(C->getOperand(i)));
1678         }
1679         break;
1680       }
1681       case Instruction::Select:
1682         Code = bitc::CST_CODE_CE_SELECT;
1683         Record.push_back(VE.getValueID(C->getOperand(0)));
1684         Record.push_back(VE.getValueID(C->getOperand(1)));
1685         Record.push_back(VE.getValueID(C->getOperand(2)));
1686         break;
1687       case Instruction::ExtractElement:
1688         Code = bitc::CST_CODE_CE_EXTRACTELT;
1689         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1690         Record.push_back(VE.getValueID(C->getOperand(0)));
1691         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1692         Record.push_back(VE.getValueID(C->getOperand(1)));
1693         break;
1694       case Instruction::InsertElement:
1695         Code = bitc::CST_CODE_CE_INSERTELT;
1696         Record.push_back(VE.getValueID(C->getOperand(0)));
1697         Record.push_back(VE.getValueID(C->getOperand(1)));
1698         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1699         Record.push_back(VE.getValueID(C->getOperand(2)));
1700         break;
1701       case Instruction::ShuffleVector:
1702         // If the return type and argument types are the same, this is a
1703         // standard shufflevector instruction.  If the types are different,
1704         // then the shuffle is widening or truncating the input vectors, and
1705         // the argument type must also be encoded.
1706         if (C->getType() == C->getOperand(0)->getType()) {
1707           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1708         } else {
1709           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1710           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1711         }
1712         Record.push_back(VE.getValueID(C->getOperand(0)));
1713         Record.push_back(VE.getValueID(C->getOperand(1)));
1714         Record.push_back(VE.getValueID(C->getOperand(2)));
1715         break;
1716       case Instruction::ICmp:
1717       case Instruction::FCmp:
1718         Code = bitc::CST_CODE_CE_CMP;
1719         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1720         Record.push_back(VE.getValueID(C->getOperand(0)));
1721         Record.push_back(VE.getValueID(C->getOperand(1)));
1722         Record.push_back(CE->getPredicate());
1723         break;
1724       }
1725     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1726       Code = bitc::CST_CODE_BLOCKADDRESS;
1727       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1728       Record.push_back(VE.getValueID(BA->getFunction()));
1729       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1730     } else {
1731 #ifndef NDEBUG
1732       C->dump();
1733 #endif
1734       llvm_unreachable("Unknown constant!");
1735     }
1736     Stream.EmitRecord(Code, Record, AbbrevToUse);
1737     Record.clear();
1738   }
1739
1740   Stream.ExitBlock();
1741 }
1742
1743 static void WriteModuleConstants(const ValueEnumerator &VE,
1744                                  BitstreamWriter &Stream) {
1745   const ValueEnumerator::ValueList &Vals = VE.getValues();
1746
1747   // Find the first constant to emit, which is the first non-globalvalue value.
1748   // We know globalvalues have been emitted by WriteModuleInfo.
1749   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1750     if (!isa<GlobalValue>(Vals[i].first)) {
1751       WriteConstants(i, Vals.size(), VE, Stream, true);
1752       return;
1753     }
1754   }
1755 }
1756
1757 /// PushValueAndType - The file has to encode both the value and type id for
1758 /// many values, because we need to know what type to create for forward
1759 /// references.  However, most operands are not forward references, so this type
1760 /// field is not needed.
1761 ///
1762 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1763 /// instruction ID, then it is a forward reference, and it also includes the
1764 /// type ID.  The value ID that is written is encoded relative to the InstID.
1765 static bool PushValueAndType(const Value *V, unsigned InstID,
1766                              SmallVectorImpl<unsigned> &Vals,
1767                              ValueEnumerator &VE) {
1768   unsigned ValID = VE.getValueID(V);
1769   // Make encoding relative to the InstID.
1770   Vals.push_back(InstID - ValID);
1771   if (ValID >= InstID) {
1772     Vals.push_back(VE.getTypeID(V->getType()));
1773     return true;
1774   }
1775   return false;
1776 }
1777
1778 static void WriteOperandBundles(BitstreamWriter &Stream, ImmutableCallSite CS,
1779                                 unsigned InstID, ValueEnumerator &VE) {
1780   SmallVector<unsigned, 64> Record;
1781   LLVMContext &C = CS.getInstruction()->getContext();
1782
1783   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
1784     const auto &Bundle = CS.getOperandBundleAt(i);
1785     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
1786
1787     for (auto &Input : Bundle.Inputs)
1788       PushValueAndType(Input, InstID, Record, VE);
1789
1790     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
1791     Record.clear();
1792   }
1793 }
1794
1795 /// pushValue - Like PushValueAndType, but where the type of the value is
1796 /// omitted (perhaps it was already encoded in an earlier operand).
1797 static void pushValue(const Value *V, unsigned InstID,
1798                       SmallVectorImpl<unsigned> &Vals,
1799                       ValueEnumerator &VE) {
1800   unsigned ValID = VE.getValueID(V);
1801   Vals.push_back(InstID - ValID);
1802 }
1803
1804 static void pushValueSigned(const Value *V, unsigned InstID,
1805                             SmallVectorImpl<uint64_t> &Vals,
1806                             ValueEnumerator &VE) {
1807   unsigned ValID = VE.getValueID(V);
1808   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1809   emitSignedInt64(Vals, diff);
1810 }
1811
1812 /// WriteInstruction - Emit an instruction to the specified stream.
1813 static void WriteInstruction(const Instruction &I, unsigned InstID,
1814                              ValueEnumerator &VE, BitstreamWriter &Stream,
1815                              SmallVectorImpl<unsigned> &Vals) {
1816   unsigned Code = 0;
1817   unsigned AbbrevToUse = 0;
1818   VE.setInstructionID(&I);
1819   switch (I.getOpcode()) {
1820   default:
1821     if (Instruction::isCast(I.getOpcode())) {
1822       Code = bitc::FUNC_CODE_INST_CAST;
1823       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1824         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1825       Vals.push_back(VE.getTypeID(I.getType()));
1826       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1827     } else {
1828       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1829       Code = bitc::FUNC_CODE_INST_BINOP;
1830       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1831         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1832       pushValue(I.getOperand(1), InstID, Vals, VE);
1833       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1834       uint64_t Flags = GetOptimizationFlags(&I);
1835       if (Flags != 0) {
1836         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1837           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1838         Vals.push_back(Flags);
1839       }
1840     }
1841     break;
1842
1843   case Instruction::GetElementPtr: {
1844     Code = bitc::FUNC_CODE_INST_GEP;
1845     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1846     auto &GEPInst = cast<GetElementPtrInst>(I);
1847     Vals.push_back(GEPInst.isInBounds());
1848     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1849     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1850       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1851     break;
1852   }
1853   case Instruction::ExtractValue: {
1854     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1855     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1856     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1857     Vals.append(EVI->idx_begin(), EVI->idx_end());
1858     break;
1859   }
1860   case Instruction::InsertValue: {
1861     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1862     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1863     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1864     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1865     Vals.append(IVI->idx_begin(), IVI->idx_end());
1866     break;
1867   }
1868   case Instruction::Select:
1869     Code = bitc::FUNC_CODE_INST_VSELECT;
1870     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1871     pushValue(I.getOperand(2), InstID, Vals, VE);
1872     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1873     break;
1874   case Instruction::ExtractElement:
1875     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1876     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1877     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1878     break;
1879   case Instruction::InsertElement:
1880     Code = bitc::FUNC_CODE_INST_INSERTELT;
1881     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1882     pushValue(I.getOperand(1), InstID, Vals, VE);
1883     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1884     break;
1885   case Instruction::ShuffleVector:
1886     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1887     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1888     pushValue(I.getOperand(1), InstID, Vals, VE);
1889     pushValue(I.getOperand(2), InstID, Vals, VE);
1890     break;
1891   case Instruction::ICmp:
1892   case Instruction::FCmp: {
1893     // compare returning Int1Ty or vector of Int1Ty
1894     Code = bitc::FUNC_CODE_INST_CMP2;
1895     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1896     pushValue(I.getOperand(1), InstID, Vals, VE);
1897     Vals.push_back(cast<CmpInst>(I).getPredicate());
1898     uint64_t Flags = GetOptimizationFlags(&I);
1899     if (Flags != 0)
1900       Vals.push_back(Flags);
1901     break;
1902   }
1903
1904   case Instruction::Ret:
1905     {
1906       Code = bitc::FUNC_CODE_INST_RET;
1907       unsigned NumOperands = I.getNumOperands();
1908       if (NumOperands == 0)
1909         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1910       else if (NumOperands == 1) {
1911         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1912           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1913       } else {
1914         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1915           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1916       }
1917     }
1918     break;
1919   case Instruction::Br:
1920     {
1921       Code = bitc::FUNC_CODE_INST_BR;
1922       const BranchInst &II = cast<BranchInst>(I);
1923       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1924       if (II.isConditional()) {
1925         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1926         pushValue(II.getCondition(), InstID, Vals, VE);
1927       }
1928     }
1929     break;
1930   case Instruction::Switch:
1931     {
1932       Code = bitc::FUNC_CODE_INST_SWITCH;
1933       const SwitchInst &SI = cast<SwitchInst>(I);
1934       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1935       pushValue(SI.getCondition(), InstID, Vals, VE);
1936       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1937       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
1938         Vals.push_back(VE.getValueID(Case.getCaseValue()));
1939         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
1940       }
1941     }
1942     break;
1943   case Instruction::IndirectBr:
1944     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1945     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1946     // Encode the address operand as relative, but not the basic blocks.
1947     pushValue(I.getOperand(0), InstID, Vals, VE);
1948     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1949       Vals.push_back(VE.getValueID(I.getOperand(i)));
1950     break;
1951
1952   case Instruction::Invoke: {
1953     const InvokeInst *II = cast<InvokeInst>(&I);
1954     const Value *Callee = II->getCalledValue();
1955     FunctionType *FTy = II->getFunctionType();
1956
1957     if (II->hasOperandBundles())
1958       WriteOperandBundles(Stream, II, InstID, VE);
1959
1960     Code = bitc::FUNC_CODE_INST_INVOKE;
1961
1962     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1963     Vals.push_back(II->getCallingConv() | 1 << 13);
1964     Vals.push_back(VE.getValueID(II->getNormalDest()));
1965     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1966     Vals.push_back(VE.getTypeID(FTy));
1967     PushValueAndType(Callee, InstID, Vals, VE);
1968
1969     // Emit value #'s for the fixed parameters.
1970     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1971       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1972
1973     // Emit type/value pairs for varargs params.
1974     if (FTy->isVarArg()) {
1975       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1976            i != e; ++i)
1977         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1978     }
1979     break;
1980   }
1981   case Instruction::Resume:
1982     Code = bitc::FUNC_CODE_INST_RESUME;
1983     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1984     break;
1985   case Instruction::CleanupRet: {
1986     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
1987     const auto &CRI = cast<CleanupReturnInst>(I);
1988     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
1989     if (CRI.hasUnwindDest())
1990       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
1991     break;
1992   }
1993   case Instruction::CatchRet: {
1994     Code = bitc::FUNC_CODE_INST_CATCHRET;
1995     const auto &CRI = cast<CatchReturnInst>(I);
1996     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
1997     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
1998     break;
1999   }
2000   case Instruction::CleanupPad:
2001   case Instruction::CatchPad: {
2002     const auto &FuncletPad = cast<FuncletPadInst>(I);
2003     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2004                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2005     pushValue(FuncletPad.getParentPad(), InstID, Vals, VE);
2006
2007     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2008     Vals.push_back(NumArgOperands);
2009     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2010       PushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals, VE);
2011     break;
2012   }
2013   case Instruction::CatchSwitch: {
2014     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2015     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2016
2017     pushValue(CatchSwitch.getParentPad(), InstID, Vals, VE);
2018
2019     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2020     Vals.push_back(NumHandlers);
2021     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2022       Vals.push_back(VE.getValueID(CatchPadBB));
2023
2024     if (CatchSwitch.hasUnwindDest())
2025       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2026     break;
2027   }
2028   case Instruction::Unreachable:
2029     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2030     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2031     break;
2032
2033   case Instruction::PHI: {
2034     const PHINode &PN = cast<PHINode>(I);
2035     Code = bitc::FUNC_CODE_INST_PHI;
2036     // With the newer instruction encoding, forward references could give
2037     // negative valued IDs.  This is most common for PHIs, so we use
2038     // signed VBRs.
2039     SmallVector<uint64_t, 128> Vals64;
2040     Vals64.push_back(VE.getTypeID(PN.getType()));
2041     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2042       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
2043       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2044     }
2045     // Emit a Vals64 vector and exit.
2046     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2047     Vals64.clear();
2048     return;
2049   }
2050
2051   case Instruction::LandingPad: {
2052     const LandingPadInst &LP = cast<LandingPadInst>(I);
2053     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2054     Vals.push_back(VE.getTypeID(LP.getType()));
2055     Vals.push_back(LP.isCleanup());
2056     Vals.push_back(LP.getNumClauses());
2057     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2058       if (LP.isCatch(I))
2059         Vals.push_back(LandingPadInst::Catch);
2060       else
2061         Vals.push_back(LandingPadInst::Filter);
2062       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
2063     }
2064     break;
2065   }
2066
2067   case Instruction::Alloca: {
2068     Code = bitc::FUNC_CODE_INST_ALLOCA;
2069     const AllocaInst &AI = cast<AllocaInst>(I);
2070     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2071     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2072     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2073     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2074     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2075            "not enough bits for maximum alignment");
2076     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2077     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2078     AlignRecord |= 1 << 6;
2079     // Reserve bit 7 for SwiftError flag.
2080     // AlignRecord |= AI.isSwiftError() << 7;
2081     Vals.push_back(AlignRecord);
2082     break;
2083   }
2084
2085   case Instruction::Load:
2086     if (cast<LoadInst>(I).isAtomic()) {
2087       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2088       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2089     } else {
2090       Code = bitc::FUNC_CODE_INST_LOAD;
2091       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2092         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2093     }
2094     Vals.push_back(VE.getTypeID(I.getType()));
2095     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2096     Vals.push_back(cast<LoadInst>(I).isVolatile());
2097     if (cast<LoadInst>(I).isAtomic()) {
2098       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2099       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2100     }
2101     break;
2102   case Instruction::Store:
2103     if (cast<StoreInst>(I).isAtomic())
2104       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2105     else
2106       Code = bitc::FUNC_CODE_INST_STORE;
2107     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2108     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2109     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2110     Vals.push_back(cast<StoreInst>(I).isVolatile());
2111     if (cast<StoreInst>(I).isAtomic()) {
2112       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2113       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2114     }
2115     break;
2116   case Instruction::AtomicCmpXchg:
2117     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2118     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2119     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
2120     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2121     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2122     Vals.push_back(GetEncodedOrdering(
2123                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2124     Vals.push_back(GetEncodedSynchScope(
2125                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2126     Vals.push_back(GetEncodedOrdering(
2127                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2128     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2129     break;
2130   case Instruction::AtomicRMW:
2131     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2132     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2133     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2134     Vals.push_back(GetEncodedRMWOperation(
2135                      cast<AtomicRMWInst>(I).getOperation()));
2136     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2137     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2138     Vals.push_back(GetEncodedSynchScope(
2139                      cast<AtomicRMWInst>(I).getSynchScope()));
2140     break;
2141   case Instruction::Fence:
2142     Code = bitc::FUNC_CODE_INST_FENCE;
2143     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2144     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2145     break;
2146   case Instruction::Call: {
2147     const CallInst &CI = cast<CallInst>(I);
2148     FunctionType *FTy = CI.getFunctionType();
2149
2150     if (CI.hasOperandBundles())
2151       WriteOperandBundles(Stream, &CI, InstID, VE);
2152
2153     Code = bitc::FUNC_CODE_INST_CALL;
2154
2155     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2156
2157     unsigned Flags = GetOptimizationFlags(&I);
2158     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2159                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2160                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2161                    1 << bitc::CALL_EXPLICIT_TYPE |
2162                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2163                    unsigned(Flags != 0) << bitc::CALL_FMF);
2164     if (Flags != 0)
2165       Vals.push_back(Flags);
2166
2167     Vals.push_back(VE.getTypeID(FTy));
2168     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2169
2170     // Emit value #'s for the fixed parameters.
2171     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2172       // Check for labels (can happen with asm labels).
2173       if (FTy->getParamType(i)->isLabelTy())
2174         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2175       else
2176         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2177     }
2178
2179     // Emit type/value pairs for varargs params.
2180     if (FTy->isVarArg()) {
2181       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2182            i != e; ++i)
2183         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2184     }
2185     break;
2186   }
2187   case Instruction::VAArg:
2188     Code = bitc::FUNC_CODE_INST_VAARG;
2189     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2190     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2191     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2192     break;
2193   }
2194
2195   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2196   Vals.clear();
2197 }
2198
2199 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
2200
2201 /// Determine the encoding to use for the given string name and length.
2202 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
2203   bool isChar6 = true;
2204   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
2205     if (isChar6)
2206       isChar6 = BitCodeAbbrevOp::isChar6(*C);
2207     if ((unsigned char)*C & 128)
2208       // don't bother scanning the rest.
2209       return SE_Fixed8;
2210   }
2211   if (isChar6)
2212     return SE_Char6;
2213   else
2214     return SE_Fixed7;
2215 }
2216
2217 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2218 /// BitcodeStartBit and FunctionIndex are only passed for the module-level
2219 /// VST, where we are including a function bitcode index and need to
2220 /// backpatch the VST forward declaration record.
2221 static void WriteValueSymbolTable(
2222     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2223     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2224     uint64_t BitcodeStartBit = 0,
2225     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> *FunctionIndex =
2226         nullptr) {
2227   if (VST.empty()) {
2228     // WriteValueSymbolTableForwardDecl should have returned early as
2229     // well. Ensure this handling remains in sync by asserting that
2230     // the placeholder offset is not set.
2231     assert(VSTOffsetPlaceholder == 0);
2232     return;
2233   }
2234
2235   if (VSTOffsetPlaceholder > 0) {
2236     // Get the offset of the VST we are writing, and backpatch it into
2237     // the VST forward declaration record.
2238     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2239     // The BitcodeStartBit was the stream offset of the actual bitcode
2240     // (e.g. excluding any initial darwin header).
2241     VSTOffset -= BitcodeStartBit;
2242     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2243     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2244   }
2245
2246   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2247
2248   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2249   // records, which are not used in the per-function VSTs.
2250   unsigned FnEntry8BitAbbrev;
2251   unsigned FnEntry7BitAbbrev;
2252   unsigned FnEntry6BitAbbrev;
2253   if (VSTOffsetPlaceholder > 0) {
2254     // 8-bit fixed-width VST_FNENTRY function strings.
2255     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2256     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2257     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2261     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2262
2263     // 7-bit fixed width VST_FNENTRY function strings.
2264     Abbv = new BitCodeAbbrev();
2265     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2270     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2271
2272     // 6-bit char6 VST_FNENTRY function strings.
2273     Abbv = new BitCodeAbbrev();
2274     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2275     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2279     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2280   }
2281
2282   // FIXME: Set up the abbrev, we know how many values there are!
2283   // FIXME: We know if the type names can use 7-bit ascii.
2284   SmallVector<unsigned, 64> NameVals;
2285
2286   for (const ValueName &Name : VST) {
2287     // Figure out the encoding to use for the name.
2288     StringEncoding Bits =
2289         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2290
2291     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2292     NameVals.push_back(VE.getValueID(Name.getValue()));
2293
2294     Function *F = dyn_cast<Function>(Name.getValue());
2295     if (!F) {
2296       // If value is an alias, need to get the aliased base object to
2297       // see if it is a function.
2298       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2299       if (GA && GA->getBaseObject())
2300         F = dyn_cast<Function>(GA->getBaseObject());
2301     }
2302
2303     // VST_ENTRY:   [valueid, namechar x N]
2304     // VST_FNENTRY: [valueid, funcoffset, namechar x N]
2305     // VST_BBENTRY: [bbid, namechar x N]
2306     unsigned Code;
2307     if (isa<BasicBlock>(Name.getValue())) {
2308       Code = bitc::VST_CODE_BBENTRY;
2309       if (Bits == SE_Char6)
2310         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2311     } else if (F && !F->isDeclaration()) {
2312       // Must be the module-level VST, where we pass in the Index and
2313       // have a VSTOffsetPlaceholder. The function-level VST should not
2314       // contain any Function symbols.
2315       assert(FunctionIndex);
2316       assert(VSTOffsetPlaceholder > 0);
2317
2318       // Save the word offset of the function (from the start of the
2319       // actual bitcode written to the stream).
2320       assert(FunctionIndex->count(F) == 1);
2321       uint64_t BitcodeIndex =
2322           (*FunctionIndex)[F]->bitcodeIndex() - BitcodeStartBit;
2323       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2324       NameVals.push_back(BitcodeIndex / 32);
2325
2326       Code = bitc::VST_CODE_FNENTRY;
2327       AbbrevToUse = FnEntry8BitAbbrev;
2328       if (Bits == SE_Char6)
2329         AbbrevToUse = FnEntry6BitAbbrev;
2330       else if (Bits == SE_Fixed7)
2331         AbbrevToUse = FnEntry7BitAbbrev;
2332     } else {
2333       Code = bitc::VST_CODE_ENTRY;
2334       if (Bits == SE_Char6)
2335         AbbrevToUse = VST_ENTRY_6_ABBREV;
2336       else if (Bits == SE_Fixed7)
2337         AbbrevToUse = VST_ENTRY_7_ABBREV;
2338     }
2339
2340     for (const auto P : Name.getKey())
2341       NameVals.push_back((unsigned char)P);
2342
2343     // Emit the finished record.
2344     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2345     NameVals.clear();
2346   }
2347   Stream.ExitBlock();
2348 }
2349
2350 /// Emit function names and summary offsets for the combined index
2351 /// used by ThinLTO.
2352 static void WriteCombinedValueSymbolTable(const FunctionInfoIndex &Index,
2353                                           BitstreamWriter &Stream) {
2354   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2355
2356   // 8-bit fixed-width VST_COMBINED_FNENTRY function strings.
2357   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2358   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2362   unsigned FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2363
2364   // 7-bit fixed width VST_COMBINED_FNENTRY function strings.
2365   Abbv = new BitCodeAbbrev();
2366   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2369   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2370   unsigned FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2371
2372   // 6-bit char6 VST_COMBINED_FNENTRY function strings.
2373   Abbv = new BitCodeAbbrev();
2374   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2375   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2376   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2377   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2378   unsigned FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2379
2380   // FIXME: We know if the type names can use 7-bit ascii.
2381   SmallVector<unsigned, 64> NameVals;
2382
2383   for (const auto &FII : Index) {
2384     for (const auto &FI : FII.getValue()) {
2385       NameVals.push_back(FI->bitcodeIndex());
2386
2387       StringRef FuncName = FII.first();
2388
2389       // Figure out the encoding to use for the name.
2390       StringEncoding Bits = getStringEncoding(FuncName.data(), FuncName.size());
2391
2392       // VST_COMBINED_FNENTRY: [funcsumoffset, namechar x N]
2393       unsigned AbbrevToUse = FnEntry8BitAbbrev;
2394       if (Bits == SE_Char6)
2395         AbbrevToUse = FnEntry6BitAbbrev;
2396       else if (Bits == SE_Fixed7)
2397         AbbrevToUse = FnEntry7BitAbbrev;
2398
2399       for (const auto P : FuncName)
2400         NameVals.push_back((unsigned char)P);
2401
2402       // Emit the finished record.
2403       Stream.EmitRecord(bitc::VST_CODE_COMBINED_FNENTRY, NameVals, AbbrevToUse);
2404       NameVals.clear();
2405     }
2406   }
2407   Stream.ExitBlock();
2408 }
2409
2410 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2411                          BitstreamWriter &Stream) {
2412   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2413   unsigned Code;
2414   if (isa<BasicBlock>(Order.V))
2415     Code = bitc::USELIST_CODE_BB;
2416   else
2417     Code = bitc::USELIST_CODE_DEFAULT;
2418
2419   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2420   Record.push_back(VE.getValueID(Order.V));
2421   Stream.EmitRecord(Code, Record);
2422 }
2423
2424 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2425                               BitstreamWriter &Stream) {
2426   assert(VE.shouldPreserveUseListOrder() &&
2427          "Expected to be preserving use-list order");
2428
2429   auto hasMore = [&]() {
2430     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2431   };
2432   if (!hasMore())
2433     // Nothing to do.
2434     return;
2435
2436   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2437   while (hasMore()) {
2438     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2439     VE.UseListOrders.pop_back();
2440   }
2441   Stream.ExitBlock();
2442 }
2443
2444 /// \brief Save information for the given function into the function index.
2445 ///
2446 /// At a minimum this saves the bitcode index of the function record that
2447 /// was just written. However, if we are emitting function summary information,
2448 /// for example for ThinLTO, then a \a FunctionSummary object is created
2449 /// to hold the provided summary information.
2450 static void SaveFunctionInfo(
2451     const Function &F,
2452     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2453     unsigned NumInsts, uint64_t BitcodeIndex, bool EmitFunctionSummary) {
2454   std::unique_ptr<FunctionSummary> FuncSummary;
2455   if (EmitFunctionSummary) {
2456     FuncSummary = llvm::make_unique<FunctionSummary>(NumInsts);
2457     FuncSummary->setLocalFunction(F.hasLocalLinkage());
2458   }
2459   FunctionIndex[&F] =
2460       llvm::make_unique<FunctionInfo>(BitcodeIndex, std::move(FuncSummary));
2461 }
2462
2463 /// Emit a function body to the module stream.
2464 static void WriteFunction(
2465     const Function &F, ValueEnumerator &VE, BitstreamWriter &Stream,
2466     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2467     bool EmitFunctionSummary) {
2468   // Save the bitcode index of the start of this function block for recording
2469   // in the VST.
2470   uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
2471
2472   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2473   VE.incorporateFunction(F);
2474
2475   SmallVector<unsigned, 64> Vals;
2476
2477   // Emit the number of basic blocks, so the reader can create them ahead of
2478   // time.
2479   Vals.push_back(VE.getBasicBlocks().size());
2480   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2481   Vals.clear();
2482
2483   // If there are function-local constants, emit them now.
2484   unsigned CstStart, CstEnd;
2485   VE.getFunctionConstantRange(CstStart, CstEnd);
2486   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2487
2488   // If there is function-local metadata, emit it now.
2489   WriteFunctionLocalMetadata(F, VE, Stream);
2490
2491   // Keep a running idea of what the instruction ID is.
2492   unsigned InstID = CstEnd;
2493
2494   bool NeedsMetadataAttachment = F.hasMetadata();
2495
2496   DILocation *LastDL = nullptr;
2497   unsigned NumInsts = 0;
2498
2499   // Finally, emit all the instructions, in order.
2500   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2501     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2502          I != E; ++I) {
2503       WriteInstruction(*I, InstID, VE, Stream, Vals);
2504
2505       if (!isa<DbgInfoIntrinsic>(I))
2506         ++NumInsts;
2507
2508       if (!I->getType()->isVoidTy())
2509         ++InstID;
2510
2511       // If the instruction has metadata, write a metadata attachment later.
2512       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2513
2514       // If the instruction has a debug location, emit it.
2515       DILocation *DL = I->getDebugLoc();
2516       if (!DL)
2517         continue;
2518
2519       if (DL == LastDL) {
2520         // Just repeat the same debug loc as last time.
2521         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2522         continue;
2523       }
2524
2525       Vals.push_back(DL->getLine());
2526       Vals.push_back(DL->getColumn());
2527       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2528       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2529       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2530       Vals.clear();
2531
2532       LastDL = DL;
2533     }
2534
2535   // Emit names for all the instructions etc.
2536   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2537
2538   if (NeedsMetadataAttachment)
2539     WriteMetadataAttachment(F, VE, Stream);
2540   if (VE.shouldPreserveUseListOrder())
2541     WriteUseListBlock(&F, VE, Stream);
2542   VE.purgeFunction();
2543   Stream.ExitBlock();
2544
2545   SaveFunctionInfo(F, FunctionIndex, NumInsts, BitcodeIndex,
2546                    EmitFunctionSummary);
2547 }
2548
2549 // Emit blockinfo, which defines the standard abbreviations etc.
2550 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2551   // We only want to emit block info records for blocks that have multiple
2552   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2553   // Other blocks can define their abbrevs inline.
2554   Stream.EnterBlockInfoBlock(2);
2555
2556   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2557     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2561     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2562     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2563                                    Abbv) != VST_ENTRY_8_ABBREV)
2564       llvm_unreachable("Unexpected abbrev ordering!");
2565   }
2566
2567   { // 7-bit fixed width VST_ENTRY strings.
2568     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2569     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2572     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2573     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2574                                    Abbv) != VST_ENTRY_7_ABBREV)
2575       llvm_unreachable("Unexpected abbrev ordering!");
2576   }
2577   { // 6-bit char6 VST_ENTRY strings.
2578     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2579     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2583     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2584                                    Abbv) != VST_ENTRY_6_ABBREV)
2585       llvm_unreachable("Unexpected abbrev ordering!");
2586   }
2587   { // 6-bit char6 VST_BBENTRY strings.
2588     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2589     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2593     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2594                                    Abbv) != VST_BBENTRY_6_ABBREV)
2595       llvm_unreachable("Unexpected abbrev ordering!");
2596   }
2597
2598
2599
2600   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2601     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2602     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2604                               VE.computeBitsRequiredForTypeIndicies()));
2605     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2606                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2607       llvm_unreachable("Unexpected abbrev ordering!");
2608   }
2609
2610   { // INTEGER abbrev for CONSTANTS_BLOCK.
2611     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2612     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2614     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2615                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2616       llvm_unreachable("Unexpected abbrev ordering!");
2617   }
2618
2619   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2620     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2621     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2623     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2624                               VE.computeBitsRequiredForTypeIndicies()));
2625     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2626
2627     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2628                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2629       llvm_unreachable("Unexpected abbrev ordering!");
2630   }
2631   { // NULL abbrev for CONSTANTS_BLOCK.
2632     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2633     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2634     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2635                                    Abbv) != CONSTANTS_NULL_Abbrev)
2636       llvm_unreachable("Unexpected abbrev ordering!");
2637   }
2638
2639   // FIXME: This should only use space for first class types!
2640
2641   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2642     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2643     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2645     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2646                               VE.computeBitsRequiredForTypeIndicies()));
2647     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2649     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2650                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2651       llvm_unreachable("Unexpected abbrev ordering!");
2652   }
2653   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2654     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2655     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2658     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2659     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2660                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2661       llvm_unreachable("Unexpected abbrev ordering!");
2662   }
2663   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2664     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2665     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2666     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2670     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2671                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2672       llvm_unreachable("Unexpected abbrev ordering!");
2673   }
2674   { // INST_CAST abbrev for FUNCTION_BLOCK.
2675     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2676     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2679                               VE.computeBitsRequiredForTypeIndicies()));
2680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2681     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2682                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2683       llvm_unreachable("Unexpected abbrev ordering!");
2684   }
2685
2686   { // INST_RET abbrev for FUNCTION_BLOCK.
2687     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2688     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2689     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2690                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2691       llvm_unreachable("Unexpected abbrev ordering!");
2692   }
2693   { // INST_RET abbrev for FUNCTION_BLOCK.
2694     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2695     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2696     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2697     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2698                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2699       llvm_unreachable("Unexpected abbrev ordering!");
2700   }
2701   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2702     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2703     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2704     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2705                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2706       llvm_unreachable("Unexpected abbrev ordering!");
2707   }
2708   {
2709     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2710     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2711     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2712     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2713                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2714     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2715     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2716     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2717         FUNCTION_INST_GEP_ABBREV)
2718       llvm_unreachable("Unexpected abbrev ordering!");
2719   }
2720
2721   Stream.ExitBlock();
2722 }
2723
2724 /// Write the module path strings, currently only used when generating
2725 /// a combined index file.
2726 static void WriteModStrings(const FunctionInfoIndex &I,
2727                             BitstreamWriter &Stream) {
2728   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2729
2730   // TODO: See which abbrev sizes we actually need to emit
2731
2732   // 8-bit fixed-width MST_ENTRY strings.
2733   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2734   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2735   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2736   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2737   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2738   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2739
2740   // 7-bit fixed width MST_ENTRY strings.
2741   Abbv = new BitCodeAbbrev();
2742   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2743   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2744   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2745   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2746   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2747
2748   // 6-bit char6 MST_ENTRY strings.
2749   Abbv = new BitCodeAbbrev();
2750   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2751   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2754   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2755
2756   SmallVector<unsigned, 64> NameVals;
2757   for (const StringMapEntry<uint64_t> &MPSE : I.modPathStringEntries()) {
2758     StringEncoding Bits =
2759         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2760     unsigned AbbrevToUse = Abbrev8Bit;
2761     if (Bits == SE_Char6)
2762       AbbrevToUse = Abbrev6Bit;
2763     else if (Bits == SE_Fixed7)
2764       AbbrevToUse = Abbrev7Bit;
2765
2766     NameVals.push_back(MPSE.getValue());
2767
2768     for (const auto P : MPSE.getKey())
2769       NameVals.push_back((unsigned char)P);
2770
2771     // Emit the finished record.
2772     Stream.EmitRecord(bitc::MST_CODE_ENTRY, NameVals, AbbrevToUse);
2773     NameVals.clear();
2774   }
2775   Stream.ExitBlock();
2776 }
2777
2778 // Helper to emit a single function summary record.
2779 static void WritePerModuleFunctionSummaryRecord(
2780     SmallVector<unsigned, 64> &NameVals, FunctionSummary *FS, unsigned ValueID,
2781     unsigned FSAbbrev, BitstreamWriter &Stream) {
2782   assert(FS);
2783   NameVals.push_back(ValueID);
2784   NameVals.push_back(FS->isLocalFunction());
2785   NameVals.push_back(FS->instCount());
2786
2787   // Emit the finished record.
2788   Stream.EmitRecord(bitc::FS_CODE_PERMODULE_ENTRY, NameVals, FSAbbrev);
2789   NameVals.clear();
2790 }
2791
2792 /// Emit the per-module function summary section alongside the rest of
2793 /// the module's bitcode.
2794 static void WritePerModuleFunctionSummary(
2795     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2796     const Module *M, const ValueEnumerator &VE, BitstreamWriter &Stream) {
2797   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2798
2799   // Abbrev for FS_CODE_PERMODULE_ENTRY.
2800   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2801   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_PERMODULE_ENTRY));
2802   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
2803   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // islocal
2804   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2805   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2806
2807   SmallVector<unsigned, 64> NameVals;
2808   for (auto &I : FunctionIndex) {
2809     // Skip anonymous functions. We will emit a function summary for
2810     // any aliases below.
2811     if (!I.first->hasName())
2812       continue;
2813
2814     WritePerModuleFunctionSummaryRecord(
2815         NameVals, I.second->functionSummary(),
2816         VE.getValueID(M->getValueSymbolTable().lookup(I.first->getName())),
2817         FSAbbrev, Stream);
2818   }
2819
2820   for (const GlobalAlias &A : M->aliases()) {
2821     if (!A.getBaseObject())
2822       continue;
2823     const Function *F = dyn_cast<Function>(A.getBaseObject());
2824     if (!F || F->isDeclaration())
2825       continue;
2826
2827     assert(FunctionIndex.count(F) == 1);
2828     WritePerModuleFunctionSummaryRecord(
2829         NameVals, FunctionIndex[F]->functionSummary(),
2830         VE.getValueID(M->getValueSymbolTable().lookup(A.getName())), FSAbbrev,
2831         Stream);
2832   }
2833
2834   Stream.ExitBlock();
2835 }
2836
2837 /// Emit the combined function summary section into the combined index
2838 /// file.
2839 static void WriteCombinedFunctionSummary(const FunctionInfoIndex &I,
2840                                          BitstreamWriter &Stream) {
2841   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2842
2843   // Abbrev for FS_CODE_COMBINED_ENTRY.
2844   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2845   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_COMBINED_ENTRY));
2846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // modid
2847   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // instcount
2848   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2849
2850   SmallVector<unsigned, 64> NameVals;
2851   for (const auto &FII : I) {
2852     for (auto &FI : FII.getValue()) {
2853       FunctionSummary *FS = FI->functionSummary();
2854       assert(FS);
2855
2856       NameVals.push_back(I.getModuleId(FS->modulePath()));
2857       NameVals.push_back(FS->instCount());
2858
2859       // Record the starting offset of this summary entry for use
2860       // in the VST entry. Add the current code size since the
2861       // reader will invoke readRecord after the abbrev id read.
2862       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
2863
2864       // Emit the finished record.
2865       Stream.EmitRecord(bitc::FS_CODE_COMBINED_ENTRY, NameVals, FSAbbrev);
2866       NameVals.clear();
2867     }
2868   }
2869
2870   Stream.ExitBlock();
2871 }
2872
2873 // Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
2874 // current llvm version, and a record for the epoch number.
2875 static void WriteIdentificationBlock(const Module *M, BitstreamWriter &Stream) {
2876   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
2877
2878   // Write the "user readable" string identifying the bitcode producer
2879   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2880   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
2881   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2883   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
2884   WriteStringRecord(bitc::IDENTIFICATION_CODE_STRING,
2885                     "LLVM" LLVM_VERSION_STRING, StringAbbrev, Stream);
2886
2887   // Write the epoch version
2888   Abbv = new BitCodeAbbrev();
2889   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
2890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2891   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
2892   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
2893   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
2894   Stream.ExitBlock();
2895 }
2896
2897 /// WriteModule - Emit the specified module to the bitstream.
2898 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2899                         bool ShouldPreserveUseListOrder,
2900                         uint64_t BitcodeStartBit, bool EmitFunctionSummary) {
2901   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2902
2903   SmallVector<unsigned, 1> Vals;
2904   unsigned CurVersion = 1;
2905   Vals.push_back(CurVersion);
2906   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2907
2908   // Analyze the module, enumerating globals, functions, etc.
2909   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2910
2911   // Emit blockinfo, which defines the standard abbreviations etc.
2912   WriteBlockInfo(VE, Stream);
2913
2914   // Emit information about attribute groups.
2915   WriteAttributeGroupTable(VE, Stream);
2916
2917   // Emit information about parameter attributes.
2918   WriteAttributeTable(VE, Stream);
2919
2920   // Emit information describing all of the types in the module.
2921   WriteTypeTable(VE, Stream);
2922
2923   writeComdats(VE, Stream);
2924
2925   // Emit top-level description of module, including target triple, inline asm,
2926   // descriptors for global variables, and function prototype info.
2927   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
2928
2929   // Emit constants.
2930   WriteModuleConstants(VE, Stream);
2931
2932   // Emit metadata.
2933   WriteModuleMetadata(M, VE, Stream);
2934
2935   // Emit metadata.
2936   WriteModuleMetadataStore(M, Stream);
2937
2938   // Emit module-level use-lists.
2939   if (VE.shouldPreserveUseListOrder())
2940     WriteUseListBlock(nullptr, VE, Stream);
2941
2942   WriteOperandBundleTags(M, Stream);
2943
2944   // Emit function bodies.
2945   DenseMap<const Function *, std::unique_ptr<FunctionInfo>> FunctionIndex;
2946   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2947     if (!F->isDeclaration())
2948       WriteFunction(*F, VE, Stream, FunctionIndex, EmitFunctionSummary);
2949
2950   // Need to write after the above call to WriteFunction which populates
2951   // the summary information in the index.
2952   if (EmitFunctionSummary)
2953     WritePerModuleFunctionSummary(FunctionIndex, M, VE, Stream);
2954
2955   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
2956                         VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
2957
2958   Stream.ExitBlock();
2959 }
2960
2961 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2962 /// header and trailer to make it compatible with the system archiver.  To do
2963 /// this we emit the following header, and then emit a trailer that pads the
2964 /// file out to be a multiple of 16 bytes.
2965 ///
2966 /// struct bc_header {
2967 ///   uint32_t Magic;         // 0x0B17C0DE
2968 ///   uint32_t Version;       // Version, currently always 0.
2969 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2970 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2971 ///   uint32_t CPUType;       // CPU specifier.
2972 ///   ... potentially more later ...
2973 /// };
2974 enum {
2975   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2976   DarwinBCHeaderSize = 5*4
2977 };
2978
2979 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2980                                uint32_t &Position) {
2981   support::endian::write32le(&Buffer[Position], Value);
2982   Position += 4;
2983 }
2984
2985 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2986                                          const Triple &TT) {
2987   unsigned CPUType = ~0U;
2988
2989   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2990   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2991   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2992   // specific constants here because they are implicitly part of the Darwin ABI.
2993   enum {
2994     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2995     DARWIN_CPU_TYPE_X86        = 7,
2996     DARWIN_CPU_TYPE_ARM        = 12,
2997     DARWIN_CPU_TYPE_POWERPC    = 18
2998   };
2999
3000   Triple::ArchType Arch = TT.getArch();
3001   if (Arch == Triple::x86_64)
3002     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3003   else if (Arch == Triple::x86)
3004     CPUType = DARWIN_CPU_TYPE_X86;
3005   else if (Arch == Triple::ppc)
3006     CPUType = DARWIN_CPU_TYPE_POWERPC;
3007   else if (Arch == Triple::ppc64)
3008     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3009   else if (Arch == Triple::arm || Arch == Triple::thumb)
3010     CPUType = DARWIN_CPU_TYPE_ARM;
3011
3012   // Traditional Bitcode starts after header.
3013   assert(Buffer.size() >= DarwinBCHeaderSize &&
3014          "Expected header size to be reserved");
3015   unsigned BCOffset = DarwinBCHeaderSize;
3016   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
3017
3018   // Write the magic and version.
3019   unsigned Position = 0;
3020   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
3021   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
3022   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
3023   WriteInt32ToBuffer(BCSize     , Buffer, Position);
3024   WriteInt32ToBuffer(CPUType    , Buffer, Position);
3025
3026   // If the file is not a multiple of 16 bytes, insert dummy padding.
3027   while (Buffer.size() & 15)
3028     Buffer.push_back(0);
3029 }
3030
3031 /// Helper to write the header common to all bitcode files.
3032 static void WriteBitcodeHeader(BitstreamWriter &Stream) {
3033   // Emit the file header.
3034   Stream.Emit((unsigned)'B', 8);
3035   Stream.Emit((unsigned)'C', 8);
3036   Stream.Emit(0x0, 4);
3037   Stream.Emit(0xC, 4);
3038   Stream.Emit(0xE, 4);
3039   Stream.Emit(0xD, 4);
3040 }
3041
3042 /// WriteBitcodeToFile - Write the specified module to the specified output
3043 /// stream.
3044 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3045                               bool ShouldPreserveUseListOrder,
3046                               bool EmitFunctionSummary) {
3047   SmallVector<char, 0> Buffer;
3048   Buffer.reserve(256*1024);
3049
3050   // If this is darwin or another generic macho target, reserve space for the
3051   // header.
3052   Triple TT(M->getTargetTriple());
3053   if (TT.isOSDarwin())
3054     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
3055
3056   // Emit the module into the buffer.
3057   {
3058     BitstreamWriter Stream(Buffer);
3059     // Save the start bit of the actual bitcode, in case there is space
3060     // saved at the start for the darwin header above. The reader stream
3061     // will start at the bitcode, and we need the offset of the VST
3062     // to line up.
3063     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
3064
3065     // Emit the file header.
3066     WriteBitcodeHeader(Stream);
3067
3068     WriteIdentificationBlock(M, Stream);
3069
3070     // Emit the module.
3071     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit,
3072                 EmitFunctionSummary);
3073   }
3074
3075   if (TT.isOSDarwin())
3076     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
3077
3078   // Write the generated bitstream to "Out".
3079   Out.write((char*)&Buffer.front(), Buffer.size());
3080 }
3081
3082 // Write the specified function summary index to the given raw output stream,
3083 // where it will be written in a new bitcode block. This is used when
3084 // writing the combined index file for ThinLTO.
3085 void llvm::WriteFunctionSummaryToFile(const FunctionInfoIndex &Index,
3086                                       raw_ostream &Out) {
3087   SmallVector<char, 0> Buffer;
3088   Buffer.reserve(256 * 1024);
3089
3090   BitstreamWriter Stream(Buffer);
3091
3092   // Emit the bitcode header.
3093   WriteBitcodeHeader(Stream);
3094
3095   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3096
3097   SmallVector<unsigned, 1> Vals;
3098   unsigned CurVersion = 1;
3099   Vals.push_back(CurVersion);
3100   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3101
3102   // Write the module paths in the combined index.
3103   WriteModStrings(Index, Stream);
3104
3105   // Write the function summary combined index records.
3106   WriteCombinedFunctionSummary(Index, Stream);
3107
3108   // Need a special VST writer for the combined index (we don't have a
3109   // real VST and real values when this is invoked).
3110   WriteCombinedValueSymbolTable(Index, Stream);
3111
3112   Stream.ExitBlock();
3113
3114   Out.write((char *)&Buffer.front(), Buffer.size());
3115 }