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   uint64_t VSTOffsetPlaceholder =
 780       WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
 781   return VSTOffsetPlaceholder;
 782 }
 783
 784 static uint64_t GetOptimizationFlags(const Value *V) {
 785   uint64_t Flags = 0;
 786
 787   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 788     if (OBO->hasNoSignedWrap())
 789       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 790     if (OBO->hasNoUnsignedWrap())
 791       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 792   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 793     if (PEO->isExact())
 794       Flags |= 1 << bitc::PEO_EXACT;
 795   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 796     if (FPMO->hasUnsafeAlgebra())
 797       Flags |= FastMathFlags::UnsafeAlgebra;
 798     if (FPMO->hasNoNaNs())
 799       Flags |= FastMathFlags::NoNaNs;
 800     if (FPMO->hasNoInfs())
 801       Flags |= FastMathFlags::NoInfs;
 802     if (FPMO->hasNoSignedZeros())
 803       Flags |= FastMathFlags::NoSignedZeros;
 804     if (FPMO->hasAllowReciprocal())
 805       Flags |= FastMathFlags::AllowReciprocal;
 806   }
 807
 808   return Flags;
 809 }
 810
 811 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 812                                  const ValueEnumerator &VE,
 813                                  BitstreamWriter &Stream,
 814                                  SmallVectorImpl<uint64_t> &Record) {
 815   // Mimic an MDNode with a value as one operand.
 816   Value *V = MD->getValue();
 817   Record.push_back(VE.getTypeID(V->getType()));
 818   Record.push_back(VE.getValueID(V));
 819   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 820   Record.clear();
 821 }
 822
 823 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 824                          BitstreamWriter &Stream,
 825                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 826   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 827     Metadata *MD = N->getOperand(i);
 828     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 829            "Unexpected function-local metadata");
 830     Record.push_back(VE.getMetadataOrNullID(MD));
 831   }
 832   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 833                                     : bitc::METADATA_NODE,
 834                     Record, Abbrev);
 835   Record.clear();
 836 }
 837
 838 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 839                             BitstreamWriter &Stream,
 840                             SmallVectorImpl<uint64_t> &Record,
 841                             unsigned Abbrev) {
 842   Record.push_back(N->isDistinct());
 843   Record.push_back(N->getLine());
 844   Record.push_back(N->getColumn());
 845   Record.push_back(VE.getMetadataID(N->getScope()));
 846   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 847
 848   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 849   Record.clear();
 850 }
 851
 852 static void WriteGenericDINode(const GenericDINode *N,
 853                                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->getTag());
 859   Record.push_back(0); // Per-tag version field; unused for now.
 860
 861   for (auto &I : N->operands())
 862     Record.push_back(VE.getMetadataOrNullID(I));
 863
 864   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 865   Record.clear();
 866 }
 867
 868 static uint64_t rotateSign(int64_t I) {
 869   uint64_t U = I;
 870   return I < 0 ? ~(U << 1) : U << 1;
 871 }
 872
 873 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 874                             BitstreamWriter &Stream,
 875                             SmallVectorImpl<uint64_t> &Record,
 876                             unsigned Abbrev) {
 877   Record.push_back(N->isDistinct());
 878   Record.push_back(N->getCount());
 879   Record.push_back(rotateSign(N->getLowerBound()));
 880
 881   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 882   Record.clear();
 883 }
 884
 885 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 886                               BitstreamWriter &Stream,
 887                               SmallVectorImpl<uint64_t> &Record,
 888                               unsigned Abbrev) {
 889   Record.push_back(N->isDistinct());
 890   Record.push_back(rotateSign(N->getValue()));
 891   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 892
 893   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 894   Record.clear();
 895 }
 896
 897 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 898                              BitstreamWriter &Stream,
 899                              SmallVectorImpl<uint64_t> &Record,
 900                              unsigned Abbrev) {
 901   Record.push_back(N->isDistinct());
 902   Record.push_back(N->getTag());
 903   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 904   Record.push_back(N->getSizeInBits());
 905   Record.push_back(N->getAlignInBits());
 906   Record.push_back(N->getEncoding());
 907
 908   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 909   Record.clear();
 910 }
 911
 912 static void WriteDIDerivedType(const DIDerivedType *N,
 913                                const ValueEnumerator &VE,
 914                                BitstreamWriter &Stream,
 915                                SmallVectorImpl<uint64_t> &Record,
 916                                unsigned Abbrev) {
 917   Record.push_back(N->isDistinct());
 918   Record.push_back(N->getTag());
 919   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 920   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 921   Record.push_back(N->getLine());
 922   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 923   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 924   Record.push_back(N->getSizeInBits());
 925   Record.push_back(N->getAlignInBits());
 926   Record.push_back(N->getOffsetInBits());
 927   Record.push_back(N->getFlags());
 928   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 929
 930   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 931   Record.clear();
 932 }
 933
 934 static void WriteDICompositeType(const DICompositeType *N,
 935                                  const ValueEnumerator &VE,
 936                                  BitstreamWriter &Stream,
 937                                  SmallVectorImpl<uint64_t> &Record,
 938                                  unsigned Abbrev) {
 939   Record.push_back(N->isDistinct());
 940   Record.push_back(N->getTag());
 941   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 942   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 943   Record.push_back(N->getLine());
 944   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 945   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 946   Record.push_back(N->getSizeInBits());
 947   Record.push_back(N->getAlignInBits());
 948   Record.push_back(N->getOffsetInBits());
 949   Record.push_back(N->getFlags());
 950   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 951   Record.push_back(N->getRuntimeLang());
 952   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 953   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 954   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 955
 956   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 957   Record.clear();
 958 }
 959
 960 static void WriteDISubroutineType(const DISubroutineType *N,
 961                                   const ValueEnumerator &VE,
 962                                   BitstreamWriter &Stream,
 963                                   SmallVectorImpl<uint64_t> &Record,
 964                                   unsigned Abbrev) {
 965   Record.push_back(N->isDistinct());
 966   Record.push_back(N->getFlags());
 967   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 968
 969   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 970   Record.clear();
 971 }
 972
 973 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 974                         BitstreamWriter &Stream,
 975                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 976   Record.push_back(N->isDistinct());
 977   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 978   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 979
 980   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 981   Record.clear();
 982 }
 983
 984 static void WriteDICompileUnit(const DICompileUnit *N,
 985                                const ValueEnumerator &VE,
 986                                BitstreamWriter &Stream,
 987                                SmallVectorImpl<uint64_t> &Record,
 988                                unsigned Abbrev) {
 989   assert(N->isDistinct() && "Expected distinct compile units");
 990   Record.push_back(/* IsDistinct */ true);
 991   Record.push_back(N->getSourceLanguage());
 992   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 993   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 994   Record.push_back(N->isOptimized());
 995   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 996   Record.push_back(N->getRuntimeVersion());
 997   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 998   Record.push_back(N->getEmissionKind());
 999   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1000   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1001   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
1002   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1003   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1004   Record.push_back(N->getDWOId());
1005
1006   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1007   Record.clear();
1008 }
1009
1010 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1011                               BitstreamWriter &Stream,
1012                               SmallVectorImpl<uint64_t> &Record,
1013                               unsigned Abbrev) {
1014   Record.push_back(N->isDistinct());
1015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1016   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1017   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1018   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1019   Record.push_back(N->getLine());
1020   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1021   Record.push_back(N->isLocalToUnit());
1022   Record.push_back(N->isDefinition());
1023   Record.push_back(N->getScopeLine());
1024   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1025   Record.push_back(N->getVirtuality());
1026   Record.push_back(N->getVirtualIndex());
1027   Record.push_back(N->getFlags());
1028   Record.push_back(N->isOptimized());
1029   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1030   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1031   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1032
1033   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1034   Record.clear();
1035 }
1036
1037 static void WriteDILexicalBlock(const DILexicalBlock *N,
1038                                 const ValueEnumerator &VE,
1039                                 BitstreamWriter &Stream,
1040                                 SmallVectorImpl<uint64_t> &Record,
1041                                 unsigned Abbrev) {
1042   Record.push_back(N->isDistinct());
1043   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1044   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1045   Record.push_back(N->getLine());
1046   Record.push_back(N->getColumn());
1047
1048   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1049   Record.clear();
1050 }
1051
1052 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1053                                     const ValueEnumerator &VE,
1054                                     BitstreamWriter &Stream,
1055                                     SmallVectorImpl<uint64_t> &Record,
1056                                     unsigned Abbrev) {
1057   Record.push_back(N->isDistinct());
1058   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1059   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1060   Record.push_back(N->getDiscriminator());
1061
1062   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1063   Record.clear();
1064 }
1065
1066 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1067                              BitstreamWriter &Stream,
1068                              SmallVectorImpl<uint64_t> &Record,
1069                              unsigned Abbrev) {
1070   Record.push_back(N->isDistinct());
1071   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1072   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1073   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1074   Record.push_back(N->getLine());
1075
1076   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1077   Record.clear();
1078 }
1079
1080 static void WriteDIModule(const DIModule *N, const ValueEnumerator &VE,
1081                           BitstreamWriter &Stream,
1082                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1083   Record.push_back(N->isDistinct());
1084   for (auto &I : N->operands())
1085     Record.push_back(VE.getMetadataOrNullID(I));
1086
1087   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1088   Record.clear();
1089 }
1090
1091 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1092                                          const ValueEnumerator &VE,
1093                                          BitstreamWriter &Stream,
1094                                          SmallVectorImpl<uint64_t> &Record,
1095                                          unsigned Abbrev) {
1096   Record.push_back(N->isDistinct());
1097   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1098   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1099
1100   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1101   Record.clear();
1102 }
1103
1104 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1105                                           const ValueEnumerator &VE,
1106                                           BitstreamWriter &Stream,
1107                                           SmallVectorImpl<uint64_t> &Record,
1108                                           unsigned Abbrev) {
1109   Record.push_back(N->isDistinct());
1110   Record.push_back(N->getTag());
1111   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1112   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1113   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1114
1115   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1116   Record.clear();
1117 }
1118
1119 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1120                                   const ValueEnumerator &VE,
1121                                   BitstreamWriter &Stream,
1122                                   SmallVectorImpl<uint64_t> &Record,
1123                                   unsigned Abbrev) {
1124   Record.push_back(N->isDistinct());
1125   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1126   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1127   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1128   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1129   Record.push_back(N->getLine());
1130   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1131   Record.push_back(N->isLocalToUnit());
1132   Record.push_back(N->isDefinition());
1133   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1134   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1135
1136   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1137   Record.clear();
1138 }
1139
1140 static void WriteDILocalVariable(const DILocalVariable *N,
1141                                  const ValueEnumerator &VE,
1142                                  BitstreamWriter &Stream,
1143                                  SmallVectorImpl<uint64_t> &Record,
1144                                  unsigned Abbrev) {
1145   Record.push_back(N->isDistinct());
1146   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1147   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1148   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1149   Record.push_back(N->getLine());
1150   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1151   Record.push_back(N->getArg());
1152   Record.push_back(N->getFlags());
1153
1154   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1155   Record.clear();
1156 }
1157
1158 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1159                               BitstreamWriter &Stream,
1160                               SmallVectorImpl<uint64_t> &Record,
1161                               unsigned Abbrev) {
1162   Record.reserve(N->getElements().size() + 1);
1163
1164   Record.push_back(N->isDistinct());
1165   Record.append(N->elements_begin(), N->elements_end());
1166
1167   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1168   Record.clear();
1169 }
1170
1171 static void WriteDIObjCProperty(const DIObjCProperty *N,
1172                                 const ValueEnumerator &VE,
1173                                 BitstreamWriter &Stream,
1174                                 SmallVectorImpl<uint64_t> &Record,
1175                                 unsigned Abbrev) {
1176   Record.push_back(N->isDistinct());
1177   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1178   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1179   Record.push_back(N->getLine());
1180   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1181   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1182   Record.push_back(N->getAttributes());
1183   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1184
1185   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1186   Record.clear();
1187 }
1188
1189 static void WriteDIImportedEntity(const DIImportedEntity *N,
1190                                   const ValueEnumerator &VE,
1191                                   BitstreamWriter &Stream,
1192                                   SmallVectorImpl<uint64_t> &Record,
1193                                   unsigned Abbrev) {
1194   Record.push_back(N->isDistinct());
1195   Record.push_back(N->getTag());
1196   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1197   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1198   Record.push_back(N->getLine());
1199   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1200
1201   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1202   Record.clear();
1203 }
1204
1205 static void WriteModuleMetadata(const Module *M,
1206                                 const ValueEnumerator &VE,
1207                                 BitstreamWriter &Stream) {
1208   const auto &MDs = VE.getMDs();
1209   if (MDs.empty() && M->named_metadata_empty())
1210     return;
1211
1212   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1213
1214   unsigned MDSAbbrev = 0;
1215   if (VE.hasMDString()) {
1216     // Abbrev for METADATA_STRING.
1217     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1218     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1219     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1221     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1222   }
1223
1224   // Initialize MDNode abbreviations.
1225 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1226 #include "llvm/IR/Metadata.def"
1227
1228   if (VE.hasDILocation()) {
1229     // Abbrev for METADATA_LOCATION.
1230     //
1231     // Assume the column is usually under 128, and always output the inlined-at
1232     // location (it's never more expensive than building an array size 1).
1233     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1234     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1240     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1241   }
1242
1243   if (VE.hasGenericDINode()) {
1244     // Abbrev for METADATA_GENERIC_DEBUG.
1245     //
1246     // Assume the column is usually under 128, and always output the inlined-at
1247     // location (it's never more expensive than building an array size 1).
1248     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1249     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1256     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1257   }
1258
1259   unsigned NameAbbrev = 0;
1260   if (!M->named_metadata_empty()) {
1261     // Abbrev for METADATA_NAME.
1262     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1263     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1266     NameAbbrev = Stream.EmitAbbrev(Abbv);
1267   }
1268
1269   SmallVector<uint64_t, 64> Record;
1270   for (const Metadata *MD : MDs) {
1271     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1272       assert(N->isResolved() && "Expected forward references to be resolved");
1273
1274       switch (N->getMetadataID()) {
1275       default:
1276         llvm_unreachable("Invalid MDNode subclass");
1277 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1278   case Metadata::CLASS##Kind:                                                  \
1279     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1280     continue;
1281 #include "llvm/IR/Metadata.def"
1282       }
1283     }
1284     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1285       WriteValueAsMetadata(MDC, VE, Stream, Record);
1286       continue;
1287     }
1288     const MDString *MDS = cast<MDString>(MD);
1289     // Code: [strchar x N]
1290     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1291
1292     // Emit the finished record.
1293     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1294     Record.clear();
1295   }
1296
1297   // Write named metadata.
1298   for (const NamedMDNode &NMD : M->named_metadata()) {
1299     // Write name.
1300     StringRef Str = NMD.getName();
1301     Record.append(Str.bytes_begin(), Str.bytes_end());
1302     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1303     Record.clear();
1304
1305     // Write named metadata operands.
1306     for (const MDNode *N : NMD.operands())
1307       Record.push_back(VE.getMetadataID(N));
1308     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1309     Record.clear();
1310   }
1311
1312   Stream.ExitBlock();
1313 }
1314
1315 static void WriteFunctionLocalMetadata(const Function &F,
1316                                        const ValueEnumerator &VE,
1317                                        BitstreamWriter &Stream) {
1318   bool StartedMetadataBlock = false;
1319   SmallVector<uint64_t, 64> Record;
1320   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1321       VE.getFunctionLocalMDs();
1322   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1323     assert(MDs[i] && "Expected valid function-local metadata");
1324     if (!StartedMetadataBlock) {
1325       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1326       StartedMetadataBlock = true;
1327     }
1328     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1329   }
1330
1331   if (StartedMetadataBlock)
1332     Stream.ExitBlock();
1333 }
1334
1335 static void WriteMetadataAttachment(const Function &F,
1336                                     const ValueEnumerator &VE,
1337                                     BitstreamWriter &Stream) {
1338   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1339
1340   SmallVector<uint64_t, 64> Record;
1341
1342   // Write metadata attachments
1343   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1344   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1345   F.getAllMetadata(MDs);
1346   if (!MDs.empty()) {
1347     for (const auto &I : MDs) {
1348       Record.push_back(I.first);
1349       Record.push_back(VE.getMetadataID(I.second));
1350     }
1351     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1352     Record.clear();
1353   }
1354
1355   for (const BasicBlock &BB : F)
1356     for (const Instruction &I : BB) {
1357       MDs.clear();
1358       I.getAllMetadataOtherThanDebugLoc(MDs);
1359
1360       // If no metadata, ignore instruction.
1361       if (MDs.empty()) continue;
1362
1363       Record.push_back(VE.getInstructionID(&I));
1364
1365       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1366         Record.push_back(MDs[i].first);
1367         Record.push_back(VE.getMetadataID(MDs[i].second));
1368       }
1369       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1370       Record.clear();
1371     }
1372
1373   Stream.ExitBlock();
1374 }
1375
1376 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1377   SmallVector<uint64_t, 64> Record;
1378
1379   // Write metadata kinds
1380   // METADATA_KIND - [n x [id, name]]
1381   SmallVector<StringRef, 8> Names;
1382   M->getMDKindNames(Names);
1383
1384   if (Names.empty()) return;
1385
1386   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1387
1388   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1389     Record.push_back(MDKindID);
1390     StringRef KName = Names[MDKindID];
1391     Record.append(KName.begin(), KName.end());
1392
1393     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1394     Record.clear();
1395   }
1396
1397   Stream.ExitBlock();
1398 }
1399
1400 static void WriteOperandBundleTags(const Module *M, BitstreamWriter &Stream) {
1401   // Write metadata kinds
1402   //
1403   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1404   //
1405   // OPERAND_BUNDLE_TAG - [strchr x N]
1406
1407   SmallVector<StringRef, 8> Tags;
1408   M->getOperandBundleTags(Tags);
1409
1410   if (Tags.empty())
1411     return;
1412
1413   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1414
1415   SmallVector<uint64_t, 64> Record;
1416
1417   for (auto Tag : Tags) {
1418     Record.append(Tag.begin(), Tag.end());
1419
1420     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1421     Record.clear();
1422   }
1423
1424   Stream.ExitBlock();
1425 }
1426
1427 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1428   if ((int64_t)V >= 0)
1429     Vals.push_back(V << 1);
1430   else
1431     Vals.push_back((-V << 1) | 1);
1432 }
1433
1434 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1435                            const ValueEnumerator &VE,
1436                            BitstreamWriter &Stream, bool isGlobal) {
1437   if (FirstVal == LastVal) return;
1438
1439   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1440
1441   unsigned AggregateAbbrev = 0;
1442   unsigned String8Abbrev = 0;
1443   unsigned CString7Abbrev = 0;
1444   unsigned CString6Abbrev = 0;
1445   // If this is a constant pool for the module, emit module-specific abbrevs.
1446   if (isGlobal) {
1447     // Abbrev for CST_CODE_AGGREGATE.
1448     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1449     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1452     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1453
1454     // Abbrev for CST_CODE_STRING.
1455     Abbv = new BitCodeAbbrev();
1456     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1459     String8Abbrev = Stream.EmitAbbrev(Abbv);
1460     // Abbrev for CST_CODE_CSTRING.
1461     Abbv = new BitCodeAbbrev();
1462     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1465     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1466     // Abbrev for CST_CODE_CSTRING.
1467     Abbv = new BitCodeAbbrev();
1468     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1471     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1472   }
1473
1474   SmallVector<uint64_t, 64> Record;
1475
1476   const ValueEnumerator::ValueList &Vals = VE.getValues();
1477   Type *LastTy = nullptr;
1478   for (unsigned i = FirstVal; i != LastVal; ++i) {
1479     const Value *V = Vals[i].first;
1480     // If we need to switch types, do so now.
1481     if (V->getType() != LastTy) {
1482       LastTy = V->getType();
1483       Record.push_back(VE.getTypeID(LastTy));
1484       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1485                         CONSTANTS_SETTYPE_ABBREV);
1486       Record.clear();
1487     }
1488
1489     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1490       Record.push_back(unsigned(IA->hasSideEffects()) |
1491                        unsigned(IA->isAlignStack()) << 1 |
1492                        unsigned(IA->getDialect()&1) << 2);
1493
1494       // Add the asm string.
1495       const std::string &AsmStr = IA->getAsmString();
1496       Record.push_back(AsmStr.size());
1497       Record.append(AsmStr.begin(), AsmStr.end());
1498
1499       // Add the constraint string.
1500       const std::string &ConstraintStr = IA->getConstraintString();
1501       Record.push_back(ConstraintStr.size());
1502       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1503       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1504       Record.clear();
1505       continue;
1506     }
1507     const Constant *C = cast<Constant>(V);
1508     unsigned Code = -1U;
1509     unsigned AbbrevToUse = 0;
1510     if (C->isNullValue()) {
1511       Code = bitc::CST_CODE_NULL;
1512     } else if (isa<UndefValue>(C)) {
1513       Code = bitc::CST_CODE_UNDEF;
1514     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1515       if (IV->getBitWidth() <= 64) {
1516         uint64_t V = IV->getSExtValue();
1517         emitSignedInt64(Record, V);
1518         Code = bitc::CST_CODE_INTEGER;
1519         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1520       } else {                             // Wide integers, > 64 bits in size.
1521         // We have an arbitrary precision integer value to write whose
1522         // bit width is > 64. However, in canonical unsigned integer
1523         // format it is likely that the high bits are going to be zero.
1524         // So, we only write the number of active words.
1525         unsigned NWords = IV->getValue().getActiveWords();
1526         const uint64_t *RawWords = IV->getValue().getRawData();
1527         for (unsigned i = 0; i != NWords; ++i) {
1528           emitSignedInt64(Record, RawWords[i]);
1529         }
1530         Code = bitc::CST_CODE_WIDE_INTEGER;
1531       }
1532     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1533       Code = bitc::CST_CODE_FLOAT;
1534       Type *Ty = CFP->getType();
1535       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1536         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1537       } else if (Ty->isX86_FP80Ty()) {
1538         // api needed to prevent premature destruction
1539         // bits are not in the same order as a normal i80 APInt, compensate.
1540         APInt api = CFP->getValueAPF().bitcastToAPInt();
1541         const uint64_t *p = api.getRawData();
1542         Record.push_back((p[1] << 48) | (p[0] >> 16));
1543         Record.push_back(p[0] & 0xffffLL);
1544       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1545         APInt api = CFP->getValueAPF().bitcastToAPInt();
1546         const uint64_t *p = api.getRawData();
1547         Record.push_back(p[0]);
1548         Record.push_back(p[1]);
1549       } else {
1550         assert (0 && "Unknown FP type!");
1551       }
1552     } else if (isa<ConstantDataSequential>(C) &&
1553                cast<ConstantDataSequential>(C)->isString()) {
1554       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1555       // Emit constant strings specially.
1556       unsigned NumElts = Str->getNumElements();
1557       // If this is a null-terminated string, use the denser CSTRING encoding.
1558       if (Str->isCString()) {
1559         Code = bitc::CST_CODE_CSTRING;
1560         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1561       } else {
1562         Code = bitc::CST_CODE_STRING;
1563         AbbrevToUse = String8Abbrev;
1564       }
1565       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1566       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1567       for (unsigned i = 0; i != NumElts; ++i) {
1568         unsigned char V = Str->getElementAsInteger(i);
1569         Record.push_back(V);
1570         isCStr7 &= (V & 128) == 0;
1571         if (isCStrChar6)
1572           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1573       }
1574
1575       if (isCStrChar6)
1576         AbbrevToUse = CString6Abbrev;
1577       else if (isCStr7)
1578         AbbrevToUse = CString7Abbrev;
1579     } else if (const ConstantDataSequential *CDS =
1580                   dyn_cast<ConstantDataSequential>(C)) {
1581       Code = bitc::CST_CODE_DATA;
1582       Type *EltTy = CDS->getType()->getElementType();
1583       if (isa<IntegerType>(EltTy)) {
1584         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1585           Record.push_back(CDS->getElementAsInteger(i));
1586       } else if (EltTy->isFloatTy()) {
1587         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1588           union { float F; uint32_t I; };
1589           F = CDS->getElementAsFloat(i);
1590           Record.push_back(I);
1591         }
1592       } else {
1593         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1594         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1595           union { double F; uint64_t I; };
1596           F = CDS->getElementAsDouble(i);
1597           Record.push_back(I);
1598         }
1599       }
1600     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1601                isa<ConstantVector>(C)) {
1602       Code = bitc::CST_CODE_AGGREGATE;
1603       for (const Value *Op : C->operands())
1604         Record.push_back(VE.getValueID(Op));
1605       AbbrevToUse = AggregateAbbrev;
1606     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1607       switch (CE->getOpcode()) {
1608       default:
1609         if (Instruction::isCast(CE->getOpcode())) {
1610           Code = bitc::CST_CODE_CE_CAST;
1611           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1612           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1613           Record.push_back(VE.getValueID(C->getOperand(0)));
1614           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1615         } else {
1616           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1617           Code = bitc::CST_CODE_CE_BINOP;
1618           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1619           Record.push_back(VE.getValueID(C->getOperand(0)));
1620           Record.push_back(VE.getValueID(C->getOperand(1)));
1621           uint64_t Flags = GetOptimizationFlags(CE);
1622           if (Flags != 0)
1623             Record.push_back(Flags);
1624         }
1625         break;
1626       case Instruction::GetElementPtr: {
1627         Code = bitc::CST_CODE_CE_GEP;
1628         const auto *GO = cast<GEPOperator>(C);
1629         if (GO->isInBounds())
1630           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1631         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1632         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1633           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1634           Record.push_back(VE.getValueID(C->getOperand(i)));
1635         }
1636         break;
1637       }
1638       case Instruction::Select:
1639         Code = bitc::CST_CODE_CE_SELECT;
1640         Record.push_back(VE.getValueID(C->getOperand(0)));
1641         Record.push_back(VE.getValueID(C->getOperand(1)));
1642         Record.push_back(VE.getValueID(C->getOperand(2)));
1643         break;
1644       case Instruction::ExtractElement:
1645         Code = bitc::CST_CODE_CE_EXTRACTELT;
1646         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1647         Record.push_back(VE.getValueID(C->getOperand(0)));
1648         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1649         Record.push_back(VE.getValueID(C->getOperand(1)));
1650         break;
1651       case Instruction::InsertElement:
1652         Code = bitc::CST_CODE_CE_INSERTELT;
1653         Record.push_back(VE.getValueID(C->getOperand(0)));
1654         Record.push_back(VE.getValueID(C->getOperand(1)));
1655         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1656         Record.push_back(VE.getValueID(C->getOperand(2)));
1657         break;
1658       case Instruction::ShuffleVector:
1659         // If the return type and argument types are the same, this is a
1660         // standard shufflevector instruction.  If the types are different,
1661         // then the shuffle is widening or truncating the input vectors, and
1662         // the argument type must also be encoded.
1663         if (C->getType() == C->getOperand(0)->getType()) {
1664           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1665         } else {
1666           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1667           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1668         }
1669         Record.push_back(VE.getValueID(C->getOperand(0)));
1670         Record.push_back(VE.getValueID(C->getOperand(1)));
1671         Record.push_back(VE.getValueID(C->getOperand(2)));
1672         break;
1673       case Instruction::ICmp:
1674       case Instruction::FCmp:
1675         Code = bitc::CST_CODE_CE_CMP;
1676         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1677         Record.push_back(VE.getValueID(C->getOperand(0)));
1678         Record.push_back(VE.getValueID(C->getOperand(1)));
1679         Record.push_back(CE->getPredicate());
1680         break;
1681       }
1682     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1683       Code = bitc::CST_CODE_BLOCKADDRESS;
1684       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1685       Record.push_back(VE.getValueID(BA->getFunction()));
1686       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1687     } else {
1688 #ifndef NDEBUG
1689       C->dump();
1690 #endif
1691       llvm_unreachable("Unknown constant!");
1692     }
1693     Stream.EmitRecord(Code, Record, AbbrevToUse);
1694     Record.clear();
1695   }
1696
1697   Stream.ExitBlock();
1698 }
1699
1700 static void WriteModuleConstants(const ValueEnumerator &VE,
1701                                  BitstreamWriter &Stream) {
1702   const ValueEnumerator::ValueList &Vals = VE.getValues();
1703
1704   // Find the first constant to emit, which is the first non-globalvalue value.
1705   // We know globalvalues have been emitted by WriteModuleInfo.
1706   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1707     if (!isa<GlobalValue>(Vals[i].first)) {
1708       WriteConstants(i, Vals.size(), VE, Stream, true);
1709       return;
1710     }
1711   }
1712 }
1713
1714 /// PushValueAndType - The file has to encode both the value and type id for
1715 /// many values, because we need to know what type to create for forward
1716 /// references.  However, most operands are not forward references, so this type
1717 /// field is not needed.
1718 ///
1719 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1720 /// instruction ID, then it is a forward reference, and it also includes the
1721 /// type ID.  The value ID that is written is encoded relative to the InstID.
1722 static bool PushValueAndType(const Value *V, unsigned InstID,
1723                              SmallVectorImpl<unsigned> &Vals,
1724                              ValueEnumerator &VE) {
1725   unsigned ValID = VE.getValueID(V);
1726   // Make encoding relative to the InstID.
1727   Vals.push_back(InstID - ValID);
1728   if (ValID >= InstID) {
1729     Vals.push_back(VE.getTypeID(V->getType()));
1730     return true;
1731   }
1732   return false;
1733 }
1734
1735 static void WriteOperandBundles(BitstreamWriter &Stream, ImmutableCallSite CS,
1736                                 unsigned InstID, ValueEnumerator &VE) {
1737   SmallVector<unsigned, 64> Record;
1738   LLVMContext &C = CS.getInstruction()->getContext();
1739
1740   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
1741     const auto &Bundle = CS.getOperandBundle(i);
1742     Record.push_back(C.getOperandBundleTagID(Bundle.Tag));
1743
1744     for (auto &Input : Bundle.Inputs)
1745       PushValueAndType(Input, InstID, Record, VE);
1746
1747     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
1748     Record.clear();
1749   }
1750 }
1751
1752 /// pushValue - Like PushValueAndType, but where the type of the value is
1753 /// omitted (perhaps it was already encoded in an earlier operand).
1754 static void pushValue(const Value *V, unsigned InstID,
1755                       SmallVectorImpl<unsigned> &Vals,
1756                       ValueEnumerator &VE) {
1757   unsigned ValID = VE.getValueID(V);
1758   Vals.push_back(InstID - ValID);
1759 }
1760
1761 static void pushValueSigned(const Value *V, unsigned InstID,
1762                             SmallVectorImpl<uint64_t> &Vals,
1763                             ValueEnumerator &VE) {
1764   unsigned ValID = VE.getValueID(V);
1765   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1766   emitSignedInt64(Vals, diff);
1767 }
1768
1769 /// WriteInstruction - Emit an instruction to the specified stream.
1770 static void WriteInstruction(const Instruction &I, unsigned InstID,
1771                              ValueEnumerator &VE, BitstreamWriter &Stream,
1772                              SmallVectorImpl<unsigned> &Vals) {
1773   unsigned Code = 0;
1774   unsigned AbbrevToUse = 0;
1775   VE.setInstructionID(&I);
1776   switch (I.getOpcode()) {
1777   default:
1778     if (Instruction::isCast(I.getOpcode())) {
1779       Code = bitc::FUNC_CODE_INST_CAST;
1780       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1781         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1782       Vals.push_back(VE.getTypeID(I.getType()));
1783       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1784     } else {
1785       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1786       Code = bitc::FUNC_CODE_INST_BINOP;
1787       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1788         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1789       pushValue(I.getOperand(1), InstID, Vals, VE);
1790       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1791       uint64_t Flags = GetOptimizationFlags(&I);
1792       if (Flags != 0) {
1793         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1794           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1795         Vals.push_back(Flags);
1796       }
1797     }
1798     break;
1799
1800   case Instruction::GetElementPtr: {
1801     Code = bitc::FUNC_CODE_INST_GEP;
1802     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1803     auto &GEPInst = cast<GetElementPtrInst>(I);
1804     Vals.push_back(GEPInst.isInBounds());
1805     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1806     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1807       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1808     break;
1809   }
1810   case Instruction::ExtractValue: {
1811     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1812     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1813     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1814     Vals.append(EVI->idx_begin(), EVI->idx_end());
1815     break;
1816   }
1817   case Instruction::InsertValue: {
1818     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1819     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1820     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1821     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1822     Vals.append(IVI->idx_begin(), IVI->idx_end());
1823     break;
1824   }
1825   case Instruction::Select:
1826     Code = bitc::FUNC_CODE_INST_VSELECT;
1827     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1828     pushValue(I.getOperand(2), InstID, Vals, VE);
1829     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1830     break;
1831   case Instruction::ExtractElement:
1832     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1833     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1834     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1835     break;
1836   case Instruction::InsertElement:
1837     Code = bitc::FUNC_CODE_INST_INSERTELT;
1838     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1839     pushValue(I.getOperand(1), InstID, Vals, VE);
1840     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1841     break;
1842   case Instruction::ShuffleVector:
1843     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1844     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1845     pushValue(I.getOperand(1), InstID, Vals, VE);
1846     pushValue(I.getOperand(2), InstID, Vals, VE);
1847     break;
1848   case Instruction::ICmp:
1849   case Instruction::FCmp: {
1850     // compare returning Int1Ty or vector of Int1Ty
1851     Code = bitc::FUNC_CODE_INST_CMP2;
1852     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1853     pushValue(I.getOperand(1), InstID, Vals, VE);
1854     Vals.push_back(cast<CmpInst>(I).getPredicate());
1855     uint64_t Flags = GetOptimizationFlags(&I);
1856     if (Flags != 0)
1857       Vals.push_back(Flags);
1858     break;
1859   }
1860
1861   case Instruction::Ret:
1862     {
1863       Code = bitc::FUNC_CODE_INST_RET;
1864       unsigned NumOperands = I.getNumOperands();
1865       if (NumOperands == 0)
1866         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1867       else if (NumOperands == 1) {
1868         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1869           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1870       } else {
1871         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1872           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1873       }
1874     }
1875     break;
1876   case Instruction::Br:
1877     {
1878       Code = bitc::FUNC_CODE_INST_BR;
1879       const BranchInst &II = cast<BranchInst>(I);
1880       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1881       if (II.isConditional()) {
1882         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1883         pushValue(II.getCondition(), InstID, Vals, VE);
1884       }
1885     }
1886     break;
1887   case Instruction::Switch:
1888     {
1889       Code = bitc::FUNC_CODE_INST_SWITCH;
1890       const SwitchInst &SI = cast<SwitchInst>(I);
1891       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1892       pushValue(SI.getCondition(), InstID, Vals, VE);
1893       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1894       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1895            i != e; ++i) {
1896         Vals.push_back(VE.getValueID(i.getCaseValue()));
1897         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1898       }
1899     }
1900     break;
1901   case Instruction::IndirectBr:
1902     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1903     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1904     // Encode the address operand as relative, but not the basic blocks.
1905     pushValue(I.getOperand(0), InstID, Vals, VE);
1906     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1907       Vals.push_back(VE.getValueID(I.getOperand(i)));
1908     break;
1909
1910   case Instruction::Invoke: {
1911     const InvokeInst *II = cast<InvokeInst>(&I);
1912     const Value *Callee = II->getCalledValue();
1913     FunctionType *FTy = II->getFunctionType();
1914
1915     if (II->hasOperandBundles())
1916       WriteOperandBundles(Stream, II, InstID, VE);
1917
1918     Code = bitc::FUNC_CODE_INST_INVOKE;
1919
1920     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1921     Vals.push_back(II->getCallingConv() | 1 << 13);
1922     Vals.push_back(VE.getValueID(II->getNormalDest()));
1923     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1924     Vals.push_back(VE.getTypeID(FTy));
1925     PushValueAndType(Callee, InstID, Vals, VE);
1926
1927     // Emit value #'s for the fixed parameters.
1928     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1929       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1930
1931     // Emit type/value pairs for varargs params.
1932     if (FTy->isVarArg()) {
1933       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1934            i != e; ++i)
1935         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1936     }
1937     break;
1938   }
1939   case Instruction::Resume:
1940     Code = bitc::FUNC_CODE_INST_RESUME;
1941     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1942     break;
1943   case Instruction::CleanupRet: {
1944     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
1945     const auto &CRI = cast<CleanupReturnInst>(I);
1946     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
1947     if (CRI.hasUnwindDest())
1948       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
1949     break;
1950   }
1951   case Instruction::CatchRet: {
1952     Code = bitc::FUNC_CODE_INST_CATCHRET;
1953     const auto &CRI = cast<CatchReturnInst>(I);
1954     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
1955     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
1956     break;
1957   }
1958   case Instruction::CatchPad: {
1959     Code = bitc::FUNC_CODE_INST_CATCHPAD;
1960     const auto &CPI = cast<CatchPadInst>(I);
1961     Vals.push_back(VE.getValueID(CPI.getNormalDest()));
1962     Vals.push_back(VE.getValueID(CPI.getUnwindDest()));
1963     unsigned NumArgOperands = CPI.getNumArgOperands();
1964     Vals.push_back(NumArgOperands);
1965     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1966       PushValueAndType(CPI.getArgOperand(Op), InstID, Vals, VE);
1967     break;
1968   }
1969   case Instruction::TerminatePad: {
1970     Code = bitc::FUNC_CODE_INST_TERMINATEPAD;
1971     const auto &TPI = cast<TerminatePadInst>(I);
1972     Vals.push_back(TPI.hasUnwindDest());
1973     if (TPI.hasUnwindDest())
1974       Vals.push_back(VE.getValueID(TPI.getUnwindDest()));
1975     unsigned NumArgOperands = TPI.getNumArgOperands();
1976     Vals.push_back(NumArgOperands);
1977     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1978       PushValueAndType(TPI.getArgOperand(Op), InstID, Vals, VE);
1979     break;
1980   }
1981   case Instruction::CleanupPad: {
1982     Code = bitc::FUNC_CODE_INST_CLEANUPPAD;
1983     const auto &CPI = cast<CleanupPadInst>(I);
1984     unsigned NumOperands = CPI.getNumOperands();
1985     Vals.push_back(NumOperands);
1986     for (unsigned Op = 0; Op != NumOperands; ++Op)
1987       PushValueAndType(CPI.getOperand(Op), InstID, Vals, VE);
1988     break;
1989   }
1990   case Instruction::CatchEndPad: {
1991     Code = bitc::FUNC_CODE_INST_CATCHENDPAD;
1992     const auto &CEPI = cast<CatchEndPadInst>(I);
1993     if (CEPI.hasUnwindDest())
1994       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
1995     break;
1996   }
1997   case Instruction::CleanupEndPad: {
1998     Code = bitc::FUNC_CODE_INST_CLEANUPENDPAD;
1999     const auto &CEPI = cast<CleanupEndPadInst>(I);
2000     pushValue(CEPI.getCleanupPad(), InstID, Vals, VE);
2001     if (CEPI.hasUnwindDest())
2002       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
2003     break;
2004   }
2005   case Instruction::Unreachable:
2006     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2007     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2008     break;
2009
2010   case Instruction::PHI: {
2011     const PHINode &PN = cast<PHINode>(I);
2012     Code = bitc::FUNC_CODE_INST_PHI;
2013     // With the newer instruction encoding, forward references could give
2014     // negative valued IDs.  This is most common for PHIs, so we use
2015     // signed VBRs.
2016     SmallVector<uint64_t, 128> Vals64;
2017     Vals64.push_back(VE.getTypeID(PN.getType()));
2018     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2019       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
2020       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2021     }
2022     // Emit a Vals64 vector and exit.
2023     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2024     Vals64.clear();
2025     return;
2026   }
2027
2028   case Instruction::LandingPad: {
2029     const LandingPadInst &LP = cast<LandingPadInst>(I);
2030     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2031     Vals.push_back(VE.getTypeID(LP.getType()));
2032     Vals.push_back(LP.isCleanup());
2033     Vals.push_back(LP.getNumClauses());
2034     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2035       if (LP.isCatch(I))
2036         Vals.push_back(LandingPadInst::Catch);
2037       else
2038         Vals.push_back(LandingPadInst::Filter);
2039       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
2040     }
2041     break;
2042   }
2043
2044   case Instruction::Alloca: {
2045     Code = bitc::FUNC_CODE_INST_ALLOCA;
2046     const AllocaInst &AI = cast<AllocaInst>(I);
2047     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2048     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2049     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2050     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2051     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2052            "not enough bits for maximum alignment");
2053     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2054     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2055     AlignRecord |= 1 << 6;
2056     // Reserve bit 7 for SwiftError flag.
2057     // AlignRecord |= AI.isSwiftError() << 7;
2058     Vals.push_back(AlignRecord);
2059     break;
2060   }
2061
2062   case Instruction::Load:
2063     if (cast<LoadInst>(I).isAtomic()) {
2064       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2065       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2066     } else {
2067       Code = bitc::FUNC_CODE_INST_LOAD;
2068       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2069         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2070     }
2071     Vals.push_back(VE.getTypeID(I.getType()));
2072     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2073     Vals.push_back(cast<LoadInst>(I).isVolatile());
2074     if (cast<LoadInst>(I).isAtomic()) {
2075       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2076       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2077     }
2078     break;
2079   case Instruction::Store:
2080     if (cast<StoreInst>(I).isAtomic())
2081       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2082     else
2083       Code = bitc::FUNC_CODE_INST_STORE;
2084     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2085     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2086     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2087     Vals.push_back(cast<StoreInst>(I).isVolatile());
2088     if (cast<StoreInst>(I).isAtomic()) {
2089       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2090       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2091     }
2092     break;
2093   case Instruction::AtomicCmpXchg:
2094     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2095     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2096     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
2097     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2098     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2099     Vals.push_back(GetEncodedOrdering(
2100                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2101     Vals.push_back(GetEncodedSynchScope(
2102                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2103     Vals.push_back(GetEncodedOrdering(
2104                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2105     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2106     break;
2107   case Instruction::AtomicRMW:
2108     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2109     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2110     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2111     Vals.push_back(GetEncodedRMWOperation(
2112                      cast<AtomicRMWInst>(I).getOperation()));
2113     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2114     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2115     Vals.push_back(GetEncodedSynchScope(
2116                      cast<AtomicRMWInst>(I).getSynchScope()));
2117     break;
2118   case Instruction::Fence:
2119     Code = bitc::FUNC_CODE_INST_FENCE;
2120     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2121     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2122     break;
2123   case Instruction::Call: {
2124     const CallInst &CI = cast<CallInst>(I);
2125     FunctionType *FTy = CI.getFunctionType();
2126
2127     if (CI.hasOperandBundles())
2128       WriteOperandBundles(Stream, &CI, InstID, VE);
2129
2130     Code = bitc::FUNC_CODE_INST_CALL;
2131
2132     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2133     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
2134                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
2135     Vals.push_back(VE.getTypeID(FTy));
2136     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2137
2138     // Emit value #'s for the fixed parameters.
2139     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2140       // Check for labels (can happen with asm labels).
2141       if (FTy->getParamType(i)->isLabelTy())
2142         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2143       else
2144         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2145     }
2146
2147     // Emit type/value pairs for varargs params.
2148     if (FTy->isVarArg()) {
2149       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2150            i != e; ++i)
2151         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2152     }
2153     break;
2154   }
2155   case Instruction::VAArg:
2156     Code = bitc::FUNC_CODE_INST_VAARG;
2157     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2158     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2159     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2160     break;
2161   }
2162
2163   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2164   Vals.clear();
2165 }
2166
2167 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
2168
2169 /// Determine the encoding to use for the given string name and length.
2170 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
2171   bool isChar6 = true;
2172   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
2173     if (isChar6)
2174       isChar6 = BitCodeAbbrevOp::isChar6(*C);
2175     if ((unsigned char)*C & 128)
2176       // don't bother scanning the rest.
2177       return SE_Fixed8;
2178   }
2179   if (isChar6)
2180     return SE_Char6;
2181   else
2182     return SE_Fixed7;
2183 }
2184
2185 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2186 /// BitcodeStartBit and FunctionIndex are only passed for the module-level
2187 /// VST, where we are including a function bitcode index and need to
2188 /// backpatch the VST forward declaration record.
2189 static void WriteValueSymbolTable(
2190     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2191     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2192     uint64_t BitcodeStartBit = 0,
2193     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> *FunctionIndex =
2194         nullptr) {
2195   if (VST.empty()) {
2196     // WriteValueSymbolTableForwardDecl should have returned early as
2197     // well. Ensure this handling remains in sync by asserting that
2198     // the placeholder offset is not set.
2199     assert(VSTOffsetPlaceholder == 0);
2200     return;
2201   }
2202
2203   if (VSTOffsetPlaceholder > 0) {
2204     // Get the offset of the VST we are writing, and backpatch it into
2205     // the VST forward declaration record.
2206     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2207     // The BitcodeStartBit was the stream offset of the actual bitcode
2208     // (e.g. excluding any initial darwin header).
2209     VSTOffset -= BitcodeStartBit;
2210     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2211     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2212   }
2213
2214   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2215
2216   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2217   // records, which are not used in the per-function VSTs.
2218   unsigned FnEntry8BitAbbrev;
2219   unsigned FnEntry7BitAbbrev;
2220   unsigned FnEntry6BitAbbrev;
2221   if (VSTOffsetPlaceholder > 0) {
2222     // 8-bit fixed-width VST_FNENTRY function strings.
2223     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2224     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2228     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2229     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2230
2231     // 7-bit fixed width VST_FNENTRY function strings.
2232     Abbv = new BitCodeAbbrev();
2233     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2238     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2239
2240     // 6-bit char6 VST_FNENTRY function strings.
2241     Abbv = new BitCodeAbbrev();
2242     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2247     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2248   }
2249
2250   // FIXME: Set up the abbrev, we know how many values there are!
2251   // FIXME: We know if the type names can use 7-bit ascii.
2252   SmallVector<unsigned, 64> NameVals;
2253
2254   for (const ValueName &Name : VST) {
2255     // Figure out the encoding to use for the name.
2256     StringEncoding Bits =
2257         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2258
2259     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2260     NameVals.push_back(VE.getValueID(Name.getValue()));
2261
2262     Function *F = dyn_cast<Function>(Name.getValue());
2263     if (!F) {
2264       // If value is an alias, need to get the aliased base object to
2265       // see if it is a function.
2266       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2267       if (GA && GA->getBaseObject())
2268         F = dyn_cast<Function>(GA->getBaseObject());
2269     }
2270
2271     // VST_ENTRY:   [valueid, namechar x N]
2272     // VST_FNENTRY: [valueid, funcoffset, namechar x N]
2273     // VST_BBENTRY: [bbid, namechar x N]
2274     unsigned Code;
2275     if (isa<BasicBlock>(Name.getValue())) {
2276       Code = bitc::VST_CODE_BBENTRY;
2277       if (Bits == SE_Char6)
2278         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2279     } else if (F && !F->isDeclaration()) {
2280       // Must be the module-level VST, where we pass in the Index and
2281       // have a VSTOffsetPlaceholder. The function-level VST should not
2282       // contain any Function symbols.
2283       assert(FunctionIndex);
2284       assert(VSTOffsetPlaceholder > 0);
2285
2286       // Save the word offset of the function (from the start of the
2287       // actual bitcode written to the stream).
2288       assert(FunctionIndex->count(F) == 1);
2289       uint64_t BitcodeIndex =
2290           (*FunctionIndex)[F]->bitcodeIndex() - BitcodeStartBit;
2291       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2292       NameVals.push_back(BitcodeIndex / 32);
2293
2294       Code = bitc::VST_CODE_FNENTRY;
2295       AbbrevToUse = FnEntry8BitAbbrev;
2296       if (Bits == SE_Char6)
2297         AbbrevToUse = FnEntry6BitAbbrev;
2298       else if (Bits == SE_Fixed7)
2299         AbbrevToUse = FnEntry7BitAbbrev;
2300     } else {
2301       Code = bitc::VST_CODE_ENTRY;
2302       if (Bits == SE_Char6)
2303         AbbrevToUse = VST_ENTRY_6_ABBREV;
2304       else if (Bits == SE_Fixed7)
2305         AbbrevToUse = VST_ENTRY_7_ABBREV;
2306     }
2307
2308     for (const auto P : Name.getKey())
2309       NameVals.push_back((unsigned char)P);
2310
2311     // Emit the finished record.
2312     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2313     NameVals.clear();
2314   }
2315   Stream.ExitBlock();
2316 }
2317
2318 /// Emit function names and summary offsets for the combined index
2319 /// used by ThinLTO.
2320 static void WriteCombinedValueSymbolTable(const FunctionInfoIndex &Index,
2321                                           BitstreamWriter &Stream) {
2322   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2323
2324   // 8-bit fixed-width VST_COMBINED_FNENTRY function strings.
2325   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2326   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2330   unsigned FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2331
2332   // 7-bit fixed width VST_COMBINED_FNENTRY function strings.
2333   Abbv = new BitCodeAbbrev();
2334   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2337   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2338   unsigned FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2339
2340   // 6-bit char6 VST_COMBINED_FNENTRY function strings.
2341   Abbv = new BitCodeAbbrev();
2342   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2344   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2346   unsigned FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2347
2348   // FIXME: We know if the type names can use 7-bit ascii.
2349   SmallVector<unsigned, 64> NameVals;
2350
2351   for (const auto &FII : Index) {
2352     for (const auto &FI : FII.getValue()) {
2353       NameVals.push_back(FI->bitcodeIndex());
2354
2355       StringRef FuncName = FII.first();
2356
2357       // Figure out the encoding to use for the name.
2358       StringEncoding Bits = getStringEncoding(FuncName.data(), FuncName.size());
2359
2360       // VST_COMBINED_FNENTRY: [funcsumoffset, namechar x N]
2361       unsigned AbbrevToUse = FnEntry8BitAbbrev;
2362       if (Bits == SE_Char6)
2363         AbbrevToUse = FnEntry6BitAbbrev;
2364       else if (Bits == SE_Fixed7)
2365         AbbrevToUse = FnEntry7BitAbbrev;
2366
2367       for (const auto P : FuncName)
2368         NameVals.push_back((unsigned char)P);
2369
2370       // Emit the finished record.
2371       Stream.EmitRecord(bitc::VST_CODE_COMBINED_FNENTRY, NameVals, AbbrevToUse);
2372       NameVals.clear();
2373     }
2374   }
2375   Stream.ExitBlock();
2376 }
2377
2378 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2379                          BitstreamWriter &Stream) {
2380   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2381   unsigned Code;
2382   if (isa<BasicBlock>(Order.V))
2383     Code = bitc::USELIST_CODE_BB;
2384   else
2385     Code = bitc::USELIST_CODE_DEFAULT;
2386
2387   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2388   Record.push_back(VE.getValueID(Order.V));
2389   Stream.EmitRecord(Code, Record);
2390 }
2391
2392 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2393                               BitstreamWriter &Stream) {
2394   assert(VE.shouldPreserveUseListOrder() &&
2395          "Expected to be preserving use-list order");
2396
2397   auto hasMore = [&]() {
2398     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2399   };
2400   if (!hasMore())
2401     // Nothing to do.
2402     return;
2403
2404   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2405   while (hasMore()) {
2406     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2407     VE.UseListOrders.pop_back();
2408   }
2409   Stream.ExitBlock();
2410 }
2411
2412 /// \brief Save information for the given function into the function index.
2413 ///
2414 /// At a minimum this saves the bitcode index of the function record that
2415 /// was just written. However, if we are emitting function summary information,
2416 /// for example for ThinLTO, then a \a FunctionSummary object is created
2417 /// to hold the provided summary information.
2418 static void SaveFunctionInfo(
2419     const Function &F,
2420     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2421     unsigned NumInsts, uint64_t BitcodeIndex, bool EmitFunctionSummary) {
2422   std::unique_ptr<FunctionSummary> FuncSummary;
2423   if (EmitFunctionSummary) {
2424     FuncSummary = llvm::make_unique<FunctionSummary>(NumInsts);
2425     FuncSummary->setLocalFunction(F.hasLocalLinkage());
2426   }
2427   FunctionIndex[&F] =
2428       llvm::make_unique<FunctionInfo>(BitcodeIndex, std::move(FuncSummary));
2429 }
2430
2431 /// Emit a function body to the module stream.
2432 static void WriteFunction(
2433     const Function &F, ValueEnumerator &VE, BitstreamWriter &Stream,
2434     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2435     bool EmitFunctionSummary) {
2436   // Save the bitcode index of the start of this function block for recording
2437   // in the VST.
2438   uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
2439
2440   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2441   VE.incorporateFunction(F);
2442
2443   SmallVector<unsigned, 64> Vals;
2444
2445   // Emit the number of basic blocks, so the reader can create them ahead of
2446   // time.
2447   Vals.push_back(VE.getBasicBlocks().size());
2448   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2449   Vals.clear();
2450
2451   // If there are function-local constants, emit them now.
2452   unsigned CstStart, CstEnd;
2453   VE.getFunctionConstantRange(CstStart, CstEnd);
2454   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2455
2456   // If there is function-local metadata, emit it now.
2457   WriteFunctionLocalMetadata(F, VE, Stream);
2458
2459   // Keep a running idea of what the instruction ID is.
2460   unsigned InstID = CstEnd;
2461
2462   bool NeedsMetadataAttachment = F.hasMetadata();
2463
2464   DILocation *LastDL = nullptr;
2465   unsigned NumInsts = 0;
2466
2467   // Finally, emit all the instructions, in order.
2468   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2469     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2470          I != E; ++I) {
2471       WriteInstruction(*I, InstID, VE, Stream, Vals);
2472
2473       if (!isa<DbgInfoIntrinsic>(I))
2474         ++NumInsts;
2475
2476       if (!I->getType()->isVoidTy())
2477         ++InstID;
2478
2479       // If the instruction has metadata, write a metadata attachment later.
2480       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2481
2482       // If the instruction has a debug location, emit it.
2483       DILocation *DL = I->getDebugLoc();
2484       if (!DL)
2485         continue;
2486
2487       if (DL == LastDL) {
2488         // Just repeat the same debug loc as last time.
2489         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2490         continue;
2491       }
2492
2493       Vals.push_back(DL->getLine());
2494       Vals.push_back(DL->getColumn());
2495       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2496       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2497       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2498       Vals.clear();
2499
2500       LastDL = DL;
2501     }
2502
2503   // Emit names for all the instructions etc.
2504   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2505
2506   if (NeedsMetadataAttachment)
2507     WriteMetadataAttachment(F, VE, Stream);
2508   if (VE.shouldPreserveUseListOrder())
2509     WriteUseListBlock(&F, VE, Stream);
2510   VE.purgeFunction();
2511   Stream.ExitBlock();
2512
2513   SaveFunctionInfo(F, FunctionIndex, NumInsts, BitcodeIndex,
2514                    EmitFunctionSummary);
2515 }
2516
2517 // Emit blockinfo, which defines the standard abbreviations etc.
2518 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2519   // We only want to emit block info records for blocks that have multiple
2520   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2521   // Other blocks can define their abbrevs inline.
2522   Stream.EnterBlockInfoBlock(2);
2523
2524   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2525     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2530     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2531                                    Abbv) != VST_ENTRY_8_ABBREV)
2532       llvm_unreachable("Unexpected abbrev ordering!");
2533   }
2534
2535   { // 7-bit fixed width VST_ENTRY strings.
2536     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2537     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2541     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2542                                    Abbv) != VST_ENTRY_7_ABBREV)
2543       llvm_unreachable("Unexpected abbrev ordering!");
2544   }
2545   { // 6-bit char6 VST_ENTRY strings.
2546     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2547     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2551     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2552                                    Abbv) != VST_ENTRY_6_ABBREV)
2553       llvm_unreachable("Unexpected abbrev ordering!");
2554   }
2555   { // 6-bit char6 VST_BBENTRY strings.
2556     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2557     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2561     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2562                                    Abbv) != VST_BBENTRY_6_ABBREV)
2563       llvm_unreachable("Unexpected abbrev ordering!");
2564   }
2565
2566
2567
2568   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2569     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2570     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2572                               VE.computeBitsRequiredForTypeIndicies()));
2573     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2574                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2575       llvm_unreachable("Unexpected abbrev ordering!");
2576   }
2577
2578   { // INTEGER abbrev for CONSTANTS_BLOCK.
2579     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2580     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2582     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2583                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2584       llvm_unreachable("Unexpected abbrev ordering!");
2585   }
2586
2587   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2588     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2589     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2592                               VE.computeBitsRequiredForTypeIndicies()));
2593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2594
2595     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2596                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2597       llvm_unreachable("Unexpected abbrev ordering!");
2598   }
2599   { // NULL abbrev for CONSTANTS_BLOCK.
2600     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2601     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2602     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2603                                    Abbv) != CONSTANTS_NULL_Abbrev)
2604       llvm_unreachable("Unexpected abbrev ordering!");
2605   }
2606
2607   // FIXME: This should only use space for first class types!
2608
2609   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2610     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2611     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2614                               VE.computeBitsRequiredForTypeIndicies()));
2615     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2616     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2617     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2618                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2619       llvm_unreachable("Unexpected abbrev ordering!");
2620   }
2621   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2622     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2623     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2624     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2625     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2626     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2627     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2628                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2629       llvm_unreachable("Unexpected abbrev ordering!");
2630   }
2631   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2632     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2633     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2637     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2638     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2639                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2640       llvm_unreachable("Unexpected abbrev ordering!");
2641   }
2642   { // INST_CAST abbrev for FUNCTION_BLOCK.
2643     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2644     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2645     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2647                               VE.computeBitsRequiredForTypeIndicies()));
2648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2649     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2650                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2651       llvm_unreachable("Unexpected abbrev ordering!");
2652   }
2653
2654   { // INST_RET abbrev for FUNCTION_BLOCK.
2655     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2656     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2657     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2658                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2659       llvm_unreachable("Unexpected abbrev ordering!");
2660   }
2661   { // INST_RET abbrev for FUNCTION_BLOCK.
2662     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2663     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2665     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2666                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2667       llvm_unreachable("Unexpected abbrev ordering!");
2668   }
2669   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2670     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2671     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2672     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2673                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2674       llvm_unreachable("Unexpected abbrev ordering!");
2675   }
2676   {
2677     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2678     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2681                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2682     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2683     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2684     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2685         FUNCTION_INST_GEP_ABBREV)
2686       llvm_unreachable("Unexpected abbrev ordering!");
2687   }
2688
2689   Stream.ExitBlock();
2690 }
2691
2692 /// Write the module path strings, currently only used when generating
2693 /// a combined index file.
2694 static void WriteModStrings(const FunctionInfoIndex &I,
2695                             BitstreamWriter &Stream) {
2696   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2697
2698   // TODO: See which abbrev sizes we actually need to emit
2699
2700   // 8-bit fixed-width MST_ENTRY strings.
2701   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2702   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2703   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2704   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2705   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2706   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2707
2708   // 7-bit fixed width MST_ENTRY strings.
2709   Abbv = new BitCodeAbbrev();
2710   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2711   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2712   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2713   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2714   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2715
2716   // 6-bit char6 MST_ENTRY strings.
2717   Abbv = new BitCodeAbbrev();
2718   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2719   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2720   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2721   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2722   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2723
2724   SmallVector<unsigned, 64> NameVals;
2725   for (const StringMapEntry<uint64_t> &MPSE : I.modPathStringEntries()) {
2726     StringEncoding Bits =
2727         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2728     unsigned AbbrevToUse = Abbrev8Bit;
2729     if (Bits == SE_Char6)
2730       AbbrevToUse = Abbrev6Bit;
2731     else if (Bits == SE_Fixed7)
2732       AbbrevToUse = Abbrev7Bit;
2733
2734     NameVals.push_back(MPSE.getValue());
2735
2736     for (const auto P : MPSE.getKey())
2737       NameVals.push_back((unsigned char)P);
2738
2739     // Emit the finished record.
2740     Stream.EmitRecord(bitc::MST_CODE_ENTRY, NameVals, AbbrevToUse);
2741     NameVals.clear();
2742   }
2743   Stream.ExitBlock();
2744 }
2745
2746 // Helper to emit a single function summary record.
2747 static void WritePerModuleFunctionSummaryRecord(
2748     SmallVector<unsigned, 64> &NameVals, FunctionSummary *FS, unsigned ValueID,
2749     unsigned FSAbbrev, BitstreamWriter &Stream) {
2750   assert(FS);
2751   NameVals.push_back(ValueID);
2752   NameVals.push_back(FS->isLocalFunction());
2753   NameVals.push_back(FS->instCount());
2754
2755   // Emit the finished record.
2756   Stream.EmitRecord(bitc::FS_CODE_PERMODULE_ENTRY, NameVals, FSAbbrev);
2757   NameVals.clear();
2758 }
2759
2760 /// Emit the per-module function summary section alongside the rest of
2761 /// the module's bitcode.
2762 static void WritePerModuleFunctionSummary(
2763     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2764     const Module *M, const ValueEnumerator &VE, BitstreamWriter &Stream) {
2765   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2766
2767   // Abbrev for FS_CODE_PERMODULE_ENTRY.
2768   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2769   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_PERMODULE_ENTRY));
2770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
2771   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // islocal
2772   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2773   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2774
2775   SmallVector<unsigned, 64> NameVals;
2776   for (auto &I : FunctionIndex) {
2777     // Skip anonymous functions. We will emit a function summary for
2778     // any aliases below.
2779     if (!I.first->hasName())
2780       continue;
2781
2782     WritePerModuleFunctionSummaryRecord(
2783         NameVals, I.second->functionSummary(),
2784         VE.getValueID(M->getValueSymbolTable().lookup(I.first->getName())),
2785         FSAbbrev, Stream);
2786   }
2787
2788   for (const GlobalAlias &A : M->aliases()) {
2789     if (!A.getBaseObject())
2790       continue;
2791     const Function *F = dyn_cast<Function>(A.getBaseObject());
2792     if (!F || F->isDeclaration())
2793       continue;
2794
2795     assert(FunctionIndex.count(F) == 1);
2796     WritePerModuleFunctionSummaryRecord(
2797         NameVals, FunctionIndex[F]->functionSummary(),
2798         VE.getValueID(M->getValueSymbolTable().lookup(A.getName())), FSAbbrev,
2799         Stream);
2800   }
2801
2802   Stream.ExitBlock();
2803 }
2804
2805 /// Emit the combined function summary section into the combined index
2806 /// file.
2807 static void WriteCombinedFunctionSummary(const FunctionInfoIndex &I,
2808                                          BitstreamWriter &Stream) {
2809   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2810
2811   // Abbrev for FS_CODE_COMBINED_ENTRY.
2812   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2813   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_COMBINED_ENTRY));
2814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // modid
2815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // instcount
2816   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2817
2818   SmallVector<unsigned, 64> NameVals;
2819   for (const auto &FII : I) {
2820     for (auto &FI : FII.getValue()) {
2821       FunctionSummary *FS = FI->functionSummary();
2822       assert(FS);
2823
2824       NameVals.push_back(I.getModuleId(FS->modulePath()));
2825       NameVals.push_back(FS->instCount());
2826
2827       // Record the starting offset of this summary entry for use
2828       // in the VST entry. Add the current code size since the
2829       // reader will invoke readRecord after the abbrev id read.
2830       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
2831
2832       // Emit the finished record.
2833       Stream.EmitRecord(bitc::FS_CODE_COMBINED_ENTRY, NameVals, FSAbbrev);
2834       NameVals.clear();
2835     }
2836   }
2837
2838   Stream.ExitBlock();
2839 }
2840
2841 // Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
2842 // current llvm version, and a record for the epoch number.
2843 static void WriteIdentificationBlock(const Module *M, BitstreamWriter &Stream) {
2844   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
2845
2846   // Write the "user readable" string identifying the bitcode producer
2847   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2848   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
2849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2850   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2851   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
2852   WriteStringRecord(bitc::IDENTIFICATION_CODE_STRING,
2853                     "LLVM" LLVM_VERSION_STRING, StringAbbrev, Stream);
2854
2855   // Write the epoch version
2856   Abbv = new BitCodeAbbrev();
2857   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
2858   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2859   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
2860   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
2861   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
2862   Stream.ExitBlock();
2863 }
2864
2865 /// WriteModule - Emit the specified module to the bitstream.
2866 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2867                         bool ShouldPreserveUseListOrder,
2868                         uint64_t BitcodeStartBit, bool EmitFunctionSummary) {
2869   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2870
2871   SmallVector<unsigned, 1> Vals;
2872   unsigned CurVersion = 1;
2873   Vals.push_back(CurVersion);
2874   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2875
2876   // Analyze the module, enumerating globals, functions, etc.
2877   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2878
2879   // Emit blockinfo, which defines the standard abbreviations etc.
2880   WriteBlockInfo(VE, Stream);
2881
2882   // Emit information about attribute groups.
2883   WriteAttributeGroupTable(VE, Stream);
2884
2885   // Emit information about parameter attributes.
2886   WriteAttributeTable(VE, Stream);
2887
2888   // Emit information describing all of the types in the module.
2889   WriteTypeTable(VE, Stream);
2890
2891   writeComdats(VE, Stream);
2892
2893   // Emit top-level description of module, including target triple, inline asm,
2894   // descriptors for global variables, and function prototype info.
2895   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
2896
2897   // Emit constants.
2898   WriteModuleConstants(VE, Stream);
2899
2900   // Emit metadata.
2901   WriteModuleMetadata(M, VE, Stream);
2902
2903   // Emit metadata.
2904   WriteModuleMetadataStore(M, Stream);
2905
2906   // Emit module-level use-lists.
2907   if (VE.shouldPreserveUseListOrder())
2908     WriteUseListBlock(nullptr, VE, Stream);
2909
2910   WriteOperandBundleTags(M, Stream);
2911
2912   // Emit function bodies.
2913   DenseMap<const Function *, std::unique_ptr<FunctionInfo>> FunctionIndex;
2914   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2915     if (!F->isDeclaration())
2916       WriteFunction(*F, VE, Stream, FunctionIndex, EmitFunctionSummary);
2917
2918   // Need to write after the above call to WriteFunction which populates
2919   // the summary information in the index.
2920   if (EmitFunctionSummary)
2921     WritePerModuleFunctionSummary(FunctionIndex, M, VE, Stream);
2922
2923   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
2924                         VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
2925
2926   Stream.ExitBlock();
2927 }
2928
2929 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2930 /// header and trailer to make it compatible with the system archiver.  To do
2931 /// this we emit the following header, and then emit a trailer that pads the
2932 /// file out to be a multiple of 16 bytes.
2933 ///
2934 /// struct bc_header {
2935 ///   uint32_t Magic;         // 0x0B17C0DE
2936 ///   uint32_t Version;       // Version, currently always 0.
2937 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2938 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2939 ///   uint32_t CPUType;       // CPU specifier.
2940 ///   ... potentially more later ...
2941 /// };
2942 enum {
2943   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2944   DarwinBCHeaderSize = 5*4
2945 };
2946
2947 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2948                                uint32_t &Position) {
2949   support::endian::write32le(&Buffer[Position], Value);
2950   Position += 4;
2951 }
2952
2953 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2954                                          const Triple &TT) {
2955   unsigned CPUType = ~0U;
2956
2957   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2958   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2959   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2960   // specific constants here because they are implicitly part of the Darwin ABI.
2961   enum {
2962     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2963     DARWIN_CPU_TYPE_X86        = 7,
2964     DARWIN_CPU_TYPE_ARM        = 12,
2965     DARWIN_CPU_TYPE_POWERPC    = 18
2966   };
2967
2968   Triple::ArchType Arch = TT.getArch();
2969   if (Arch == Triple::x86_64)
2970     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2971   else if (Arch == Triple::x86)
2972     CPUType = DARWIN_CPU_TYPE_X86;
2973   else if (Arch == Triple::ppc)
2974     CPUType = DARWIN_CPU_TYPE_POWERPC;
2975   else if (Arch == Triple::ppc64)
2976     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2977   else if (Arch == Triple::arm || Arch == Triple::thumb)
2978     CPUType = DARWIN_CPU_TYPE_ARM;
2979
2980   // Traditional Bitcode starts after header.
2981   assert(Buffer.size() >= DarwinBCHeaderSize &&
2982          "Expected header size to be reserved");
2983   unsigned BCOffset = DarwinBCHeaderSize;
2984   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2985
2986   // Write the magic and version.
2987   unsigned Position = 0;
2988   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2989   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2990   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2991   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2992   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2993
2994   // If the file is not a multiple of 16 bytes, insert dummy padding.
2995   while (Buffer.size() & 15)
2996     Buffer.push_back(0);
2997 }
2998
2999 /// Helper to write the header common to all bitcode files.
3000 static void WriteBitcodeHeader(BitstreamWriter &Stream) {
3001   // Emit the file header.
3002   Stream.Emit((unsigned)'B', 8);
3003   Stream.Emit((unsigned)'C', 8);
3004   Stream.Emit(0x0, 4);
3005   Stream.Emit(0xC, 4);
3006   Stream.Emit(0xE, 4);
3007   Stream.Emit(0xD, 4);
3008 }
3009
3010 /// WriteBitcodeToFile - Write the specified module to the specified output
3011 /// stream.
3012 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3013                               bool ShouldPreserveUseListOrder,
3014                               bool EmitFunctionSummary) {
3015   SmallVector<char, 0> Buffer;
3016   Buffer.reserve(256*1024);
3017
3018   // If this is darwin or another generic macho target, reserve space for the
3019   // header.
3020   Triple TT(M->getTargetTriple());
3021   if (TT.isOSDarwin())
3022     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
3023
3024   // Emit the module into the buffer.
3025   {
3026     BitstreamWriter Stream(Buffer);
3027     // Save the start bit of the actual bitcode, in case there is space
3028     // saved at the start for the darwin header above. The reader stream
3029     // will start at the bitcode, and we need the offset of the VST
3030     // to line up.
3031     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
3032
3033     // Emit the file header.
3034     WriteBitcodeHeader(Stream);
3035
3036     WriteIdentificationBlock(M, Stream);
3037
3038     // Emit the module.
3039     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit,
3040                 EmitFunctionSummary);
3041   }
3042
3043   if (TT.isOSDarwin())
3044     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
3045
3046   // Write the generated bitstream to "Out".
3047   Out.write((char*)&Buffer.front(), Buffer.size());
3048 }
3049
3050 // Write the specified function summary index to the given raw output stream,
3051 // where it will be written in a new bitcode block. This is used when
3052 // writing the combined index file for ThinLTO.
3053 void llvm::WriteFunctionSummaryToFile(const FunctionInfoIndex &Index,
3054                                       raw_ostream &Out) {
3055   SmallVector<char, 0> Buffer;
3056   Buffer.reserve(256 * 1024);
3057
3058   BitstreamWriter Stream(Buffer);
3059
3060   // Emit the bitcode header.
3061   WriteBitcodeHeader(Stream);
3062
3063   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3064
3065   SmallVector<unsigned, 1> Vals;
3066   unsigned CurVersion = 1;
3067   Vals.push_back(CurVersion);
3068   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3069
3070   // Write the module paths in the combined index.
3071   WriteModStrings(Index, Stream);
3072
3073   // Write the function summary combined index records.
3074   WriteCombinedFunctionSummary(Index, Stream);
3075
3076   // Need a special VST writer for the combined index (we don't have a
3077   // real VST and real values when this is invoked).
3078   WriteCombinedValueSymbolTable(Index, Stream);
3079
3080   Stream.ExitBlock();
3081
3082   Out.write((char *)&Buffer.front(), Buffer.size());
3083 }