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::NonLazyBind:
 206     return bitc::ATTR_KIND_NON_LAZY_BIND;
 207   case Attribute::NonNull:
 208     return bitc::ATTR_KIND_NON_NULL;
 209   case Attribute::Dereferenceable:
 210     return bitc::ATTR_KIND_DEREFERENCEABLE;
 211   case Attribute::DereferenceableOrNull:
 212     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 213   case Attribute::NoRedZone:
 214     return bitc::ATTR_KIND_NO_RED_ZONE;
 215   case Attribute::NoReturn:
 216     return bitc::ATTR_KIND_NO_RETURN;
 217   case Attribute::NoUnwind:
 218     return bitc::ATTR_KIND_NO_UNWIND;
 219   case Attribute::OptimizeForSize:
 220     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 221   case Attribute::OptimizeNone:
 222     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 223   case Attribute::ReadNone:
 224     return bitc::ATTR_KIND_READ_NONE;
 225   case Attribute::ReadOnly:
 226     return bitc::ATTR_KIND_READ_ONLY;
 227   case Attribute::Returned:
 228     return bitc::ATTR_KIND_RETURNED;
 229   case Attribute::ReturnsTwice:
 230     return bitc::ATTR_KIND_RETURNS_TWICE;
 231   case Attribute::SExt:
 232     return bitc::ATTR_KIND_S_EXT;
 233   case Attribute::StackAlignment:
 234     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 235   case Attribute::StackProtect:
 236     return bitc::ATTR_KIND_STACK_PROTECT;
 237   case Attribute::StackProtectReq:
 238     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 239   case Attribute::StackProtectStrong:
 240     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 241   case Attribute::SafeStack:
 242     return bitc::ATTR_KIND_SAFESTACK;
 243   case Attribute::StructRet:
 244     return bitc::ATTR_KIND_STRUCT_RET;
 245   case Attribute::SanitizeAddress:
 246     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 247   case Attribute::SanitizeThread:
 248     return bitc::ATTR_KIND_SANITIZE_THREAD;
 249   case Attribute::SanitizeMemory:
 250     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 251   case Attribute::UWTable:
 252     return bitc::ATTR_KIND_UW_TABLE;
 253   case Attribute::ZExt:
 254     return bitc::ATTR_KIND_Z_EXT;
 255   case Attribute::EndAttrKinds:
 256     llvm_unreachable("Can not encode end-attribute kinds marker.");
 257   case Attribute::None:
 258     llvm_unreachable("Can not encode none-attribute.");
 259   }
 260
 261   llvm_unreachable("Trying to encode unknown attribute");
 262 }
 263
 264 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 265                                      BitstreamWriter &Stream) {
 266   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 267   if (AttrGrps.empty()) return;
 268
 269   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 270
 271   SmallVector<uint64_t, 64> Record;
 272   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 273     AttributeSet AS = AttrGrps[i];
 274     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 275       AttributeSet A = AS.getSlotAttributes(i);
 276
 277       Record.push_back(VE.getAttributeGroupID(A));
 278       Record.push_back(AS.getSlotIndex(i));
 279
 280       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 281            I != E; ++I) {
 282         Attribute Attr = *I;
 283         if (Attr.isEnumAttribute()) {
 284           Record.push_back(0);
 285           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 286         } else if (Attr.isIntAttribute()) {
 287           Record.push_back(1);
 288           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 289           Record.push_back(Attr.getValueAsInt());
 290         } else {
 291           StringRef Kind = Attr.getKindAsString();
 292           StringRef Val = Attr.getValueAsString();
 293
 294           Record.push_back(Val.empty() ? 3 : 4);
 295           Record.append(Kind.begin(), Kind.end());
 296           Record.push_back(0);
 297           if (!Val.empty()) {
 298             Record.append(Val.begin(), Val.end());
 299             Record.push_back(0);
 300           }
 301         }
 302       }
 303
 304       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 305       Record.clear();
 306     }
 307   }
 308
 309   Stream.ExitBlock();
 310 }
 311
 312 static void WriteAttributeTable(const ValueEnumerator &VE,
 313                                 BitstreamWriter &Stream) {
 314   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 315   if (Attrs.empty()) return;
 316
 317   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 318
 319   SmallVector<uint64_t, 64> Record;
 320   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 321     const AttributeSet &A = Attrs[i];
 322     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 323       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 324
 325     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 326     Record.clear();
 327   }
 328
 329   Stream.ExitBlock();
 330 }
 331
 332 /// WriteTypeTable - Write out the type table for a module.
 333 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 334   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 335
 336   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 337   SmallVector<uint64_t, 64> TypeVals;
 338
 339   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 340
 341   // Abbrev for TYPE_CODE_POINTER.
 342   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 343   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 344   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 345   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 346   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 347
 348   // Abbrev for TYPE_CODE_FUNCTION.
 349   Abbv = new BitCodeAbbrev();
 350   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 354
 355   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 356
 357   // Abbrev for TYPE_CODE_STRUCT_ANON.
 358   Abbv = new BitCodeAbbrev();
 359   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 363
 364   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 365
 366   // Abbrev for TYPE_CODE_STRUCT_NAME.
 367   Abbv = new BitCodeAbbrev();
 368   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 369   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 371   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 372
 373   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 374   Abbv = new BitCodeAbbrev();
 375   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 376   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 377   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 378   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 379
 380   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 381
 382   // Abbrev for TYPE_CODE_ARRAY.
 383   Abbv = new BitCodeAbbrev();
 384   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 386   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 387
 388   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 389
 390   // Emit an entry count so the reader can reserve space.
 391   TypeVals.push_back(TypeList.size());
 392   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 393   TypeVals.clear();
 394
 395   // Loop over all of the types, emitting each in turn.
 396   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 397     Type *T = TypeList[i];
 398     int AbbrevToUse = 0;
 399     unsigned Code = 0;
 400
 401     switch (T->getTypeID()) {
 402     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 403     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 404     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 405     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 406     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 407     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 408     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 409     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 410     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 411     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 412     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
 413     case Type::IntegerTyID:
 414       // INTEGER: [width]
 415       Code = bitc::TYPE_CODE_INTEGER;
 416       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 417       break;
 418     case Type::PointerTyID: {
 419       PointerType *PTy = cast<PointerType>(T);
 420       // POINTER: [pointee type, address space]
 421       Code = bitc::TYPE_CODE_POINTER;
 422       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 423       unsigned AddressSpace = PTy->getAddressSpace();
 424       TypeVals.push_back(AddressSpace);
 425       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 426       break;
 427     }
 428     case Type::FunctionTyID: {
 429       FunctionType *FT = cast<FunctionType>(T);
 430       // FUNCTION: [isvararg, retty, paramty x N]
 431       Code = bitc::TYPE_CODE_FUNCTION;
 432       TypeVals.push_back(FT->isVarArg());
 433       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 434       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 435         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 436       AbbrevToUse = FunctionAbbrev;
 437       break;
 438     }
 439     case Type::StructTyID: {
 440       StructType *ST = cast<StructType>(T);
 441       // STRUCT: [ispacked, eltty x N]
 442       TypeVals.push_back(ST->isPacked());
 443       // Output all of the element types.
 444       for (StructType::element_iterator I = ST->element_begin(),
 445            E = ST->element_end(); I != E; ++I)
 446         TypeVals.push_back(VE.getTypeID(*I));
 447
 448       if (ST->isLiteral()) {
 449         Code = bitc::TYPE_CODE_STRUCT_ANON;
 450         AbbrevToUse = StructAnonAbbrev;
 451       } else {
 452         if (ST->isOpaque()) {
 453           Code = bitc::TYPE_CODE_OPAQUE;
 454         } else {
 455           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 456           AbbrevToUse = StructNamedAbbrev;
 457         }
 458
 459         // Emit the name if it is present.
 460         if (!ST->getName().empty())
 461           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 462                             StructNameAbbrev, Stream);
 463       }
 464       break;
 465     }
 466     case Type::ArrayTyID: {
 467       ArrayType *AT = cast<ArrayType>(T);
 468       // ARRAY: [numelts, eltty]
 469       Code = bitc::TYPE_CODE_ARRAY;
 470       TypeVals.push_back(AT->getNumElements());
 471       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 472       AbbrevToUse = ArrayAbbrev;
 473       break;
 474     }
 475     case Type::VectorTyID: {
 476       VectorType *VT = cast<VectorType>(T);
 477       // VECTOR [numelts, eltty]
 478       Code = bitc::TYPE_CODE_VECTOR;
 479       TypeVals.push_back(VT->getNumElements());
 480       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 481       break;
 482     }
 483     }
 484
 485     // Emit the finished record.
 486     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 487     TypeVals.clear();
 488   }
 489
 490   Stream.ExitBlock();
 491 }
 492
 493 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 494   switch (GV.getLinkage()) {
 495   case GlobalValue::ExternalLinkage:
 496     return 0;
 497   case GlobalValue::WeakAnyLinkage:
 498     return 16;
 499   case GlobalValue::AppendingLinkage:
 500     return 2;
 501   case GlobalValue::InternalLinkage:
 502     return 3;
 503   case GlobalValue::LinkOnceAnyLinkage:
 504     return 18;
 505   case GlobalValue::ExternalWeakLinkage:
 506     return 7;
 507   case GlobalValue::CommonLinkage:
 508     return 8;
 509   case GlobalValue::PrivateLinkage:
 510     return 9;
 511   case GlobalValue::WeakODRLinkage:
 512     return 17;
 513   case GlobalValue::LinkOnceODRLinkage:
 514     return 19;
 515   case GlobalValue::AvailableExternallyLinkage:
 516     return 12;
 517   }
 518   llvm_unreachable("Invalid linkage");
 519 }
 520
 521 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 522   switch (GV.getVisibility()) {
 523   case GlobalValue::DefaultVisibility:   return 0;
 524   case GlobalValue::HiddenVisibility:    return 1;
 525   case GlobalValue::ProtectedVisibility: return 2;
 526   }
 527   llvm_unreachable("Invalid visibility");
 528 }
 529
 530 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 531   switch (GV.getDLLStorageClass()) {
 532   case GlobalValue::DefaultStorageClass:   return 0;
 533   case GlobalValue::DLLImportStorageClass: return 1;
 534   case GlobalValue::DLLExportStorageClass: return 2;
 535   }
 536   llvm_unreachable("Invalid DLL storage class");
 537 }
 538
 539 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 540   switch (GV.getThreadLocalMode()) {
 541     case GlobalVariable::NotThreadLocal:         return 0;
 542     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 543     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 544     case GlobalVariable::InitialExecTLSModel:    return 3;
 545     case GlobalVariable::LocalExecTLSModel:      return 4;
 546   }
 547   llvm_unreachable("Invalid TLS model");
 548 }
 549
 550 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 551   switch (C.getSelectionKind()) {
 552   case Comdat::Any:
 553     return bitc::COMDAT_SELECTION_KIND_ANY;
 554   case Comdat::ExactMatch:
 555     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 556   case Comdat::Largest:
 557     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 558   case Comdat::NoDuplicates:
 559     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 560   case Comdat::SameSize:
 561     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 562   }
 563   llvm_unreachable("Invalid selection kind");
 564 }
 565
 566 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 567   SmallVector<uint16_t, 64> Vals;
 568   for (const Comdat *C : VE.getComdats()) {
 569     // COMDAT: [selection_kind, name]
 570     Vals.push_back(getEncodedComdatSelectionKind(*C));
 571     size_t Size = C->getName().size();
 572     assert(isUInt<16>(Size));
 573     Vals.push_back(Size);
 574     for (char Chr : C->getName())
 575       Vals.push_back((unsigned char)Chr);
 576     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 577     Vals.clear();
 578   }
 579 }
 580
 581 /// Write a record that will eventually hold the word offset of the
 582 /// module-level VST. For now the offset is 0, which will be backpatched
 583 /// after the real VST is written. Returns the bit offset to backpatch.
 584 static uint64_t WriteValueSymbolTableForwardDecl(const ValueSymbolTable &VST,
 585                                                  BitstreamWriter &Stream) {
 586   if (VST.empty()) return 0;
 587
 588   // Write a placeholder value in for the offset of the real VST,
 589   // which is written after the function blocks so that it can include
 590   // the offset of each function. The placeholder offset will be
 591   // updated when the real VST is written.
 592   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 593   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
 594   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
 595   // hold the real VST offset. Must use fixed instead of VBR as we don't
 596   // know how many VBR chunks to reserve ahead of time.
 597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
 598   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
 599
 600   // Emit the placeholder
 601   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
 602   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
 603
 604   // Compute and return the bit offset to the placeholder, which will be
 605   // patched when the real VST is written. We can simply subtract the 32-bit
 606   // fixed size from the current bit number to get the location to backpatch.
 607   return Stream.GetCurrentBitNo() - 32;
 608 }
 609
 610 /// Emit top-level description of module, including target triple, inline asm,
 611 /// descriptors for global variables, and function prototype info.
 612 /// Returns the bit offset to backpatch with the location of the real VST.
 613 static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 614                                 BitstreamWriter &Stream) {
 615   // Emit various pieces of data attached to a module.
 616   if (!M->getTargetTriple().empty())
 617     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 618                       0/*TODO*/, Stream);
 619   const std::string &DL = M->getDataLayoutStr();
 620   if (!DL.empty())
 621     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 622   if (!M->getModuleInlineAsm().empty())
 623     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 624                       0/*TODO*/, Stream);
 625
 626   // Emit information about sections and GC, computing how many there are. Also
 627   // compute the maximum alignment value.
 628   std::map<std::string, unsigned> SectionMap;
 629   std::map<std::string, unsigned> GCMap;
 630   unsigned MaxAlignment = 0;
 631   unsigned MaxGlobalType = 0;
 632   for (const GlobalValue &GV : M->globals()) {
 633     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 634     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 635     if (GV.hasSection()) {
 636       // Give section names unique ID's.
 637       unsigned &Entry = SectionMap[GV.getSection()];
 638       if (!Entry) {
 639         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 640                           0/*TODO*/, Stream);
 641         Entry = SectionMap.size();
 642       }
 643     }
 644   }
 645   for (const Function &F : *M) {
 646     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 647     if (F.hasSection()) {
 648       // Give section names unique ID's.
 649       unsigned &Entry = SectionMap[F.getSection()];
 650       if (!Entry) {
 651         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 652                           0/*TODO*/, Stream);
 653         Entry = SectionMap.size();
 654       }
 655     }
 656     if (F.hasGC()) {
 657       // Same for GC names.
 658       unsigned &Entry = GCMap[F.getGC()];
 659       if (!Entry) {
 660         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 661                           0/*TODO*/, Stream);
 662         Entry = GCMap.size();
 663       }
 664     }
 665   }
 666
 667   // Emit abbrev for globals, now that we know # sections and max alignment.
 668   unsigned SimpleGVarAbbrev = 0;
 669   if (!M->global_empty()) {
 670     // Add an abbrev for common globals with no visibility or thread localness.
 671     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 672     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 673     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 674                               Log2_32_Ceil(MaxGlobalType+1)));
 675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 676                                                            //| explicitType << 1
 677                                                            //| constant
 678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 680     if (MaxAlignment == 0)                                 // Alignment.
 681       Abbv->Add(BitCodeAbbrevOp(0));
 682     else {
 683       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 684       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 685                                Log2_32_Ceil(MaxEncAlignment+1)));
 686     }
 687     if (SectionMap.empty())                                    // Section.
 688       Abbv->Add(BitCodeAbbrevOp(0));
 689     else
 690       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 691                                Log2_32_Ceil(SectionMap.size()+1)));
 692     // Don't bother emitting vis + thread local.
 693     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 694   }
 695
 696   // Emit the global variable information.
 697   SmallVector<unsigned, 64> Vals;
 698   for (const GlobalVariable &GV : M->globals()) {
 699     unsigned AbbrevToUse = 0;
 700
 701     // GLOBALVAR: [type, isconst, initid,
 702     //             linkage, alignment, section, visibility, threadlocal,
 703     //             unnamed_addr, externally_initialized, dllstorageclass,
 704     //             comdat]
 705     Vals.push_back(VE.getTypeID(GV.getValueType()));
 706     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 707     Vals.push_back(GV.isDeclaration() ? 0 :
 708                    (VE.getValueID(GV.getInitializer()) + 1));
 709     Vals.push_back(getEncodedLinkage(GV));
 710     Vals.push_back(Log2_32(GV.getAlignment())+1);
 711     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 712     if (GV.isThreadLocal() ||
 713         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 714         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 715         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 716         GV.hasComdat()) {
 717       Vals.push_back(getEncodedVisibility(GV));
 718       Vals.push_back(getEncodedThreadLocalMode(GV));
 719       Vals.push_back(GV.hasUnnamedAddr());
 720       Vals.push_back(GV.isExternallyInitialized());
 721       Vals.push_back(getEncodedDLLStorageClass(GV));
 722       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 723     } else {
 724       AbbrevToUse = SimpleGVarAbbrev;
 725     }
 726
 727     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 728     Vals.clear();
 729   }
 730
 731   // Emit the function proto information.
 732   for (const Function &F : *M) {
 733     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 734     //             section, visibility, gc, unnamed_addr, prologuedata,
 735     //             dllstorageclass, comdat, prefixdata, personalityfn]
 736     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 737     Vals.push_back(F.getCallingConv());
 738     Vals.push_back(F.isDeclaration());
 739     Vals.push_back(getEncodedLinkage(F));
 740     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 741     Vals.push_back(Log2_32(F.getAlignment())+1);
 742     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 743     Vals.push_back(getEncodedVisibility(F));
 744     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 745     Vals.push_back(F.hasUnnamedAddr());
 746     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 747                                        : 0);
 748     Vals.push_back(getEncodedDLLStorageClass(F));
 749     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 750     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 751                                      : 0);
 752     Vals.push_back(
 753         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
 754
 755     unsigned AbbrevToUse = 0;
 756     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 757     Vals.clear();
 758   }
 759
 760   // Emit the alias information.
 761   for (const GlobalAlias &A : M->aliases()) {
 762     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 763     Vals.push_back(VE.getTypeID(A.getValueType()));
 764     Vals.push_back(A.getType()->getAddressSpace());
 765     Vals.push_back(VE.getValueID(A.getAliasee()));
 766     Vals.push_back(getEncodedLinkage(A));
 767     Vals.push_back(getEncodedVisibility(A));
 768     Vals.push_back(getEncodedDLLStorageClass(A));
 769     Vals.push_back(getEncodedThreadLocalMode(A));
 770     Vals.push_back(A.hasUnnamedAddr());
 771     unsigned AbbrevToUse = 0;
 772     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 773     Vals.clear();
 774   }
 775
 776   uint64_t VSTOffsetPlaceholder =
 777       WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
 778   return VSTOffsetPlaceholder;
 779 }
 780
 781 static uint64_t GetOptimizationFlags(const Value *V) {
 782   uint64_t Flags = 0;
 783
 784   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 785     if (OBO->hasNoSignedWrap())
 786       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 787     if (OBO->hasNoUnsignedWrap())
 788       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 789   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 790     if (PEO->isExact())
 791       Flags |= 1 << bitc::PEO_EXACT;
 792   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 793     if (FPMO->hasUnsafeAlgebra())
 794       Flags |= FastMathFlags::UnsafeAlgebra;
 795     if (FPMO->hasNoNaNs())
 796       Flags |= FastMathFlags::NoNaNs;
 797     if (FPMO->hasNoInfs())
 798       Flags |= FastMathFlags::NoInfs;
 799     if (FPMO->hasNoSignedZeros())
 800       Flags |= FastMathFlags::NoSignedZeros;
 801     if (FPMO->hasAllowReciprocal())
 802       Flags |= FastMathFlags::AllowReciprocal;
 803   }
 804
 805   return Flags;
 806 }
 807
 808 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 809                                  const ValueEnumerator &VE,
 810                                  BitstreamWriter &Stream,
 811                                  SmallVectorImpl<uint64_t> &Record) {
 812   // Mimic an MDNode with a value as one operand.
 813   Value *V = MD->getValue();
 814   Record.push_back(VE.getTypeID(V->getType()));
 815   Record.push_back(VE.getValueID(V));
 816   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 817   Record.clear();
 818 }
 819
 820 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 821                          BitstreamWriter &Stream,
 822                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 823   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 824     Metadata *MD = N->getOperand(i);
 825     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 826            "Unexpected function-local metadata");
 827     Record.push_back(VE.getMetadataOrNullID(MD));
 828   }
 829   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 830                                     : bitc::METADATA_NODE,
 831                     Record, Abbrev);
 832   Record.clear();
 833 }
 834
 835 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 836                             BitstreamWriter &Stream,
 837                             SmallVectorImpl<uint64_t> &Record,
 838                             unsigned Abbrev) {
 839   Record.push_back(N->isDistinct());
 840   Record.push_back(N->getLine());
 841   Record.push_back(N->getColumn());
 842   Record.push_back(VE.getMetadataID(N->getScope()));
 843   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 844
 845   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 846   Record.clear();
 847 }
 848
 849 static void WriteGenericDINode(const GenericDINode *N,
 850                                const ValueEnumerator &VE,
 851                                BitstreamWriter &Stream,
 852                                SmallVectorImpl<uint64_t> &Record,
 853                                unsigned Abbrev) {
 854   Record.push_back(N->isDistinct());
 855   Record.push_back(N->getTag());
 856   Record.push_back(0); // Per-tag version field; unused for now.
 857
 858   for (auto &I : N->operands())
 859     Record.push_back(VE.getMetadataOrNullID(I));
 860
 861   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 862   Record.clear();
 863 }
 864
 865 static uint64_t rotateSign(int64_t I) {
 866   uint64_t U = I;
 867   return I < 0 ? ~(U << 1) : U << 1;
 868 }
 869
 870 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 871                             BitstreamWriter &Stream,
 872                             SmallVectorImpl<uint64_t> &Record,
 873                             unsigned Abbrev) {
 874   Record.push_back(N->isDistinct());
 875   Record.push_back(N->getCount());
 876   Record.push_back(rotateSign(N->getLowerBound()));
 877
 878   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 879   Record.clear();
 880 }
 881
 882 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 883                               BitstreamWriter &Stream,
 884                               SmallVectorImpl<uint64_t> &Record,
 885                               unsigned Abbrev) {
 886   Record.push_back(N->isDistinct());
 887   Record.push_back(rotateSign(N->getValue()));
 888   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 889
 890   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 891   Record.clear();
 892 }
 893
 894 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 895                              BitstreamWriter &Stream,
 896                              SmallVectorImpl<uint64_t> &Record,
 897                              unsigned Abbrev) {
 898   Record.push_back(N->isDistinct());
 899   Record.push_back(N->getTag());
 900   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 901   Record.push_back(N->getSizeInBits());
 902   Record.push_back(N->getAlignInBits());
 903   Record.push_back(N->getEncoding());
 904
 905   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 906   Record.clear();
 907 }
 908
 909 static void WriteDIDerivedType(const DIDerivedType *N,
 910                                const ValueEnumerator &VE,
 911                                BitstreamWriter &Stream,
 912                                SmallVectorImpl<uint64_t> &Record,
 913                                unsigned Abbrev) {
 914   Record.push_back(N->isDistinct());
 915   Record.push_back(N->getTag());
 916   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 917   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 918   Record.push_back(N->getLine());
 919   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 920   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 921   Record.push_back(N->getSizeInBits());
 922   Record.push_back(N->getAlignInBits());
 923   Record.push_back(N->getOffsetInBits());
 924   Record.push_back(N->getFlags());
 925   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 926
 927   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 928   Record.clear();
 929 }
 930
 931 static void WriteDICompositeType(const DICompositeType *N,
 932                                  const ValueEnumerator &VE,
 933                                  BitstreamWriter &Stream,
 934                                  SmallVectorImpl<uint64_t> &Record,
 935                                  unsigned Abbrev) {
 936   Record.push_back(N->isDistinct());
 937   Record.push_back(N->getTag());
 938   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 939   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 940   Record.push_back(N->getLine());
 941   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 942   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 943   Record.push_back(N->getSizeInBits());
 944   Record.push_back(N->getAlignInBits());
 945   Record.push_back(N->getOffsetInBits());
 946   Record.push_back(N->getFlags());
 947   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 948   Record.push_back(N->getRuntimeLang());
 949   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 950   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 951   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 952
 953   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 954   Record.clear();
 955 }
 956
 957 static void WriteDISubroutineType(const DISubroutineType *N,
 958                                   const ValueEnumerator &VE,
 959                                   BitstreamWriter &Stream,
 960                                   SmallVectorImpl<uint64_t> &Record,
 961                                   unsigned Abbrev) {
 962   Record.push_back(N->isDistinct());
 963   Record.push_back(N->getFlags());
 964   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 965
 966   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 967   Record.clear();
 968 }
 969
 970 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 971                         BitstreamWriter &Stream,
 972                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 973   Record.push_back(N->isDistinct());
 974   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 975   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 976
 977   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 978   Record.clear();
 979 }
 980
 981 static void WriteDICompileUnit(const DICompileUnit *N,
 982                                const ValueEnumerator &VE,
 983                                BitstreamWriter &Stream,
 984                                SmallVectorImpl<uint64_t> &Record,
 985                                unsigned Abbrev) {
 986   assert(N->isDistinct() && "Expected distinct compile units");
 987   Record.push_back(/* IsDistinct */ true);
 988   Record.push_back(N->getSourceLanguage());
 989   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 990   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 991   Record.push_back(N->isOptimized());
 992   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 993   Record.push_back(N->getRuntimeVersion());
 994   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 995   Record.push_back(N->getEmissionKind());
 996   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 997   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 998   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 999   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1000   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1001   Record.push_back(N->getDWOId());
1002
1003   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1004   Record.clear();
1005 }
1006
1007 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1008                               BitstreamWriter &Stream,
1009                               SmallVectorImpl<uint64_t> &Record,
1010                               unsigned Abbrev) {
1011   Record.push_back(N->isDistinct());
1012   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1013   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1014   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1015   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1016   Record.push_back(N->getLine());
1017   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1018   Record.push_back(N->isLocalToUnit());
1019   Record.push_back(N->isDefinition());
1020   Record.push_back(N->getScopeLine());
1021   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1022   Record.push_back(N->getVirtuality());
1023   Record.push_back(N->getVirtualIndex());
1024   Record.push_back(N->getFlags());
1025   Record.push_back(N->isOptimized());
1026   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
1027   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1028   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1029   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1030
1031   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1032   Record.clear();
1033 }
1034
1035 static void WriteDILexicalBlock(const DILexicalBlock *N,
1036                                 const ValueEnumerator &VE,
1037                                 BitstreamWriter &Stream,
1038                                 SmallVectorImpl<uint64_t> &Record,
1039                                 unsigned Abbrev) {
1040   Record.push_back(N->isDistinct());
1041   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1042   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1043   Record.push_back(N->getLine());
1044   Record.push_back(N->getColumn());
1045
1046   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1047   Record.clear();
1048 }
1049
1050 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1051                                     const ValueEnumerator &VE,
1052                                     BitstreamWriter &Stream,
1053                                     SmallVectorImpl<uint64_t> &Record,
1054                                     unsigned Abbrev) {
1055   Record.push_back(N->isDistinct());
1056   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1057   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1058   Record.push_back(N->getDiscriminator());
1059
1060   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1061   Record.clear();
1062 }
1063
1064 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1065                              BitstreamWriter &Stream,
1066                              SmallVectorImpl<uint64_t> &Record,
1067                              unsigned Abbrev) {
1068   Record.push_back(N->isDistinct());
1069   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1070   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1071   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1072   Record.push_back(N->getLine());
1073
1074   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1075   Record.clear();
1076 }
1077
1078 static void WriteDIModule(const DIModule *N, const ValueEnumerator &VE,
1079                           BitstreamWriter &Stream,
1080                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1081   Record.push_back(N->isDistinct());
1082   for (auto &I : N->operands())
1083     Record.push_back(VE.getMetadataOrNullID(I));
1084
1085   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1086   Record.clear();
1087 }
1088
1089 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1090                                          const ValueEnumerator &VE,
1091                                          BitstreamWriter &Stream,
1092                                          SmallVectorImpl<uint64_t> &Record,
1093                                          unsigned Abbrev) {
1094   Record.push_back(N->isDistinct());
1095   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1096   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1097
1098   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1099   Record.clear();
1100 }
1101
1102 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1103                                           const ValueEnumerator &VE,
1104                                           BitstreamWriter &Stream,
1105                                           SmallVectorImpl<uint64_t> &Record,
1106                                           unsigned Abbrev) {
1107   Record.push_back(N->isDistinct());
1108   Record.push_back(N->getTag());
1109   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1110   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1111   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1112
1113   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1114   Record.clear();
1115 }
1116
1117 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1118                                   const ValueEnumerator &VE,
1119                                   BitstreamWriter &Stream,
1120                                   SmallVectorImpl<uint64_t> &Record,
1121                                   unsigned Abbrev) {
1122   Record.push_back(N->isDistinct());
1123   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1124   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1125   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1126   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1127   Record.push_back(N->getLine());
1128   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1129   Record.push_back(N->isLocalToUnit());
1130   Record.push_back(N->isDefinition());
1131   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1132   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1133
1134   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1135   Record.clear();
1136 }
1137
1138 static void WriteDILocalVariable(const DILocalVariable *N,
1139                                  const ValueEnumerator &VE,
1140                                  BitstreamWriter &Stream,
1141                                  SmallVectorImpl<uint64_t> &Record,
1142                                  unsigned Abbrev) {
1143   Record.push_back(N->isDistinct());
1144   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1145   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1146   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1147   Record.push_back(N->getLine());
1148   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1149   Record.push_back(N->getArg());
1150   Record.push_back(N->getFlags());
1151
1152   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1153   Record.clear();
1154 }
1155
1156 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1157                               BitstreamWriter &Stream,
1158                               SmallVectorImpl<uint64_t> &Record,
1159                               unsigned Abbrev) {
1160   Record.reserve(N->getElements().size() + 1);
1161
1162   Record.push_back(N->isDistinct());
1163   Record.append(N->elements_begin(), N->elements_end());
1164
1165   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1166   Record.clear();
1167 }
1168
1169 static void WriteDIObjCProperty(const DIObjCProperty *N,
1170                                 const ValueEnumerator &VE,
1171                                 BitstreamWriter &Stream,
1172                                 SmallVectorImpl<uint64_t> &Record,
1173                                 unsigned Abbrev) {
1174   Record.push_back(N->isDistinct());
1175   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1176   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1177   Record.push_back(N->getLine());
1178   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1179   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1180   Record.push_back(N->getAttributes());
1181   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1182
1183   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1184   Record.clear();
1185 }
1186
1187 static void WriteDIImportedEntity(const DIImportedEntity *N,
1188                                   const ValueEnumerator &VE,
1189                                   BitstreamWriter &Stream,
1190                                   SmallVectorImpl<uint64_t> &Record,
1191                                   unsigned Abbrev) {
1192   Record.push_back(N->isDistinct());
1193   Record.push_back(N->getTag());
1194   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1195   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1196   Record.push_back(N->getLine());
1197   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1198
1199   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1200   Record.clear();
1201 }
1202
1203 static void WriteModuleMetadata(const Module *M,
1204                                 const ValueEnumerator &VE,
1205                                 BitstreamWriter &Stream) {
1206   const auto &MDs = VE.getMDs();
1207   if (MDs.empty() && M->named_metadata_empty())
1208     return;
1209
1210   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1211
1212   unsigned MDSAbbrev = 0;
1213   if (VE.hasMDString()) {
1214     // Abbrev for METADATA_STRING.
1215     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1216     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1218     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1219     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1220   }
1221
1222   // Initialize MDNode abbreviations.
1223 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1224 #include "llvm/IR/Metadata.def"
1225
1226   if (VE.hasDILocation()) {
1227     // Abbrev for METADATA_LOCATION.
1228     //
1229     // Assume the column is usually under 128, and always output the inlined-at
1230     // location (it's never more expensive than building an array size 1).
1231     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1232     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1238     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1239   }
1240
1241   if (VE.hasGenericDINode()) {
1242     // Abbrev for METADATA_GENERIC_DEBUG.
1243     //
1244     // Assume the column is usually under 128, and always output the inlined-at
1245     // location (it's never more expensive than building an array size 1).
1246     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1247     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1254     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1255   }
1256
1257   unsigned NameAbbrev = 0;
1258   if (!M->named_metadata_empty()) {
1259     // Abbrev for METADATA_NAME.
1260     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1261     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1262     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1263     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1264     NameAbbrev = Stream.EmitAbbrev(Abbv);
1265   }
1266
1267   SmallVector<uint64_t, 64> Record;
1268   for (const Metadata *MD : MDs) {
1269     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1270       assert(N->isResolved() && "Expected forward references to be resolved");
1271
1272       switch (N->getMetadataID()) {
1273       default:
1274         llvm_unreachable("Invalid MDNode subclass");
1275 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1276   case Metadata::CLASS##Kind:                                                  \
1277     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1278     continue;
1279 #include "llvm/IR/Metadata.def"
1280       }
1281     }
1282     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1283       WriteValueAsMetadata(MDC, VE, Stream, Record);
1284       continue;
1285     }
1286     const MDString *MDS = cast<MDString>(MD);
1287     // Code: [strchar x N]
1288     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1289
1290     // Emit the finished record.
1291     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1292     Record.clear();
1293   }
1294
1295   // Write named metadata.
1296   for (const NamedMDNode &NMD : M->named_metadata()) {
1297     // Write name.
1298     StringRef Str = NMD.getName();
1299     Record.append(Str.bytes_begin(), Str.bytes_end());
1300     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1301     Record.clear();
1302
1303     // Write named metadata operands.
1304     for (const MDNode *N : NMD.operands())
1305       Record.push_back(VE.getMetadataID(N));
1306     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1307     Record.clear();
1308   }
1309
1310   Stream.ExitBlock();
1311 }
1312
1313 static void WriteFunctionLocalMetadata(const Function &F,
1314                                        const ValueEnumerator &VE,
1315                                        BitstreamWriter &Stream) {
1316   bool StartedMetadataBlock = false;
1317   SmallVector<uint64_t, 64> Record;
1318   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1319       VE.getFunctionLocalMDs();
1320   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1321     assert(MDs[i] && "Expected valid function-local metadata");
1322     if (!StartedMetadataBlock) {
1323       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1324       StartedMetadataBlock = true;
1325     }
1326     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1327   }
1328
1329   if (StartedMetadataBlock)
1330     Stream.ExitBlock();
1331 }
1332
1333 static void WriteMetadataAttachment(const Function &F,
1334                                     const ValueEnumerator &VE,
1335                                     BitstreamWriter &Stream) {
1336   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1337
1338   SmallVector<uint64_t, 64> Record;
1339
1340   // Write metadata attachments
1341   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1342   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1343   F.getAllMetadata(MDs);
1344   if (!MDs.empty()) {
1345     for (const auto &I : MDs) {
1346       Record.push_back(I.first);
1347       Record.push_back(VE.getMetadataID(I.second));
1348     }
1349     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1350     Record.clear();
1351   }
1352
1353   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1354     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1355          I != E; ++I) {
1356       MDs.clear();
1357       I->getAllMetadataOtherThanDebugLoc(MDs);
1358
1359       // If no metadata, ignore instruction.
1360       if (MDs.empty()) continue;
1361
1362       Record.push_back(VE.getInstructionID(I));
1363
1364       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1365         Record.push_back(MDs[i].first);
1366         Record.push_back(VE.getMetadataID(MDs[i].second));
1367       }
1368       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1369       Record.clear();
1370     }
1371
1372   Stream.ExitBlock();
1373 }
1374
1375 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1376   SmallVector<uint64_t, 64> Record;
1377
1378   // Write metadata kinds
1379   // METADATA_KIND - [n x [id, name]]
1380   SmallVector<StringRef, 8> Names;
1381   M->getMDKindNames(Names);
1382
1383   if (Names.empty()) return;
1384
1385   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1386
1387   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1388     Record.push_back(MDKindID);
1389     StringRef KName = Names[MDKindID];
1390     Record.append(KName.begin(), KName.end());
1391
1392     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1393     Record.clear();
1394   }
1395
1396   Stream.ExitBlock();
1397 }
1398
1399 static void WriteOperandBundleTags(const Module *M, BitstreamWriter &Stream) {
1400   // Write metadata kinds
1401   //
1402   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1403   //
1404   // OPERAND_BUNDLE_TAG - [strchr x N]
1405
1406   SmallVector<StringRef, 8> Tags;
1407   M->getOperandBundleTags(Tags);
1408
1409   if (Tags.empty())
1410     return;
1411
1412   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1413
1414   SmallVector<uint64_t, 64> Record;
1415
1416   for (auto Tag : Tags) {
1417     Record.append(Tag.begin(), Tag.end());
1418
1419     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1420     Record.clear();
1421   }
1422
1423   Stream.ExitBlock();
1424 }
1425
1426 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1427   if ((int64_t)V >= 0)
1428     Vals.push_back(V << 1);
1429   else
1430     Vals.push_back((-V << 1) | 1);
1431 }
1432
1433 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1434                            const ValueEnumerator &VE,
1435                            BitstreamWriter &Stream, bool isGlobal) {
1436   if (FirstVal == LastVal) return;
1437
1438   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1439
1440   unsigned AggregateAbbrev = 0;
1441   unsigned String8Abbrev = 0;
1442   unsigned CString7Abbrev = 0;
1443   unsigned CString6Abbrev = 0;
1444   // If this is a constant pool for the module, emit module-specific abbrevs.
1445   if (isGlobal) {
1446     // Abbrev for CST_CODE_AGGREGATE.
1447     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1448     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1451     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1452
1453     // Abbrev for CST_CODE_STRING.
1454     Abbv = new BitCodeAbbrev();
1455     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1458     String8Abbrev = Stream.EmitAbbrev(Abbv);
1459     // Abbrev for CST_CODE_CSTRING.
1460     Abbv = new BitCodeAbbrev();
1461     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1464     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1465     // Abbrev for CST_CODE_CSTRING.
1466     Abbv = new BitCodeAbbrev();
1467     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1470     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1471   }
1472
1473   SmallVector<uint64_t, 64> Record;
1474
1475   const ValueEnumerator::ValueList &Vals = VE.getValues();
1476   Type *LastTy = nullptr;
1477   for (unsigned i = FirstVal; i != LastVal; ++i) {
1478     const Value *V = Vals[i].first;
1479     // If we need to switch types, do so now.
1480     if (V->getType() != LastTy) {
1481       LastTy = V->getType();
1482       Record.push_back(VE.getTypeID(LastTy));
1483       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1484                         CONSTANTS_SETTYPE_ABBREV);
1485       Record.clear();
1486     }
1487
1488     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1489       Record.push_back(unsigned(IA->hasSideEffects()) |
1490                        unsigned(IA->isAlignStack()) << 1 |
1491                        unsigned(IA->getDialect()&1) << 2);
1492
1493       // Add the asm string.
1494       const std::string &AsmStr = IA->getAsmString();
1495       Record.push_back(AsmStr.size());
1496       Record.append(AsmStr.begin(), AsmStr.end());
1497
1498       // Add the constraint string.
1499       const std::string &ConstraintStr = IA->getConstraintString();
1500       Record.push_back(ConstraintStr.size());
1501       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1502       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1503       Record.clear();
1504       continue;
1505     }
1506     const Constant *C = cast<Constant>(V);
1507     unsigned Code = -1U;
1508     unsigned AbbrevToUse = 0;
1509     if (C->isNullValue()) {
1510       Code = bitc::CST_CODE_NULL;
1511     } else if (isa<UndefValue>(C)) {
1512       Code = bitc::CST_CODE_UNDEF;
1513     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1514       if (IV->getBitWidth() <= 64) {
1515         uint64_t V = IV->getSExtValue();
1516         emitSignedInt64(Record, V);
1517         Code = bitc::CST_CODE_INTEGER;
1518         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1519       } else {                             // Wide integers, > 64 bits in size.
1520         // We have an arbitrary precision integer value to write whose
1521         // bit width is > 64. However, in canonical unsigned integer
1522         // format it is likely that the high bits are going to be zero.
1523         // So, we only write the number of active words.
1524         unsigned NWords = IV->getValue().getActiveWords();
1525         const uint64_t *RawWords = IV->getValue().getRawData();
1526         for (unsigned i = 0; i != NWords; ++i) {
1527           emitSignedInt64(Record, RawWords[i]);
1528         }
1529         Code = bitc::CST_CODE_WIDE_INTEGER;
1530       }
1531     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1532       Code = bitc::CST_CODE_FLOAT;
1533       Type *Ty = CFP->getType();
1534       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1535         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1536       } else if (Ty->isX86_FP80Ty()) {
1537         // api needed to prevent premature destruction
1538         // bits are not in the same order as a normal i80 APInt, compensate.
1539         APInt api = CFP->getValueAPF().bitcastToAPInt();
1540         const uint64_t *p = api.getRawData();
1541         Record.push_back((p[1] << 48) | (p[0] >> 16));
1542         Record.push_back(p[0] & 0xffffLL);
1543       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1544         APInt api = CFP->getValueAPF().bitcastToAPInt();
1545         const uint64_t *p = api.getRawData();
1546         Record.push_back(p[0]);
1547         Record.push_back(p[1]);
1548       } else {
1549         assert (0 && "Unknown FP type!");
1550       }
1551     } else if (isa<ConstantDataSequential>(C) &&
1552                cast<ConstantDataSequential>(C)->isString()) {
1553       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1554       // Emit constant strings specially.
1555       unsigned NumElts = Str->getNumElements();
1556       // If this is a null-terminated string, use the denser CSTRING encoding.
1557       if (Str->isCString()) {
1558         Code = bitc::CST_CODE_CSTRING;
1559         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1560       } else {
1561         Code = bitc::CST_CODE_STRING;
1562         AbbrevToUse = String8Abbrev;
1563       }
1564       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1565       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1566       for (unsigned i = 0; i != NumElts; ++i) {
1567         unsigned char V = Str->getElementAsInteger(i);
1568         Record.push_back(V);
1569         isCStr7 &= (V & 128) == 0;
1570         if (isCStrChar6)
1571           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1572       }
1573
1574       if (isCStrChar6)
1575         AbbrevToUse = CString6Abbrev;
1576       else if (isCStr7)
1577         AbbrevToUse = CString7Abbrev;
1578     } else if (const ConstantDataSequential *CDS =
1579                   dyn_cast<ConstantDataSequential>(C)) {
1580       Code = bitc::CST_CODE_DATA;
1581       Type *EltTy = CDS->getType()->getElementType();
1582       if (isa<IntegerType>(EltTy)) {
1583         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1584           Record.push_back(CDS->getElementAsInteger(i));
1585       } else if (EltTy->isFloatTy()) {
1586         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1587           union { float F; uint32_t I; };
1588           F = CDS->getElementAsFloat(i);
1589           Record.push_back(I);
1590         }
1591       } else {
1592         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1593         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1594           union { double F; uint64_t I; };
1595           F = CDS->getElementAsDouble(i);
1596           Record.push_back(I);
1597         }
1598       }
1599     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1600                isa<ConstantVector>(C)) {
1601       Code = bitc::CST_CODE_AGGREGATE;
1602       for (const Value *Op : C->operands())
1603         Record.push_back(VE.getValueID(Op));
1604       AbbrevToUse = AggregateAbbrev;
1605     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1606       switch (CE->getOpcode()) {
1607       default:
1608         if (Instruction::isCast(CE->getOpcode())) {
1609           Code = bitc::CST_CODE_CE_CAST;
1610           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1611           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1612           Record.push_back(VE.getValueID(C->getOperand(0)));
1613           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1614         } else {
1615           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1616           Code = bitc::CST_CODE_CE_BINOP;
1617           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1618           Record.push_back(VE.getValueID(C->getOperand(0)));
1619           Record.push_back(VE.getValueID(C->getOperand(1)));
1620           uint64_t Flags = GetOptimizationFlags(CE);
1621           if (Flags != 0)
1622             Record.push_back(Flags);
1623         }
1624         break;
1625       case Instruction::GetElementPtr: {
1626         Code = bitc::CST_CODE_CE_GEP;
1627         const auto *GO = cast<GEPOperator>(C);
1628         if (GO->isInBounds())
1629           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1630         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1631         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1632           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1633           Record.push_back(VE.getValueID(C->getOperand(i)));
1634         }
1635         break;
1636       }
1637       case Instruction::Select:
1638         Code = bitc::CST_CODE_CE_SELECT;
1639         Record.push_back(VE.getValueID(C->getOperand(0)));
1640         Record.push_back(VE.getValueID(C->getOperand(1)));
1641         Record.push_back(VE.getValueID(C->getOperand(2)));
1642         break;
1643       case Instruction::ExtractElement:
1644         Code = bitc::CST_CODE_CE_EXTRACTELT;
1645         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1646         Record.push_back(VE.getValueID(C->getOperand(0)));
1647         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1648         Record.push_back(VE.getValueID(C->getOperand(1)));
1649         break;
1650       case Instruction::InsertElement:
1651         Code = bitc::CST_CODE_CE_INSERTELT;
1652         Record.push_back(VE.getValueID(C->getOperand(0)));
1653         Record.push_back(VE.getValueID(C->getOperand(1)));
1654         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1655         Record.push_back(VE.getValueID(C->getOperand(2)));
1656         break;
1657       case Instruction::ShuffleVector:
1658         // If the return type and argument types are the same, this is a
1659         // standard shufflevector instruction.  If the types are different,
1660         // then the shuffle is widening or truncating the input vectors, and
1661         // the argument type must also be encoded.
1662         if (C->getType() == C->getOperand(0)->getType()) {
1663           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1664         } else {
1665           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1666           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1667         }
1668         Record.push_back(VE.getValueID(C->getOperand(0)));
1669         Record.push_back(VE.getValueID(C->getOperand(1)));
1670         Record.push_back(VE.getValueID(C->getOperand(2)));
1671         break;
1672       case Instruction::ICmp:
1673       case Instruction::FCmp:
1674         Code = bitc::CST_CODE_CE_CMP;
1675         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1676         Record.push_back(VE.getValueID(C->getOperand(0)));
1677         Record.push_back(VE.getValueID(C->getOperand(1)));
1678         Record.push_back(CE->getPredicate());
1679         break;
1680       }
1681     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1682       Code = bitc::CST_CODE_BLOCKADDRESS;
1683       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1684       Record.push_back(VE.getValueID(BA->getFunction()));
1685       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1686     } else {
1687 #ifndef NDEBUG
1688       C->dump();
1689 #endif
1690       llvm_unreachable("Unknown constant!");
1691     }
1692     Stream.EmitRecord(Code, Record, AbbrevToUse);
1693     Record.clear();
1694   }
1695
1696   Stream.ExitBlock();
1697 }
1698
1699 static void WriteModuleConstants(const ValueEnumerator &VE,
1700                                  BitstreamWriter &Stream) {
1701   const ValueEnumerator::ValueList &Vals = VE.getValues();
1702
1703   // Find the first constant to emit, which is the first non-globalvalue value.
1704   // We know globalvalues have been emitted by WriteModuleInfo.
1705   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1706     if (!isa<GlobalValue>(Vals[i].first)) {
1707       WriteConstants(i, Vals.size(), VE, Stream, true);
1708       return;
1709     }
1710   }
1711 }
1712
1713 /// PushValueAndType - The file has to encode both the value and type id for
1714 /// many values, because we need to know what type to create for forward
1715 /// references.  However, most operands are not forward references, so this type
1716 /// field is not needed.
1717 ///
1718 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1719 /// instruction ID, then it is a forward reference, and it also includes the
1720 /// type ID.  The value ID that is written is encoded relative to the InstID.
1721 static bool PushValueAndType(const Value *V, unsigned InstID,
1722                              SmallVectorImpl<unsigned> &Vals,
1723                              ValueEnumerator &VE) {
1724   unsigned ValID = VE.getValueID(V);
1725   // Make encoding relative to the InstID.
1726   Vals.push_back(InstID - ValID);
1727   if (ValID >= InstID) {
1728     Vals.push_back(VE.getTypeID(V->getType()));
1729     return true;
1730   }
1731   return false;
1732 }
1733
1734 static void WriteOperandBundles(BitstreamWriter &Stream, ImmutableCallSite CS,
1735                                 unsigned InstID, ValueEnumerator &VE) {
1736   SmallVector<unsigned, 64> Record;
1737   LLVMContext &C = CS.getInstruction()->getContext();
1738
1739   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
1740     const auto &Bundle = CS.getOperandBundle(i);
1741     Record.push_back(C.getOperandBundleTagID(Bundle.Tag));
1742
1743     for (auto &Input : Bundle.Inputs)
1744       PushValueAndType(Input, InstID, Record, VE);
1745
1746     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
1747     Record.clear();
1748   }
1749 }
1750
1751 /// pushValue - Like PushValueAndType, but where the type of the value is
1752 /// omitted (perhaps it was already encoded in an earlier operand).
1753 static void pushValue(const Value *V, unsigned InstID,
1754                       SmallVectorImpl<unsigned> &Vals,
1755                       ValueEnumerator &VE) {
1756   unsigned ValID = VE.getValueID(V);
1757   Vals.push_back(InstID - ValID);
1758 }
1759
1760 static void pushValueSigned(const Value *V, unsigned InstID,
1761                             SmallVectorImpl<uint64_t> &Vals,
1762                             ValueEnumerator &VE) {
1763   unsigned ValID = VE.getValueID(V);
1764   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1765   emitSignedInt64(Vals, diff);
1766 }
1767
1768 /// WriteInstruction - Emit an instruction to the specified stream.
1769 static void WriteInstruction(const Instruction &I, unsigned InstID,
1770                              ValueEnumerator &VE, BitstreamWriter &Stream,
1771                              SmallVectorImpl<unsigned> &Vals) {
1772   unsigned Code = 0;
1773   unsigned AbbrevToUse = 0;
1774   VE.setInstructionID(&I);
1775   switch (I.getOpcode()) {
1776   default:
1777     if (Instruction::isCast(I.getOpcode())) {
1778       Code = bitc::FUNC_CODE_INST_CAST;
1779       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1780         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1781       Vals.push_back(VE.getTypeID(I.getType()));
1782       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1783     } else {
1784       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1785       Code = bitc::FUNC_CODE_INST_BINOP;
1786       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1787         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1788       pushValue(I.getOperand(1), InstID, Vals, VE);
1789       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1790       uint64_t Flags = GetOptimizationFlags(&I);
1791       if (Flags != 0) {
1792         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1793           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1794         Vals.push_back(Flags);
1795       }
1796     }
1797     break;
1798
1799   case Instruction::GetElementPtr: {
1800     Code = bitc::FUNC_CODE_INST_GEP;
1801     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1802     auto &GEPInst = cast<GetElementPtrInst>(I);
1803     Vals.push_back(GEPInst.isInBounds());
1804     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1805     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1806       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1807     break;
1808   }
1809   case Instruction::ExtractValue: {
1810     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1811     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1812     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1813     Vals.append(EVI->idx_begin(), EVI->idx_end());
1814     break;
1815   }
1816   case Instruction::InsertValue: {
1817     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1818     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1819     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1820     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1821     Vals.append(IVI->idx_begin(), IVI->idx_end());
1822     break;
1823   }
1824   case Instruction::Select:
1825     Code = bitc::FUNC_CODE_INST_VSELECT;
1826     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1827     pushValue(I.getOperand(2), InstID, Vals, VE);
1828     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1829     break;
1830   case Instruction::ExtractElement:
1831     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1832     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1833     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1834     break;
1835   case Instruction::InsertElement:
1836     Code = bitc::FUNC_CODE_INST_INSERTELT;
1837     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1838     pushValue(I.getOperand(1), InstID, Vals, VE);
1839     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1840     break;
1841   case Instruction::ShuffleVector:
1842     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1843     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1844     pushValue(I.getOperand(1), InstID, Vals, VE);
1845     pushValue(I.getOperand(2), InstID, Vals, VE);
1846     break;
1847   case Instruction::ICmp:
1848   case Instruction::FCmp: {
1849     // compare returning Int1Ty or vector of Int1Ty
1850     Code = bitc::FUNC_CODE_INST_CMP2;
1851     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1852     pushValue(I.getOperand(1), InstID, Vals, VE);
1853     Vals.push_back(cast<CmpInst>(I).getPredicate());
1854     uint64_t Flags = GetOptimizationFlags(&I);
1855     if (Flags != 0)
1856       Vals.push_back(Flags);
1857     break;
1858   }
1859
1860   case Instruction::Ret:
1861     {
1862       Code = bitc::FUNC_CODE_INST_RET;
1863       unsigned NumOperands = I.getNumOperands();
1864       if (NumOperands == 0)
1865         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1866       else if (NumOperands == 1) {
1867         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1868           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1869       } else {
1870         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1871           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1872       }
1873     }
1874     break;
1875   case Instruction::Br:
1876     {
1877       Code = bitc::FUNC_CODE_INST_BR;
1878       const BranchInst &II = cast<BranchInst>(I);
1879       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1880       if (II.isConditional()) {
1881         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1882         pushValue(II.getCondition(), InstID, Vals, VE);
1883       }
1884     }
1885     break;
1886   case Instruction::Switch:
1887     {
1888       Code = bitc::FUNC_CODE_INST_SWITCH;
1889       const SwitchInst &SI = cast<SwitchInst>(I);
1890       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1891       pushValue(SI.getCondition(), InstID, Vals, VE);
1892       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1893       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1894            i != e; ++i) {
1895         Vals.push_back(VE.getValueID(i.getCaseValue()));
1896         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1897       }
1898     }
1899     break;
1900   case Instruction::IndirectBr:
1901     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1902     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1903     // Encode the address operand as relative, but not the basic blocks.
1904     pushValue(I.getOperand(0), InstID, Vals, VE);
1905     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1906       Vals.push_back(VE.getValueID(I.getOperand(i)));
1907     break;
1908
1909   case Instruction::Invoke: {
1910     const InvokeInst *II = cast<InvokeInst>(&I);
1911     const Value *Callee = II->getCalledValue();
1912     FunctionType *FTy = II->getFunctionType();
1913
1914     if (II->hasOperandBundles())
1915       WriteOperandBundles(Stream, II, InstID, VE);
1916
1917     Code = bitc::FUNC_CODE_INST_INVOKE;
1918
1919     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1920     Vals.push_back(II->getCallingConv() | 1 << 13);
1921     Vals.push_back(VE.getValueID(II->getNormalDest()));
1922     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1923     Vals.push_back(VE.getTypeID(FTy));
1924     PushValueAndType(Callee, InstID, Vals, VE);
1925
1926     // Emit value #'s for the fixed parameters.
1927     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1928       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1929
1930     // Emit type/value pairs for varargs params.
1931     if (FTy->isVarArg()) {
1932       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1933            i != e; ++i)
1934         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1935     }
1936     break;
1937   }
1938   case Instruction::Resume:
1939     Code = bitc::FUNC_CODE_INST_RESUME;
1940     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1941     break;
1942   case Instruction::CleanupRet: {
1943     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
1944     const auto &CRI = cast<CleanupReturnInst>(I);
1945     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
1946     if (CRI.hasUnwindDest())
1947       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
1948     break;
1949   }
1950   case Instruction::CatchRet: {
1951     Code = bitc::FUNC_CODE_INST_CATCHRET;
1952     const auto &CRI = cast<CatchReturnInst>(I);
1953     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
1954     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
1955     break;
1956   }
1957   case Instruction::CatchPad: {
1958     Code = bitc::FUNC_CODE_INST_CATCHPAD;
1959     const auto &CPI = cast<CatchPadInst>(I);
1960     Vals.push_back(VE.getValueID(CPI.getNormalDest()));
1961     Vals.push_back(VE.getValueID(CPI.getUnwindDest()));
1962     unsigned NumArgOperands = CPI.getNumArgOperands();
1963     Vals.push_back(NumArgOperands);
1964     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1965       PushValueAndType(CPI.getArgOperand(Op), InstID, Vals, VE);
1966     break;
1967   }
1968   case Instruction::TerminatePad: {
1969     Code = bitc::FUNC_CODE_INST_TERMINATEPAD;
1970     const auto &TPI = cast<TerminatePadInst>(I);
1971     Vals.push_back(TPI.hasUnwindDest());
1972     if (TPI.hasUnwindDest())
1973       Vals.push_back(VE.getValueID(TPI.getUnwindDest()));
1974     unsigned NumArgOperands = TPI.getNumArgOperands();
1975     Vals.push_back(NumArgOperands);
1976     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1977       PushValueAndType(TPI.getArgOperand(Op), InstID, Vals, VE);
1978     break;
1979   }
1980   case Instruction::CleanupPad: {
1981     Code = bitc::FUNC_CODE_INST_CLEANUPPAD;
1982     const auto &CPI = cast<CleanupPadInst>(I);
1983     unsigned NumOperands = CPI.getNumOperands();
1984     Vals.push_back(NumOperands);
1985     for (unsigned Op = 0; Op != NumOperands; ++Op)
1986       PushValueAndType(CPI.getOperand(Op), InstID, Vals, VE);
1987     break;
1988   }
1989   case Instruction::CatchEndPad: {
1990     Code = bitc::FUNC_CODE_INST_CATCHENDPAD;
1991     const auto &CEPI = cast<CatchEndPadInst>(I);
1992     if (CEPI.hasUnwindDest())
1993       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
1994     break;
1995   }
1996   case Instruction::CleanupEndPad: {
1997     Code = bitc::FUNC_CODE_INST_CLEANUPENDPAD;
1998     const auto &CEPI = cast<CleanupEndPadInst>(I);
1999     pushValue(CEPI.getCleanupPad(), InstID, Vals, VE);
2000     if (CEPI.hasUnwindDest())
2001       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
2002     break;
2003   }
2004   case Instruction::Unreachable:
2005     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2006     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2007     break;
2008
2009   case Instruction::PHI: {
2010     const PHINode &PN = cast<PHINode>(I);
2011     Code = bitc::FUNC_CODE_INST_PHI;
2012     // With the newer instruction encoding, forward references could give
2013     // negative valued IDs.  This is most common for PHIs, so we use
2014     // signed VBRs.
2015     SmallVector<uint64_t, 128> Vals64;
2016     Vals64.push_back(VE.getTypeID(PN.getType()));
2017     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2018       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
2019       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2020     }
2021     // Emit a Vals64 vector and exit.
2022     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2023     Vals64.clear();
2024     return;
2025   }
2026
2027   case Instruction::LandingPad: {
2028     const LandingPadInst &LP = cast<LandingPadInst>(I);
2029     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2030     Vals.push_back(VE.getTypeID(LP.getType()));
2031     Vals.push_back(LP.isCleanup());
2032     Vals.push_back(LP.getNumClauses());
2033     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2034       if (LP.isCatch(I))
2035         Vals.push_back(LandingPadInst::Catch);
2036       else
2037         Vals.push_back(LandingPadInst::Filter);
2038       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
2039     }
2040     break;
2041   }
2042
2043   case Instruction::Alloca: {
2044     Code = bitc::FUNC_CODE_INST_ALLOCA;
2045     const AllocaInst &AI = cast<AllocaInst>(I);
2046     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2047     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2048     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2049     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2050     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2051            "not enough bits for maximum alignment");
2052     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2053     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2054     AlignRecord |= 1 << 6;
2055     // Reserve bit 7 for SwiftError flag.
2056     // AlignRecord |= AI.isSwiftError() << 7;
2057     Vals.push_back(AlignRecord);
2058     break;
2059   }
2060
2061   case Instruction::Load:
2062     if (cast<LoadInst>(I).isAtomic()) {
2063       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2064       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2065     } else {
2066       Code = bitc::FUNC_CODE_INST_LOAD;
2067       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2068         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2069     }
2070     Vals.push_back(VE.getTypeID(I.getType()));
2071     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2072     Vals.push_back(cast<LoadInst>(I).isVolatile());
2073     if (cast<LoadInst>(I).isAtomic()) {
2074       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2075       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2076     }
2077     break;
2078   case Instruction::Store:
2079     if (cast<StoreInst>(I).isAtomic())
2080       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2081     else
2082       Code = bitc::FUNC_CODE_INST_STORE;
2083     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2084     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2085     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2086     Vals.push_back(cast<StoreInst>(I).isVolatile());
2087     if (cast<StoreInst>(I).isAtomic()) {
2088       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2089       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2090     }
2091     break;
2092   case Instruction::AtomicCmpXchg:
2093     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2094     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2095     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
2096     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2097     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2098     Vals.push_back(GetEncodedOrdering(
2099                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2100     Vals.push_back(GetEncodedSynchScope(
2101                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2102     Vals.push_back(GetEncodedOrdering(
2103                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2104     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2105     break;
2106   case Instruction::AtomicRMW:
2107     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2108     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2109     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2110     Vals.push_back(GetEncodedRMWOperation(
2111                      cast<AtomicRMWInst>(I).getOperation()));
2112     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2113     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2114     Vals.push_back(GetEncodedSynchScope(
2115                      cast<AtomicRMWInst>(I).getSynchScope()));
2116     break;
2117   case Instruction::Fence:
2118     Code = bitc::FUNC_CODE_INST_FENCE;
2119     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2120     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2121     break;
2122   case Instruction::Call: {
2123     const CallInst &CI = cast<CallInst>(I);
2124     FunctionType *FTy = CI.getFunctionType();
2125
2126     if (CI.hasOperandBundles())
2127       WriteOperandBundles(Stream, &CI, InstID, VE);
2128
2129     Code = bitc::FUNC_CODE_INST_CALL;
2130
2131     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2132     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
2133                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
2134     Vals.push_back(VE.getTypeID(FTy));
2135     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2136
2137     // Emit value #'s for the fixed parameters.
2138     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2139       // Check for labels (can happen with asm labels).
2140       if (FTy->getParamType(i)->isLabelTy())
2141         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2142       else
2143         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2144     }
2145
2146     // Emit type/value pairs for varargs params.
2147     if (FTy->isVarArg()) {
2148       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2149            i != e; ++i)
2150         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2151     }
2152     break;
2153   }
2154   case Instruction::VAArg:
2155     Code = bitc::FUNC_CODE_INST_VAARG;
2156     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2157     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2158     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2159     break;
2160   }
2161
2162   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2163   Vals.clear();
2164 }
2165
2166 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
2167
2168 /// Determine the encoding to use for the given string name and length.
2169 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
2170   bool isChar6 = true;
2171   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
2172     if (isChar6)
2173       isChar6 = BitCodeAbbrevOp::isChar6(*C);
2174     if ((unsigned char)*C & 128)
2175       // don't bother scanning the rest.
2176       return SE_Fixed8;
2177   }
2178   if (isChar6)
2179     return SE_Char6;
2180   else
2181     return SE_Fixed7;
2182 }
2183
2184 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2185 /// BitcodeStartBit and FunctionIndex are only passed for the module-level
2186 /// VST, where we are including a function bitcode index and need to
2187 /// backpatch the VST forward declaration record.
2188 static void WriteValueSymbolTable(
2189     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2190     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2191     uint64_t BitcodeStartBit = 0,
2192     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> *FunctionIndex =
2193         nullptr) {
2194   if (VST.empty()) {
2195     // WriteValueSymbolTableForwardDecl should have returned early as
2196     // well. Ensure this handling remains in sync by asserting that
2197     // the placeholder offset is not set.
2198     assert(VSTOffsetPlaceholder == 0);
2199     return;
2200   }
2201
2202   if (VSTOffsetPlaceholder > 0) {
2203     // Get the offset of the VST we are writing, and backpatch it into
2204     // the VST forward declaration record.
2205     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2206     // The BitcodeStartBit was the stream offset of the actual bitcode
2207     // (e.g. excluding any initial darwin header).
2208     VSTOffset -= BitcodeStartBit;
2209     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2210     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2211   }
2212
2213   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2214
2215   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2216   // records, which are not used in the per-function VSTs.
2217   unsigned FnEntry8BitAbbrev;
2218   unsigned FnEntry7BitAbbrev;
2219   unsigned FnEntry6BitAbbrev;
2220   if (VSTOffsetPlaceholder > 0) {
2221     // 8-bit fixed-width VST_FNENTRY function strings.
2222     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2223     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2228     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2229
2230     // 7-bit fixed width VST_FNENTRY function strings.
2231     Abbv = new BitCodeAbbrev();
2232     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2237     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2238
2239     // 6-bit char6 VST_FNENTRY function strings.
2240     Abbv = new BitCodeAbbrev();
2241     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2246     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2247   }
2248
2249   // FIXME: Set up the abbrev, we know how many values there are!
2250   // FIXME: We know if the type names can use 7-bit ascii.
2251   SmallVector<unsigned, 64> NameVals;
2252
2253   for (const ValueName &Name : VST) {
2254     // Figure out the encoding to use for the name.
2255     StringEncoding Bits =
2256         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2257
2258     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2259     NameVals.push_back(VE.getValueID(Name.getValue()));
2260
2261     Function *F = dyn_cast<Function>(Name.getValue());
2262     if (!F) {
2263       // If value is an alias, need to get the aliased base object to
2264       // see if it is a function.
2265       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2266       if (GA && GA->getBaseObject())
2267         F = dyn_cast<Function>(GA->getBaseObject());
2268     }
2269
2270     // VST_ENTRY:   [valueid, namechar x N]
2271     // VST_FNENTRY: [valueid, funcoffset, namechar x N]
2272     // VST_BBENTRY: [bbid, namechar x N]
2273     unsigned Code;
2274     if (isa<BasicBlock>(Name.getValue())) {
2275       Code = bitc::VST_CODE_BBENTRY;
2276       if (Bits == SE_Char6)
2277         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2278     } else if (F && !F->isDeclaration()) {
2279       // Must be the module-level VST, where we pass in the Index and
2280       // have a VSTOffsetPlaceholder. The function-level VST should not
2281       // contain any Function symbols.
2282       assert(FunctionIndex);
2283       assert(VSTOffsetPlaceholder > 0);
2284
2285       // Save the word offset of the function (from the start of the
2286       // actual bitcode written to the stream).
2287       assert(FunctionIndex->count(F) == 1);
2288       uint64_t BitcodeIndex =
2289           (*FunctionIndex)[F]->bitcodeIndex() - BitcodeStartBit;
2290       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2291       NameVals.push_back(BitcodeIndex / 32);
2292
2293       Code = bitc::VST_CODE_FNENTRY;
2294       AbbrevToUse = FnEntry8BitAbbrev;
2295       if (Bits == SE_Char6)
2296         AbbrevToUse = FnEntry6BitAbbrev;
2297       else if (Bits == SE_Fixed7)
2298         AbbrevToUse = FnEntry7BitAbbrev;
2299     } else {
2300       Code = bitc::VST_CODE_ENTRY;
2301       if (Bits == SE_Char6)
2302         AbbrevToUse = VST_ENTRY_6_ABBREV;
2303       else if (Bits == SE_Fixed7)
2304         AbbrevToUse = VST_ENTRY_7_ABBREV;
2305     }
2306
2307     for (const auto P : Name.getKey()) NameVals.push_back((unsigned char)P);
2308
2309     // Emit the finished record.
2310     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2311     NameVals.clear();
2312   }
2313   Stream.ExitBlock();
2314 }
2315
2316 /// Emit function names and summary offsets for the combined index
2317 /// used by ThinLTO.
2318 static void WriteCombinedValueSymbolTable(const FunctionInfoIndex *Index,
2319                                           BitstreamWriter &Stream) {
2320   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2321
2322   // 8-bit fixed-width VST_COMBINED_FNENTRY function strings.
2323   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2324   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2326   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2328   unsigned FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2329
2330   // 7-bit fixed width VST_COMBINED_FNENTRY function strings.
2331   Abbv = new BitCodeAbbrev();
2332   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2336   unsigned FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2337
2338   // 6-bit char6 VST_COMBINED_FNENTRY function strings.
2339   Abbv = new BitCodeAbbrev();
2340   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_FNENTRY));
2341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2344   unsigned FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2345
2346   // FIXME: We know if the type names can use 7-bit ascii.
2347   SmallVector<unsigned, 64> NameVals;
2348
2349   for (const auto &FII : *Index) {
2350     for (const auto &FI : FII.getValue()) {
2351       NameVals.push_back(FI->bitcodeIndex());
2352
2353       StringRef FuncName = FII.first();
2354
2355       // Figure out the encoding to use for the name.
2356       StringEncoding Bits = getStringEncoding(FuncName.data(), FuncName.size());
2357
2358       // VST_COMBINED_FNENTRY: [funcsumoffset, namechar x N]
2359       unsigned AbbrevToUse = FnEntry8BitAbbrev;
2360       if (Bits == SE_Char6)
2361         AbbrevToUse = FnEntry6BitAbbrev;
2362       else if (Bits == SE_Fixed7)
2363         AbbrevToUse = FnEntry7BitAbbrev;
2364
2365       for (const auto P : FuncName) NameVals.push_back((unsigned char)P);
2366
2367       // Emit the finished record.
2368       Stream.EmitRecord(bitc::VST_CODE_COMBINED_FNENTRY, NameVals, AbbrevToUse);
2369       NameVals.clear();
2370     }
2371   }
2372   Stream.ExitBlock();
2373 }
2374
2375 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2376                          BitstreamWriter &Stream) {
2377   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2378   unsigned Code;
2379   if (isa<BasicBlock>(Order.V))
2380     Code = bitc::USELIST_CODE_BB;
2381   else
2382     Code = bitc::USELIST_CODE_DEFAULT;
2383
2384   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2385   Record.push_back(VE.getValueID(Order.V));
2386   Stream.EmitRecord(Code, Record);
2387 }
2388
2389 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2390                               BitstreamWriter &Stream) {
2391   assert(VE.shouldPreserveUseListOrder() &&
2392          "Expected to be preserving use-list order");
2393
2394   auto hasMore = [&]() {
2395     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2396   };
2397   if (!hasMore())
2398     // Nothing to do.
2399     return;
2400
2401   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2402   while (hasMore()) {
2403     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2404     VE.UseListOrders.pop_back();
2405   }
2406   Stream.ExitBlock();
2407 }
2408
2409 /// \brief Save information for the given function into the function index.
2410 ///
2411 /// At a minimum this saves the bitcode index of the function record that
2412 /// was just written. However, if we are emitting function summary information,
2413 /// for example for ThinLTO, then a \a FunctionSummary object is created
2414 /// to hold the provided summary information.
2415 static void SaveFunctionInfo(
2416     const Function &F,
2417     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2418     unsigned NumInsts, uint64_t BitcodeIndex, bool EmitFunctionSummary) {
2419   std::unique_ptr<FunctionSummary> FuncSummary;
2420   if (EmitFunctionSummary) {
2421     FuncSummary = llvm::make_unique<FunctionSummary>(NumInsts);
2422     FuncSummary->setLocalFunction(F.hasLocalLinkage());
2423   }
2424   FunctionIndex[&F] =
2425       llvm::make_unique<FunctionInfo>(BitcodeIndex, std::move(FuncSummary));
2426 }
2427
2428 /// Emit a function body to the module stream.
2429 static void WriteFunction(
2430     const Function &F, ValueEnumerator &VE, BitstreamWriter &Stream,
2431     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2432     bool EmitFunctionSummary) {
2433   // Save the bitcode index of the start of this function block for recording
2434   // in the VST.
2435   uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
2436
2437   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2438   VE.incorporateFunction(F);
2439
2440   SmallVector<unsigned, 64> Vals;
2441
2442   // Emit the number of basic blocks, so the reader can create them ahead of
2443   // time.
2444   Vals.push_back(VE.getBasicBlocks().size());
2445   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2446   Vals.clear();
2447
2448   // If there are function-local constants, emit them now.
2449   unsigned CstStart, CstEnd;
2450   VE.getFunctionConstantRange(CstStart, CstEnd);
2451   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2452
2453   // If there is function-local metadata, emit it now.
2454   WriteFunctionLocalMetadata(F, VE, Stream);
2455
2456   // Keep a running idea of what the instruction ID is.
2457   unsigned InstID = CstEnd;
2458
2459   bool NeedsMetadataAttachment = F.hasMetadata();
2460
2461   DILocation *LastDL = nullptr;
2462   unsigned NumInsts = 0;
2463
2464   // Finally, emit all the instructions, in order.
2465   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2466     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2467          I != E; ++I) {
2468       WriteInstruction(*I, InstID, VE, Stream, Vals);
2469
2470       if (!isa<DbgInfoIntrinsic>(I)) ++NumInsts;
2471
2472       if (!I->getType()->isVoidTy())
2473         ++InstID;
2474
2475       // If the instruction has metadata, write a metadata attachment later.
2476       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2477
2478       // If the instruction has a debug location, emit it.
2479       DILocation *DL = I->getDebugLoc();
2480       if (!DL)
2481         continue;
2482
2483       if (DL == LastDL) {
2484         // Just repeat the same debug loc as last time.
2485         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2486         continue;
2487       }
2488
2489       Vals.push_back(DL->getLine());
2490       Vals.push_back(DL->getColumn());
2491       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2492       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2493       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2494       Vals.clear();
2495
2496       LastDL = DL;
2497     }
2498
2499   // Emit names for all the instructions etc.
2500   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2501
2502   if (NeedsMetadataAttachment)
2503     WriteMetadataAttachment(F, VE, Stream);
2504   if (VE.shouldPreserveUseListOrder())
2505     WriteUseListBlock(&F, VE, Stream);
2506   VE.purgeFunction();
2507   Stream.ExitBlock();
2508
2509   SaveFunctionInfo(F, FunctionIndex, NumInsts, BitcodeIndex,
2510                    EmitFunctionSummary);
2511 }
2512
2513 // Emit blockinfo, which defines the standard abbreviations etc.
2514 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2515   // We only want to emit block info records for blocks that have multiple
2516   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2517   // Other blocks can define their abbrevs inline.
2518   Stream.EnterBlockInfoBlock(2);
2519
2520   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2521     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2526     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2527                                    Abbv) != VST_ENTRY_8_ABBREV)
2528       llvm_unreachable("Unexpected abbrev ordering!");
2529   }
2530
2531   { // 7-bit fixed width VST_ENTRY strings.
2532     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2533     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2534     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2537     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2538                                    Abbv) != VST_ENTRY_7_ABBREV)
2539       llvm_unreachable("Unexpected abbrev ordering!");
2540   }
2541   { // 6-bit char6 VST_ENTRY strings.
2542     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2543     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2544     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2547     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2548                                    Abbv) != VST_ENTRY_6_ABBREV)
2549       llvm_unreachable("Unexpected abbrev ordering!");
2550   }
2551   { // 6-bit char6 VST_BBENTRY strings.
2552     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2553     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2554     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2555     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2556     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2557     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2558                                    Abbv) != VST_BBENTRY_6_ABBREV)
2559       llvm_unreachable("Unexpected abbrev ordering!");
2560   }
2561
2562
2563
2564   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2565     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2566     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2568                               VE.computeBitsRequiredForTypeIndicies()));
2569     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2570                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2571       llvm_unreachable("Unexpected abbrev ordering!");
2572   }
2573
2574   { // INTEGER abbrev for CONSTANTS_BLOCK.
2575     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2576     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2578     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2579                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2580       llvm_unreachable("Unexpected abbrev ordering!");
2581   }
2582
2583   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2584     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2585     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2586     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2587     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2588                               VE.computeBitsRequiredForTypeIndicies()));
2589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2590
2591     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2592                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2593       llvm_unreachable("Unexpected abbrev ordering!");
2594   }
2595   { // NULL abbrev for CONSTANTS_BLOCK.
2596     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2597     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2598     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2599                                    Abbv) != CONSTANTS_NULL_Abbrev)
2600       llvm_unreachable("Unexpected abbrev ordering!");
2601   }
2602
2603   // FIXME: This should only use space for first class types!
2604
2605   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2606     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2607     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2608     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2609     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2610                               VE.computeBitsRequiredForTypeIndicies()));
2611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2613     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2614                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2615       llvm_unreachable("Unexpected abbrev ordering!");
2616   }
2617   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2618     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2619     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2620     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2621     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2623     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2624                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2625       llvm_unreachable("Unexpected abbrev ordering!");
2626   }
2627   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2628     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2629     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2630     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2634     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2635                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2636       llvm_unreachable("Unexpected abbrev ordering!");
2637   }
2638   { // INST_CAST abbrev for FUNCTION_BLOCK.
2639     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2640     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2642     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2643                               VE.computeBitsRequiredForTypeIndicies()));
2644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2645     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2646                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2647       llvm_unreachable("Unexpected abbrev ordering!");
2648   }
2649
2650   { // INST_RET abbrev for FUNCTION_BLOCK.
2651     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2652     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2653     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2654                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2655       llvm_unreachable("Unexpected abbrev ordering!");
2656   }
2657   { // INST_RET abbrev for FUNCTION_BLOCK.
2658     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2659     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2660     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2661     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2662                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2663       llvm_unreachable("Unexpected abbrev ordering!");
2664   }
2665   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2666     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2667     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2668     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2669                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2670       llvm_unreachable("Unexpected abbrev ordering!");
2671   }
2672   {
2673     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2674     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2677                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2680     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2681         FUNCTION_INST_GEP_ABBREV)
2682       llvm_unreachable("Unexpected abbrev ordering!");
2683   }
2684
2685   Stream.ExitBlock();
2686 }
2687
2688 /// Write the module path strings, currently only used when generating
2689 /// a combined index file.
2690 static void WriteModStrings(const FunctionInfoIndex *I,
2691                             BitstreamWriter &Stream) {
2692   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2693
2694   // TODO: See which abbrev sizes we actually need to emit
2695
2696   // 8-bit fixed-width MST_ENTRY strings.
2697   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2698   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2699   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2700   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2701   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2702   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2703
2704   // 7-bit fixed width MST_ENTRY strings.
2705   Abbv = new BitCodeAbbrev();
2706   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2707   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2708   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2709   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2710   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2711
2712   // 6-bit char6 MST_ENTRY strings.
2713   Abbv = new BitCodeAbbrev();
2714   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2715   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2718   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2719
2720   SmallVector<unsigned, 64> NameVals;
2721   for (const StringMapEntry<uint64_t> &MPSE : I->modPathStringEntries()) {
2722     StringEncoding Bits =
2723         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2724     unsigned AbbrevToUse = Abbrev8Bit;
2725     if (Bits == SE_Char6)
2726       AbbrevToUse = Abbrev6Bit;
2727     else if (Bits == SE_Fixed7)
2728       AbbrevToUse = Abbrev7Bit;
2729
2730     NameVals.push_back(MPSE.getValue());
2731
2732     for (const auto P : MPSE.getKey()) NameVals.push_back((unsigned char)P);
2733
2734     // Emit the finished record.
2735     Stream.EmitRecord(bitc::MST_CODE_ENTRY, NameVals, AbbrevToUse);
2736     NameVals.clear();
2737   }
2738   Stream.ExitBlock();
2739 }
2740
2741 // Helper to emit a single function summary record.
2742 static void WritePerModuleFunctionSummaryRecord(
2743     SmallVector<unsigned, 64> &NameVals, FunctionSummary *FS, unsigned ValueID,
2744     unsigned FSAbbrev, BitstreamWriter &Stream) {
2745   assert(FS);
2746   NameVals.push_back(ValueID);
2747   NameVals.push_back(FS->isLocalFunction());
2748   NameVals.push_back(FS->instCount());
2749
2750   // Emit the finished record.
2751   Stream.EmitRecord(bitc::FS_CODE_PERMODULE_ENTRY, NameVals, FSAbbrev);
2752   NameVals.clear();
2753 }
2754
2755 /// Emit the per-module function summary section alongside the rest of
2756 /// the module's bitcode.
2757 static void WritePerModuleFunctionSummary(
2758     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2759     const Module *M, const ValueEnumerator &VE, BitstreamWriter &Stream) {
2760   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2761
2762   // Abbrev for FS_CODE_PERMODULE_ENTRY.
2763   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2764   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_PERMODULE_ENTRY));
2765   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // valueid
2766   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // islocal
2767   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // instcount
2768   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2769
2770   SmallVector<unsigned, 64> NameVals;
2771   for (auto &I : FunctionIndex) {
2772     // Skip anonymous functions. We will emit a function summary for
2773     // any aliases below.
2774     if (!I.first->hasName()) continue;
2775
2776     WritePerModuleFunctionSummaryRecord(
2777         NameVals, I.second->functionSummary(),
2778         VE.getValueID(M->getValueSymbolTable().lookup(I.first->getName())),
2779         FSAbbrev, Stream);
2780   }
2781
2782   for (const GlobalAlias &A : M->aliases()) {
2783     if (!A.getBaseObject()) continue;
2784     const Function *F = dyn_cast<Function>(A.getBaseObject());
2785     if (!F || F->isDeclaration()) continue;
2786
2787     assert(FunctionIndex.count(F) == 1);
2788     WritePerModuleFunctionSummaryRecord(
2789         NameVals, FunctionIndex[F]->functionSummary(),
2790         VE.getValueID(M->getValueSymbolTable().lookup(A.getName())), FSAbbrev,
2791         Stream);
2792   }
2793
2794   Stream.ExitBlock();
2795 }
2796
2797 /// Emit the combined function summary section into the combined index
2798 /// file.
2799 static void WriteCombinedFunctionSummary(const FunctionInfoIndex *I,
2800                                          BitstreamWriter &Stream) {
2801   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2802
2803   // Abbrev for FS_CODE_COMBINED_ENTRY.
2804   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2805   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_COMBINED_ENTRY));
2806   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // modid
2807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // instcount
2808   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2809
2810   SmallVector<unsigned, 64> NameVals;
2811   for (const auto &FII : *I) {
2812     for (auto &FI : FII.getValue()) {
2813       FunctionSummary *FS = FI->functionSummary();
2814       assert(FS);
2815
2816       NameVals.push_back(I->getModuleId(FS->modulePath()));
2817       NameVals.push_back(FS->instCount());
2818
2819       // Record the starting offset of this summary entry for use
2820       // in the VST entry. Add the current code size since the
2821       // reader will invoke readRecord after the abbrev id read.
2822       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
2823
2824       // Emit the finished record.
2825       Stream.EmitRecord(bitc::FS_CODE_COMBINED_ENTRY, NameVals, FSAbbrev);
2826       NameVals.clear();
2827     }
2828   }
2829
2830   Stream.ExitBlock();
2831 }
2832
2833 /// WriteModule - Emit the specified module to the bitstream.
2834 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2835                         bool ShouldPreserveUseListOrder,
2836                         uint64_t BitcodeStartBit, bool EmitFunctionSummary) {
2837   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2838
2839   SmallVector<unsigned, 1> Vals;
2840   unsigned CurVersion = 1;
2841   Vals.push_back(CurVersion);
2842   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2843
2844   // Analyze the module, enumerating globals, functions, etc.
2845   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2846
2847   // Emit blockinfo, which defines the standard abbreviations etc.
2848   WriteBlockInfo(VE, Stream);
2849
2850   // Emit information about attribute groups.
2851   WriteAttributeGroupTable(VE, Stream);
2852
2853   // Emit information about parameter attributes.
2854   WriteAttributeTable(VE, Stream);
2855
2856   // Emit information describing all of the types in the module.
2857   WriteTypeTable(VE, Stream);
2858
2859   writeComdats(VE, Stream);
2860
2861   // Emit top-level description of module, including target triple, inline asm,
2862   // descriptors for global variables, and function prototype info.
2863   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
2864
2865   // Emit constants.
2866   WriteModuleConstants(VE, Stream);
2867
2868   // Emit metadata.
2869   WriteModuleMetadata(M, VE, Stream);
2870
2871   // Emit metadata.
2872   WriteModuleMetadataStore(M, Stream);
2873
2874   // Emit module-level use-lists.
2875   if (VE.shouldPreserveUseListOrder())
2876     WriteUseListBlock(nullptr, VE, Stream);
2877
2878   WriteOperandBundleTags(M, Stream);
2879
2880   // Emit function bodies.
2881   DenseMap<const Function *, std::unique_ptr<FunctionInfo>> FunctionIndex;
2882   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2883     if (!F->isDeclaration())
2884       WriteFunction(*F, VE, Stream, FunctionIndex, EmitFunctionSummary);
2885
2886   // Need to write after the above call to WriteFunction which populates
2887   // the summary information in the index.
2888   if (EmitFunctionSummary)
2889     WritePerModuleFunctionSummary(FunctionIndex, M, VE, Stream);
2890
2891   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
2892                         VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
2893
2894   Stream.ExitBlock();
2895 }
2896
2897 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2898 /// header and trailer to make it compatible with the system archiver.  To do
2899 /// this we emit the following header, and then emit a trailer that pads the
2900 /// file out to be a multiple of 16 bytes.
2901 ///
2902 /// struct bc_header {
2903 ///   uint32_t Magic;         // 0x0B17C0DE
2904 ///   uint32_t Version;       // Version, currently always 0.
2905 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2906 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2907 ///   uint32_t CPUType;       // CPU specifier.
2908 ///   ... potentially more later ...
2909 /// };
2910 enum {
2911   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2912   DarwinBCHeaderSize = 5*4
2913 };
2914
2915 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2916                                uint32_t &Position) {
2917   support::endian::write32le(&Buffer[Position], Value);
2918   Position += 4;
2919 }
2920
2921 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2922                                          const Triple &TT) {
2923   unsigned CPUType = ~0U;
2924
2925   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2926   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2927   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2928   // specific constants here because they are implicitly part of the Darwin ABI.
2929   enum {
2930     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2931     DARWIN_CPU_TYPE_X86        = 7,
2932     DARWIN_CPU_TYPE_ARM        = 12,
2933     DARWIN_CPU_TYPE_POWERPC    = 18
2934   };
2935
2936   Triple::ArchType Arch = TT.getArch();
2937   if (Arch == Triple::x86_64)
2938     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2939   else if (Arch == Triple::x86)
2940     CPUType = DARWIN_CPU_TYPE_X86;
2941   else if (Arch == Triple::ppc)
2942     CPUType = DARWIN_CPU_TYPE_POWERPC;
2943   else if (Arch == Triple::ppc64)
2944     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2945   else if (Arch == Triple::arm || Arch == Triple::thumb)
2946     CPUType = DARWIN_CPU_TYPE_ARM;
2947
2948   // Traditional Bitcode starts after header.
2949   assert(Buffer.size() >= DarwinBCHeaderSize &&
2950          "Expected header size to be reserved");
2951   unsigned BCOffset = DarwinBCHeaderSize;
2952   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2953
2954   // Write the magic and version.
2955   unsigned Position = 0;
2956   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2957   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2958   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2959   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2960   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2961
2962   // If the file is not a multiple of 16 bytes, insert dummy padding.
2963   while (Buffer.size() & 15)
2964     Buffer.push_back(0);
2965 }
2966
2967 /// Helper to write the header common to all bitcode files.
2968 static void WriteBitcodeHeader(BitstreamWriter &Stream) {
2969   // Emit the file header.
2970   Stream.Emit((unsigned)'B', 8);
2971   Stream.Emit((unsigned)'C', 8);
2972   Stream.Emit(0x0, 4);
2973   Stream.Emit(0xC, 4);
2974   Stream.Emit(0xE, 4);
2975   Stream.Emit(0xD, 4);
2976 }
2977
2978 /// WriteBitcodeToFile - Write the specified module to the specified output
2979 /// stream.
2980 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2981                               bool ShouldPreserveUseListOrder,
2982                               bool EmitFunctionSummary) {
2983   SmallVector<char, 0> Buffer;
2984   Buffer.reserve(256*1024);
2985
2986   // If this is darwin or another generic macho target, reserve space for the
2987   // header.
2988   Triple TT(M->getTargetTriple());
2989   if (TT.isOSDarwin())
2990     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2991
2992   // Emit the module into the buffer.
2993   {
2994     BitstreamWriter Stream(Buffer);
2995     // Save the start bit of the actual bitcode, in case there is space
2996     // saved at the start for the darwin header above. The reader stream
2997     // will start at the bitcode, and we need the offset of the VST
2998     // to line up.
2999     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
3000
3001     // Emit the file header.
3002     WriteBitcodeHeader(Stream);
3003
3004     // Emit the module.
3005     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit,
3006                 EmitFunctionSummary);
3007   }
3008
3009   if (TT.isOSDarwin())
3010     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
3011
3012   // Write the generated bitstream to "Out".
3013   Out.write((char*)&Buffer.front(), Buffer.size());
3014 }
3015
3016 // Write the specified function summary index to the given raw output stream,
3017 // where it will be written in a new bitcode block. This is used when
3018 // writing the combined index file for ThinLTO.
3019 void llvm::WriteFunctionSummaryToFile(const FunctionInfoIndex *Index,
3020                                       raw_ostream &Out) {
3021   SmallVector<char, 0> Buffer;
3022   Buffer.reserve(256 * 1024);
3023
3024   BitstreamWriter Stream(Buffer);
3025
3026   // Emit the bitcode header.
3027   WriteBitcodeHeader(Stream);
3028
3029   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3030
3031   SmallVector<unsigned, 1> Vals;
3032   unsigned CurVersion = 1;
3033   Vals.push_back(CurVersion);
3034   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3035
3036   // Write the module paths in the combined index.
3037   WriteModStrings(Index, Stream);
3038
3039   // Write the function summary combined index records.
3040   WriteCombinedFunctionSummary(Index, Stream);
3041
3042   // Need a special VST writer for the combined index (we don't have a
3043   // real VST and real values when this is invoked).
3044   WriteCombinedValueSymbolTable(Index, Stream);
3045
3046   Stream.ExitBlock();
3047
3048   Out.write((char *)&Buffer.front(), Buffer.size());
3049 }