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())
 587     return 0;
 588
 589   // Write a placeholder value in for the offset of the real VST,
 590   // which is written after the function blocks so that it can include
 591   // the offset of each function. The placeholder offset will be
 592   // updated when the real VST is written.
 593   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 594   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
 595   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
 596   // hold the real VST offset. Must use fixed instead of VBR as we don't
 597   // know how many VBR chunks to reserve ahead of time.
 598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
 599   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
 600
 601   // Emit the placeholder
 602   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
 603   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
 604
 605   // Compute and return the bit offset to the placeholder, which will be
 606   // patched when the real VST is written. We can simply subtract the 32-bit
 607   // fixed size from the current bit number to get the location to backpatch.
 608   return Stream.GetCurrentBitNo() - 32;
 609 }
 610
 611 /// Emit top-level description of module, including target triple, inline asm,
 612 /// descriptors for global variables, and function prototype info.
 613 /// Returns the bit offset to backpatch with the location of the real VST.
 614 static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 615                                 BitstreamWriter &Stream) {
 616   // Emit various pieces of data attached to a module.
 617   if (!M->getTargetTriple().empty())
 618     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 619                       0/*TODO*/, Stream);
 620   const std::string &DL = M->getDataLayoutStr();
 621   if (!DL.empty())
 622     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 623   if (!M->getModuleInlineAsm().empty())
 624     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 625                       0/*TODO*/, Stream);
 626
 627   // Emit information about sections and GC, computing how many there are. Also
 628   // compute the maximum alignment value.
 629   std::map<std::string, unsigned> SectionMap;
 630   std::map<std::string, unsigned> GCMap;
 631   unsigned MaxAlignment = 0;
 632   unsigned MaxGlobalType = 0;
 633   for (const GlobalValue &GV : M->globals()) {
 634     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 635     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 636     if (GV.hasSection()) {
 637       // Give section names unique ID's.
 638       unsigned &Entry = SectionMap[GV.getSection()];
 639       if (!Entry) {
 640         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 641                           0/*TODO*/, Stream);
 642         Entry = SectionMap.size();
 643       }
 644     }
 645   }
 646   for (const Function &F : *M) {
 647     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 648     if (F.hasSection()) {
 649       // Give section names unique ID's.
 650       unsigned &Entry = SectionMap[F.getSection()];
 651       if (!Entry) {
 652         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 653                           0/*TODO*/, Stream);
 654         Entry = SectionMap.size();
 655       }
 656     }
 657     if (F.hasGC()) {
 658       // Same for GC names.
 659       unsigned &Entry = GCMap[F.getGC()];
 660       if (!Entry) {
 661         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 662                           0/*TODO*/, Stream);
 663         Entry = GCMap.size();
 664       }
 665     }
 666   }
 667
 668   // Emit abbrev for globals, now that we know # sections and max alignment.
 669   unsigned SimpleGVarAbbrev = 0;
 670   if (!M->global_empty()) {
 671     // Add an abbrev for common globals with no visibility or thread localness.
 672     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 673     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 674     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 675                               Log2_32_Ceil(MaxGlobalType+1)));
 676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 677                                                            //| explicitType << 1
 678                                                            //| constant
 679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 681     if (MaxAlignment == 0)                                 // Alignment.
 682       Abbv->Add(BitCodeAbbrevOp(0));
 683     else {
 684       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 685       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 686                                Log2_32_Ceil(MaxEncAlignment+1)));
 687     }
 688     if (SectionMap.empty())                                    // Section.
 689       Abbv->Add(BitCodeAbbrevOp(0));
 690     else
 691       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 692                                Log2_32_Ceil(SectionMap.size()+1)));
 693     // Don't bother emitting vis + thread local.
 694     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 695   }
 696
 697   // Emit the global variable information.
 698   SmallVector<unsigned, 64> Vals;
 699   for (const GlobalVariable &GV : M->globals()) {
 700     unsigned AbbrevToUse = 0;
 701
 702     // GLOBALVAR: [type, isconst, initid,
 703     //             linkage, alignment, section, visibility, threadlocal,
 704     //             unnamed_addr, externally_initialized, dllstorageclass,
 705     //             comdat]
 706     Vals.push_back(VE.getTypeID(GV.getValueType()));
 707     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 708     Vals.push_back(GV.isDeclaration() ? 0 :
 709                    (VE.getValueID(GV.getInitializer()) + 1));
 710     Vals.push_back(getEncodedLinkage(GV));
 711     Vals.push_back(Log2_32(GV.getAlignment())+1);
 712     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 713     if (GV.isThreadLocal() ||
 714         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 715         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 716         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 717         GV.hasComdat()) {
 718       Vals.push_back(getEncodedVisibility(GV));
 719       Vals.push_back(getEncodedThreadLocalMode(GV));
 720       Vals.push_back(GV.hasUnnamedAddr());
 721       Vals.push_back(GV.isExternallyInitialized());
 722       Vals.push_back(getEncodedDLLStorageClass(GV));
 723       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 724     } else {
 725       AbbrevToUse = SimpleGVarAbbrev;
 726     }
 727
 728     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 729     Vals.clear();
 730   }
 731
 732   // Emit the function proto information.
 733   for (const Function &F : *M) {
 734     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 735     //             section, visibility, gc, unnamed_addr, prologuedata,
 736     //             dllstorageclass, comdat, prefixdata, personalityfn]
 737     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 738     Vals.push_back(F.getCallingConv());
 739     Vals.push_back(F.isDeclaration());
 740     Vals.push_back(getEncodedLinkage(F));
 741     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 742     Vals.push_back(Log2_32(F.getAlignment())+1);
 743     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 744     Vals.push_back(getEncodedVisibility(F));
 745     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 746     Vals.push_back(F.hasUnnamedAddr());
 747     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 748                                        : 0);
 749     Vals.push_back(getEncodedDLLStorageClass(F));
 750     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 751     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 752                                      : 0);
 753     Vals.push_back(
 754         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
 755
 756     unsigned AbbrevToUse = 0;
 757     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 758     Vals.clear();
 759   }
 760
 761   // Emit the alias information.
 762   for (const GlobalAlias &A : M->aliases()) {
 763     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 764     Vals.push_back(VE.getTypeID(A.getValueType()));
 765     Vals.push_back(A.getType()->getAddressSpace());
 766     Vals.push_back(VE.getValueID(A.getAliasee()));
 767     Vals.push_back(getEncodedLinkage(A));
 768     Vals.push_back(getEncodedVisibility(A));
 769     Vals.push_back(getEncodedDLLStorageClass(A));
 770     Vals.push_back(getEncodedThreadLocalMode(A));
 771     Vals.push_back(A.hasUnnamedAddr());
 772     unsigned AbbrevToUse = 0;
 773     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 774     Vals.clear();
 775   }
 776
 777   uint64_t VSTOffsetPlaceholder =
 778       WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
 779   return VSTOffsetPlaceholder;
 780 }
 781
 782 static uint64_t GetOptimizationFlags(const Value *V) {
 783   uint64_t Flags = 0;
 784
 785   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 786     if (OBO->hasNoSignedWrap())
 787       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 788     if (OBO->hasNoUnsignedWrap())
 789       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 790   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 791     if (PEO->isExact())
 792       Flags |= 1 << bitc::PEO_EXACT;
 793   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 794     if (FPMO->hasUnsafeAlgebra())
 795       Flags |= FastMathFlags::UnsafeAlgebra;
 796     if (FPMO->hasNoNaNs())
 797       Flags |= FastMathFlags::NoNaNs;
 798     if (FPMO->hasNoInfs())
 799       Flags |= FastMathFlags::NoInfs;
 800     if (FPMO->hasNoSignedZeros())
 801       Flags |= FastMathFlags::NoSignedZeros;
 802     if (FPMO->hasAllowReciprocal())
 803       Flags |= FastMathFlags::AllowReciprocal;
 804   }
 805
 806   return Flags;
 807 }
 808
 809 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 810                                  const ValueEnumerator &VE,
 811                                  BitstreamWriter &Stream,
 812                                  SmallVectorImpl<uint64_t> &Record) {
 813   // Mimic an MDNode with a value as one operand.
 814   Value *V = MD->getValue();
 815   Record.push_back(VE.getTypeID(V->getType()));
 816   Record.push_back(VE.getValueID(V));
 817   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 818   Record.clear();
 819 }
 820
 821 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 822                          BitstreamWriter &Stream,
 823                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 824   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 825     Metadata *MD = N->getOperand(i);
 826     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 827            "Unexpected function-local metadata");
 828     Record.push_back(VE.getMetadataOrNullID(MD));
 829   }
 830   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 831                                     : bitc::METADATA_NODE,
 832                     Record, Abbrev);
 833   Record.clear();
 834 }
 835
 836 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 837                             BitstreamWriter &Stream,
 838                             SmallVectorImpl<uint64_t> &Record,
 839                             unsigned Abbrev) {
 840   Record.push_back(N->isDistinct());
 841   Record.push_back(N->getLine());
 842   Record.push_back(N->getColumn());
 843   Record.push_back(VE.getMetadataID(N->getScope()));
 844   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 845
 846   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 847   Record.clear();
 848 }
 849
 850 static void WriteGenericDINode(const GenericDINode *N,
 851                                const ValueEnumerator &VE,
 852                                BitstreamWriter &Stream,
 853                                SmallVectorImpl<uint64_t> &Record,
 854                                unsigned Abbrev) {
 855   Record.push_back(N->isDistinct());
 856   Record.push_back(N->getTag());
 857   Record.push_back(0); // Per-tag version field; unused for now.
 858
 859   for (auto &I : N->operands())
 860     Record.push_back(VE.getMetadataOrNullID(I));
 861
 862   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 863   Record.clear();
 864 }
 865
 866 static uint64_t rotateSign(int64_t I) {
 867   uint64_t U = I;
 868   return I < 0 ? ~(U << 1) : U << 1;
 869 }
 870
 871 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 872                             BitstreamWriter &Stream,
 873                             SmallVectorImpl<uint64_t> &Record,
 874                             unsigned Abbrev) {
 875   Record.push_back(N->isDistinct());
 876   Record.push_back(N->getCount());
 877   Record.push_back(rotateSign(N->getLowerBound()));
 878
 879   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 880   Record.clear();
 881 }
 882
 883 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 884                               BitstreamWriter &Stream,
 885                               SmallVectorImpl<uint64_t> &Record,
 886                               unsigned Abbrev) {
 887   Record.push_back(N->isDistinct());
 888   Record.push_back(rotateSign(N->getValue()));
 889   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 890
 891   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 892   Record.clear();
 893 }
 894
 895 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 896                              BitstreamWriter &Stream,
 897                              SmallVectorImpl<uint64_t> &Record,
 898                              unsigned Abbrev) {
 899   Record.push_back(N->isDistinct());
 900   Record.push_back(N->getTag());
 901   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 902   Record.push_back(N->getSizeInBits());
 903   Record.push_back(N->getAlignInBits());
 904   Record.push_back(N->getEncoding());
 905
 906   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 907   Record.clear();
 908 }
 909
 910 static void WriteDIDerivedType(const DIDerivedType *N,
 911                                const ValueEnumerator &VE,
 912                                BitstreamWriter &Stream,
 913                                SmallVectorImpl<uint64_t> &Record,
 914                                unsigned Abbrev) {
 915   Record.push_back(N->isDistinct());
 916   Record.push_back(N->getTag());
 917   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 918   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 919   Record.push_back(N->getLine());
 920   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 921   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 922   Record.push_back(N->getSizeInBits());
 923   Record.push_back(N->getAlignInBits());
 924   Record.push_back(N->getOffsetInBits());
 925   Record.push_back(N->getFlags());
 926   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 927
 928   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 929   Record.clear();
 930 }
 931
 932 static void WriteDICompositeType(const DICompositeType *N,
 933                                  const ValueEnumerator &VE,
 934                                  BitstreamWriter &Stream,
 935                                  SmallVectorImpl<uint64_t> &Record,
 936                                  unsigned Abbrev) {
 937   Record.push_back(N->isDistinct());
 938   Record.push_back(N->getTag());
 939   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 940   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 941   Record.push_back(N->getLine());
 942   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 943   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 944   Record.push_back(N->getSizeInBits());
 945   Record.push_back(N->getAlignInBits());
 946   Record.push_back(N->getOffsetInBits());
 947   Record.push_back(N->getFlags());
 948   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 949   Record.push_back(N->getRuntimeLang());
 950   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 951   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 952   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 953
 954   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 955   Record.clear();
 956 }
 957
 958 static void WriteDISubroutineType(const DISubroutineType *N,
 959                                   const ValueEnumerator &VE,
 960                                   BitstreamWriter &Stream,
 961                                   SmallVectorImpl<uint64_t> &Record,
 962                                   unsigned Abbrev) {
 963   Record.push_back(N->isDistinct());
 964   Record.push_back(N->getFlags());
 965   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 966
 967   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 968   Record.clear();
 969 }
 970
 971 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 972                         BitstreamWriter &Stream,
 973                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 974   Record.push_back(N->isDistinct());
 975   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 976   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 977
 978   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 979   Record.clear();
 980 }
 981
 982 static void WriteDICompileUnit(const DICompileUnit *N,
 983                                const ValueEnumerator &VE,
 984                                BitstreamWriter &Stream,
 985                                SmallVectorImpl<uint64_t> &Record,
 986                                unsigned Abbrev) {
 987   assert(N->isDistinct() && "Expected distinct compile units");
 988   Record.push_back(/* IsDistinct */ true);
 989   Record.push_back(N->getSourceLanguage());
 990   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 991   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 992   Record.push_back(N->isOptimized());
 993   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 994   Record.push_back(N->getRuntimeVersion());
 995   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 996   Record.push_back(N->getEmissionKind());
 997   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 998   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 999   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
1000   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1001   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1002   Record.push_back(N->getDWOId());
1003
1004   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1005   Record.clear();
1006 }
1007
1008 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1009                               BitstreamWriter &Stream,
1010                               SmallVectorImpl<uint64_t> &Record,
1011                               unsigned Abbrev) {
1012   Record.push_back(N->isDistinct());
1013   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1014   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1015   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1016   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1017   Record.push_back(N->getLine());
1018   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1019   Record.push_back(N->isLocalToUnit());
1020   Record.push_back(N->isDefinition());
1021   Record.push_back(N->getScopeLine());
1022   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1023   Record.push_back(N->getVirtuality());
1024   Record.push_back(N->getVirtualIndex());
1025   Record.push_back(N->getFlags());
1026   Record.push_back(N->isOptimized());
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 (const BasicBlock &BB : F)
1354     for (const Instruction &I : BB) {
1355       MDs.clear();
1356       I.getAllMetadataOtherThanDebugLoc(MDs);
1357
1358       // If no metadata, ignore instruction.
1359       if (MDs.empty()) continue;
1360
1361       Record.push_back(VE.getInstructionID(&I));
1362
1363       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1364         Record.push_back(MDs[i].first);
1365         Record.push_back(VE.getMetadataID(MDs[i].second));
1366       }
1367       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1368       Record.clear();
1369     }
1370
1371   Stream.ExitBlock();
1372 }
1373
1374 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1375   SmallVector<uint64_t, 64> Record;
1376
1377   // Write metadata kinds
1378   // METADATA_KIND - [n x [id, name]]
1379   SmallVector<StringRef, 8> Names;
1380   M->getMDKindNames(Names);
1381
1382   if (Names.empty()) return;
1383
1384   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1385
1386   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1387     Record.push_back(MDKindID);
1388     StringRef KName = Names[MDKindID];
1389     Record.append(KName.begin(), KName.end());
1390
1391     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1392     Record.clear();
1393   }
1394
1395   Stream.ExitBlock();
1396 }
1397
1398 static void WriteOperandBundleTags(const Module *M, BitstreamWriter &Stream) {
1399   // Write metadata kinds
1400   //
1401   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
1402   //
1403   // OPERAND_BUNDLE_TAG - [strchr x N]
1404
1405   SmallVector<StringRef, 8> Tags;
1406   M->getOperandBundleTags(Tags);
1407
1408   if (Tags.empty())
1409     return;
1410
1411   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
1412
1413   SmallVector<uint64_t, 64> Record;
1414
1415   for (auto Tag : Tags) {
1416     Record.append(Tag.begin(), Tag.end());
1417
1418     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
1419     Record.clear();
1420   }
1421
1422   Stream.ExitBlock();
1423 }
1424
1425 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1426   if ((int64_t)V >= 0)
1427     Vals.push_back(V << 1);
1428   else
1429     Vals.push_back((-V << 1) | 1);
1430 }
1431
1432 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1433                            const ValueEnumerator &VE,
1434                            BitstreamWriter &Stream, bool isGlobal) {
1435   if (FirstVal == LastVal) return;
1436
1437   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1438
1439   unsigned AggregateAbbrev = 0;
1440   unsigned String8Abbrev = 0;
1441   unsigned CString7Abbrev = 0;
1442   unsigned CString6Abbrev = 0;
1443   // If this is a constant pool for the module, emit module-specific abbrevs.
1444   if (isGlobal) {
1445     // Abbrev for CST_CODE_AGGREGATE.
1446     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1447     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1450     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1451
1452     // Abbrev for CST_CODE_STRING.
1453     Abbv = new BitCodeAbbrev();
1454     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1457     String8Abbrev = Stream.EmitAbbrev(Abbv);
1458     // Abbrev for CST_CODE_CSTRING.
1459     Abbv = new BitCodeAbbrev();
1460     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1463     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1464     // Abbrev for CST_CODE_CSTRING.
1465     Abbv = new BitCodeAbbrev();
1466     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1469     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1470   }
1471
1472   SmallVector<uint64_t, 64> Record;
1473
1474   const ValueEnumerator::ValueList &Vals = VE.getValues();
1475   Type *LastTy = nullptr;
1476   for (unsigned i = FirstVal; i != LastVal; ++i) {
1477     const Value *V = Vals[i].first;
1478     // If we need to switch types, do so now.
1479     if (V->getType() != LastTy) {
1480       LastTy = V->getType();
1481       Record.push_back(VE.getTypeID(LastTy));
1482       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1483                         CONSTANTS_SETTYPE_ABBREV);
1484       Record.clear();
1485     }
1486
1487     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1488       Record.push_back(unsigned(IA->hasSideEffects()) |
1489                        unsigned(IA->isAlignStack()) << 1 |
1490                        unsigned(IA->getDialect()&1) << 2);
1491
1492       // Add the asm string.
1493       const std::string &AsmStr = IA->getAsmString();
1494       Record.push_back(AsmStr.size());
1495       Record.append(AsmStr.begin(), AsmStr.end());
1496
1497       // Add the constraint string.
1498       const std::string &ConstraintStr = IA->getConstraintString();
1499       Record.push_back(ConstraintStr.size());
1500       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1501       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1502       Record.clear();
1503       continue;
1504     }
1505     const Constant *C = cast<Constant>(V);
1506     unsigned Code = -1U;
1507     unsigned AbbrevToUse = 0;
1508     if (C->isNullValue()) {
1509       Code = bitc::CST_CODE_NULL;
1510     } else if (isa<UndefValue>(C)) {
1511       Code = bitc::CST_CODE_UNDEF;
1512     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1513       if (IV->getBitWidth() <= 64) {
1514         uint64_t V = IV->getSExtValue();
1515         emitSignedInt64(Record, V);
1516         Code = bitc::CST_CODE_INTEGER;
1517         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1518       } else {                             // Wide integers, > 64 bits in size.
1519         // We have an arbitrary precision integer value to write whose
1520         // bit width is > 64. However, in canonical unsigned integer
1521         // format it is likely that the high bits are going to be zero.
1522         // So, we only write the number of active words.
1523         unsigned NWords = IV->getValue().getActiveWords();
1524         const uint64_t *RawWords = IV->getValue().getRawData();
1525         for (unsigned i = 0; i != NWords; ++i) {
1526           emitSignedInt64(Record, RawWords[i]);
1527         }
1528         Code = bitc::CST_CODE_WIDE_INTEGER;
1529       }
1530     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1531       Code = bitc::CST_CODE_FLOAT;
1532       Type *Ty = CFP->getType();
1533       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1534         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1535       } else if (Ty->isX86_FP80Ty()) {
1536         // api needed to prevent premature destruction
1537         // bits are not in the same order as a normal i80 APInt, compensate.
1538         APInt api = CFP->getValueAPF().bitcastToAPInt();
1539         const uint64_t *p = api.getRawData();
1540         Record.push_back((p[1] << 48) | (p[0] >> 16));
1541         Record.push_back(p[0] & 0xffffLL);
1542       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1543         APInt api = CFP->getValueAPF().bitcastToAPInt();
1544         const uint64_t *p = api.getRawData();
1545         Record.push_back(p[0]);
1546         Record.push_back(p[1]);
1547       } else {
1548         assert (0 && "Unknown FP type!");
1549       }
1550     } else if (isa<ConstantDataSequential>(C) &&
1551                cast<ConstantDataSequential>(C)->isString()) {
1552       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1553       // Emit constant strings specially.
1554       unsigned NumElts = Str->getNumElements();
1555       // If this is a null-terminated string, use the denser CSTRING encoding.
1556       if (Str->isCString()) {
1557         Code = bitc::CST_CODE_CSTRING;
1558         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1559       } else {
1560         Code = bitc::CST_CODE_STRING;
1561         AbbrevToUse = String8Abbrev;
1562       }
1563       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1564       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1565       for (unsigned i = 0; i != NumElts; ++i) {
1566         unsigned char V = Str->getElementAsInteger(i);
1567         Record.push_back(V);
1568         isCStr7 &= (V & 128) == 0;
1569         if (isCStrChar6)
1570           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1571       }
1572
1573       if (isCStrChar6)
1574         AbbrevToUse = CString6Abbrev;
1575       else if (isCStr7)
1576         AbbrevToUse = CString7Abbrev;
1577     } else if (const ConstantDataSequential *CDS =
1578                   dyn_cast<ConstantDataSequential>(C)) {
1579       Code = bitc::CST_CODE_DATA;
1580       Type *EltTy = CDS->getType()->getElementType();
1581       if (isa<IntegerType>(EltTy)) {
1582         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1583           Record.push_back(CDS->getElementAsInteger(i));
1584       } else if (EltTy->isFloatTy()) {
1585         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1586           union { float F; uint32_t I; };
1587           F = CDS->getElementAsFloat(i);
1588           Record.push_back(I);
1589         }
1590       } else {
1591         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1592         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1593           union { double F; uint64_t I; };
1594           F = CDS->getElementAsDouble(i);
1595           Record.push_back(I);
1596         }
1597       }
1598     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1599                isa<ConstantVector>(C)) {
1600       Code = bitc::CST_CODE_AGGREGATE;
1601       for (const Value *Op : C->operands())
1602         Record.push_back(VE.getValueID(Op));
1603       AbbrevToUse = AggregateAbbrev;
1604     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1605       switch (CE->getOpcode()) {
1606       default:
1607         if (Instruction::isCast(CE->getOpcode())) {
1608           Code = bitc::CST_CODE_CE_CAST;
1609           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1610           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1611           Record.push_back(VE.getValueID(C->getOperand(0)));
1612           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1613         } else {
1614           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1615           Code = bitc::CST_CODE_CE_BINOP;
1616           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1617           Record.push_back(VE.getValueID(C->getOperand(0)));
1618           Record.push_back(VE.getValueID(C->getOperand(1)));
1619           uint64_t Flags = GetOptimizationFlags(CE);
1620           if (Flags != 0)
1621             Record.push_back(Flags);
1622         }
1623         break;
1624       case Instruction::GetElementPtr: {
1625         Code = bitc::CST_CODE_CE_GEP;
1626         const auto *GO = cast<GEPOperator>(C);
1627         if (GO->isInBounds())
1628           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1629         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1630         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1631           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1632           Record.push_back(VE.getValueID(C->getOperand(i)));
1633         }
1634         break;
1635       }
1636       case Instruction::Select:
1637         Code = bitc::CST_CODE_CE_SELECT;
1638         Record.push_back(VE.getValueID(C->getOperand(0)));
1639         Record.push_back(VE.getValueID(C->getOperand(1)));
1640         Record.push_back(VE.getValueID(C->getOperand(2)));
1641         break;
1642       case Instruction::ExtractElement:
1643         Code = bitc::CST_CODE_CE_EXTRACTELT;
1644         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1645         Record.push_back(VE.getValueID(C->getOperand(0)));
1646         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1647         Record.push_back(VE.getValueID(C->getOperand(1)));
1648         break;
1649       case Instruction::InsertElement:
1650         Code = bitc::CST_CODE_CE_INSERTELT;
1651         Record.push_back(VE.getValueID(C->getOperand(0)));
1652         Record.push_back(VE.getValueID(C->getOperand(1)));
1653         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1654         Record.push_back(VE.getValueID(C->getOperand(2)));
1655         break;
1656       case Instruction::ShuffleVector:
1657         // If the return type and argument types are the same, this is a
1658         // standard shufflevector instruction.  If the types are different,
1659         // then the shuffle is widening or truncating the input vectors, and
1660         // the argument type must also be encoded.
1661         if (C->getType() == C->getOperand(0)->getType()) {
1662           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1663         } else {
1664           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1665           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1666         }
1667         Record.push_back(VE.getValueID(C->getOperand(0)));
1668         Record.push_back(VE.getValueID(C->getOperand(1)));
1669         Record.push_back(VE.getValueID(C->getOperand(2)));
1670         break;
1671       case Instruction::ICmp:
1672       case Instruction::FCmp:
1673         Code = bitc::CST_CODE_CE_CMP;
1674         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1675         Record.push_back(VE.getValueID(C->getOperand(0)));
1676         Record.push_back(VE.getValueID(C->getOperand(1)));
1677         Record.push_back(CE->getPredicate());
1678         break;
1679       }
1680     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1681       Code = bitc::CST_CODE_BLOCKADDRESS;
1682       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1683       Record.push_back(VE.getValueID(BA->getFunction()));
1684       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1685     } else {
1686 #ifndef NDEBUG
1687       C->dump();
1688 #endif
1689       llvm_unreachable("Unknown constant!");
1690     }
1691     Stream.EmitRecord(Code, Record, AbbrevToUse);
1692     Record.clear();
1693   }
1694
1695   Stream.ExitBlock();
1696 }
1697
1698 static void WriteModuleConstants(const ValueEnumerator &VE,
1699                                  BitstreamWriter &Stream) {
1700   const ValueEnumerator::ValueList &Vals = VE.getValues();
1701
1702   // Find the first constant to emit, which is the first non-globalvalue value.
1703   // We know globalvalues have been emitted by WriteModuleInfo.
1704   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1705     if (!isa<GlobalValue>(Vals[i].first)) {
1706       WriteConstants(i, Vals.size(), VE, Stream, true);
1707       return;
1708     }
1709   }
1710 }
1711
1712 /// PushValueAndType - The file has to encode both the value and type id for
1713 /// many values, because we need to know what type to create for forward
1714 /// references.  However, most operands are not forward references, so this type
1715 /// field is not needed.
1716 ///
1717 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1718 /// instruction ID, then it is a forward reference, and it also includes the
1719 /// type ID.  The value ID that is written is encoded relative to the InstID.
1720 static bool PushValueAndType(const Value *V, unsigned InstID,
1721                              SmallVectorImpl<unsigned> &Vals,
1722                              ValueEnumerator &VE) {
1723   unsigned ValID = VE.getValueID(V);
1724   // Make encoding relative to the InstID.
1725   Vals.push_back(InstID - ValID);
1726   if (ValID >= InstID) {
1727     Vals.push_back(VE.getTypeID(V->getType()));
1728     return true;
1729   }
1730   return false;
1731 }
1732
1733 static void WriteOperandBundles(BitstreamWriter &Stream, ImmutableCallSite CS,
1734                                 unsigned InstID, ValueEnumerator &VE) {
1735   SmallVector<unsigned, 64> Record;
1736   LLVMContext &C = CS.getInstruction()->getContext();
1737
1738   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
1739     const auto &Bundle = CS.getOperandBundle(i);
1740     Record.push_back(C.getOperandBundleTagID(Bundle.Tag));
1741
1742     for (auto &Input : Bundle.Inputs)
1743       PushValueAndType(Input, InstID, Record, VE);
1744
1745     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
1746     Record.clear();
1747   }
1748 }
1749
1750 /// pushValue - Like PushValueAndType, but where the type of the value is
1751 /// omitted (perhaps it was already encoded in an earlier operand).
1752 static void pushValue(const Value *V, unsigned InstID,
1753                       SmallVectorImpl<unsigned> &Vals,
1754                       ValueEnumerator &VE) {
1755   unsigned ValID = VE.getValueID(V);
1756   Vals.push_back(InstID - ValID);
1757 }
1758
1759 static void pushValueSigned(const Value *V, unsigned InstID,
1760                             SmallVectorImpl<uint64_t> &Vals,
1761                             ValueEnumerator &VE) {
1762   unsigned ValID = VE.getValueID(V);
1763   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1764   emitSignedInt64(Vals, diff);
1765 }
1766
1767 /// WriteInstruction - Emit an instruction to the specified stream.
1768 static void WriteInstruction(const Instruction &I, unsigned InstID,
1769                              ValueEnumerator &VE, BitstreamWriter &Stream,
1770                              SmallVectorImpl<unsigned> &Vals) {
1771   unsigned Code = 0;
1772   unsigned AbbrevToUse = 0;
1773   VE.setInstructionID(&I);
1774   switch (I.getOpcode()) {
1775   default:
1776     if (Instruction::isCast(I.getOpcode())) {
1777       Code = bitc::FUNC_CODE_INST_CAST;
1778       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1779         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1780       Vals.push_back(VE.getTypeID(I.getType()));
1781       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1782     } else {
1783       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1784       Code = bitc::FUNC_CODE_INST_BINOP;
1785       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1786         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1787       pushValue(I.getOperand(1), InstID, Vals, VE);
1788       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1789       uint64_t Flags = GetOptimizationFlags(&I);
1790       if (Flags != 0) {
1791         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1792           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1793         Vals.push_back(Flags);
1794       }
1795     }
1796     break;
1797
1798   case Instruction::GetElementPtr: {
1799     Code = bitc::FUNC_CODE_INST_GEP;
1800     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1801     auto &GEPInst = cast<GetElementPtrInst>(I);
1802     Vals.push_back(GEPInst.isInBounds());
1803     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1804     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1805       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1806     break;
1807   }
1808   case Instruction::ExtractValue: {
1809     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1810     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1811     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1812     Vals.append(EVI->idx_begin(), EVI->idx_end());
1813     break;
1814   }
1815   case Instruction::InsertValue: {
1816     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1817     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1818     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1819     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1820     Vals.append(IVI->idx_begin(), IVI->idx_end());
1821     break;
1822   }
1823   case Instruction::Select:
1824     Code = bitc::FUNC_CODE_INST_VSELECT;
1825     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1826     pushValue(I.getOperand(2), InstID, Vals, VE);
1827     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1828     break;
1829   case Instruction::ExtractElement:
1830     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1831     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1832     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1833     break;
1834   case Instruction::InsertElement:
1835     Code = bitc::FUNC_CODE_INST_INSERTELT;
1836     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1837     pushValue(I.getOperand(1), InstID, Vals, VE);
1838     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1839     break;
1840   case Instruction::ShuffleVector:
1841     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1842     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1843     pushValue(I.getOperand(1), InstID, Vals, VE);
1844     pushValue(I.getOperand(2), InstID, Vals, VE);
1845     break;
1846   case Instruction::ICmp:
1847   case Instruction::FCmp: {
1848     // compare returning Int1Ty or vector of Int1Ty
1849     Code = bitc::FUNC_CODE_INST_CMP2;
1850     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1851     pushValue(I.getOperand(1), InstID, Vals, VE);
1852     Vals.push_back(cast<CmpInst>(I).getPredicate());
1853     uint64_t Flags = GetOptimizationFlags(&I);
1854     if (Flags != 0)
1855       Vals.push_back(Flags);
1856     break;
1857   }
1858
1859   case Instruction::Ret:
1860     {
1861       Code = bitc::FUNC_CODE_INST_RET;
1862       unsigned NumOperands = I.getNumOperands();
1863       if (NumOperands == 0)
1864         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1865       else if (NumOperands == 1) {
1866         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1867           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1868       } else {
1869         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1870           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1871       }
1872     }
1873     break;
1874   case Instruction::Br:
1875     {
1876       Code = bitc::FUNC_CODE_INST_BR;
1877       const BranchInst &II = cast<BranchInst>(I);
1878       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1879       if (II.isConditional()) {
1880         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1881         pushValue(II.getCondition(), InstID, Vals, VE);
1882       }
1883     }
1884     break;
1885   case Instruction::Switch:
1886     {
1887       Code = bitc::FUNC_CODE_INST_SWITCH;
1888       const SwitchInst &SI = cast<SwitchInst>(I);
1889       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1890       pushValue(SI.getCondition(), InstID, Vals, VE);
1891       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1892       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1893            i != e; ++i) {
1894         Vals.push_back(VE.getValueID(i.getCaseValue()));
1895         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1896       }
1897     }
1898     break;
1899   case Instruction::IndirectBr:
1900     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1901     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1902     // Encode the address operand as relative, but not the basic blocks.
1903     pushValue(I.getOperand(0), InstID, Vals, VE);
1904     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1905       Vals.push_back(VE.getValueID(I.getOperand(i)));
1906     break;
1907
1908   case Instruction::Invoke: {
1909     const InvokeInst *II = cast<InvokeInst>(&I);
1910     const Value *Callee = II->getCalledValue();
1911     FunctionType *FTy = II->getFunctionType();
1912
1913     if (II->hasOperandBundles())
1914       WriteOperandBundles(Stream, II, InstID, VE);
1915
1916     Code = bitc::FUNC_CODE_INST_INVOKE;
1917
1918     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1919     Vals.push_back(II->getCallingConv() | 1 << 13);
1920     Vals.push_back(VE.getValueID(II->getNormalDest()));
1921     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1922     Vals.push_back(VE.getTypeID(FTy));
1923     PushValueAndType(Callee, InstID, Vals, VE);
1924
1925     // Emit value #'s for the fixed parameters.
1926     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1927       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1928
1929     // Emit type/value pairs for varargs params.
1930     if (FTy->isVarArg()) {
1931       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1932            i != e; ++i)
1933         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1934     }
1935     break;
1936   }
1937   case Instruction::Resume:
1938     Code = bitc::FUNC_CODE_INST_RESUME;
1939     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1940     break;
1941   case Instruction::CleanupRet: {
1942     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
1943     const auto &CRI = cast<CleanupReturnInst>(I);
1944     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
1945     if (CRI.hasUnwindDest())
1946       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
1947     break;
1948   }
1949   case Instruction::CatchRet: {
1950     Code = bitc::FUNC_CODE_INST_CATCHRET;
1951     const auto &CRI = cast<CatchReturnInst>(I);
1952     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
1953     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
1954     break;
1955   }
1956   case Instruction::CatchPad: {
1957     Code = bitc::FUNC_CODE_INST_CATCHPAD;
1958     const auto &CPI = cast<CatchPadInst>(I);
1959     Vals.push_back(VE.getValueID(CPI.getNormalDest()));
1960     Vals.push_back(VE.getValueID(CPI.getUnwindDest()));
1961     unsigned NumArgOperands = CPI.getNumArgOperands();
1962     Vals.push_back(NumArgOperands);
1963     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1964       PushValueAndType(CPI.getArgOperand(Op), InstID, Vals, VE);
1965     break;
1966   }
1967   case Instruction::TerminatePad: {
1968     Code = bitc::FUNC_CODE_INST_TERMINATEPAD;
1969     const auto &TPI = cast<TerminatePadInst>(I);
1970     Vals.push_back(TPI.hasUnwindDest());
1971     if (TPI.hasUnwindDest())
1972       Vals.push_back(VE.getValueID(TPI.getUnwindDest()));
1973     unsigned NumArgOperands = TPI.getNumArgOperands();
1974     Vals.push_back(NumArgOperands);
1975     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1976       PushValueAndType(TPI.getArgOperand(Op), InstID, Vals, VE);
1977     break;
1978   }
1979   case Instruction::CleanupPad: {
1980     Code = bitc::FUNC_CODE_INST_CLEANUPPAD;
1981     const auto &CPI = cast<CleanupPadInst>(I);
1982     unsigned NumOperands = CPI.getNumOperands();
1983     Vals.push_back(NumOperands);
1984     for (unsigned Op = 0; Op != NumOperands; ++Op)
1985       PushValueAndType(CPI.getOperand(Op), InstID, Vals, VE);
1986     break;
1987   }
1988   case Instruction::CatchEndPad: {
1989     Code = bitc::FUNC_CODE_INST_CATCHENDPAD;
1990     const auto &CEPI = cast<CatchEndPadInst>(I);
1991     if (CEPI.hasUnwindDest())
1992       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
1993     break;
1994   }
1995   case Instruction::CleanupEndPad: {
1996     Code = bitc::FUNC_CODE_INST_CLEANUPENDPAD;
1997     const auto &CEPI = cast<CleanupEndPadInst>(I);
1998     pushValue(CEPI.getCleanupPad(), InstID, Vals, VE);
1999     if (CEPI.hasUnwindDest())
2000       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
2001     break;
2002   }
2003   case Instruction::Unreachable:
2004     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2005     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2006     break;
2007
2008   case Instruction::PHI: {
2009     const PHINode &PN = cast<PHINode>(I);
2010     Code = bitc::FUNC_CODE_INST_PHI;
2011     // With the newer instruction encoding, forward references could give
2012     // negative valued IDs.  This is most common for PHIs, so we use
2013     // signed VBRs.
2014     SmallVector<uint64_t, 128> Vals64;
2015     Vals64.push_back(VE.getTypeID(PN.getType()));
2016     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2017       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
2018       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2019     }
2020     // Emit a Vals64 vector and exit.
2021     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2022     Vals64.clear();
2023     return;
2024   }
2025
2026   case Instruction::LandingPad: {
2027     const LandingPadInst &LP = cast<LandingPadInst>(I);
2028     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2029     Vals.push_back(VE.getTypeID(LP.getType()));
2030     Vals.push_back(LP.isCleanup());
2031     Vals.push_back(LP.getNumClauses());
2032     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2033       if (LP.isCatch(I))
2034         Vals.push_back(LandingPadInst::Catch);
2035       else
2036         Vals.push_back(LandingPadInst::Filter);
2037       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
2038     }
2039     break;
2040   }
2041
2042   case Instruction::Alloca: {
2043     Code = bitc::FUNC_CODE_INST_ALLOCA;
2044     const AllocaInst &AI = cast<AllocaInst>(I);
2045     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2046     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2047     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2048     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2049     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2050            "not enough bits for maximum alignment");
2051     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2052     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2053     AlignRecord |= 1 << 6;
2054     // Reserve bit 7 for SwiftError flag.
2055     // AlignRecord |= AI.isSwiftError() << 7;
2056     Vals.push_back(AlignRecord);
2057     break;
2058   }
2059
2060   case Instruction::Load:
2061     if (cast<LoadInst>(I).isAtomic()) {
2062       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2063       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2064     } else {
2065       Code = bitc::FUNC_CODE_INST_LOAD;
2066       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2067         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2068     }
2069     Vals.push_back(VE.getTypeID(I.getType()));
2070     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2071     Vals.push_back(cast<LoadInst>(I).isVolatile());
2072     if (cast<LoadInst>(I).isAtomic()) {
2073       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2074       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2075     }
2076     break;
2077   case Instruction::Store:
2078     if (cast<StoreInst>(I).isAtomic())
2079       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2080     else
2081       Code = bitc::FUNC_CODE_INST_STORE;
2082     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2083     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2084     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2085     Vals.push_back(cast<StoreInst>(I).isVolatile());
2086     if (cast<StoreInst>(I).isAtomic()) {
2087       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2088       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2089     }
2090     break;
2091   case Instruction::AtomicCmpXchg:
2092     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2093     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2094     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
2095     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2096     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2097     Vals.push_back(GetEncodedOrdering(
2098                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2099     Vals.push_back(GetEncodedSynchScope(
2100                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2101     Vals.push_back(GetEncodedOrdering(
2102                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2103     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2104     break;
2105   case Instruction::AtomicRMW:
2106     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2107     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2108     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2109     Vals.push_back(GetEncodedRMWOperation(
2110                      cast<AtomicRMWInst>(I).getOperation()));
2111     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2112     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2113     Vals.push_back(GetEncodedSynchScope(
2114                      cast<AtomicRMWInst>(I).getSynchScope()));
2115     break;
2116   case Instruction::Fence:
2117     Code = bitc::FUNC_CODE_INST_FENCE;
2118     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2119     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2120     break;
2121   case Instruction::Call: {
2122     const CallInst &CI = cast<CallInst>(I);
2123     FunctionType *FTy = CI.getFunctionType();
2124
2125     if (CI.hasOperandBundles())
2126       WriteOperandBundles(Stream, &CI, InstID, VE);
2127
2128     Code = bitc::FUNC_CODE_INST_CALL;
2129
2130     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2131     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
2132                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
2133     Vals.push_back(VE.getTypeID(FTy));
2134     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2135
2136     // Emit value #'s for the fixed parameters.
2137     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2138       // Check for labels (can happen with asm labels).
2139       if (FTy->getParamType(i)->isLabelTy())
2140         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2141       else
2142         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2143     }
2144
2145     // Emit type/value pairs for varargs params.
2146     if (FTy->isVarArg()) {
2147       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2148            i != e; ++i)
2149         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2150     }
2151     break;
2152   }
2153   case Instruction::VAArg:
2154     Code = bitc::FUNC_CODE_INST_VAARG;
2155     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2156     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2157     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2158     break;
2159   }
2160
2161   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2162   Vals.clear();
2163 }
2164
2165 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
2166
2167 /// Determine the encoding to use for the given string name and length.
2168 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
2169   bool isChar6 = true;
2170   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
2171     if (isChar6)
2172       isChar6 = BitCodeAbbrevOp::isChar6(*C);
2173     if ((unsigned char)*C & 128)
2174       // don't bother scanning the rest.
2175       return SE_Fixed8;
2176   }
2177   if (isChar6)
2178     return SE_Char6;
2179   else
2180     return SE_Fixed7;
2181 }
2182
2183 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2184 /// BitcodeStartBit and FunctionIndex are only passed for the module-level
2185 /// VST, where we are including a function bitcode index and need to
2186 /// backpatch the VST forward declaration record.
2187 static void WriteValueSymbolTable(
2188     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2189     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2190     uint64_t BitcodeStartBit = 0,
2191     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> *FunctionIndex =
2192         nullptr) {
2193   if (VST.empty()) {
2194     // WriteValueSymbolTableForwardDecl should have returned early as
2195     // well. Ensure this handling remains in sync by asserting that
2196     // the placeholder offset is not set.
2197     assert(VSTOffsetPlaceholder == 0);
2198     return;
2199   }
2200
2201   if (VSTOffsetPlaceholder > 0) {
2202     // Get the offset of the VST we are writing, and backpatch it into
2203     // the VST forward declaration record.
2204     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2205     // The BitcodeStartBit was the stream offset of the actual bitcode
2206     // (e.g. excluding any initial darwin header).
2207     VSTOffset -= BitcodeStartBit;
2208     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2209     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2210   }
2211
2212   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2213
2214   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2215   // records, which are not used in the per-function VSTs.
2216   unsigned FnEntry8BitAbbrev;
2217   unsigned FnEntry7BitAbbrev;
2218   unsigned FnEntry6BitAbbrev;
2219   if (VSTOffsetPlaceholder > 0) {
2220     // 8-bit fixed-width VST_FNENTRY function strings.
2221     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2222     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2227     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2228
2229     // 7-bit fixed width VST_FNENTRY function strings.
2230     Abbv = new BitCodeAbbrev();
2231     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2236     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2237
2238     // 6-bit char6 VST_FNENTRY function strings.
2239     Abbv = new BitCodeAbbrev();
2240     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2241     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2245     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2246   }
2247
2248   // FIXME: Set up the abbrev, we know how many values there are!
2249   // FIXME: We know if the type names can use 7-bit ascii.
2250   SmallVector<unsigned, 64> NameVals;
2251
2252   for (const ValueName &Name : VST) {
2253     // Figure out the encoding to use for the name.
2254     StringEncoding Bits =
2255         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2256
2257     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2258     NameVals.push_back(VE.getValueID(Name.getValue()));
2259
2260     Function *F = dyn_cast<Function>(Name.getValue());
2261     if (!F) {
2262       // If value is an alias, need to get the aliased base object to
2263       // see if it is a function.
2264       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2265       if (GA && GA->getBaseObject())
2266         F = dyn_cast<Function>(GA->getBaseObject());
2267     }
2268
2269     // VST_ENTRY:   [valueid, namechar x N]
2270     // VST_FNENTRY: [valueid, funcoffset, namechar x N]
2271     // VST_BBENTRY: [bbid, namechar x N]
2272     unsigned Code;
2273     if (isa<BasicBlock>(Name.getValue())) {
2274       Code = bitc::VST_CODE_BBENTRY;
2275       if (Bits == SE_Char6)
2276         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2277     } else if (F && !F->isDeclaration()) {
2278       // Must be the module-level VST, where we pass in the Index and
2279       // have a VSTOffsetPlaceholder. The function-level VST should not
2280       // contain any Function symbols.
2281       assert(FunctionIndex);
2282       assert(VSTOffsetPlaceholder > 0);
2283
2284       // Save the word offset of the function (from the start of the
2285       // actual bitcode written to the stream).
2286       assert(FunctionIndex->count(F) == 1);
2287       uint64_t BitcodeIndex =
2288           (*FunctionIndex)[F]->bitcodeIndex() - BitcodeStartBit;
2289       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2290       NameVals.push_back(BitcodeIndex / 32);
2291
2292       Code = bitc::VST_CODE_FNENTRY;
2293       AbbrevToUse = FnEntry8BitAbbrev;
2294       if (Bits == SE_Char6)
2295         AbbrevToUse = FnEntry6BitAbbrev;
2296       else if (Bits == SE_Fixed7)
2297         AbbrevToUse = FnEntry7BitAbbrev;
2298     } else {
2299       Code = bitc::VST_CODE_ENTRY;
2300       if (Bits == SE_Char6)
2301         AbbrevToUse = VST_ENTRY_6_ABBREV;
2302       else if (Bits == SE_Fixed7)
2303         AbbrevToUse = VST_ENTRY_7_ABBREV;
2304     }
2305
2306     for (const auto P : Name.getKey())
2307       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)
2366         NameVals.push_back((unsigned char)P);
2367
2368       // Emit the finished record.
2369       Stream.EmitRecord(bitc::VST_CODE_COMBINED_FNENTRY, NameVals, AbbrevToUse);
2370       NameVals.clear();
2371     }
2372   }
2373   Stream.ExitBlock();
2374 }
2375
2376 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2377                          BitstreamWriter &Stream) {
2378   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2379   unsigned Code;
2380   if (isa<BasicBlock>(Order.V))
2381     Code = bitc::USELIST_CODE_BB;
2382   else
2383     Code = bitc::USELIST_CODE_DEFAULT;
2384
2385   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2386   Record.push_back(VE.getValueID(Order.V));
2387   Stream.EmitRecord(Code, Record);
2388 }
2389
2390 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2391                               BitstreamWriter &Stream) {
2392   assert(VE.shouldPreserveUseListOrder() &&
2393          "Expected to be preserving use-list order");
2394
2395   auto hasMore = [&]() {
2396     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2397   };
2398   if (!hasMore())
2399     // Nothing to do.
2400     return;
2401
2402   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2403   while (hasMore()) {
2404     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2405     VE.UseListOrders.pop_back();
2406   }
2407   Stream.ExitBlock();
2408 }
2409
2410 /// \brief Save information for the given function into the function index.
2411 ///
2412 /// At a minimum this saves the bitcode index of the function record that
2413 /// was just written. However, if we are emitting function summary information,
2414 /// for example for ThinLTO, then a \a FunctionSummary object is created
2415 /// to hold the provided summary information.
2416 static void SaveFunctionInfo(
2417     const Function &F,
2418     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2419     unsigned NumInsts, uint64_t BitcodeIndex, bool EmitFunctionSummary) {
2420   std::unique_ptr<FunctionSummary> FuncSummary;
2421   if (EmitFunctionSummary) {
2422     FuncSummary = llvm::make_unique<FunctionSummary>(NumInsts);
2423     FuncSummary->setLocalFunction(F.hasLocalLinkage());
2424   }
2425   FunctionIndex[&F] =
2426       llvm::make_unique<FunctionInfo>(BitcodeIndex, std::move(FuncSummary));
2427 }
2428
2429 /// Emit a function body to the module stream.
2430 static void WriteFunction(
2431     const Function &F, ValueEnumerator &VE, BitstreamWriter &Stream,
2432     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2433     bool EmitFunctionSummary) {
2434   // Save the bitcode index of the start of this function block for recording
2435   // in the VST.
2436   uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
2437
2438   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2439   VE.incorporateFunction(F);
2440
2441   SmallVector<unsigned, 64> Vals;
2442
2443   // Emit the number of basic blocks, so the reader can create them ahead of
2444   // time.
2445   Vals.push_back(VE.getBasicBlocks().size());
2446   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2447   Vals.clear();
2448
2449   // If there are function-local constants, emit them now.
2450   unsigned CstStart, CstEnd;
2451   VE.getFunctionConstantRange(CstStart, CstEnd);
2452   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2453
2454   // If there is function-local metadata, emit it now.
2455   WriteFunctionLocalMetadata(F, VE, Stream);
2456
2457   // Keep a running idea of what the instruction ID is.
2458   unsigned InstID = CstEnd;
2459
2460   bool NeedsMetadataAttachment = F.hasMetadata();
2461
2462   DILocation *LastDL = nullptr;
2463   unsigned NumInsts = 0;
2464
2465   // Finally, emit all the instructions, in order.
2466   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2467     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2468          I != E; ++I) {
2469       WriteInstruction(*I, InstID, VE, Stream, Vals);
2470
2471       if (!isa<DbgInfoIntrinsic>(I))
2472         ++NumInsts;
2473
2474       if (!I->getType()->isVoidTy())
2475         ++InstID;
2476
2477       // If the instruction has metadata, write a metadata attachment later.
2478       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2479
2480       // If the instruction has a debug location, emit it.
2481       DILocation *DL = I->getDebugLoc();
2482       if (!DL)
2483         continue;
2484
2485       if (DL == LastDL) {
2486         // Just repeat the same debug loc as last time.
2487         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2488         continue;
2489       }
2490
2491       Vals.push_back(DL->getLine());
2492       Vals.push_back(DL->getColumn());
2493       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2494       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2495       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2496       Vals.clear();
2497
2498       LastDL = DL;
2499     }
2500
2501   // Emit names for all the instructions etc.
2502   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2503
2504   if (NeedsMetadataAttachment)
2505     WriteMetadataAttachment(F, VE, Stream);
2506   if (VE.shouldPreserveUseListOrder())
2507     WriteUseListBlock(&F, VE, Stream);
2508   VE.purgeFunction();
2509   Stream.ExitBlock();
2510
2511   SaveFunctionInfo(F, FunctionIndex, NumInsts, BitcodeIndex,
2512                    EmitFunctionSummary);
2513 }
2514
2515 // Emit blockinfo, which defines the standard abbreviations etc.
2516 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2517   // We only want to emit block info records for blocks that have multiple
2518   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2519   // Other blocks can define their abbrevs inline.
2520   Stream.EnterBlockInfoBlock(2);
2521
2522   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2523     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2528     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2529                                    Abbv) != VST_ENTRY_8_ABBREV)
2530       llvm_unreachable("Unexpected abbrev ordering!");
2531   }
2532
2533   { // 7-bit fixed width VST_ENTRY strings.
2534     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2535     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2539     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2540                                    Abbv) != VST_ENTRY_7_ABBREV)
2541       llvm_unreachable("Unexpected abbrev ordering!");
2542   }
2543   { // 6-bit char6 VST_ENTRY strings.
2544     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2545     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2549     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2550                                    Abbv) != VST_ENTRY_6_ABBREV)
2551       llvm_unreachable("Unexpected abbrev ordering!");
2552   }
2553   { // 6-bit char6 VST_BBENTRY strings.
2554     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2555     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2556     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2557     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2559     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2560                                    Abbv) != VST_BBENTRY_6_ABBREV)
2561       llvm_unreachable("Unexpected abbrev ordering!");
2562   }
2563
2564
2565
2566   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2567     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2568     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2570                               VE.computeBitsRequiredForTypeIndicies()));
2571     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2572                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2573       llvm_unreachable("Unexpected abbrev ordering!");
2574   }
2575
2576   { // INTEGER abbrev for CONSTANTS_BLOCK.
2577     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2578     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2580     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2581                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2582       llvm_unreachable("Unexpected abbrev ordering!");
2583   }
2584
2585   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2586     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2587     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2590                               VE.computeBitsRequiredForTypeIndicies()));
2591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2592
2593     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2594                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2595       llvm_unreachable("Unexpected abbrev ordering!");
2596   }
2597   { // NULL abbrev for CONSTANTS_BLOCK.
2598     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2599     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2600     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2601                                    Abbv) != CONSTANTS_NULL_Abbrev)
2602       llvm_unreachable("Unexpected abbrev ordering!");
2603   }
2604
2605   // FIXME: This should only use space for first class types!
2606
2607   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2608     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2609     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2610     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2612                               VE.computeBitsRequiredForTypeIndicies()));
2613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2614     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2615     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2616                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2617       llvm_unreachable("Unexpected abbrev ordering!");
2618   }
2619   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2620     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2621     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2623     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2624     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2625     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2626                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2627       llvm_unreachable("Unexpected abbrev ordering!");
2628   }
2629   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2630     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2631     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2636     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2637                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2638       llvm_unreachable("Unexpected abbrev ordering!");
2639   }
2640   { // INST_CAST abbrev for FUNCTION_BLOCK.
2641     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2642     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2645                               VE.computeBitsRequiredForTypeIndicies()));
2646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2647     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2648                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2649       llvm_unreachable("Unexpected abbrev ordering!");
2650   }
2651
2652   { // INST_RET abbrev for FUNCTION_BLOCK.
2653     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2654     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2655     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2656                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2657       llvm_unreachable("Unexpected abbrev ordering!");
2658   }
2659   { // INST_RET abbrev for FUNCTION_BLOCK.
2660     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2661     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2663     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2664                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2665       llvm_unreachable("Unexpected abbrev ordering!");
2666   }
2667   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2668     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2669     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2670     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2671                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2672       llvm_unreachable("Unexpected abbrev ordering!");
2673   }
2674   {
2675     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2676     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2679                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2682     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2683         FUNCTION_INST_GEP_ABBREV)
2684       llvm_unreachable("Unexpected abbrev ordering!");
2685   }
2686
2687   Stream.ExitBlock();
2688 }
2689
2690 /// Write the module path strings, currently only used when generating
2691 /// a combined index file.
2692 static void WriteModStrings(const FunctionInfoIndex &I,
2693                             BitstreamWriter &Stream) {
2694   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
2695
2696   // TODO: See which abbrev sizes we actually need to emit
2697
2698   // 8-bit fixed-width MST_ENTRY strings.
2699   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2700   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2701   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2702   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2703   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2704   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
2705
2706   // 7-bit fixed width MST_ENTRY strings.
2707   Abbv = new BitCodeAbbrev();
2708   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2709   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2710   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2711   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2712   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
2713
2714   // 6-bit char6 MST_ENTRY strings.
2715   Abbv = new BitCodeAbbrev();
2716   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
2717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2719   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2720   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
2721
2722   SmallVector<unsigned, 64> NameVals;
2723   for (const StringMapEntry<uint64_t> &MPSE : I.modPathStringEntries()) {
2724     StringEncoding Bits =
2725         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
2726     unsigned AbbrevToUse = Abbrev8Bit;
2727     if (Bits == SE_Char6)
2728       AbbrevToUse = Abbrev6Bit;
2729     else if (Bits == SE_Fixed7)
2730       AbbrevToUse = Abbrev7Bit;
2731
2732     NameVals.push_back(MPSE.getValue());
2733
2734     for (const auto P : MPSE.getKey())
2735       NameVals.push_back((unsigned char)P);
2736
2737     // Emit the finished record.
2738     Stream.EmitRecord(bitc::MST_CODE_ENTRY, NameVals, AbbrevToUse);
2739     NameVals.clear();
2740   }
2741   Stream.ExitBlock();
2742 }
2743
2744 // Helper to emit a single function summary record.
2745 static void WritePerModuleFunctionSummaryRecord(
2746     SmallVector<unsigned, 64> &NameVals, FunctionSummary *FS, unsigned ValueID,
2747     unsigned FSAbbrev, BitstreamWriter &Stream) {
2748   assert(FS);
2749   NameVals.push_back(ValueID);
2750   NameVals.push_back(FS->isLocalFunction());
2751   NameVals.push_back(FS->instCount());
2752
2753   // Emit the finished record.
2754   Stream.EmitRecord(bitc::FS_CODE_PERMODULE_ENTRY, NameVals, FSAbbrev);
2755   NameVals.clear();
2756 }
2757
2758 /// Emit the per-module function summary section alongside the rest of
2759 /// the module's bitcode.
2760 static void WritePerModuleFunctionSummary(
2761     DenseMap<const Function *, std::unique_ptr<FunctionInfo>> &FunctionIndex,
2762     const Module *M, const ValueEnumerator &VE, BitstreamWriter &Stream) {
2763   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2764
2765   // Abbrev for FS_CODE_PERMODULE_ENTRY.
2766   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2767   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_PERMODULE_ENTRY));
2768   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
2769   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // islocal
2770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
2771   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2772
2773   SmallVector<unsigned, 64> NameVals;
2774   for (auto &I : FunctionIndex) {
2775     // Skip anonymous functions. We will emit a function summary for
2776     // any aliases below.
2777     if (!I.first->hasName())
2778       continue;
2779
2780     WritePerModuleFunctionSummaryRecord(
2781         NameVals, I.second->functionSummary(),
2782         VE.getValueID(M->getValueSymbolTable().lookup(I.first->getName())),
2783         FSAbbrev, Stream);
2784   }
2785
2786   for (const GlobalAlias &A : M->aliases()) {
2787     if (!A.getBaseObject())
2788       continue;
2789     const Function *F = dyn_cast<Function>(A.getBaseObject());
2790     if (!F || F->isDeclaration())
2791       continue;
2792
2793     assert(FunctionIndex.count(F) == 1);
2794     WritePerModuleFunctionSummaryRecord(
2795         NameVals, FunctionIndex[F]->functionSummary(),
2796         VE.getValueID(M->getValueSymbolTable().lookup(A.getName())), FSAbbrev,
2797         Stream);
2798   }
2799
2800   Stream.ExitBlock();
2801 }
2802
2803 /// Emit the combined function summary section into the combined index
2804 /// file.
2805 static void WriteCombinedFunctionSummary(const FunctionInfoIndex &I,
2806                                          BitstreamWriter &Stream) {
2807   Stream.EnterSubblock(bitc::FUNCTION_SUMMARY_BLOCK_ID, 3);
2808
2809   // Abbrev for FS_CODE_COMBINED_ENTRY.
2810   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2811   Abbv->Add(BitCodeAbbrevOp(bitc::FS_CODE_COMBINED_ENTRY));
2812   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // modid
2813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // instcount
2814   unsigned FSAbbrev = Stream.EmitAbbrev(Abbv);
2815
2816   SmallVector<unsigned, 64> NameVals;
2817   for (const auto &FII : I) {
2818     for (auto &FI : FII.getValue()) {
2819       FunctionSummary *FS = FI->functionSummary();
2820       assert(FS);
2821
2822       NameVals.push_back(I.getModuleId(FS->modulePath()));
2823       NameVals.push_back(FS->instCount());
2824
2825       // Record the starting offset of this summary entry for use
2826       // in the VST entry. Add the current code size since the
2827       // reader will invoke readRecord after the abbrev id read.
2828       FI->setBitcodeIndex(Stream.GetCurrentBitNo() + Stream.GetAbbrevIDWidth());
2829
2830       // Emit the finished record.
2831       Stream.EmitRecord(bitc::FS_CODE_COMBINED_ENTRY, NameVals, FSAbbrev);
2832       NameVals.clear();
2833     }
2834   }
2835
2836   Stream.ExitBlock();
2837 }
2838
2839 // Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
2840 // current llvm version, and a record for the epoch number.
2841 static void WriteIdentificationBlock(const Module *M, BitstreamWriter &Stream) {
2842   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
2843
2844   // Write the "user readable" string identifying the bitcode producer
2845   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2846   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
2847   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2848   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2849   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
2850   WriteStringRecord(bitc::IDENTIFICATION_CODE_STRING,
2851                     "LLVM" LLVM_VERSION_STRING, StringAbbrev, Stream);
2852
2853   // Write the epoch version
2854   Abbv = new BitCodeAbbrev();
2855   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
2856   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2857   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
2858   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
2859   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
2860   Stream.ExitBlock();
2861 }
2862
2863 /// WriteModule - Emit the specified module to the bitstream.
2864 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2865                         bool ShouldPreserveUseListOrder,
2866                         uint64_t BitcodeStartBit, bool EmitFunctionSummary) {
2867   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2868
2869   SmallVector<unsigned, 1> Vals;
2870   unsigned CurVersion = 1;
2871   Vals.push_back(CurVersion);
2872   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2873
2874   // Analyze the module, enumerating globals, functions, etc.
2875   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2876
2877   // Emit blockinfo, which defines the standard abbreviations etc.
2878   WriteBlockInfo(VE, Stream);
2879
2880   // Emit information about attribute groups.
2881   WriteAttributeGroupTable(VE, Stream);
2882
2883   // Emit information about parameter attributes.
2884   WriteAttributeTable(VE, Stream);
2885
2886   // Emit information describing all of the types in the module.
2887   WriteTypeTable(VE, Stream);
2888
2889   writeComdats(VE, Stream);
2890
2891   // Emit top-level description of module, including target triple, inline asm,
2892   // descriptors for global variables, and function prototype info.
2893   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
2894
2895   // Emit constants.
2896   WriteModuleConstants(VE, Stream);
2897
2898   // Emit metadata.
2899   WriteModuleMetadata(M, VE, Stream);
2900
2901   // Emit metadata.
2902   WriteModuleMetadataStore(M, Stream);
2903
2904   // Emit module-level use-lists.
2905   if (VE.shouldPreserveUseListOrder())
2906     WriteUseListBlock(nullptr, VE, Stream);
2907
2908   WriteOperandBundleTags(M, Stream);
2909
2910   // Emit function bodies.
2911   DenseMap<const Function *, std::unique_ptr<FunctionInfo>> FunctionIndex;
2912   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2913     if (!F->isDeclaration())
2914       WriteFunction(*F, VE, Stream, FunctionIndex, EmitFunctionSummary);
2915
2916   // Need to write after the above call to WriteFunction which populates
2917   // the summary information in the index.
2918   if (EmitFunctionSummary)
2919     WritePerModuleFunctionSummary(FunctionIndex, M, VE, Stream);
2920
2921   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
2922                         VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
2923
2924   Stream.ExitBlock();
2925 }
2926
2927 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2928 /// header and trailer to make it compatible with the system archiver.  To do
2929 /// this we emit the following header, and then emit a trailer that pads the
2930 /// file out to be a multiple of 16 bytes.
2931 ///
2932 /// struct bc_header {
2933 ///   uint32_t Magic;         // 0x0B17C0DE
2934 ///   uint32_t Version;       // Version, currently always 0.
2935 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2936 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2937 ///   uint32_t CPUType;       // CPU specifier.
2938 ///   ... potentially more later ...
2939 /// };
2940 enum {
2941   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2942   DarwinBCHeaderSize = 5*4
2943 };
2944
2945 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2946                                uint32_t &Position) {
2947   support::endian::write32le(&Buffer[Position], Value);
2948   Position += 4;
2949 }
2950
2951 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2952                                          const Triple &TT) {
2953   unsigned CPUType = ~0U;
2954
2955   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2956   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2957   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2958   // specific constants here because they are implicitly part of the Darwin ABI.
2959   enum {
2960     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2961     DARWIN_CPU_TYPE_X86        = 7,
2962     DARWIN_CPU_TYPE_ARM        = 12,
2963     DARWIN_CPU_TYPE_POWERPC    = 18
2964   };
2965
2966   Triple::ArchType Arch = TT.getArch();
2967   if (Arch == Triple::x86_64)
2968     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2969   else if (Arch == Triple::x86)
2970     CPUType = DARWIN_CPU_TYPE_X86;
2971   else if (Arch == Triple::ppc)
2972     CPUType = DARWIN_CPU_TYPE_POWERPC;
2973   else if (Arch == Triple::ppc64)
2974     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2975   else if (Arch == Triple::arm || Arch == Triple::thumb)
2976     CPUType = DARWIN_CPU_TYPE_ARM;
2977
2978   // Traditional Bitcode starts after header.
2979   assert(Buffer.size() >= DarwinBCHeaderSize &&
2980          "Expected header size to be reserved");
2981   unsigned BCOffset = DarwinBCHeaderSize;
2982   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2983
2984   // Write the magic and version.
2985   unsigned Position = 0;
2986   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2987   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2988   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2989   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2990   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2991
2992   // If the file is not a multiple of 16 bytes, insert dummy padding.
2993   while (Buffer.size() & 15)
2994     Buffer.push_back(0);
2995 }
2996
2997 /// Helper to write the header common to all bitcode files.
2998 static void WriteBitcodeHeader(BitstreamWriter &Stream) {
2999   // Emit the file header.
3000   Stream.Emit((unsigned)'B', 8);
3001   Stream.Emit((unsigned)'C', 8);
3002   Stream.Emit(0x0, 4);
3003   Stream.Emit(0xC, 4);
3004   Stream.Emit(0xE, 4);
3005   Stream.Emit(0xD, 4);
3006 }
3007
3008 /// WriteBitcodeToFile - Write the specified module to the specified output
3009 /// stream.
3010 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3011                               bool ShouldPreserveUseListOrder,
3012                               bool EmitFunctionSummary) {
3013   SmallVector<char, 0> Buffer;
3014   Buffer.reserve(256*1024);
3015
3016   // If this is darwin or another generic macho target, reserve space for the
3017   // header.
3018   Triple TT(M->getTargetTriple());
3019   if (TT.isOSDarwin())
3020     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
3021
3022   // Emit the module into the buffer.
3023   {
3024     BitstreamWriter Stream(Buffer);
3025     // Save the start bit of the actual bitcode, in case there is space
3026     // saved at the start for the darwin header above. The reader stream
3027     // will start at the bitcode, and we need the offset of the VST
3028     // to line up.
3029     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
3030
3031     // Emit the file header.
3032     WriteBitcodeHeader(Stream);
3033
3034     WriteIdentificationBlock(M, Stream);
3035
3036     // Emit the module.
3037     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit,
3038                 EmitFunctionSummary);
3039   }
3040
3041   if (TT.isOSDarwin())
3042     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
3043
3044   // Write the generated bitstream to "Out".
3045   Out.write((char*)&Buffer.front(), Buffer.size());
3046 }
3047
3048 // Write the specified function summary index to the given raw output stream,
3049 // where it will be written in a new bitcode block. This is used when
3050 // writing the combined index file for ThinLTO.
3051 void llvm::WriteFunctionSummaryToFile(const FunctionInfoIndex &Index,
3052                                       raw_ostream &Out) {
3053   SmallVector<char, 0> Buffer;
3054   Buffer.reserve(256 * 1024);
3055
3056   BitstreamWriter Stream(Buffer);
3057
3058   // Emit the bitcode header.
3059   WriteBitcodeHeader(Stream);
3060
3061   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3062
3063   SmallVector<unsigned, 1> Vals;
3064   unsigned CurVersion = 1;
3065   Vals.push_back(CurVersion);
3066   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3067
3068   // Write the module paths in the combined index.
3069   WriteModStrings(Index, Stream);
3070
3071   // Write the function summary combined index records.
3072   WriteCombinedFunctionSummary(Index, Stream);
3073
3074   // Need a special VST writer for the combined index (we don't have a
3075   // real VST and real values when this is invoked).
3076   WriteCombinedValueSymbolTable(Index, Stream);
3077
3078   Stream.ExitBlock();
3079
3080   Out.write((char *)&Buffer.front(), Buffer.size());
3081 }