lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "ValueEnumerator.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Bitcode/BitstreamWriter.h"
  18 #include "llvm/Bitcode/LLVMBitCodes.h"
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DebugInfoMetadata.h"
  21 #include "llvm/IR/DerivedTypes.h"
  22 #include "llvm/IR/InlineAsm.h"
  23 #include "llvm/IR/Instructions.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/IR/Operator.h"
  26 #include "llvm/IR/UseListOrder.h"
  27 #include "llvm/IR/ValueSymbolTable.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/MathExtras.h"
  31 #include "llvm/Support/Program.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 #include <cctype>
  34 #include <map>
  35 using namespace llvm;
  36
  37 /// These are manifest constants used by the bitcode writer. They do not need to
  38 /// be kept in sync with the reader, but need to be consistent within this file.
  39 enum {
  40   // VALUE_SYMTAB_BLOCK abbrev id's.
  41   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  42   VST_ENTRY_7_ABBREV,
  43   VST_ENTRY_6_ABBREV,
  44   VST_BBENTRY_6_ABBREV,
  45
  46   // CONSTANTS_BLOCK abbrev id's.
  47   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   CONSTANTS_INTEGER_ABBREV,
  49   CONSTANTS_CE_CAST_Abbrev,
  50   CONSTANTS_NULL_Abbrev,
  51
  52   // FUNCTION_BLOCK abbrev id's.
  53   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   FUNCTION_INST_BINOP_ABBREV,
  55   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  56   FUNCTION_INST_CAST_ABBREV,
  57   FUNCTION_INST_RET_VOID_ABBREV,
  58   FUNCTION_INST_RET_VAL_ABBREV,
  59   FUNCTION_INST_UNREACHABLE_ABBREV,
  60   FUNCTION_INST_GEP_ABBREV,
  61 };
  62
  63 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  64   switch (Opcode) {
  65   default: llvm_unreachable("Unknown cast instruction!");
  66   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  67   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  68   case Instruction::SExt    : return bitc::CAST_SEXT;
  69   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  70   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  71   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  72   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  73   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  74   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  75   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  76   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  77   case Instruction::BitCast : return bitc::CAST_BITCAST;
  78   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  79   }
  80 }
  81
  82 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  83   switch (Opcode) {
  84   default: llvm_unreachable("Unknown binary instruction!");
  85   case Instruction::Add:
  86   case Instruction::FAdd: return bitc::BINOP_ADD;
  87   case Instruction::Sub:
  88   case Instruction::FSub: return bitc::BINOP_SUB;
  89   case Instruction::Mul:
  90   case Instruction::FMul: return bitc::BINOP_MUL;
  91   case Instruction::UDiv: return bitc::BINOP_UDIV;
  92   case Instruction::FDiv:
  93   case Instruction::SDiv: return bitc::BINOP_SDIV;
  94   case Instruction::URem: return bitc::BINOP_UREM;
  95   case Instruction::FRem:
  96   case Instruction::SRem: return bitc::BINOP_SREM;
  97   case Instruction::Shl:  return bitc::BINOP_SHL;
  98   case Instruction::LShr: return bitc::BINOP_LSHR;
  99   case Instruction::AShr: return bitc::BINOP_ASHR;
 100   case Instruction::And:  return bitc::BINOP_AND;
 101   case Instruction::Or:   return bitc::BINOP_OR;
 102   case Instruction::Xor:  return bitc::BINOP_XOR;
 103   }
 104 }
 105
 106 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 107   switch (Op) {
 108   default: llvm_unreachable("Unknown RMW operation!");
 109   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 110   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 111   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 112   case AtomicRMWInst::And: return bitc::RMW_AND;
 113   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 114   case AtomicRMWInst::Or: return bitc::RMW_OR;
 115   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 116   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 117   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 118   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 119   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 120   }
 121 }
 122
 123 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 124   switch (Ordering) {
 125   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 126   case Unordered: return bitc::ORDERING_UNORDERED;
 127   case Monotonic: return bitc::ORDERING_MONOTONIC;
 128   case Acquire: return bitc::ORDERING_ACQUIRE;
 129   case Release: return bitc::ORDERING_RELEASE;
 130   case AcquireRelease: return bitc::ORDERING_ACQREL;
 131   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 132   }
 133   llvm_unreachable("Invalid ordering");
 134 }
 135
 136 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 137   switch (SynchScope) {
 138   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 139   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 140   }
 141   llvm_unreachable("Invalid synch scope");
 142 }
 143
 144 static void WriteStringRecord(unsigned Code, StringRef Str,
 145                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 146   SmallVector<unsigned, 64> Vals;
 147
 148   // Code: [strchar x N]
 149   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 150     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 151       AbbrevToUse = 0;
 152     Vals.push_back(Str[i]);
 153   }
 154
 155   // Emit the finished record.
 156   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 157 }
 158
 159 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 160   switch (Kind) {
 161   case Attribute::Alignment:
 162     return bitc::ATTR_KIND_ALIGNMENT;
 163   case Attribute::AlwaysInline:
 164     return bitc::ATTR_KIND_ALWAYS_INLINE;
 165   case Attribute::Builtin:
 166     return bitc::ATTR_KIND_BUILTIN;
 167   case Attribute::ByVal:
 168     return bitc::ATTR_KIND_BY_VAL;
 169   case Attribute::Convergent:
 170     return bitc::ATTR_KIND_CONVERGENT;
 171   case Attribute::InAlloca:
 172     return bitc::ATTR_KIND_IN_ALLOCA;
 173   case Attribute::Cold:
 174     return bitc::ATTR_KIND_COLD;
 175   case Attribute::InlineHint:
 176     return bitc::ATTR_KIND_INLINE_HINT;
 177   case Attribute::InReg:
 178     return bitc::ATTR_KIND_IN_REG;
 179   case Attribute::JumpTable:
 180     return bitc::ATTR_KIND_JUMP_TABLE;
 181   case Attribute::MinSize:
 182     return bitc::ATTR_KIND_MIN_SIZE;
 183   case Attribute::Naked:
 184     return bitc::ATTR_KIND_NAKED;
 185   case Attribute::Nest:
 186     return bitc::ATTR_KIND_NEST;
 187   case Attribute::NoAlias:
 188     return bitc::ATTR_KIND_NO_ALIAS;
 189   case Attribute::NoBuiltin:
 190     return bitc::ATTR_KIND_NO_BUILTIN;
 191   case Attribute::NoCapture:
 192     return bitc::ATTR_KIND_NO_CAPTURE;
 193   case Attribute::NoDuplicate:
 194     return bitc::ATTR_KIND_NO_DUPLICATE;
 195   case Attribute::NoImplicitFloat:
 196     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 197   case Attribute::NoInline:
 198     return bitc::ATTR_KIND_NO_INLINE;
 199   case Attribute::NonLazyBind:
 200     return bitc::ATTR_KIND_NON_LAZY_BIND;
 201   case Attribute::NonNull:
 202     return bitc::ATTR_KIND_NON_NULL;
 203   case Attribute::Dereferenceable:
 204     return bitc::ATTR_KIND_DEREFERENCEABLE;
 205   case Attribute::DereferenceableOrNull:
 206     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 207   case Attribute::NoRedZone:
 208     return bitc::ATTR_KIND_NO_RED_ZONE;
 209   case Attribute::NoReturn:
 210     return bitc::ATTR_KIND_NO_RETURN;
 211   case Attribute::NoUnwind:
 212     return bitc::ATTR_KIND_NO_UNWIND;
 213   case Attribute::OptimizeForSize:
 214     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 215   case Attribute::OptimizeNone:
 216     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 217   case Attribute::ReadNone:
 218     return bitc::ATTR_KIND_READ_NONE;
 219   case Attribute::ReadOnly:
 220     return bitc::ATTR_KIND_READ_ONLY;
 221   case Attribute::Returned:
 222     return bitc::ATTR_KIND_RETURNED;
 223   case Attribute::ReturnsTwice:
 224     return bitc::ATTR_KIND_RETURNS_TWICE;
 225   case Attribute::SExt:
 226     return bitc::ATTR_KIND_S_EXT;
 227   case Attribute::StackAlignment:
 228     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 229   case Attribute::StackProtect:
 230     return bitc::ATTR_KIND_STACK_PROTECT;
 231   case Attribute::StackProtectReq:
 232     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 233   case Attribute::StackProtectStrong:
 234     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 235   case Attribute::StructRet:
 236     return bitc::ATTR_KIND_STRUCT_RET;
 237   case Attribute::SanitizeAddress:
 238     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 239   case Attribute::SanitizeThread:
 240     return bitc::ATTR_KIND_SANITIZE_THREAD;
 241   case Attribute::SanitizeMemory:
 242     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 243   case Attribute::UWTable:
 244     return bitc::ATTR_KIND_UW_TABLE;
 245   case Attribute::ZExt:
 246     return bitc::ATTR_KIND_Z_EXT;
 247   case Attribute::EndAttrKinds:
 248     llvm_unreachable("Can not encode end-attribute kinds marker.");
 249   case Attribute::None:
 250     llvm_unreachable("Can not encode none-attribute.");
 251   }
 252
 253   llvm_unreachable("Trying to encode unknown attribute");
 254 }
 255
 256 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 257                                      BitstreamWriter &Stream) {
 258   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 259   if (AttrGrps.empty()) return;
 260
 261   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 262
 263   SmallVector<uint64_t, 64> Record;
 264   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 265     AttributeSet AS = AttrGrps[i];
 266     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 267       AttributeSet A = AS.getSlotAttributes(i);
 268
 269       Record.push_back(VE.getAttributeGroupID(A));
 270       Record.push_back(AS.getSlotIndex(i));
 271
 272       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 273            I != E; ++I) {
 274         Attribute Attr = *I;
 275         if (Attr.isEnumAttribute()) {
 276           Record.push_back(0);
 277           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 278         } else if (Attr.isIntAttribute()) {
 279           Record.push_back(1);
 280           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 281           Record.push_back(Attr.getValueAsInt());
 282         } else {
 283           StringRef Kind = Attr.getKindAsString();
 284           StringRef Val = Attr.getValueAsString();
 285
 286           Record.push_back(Val.empty() ? 3 : 4);
 287           Record.append(Kind.begin(), Kind.end());
 288           Record.push_back(0);
 289           if (!Val.empty()) {
 290             Record.append(Val.begin(), Val.end());
 291             Record.push_back(0);
 292           }
 293         }
 294       }
 295
 296       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 297       Record.clear();
 298     }
 299   }
 300
 301   Stream.ExitBlock();
 302 }
 303
 304 static void WriteAttributeTable(const ValueEnumerator &VE,
 305                                 BitstreamWriter &Stream) {
 306   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 307   if (Attrs.empty()) return;
 308
 309   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 310
 311   SmallVector<uint64_t, 64> Record;
 312   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 313     const AttributeSet &A = Attrs[i];
 314     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 315       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 316
 317     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 318     Record.clear();
 319   }
 320
 321   Stream.ExitBlock();
 322 }
 323
 324 /// WriteTypeTable - Write out the type table for a module.
 325 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 326   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 327
 328   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 329   SmallVector<uint64_t, 64> TypeVals;
 330
 331   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 332
 333   // Abbrev for TYPE_CODE_POINTER.
 334   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 335   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 337   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 338   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 339
 340   // Abbrev for TYPE_CODE_FUNCTION.
 341   Abbv = new BitCodeAbbrev();
 342   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 344   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 346
 347   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 348
 349   // Abbrev for TYPE_CODE_STRUCT_ANON.
 350   Abbv = new BitCodeAbbrev();
 351   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 355
 356   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 357
 358   // Abbrev for TYPE_CODE_STRUCT_NAME.
 359   Abbv = new BitCodeAbbrev();
 360   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 363   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 364
 365   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 366   Abbv = new BitCodeAbbrev();
 367   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 369   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 371
 372   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 373
 374   // Abbrev for TYPE_CODE_ARRAY.
 375   Abbv = new BitCodeAbbrev();
 376   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 377   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 378   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 379
 380   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 381
 382   // Emit an entry count so the reader can reserve space.
 383   TypeVals.push_back(TypeList.size());
 384   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 385   TypeVals.clear();
 386
 387   // Loop over all of the types, emitting each in turn.
 388   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 389     Type *T = TypeList[i];
 390     int AbbrevToUse = 0;
 391     unsigned Code = 0;
 392
 393     switch (T->getTypeID()) {
 394     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 395     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 396     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 397     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 398     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 399     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 400     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 401     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 402     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 403     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 404     case Type::IntegerTyID:
 405       // INTEGER: [width]
 406       Code = bitc::TYPE_CODE_INTEGER;
 407       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 408       break;
 409     case Type::PointerTyID: {
 410       PointerType *PTy = cast<PointerType>(T);
 411       // POINTER: [pointee type, address space]
 412       Code = bitc::TYPE_CODE_POINTER;
 413       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 414       unsigned AddressSpace = PTy->getAddressSpace();
 415       TypeVals.push_back(AddressSpace);
 416       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 417       break;
 418     }
 419     case Type::FunctionTyID: {
 420       FunctionType *FT = cast<FunctionType>(T);
 421       // FUNCTION: [isvararg, retty, paramty x N]
 422       Code = bitc::TYPE_CODE_FUNCTION;
 423       TypeVals.push_back(FT->isVarArg());
 424       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 425       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 426         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 427       AbbrevToUse = FunctionAbbrev;
 428       break;
 429     }
 430     case Type::StructTyID: {
 431       StructType *ST = cast<StructType>(T);
 432       // STRUCT: [ispacked, eltty x N]
 433       TypeVals.push_back(ST->isPacked());
 434       // Output all of the element types.
 435       for (StructType::element_iterator I = ST->element_begin(),
 436            E = ST->element_end(); I != E; ++I)
 437         TypeVals.push_back(VE.getTypeID(*I));
 438
 439       if (ST->isLiteral()) {
 440         Code = bitc::TYPE_CODE_STRUCT_ANON;
 441         AbbrevToUse = StructAnonAbbrev;
 442       } else {
 443         if (ST->isOpaque()) {
 444           Code = bitc::TYPE_CODE_OPAQUE;
 445         } else {
 446           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 447           AbbrevToUse = StructNamedAbbrev;
 448         }
 449
 450         // Emit the name if it is present.
 451         if (!ST->getName().empty())
 452           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 453                             StructNameAbbrev, Stream);
 454       }
 455       break;
 456     }
 457     case Type::ArrayTyID: {
 458       ArrayType *AT = cast<ArrayType>(T);
 459       // ARRAY: [numelts, eltty]
 460       Code = bitc::TYPE_CODE_ARRAY;
 461       TypeVals.push_back(AT->getNumElements());
 462       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 463       AbbrevToUse = ArrayAbbrev;
 464       break;
 465     }
 466     case Type::VectorTyID: {
 467       VectorType *VT = cast<VectorType>(T);
 468       // VECTOR [numelts, eltty]
 469       Code = bitc::TYPE_CODE_VECTOR;
 470       TypeVals.push_back(VT->getNumElements());
 471       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 472       break;
 473     }
 474     }
 475
 476     // Emit the finished record.
 477     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 478     TypeVals.clear();
 479   }
 480
 481   Stream.ExitBlock();
 482 }
 483
 484 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 485   switch (GV.getLinkage()) {
 486   case GlobalValue::ExternalLinkage:
 487     return 0;
 488   case GlobalValue::WeakAnyLinkage:
 489     return 16;
 490   case GlobalValue::AppendingLinkage:
 491     return 2;
 492   case GlobalValue::InternalLinkage:
 493     return 3;
 494   case GlobalValue::LinkOnceAnyLinkage:
 495     return 18;
 496   case GlobalValue::ExternalWeakLinkage:
 497     return 7;
 498   case GlobalValue::CommonLinkage:
 499     return 8;
 500   case GlobalValue::PrivateLinkage:
 501     return 9;
 502   case GlobalValue::WeakODRLinkage:
 503     return 17;
 504   case GlobalValue::LinkOnceODRLinkage:
 505     return 19;
 506   case GlobalValue::AvailableExternallyLinkage:
 507     return 12;
 508   }
 509   llvm_unreachable("Invalid linkage");
 510 }
 511
 512 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 513   switch (GV.getVisibility()) {
 514   case GlobalValue::DefaultVisibility:   return 0;
 515   case GlobalValue::HiddenVisibility:    return 1;
 516   case GlobalValue::ProtectedVisibility: return 2;
 517   }
 518   llvm_unreachable("Invalid visibility");
 519 }
 520
 521 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 522   switch (GV.getDLLStorageClass()) {
 523   case GlobalValue::DefaultStorageClass:   return 0;
 524   case GlobalValue::DLLImportStorageClass: return 1;
 525   case GlobalValue::DLLExportStorageClass: return 2;
 526   }
 527   llvm_unreachable("Invalid DLL storage class");
 528 }
 529
 530 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 531   switch (GV.getThreadLocalMode()) {
 532     case GlobalVariable::NotThreadLocal:         return 0;
 533     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 534     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 535     case GlobalVariable::InitialExecTLSModel:    return 3;
 536     case GlobalVariable::LocalExecTLSModel:      return 4;
 537   }
 538   llvm_unreachable("Invalid TLS model");
 539 }
 540
 541 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 542   switch (C.getSelectionKind()) {
 543   case Comdat::Any:
 544     return bitc::COMDAT_SELECTION_KIND_ANY;
 545   case Comdat::ExactMatch:
 546     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 547   case Comdat::Largest:
 548     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 549   case Comdat::NoDuplicates:
 550     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 551   case Comdat::SameSize:
 552     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 553   }
 554   llvm_unreachable("Invalid selection kind");
 555 }
 556
 557 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 558   SmallVector<uint16_t, 64> Vals;
 559   for (const Comdat *C : VE.getComdats()) {
 560     // COMDAT: [selection_kind, name]
 561     Vals.push_back(getEncodedComdatSelectionKind(*C));
 562     size_t Size = C->getName().size();
 563     assert(isUInt<16>(Size));
 564     Vals.push_back(Size);
 565     for (char Chr : C->getName())
 566       Vals.push_back((unsigned char)Chr);
 567     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 568     Vals.clear();
 569   }
 570 }
 571
 572 // Emit top-level description of module, including target triple, inline asm,
 573 // descriptors for global variables, and function prototype info.
 574 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 575                             BitstreamWriter &Stream) {
 576   // Emit various pieces of data attached to a module.
 577   if (!M->getTargetTriple().empty())
 578     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 579                       0/*TODO*/, Stream);
 580   const std::string &DL = M->getDataLayoutStr();
 581   if (!DL.empty())
 582     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 583   if (!M->getModuleInlineAsm().empty())
 584     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 585                       0/*TODO*/, Stream);
 586
 587   // Emit information about sections and GC, computing how many there are. Also
 588   // compute the maximum alignment value.
 589   std::map<std::string, unsigned> SectionMap;
 590   std::map<std::string, unsigned> GCMap;
 591   unsigned MaxAlignment = 0;
 592   unsigned MaxGlobalType = 0;
 593   for (const GlobalValue &GV : M->globals()) {
 594     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 595     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
 596     if (GV.hasSection()) {
 597       // Give section names unique ID's.
 598       unsigned &Entry = SectionMap[GV.getSection()];
 599       if (!Entry) {
 600         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 601                           0/*TODO*/, Stream);
 602         Entry = SectionMap.size();
 603       }
 604     }
 605   }
 606   for (const Function &F : *M) {
 607     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 608     if (F.hasSection()) {
 609       // Give section names unique ID's.
 610       unsigned &Entry = SectionMap[F.getSection()];
 611       if (!Entry) {
 612         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 613                           0/*TODO*/, Stream);
 614         Entry = SectionMap.size();
 615       }
 616     }
 617     if (F.hasGC()) {
 618       // Same for GC names.
 619       unsigned &Entry = GCMap[F.getGC()];
 620       if (!Entry) {
 621         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 622                           0/*TODO*/, Stream);
 623         Entry = GCMap.size();
 624       }
 625     }
 626   }
 627
 628   // Emit abbrev for globals, now that we know # sections and max alignment.
 629   unsigned SimpleGVarAbbrev = 0;
 630   if (!M->global_empty()) {
 631     // Add an abbrev for common globals with no visibility or thread localness.
 632     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 633     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 635                               Log2_32_Ceil(MaxGlobalType+1)));
 636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
 637                                                            //| explicitType << 1
 638                                                            //| constant
 639     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
 640     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
 641     if (MaxAlignment == 0)                                 // Alignment.
 642       Abbv->Add(BitCodeAbbrevOp(0));
 643     else {
 644       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 645       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 646                                Log2_32_Ceil(MaxEncAlignment+1)));
 647     }
 648     if (SectionMap.empty())                                    // Section.
 649       Abbv->Add(BitCodeAbbrevOp(0));
 650     else
 651       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 652                                Log2_32_Ceil(SectionMap.size()+1)));
 653     // Don't bother emitting vis + thread local.
 654     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 655   }
 656
 657   // Emit the global variable information.
 658   SmallVector<unsigned, 64> Vals;
 659   for (const GlobalVariable &GV : M->globals()) {
 660     unsigned AbbrevToUse = 0;
 661
 662     // GLOBALVAR: [type, isconst, initid,
 663     //             linkage, alignment, section, visibility, threadlocal,
 664     //             unnamed_addr, externally_initialized, dllstorageclass,
 665     //             comdat]
 666     Vals.push_back(VE.getTypeID(GV.getValueType()));
 667     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
 668     Vals.push_back(GV.isDeclaration() ? 0 :
 669                    (VE.getValueID(GV.getInitializer()) + 1));
 670     Vals.push_back(getEncodedLinkage(GV));
 671     Vals.push_back(Log2_32(GV.getAlignment())+1);
 672     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 673     if (GV.isThreadLocal() ||
 674         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 675         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 676         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 677         GV.hasComdat()) {
 678       Vals.push_back(getEncodedVisibility(GV));
 679       Vals.push_back(getEncodedThreadLocalMode(GV));
 680       Vals.push_back(GV.hasUnnamedAddr());
 681       Vals.push_back(GV.isExternallyInitialized());
 682       Vals.push_back(getEncodedDLLStorageClass(GV));
 683       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 684     } else {
 685       AbbrevToUse = SimpleGVarAbbrev;
 686     }
 687
 688     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 689     Vals.clear();
 690   }
 691
 692   // Emit the function proto information.
 693   for (const Function &F : *M) {
 694     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 695     //             section, visibility, gc, unnamed_addr, prologuedata,
 696     //             dllstorageclass, comdat, prefixdata]
 697     Vals.push_back(VE.getTypeID(F.getFunctionType()));
 698     Vals.push_back(F.getCallingConv());
 699     Vals.push_back(F.isDeclaration());
 700     Vals.push_back(getEncodedLinkage(F));
 701     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 702     Vals.push_back(Log2_32(F.getAlignment())+1);
 703     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 704     Vals.push_back(getEncodedVisibility(F));
 705     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 706     Vals.push_back(F.hasUnnamedAddr());
 707     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 708                                        : 0);
 709     Vals.push_back(getEncodedDLLStorageClass(F));
 710     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 711     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 712                                      : 0);
 713
 714     unsigned AbbrevToUse = 0;
 715     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 716     Vals.clear();
 717   }
 718
 719   // Emit the alias information.
 720   for (const GlobalAlias &A : M->aliases()) {
 721     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 722     Vals.push_back(VE.getTypeID(A.getType()));
 723     Vals.push_back(VE.getValueID(A.getAliasee()));
 724     Vals.push_back(getEncodedLinkage(A));
 725     Vals.push_back(getEncodedVisibility(A));
 726     Vals.push_back(getEncodedDLLStorageClass(A));
 727     Vals.push_back(getEncodedThreadLocalMode(A));
 728     Vals.push_back(A.hasUnnamedAddr());
 729     unsigned AbbrevToUse = 0;
 730     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 731     Vals.clear();
 732   }
 733 }
 734
 735 static uint64_t GetOptimizationFlags(const Value *V) {
 736   uint64_t Flags = 0;
 737
 738   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 739     if (OBO->hasNoSignedWrap())
 740       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 741     if (OBO->hasNoUnsignedWrap())
 742       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 743   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 744     if (PEO->isExact())
 745       Flags |= 1 << bitc::PEO_EXACT;
 746   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 747     if (FPMO->hasUnsafeAlgebra())
 748       Flags |= FastMathFlags::UnsafeAlgebra;
 749     if (FPMO->hasNoNaNs())
 750       Flags |= FastMathFlags::NoNaNs;
 751     if (FPMO->hasNoInfs())
 752       Flags |= FastMathFlags::NoInfs;
 753     if (FPMO->hasNoSignedZeros())
 754       Flags |= FastMathFlags::NoSignedZeros;
 755     if (FPMO->hasAllowReciprocal())
 756       Flags |= FastMathFlags::AllowReciprocal;
 757   }
 758
 759   return Flags;
 760 }
 761
 762 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 763                                  const ValueEnumerator &VE,
 764                                  BitstreamWriter &Stream,
 765                                  SmallVectorImpl<uint64_t> &Record) {
 766   // Mimic an MDNode with a value as one operand.
 767   Value *V = MD->getValue();
 768   Record.push_back(VE.getTypeID(V->getType()));
 769   Record.push_back(VE.getValueID(V));
 770   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 771   Record.clear();
 772 }
 773
 774 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 775                          BitstreamWriter &Stream,
 776                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 777   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 778     Metadata *MD = N->getOperand(i);
 779     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 780            "Unexpected function-local metadata");
 781     Record.push_back(VE.getMetadataOrNullID(MD));
 782   }
 783   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 784                                     : bitc::METADATA_NODE,
 785                     Record, Abbrev);
 786   Record.clear();
 787 }
 788
 789 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 790                             BitstreamWriter &Stream,
 791                             SmallVectorImpl<uint64_t> &Record,
 792                             unsigned Abbrev) {
 793   Record.push_back(N->isDistinct());
 794   Record.push_back(N->getLine());
 795   Record.push_back(N->getColumn());
 796   Record.push_back(VE.getMetadataID(N->getScope()));
 797   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 798
 799   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 800   Record.clear();
 801 }
 802
 803 static void WriteGenericDINode(const GenericDINode *N,
 804                                const ValueEnumerator &VE,
 805                                BitstreamWriter &Stream,
 806                                SmallVectorImpl<uint64_t> &Record,
 807                                unsigned Abbrev) {
 808   Record.push_back(N->isDistinct());
 809   Record.push_back(N->getTag());
 810   Record.push_back(0); // Per-tag version field; unused for now.
 811
 812   for (auto &I : N->operands())
 813     Record.push_back(VE.getMetadataOrNullID(I));
 814
 815   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 816   Record.clear();
 817 }
 818
 819 static uint64_t rotateSign(int64_t I) {
 820   uint64_t U = I;
 821   return I < 0 ? ~(U << 1) : U << 1;
 822 }
 823
 824 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 825                             BitstreamWriter &Stream,
 826                             SmallVectorImpl<uint64_t> &Record,
 827                             unsigned Abbrev) {
 828   Record.push_back(N->isDistinct());
 829   Record.push_back(N->getCount());
 830   Record.push_back(rotateSign(N->getLowerBound()));
 831
 832   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 833   Record.clear();
 834 }
 835
 836 static void WriteDIEnumerator(const DIEnumerator *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(rotateSign(N->getValue()));
 842   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 843
 844   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 845   Record.clear();
 846 }
 847
 848 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 849                              BitstreamWriter &Stream,
 850                              SmallVectorImpl<uint64_t> &Record,
 851                              unsigned Abbrev) {
 852   Record.push_back(N->isDistinct());
 853   Record.push_back(N->getTag());
 854   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 855   Record.push_back(N->getSizeInBits());
 856   Record.push_back(N->getAlignInBits());
 857   Record.push_back(N->getEncoding());
 858
 859   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 860   Record.clear();
 861 }
 862
 863 static void WriteDIDerivedType(const DIDerivedType *N,
 864                                const ValueEnumerator &VE,
 865                                BitstreamWriter &Stream,
 866                                SmallVectorImpl<uint64_t> &Record,
 867                                unsigned Abbrev) {
 868   Record.push_back(N->isDistinct());
 869   Record.push_back(N->getTag());
 870   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 871   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 872   Record.push_back(N->getLine());
 873   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 874   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 875   Record.push_back(N->getSizeInBits());
 876   Record.push_back(N->getAlignInBits());
 877   Record.push_back(N->getOffsetInBits());
 878   Record.push_back(N->getFlags());
 879   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 880
 881   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 882   Record.clear();
 883 }
 884
 885 static void WriteDICompositeType(const DICompositeType *N,
 886                                  const ValueEnumerator &VE,
 887                                  BitstreamWriter &Stream,
 888                                  SmallVectorImpl<uint64_t> &Record,
 889                                  unsigned Abbrev) {
 890   Record.push_back(N->isDistinct());
 891   Record.push_back(N->getTag());
 892   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 893   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 894   Record.push_back(N->getLine());
 895   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 896   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 897   Record.push_back(N->getSizeInBits());
 898   Record.push_back(N->getAlignInBits());
 899   Record.push_back(N->getOffsetInBits());
 900   Record.push_back(N->getFlags());
 901   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 902   Record.push_back(N->getRuntimeLang());
 903   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 904   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 905   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 906
 907   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 908   Record.clear();
 909 }
 910
 911 static void WriteDISubroutineType(const DISubroutineType *N,
 912                                   const ValueEnumerator &VE,
 913                                   BitstreamWriter &Stream,
 914                                   SmallVectorImpl<uint64_t> &Record,
 915                                   unsigned Abbrev) {
 916   Record.push_back(N->isDistinct());
 917   Record.push_back(N->getFlags());
 918   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 919
 920   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 921   Record.clear();
 922 }
 923
 924 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 925                         BitstreamWriter &Stream,
 926                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 927   Record.push_back(N->isDistinct());
 928   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 929   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 930
 931   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 932   Record.clear();
 933 }
 934
 935 static void WriteDICompileUnit(const DICompileUnit *N,
 936                                const ValueEnumerator &VE,
 937                                BitstreamWriter &Stream,
 938                                SmallVectorImpl<uint64_t> &Record,
 939                                unsigned Abbrev) {
 940   Record.push_back(N->isDistinct());
 941   Record.push_back(N->getSourceLanguage());
 942   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 943   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 944   Record.push_back(N->isOptimized());
 945   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 946   Record.push_back(N->getRuntimeVersion());
 947   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 948   Record.push_back(N->getEmissionKind());
 949   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 950   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 951   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 952   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
 953   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
 954   Record.push_back(N->getDWOId());
 955
 956   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 957   Record.clear();
 958 }
 959
 960 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
 961                               BitstreamWriter &Stream,
 962                               SmallVectorImpl<uint64_t> &Record,
 963                               unsigned Abbrev) {
 964   Record.push_back(N->isDistinct());
 965   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 966   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 967   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 968   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 969   Record.push_back(N->getLine());
 970   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 971   Record.push_back(N->isLocalToUnit());
 972   Record.push_back(N->isDefinition());
 973   Record.push_back(N->getScopeLine());
 974   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 975   Record.push_back(N->getVirtuality());
 976   Record.push_back(N->getVirtualIndex());
 977   Record.push_back(N->getFlags());
 978   Record.push_back(N->isOptimized());
 979   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
 980   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 981   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 982   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
 983
 984   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 985   Record.clear();
 986 }
 987
 988 static void WriteDILexicalBlock(const DILexicalBlock *N,
 989                                 const ValueEnumerator &VE,
 990                                 BitstreamWriter &Stream,
 991                                 SmallVectorImpl<uint64_t> &Record,
 992                                 unsigned Abbrev) {
 993   Record.push_back(N->isDistinct());
 994   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 995   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 996   Record.push_back(N->getLine());
 997   Record.push_back(N->getColumn());
 998
 999   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1000   Record.clear();
1001 }
1002
1003 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1004                                     const ValueEnumerator &VE,
1005                                     BitstreamWriter &Stream,
1006                                     SmallVectorImpl<uint64_t> &Record,
1007                                     unsigned Abbrev) {
1008   Record.push_back(N->isDistinct());
1009   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1010   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1011   Record.push_back(N->getDiscriminator());
1012
1013   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1014   Record.clear();
1015 }
1016
1017 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1018                              BitstreamWriter &Stream,
1019                              SmallVectorImpl<uint64_t> &Record,
1020                              unsigned Abbrev) {
1021   Record.push_back(N->isDistinct());
1022   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1023   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1024   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1025   Record.push_back(N->getLine());
1026
1027   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1028   Record.clear();
1029 }
1030
1031 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1032                                          const ValueEnumerator &VE,
1033                                          BitstreamWriter &Stream,
1034                                          SmallVectorImpl<uint64_t> &Record,
1035                                          unsigned Abbrev) {
1036   Record.push_back(N->isDistinct());
1037   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1038   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1039
1040   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1041   Record.clear();
1042 }
1043
1044 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1045                                           const ValueEnumerator &VE,
1046                                           BitstreamWriter &Stream,
1047                                           SmallVectorImpl<uint64_t> &Record,
1048                                           unsigned Abbrev) {
1049   Record.push_back(N->isDistinct());
1050   Record.push_back(N->getTag());
1051   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1052   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1053   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1054
1055   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1056   Record.clear();
1057 }
1058
1059 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1060                                   const ValueEnumerator &VE,
1061                                   BitstreamWriter &Stream,
1062                                   SmallVectorImpl<uint64_t> &Record,
1063                                   unsigned Abbrev) {
1064   Record.push_back(N->isDistinct());
1065   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1066   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1067   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1068   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1069   Record.push_back(N->getLine());
1070   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1071   Record.push_back(N->isLocalToUnit());
1072   Record.push_back(N->isDefinition());
1073   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1074   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1075
1076   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1077   Record.clear();
1078 }
1079
1080 static void WriteDILocalVariable(const DILocalVariable *N,
1081                                  const ValueEnumerator &VE,
1082                                  BitstreamWriter &Stream,
1083                                  SmallVectorImpl<uint64_t> &Record,
1084                                  unsigned Abbrev) {
1085   Record.push_back(N->isDistinct());
1086   Record.push_back(N->getTag());
1087   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1088   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1089   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1090   Record.push_back(N->getLine());
1091   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1092   Record.push_back(N->getArg());
1093   Record.push_back(N->getFlags());
1094
1095   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1096   Record.clear();
1097 }
1098
1099 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1100                               BitstreamWriter &Stream,
1101                               SmallVectorImpl<uint64_t> &Record,
1102                               unsigned Abbrev) {
1103   Record.reserve(N->getElements().size() + 1);
1104
1105   Record.push_back(N->isDistinct());
1106   Record.append(N->elements_begin(), N->elements_end());
1107
1108   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1109   Record.clear();
1110 }
1111
1112 static void WriteDIObjCProperty(const DIObjCProperty *N,
1113                                 const ValueEnumerator &VE,
1114                                 BitstreamWriter &Stream,
1115                                 SmallVectorImpl<uint64_t> &Record,
1116                                 unsigned Abbrev) {
1117   Record.push_back(N->isDistinct());
1118   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1119   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1120   Record.push_back(N->getLine());
1121   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1122   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1123   Record.push_back(N->getAttributes());
1124   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1125
1126   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1127   Record.clear();
1128 }
1129
1130 static void WriteDIImportedEntity(const DIImportedEntity *N,
1131                                   const ValueEnumerator &VE,
1132                                   BitstreamWriter &Stream,
1133                                   SmallVectorImpl<uint64_t> &Record,
1134                                   unsigned Abbrev) {
1135   Record.push_back(N->isDistinct());
1136   Record.push_back(N->getTag());
1137   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1138   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1139   Record.push_back(N->getLine());
1140   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1141
1142   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1143   Record.clear();
1144 }
1145
1146 static void WriteModuleMetadata(const Module *M,
1147                                 const ValueEnumerator &VE,
1148                                 BitstreamWriter &Stream) {
1149   const auto &MDs = VE.getMDs();
1150   if (MDs.empty() && M->named_metadata_empty())
1151     return;
1152
1153   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1154
1155   unsigned MDSAbbrev = 0;
1156   if (VE.hasMDString()) {
1157     // Abbrev for METADATA_STRING.
1158     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1159     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1161     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1162     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1163   }
1164
1165   // Initialize MDNode abbreviations.
1166 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1167 #include "llvm/IR/Metadata.def"
1168
1169   if (VE.hasDILocation()) {
1170     // Abbrev for METADATA_LOCATION.
1171     //
1172     // Assume the column is usually under 128, and always output the inlined-at
1173     // location (it's never more expensive than building an array size 1).
1174     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1175     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1179     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1181     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1182   }
1183
1184   if (VE.hasGenericDINode()) {
1185     // Abbrev for METADATA_GENERIC_DEBUG.
1186     //
1187     // Assume the column is usually under 128, and always output the inlined-at
1188     // location (it's never more expensive than building an array size 1).
1189     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1190     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1196     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1197     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1198   }
1199
1200   unsigned NameAbbrev = 0;
1201   if (!M->named_metadata_empty()) {
1202     // Abbrev for METADATA_NAME.
1203     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1204     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1206     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1207     NameAbbrev = Stream.EmitAbbrev(Abbv);
1208   }
1209
1210   SmallVector<uint64_t, 64> Record;
1211   for (const Metadata *MD : MDs) {
1212     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1213       assert(N->isResolved() && "Expected forward references to be resolved");
1214
1215       switch (N->getMetadataID()) {
1216       default:
1217         llvm_unreachable("Invalid MDNode subclass");
1218 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1219   case Metadata::CLASS##Kind:                                                  \
1220     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1221     continue;
1222 #include "llvm/IR/Metadata.def"
1223       }
1224     }
1225     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1226       WriteValueAsMetadata(MDC, VE, Stream, Record);
1227       continue;
1228     }
1229     const MDString *MDS = cast<MDString>(MD);
1230     // Code: [strchar x N]
1231     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1232
1233     // Emit the finished record.
1234     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1235     Record.clear();
1236   }
1237
1238   // Write named metadata.
1239   for (const NamedMDNode &NMD : M->named_metadata()) {
1240     // Write name.
1241     StringRef Str = NMD.getName();
1242     Record.append(Str.bytes_begin(), Str.bytes_end());
1243     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1244     Record.clear();
1245
1246     // Write named metadata operands.
1247     for (const MDNode *N : NMD.operands())
1248       Record.push_back(VE.getMetadataID(N));
1249     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1250     Record.clear();
1251   }
1252
1253   Stream.ExitBlock();
1254 }
1255
1256 static void WriteFunctionLocalMetadata(const Function &F,
1257                                        const ValueEnumerator &VE,
1258                                        BitstreamWriter &Stream) {
1259   bool StartedMetadataBlock = false;
1260   SmallVector<uint64_t, 64> Record;
1261   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1262       VE.getFunctionLocalMDs();
1263   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1264     assert(MDs[i] && "Expected valid function-local metadata");
1265     if (!StartedMetadataBlock) {
1266       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1267       StartedMetadataBlock = true;
1268     }
1269     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1270   }
1271
1272   if (StartedMetadataBlock)
1273     Stream.ExitBlock();
1274 }
1275
1276 static void WriteMetadataAttachment(const Function &F,
1277                                     const ValueEnumerator &VE,
1278                                     BitstreamWriter &Stream) {
1279   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1280
1281   SmallVector<uint64_t, 64> Record;
1282
1283   // Write metadata attachments
1284   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1285   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1286   F.getAllMetadata(MDs);
1287   if (!MDs.empty()) {
1288     for (const auto &I : MDs) {
1289       Record.push_back(I.first);
1290       Record.push_back(VE.getMetadataID(I.second));
1291     }
1292     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1293     Record.clear();
1294   }
1295
1296   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1297     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1298          I != E; ++I) {
1299       MDs.clear();
1300       I->getAllMetadataOtherThanDebugLoc(MDs);
1301
1302       // If no metadata, ignore instruction.
1303       if (MDs.empty()) continue;
1304
1305       Record.push_back(VE.getInstructionID(I));
1306
1307       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1308         Record.push_back(MDs[i].first);
1309         Record.push_back(VE.getMetadataID(MDs[i].second));
1310       }
1311       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1312       Record.clear();
1313     }
1314
1315   Stream.ExitBlock();
1316 }
1317
1318 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1319   SmallVector<uint64_t, 64> Record;
1320
1321   // Write metadata kinds
1322   // METADATA_KIND - [n x [id, name]]
1323   SmallVector<StringRef, 8> Names;
1324   M->getMDKindNames(Names);
1325
1326   if (Names.empty()) return;
1327
1328   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1329
1330   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1331     Record.push_back(MDKindID);
1332     StringRef KName = Names[MDKindID];
1333     Record.append(KName.begin(), KName.end());
1334
1335     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1336     Record.clear();
1337   }
1338
1339   Stream.ExitBlock();
1340 }
1341
1342 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1343   if ((int64_t)V >= 0)
1344     Vals.push_back(V << 1);
1345   else
1346     Vals.push_back((-V << 1) | 1);
1347 }
1348
1349 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1350                            const ValueEnumerator &VE,
1351                            BitstreamWriter &Stream, bool isGlobal) {
1352   if (FirstVal == LastVal) return;
1353
1354   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1355
1356   unsigned AggregateAbbrev = 0;
1357   unsigned String8Abbrev = 0;
1358   unsigned CString7Abbrev = 0;
1359   unsigned CString6Abbrev = 0;
1360   // If this is a constant pool for the module, emit module-specific abbrevs.
1361   if (isGlobal) {
1362     // Abbrev for CST_CODE_AGGREGATE.
1363     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1364     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1367     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1368
1369     // Abbrev for CST_CODE_STRING.
1370     Abbv = new BitCodeAbbrev();
1371     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1374     String8Abbrev = Stream.EmitAbbrev(Abbv);
1375     // Abbrev for CST_CODE_CSTRING.
1376     Abbv = new BitCodeAbbrev();
1377     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1380     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1381     // Abbrev for CST_CODE_CSTRING.
1382     Abbv = new BitCodeAbbrev();
1383     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1386     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1387   }
1388
1389   SmallVector<uint64_t, 64> Record;
1390
1391   const ValueEnumerator::ValueList &Vals = VE.getValues();
1392   Type *LastTy = nullptr;
1393   for (unsigned i = FirstVal; i != LastVal; ++i) {
1394     const Value *V = Vals[i].first;
1395     // If we need to switch types, do so now.
1396     if (V->getType() != LastTy) {
1397       LastTy = V->getType();
1398       Record.push_back(VE.getTypeID(LastTy));
1399       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1400                         CONSTANTS_SETTYPE_ABBREV);
1401       Record.clear();
1402     }
1403
1404     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1405       Record.push_back(unsigned(IA->hasSideEffects()) |
1406                        unsigned(IA->isAlignStack()) << 1 |
1407                        unsigned(IA->getDialect()&1) << 2);
1408
1409       // Add the asm string.
1410       const std::string &AsmStr = IA->getAsmString();
1411       Record.push_back(AsmStr.size());
1412       Record.append(AsmStr.begin(), AsmStr.end());
1413
1414       // Add the constraint string.
1415       const std::string &ConstraintStr = IA->getConstraintString();
1416       Record.push_back(ConstraintStr.size());
1417       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1418       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1419       Record.clear();
1420       continue;
1421     }
1422     const Constant *C = cast<Constant>(V);
1423     unsigned Code = -1U;
1424     unsigned AbbrevToUse = 0;
1425     if (C->isNullValue()) {
1426       Code = bitc::CST_CODE_NULL;
1427     } else if (isa<UndefValue>(C)) {
1428       Code = bitc::CST_CODE_UNDEF;
1429     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1430       if (IV->getBitWidth() <= 64) {
1431         uint64_t V = IV->getSExtValue();
1432         emitSignedInt64(Record, V);
1433         Code = bitc::CST_CODE_INTEGER;
1434         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1435       } else {                             // Wide integers, > 64 bits in size.
1436         // We have an arbitrary precision integer value to write whose
1437         // bit width is > 64. However, in canonical unsigned integer
1438         // format it is likely that the high bits are going to be zero.
1439         // So, we only write the number of active words.
1440         unsigned NWords = IV->getValue().getActiveWords();
1441         const uint64_t *RawWords = IV->getValue().getRawData();
1442         for (unsigned i = 0; i != NWords; ++i) {
1443           emitSignedInt64(Record, RawWords[i]);
1444         }
1445         Code = bitc::CST_CODE_WIDE_INTEGER;
1446       }
1447     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1448       Code = bitc::CST_CODE_FLOAT;
1449       Type *Ty = CFP->getType();
1450       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1451         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1452       } else if (Ty->isX86_FP80Ty()) {
1453         // api needed to prevent premature destruction
1454         // bits are not in the same order as a normal i80 APInt, compensate.
1455         APInt api = CFP->getValueAPF().bitcastToAPInt();
1456         const uint64_t *p = api.getRawData();
1457         Record.push_back((p[1] << 48) | (p[0] >> 16));
1458         Record.push_back(p[0] & 0xffffLL);
1459       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1460         APInt api = CFP->getValueAPF().bitcastToAPInt();
1461         const uint64_t *p = api.getRawData();
1462         Record.push_back(p[0]);
1463         Record.push_back(p[1]);
1464       } else {
1465         assert (0 && "Unknown FP type!");
1466       }
1467     } else if (isa<ConstantDataSequential>(C) &&
1468                cast<ConstantDataSequential>(C)->isString()) {
1469       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1470       // Emit constant strings specially.
1471       unsigned NumElts = Str->getNumElements();
1472       // If this is a null-terminated string, use the denser CSTRING encoding.
1473       if (Str->isCString()) {
1474         Code = bitc::CST_CODE_CSTRING;
1475         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1476       } else {
1477         Code = bitc::CST_CODE_STRING;
1478         AbbrevToUse = String8Abbrev;
1479       }
1480       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1481       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1482       for (unsigned i = 0; i != NumElts; ++i) {
1483         unsigned char V = Str->getElementAsInteger(i);
1484         Record.push_back(V);
1485         isCStr7 &= (V & 128) == 0;
1486         if (isCStrChar6)
1487           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1488       }
1489
1490       if (isCStrChar6)
1491         AbbrevToUse = CString6Abbrev;
1492       else if (isCStr7)
1493         AbbrevToUse = CString7Abbrev;
1494     } else if (const ConstantDataSequential *CDS =
1495                   dyn_cast<ConstantDataSequential>(C)) {
1496       Code = bitc::CST_CODE_DATA;
1497       Type *EltTy = CDS->getType()->getElementType();
1498       if (isa<IntegerType>(EltTy)) {
1499         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1500           Record.push_back(CDS->getElementAsInteger(i));
1501       } else if (EltTy->isFloatTy()) {
1502         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1503           union { float F; uint32_t I; };
1504           F = CDS->getElementAsFloat(i);
1505           Record.push_back(I);
1506         }
1507       } else {
1508         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1509         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1510           union { double F; uint64_t I; };
1511           F = CDS->getElementAsDouble(i);
1512           Record.push_back(I);
1513         }
1514       }
1515     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1516                isa<ConstantVector>(C)) {
1517       Code = bitc::CST_CODE_AGGREGATE;
1518       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1519         Record.push_back(VE.getValueID(C->getOperand(i)));
1520       AbbrevToUse = AggregateAbbrev;
1521     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1522       switch (CE->getOpcode()) {
1523       default:
1524         if (Instruction::isCast(CE->getOpcode())) {
1525           Code = bitc::CST_CODE_CE_CAST;
1526           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1527           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1528           Record.push_back(VE.getValueID(C->getOperand(0)));
1529           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1530         } else {
1531           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1532           Code = bitc::CST_CODE_CE_BINOP;
1533           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1534           Record.push_back(VE.getValueID(C->getOperand(0)));
1535           Record.push_back(VE.getValueID(C->getOperand(1)));
1536           uint64_t Flags = GetOptimizationFlags(CE);
1537           if (Flags != 0)
1538             Record.push_back(Flags);
1539         }
1540         break;
1541       case Instruction::GetElementPtr: {
1542         Code = bitc::CST_CODE_CE_GEP;
1543         const auto *GO = cast<GEPOperator>(C);
1544         if (GO->isInBounds())
1545           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1546         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1547         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1548           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1549           Record.push_back(VE.getValueID(C->getOperand(i)));
1550         }
1551         break;
1552       }
1553       case Instruction::Select:
1554         Code = bitc::CST_CODE_CE_SELECT;
1555         Record.push_back(VE.getValueID(C->getOperand(0)));
1556         Record.push_back(VE.getValueID(C->getOperand(1)));
1557         Record.push_back(VE.getValueID(C->getOperand(2)));
1558         break;
1559       case Instruction::ExtractElement:
1560         Code = bitc::CST_CODE_CE_EXTRACTELT;
1561         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1562         Record.push_back(VE.getValueID(C->getOperand(0)));
1563         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1564         Record.push_back(VE.getValueID(C->getOperand(1)));
1565         break;
1566       case Instruction::InsertElement:
1567         Code = bitc::CST_CODE_CE_INSERTELT;
1568         Record.push_back(VE.getValueID(C->getOperand(0)));
1569         Record.push_back(VE.getValueID(C->getOperand(1)));
1570         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1571         Record.push_back(VE.getValueID(C->getOperand(2)));
1572         break;
1573       case Instruction::ShuffleVector:
1574         // If the return type and argument types are the same, this is a
1575         // standard shufflevector instruction.  If the types are different,
1576         // then the shuffle is widening or truncating the input vectors, and
1577         // the argument type must also be encoded.
1578         if (C->getType() == C->getOperand(0)->getType()) {
1579           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1580         } else {
1581           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1582           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1583         }
1584         Record.push_back(VE.getValueID(C->getOperand(0)));
1585         Record.push_back(VE.getValueID(C->getOperand(1)));
1586         Record.push_back(VE.getValueID(C->getOperand(2)));
1587         break;
1588       case Instruction::ICmp:
1589       case Instruction::FCmp:
1590         Code = bitc::CST_CODE_CE_CMP;
1591         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1592         Record.push_back(VE.getValueID(C->getOperand(0)));
1593         Record.push_back(VE.getValueID(C->getOperand(1)));
1594         Record.push_back(CE->getPredicate());
1595         break;
1596       }
1597     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1598       Code = bitc::CST_CODE_BLOCKADDRESS;
1599       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1600       Record.push_back(VE.getValueID(BA->getFunction()));
1601       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1602     } else {
1603 #ifndef NDEBUG
1604       C->dump();
1605 #endif
1606       llvm_unreachable("Unknown constant!");
1607     }
1608     Stream.EmitRecord(Code, Record, AbbrevToUse);
1609     Record.clear();
1610   }
1611
1612   Stream.ExitBlock();
1613 }
1614
1615 static void WriteModuleConstants(const ValueEnumerator &VE,
1616                                  BitstreamWriter &Stream) {
1617   const ValueEnumerator::ValueList &Vals = VE.getValues();
1618
1619   // Find the first constant to emit, which is the first non-globalvalue value.
1620   // We know globalvalues have been emitted by WriteModuleInfo.
1621   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1622     if (!isa<GlobalValue>(Vals[i].first)) {
1623       WriteConstants(i, Vals.size(), VE, Stream, true);
1624       return;
1625     }
1626   }
1627 }
1628
1629 /// PushValueAndType - The file has to encode both the value and type id for
1630 /// many values, because we need to know what type to create for forward
1631 /// references.  However, most operands are not forward references, so this type
1632 /// field is not needed.
1633 ///
1634 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1635 /// instruction ID, then it is a forward reference, and it also includes the
1636 /// type ID.  The value ID that is written is encoded relative to the InstID.
1637 static bool PushValueAndType(const Value *V, unsigned InstID,
1638                              SmallVectorImpl<unsigned> &Vals,
1639                              ValueEnumerator &VE) {
1640   unsigned ValID = VE.getValueID(V);
1641   // Make encoding relative to the InstID.
1642   Vals.push_back(InstID - ValID);
1643   if (ValID >= InstID) {
1644     Vals.push_back(VE.getTypeID(V->getType()));
1645     return true;
1646   }
1647   return false;
1648 }
1649
1650 /// pushValue - Like PushValueAndType, but where the type of the value is
1651 /// omitted (perhaps it was already encoded in an earlier operand).
1652 static void pushValue(const Value *V, unsigned InstID,
1653                       SmallVectorImpl<unsigned> &Vals,
1654                       ValueEnumerator &VE) {
1655   unsigned ValID = VE.getValueID(V);
1656   Vals.push_back(InstID - ValID);
1657 }
1658
1659 static void pushValueSigned(const Value *V, unsigned InstID,
1660                             SmallVectorImpl<uint64_t> &Vals,
1661                             ValueEnumerator &VE) {
1662   unsigned ValID = VE.getValueID(V);
1663   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1664   emitSignedInt64(Vals, diff);
1665 }
1666
1667 /// WriteInstruction - Emit an instruction to the specified stream.
1668 static void WriteInstruction(const Instruction &I, unsigned InstID,
1669                              ValueEnumerator &VE, BitstreamWriter &Stream,
1670                              SmallVectorImpl<unsigned> &Vals) {
1671   unsigned Code = 0;
1672   unsigned AbbrevToUse = 0;
1673   VE.setInstructionID(&I);
1674   switch (I.getOpcode()) {
1675   default:
1676     if (Instruction::isCast(I.getOpcode())) {
1677       Code = bitc::FUNC_CODE_INST_CAST;
1678       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1679         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1680       Vals.push_back(VE.getTypeID(I.getType()));
1681       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1682     } else {
1683       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1684       Code = bitc::FUNC_CODE_INST_BINOP;
1685       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1686         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1687       pushValue(I.getOperand(1), InstID, Vals, VE);
1688       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1689       uint64_t Flags = GetOptimizationFlags(&I);
1690       if (Flags != 0) {
1691         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1692           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1693         Vals.push_back(Flags);
1694       }
1695     }
1696     break;
1697
1698   case Instruction::GetElementPtr: {
1699     Code = bitc::FUNC_CODE_INST_GEP;
1700     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1701     auto &GEPInst = cast<GetElementPtrInst>(I);
1702     Vals.push_back(GEPInst.isInBounds());
1703     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1704     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1705       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1706     break;
1707   }
1708   case Instruction::ExtractValue: {
1709     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1710     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1711     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1712     Vals.append(EVI->idx_begin(), EVI->idx_end());
1713     break;
1714   }
1715   case Instruction::InsertValue: {
1716     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1717     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1718     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1719     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1720     Vals.append(IVI->idx_begin(), IVI->idx_end());
1721     break;
1722   }
1723   case Instruction::Select:
1724     Code = bitc::FUNC_CODE_INST_VSELECT;
1725     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1726     pushValue(I.getOperand(2), InstID, Vals, VE);
1727     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1728     break;
1729   case Instruction::ExtractElement:
1730     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1731     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1732     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1733     break;
1734   case Instruction::InsertElement:
1735     Code = bitc::FUNC_CODE_INST_INSERTELT;
1736     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1737     pushValue(I.getOperand(1), InstID, Vals, VE);
1738     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1739     break;
1740   case Instruction::ShuffleVector:
1741     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1742     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1743     pushValue(I.getOperand(1), InstID, Vals, VE);
1744     pushValue(I.getOperand(2), InstID, Vals, VE);
1745     break;
1746   case Instruction::ICmp:
1747   case Instruction::FCmp:
1748     // compare returning Int1Ty or vector of Int1Ty
1749     Code = bitc::FUNC_CODE_INST_CMP2;
1750     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1751     pushValue(I.getOperand(1), InstID, Vals, VE);
1752     Vals.push_back(cast<CmpInst>(I).getPredicate());
1753     break;
1754
1755   case Instruction::Ret:
1756     {
1757       Code = bitc::FUNC_CODE_INST_RET;
1758       unsigned NumOperands = I.getNumOperands();
1759       if (NumOperands == 0)
1760         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1761       else if (NumOperands == 1) {
1762         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1763           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1764       } else {
1765         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1766           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1767       }
1768     }
1769     break;
1770   case Instruction::Br:
1771     {
1772       Code = bitc::FUNC_CODE_INST_BR;
1773       const BranchInst &II = cast<BranchInst>(I);
1774       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1775       if (II.isConditional()) {
1776         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1777         pushValue(II.getCondition(), InstID, Vals, VE);
1778       }
1779     }
1780     break;
1781   case Instruction::Switch:
1782     {
1783       Code = bitc::FUNC_CODE_INST_SWITCH;
1784       const SwitchInst &SI = cast<SwitchInst>(I);
1785       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1786       pushValue(SI.getCondition(), InstID, Vals, VE);
1787       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1788       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1789            i != e; ++i) {
1790         Vals.push_back(VE.getValueID(i.getCaseValue()));
1791         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1792       }
1793     }
1794     break;
1795   case Instruction::IndirectBr:
1796     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1797     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1798     // Encode the address operand as relative, but not the basic blocks.
1799     pushValue(I.getOperand(0), InstID, Vals, VE);
1800     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1801       Vals.push_back(VE.getValueID(I.getOperand(i)));
1802     break;
1803
1804   case Instruction::Invoke: {
1805     const InvokeInst *II = cast<InvokeInst>(&I);
1806     const Value *Callee = II->getCalledValue();
1807     FunctionType *FTy = II->getFunctionType();
1808     Code = bitc::FUNC_CODE_INST_INVOKE;
1809
1810     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1811     Vals.push_back(II->getCallingConv() | 1 << 13);
1812     Vals.push_back(VE.getValueID(II->getNormalDest()));
1813     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1814     Vals.push_back(VE.getTypeID(FTy));
1815     PushValueAndType(Callee, InstID, Vals, VE);
1816
1817     // Emit value #'s for the fixed parameters.
1818     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1819       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1820
1821     // Emit type/value pairs for varargs params.
1822     if (FTy->isVarArg()) {
1823       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1824            i != e; ++i)
1825         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1826     }
1827     break;
1828   }
1829   case Instruction::Resume:
1830     Code = bitc::FUNC_CODE_INST_RESUME;
1831     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1832     break;
1833   case Instruction::Unreachable:
1834     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1835     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1836     break;
1837
1838   case Instruction::PHI: {
1839     const PHINode &PN = cast<PHINode>(I);
1840     Code = bitc::FUNC_CODE_INST_PHI;
1841     // With the newer instruction encoding, forward references could give
1842     // negative valued IDs.  This is most common for PHIs, so we use
1843     // signed VBRs.
1844     SmallVector<uint64_t, 128> Vals64;
1845     Vals64.push_back(VE.getTypeID(PN.getType()));
1846     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1847       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1848       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1849     }
1850     // Emit a Vals64 vector and exit.
1851     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1852     Vals64.clear();
1853     return;
1854   }
1855
1856   case Instruction::LandingPad: {
1857     const LandingPadInst &LP = cast<LandingPadInst>(I);
1858     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1859     Vals.push_back(VE.getTypeID(LP.getType()));
1860     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1861     Vals.push_back(LP.isCleanup());
1862     Vals.push_back(LP.getNumClauses());
1863     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1864       if (LP.isCatch(I))
1865         Vals.push_back(LandingPadInst::Catch);
1866       else
1867         Vals.push_back(LandingPadInst::Filter);
1868       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1869     }
1870     break;
1871   }
1872
1873   case Instruction::Alloca: {
1874     Code = bitc::FUNC_CODE_INST_ALLOCA;
1875     const AllocaInst &AI = cast<AllocaInst>(I);
1876     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
1877     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1878     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1879     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1880     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1881            "not enough bits for maximum alignment");
1882     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1883     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1884     AlignRecord |= 1 << 6;
1885     Vals.push_back(AlignRecord);
1886     break;
1887   }
1888
1889   case Instruction::Load:
1890     if (cast<LoadInst>(I).isAtomic()) {
1891       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1892       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1893     } else {
1894       Code = bitc::FUNC_CODE_INST_LOAD;
1895       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1896         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1897     }
1898     Vals.push_back(VE.getTypeID(I.getType()));
1899     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1900     Vals.push_back(cast<LoadInst>(I).isVolatile());
1901     if (cast<LoadInst>(I).isAtomic()) {
1902       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1903       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1904     }
1905     break;
1906   case Instruction::Store:
1907     if (cast<StoreInst>(I).isAtomic())
1908       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1909     else
1910       Code = bitc::FUNC_CODE_INST_STORE;
1911     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1912     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
1913     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1914     Vals.push_back(cast<StoreInst>(I).isVolatile());
1915     if (cast<StoreInst>(I).isAtomic()) {
1916       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1917       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1918     }
1919     break;
1920   case Instruction::AtomicCmpXchg:
1921     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1922     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1923     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
1924     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1925     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1926     Vals.push_back(GetEncodedOrdering(
1927                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1928     Vals.push_back(GetEncodedSynchScope(
1929                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1930     Vals.push_back(GetEncodedOrdering(
1931                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1932     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1933     break;
1934   case Instruction::AtomicRMW:
1935     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1936     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1937     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1938     Vals.push_back(GetEncodedRMWOperation(
1939                      cast<AtomicRMWInst>(I).getOperation()));
1940     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1941     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1942     Vals.push_back(GetEncodedSynchScope(
1943                      cast<AtomicRMWInst>(I).getSynchScope()));
1944     break;
1945   case Instruction::Fence:
1946     Code = bitc::FUNC_CODE_INST_FENCE;
1947     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1948     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1949     break;
1950   case Instruction::Call: {
1951     const CallInst &CI = cast<CallInst>(I);
1952     FunctionType *FTy = CI.getFunctionType();
1953
1954     Code = bitc::FUNC_CODE_INST_CALL;
1955
1956     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1957     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1958                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
1959     Vals.push_back(VE.getTypeID(FTy));
1960     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1961
1962     // Emit value #'s for the fixed parameters.
1963     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1964       // Check for labels (can happen with asm labels).
1965       if (FTy->getParamType(i)->isLabelTy())
1966         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1967       else
1968         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1969     }
1970
1971     // Emit type/value pairs for varargs params.
1972     if (FTy->isVarArg()) {
1973       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1974            i != e; ++i)
1975         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1976     }
1977     break;
1978   }
1979   case Instruction::VAArg:
1980     Code = bitc::FUNC_CODE_INST_VAARG;
1981     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1982     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1983     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1984     break;
1985   }
1986
1987   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1988   Vals.clear();
1989 }
1990
1991 // Emit names for globals/functions etc.
1992 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1993                                   const ValueEnumerator &VE,
1994                                   BitstreamWriter &Stream) {
1995   if (VST.empty()) return;
1996   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1997
1998   // FIXME: Set up the abbrev, we know how many values there are!
1999   // FIXME: We know if the type names can use 7-bit ascii.
2000   SmallVector<unsigned, 64> NameVals;
2001
2002   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
2003        SI != SE; ++SI) {
2004
2005     const ValueName &Name = *SI;
2006
2007     // Figure out the encoding to use for the name.
2008     bool is7Bit = true;
2009     bool isChar6 = true;
2010     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
2011          C != E; ++C) {
2012       if (isChar6)
2013         isChar6 = BitCodeAbbrevOp::isChar6(*C);
2014       if ((unsigned char)*C & 128) {
2015         is7Bit = false;
2016         break;  // don't bother scanning the rest.
2017       }
2018     }
2019
2020     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2021
2022     // VST_ENTRY:   [valueid, namechar x N]
2023     // VST_BBENTRY: [bbid, namechar x N]
2024     unsigned Code;
2025     if (isa<BasicBlock>(SI->getValue())) {
2026       Code = bitc::VST_CODE_BBENTRY;
2027       if (isChar6)
2028         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2029     } else {
2030       Code = bitc::VST_CODE_ENTRY;
2031       if (isChar6)
2032         AbbrevToUse = VST_ENTRY_6_ABBREV;
2033       else if (is7Bit)
2034         AbbrevToUse = VST_ENTRY_7_ABBREV;
2035     }
2036
2037     NameVals.push_back(VE.getValueID(SI->getValue()));
2038     for (const char *P = Name.getKeyData(),
2039          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2040       NameVals.push_back((unsigned char)*P);
2041
2042     // Emit the finished record.
2043     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2044     NameVals.clear();
2045   }
2046   Stream.ExitBlock();
2047 }
2048
2049 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2050                          BitstreamWriter &Stream) {
2051   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2052   unsigned Code;
2053   if (isa<BasicBlock>(Order.V))
2054     Code = bitc::USELIST_CODE_BB;
2055   else
2056     Code = bitc::USELIST_CODE_DEFAULT;
2057
2058   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2059   Record.push_back(VE.getValueID(Order.V));
2060   Stream.EmitRecord(Code, Record);
2061 }
2062
2063 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2064                               BitstreamWriter &Stream) {
2065   assert(VE.shouldPreserveUseListOrder() &&
2066          "Expected to be preserving use-list order");
2067
2068   auto hasMore = [&]() {
2069     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2070   };
2071   if (!hasMore())
2072     // Nothing to do.
2073     return;
2074
2075   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2076   while (hasMore()) {
2077     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2078     VE.UseListOrders.pop_back();
2079   }
2080   Stream.ExitBlock();
2081 }
2082
2083 /// WriteFunction - Emit a function body to the module stream.
2084 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2085                           BitstreamWriter &Stream) {
2086   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2087   VE.incorporateFunction(F);
2088
2089   SmallVector<unsigned, 64> Vals;
2090
2091   // Emit the number of basic blocks, so the reader can create them ahead of
2092   // time.
2093   Vals.push_back(VE.getBasicBlocks().size());
2094   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2095   Vals.clear();
2096
2097   // If there are function-local constants, emit them now.
2098   unsigned CstStart, CstEnd;
2099   VE.getFunctionConstantRange(CstStart, CstEnd);
2100   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2101
2102   // If there is function-local metadata, emit it now.
2103   WriteFunctionLocalMetadata(F, VE, Stream);
2104
2105   // Keep a running idea of what the instruction ID is.
2106   unsigned InstID = CstEnd;
2107
2108   bool NeedsMetadataAttachment = F.hasMetadata();
2109
2110   DILocation *LastDL = nullptr;
2111
2112   // Finally, emit all the instructions, in order.
2113   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2114     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2115          I != E; ++I) {
2116       WriteInstruction(*I, InstID, VE, Stream, Vals);
2117
2118       if (!I->getType()->isVoidTy())
2119         ++InstID;
2120
2121       // If the instruction has metadata, write a metadata attachment later.
2122       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2123
2124       // If the instruction has a debug location, emit it.
2125       DILocation *DL = I->getDebugLoc();
2126       if (!DL)
2127         continue;
2128
2129       if (DL == LastDL) {
2130         // Just repeat the same debug loc as last time.
2131         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2132         continue;
2133       }
2134
2135       Vals.push_back(DL->getLine());
2136       Vals.push_back(DL->getColumn());
2137       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2138       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2139       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2140       Vals.clear();
2141
2142       LastDL = DL;
2143     }
2144
2145   // Emit names for all the instructions etc.
2146   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2147
2148   if (NeedsMetadataAttachment)
2149     WriteMetadataAttachment(F, VE, Stream);
2150   if (VE.shouldPreserveUseListOrder())
2151     WriteUseListBlock(&F, VE, Stream);
2152   VE.purgeFunction();
2153   Stream.ExitBlock();
2154 }
2155
2156 // Emit blockinfo, which defines the standard abbreviations etc.
2157 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2158   // We only want to emit block info records for blocks that have multiple
2159   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2160   // Other blocks can define their abbrevs inline.
2161   Stream.EnterBlockInfoBlock(2);
2162
2163   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2164     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2169     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2170                                    Abbv) != VST_ENTRY_8_ABBREV)
2171       llvm_unreachable("Unexpected abbrev ordering!");
2172   }
2173
2174   { // 7-bit fixed width VST_ENTRY strings.
2175     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2176     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2179     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2180     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2181                                    Abbv) != VST_ENTRY_7_ABBREV)
2182       llvm_unreachable("Unexpected abbrev ordering!");
2183   }
2184   { // 6-bit char6 VST_ENTRY strings.
2185     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2186     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2190     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2191                                    Abbv) != VST_ENTRY_6_ABBREV)
2192       llvm_unreachable("Unexpected abbrev ordering!");
2193   }
2194   { // 6-bit char6 VST_BBENTRY strings.
2195     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2196     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2200     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2201                                    Abbv) != VST_BBENTRY_6_ABBREV)
2202       llvm_unreachable("Unexpected abbrev ordering!");
2203   }
2204
2205
2206
2207   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2208     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2209     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2211                               VE.computeBitsRequiredForTypeIndicies()));
2212     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2213                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2214       llvm_unreachable("Unexpected abbrev ordering!");
2215   }
2216
2217   { // INTEGER abbrev for CONSTANTS_BLOCK.
2218     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2219     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2221     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2222                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2223       llvm_unreachable("Unexpected abbrev ordering!");
2224   }
2225
2226   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2227     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2228     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2229     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2230     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2231                               VE.computeBitsRequiredForTypeIndicies()));
2232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2233
2234     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2235                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2236       llvm_unreachable("Unexpected abbrev ordering!");
2237   }
2238   { // NULL abbrev for CONSTANTS_BLOCK.
2239     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2240     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2241     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2242                                    Abbv) != CONSTANTS_NULL_Abbrev)
2243       llvm_unreachable("Unexpected abbrev ordering!");
2244   }
2245
2246   // FIXME: This should only use space for first class types!
2247
2248   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2249     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2250     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2253                               VE.computeBitsRequiredForTypeIndicies()));
2254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2256     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2257                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2258       llvm_unreachable("Unexpected abbrev ordering!");
2259   }
2260   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2261     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2262     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2263     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2266     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2267                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2268       llvm_unreachable("Unexpected abbrev ordering!");
2269   }
2270   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2271     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2272     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2273     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2274     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2275     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2277     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2278                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2279       llvm_unreachable("Unexpected abbrev ordering!");
2280   }
2281   { // INST_CAST abbrev for FUNCTION_BLOCK.
2282     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2283     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2286                               VE.computeBitsRequiredForTypeIndicies()));
2287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2288     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2289                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2290       llvm_unreachable("Unexpected abbrev ordering!");
2291   }
2292
2293   { // INST_RET abbrev for FUNCTION_BLOCK.
2294     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2295     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2296     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2297                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2298       llvm_unreachable("Unexpected abbrev ordering!");
2299   }
2300   { // INST_RET abbrev for FUNCTION_BLOCK.
2301     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2302     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2304     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2305                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2306       llvm_unreachable("Unexpected abbrev ordering!");
2307   }
2308   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2309     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2310     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2311     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2312                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2313       llvm_unreachable("Unexpected abbrev ordering!");
2314   }
2315   {
2316     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2317     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2319     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2320                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2323     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2324         FUNCTION_INST_GEP_ABBREV)
2325       llvm_unreachable("Unexpected abbrev ordering!");
2326   }
2327
2328   Stream.ExitBlock();
2329 }
2330
2331 /// WriteModule - Emit the specified module to the bitstream.
2332 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2333                         bool ShouldPreserveUseListOrder) {
2334   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2335
2336   SmallVector<unsigned, 1> Vals;
2337   unsigned CurVersion = 1;
2338   Vals.push_back(CurVersion);
2339   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2340
2341   // Analyze the module, enumerating globals, functions, etc.
2342   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2343
2344   // Emit blockinfo, which defines the standard abbreviations etc.
2345   WriteBlockInfo(VE, Stream);
2346
2347   // Emit information about attribute groups.
2348   WriteAttributeGroupTable(VE, Stream);
2349
2350   // Emit information about parameter attributes.
2351   WriteAttributeTable(VE, Stream);
2352
2353   // Emit information describing all of the types in the module.
2354   WriteTypeTable(VE, Stream);
2355
2356   writeComdats(VE, Stream);
2357
2358   // Emit top-level description of module, including target triple, inline asm,
2359   // descriptors for global variables, and function prototype info.
2360   WriteModuleInfo(M, VE, Stream);
2361
2362   // Emit constants.
2363   WriteModuleConstants(VE, Stream);
2364
2365   // Emit metadata.
2366   WriteModuleMetadata(M, VE, Stream);
2367
2368   // Emit metadata.
2369   WriteModuleMetadataStore(M, Stream);
2370
2371   // Emit names for globals/functions etc.
2372   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2373
2374   // Emit module-level use-lists.
2375   if (VE.shouldPreserveUseListOrder())
2376     WriteUseListBlock(nullptr, VE, Stream);
2377
2378   // Emit function bodies.
2379   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2380     if (!F->isDeclaration())
2381       WriteFunction(*F, VE, Stream);
2382
2383   Stream.ExitBlock();
2384 }
2385
2386 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2387 /// header and trailer to make it compatible with the system archiver.  To do
2388 /// this we emit the following header, and then emit a trailer that pads the
2389 /// file out to be a multiple of 16 bytes.
2390 ///
2391 /// struct bc_header {
2392 ///   uint32_t Magic;         // 0x0B17C0DE
2393 ///   uint32_t Version;       // Version, currently always 0.
2394 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2395 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2396 ///   uint32_t CPUType;       // CPU specifier.
2397 ///   ... potentially more later ...
2398 /// };
2399 enum {
2400   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2401   DarwinBCHeaderSize = 5*4
2402 };
2403
2404 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2405                                uint32_t &Position) {
2406   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2407   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2408   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2409   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2410   Position += 4;
2411 }
2412
2413 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2414                                          const Triple &TT) {
2415   unsigned CPUType = ~0U;
2416
2417   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2418   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2419   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2420   // specific constants here because they are implicitly part of the Darwin ABI.
2421   enum {
2422     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2423     DARWIN_CPU_TYPE_X86        = 7,
2424     DARWIN_CPU_TYPE_ARM        = 12,
2425     DARWIN_CPU_TYPE_POWERPC    = 18
2426   };
2427
2428   Triple::ArchType Arch = TT.getArch();
2429   if (Arch == Triple::x86_64)
2430     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2431   else if (Arch == Triple::x86)
2432     CPUType = DARWIN_CPU_TYPE_X86;
2433   else if (Arch == Triple::ppc)
2434     CPUType = DARWIN_CPU_TYPE_POWERPC;
2435   else if (Arch == Triple::ppc64)
2436     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2437   else if (Arch == Triple::arm || Arch == Triple::thumb)
2438     CPUType = DARWIN_CPU_TYPE_ARM;
2439
2440   // Traditional Bitcode starts after header.
2441   assert(Buffer.size() >= DarwinBCHeaderSize &&
2442          "Expected header size to be reserved");
2443   unsigned BCOffset = DarwinBCHeaderSize;
2444   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2445
2446   // Write the magic and version.
2447   unsigned Position = 0;
2448   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2449   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2450   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2451   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2452   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2453
2454   // If the file is not a multiple of 16 bytes, insert dummy padding.
2455   while (Buffer.size() & 15)
2456     Buffer.push_back(0);
2457 }
2458
2459 /// WriteBitcodeToFile - Write the specified module to the specified output
2460 /// stream.
2461 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2462                               bool ShouldPreserveUseListOrder) {
2463   SmallVector<char, 0> Buffer;
2464   Buffer.reserve(256*1024);
2465
2466   // If this is darwin or another generic macho target, reserve space for the
2467   // header.
2468   Triple TT(M->getTargetTriple());
2469   if (TT.isOSDarwin())
2470     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2471
2472   // Emit the module into the buffer.
2473   {
2474     BitstreamWriter Stream(Buffer);
2475
2476     // Emit the file header.
2477     Stream.Emit((unsigned)'B', 8);
2478     Stream.Emit((unsigned)'C', 8);
2479     Stream.Emit(0x0, 4);
2480     Stream.Emit(0xC, 4);
2481     Stream.Emit(0xE, 4);
2482     Stream.Emit(0xD, 4);
2483
2484     // Emit the module.
2485     WriteModule(M, Stream, ShouldPreserveUseListOrder);
2486   }
2487
2488   if (TT.isOSDarwin())
2489     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2490
2491   // Write the generated bitstream to "Out".
2492   Out.write((char*)&Buffer.front(), Buffer.size());
2493 }