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::InAlloca:
 170     return bitc::ATTR_KIND_IN_ALLOCA;
 171   case Attribute::Cold:
 172     return bitc::ATTR_KIND_COLD;
 173   case Attribute::InlineHint:
 174     return bitc::ATTR_KIND_INLINE_HINT;
 175   case Attribute::InReg:
 176     return bitc::ATTR_KIND_IN_REG;
 177   case Attribute::JumpTable:
 178     return bitc::ATTR_KIND_JUMP_TABLE;
 179   case Attribute::MinSize:
 180     return bitc::ATTR_KIND_MIN_SIZE;
 181   case Attribute::Naked:
 182     return bitc::ATTR_KIND_NAKED;
 183   case Attribute::Nest:
 184     return bitc::ATTR_KIND_NEST;
 185   case Attribute::NoAlias:
 186     return bitc::ATTR_KIND_NO_ALIAS;
 187   case Attribute::NoBuiltin:
 188     return bitc::ATTR_KIND_NO_BUILTIN;
 189   case Attribute::NoCapture:
 190     return bitc::ATTR_KIND_NO_CAPTURE;
 191   case Attribute::NoDuplicate:
 192     return bitc::ATTR_KIND_NO_DUPLICATE;
 193   case Attribute::NoImplicitFloat:
 194     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 195   case Attribute::NoInline:
 196     return bitc::ATTR_KIND_NO_INLINE;
 197   case Attribute::NonLazyBind:
 198     return bitc::ATTR_KIND_NON_LAZY_BIND;
 199   case Attribute::NonNull:
 200     return bitc::ATTR_KIND_NON_NULL;
 201   case Attribute::Dereferenceable:
 202     return bitc::ATTR_KIND_DEREFERENCEABLE;
 203   case Attribute::DereferenceableOrNull:
 204     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
 205   case Attribute::NoRedZone:
 206     return bitc::ATTR_KIND_NO_RED_ZONE;
 207   case Attribute::NoReturn:
 208     return bitc::ATTR_KIND_NO_RETURN;
 209   case Attribute::NoUnwind:
 210     return bitc::ATTR_KIND_NO_UNWIND;
 211   case Attribute::OptimizeForSize:
 212     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 213   case Attribute::OptimizeNone:
 214     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 215   case Attribute::ReadNone:
 216     return bitc::ATTR_KIND_READ_NONE;
 217   case Attribute::ReadOnly:
 218     return bitc::ATTR_KIND_READ_ONLY;
 219   case Attribute::Returned:
 220     return bitc::ATTR_KIND_RETURNED;
 221   case Attribute::ReturnsTwice:
 222     return bitc::ATTR_KIND_RETURNS_TWICE;
 223   case Attribute::SExt:
 224     return bitc::ATTR_KIND_S_EXT;
 225   case Attribute::StackAlignment:
 226     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 227   case Attribute::StackProtect:
 228     return bitc::ATTR_KIND_STACK_PROTECT;
 229   case Attribute::StackProtectReq:
 230     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 231   case Attribute::StackProtectStrong:
 232     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 233   case Attribute::StructRet:
 234     return bitc::ATTR_KIND_STRUCT_RET;
 235   case Attribute::SanitizeAddress:
 236     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 237   case Attribute::SanitizeThread:
 238     return bitc::ATTR_KIND_SANITIZE_THREAD;
 239   case Attribute::SanitizeMemory:
 240     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 241   case Attribute::UWTable:
 242     return bitc::ATTR_KIND_UW_TABLE;
 243   case Attribute::ZExt:
 244     return bitc::ATTR_KIND_Z_EXT;
 245   case Attribute::EndAttrKinds:
 246     llvm_unreachable("Can not encode end-attribute kinds marker.");
 247   case Attribute::None:
 248     llvm_unreachable("Can not encode none-attribute.");
 249   }
 250
 251   llvm_unreachable("Trying to encode unknown attribute");
 252 }
 253
 254 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 255                                      BitstreamWriter &Stream) {
 256   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 257   if (AttrGrps.empty()) return;
 258
 259   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 260
 261   SmallVector<uint64_t, 64> Record;
 262   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 263     AttributeSet AS = AttrGrps[i];
 264     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 265       AttributeSet A = AS.getSlotAttributes(i);
 266
 267       Record.push_back(VE.getAttributeGroupID(A));
 268       Record.push_back(AS.getSlotIndex(i));
 269
 270       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 271            I != E; ++I) {
 272         Attribute Attr = *I;
 273         if (Attr.isEnumAttribute()) {
 274           Record.push_back(0);
 275           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 276         } else if (Attr.isIntAttribute()) {
 277           Record.push_back(1);
 278           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 279           Record.push_back(Attr.getValueAsInt());
 280         } else {
 281           StringRef Kind = Attr.getKindAsString();
 282           StringRef Val = Attr.getValueAsString();
 283
 284           Record.push_back(Val.empty() ? 3 : 4);
 285           Record.append(Kind.begin(), Kind.end());
 286           Record.push_back(0);
 287           if (!Val.empty()) {
 288             Record.append(Val.begin(), Val.end());
 289             Record.push_back(0);
 290           }
 291         }
 292       }
 293
 294       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 295       Record.clear();
 296     }
 297   }
 298
 299   Stream.ExitBlock();
 300 }
 301
 302 static void WriteAttributeTable(const ValueEnumerator &VE,
 303                                 BitstreamWriter &Stream) {
 304   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 305   if (Attrs.empty()) return;
 306
 307   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 308
 309   SmallVector<uint64_t, 64> Record;
 310   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 311     const AttributeSet &A = Attrs[i];
 312     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 313       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 314
 315     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 316     Record.clear();
 317   }
 318
 319   Stream.ExitBlock();
 320 }
 321
 322 /// WriteTypeTable - Write out the type table for a module.
 323 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 324   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 325
 326   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 327   SmallVector<uint64_t, 64> TypeVals;
 328
 329   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
 330
 331   // Abbrev for TYPE_CODE_POINTER.
 332   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 333   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 335   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 336   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 337
 338   // Abbrev for TYPE_CODE_FUNCTION.
 339   Abbv = new BitCodeAbbrev();
 340   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 344
 345   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 346
 347   // Abbrev for TYPE_CODE_STRUCT_ANON.
 348   Abbv = new BitCodeAbbrev();
 349   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 353
 354   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 355
 356   // Abbrev for TYPE_CODE_STRUCT_NAME.
 357   Abbv = new BitCodeAbbrev();
 358   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 361   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 362
 363   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 364   Abbv = new BitCodeAbbrev();
 365   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 369
 370   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 371
 372   // Abbrev for TYPE_CODE_ARRAY.
 373   Abbv = new BitCodeAbbrev();
 374   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 375   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 376   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 377
 378   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 379
 380   // Emit an entry count so the reader can reserve space.
 381   TypeVals.push_back(TypeList.size());
 382   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 383   TypeVals.clear();
 384
 385   // Loop over all of the types, emitting each in turn.
 386   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 387     Type *T = TypeList[i];
 388     int AbbrevToUse = 0;
 389     unsigned Code = 0;
 390
 391     switch (T->getTypeID()) {
 392     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 393     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 394     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 395     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 396     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 397     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 398     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 399     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 400     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 401     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 402     case Type::IntegerTyID:
 403       // INTEGER: [width]
 404       Code = bitc::TYPE_CODE_INTEGER;
 405       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 406       break;
 407     case Type::PointerTyID: {
 408       PointerType *PTy = cast<PointerType>(T);
 409       // POINTER: [pointee type, address space]
 410       Code = bitc::TYPE_CODE_POINTER;
 411       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 412       unsigned AddressSpace = PTy->getAddressSpace();
 413       TypeVals.push_back(AddressSpace);
 414       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 415       break;
 416     }
 417     case Type::FunctionTyID: {
 418       FunctionType *FT = cast<FunctionType>(T);
 419       // FUNCTION: [isvararg, retty, paramty x N]
 420       Code = bitc::TYPE_CODE_FUNCTION;
 421       TypeVals.push_back(FT->isVarArg());
 422       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 423       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 424         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 425       AbbrevToUse = FunctionAbbrev;
 426       break;
 427     }
 428     case Type::StructTyID: {
 429       StructType *ST = cast<StructType>(T);
 430       // STRUCT: [ispacked, eltty x N]
 431       TypeVals.push_back(ST->isPacked());
 432       // Output all of the element types.
 433       for (StructType::element_iterator I = ST->element_begin(),
 434            E = ST->element_end(); I != E; ++I)
 435         TypeVals.push_back(VE.getTypeID(*I));
 436
 437       if (ST->isLiteral()) {
 438         Code = bitc::TYPE_CODE_STRUCT_ANON;
 439         AbbrevToUse = StructAnonAbbrev;
 440       } else {
 441         if (ST->isOpaque()) {
 442           Code = bitc::TYPE_CODE_OPAQUE;
 443         } else {
 444           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 445           AbbrevToUse = StructNamedAbbrev;
 446         }
 447
 448         // Emit the name if it is present.
 449         if (!ST->getName().empty())
 450           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 451                             StructNameAbbrev, Stream);
 452       }
 453       break;
 454     }
 455     case Type::ArrayTyID: {
 456       ArrayType *AT = cast<ArrayType>(T);
 457       // ARRAY: [numelts, eltty]
 458       Code = bitc::TYPE_CODE_ARRAY;
 459       TypeVals.push_back(AT->getNumElements());
 460       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 461       AbbrevToUse = ArrayAbbrev;
 462       break;
 463     }
 464     case Type::VectorTyID: {
 465       VectorType *VT = cast<VectorType>(T);
 466       // VECTOR [numelts, eltty]
 467       Code = bitc::TYPE_CODE_VECTOR;
 468       TypeVals.push_back(VT->getNumElements());
 469       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 470       break;
 471     }
 472     }
 473
 474     // Emit the finished record.
 475     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 476     TypeVals.clear();
 477   }
 478
 479   Stream.ExitBlock();
 480 }
 481
 482 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 483   switch (GV.getLinkage()) {
 484   case GlobalValue::ExternalLinkage:
 485     return 0;
 486   case GlobalValue::WeakAnyLinkage:
 487     return 16;
 488   case GlobalValue::AppendingLinkage:
 489     return 2;
 490   case GlobalValue::InternalLinkage:
 491     return 3;
 492   case GlobalValue::LinkOnceAnyLinkage:
 493     return 18;
 494   case GlobalValue::ExternalWeakLinkage:
 495     return 7;
 496   case GlobalValue::CommonLinkage:
 497     return 8;
 498   case GlobalValue::PrivateLinkage:
 499     return 9;
 500   case GlobalValue::WeakODRLinkage:
 501     return 17;
 502   case GlobalValue::LinkOnceODRLinkage:
 503     return 19;
 504   case GlobalValue::AvailableExternallyLinkage:
 505     return 12;
 506   }
 507   llvm_unreachable("Invalid linkage");
 508 }
 509
 510 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 511   switch (GV.getVisibility()) {
 512   case GlobalValue::DefaultVisibility:   return 0;
 513   case GlobalValue::HiddenVisibility:    return 1;
 514   case GlobalValue::ProtectedVisibility: return 2;
 515   }
 516   llvm_unreachable("Invalid visibility");
 517 }
 518
 519 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 520   switch (GV.getDLLStorageClass()) {
 521   case GlobalValue::DefaultStorageClass:   return 0;
 522   case GlobalValue::DLLImportStorageClass: return 1;
 523   case GlobalValue::DLLExportStorageClass: return 2;
 524   }
 525   llvm_unreachable("Invalid DLL storage class");
 526 }
 527
 528 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 529   switch (GV.getThreadLocalMode()) {
 530     case GlobalVariable::NotThreadLocal:         return 0;
 531     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 532     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 533     case GlobalVariable::InitialExecTLSModel:    return 3;
 534     case GlobalVariable::LocalExecTLSModel:      return 4;
 535   }
 536   llvm_unreachable("Invalid TLS model");
 537 }
 538
 539 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 540   switch (C.getSelectionKind()) {
 541   case Comdat::Any:
 542     return bitc::COMDAT_SELECTION_KIND_ANY;
 543   case Comdat::ExactMatch:
 544     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 545   case Comdat::Largest:
 546     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 547   case Comdat::NoDuplicates:
 548     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 549   case Comdat::SameSize:
 550     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 551   }
 552   llvm_unreachable("Invalid selection kind");
 553 }
 554
 555 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 556   SmallVector<uint16_t, 64> Vals;
 557   for (const Comdat *C : VE.getComdats()) {
 558     // COMDAT: [selection_kind, name]
 559     Vals.push_back(getEncodedComdatSelectionKind(*C));
 560     size_t Size = C->getName().size();
 561     assert(isUInt<16>(Size));
 562     Vals.push_back(Size);
 563     for (char Chr : C->getName())
 564       Vals.push_back((unsigned char)Chr);
 565     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 566     Vals.clear();
 567   }
 568 }
 569
 570 // Emit top-level description of module, including target triple, inline asm,
 571 // descriptors for global variables, and function prototype info.
 572 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 573                             BitstreamWriter &Stream) {
 574   // Emit various pieces of data attached to a module.
 575   if (!M->getTargetTriple().empty())
 576     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 577                       0/*TODO*/, Stream);
 578   const std::string &DL = M->getDataLayoutStr();
 579   if (!DL.empty())
 580     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 581   if (!M->getModuleInlineAsm().empty())
 582     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 583                       0/*TODO*/, Stream);
 584
 585   // Emit information about sections and GC, computing how many there are. Also
 586   // compute the maximum alignment value.
 587   std::map<std::string, unsigned> SectionMap;
 588   std::map<std::string, unsigned> GCMap;
 589   unsigned MaxAlignment = 0;
 590   unsigned MaxGlobalType = 0;
 591   for (const GlobalValue &GV : M->globals()) {
 592     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 593     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 594     if (GV.hasSection()) {
 595       // Give section names unique ID's.
 596       unsigned &Entry = SectionMap[GV.getSection()];
 597       if (!Entry) {
 598         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 599                           0/*TODO*/, Stream);
 600         Entry = SectionMap.size();
 601       }
 602     }
 603   }
 604   for (const Function &F : *M) {
 605     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 606     if (F.hasSection()) {
 607       // Give section names unique ID's.
 608       unsigned &Entry = SectionMap[F.getSection()];
 609       if (!Entry) {
 610         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 611                           0/*TODO*/, Stream);
 612         Entry = SectionMap.size();
 613       }
 614     }
 615     if (F.hasGC()) {
 616       // Same for GC names.
 617       unsigned &Entry = GCMap[F.getGC()];
 618       if (!Entry) {
 619         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 620                           0/*TODO*/, Stream);
 621         Entry = GCMap.size();
 622       }
 623     }
 624   }
 625
 626   // Emit abbrev for globals, now that we know # sections and max alignment.
 627   unsigned SimpleGVarAbbrev = 0;
 628   if (!M->global_empty()) {
 629     // Add an abbrev for common globals with no visibility or thread localness.
 630     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 631     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 633                               Log2_32_Ceil(MaxGlobalType+1)));
 634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5));      // Linkage.
 637     if (MaxAlignment == 0)                                      // Alignment.
 638       Abbv->Add(BitCodeAbbrevOp(0));
 639     else {
 640       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 641       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 642                                Log2_32_Ceil(MaxEncAlignment+1)));
 643     }
 644     if (SectionMap.empty())                                    // Section.
 645       Abbv->Add(BitCodeAbbrevOp(0));
 646     else
 647       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 648                                Log2_32_Ceil(SectionMap.size()+1)));
 649     // Don't bother emitting vis + thread local.
 650     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 651   }
 652
 653   // Emit the global variable information.
 654   SmallVector<unsigned, 64> Vals;
 655   for (const GlobalVariable &GV : M->globals()) {
 656     unsigned AbbrevToUse = 0;
 657
 658     // GLOBALVAR: [type, isconst, initid,
 659     //             linkage, alignment, section, visibility, threadlocal,
 660     //             unnamed_addr, externally_initialized, dllstorageclass,
 661     //             comdat]
 662     Vals.push_back(VE.getTypeID(GV.getType()));
 663     Vals.push_back(GV.isConstant());
 664     Vals.push_back(GV.isDeclaration() ? 0 :
 665                    (VE.getValueID(GV.getInitializer()) + 1));
 666     Vals.push_back(getEncodedLinkage(GV));
 667     Vals.push_back(Log2_32(GV.getAlignment())+1);
 668     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 669     if (GV.isThreadLocal() ||
 670         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 671         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 672         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 673         GV.hasComdat()) {
 674       Vals.push_back(getEncodedVisibility(GV));
 675       Vals.push_back(getEncodedThreadLocalMode(GV));
 676       Vals.push_back(GV.hasUnnamedAddr());
 677       Vals.push_back(GV.isExternallyInitialized());
 678       Vals.push_back(getEncodedDLLStorageClass(GV));
 679       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 680     } else {
 681       AbbrevToUse = SimpleGVarAbbrev;
 682     }
 683
 684     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 685     Vals.clear();
 686   }
 687
 688   // Emit the function proto information.
 689   for (const Function &F : *M) {
 690     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 691     //             section, visibility, gc, unnamed_addr, prologuedata,
 692     //             dllstorageclass, comdat, prefixdata]
 693     Vals.push_back(VE.getTypeID(F.getType()));
 694     Vals.push_back(F.getCallingConv());
 695     Vals.push_back(F.isDeclaration());
 696     Vals.push_back(getEncodedLinkage(F));
 697     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 698     Vals.push_back(Log2_32(F.getAlignment())+1);
 699     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 700     Vals.push_back(getEncodedVisibility(F));
 701     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 702     Vals.push_back(F.hasUnnamedAddr());
 703     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 704                                        : 0);
 705     Vals.push_back(getEncodedDLLStorageClass(F));
 706     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 707     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 708                                      : 0);
 709
 710     unsigned AbbrevToUse = 0;
 711     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 712     Vals.clear();
 713   }
 714
 715   // Emit the alias information.
 716   for (const GlobalAlias &A : M->aliases()) {
 717     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 718     Vals.push_back(VE.getTypeID(A.getType()));
 719     Vals.push_back(VE.getValueID(A.getAliasee()));
 720     Vals.push_back(getEncodedLinkage(A));
 721     Vals.push_back(getEncodedVisibility(A));
 722     Vals.push_back(getEncodedDLLStorageClass(A));
 723     Vals.push_back(getEncodedThreadLocalMode(A));
 724     Vals.push_back(A.hasUnnamedAddr());
 725     unsigned AbbrevToUse = 0;
 726     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 727     Vals.clear();
 728   }
 729 }
 730
 731 static uint64_t GetOptimizationFlags(const Value *V) {
 732   uint64_t Flags = 0;
 733
 734   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 735     if (OBO->hasNoSignedWrap())
 736       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 737     if (OBO->hasNoUnsignedWrap())
 738       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 739   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 740     if (PEO->isExact())
 741       Flags |= 1 << bitc::PEO_EXACT;
 742   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 743     if (FPMO->hasUnsafeAlgebra())
 744       Flags |= FastMathFlags::UnsafeAlgebra;
 745     if (FPMO->hasNoNaNs())
 746       Flags |= FastMathFlags::NoNaNs;
 747     if (FPMO->hasNoInfs())
 748       Flags |= FastMathFlags::NoInfs;
 749     if (FPMO->hasNoSignedZeros())
 750       Flags |= FastMathFlags::NoSignedZeros;
 751     if (FPMO->hasAllowReciprocal())
 752       Flags |= FastMathFlags::AllowReciprocal;
 753   }
 754
 755   return Flags;
 756 }
 757
 758 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 759                                  const ValueEnumerator &VE,
 760                                  BitstreamWriter &Stream,
 761                                  SmallVectorImpl<uint64_t> &Record) {
 762   // Mimic an MDNode with a value as one operand.
 763   Value *V = MD->getValue();
 764   Record.push_back(VE.getTypeID(V->getType()));
 765   Record.push_back(VE.getValueID(V));
 766   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 767   Record.clear();
 768 }
 769
 770 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 771                          BitstreamWriter &Stream,
 772                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 773   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 774     Metadata *MD = N->getOperand(i);
 775     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 776            "Unexpected function-local metadata");
 777     Record.push_back(VE.getMetadataOrNullID(MD));
 778   }
 779   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 780                                     : bitc::METADATA_NODE,
 781                     Record, Abbrev);
 782   Record.clear();
 783 }
 784
 785 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 786                             BitstreamWriter &Stream,
 787                             SmallVectorImpl<uint64_t> &Record,
 788                             unsigned Abbrev) {
 789   Record.push_back(N->isDistinct());
 790   Record.push_back(N->getLine());
 791   Record.push_back(N->getColumn());
 792   Record.push_back(VE.getMetadataID(N->getScope()));
 793   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 794
 795   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 796   Record.clear();
 797 }
 798
 799 static void WriteGenericDebugNode(const GenericDebugNode *N,
 800                                   const ValueEnumerator &VE,
 801                                   BitstreamWriter &Stream,
 802                                   SmallVectorImpl<uint64_t> &Record,
 803                                   unsigned Abbrev) {
 804   Record.push_back(N->isDistinct());
 805   Record.push_back(N->getTag());
 806   Record.push_back(0); // Per-tag version field; unused for now.
 807
 808   for (auto &I : N->operands())
 809     Record.push_back(VE.getMetadataOrNullID(I));
 810
 811   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 812   Record.clear();
 813 }
 814
 815 static uint64_t rotateSign(int64_t I) {
 816   uint64_t U = I;
 817   return I < 0 ? ~(U << 1) : U << 1;
 818 }
 819
 820 static void WriteMDSubrange(const MDSubrange *N, const ValueEnumerator &,
 821                             BitstreamWriter &Stream,
 822                             SmallVectorImpl<uint64_t> &Record,
 823                             unsigned Abbrev) {
 824   Record.push_back(N->isDistinct());
 825   Record.push_back(N->getCount());
 826   Record.push_back(rotateSign(N->getLowerBound()));
 827
 828   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 829   Record.clear();
 830 }
 831
 832 static void WriteMDEnumerator(const MDEnumerator *N, const ValueEnumerator &VE,
 833                               BitstreamWriter &Stream,
 834                               SmallVectorImpl<uint64_t> &Record,
 835                               unsigned Abbrev) {
 836   Record.push_back(N->isDistinct());
 837   Record.push_back(rotateSign(N->getValue()));
 838   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 839
 840   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 841   Record.clear();
 842 }
 843
 844 static void WriteMDBasicType(const MDBasicType *N, const ValueEnumerator &VE,
 845                              BitstreamWriter &Stream,
 846                              SmallVectorImpl<uint64_t> &Record,
 847                              unsigned Abbrev) {
 848   Record.push_back(N->isDistinct());
 849   Record.push_back(N->getTag());
 850   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 851   Record.push_back(N->getSizeInBits());
 852   Record.push_back(N->getAlignInBits());
 853   Record.push_back(N->getEncoding());
 854
 855   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 856   Record.clear();
 857 }
 858
 859 static void WriteMDDerivedType(const MDDerivedType *N,
 860                                const ValueEnumerator &VE,
 861                                BitstreamWriter &Stream,
 862                                SmallVectorImpl<uint64_t> &Record,
 863                                unsigned Abbrev) {
 864   Record.push_back(N->isDistinct());
 865   Record.push_back(N->getTag());
 866   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 867   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 868   Record.push_back(N->getLine());
 869   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 870   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 871   Record.push_back(N->getSizeInBits());
 872   Record.push_back(N->getAlignInBits());
 873   Record.push_back(N->getOffsetInBits());
 874   Record.push_back(N->getFlags());
 875   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 876
 877   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 878   Record.clear();
 879 }
 880
 881 static void WriteMDCompositeType(const MDCompositeType *N,
 882                                  const ValueEnumerator &VE,
 883                                  BitstreamWriter &Stream,
 884                                  SmallVectorImpl<uint64_t> &Record,
 885                                  unsigned Abbrev) {
 886   Record.push_back(N->isDistinct());
 887   Record.push_back(N->getTag());
 888   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 889   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 890   Record.push_back(N->getLine());
 891   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 892   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 893   Record.push_back(N->getSizeInBits());
 894   Record.push_back(N->getAlignInBits());
 895   Record.push_back(N->getOffsetInBits());
 896   Record.push_back(N->getFlags());
 897   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 898   Record.push_back(N->getRuntimeLang());
 899   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 900   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 901   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 902
 903   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 904   Record.clear();
 905 }
 906
 907 static void WriteMDSubroutineType(const MDSubroutineType *N,
 908                                   const ValueEnumerator &VE,
 909                                   BitstreamWriter &Stream,
 910                                   SmallVectorImpl<uint64_t> &Record,
 911                                   unsigned Abbrev) {
 912   Record.push_back(N->isDistinct());
 913   Record.push_back(N->getFlags());
 914   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 915
 916   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 917   Record.clear();
 918 }
 919
 920 static void WriteMDFile(const MDFile *N, const ValueEnumerator &VE,
 921                         BitstreamWriter &Stream,
 922                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 923   Record.push_back(N->isDistinct());
 924   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 925   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 926
 927   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 928   Record.clear();
 929 }
 930
 931 static void WriteMDCompileUnit(const MDCompileUnit *N,
 932                                const ValueEnumerator &VE,
 933                                BitstreamWriter &Stream,
 934                                SmallVectorImpl<uint64_t> &Record,
 935                                unsigned Abbrev) {
 936   Record.push_back(N->isDistinct());
 937   Record.push_back(N->getSourceLanguage());
 938   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 939   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 940   Record.push_back(N->isOptimized());
 941   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 942   Record.push_back(N->getRuntimeVersion());
 943   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 944   Record.push_back(N->getEmissionKind());
 945   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 946   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 947   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 948   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
 949   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
 950
 951   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 952   Record.clear();
 953 }
 954
 955 static void WriteMDSubprogram(const MDSubprogram *N,
 956                                const ValueEnumerator &VE,
 957                                BitstreamWriter &Stream,
 958                                SmallVectorImpl<uint64_t> &Record,
 959                                unsigned Abbrev) {
 960   Record.push_back(N->isDistinct());
 961   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 962   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 963   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 964   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 965   Record.push_back(N->getLine());
 966   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 967   Record.push_back(N->isLocalToUnit());
 968   Record.push_back(N->isDefinition());
 969   Record.push_back(N->getScopeLine());
 970   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 971   Record.push_back(N->getVirtuality());
 972   Record.push_back(N->getVirtualIndex());
 973   Record.push_back(N->getFlags());
 974   Record.push_back(N->isOptimized());
 975   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
 976   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 977   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 978   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
 979
 980   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 981   Record.clear();
 982 }
 983
 984 static void WriteMDLexicalBlock(const MDLexicalBlock *N,
 985                                const ValueEnumerator &VE,
 986                                BitstreamWriter &Stream,
 987                                SmallVectorImpl<uint64_t> &Record,
 988                                unsigned Abbrev) {
 989   Record.push_back(N->isDistinct());
 990   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 991   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 992   Record.push_back(N->getLine());
 993   Record.push_back(N->getColumn());
 994
 995   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
 996   Record.clear();
 997 }
 998
 999 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *N,
1000                                     const ValueEnumerator &VE,
1001                                     BitstreamWriter &Stream,
1002                                     SmallVectorImpl<uint64_t> &Record,
1003                                     unsigned Abbrev) {
1004   Record.push_back(N->isDistinct());
1005   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1006   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1007   Record.push_back(N->getDiscriminator());
1008
1009   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1010   Record.clear();
1011 }
1012
1013 static void WriteMDNamespace(const MDNamespace *N, const ValueEnumerator &VE,
1014                              BitstreamWriter &Stream,
1015                              SmallVectorImpl<uint64_t> &Record,
1016                              unsigned Abbrev) {
1017   Record.push_back(N->isDistinct());
1018   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1019   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1020   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1021   Record.push_back(N->getLine());
1022
1023   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1024   Record.clear();
1025 }
1026
1027 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *N,
1028                                          const ValueEnumerator &VE,
1029                                          BitstreamWriter &Stream,
1030                                          SmallVectorImpl<uint64_t> &Record,
1031                                          unsigned Abbrev) {
1032   Record.push_back(N->isDistinct());
1033   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1034   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1035
1036   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1037   Record.clear();
1038 }
1039
1040 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *N,
1041                                           const ValueEnumerator &VE,
1042                                           BitstreamWriter &Stream,
1043                                           SmallVectorImpl<uint64_t> &Record,
1044                                           unsigned Abbrev) {
1045   Record.push_back(N->isDistinct());
1046   Record.push_back(N->getTag());
1047   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1048   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1049   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1050
1051   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1052   Record.clear();
1053 }
1054
1055 static void WriteMDGlobalVariable(const MDGlobalVariable *N,
1056                                   const ValueEnumerator &VE,
1057                                   BitstreamWriter &Stream,
1058                                   SmallVectorImpl<uint64_t> &Record,
1059                                   unsigned Abbrev) {
1060   Record.push_back(N->isDistinct());
1061   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1062   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1063   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1064   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1065   Record.push_back(N->getLine());
1066   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1067   Record.push_back(N->isLocalToUnit());
1068   Record.push_back(N->isDefinition());
1069   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1070   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1071
1072   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1073   Record.clear();
1074 }
1075
1076 static void WriteMDLocalVariable(const MDLocalVariable *N,
1077                                  const ValueEnumerator &VE,
1078                                  BitstreamWriter &Stream,
1079                                  SmallVectorImpl<uint64_t> &Record,
1080                                  unsigned Abbrev) {
1081   Record.push_back(N->isDistinct());
1082   Record.push_back(N->getTag());
1083   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1084   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1085   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1086   Record.push_back(N->getLine());
1087   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1088   Record.push_back(N->getArg());
1089   Record.push_back(N->getFlags());
1090
1091   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1092   Record.clear();
1093 }
1094
1095 static void WriteMDExpression(const MDExpression *N, const ValueEnumerator &,
1096                               BitstreamWriter &Stream,
1097                               SmallVectorImpl<uint64_t> &Record,
1098                               unsigned Abbrev) {
1099   Record.reserve(N->getElements().size() + 1);
1100
1101   Record.push_back(N->isDistinct());
1102   Record.append(N->elements_begin(), N->elements_end());
1103
1104   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1105   Record.clear();
1106 }
1107
1108 static void WriteMDObjCProperty(const MDObjCProperty *N,
1109                                  const ValueEnumerator &VE,
1110                                  BitstreamWriter &Stream,
1111                                  SmallVectorImpl<uint64_t> &Record,
1112                                  unsigned Abbrev) {
1113   Record.push_back(N->isDistinct());
1114   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1115   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1116   Record.push_back(N->getLine());
1117   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1118   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1119   Record.push_back(N->getAttributes());
1120   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1121
1122   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1123   Record.clear();
1124 }
1125
1126 static void WriteMDImportedEntity(const MDImportedEntity *N,
1127                                   const ValueEnumerator &VE,
1128                                   BitstreamWriter &Stream,
1129                                   SmallVectorImpl<uint64_t> &Record,
1130                                   unsigned Abbrev) {
1131   Record.push_back(N->isDistinct());
1132   Record.push_back(N->getTag());
1133   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1134   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1135   Record.push_back(N->getLine());
1136   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1137
1138   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1139   Record.clear();
1140 }
1141
1142 static void WriteModuleMetadata(const Module *M,
1143                                 const ValueEnumerator &VE,
1144                                 BitstreamWriter &Stream) {
1145   const auto &MDs = VE.getMDs();
1146   if (MDs.empty() && M->named_metadata_empty())
1147     return;
1148
1149   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1150
1151   unsigned MDSAbbrev = 0;
1152   if (VE.hasMDString()) {
1153     // Abbrev for METADATA_STRING.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1158     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1159   }
1160
1161   // Initialize MDNode abbreviations.
1162 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1163 #include "llvm/IR/Metadata.def"
1164
1165   if (VE.hasMDLocation()) {
1166     // Abbrev for METADATA_LOCATION.
1167     //
1168     // Assume the column is usually under 128, and always output the inlined-at
1169     // location (it's never more expensive than building an array size 1).
1170     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1171     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1172     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1174     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1177     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
1178   }
1179
1180   if (VE.hasGenericDebugNode()) {
1181     // Abbrev for METADATA_GENERIC_DEBUG.
1182     //
1183     // Assume the column is usually under 128, and always output the inlined-at
1184     // location (it's never more expensive than building an array size 1).
1185     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1186     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1193     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1194   }
1195
1196   unsigned NameAbbrev = 0;
1197   if (!M->named_metadata_empty()) {
1198     // Abbrev for METADATA_NAME.
1199     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1200     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1201     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1202     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1203     NameAbbrev = Stream.EmitAbbrev(Abbv);
1204   }
1205
1206   SmallVector<uint64_t, 64> Record;
1207   for (const Metadata *MD : MDs) {
1208     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1209       assert(N->isResolved() && "Expected forward references to be resolved");
1210
1211       switch (N->getMetadataID()) {
1212       default:
1213         llvm_unreachable("Invalid MDNode subclass");
1214 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1215   case Metadata::CLASS##Kind:                                                  \
1216     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1217     continue;
1218 #include "llvm/IR/Metadata.def"
1219       }
1220     }
1221     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1222       WriteValueAsMetadata(MDC, VE, Stream, Record);
1223       continue;
1224     }
1225     const MDString *MDS = cast<MDString>(MD);
1226     // Code: [strchar x N]
1227     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1228
1229     // Emit the finished record.
1230     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1231     Record.clear();
1232   }
1233
1234   // Write named metadata.
1235   for (const NamedMDNode &NMD : M->named_metadata()) {
1236     // Write name.
1237     StringRef Str = NMD.getName();
1238     Record.append(Str.bytes_begin(), Str.bytes_end());
1239     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1240     Record.clear();
1241
1242     // Write named metadata operands.
1243     for (const MDNode *N : NMD.operands())
1244       Record.push_back(VE.getMetadataID(N));
1245     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1246     Record.clear();
1247   }
1248
1249   Stream.ExitBlock();
1250 }
1251
1252 static void WriteFunctionLocalMetadata(const Function &F,
1253                                        const ValueEnumerator &VE,
1254                                        BitstreamWriter &Stream) {
1255   bool StartedMetadataBlock = false;
1256   SmallVector<uint64_t, 64> Record;
1257   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1258       VE.getFunctionLocalMDs();
1259   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1260     assert(MDs[i] && "Expected valid function-local metadata");
1261     if (!StartedMetadataBlock) {
1262       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1263       StartedMetadataBlock = true;
1264     }
1265     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1266   }
1267
1268   if (StartedMetadataBlock)
1269     Stream.ExitBlock();
1270 }
1271
1272 static void WriteMetadataAttachment(const Function &F,
1273                                     const ValueEnumerator &VE,
1274                                     BitstreamWriter &Stream) {
1275   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1276
1277   SmallVector<uint64_t, 64> Record;
1278
1279   // Write metadata attachments
1280   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1281   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1282
1283   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1284     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1285          I != E; ++I) {
1286       MDs.clear();
1287       I->getAllMetadataOtherThanDebugLoc(MDs);
1288
1289       // If no metadata, ignore instruction.
1290       if (MDs.empty()) continue;
1291
1292       Record.push_back(VE.getInstructionID(I));
1293
1294       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1295         Record.push_back(MDs[i].first);
1296         Record.push_back(VE.getMetadataID(MDs[i].second));
1297       }
1298       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1299       Record.clear();
1300     }
1301
1302   Stream.ExitBlock();
1303 }
1304
1305 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1306   SmallVector<uint64_t, 64> Record;
1307
1308   // Write metadata kinds
1309   // METADATA_KIND - [n x [id, name]]
1310   SmallVector<StringRef, 8> Names;
1311   M->getMDKindNames(Names);
1312
1313   if (Names.empty()) return;
1314
1315   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1316
1317   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1318     Record.push_back(MDKindID);
1319     StringRef KName = Names[MDKindID];
1320     Record.append(KName.begin(), KName.end());
1321
1322     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1323     Record.clear();
1324   }
1325
1326   Stream.ExitBlock();
1327 }
1328
1329 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1330   if ((int64_t)V >= 0)
1331     Vals.push_back(V << 1);
1332   else
1333     Vals.push_back((-V << 1) | 1);
1334 }
1335
1336 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1337                            const ValueEnumerator &VE,
1338                            BitstreamWriter &Stream, bool isGlobal) {
1339   if (FirstVal == LastVal) return;
1340
1341   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1342
1343   unsigned AggregateAbbrev = 0;
1344   unsigned String8Abbrev = 0;
1345   unsigned CString7Abbrev = 0;
1346   unsigned CString6Abbrev = 0;
1347   // If this is a constant pool for the module, emit module-specific abbrevs.
1348   if (isGlobal) {
1349     // Abbrev for CST_CODE_AGGREGATE.
1350     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1351     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1354     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1355
1356     // Abbrev for CST_CODE_STRING.
1357     Abbv = new BitCodeAbbrev();
1358     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1361     String8Abbrev = Stream.EmitAbbrev(Abbv);
1362     // Abbrev for CST_CODE_CSTRING.
1363     Abbv = new BitCodeAbbrev();
1364     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1367     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1368     // Abbrev for CST_CODE_CSTRING.
1369     Abbv = new BitCodeAbbrev();
1370     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1373     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1374   }
1375
1376   SmallVector<uint64_t, 64> Record;
1377
1378   const ValueEnumerator::ValueList &Vals = VE.getValues();
1379   Type *LastTy = nullptr;
1380   for (unsigned i = FirstVal; i != LastVal; ++i) {
1381     const Value *V = Vals[i].first;
1382     // If we need to switch types, do so now.
1383     if (V->getType() != LastTy) {
1384       LastTy = V->getType();
1385       Record.push_back(VE.getTypeID(LastTy));
1386       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1387                         CONSTANTS_SETTYPE_ABBREV);
1388       Record.clear();
1389     }
1390
1391     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1392       Record.push_back(unsigned(IA->hasSideEffects()) |
1393                        unsigned(IA->isAlignStack()) << 1 |
1394                        unsigned(IA->getDialect()&1) << 2);
1395
1396       // Add the asm string.
1397       const std::string &AsmStr = IA->getAsmString();
1398       Record.push_back(AsmStr.size());
1399       Record.append(AsmStr.begin(), AsmStr.end());
1400
1401       // Add the constraint string.
1402       const std::string &ConstraintStr = IA->getConstraintString();
1403       Record.push_back(ConstraintStr.size());
1404       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1405       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1406       Record.clear();
1407       continue;
1408     }
1409     const Constant *C = cast<Constant>(V);
1410     unsigned Code = -1U;
1411     unsigned AbbrevToUse = 0;
1412     if (C->isNullValue()) {
1413       Code = bitc::CST_CODE_NULL;
1414     } else if (isa<UndefValue>(C)) {
1415       Code = bitc::CST_CODE_UNDEF;
1416     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1417       if (IV->getBitWidth() <= 64) {
1418         uint64_t V = IV->getSExtValue();
1419         emitSignedInt64(Record, V);
1420         Code = bitc::CST_CODE_INTEGER;
1421         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1422       } else {                             // Wide integers, > 64 bits in size.
1423         // We have an arbitrary precision integer value to write whose
1424         // bit width is > 64. However, in canonical unsigned integer
1425         // format it is likely that the high bits are going to be zero.
1426         // So, we only write the number of active words.
1427         unsigned NWords = IV->getValue().getActiveWords();
1428         const uint64_t *RawWords = IV->getValue().getRawData();
1429         for (unsigned i = 0; i != NWords; ++i) {
1430           emitSignedInt64(Record, RawWords[i]);
1431         }
1432         Code = bitc::CST_CODE_WIDE_INTEGER;
1433       }
1434     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1435       Code = bitc::CST_CODE_FLOAT;
1436       Type *Ty = CFP->getType();
1437       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1438         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1439       } else if (Ty->isX86_FP80Ty()) {
1440         // api needed to prevent premature destruction
1441         // bits are not in the same order as a normal i80 APInt, compensate.
1442         APInt api = CFP->getValueAPF().bitcastToAPInt();
1443         const uint64_t *p = api.getRawData();
1444         Record.push_back((p[1] << 48) | (p[0] >> 16));
1445         Record.push_back(p[0] & 0xffffLL);
1446       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1447         APInt api = CFP->getValueAPF().bitcastToAPInt();
1448         const uint64_t *p = api.getRawData();
1449         Record.push_back(p[0]);
1450         Record.push_back(p[1]);
1451       } else {
1452         assert (0 && "Unknown FP type!");
1453       }
1454     } else if (isa<ConstantDataSequential>(C) &&
1455                cast<ConstantDataSequential>(C)->isString()) {
1456       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1457       // Emit constant strings specially.
1458       unsigned NumElts = Str->getNumElements();
1459       // If this is a null-terminated string, use the denser CSTRING encoding.
1460       if (Str->isCString()) {
1461         Code = bitc::CST_CODE_CSTRING;
1462         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1463       } else {
1464         Code = bitc::CST_CODE_STRING;
1465         AbbrevToUse = String8Abbrev;
1466       }
1467       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1468       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1469       for (unsigned i = 0; i != NumElts; ++i) {
1470         unsigned char V = Str->getElementAsInteger(i);
1471         Record.push_back(V);
1472         isCStr7 &= (V & 128) == 0;
1473         if (isCStrChar6)
1474           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1475       }
1476
1477       if (isCStrChar6)
1478         AbbrevToUse = CString6Abbrev;
1479       else if (isCStr7)
1480         AbbrevToUse = CString7Abbrev;
1481     } else if (const ConstantDataSequential *CDS =
1482                   dyn_cast<ConstantDataSequential>(C)) {
1483       Code = bitc::CST_CODE_DATA;
1484       Type *EltTy = CDS->getType()->getElementType();
1485       if (isa<IntegerType>(EltTy)) {
1486         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1487           Record.push_back(CDS->getElementAsInteger(i));
1488       } else if (EltTy->isFloatTy()) {
1489         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1490           union { float F; uint32_t I; };
1491           F = CDS->getElementAsFloat(i);
1492           Record.push_back(I);
1493         }
1494       } else {
1495         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1496         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1497           union { double F; uint64_t I; };
1498           F = CDS->getElementAsDouble(i);
1499           Record.push_back(I);
1500         }
1501       }
1502     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1503                isa<ConstantVector>(C)) {
1504       Code = bitc::CST_CODE_AGGREGATE;
1505       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1506         Record.push_back(VE.getValueID(C->getOperand(i)));
1507       AbbrevToUse = AggregateAbbrev;
1508     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1509       switch (CE->getOpcode()) {
1510       default:
1511         if (Instruction::isCast(CE->getOpcode())) {
1512           Code = bitc::CST_CODE_CE_CAST;
1513           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1514           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1515           Record.push_back(VE.getValueID(C->getOperand(0)));
1516           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1517         } else {
1518           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1519           Code = bitc::CST_CODE_CE_BINOP;
1520           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1521           Record.push_back(VE.getValueID(C->getOperand(0)));
1522           Record.push_back(VE.getValueID(C->getOperand(1)));
1523           uint64_t Flags = GetOptimizationFlags(CE);
1524           if (Flags != 0)
1525             Record.push_back(Flags);
1526         }
1527         break;
1528       case Instruction::GetElementPtr: {
1529         Code = bitc::CST_CODE_CE_GEP;
1530         const auto *GO = cast<GEPOperator>(C);
1531         if (GO->isInBounds())
1532           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1533         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1534         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1535           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1536           Record.push_back(VE.getValueID(C->getOperand(i)));
1537         }
1538         break;
1539       }
1540       case Instruction::Select:
1541         Code = bitc::CST_CODE_CE_SELECT;
1542         Record.push_back(VE.getValueID(C->getOperand(0)));
1543         Record.push_back(VE.getValueID(C->getOperand(1)));
1544         Record.push_back(VE.getValueID(C->getOperand(2)));
1545         break;
1546       case Instruction::ExtractElement:
1547         Code = bitc::CST_CODE_CE_EXTRACTELT;
1548         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1549         Record.push_back(VE.getValueID(C->getOperand(0)));
1550         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1551         Record.push_back(VE.getValueID(C->getOperand(1)));
1552         break;
1553       case Instruction::InsertElement:
1554         Code = bitc::CST_CODE_CE_INSERTELT;
1555         Record.push_back(VE.getValueID(C->getOperand(0)));
1556         Record.push_back(VE.getValueID(C->getOperand(1)));
1557         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1558         Record.push_back(VE.getValueID(C->getOperand(2)));
1559         break;
1560       case Instruction::ShuffleVector:
1561         // If the return type and argument types are the same, this is a
1562         // standard shufflevector instruction.  If the types are different,
1563         // then the shuffle is widening or truncating the input vectors, and
1564         // the argument type must also be encoded.
1565         if (C->getType() == C->getOperand(0)->getType()) {
1566           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1567         } else {
1568           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1569           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1570         }
1571         Record.push_back(VE.getValueID(C->getOperand(0)));
1572         Record.push_back(VE.getValueID(C->getOperand(1)));
1573         Record.push_back(VE.getValueID(C->getOperand(2)));
1574         break;
1575       case Instruction::ICmp:
1576       case Instruction::FCmp:
1577         Code = bitc::CST_CODE_CE_CMP;
1578         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1579         Record.push_back(VE.getValueID(C->getOperand(0)));
1580         Record.push_back(VE.getValueID(C->getOperand(1)));
1581         Record.push_back(CE->getPredicate());
1582         break;
1583       }
1584     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1585       Code = bitc::CST_CODE_BLOCKADDRESS;
1586       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1587       Record.push_back(VE.getValueID(BA->getFunction()));
1588       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1589     } else {
1590 #ifndef NDEBUG
1591       C->dump();
1592 #endif
1593       llvm_unreachable("Unknown constant!");
1594     }
1595     Stream.EmitRecord(Code, Record, AbbrevToUse);
1596     Record.clear();
1597   }
1598
1599   Stream.ExitBlock();
1600 }
1601
1602 static void WriteModuleConstants(const ValueEnumerator &VE,
1603                                  BitstreamWriter &Stream) {
1604   const ValueEnumerator::ValueList &Vals = VE.getValues();
1605
1606   // Find the first constant to emit, which is the first non-globalvalue value.
1607   // We know globalvalues have been emitted by WriteModuleInfo.
1608   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1609     if (!isa<GlobalValue>(Vals[i].first)) {
1610       WriteConstants(i, Vals.size(), VE, Stream, true);
1611       return;
1612     }
1613   }
1614 }
1615
1616 /// PushValueAndType - The file has to encode both the value and type id for
1617 /// many values, because we need to know what type to create for forward
1618 /// references.  However, most operands are not forward references, so this type
1619 /// field is not needed.
1620 ///
1621 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1622 /// instruction ID, then it is a forward reference, and it also includes the
1623 /// type ID.  The value ID that is written is encoded relative to the InstID.
1624 static bool PushValueAndType(const Value *V, unsigned InstID,
1625                              SmallVectorImpl<unsigned> &Vals,
1626                              ValueEnumerator &VE) {
1627   unsigned ValID = VE.getValueID(V);
1628   // Make encoding relative to the InstID.
1629   Vals.push_back(InstID - ValID);
1630   if (ValID >= InstID) {
1631     Vals.push_back(VE.getTypeID(V->getType()));
1632     return true;
1633   }
1634   return false;
1635 }
1636
1637 /// pushValue - Like PushValueAndType, but where the type of the value is
1638 /// omitted (perhaps it was already encoded in an earlier operand).
1639 static void pushValue(const Value *V, unsigned InstID,
1640                       SmallVectorImpl<unsigned> &Vals,
1641                       ValueEnumerator &VE) {
1642   unsigned ValID = VE.getValueID(V);
1643   Vals.push_back(InstID - ValID);
1644 }
1645
1646 static void pushValueSigned(const Value *V, unsigned InstID,
1647                             SmallVectorImpl<uint64_t> &Vals,
1648                             ValueEnumerator &VE) {
1649   unsigned ValID = VE.getValueID(V);
1650   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1651   emitSignedInt64(Vals, diff);
1652 }
1653
1654 /// WriteInstruction - Emit an instruction to the specified stream.
1655 static void WriteInstruction(const Instruction &I, unsigned InstID,
1656                              ValueEnumerator &VE, BitstreamWriter &Stream,
1657                              SmallVectorImpl<unsigned> &Vals) {
1658   unsigned Code = 0;
1659   unsigned AbbrevToUse = 0;
1660   VE.setInstructionID(&I);
1661   switch (I.getOpcode()) {
1662   default:
1663     if (Instruction::isCast(I.getOpcode())) {
1664       Code = bitc::FUNC_CODE_INST_CAST;
1665       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1666         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1667       Vals.push_back(VE.getTypeID(I.getType()));
1668       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1669     } else {
1670       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1671       Code = bitc::FUNC_CODE_INST_BINOP;
1672       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1673         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1674       pushValue(I.getOperand(1), InstID, Vals, VE);
1675       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1676       uint64_t Flags = GetOptimizationFlags(&I);
1677       if (Flags != 0) {
1678         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1679           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1680         Vals.push_back(Flags);
1681       }
1682     }
1683     break;
1684
1685   case Instruction::GetElementPtr: {
1686     Code = bitc::FUNC_CODE_INST_GEP;
1687     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1688     auto &GEPInst = cast<GetElementPtrInst>(I);
1689     Vals.push_back(GEPInst.isInBounds());
1690     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1691     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1692       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1693     break;
1694   }
1695   case Instruction::ExtractValue: {
1696     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1697     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1698     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1699     Vals.append(EVI->idx_begin(), EVI->idx_end());
1700     break;
1701   }
1702   case Instruction::InsertValue: {
1703     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1704     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1705     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1706     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1707     Vals.append(IVI->idx_begin(), IVI->idx_end());
1708     break;
1709   }
1710   case Instruction::Select:
1711     Code = bitc::FUNC_CODE_INST_VSELECT;
1712     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1713     pushValue(I.getOperand(2), InstID, Vals, VE);
1714     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1715     break;
1716   case Instruction::ExtractElement:
1717     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1718     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1719     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1720     break;
1721   case Instruction::InsertElement:
1722     Code = bitc::FUNC_CODE_INST_INSERTELT;
1723     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1724     pushValue(I.getOperand(1), InstID, Vals, VE);
1725     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1726     break;
1727   case Instruction::ShuffleVector:
1728     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1729     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1730     pushValue(I.getOperand(1), InstID, Vals, VE);
1731     pushValue(I.getOperand(2), InstID, Vals, VE);
1732     break;
1733   case Instruction::ICmp:
1734   case Instruction::FCmp:
1735     // compare returning Int1Ty or vector of Int1Ty
1736     Code = bitc::FUNC_CODE_INST_CMP2;
1737     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1738     pushValue(I.getOperand(1), InstID, Vals, VE);
1739     Vals.push_back(cast<CmpInst>(I).getPredicate());
1740     break;
1741
1742   case Instruction::Ret:
1743     {
1744       Code = bitc::FUNC_CODE_INST_RET;
1745       unsigned NumOperands = I.getNumOperands();
1746       if (NumOperands == 0)
1747         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1748       else if (NumOperands == 1) {
1749         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1750           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1751       } else {
1752         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1753           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1754       }
1755     }
1756     break;
1757   case Instruction::Br:
1758     {
1759       Code = bitc::FUNC_CODE_INST_BR;
1760       const BranchInst &II = cast<BranchInst>(I);
1761       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1762       if (II.isConditional()) {
1763         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1764         pushValue(II.getCondition(), InstID, Vals, VE);
1765       }
1766     }
1767     break;
1768   case Instruction::Switch:
1769     {
1770       Code = bitc::FUNC_CODE_INST_SWITCH;
1771       const SwitchInst &SI = cast<SwitchInst>(I);
1772       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1773       pushValue(SI.getCondition(), InstID, Vals, VE);
1774       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1775       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1776            i != e; ++i) {
1777         Vals.push_back(VE.getValueID(i.getCaseValue()));
1778         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1779       }
1780     }
1781     break;
1782   case Instruction::IndirectBr:
1783     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1784     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1785     // Encode the address operand as relative, but not the basic blocks.
1786     pushValue(I.getOperand(0), InstID, Vals, VE);
1787     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1788       Vals.push_back(VE.getValueID(I.getOperand(i)));
1789     break;
1790
1791   case Instruction::Invoke: {
1792     const InvokeInst *II = cast<InvokeInst>(&I);
1793     const Value *Callee(II->getCalledValue());
1794     PointerType *PTy = cast<PointerType>(Callee->getType());
1795     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1796     Code = bitc::FUNC_CODE_INST_INVOKE;
1797
1798     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1799     Vals.push_back(II->getCallingConv());
1800     Vals.push_back(VE.getValueID(II->getNormalDest()));
1801     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1802     PushValueAndType(Callee, InstID, Vals, VE);
1803
1804     // Emit value #'s for the fixed parameters.
1805     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1806       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1807
1808     // Emit type/value pairs for varargs params.
1809     if (FTy->isVarArg()) {
1810       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1811            i != e; ++i)
1812         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1813     }
1814     break;
1815   }
1816   case Instruction::Resume:
1817     Code = bitc::FUNC_CODE_INST_RESUME;
1818     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1819     break;
1820   case Instruction::Unreachable:
1821     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1822     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1823     break;
1824
1825   case Instruction::PHI: {
1826     const PHINode &PN = cast<PHINode>(I);
1827     Code = bitc::FUNC_CODE_INST_PHI;
1828     // With the newer instruction encoding, forward references could give
1829     // negative valued IDs.  This is most common for PHIs, so we use
1830     // signed VBRs.
1831     SmallVector<uint64_t, 128> Vals64;
1832     Vals64.push_back(VE.getTypeID(PN.getType()));
1833     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1834       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1835       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1836     }
1837     // Emit a Vals64 vector and exit.
1838     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1839     Vals64.clear();
1840     return;
1841   }
1842
1843   case Instruction::LandingPad: {
1844     const LandingPadInst &LP = cast<LandingPadInst>(I);
1845     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1846     Vals.push_back(VE.getTypeID(LP.getType()));
1847     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1848     Vals.push_back(LP.isCleanup());
1849     Vals.push_back(LP.getNumClauses());
1850     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1851       if (LP.isCatch(I))
1852         Vals.push_back(LandingPadInst::Catch);
1853       else
1854         Vals.push_back(LandingPadInst::Filter);
1855       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1856     }
1857     break;
1858   }
1859
1860   case Instruction::Alloca: {
1861     Code = bitc::FUNC_CODE_INST_ALLOCA;
1862     Vals.push_back(VE.getTypeID(I.getType()));
1863     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1864     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1865     const AllocaInst &AI = cast<AllocaInst>(I);
1866     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1867     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1868            "not enough bits for maximum alignment");
1869     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1870     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1871     Vals.push_back(AlignRecord);
1872     break;
1873   }
1874
1875   case Instruction::Load:
1876     if (cast<LoadInst>(I).isAtomic()) {
1877       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1878       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1879     } else {
1880       Code = bitc::FUNC_CODE_INST_LOAD;
1881       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1882         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1883     }
1884     Vals.push_back(VE.getTypeID(I.getType()));
1885     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1886     Vals.push_back(cast<LoadInst>(I).isVolatile());
1887     if (cast<LoadInst>(I).isAtomic()) {
1888       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1889       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1890     }
1891     break;
1892   case Instruction::Store:
1893     if (cast<StoreInst>(I).isAtomic())
1894       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1895     else
1896       Code = bitc::FUNC_CODE_INST_STORE;
1897     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1898     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1899     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1900     Vals.push_back(cast<StoreInst>(I).isVolatile());
1901     if (cast<StoreInst>(I).isAtomic()) {
1902       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1903       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1904     }
1905     break;
1906   case Instruction::AtomicCmpXchg:
1907     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1908     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1909     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1910     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1911     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1912     Vals.push_back(GetEncodedOrdering(
1913                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1914     Vals.push_back(GetEncodedSynchScope(
1915                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1916     Vals.push_back(GetEncodedOrdering(
1917                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1918     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1919     break;
1920   case Instruction::AtomicRMW:
1921     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1922     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1923     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1924     Vals.push_back(GetEncodedRMWOperation(
1925                      cast<AtomicRMWInst>(I).getOperation()));
1926     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1927     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1928     Vals.push_back(GetEncodedSynchScope(
1929                      cast<AtomicRMWInst>(I).getSynchScope()));
1930     break;
1931   case Instruction::Fence:
1932     Code = bitc::FUNC_CODE_INST_FENCE;
1933     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1934     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1935     break;
1936   case Instruction::Call: {
1937     const CallInst &CI = cast<CallInst>(I);
1938     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1939     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1940
1941     Code = bitc::FUNC_CODE_INST_CALL;
1942
1943     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1944     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1945                    unsigned(CI.isMustTailCall()) << 14);
1946     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1947
1948     // Emit value #'s for the fixed parameters.
1949     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1950       // Check for labels (can happen with asm labels).
1951       if (FTy->getParamType(i)->isLabelTy())
1952         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1953       else
1954         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1955     }
1956
1957     // Emit type/value pairs for varargs params.
1958     if (FTy->isVarArg()) {
1959       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1960            i != e; ++i)
1961         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1962     }
1963     break;
1964   }
1965   case Instruction::VAArg:
1966     Code = bitc::FUNC_CODE_INST_VAARG;
1967     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1968     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1969     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1970     break;
1971   }
1972
1973   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1974   Vals.clear();
1975 }
1976
1977 // Emit names for globals/functions etc.
1978 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1979                                   const ValueEnumerator &VE,
1980                                   BitstreamWriter &Stream) {
1981   if (VST.empty()) return;
1982   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1983
1984   // FIXME: Set up the abbrev, we know how many values there are!
1985   // FIXME: We know if the type names can use 7-bit ascii.
1986   SmallVector<unsigned, 64> NameVals;
1987
1988   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1989        SI != SE; ++SI) {
1990
1991     const ValueName &Name = *SI;
1992
1993     // Figure out the encoding to use for the name.
1994     bool is7Bit = true;
1995     bool isChar6 = true;
1996     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1997          C != E; ++C) {
1998       if (isChar6)
1999         isChar6 = BitCodeAbbrevOp::isChar6(*C);
2000       if ((unsigned char)*C & 128) {
2001         is7Bit = false;
2002         break;  // don't bother scanning the rest.
2003       }
2004     }
2005
2006     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2007
2008     // VST_ENTRY:   [valueid, namechar x N]
2009     // VST_BBENTRY: [bbid, namechar x N]
2010     unsigned Code;
2011     if (isa<BasicBlock>(SI->getValue())) {
2012       Code = bitc::VST_CODE_BBENTRY;
2013       if (isChar6)
2014         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2015     } else {
2016       Code = bitc::VST_CODE_ENTRY;
2017       if (isChar6)
2018         AbbrevToUse = VST_ENTRY_6_ABBREV;
2019       else if (is7Bit)
2020         AbbrevToUse = VST_ENTRY_7_ABBREV;
2021     }
2022
2023     NameVals.push_back(VE.getValueID(SI->getValue()));
2024     for (const char *P = Name.getKeyData(),
2025          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2026       NameVals.push_back((unsigned char)*P);
2027
2028     // Emit the finished record.
2029     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2030     NameVals.clear();
2031   }
2032   Stream.ExitBlock();
2033 }
2034
2035 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2036                          BitstreamWriter &Stream) {
2037   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2038   unsigned Code;
2039   if (isa<BasicBlock>(Order.V))
2040     Code = bitc::USELIST_CODE_BB;
2041   else
2042     Code = bitc::USELIST_CODE_DEFAULT;
2043
2044   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2045   Record.push_back(VE.getValueID(Order.V));
2046   Stream.EmitRecord(Code, Record);
2047 }
2048
2049 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2050                               BitstreamWriter &Stream) {
2051   assert(VE.shouldPreserveUseListOrder() &&
2052          "Expected to be preserving use-list order");
2053
2054   auto hasMore = [&]() {
2055     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2056   };
2057   if (!hasMore())
2058     // Nothing to do.
2059     return;
2060
2061   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2062   while (hasMore()) {
2063     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2064     VE.UseListOrders.pop_back();
2065   }
2066   Stream.ExitBlock();
2067 }
2068
2069 /// WriteFunction - Emit a function body to the module stream.
2070 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2071                           BitstreamWriter &Stream) {
2072   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2073   VE.incorporateFunction(F);
2074
2075   SmallVector<unsigned, 64> Vals;
2076
2077   // Emit the number of basic blocks, so the reader can create them ahead of
2078   // time.
2079   Vals.push_back(VE.getBasicBlocks().size());
2080   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2081   Vals.clear();
2082
2083   // If there are function-local constants, emit them now.
2084   unsigned CstStart, CstEnd;
2085   VE.getFunctionConstantRange(CstStart, CstEnd);
2086   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2087
2088   // If there is function-local metadata, emit it now.
2089   WriteFunctionLocalMetadata(F, VE, Stream);
2090
2091   // Keep a running idea of what the instruction ID is.
2092   unsigned InstID = CstEnd;
2093
2094   bool NeedsMetadataAttachment = false;
2095
2096   MDLocation *LastDL = nullptr;
2097
2098   // Finally, emit all the instructions, in order.
2099   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2100     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2101          I != E; ++I) {
2102       WriteInstruction(*I, InstID, VE, Stream, Vals);
2103
2104       if (!I->getType()->isVoidTy())
2105         ++InstID;
2106
2107       // If the instruction has metadata, write a metadata attachment later.
2108       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2109
2110       // If the instruction has a debug location, emit it.
2111       MDLocation *DL = I->getDebugLoc();
2112       if (!DL)
2113         continue;
2114
2115       if (DL == LastDL) {
2116         // Just repeat the same debug loc as last time.
2117         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2118         continue;
2119       }
2120
2121       Vals.push_back(DL->getLine());
2122       Vals.push_back(DL->getColumn());
2123       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2124       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2125       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2126       Vals.clear();
2127     }
2128
2129   // Emit names for all the instructions etc.
2130   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2131
2132   if (NeedsMetadataAttachment)
2133     WriteMetadataAttachment(F, VE, Stream);
2134   if (VE.shouldPreserveUseListOrder())
2135     WriteUseListBlock(&F, VE, Stream);
2136   VE.purgeFunction();
2137   Stream.ExitBlock();
2138 }
2139
2140 // Emit blockinfo, which defines the standard abbreviations etc.
2141 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2142   // We only want to emit block info records for blocks that have multiple
2143   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2144   // Other blocks can define their abbrevs inline.
2145   Stream.EnterBlockInfoBlock(2);
2146
2147   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2148     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2151     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2152     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2153     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2154                                    Abbv) != VST_ENTRY_8_ABBREV)
2155       llvm_unreachable("Unexpected abbrev ordering!");
2156   }
2157
2158   { // 7-bit fixed width VST_ENTRY strings.
2159     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2160     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2161     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2162     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2164     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2165                                    Abbv) != VST_ENTRY_7_ABBREV)
2166       llvm_unreachable("Unexpected abbrev ordering!");
2167   }
2168   { // 6-bit char6 VST_ENTRY strings.
2169     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2170     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2171     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2172     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2174     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2175                                    Abbv) != VST_ENTRY_6_ABBREV)
2176       llvm_unreachable("Unexpected abbrev ordering!");
2177   }
2178   { // 6-bit char6 VST_BBENTRY strings.
2179     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2180     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2181     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2182     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2184     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2185                                    Abbv) != VST_BBENTRY_6_ABBREV)
2186       llvm_unreachable("Unexpected abbrev ordering!");
2187   }
2188
2189
2190
2191   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2192     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2193     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2195                               VE.computeBitsRequiredForTypeIndicies()));
2196     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2197                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2198       llvm_unreachable("Unexpected abbrev ordering!");
2199   }
2200
2201   { // INTEGER abbrev for CONSTANTS_BLOCK.
2202     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2203     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2205     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2206                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2207       llvm_unreachable("Unexpected abbrev ordering!");
2208   }
2209
2210   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2211     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2212     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2214     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2215                               VE.computeBitsRequiredForTypeIndicies()));
2216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2217
2218     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2219                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2220       llvm_unreachable("Unexpected abbrev ordering!");
2221   }
2222   { // NULL abbrev for CONSTANTS_BLOCK.
2223     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2224     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2225     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2226                                    Abbv) != CONSTANTS_NULL_Abbrev)
2227       llvm_unreachable("Unexpected abbrev ordering!");
2228   }
2229
2230   // FIXME: This should only use space for first class types!
2231
2232   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2233     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2234     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2237                               VE.computeBitsRequiredForTypeIndicies()));
2238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2240     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2241                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2242       llvm_unreachable("Unexpected abbrev ordering!");
2243   }
2244   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2245     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2246     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2250     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2251                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2252       llvm_unreachable("Unexpected abbrev ordering!");
2253   }
2254   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2255     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2256     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2257     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2261     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2262                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2263       llvm_unreachable("Unexpected abbrev ordering!");
2264   }
2265   { // INST_CAST abbrev for FUNCTION_BLOCK.
2266     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2267     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2270                               VE.computeBitsRequiredForTypeIndicies()));
2271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2272     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2273                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2274       llvm_unreachable("Unexpected abbrev ordering!");
2275   }
2276
2277   { // INST_RET abbrev for FUNCTION_BLOCK.
2278     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2279     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2280     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2281                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2282       llvm_unreachable("Unexpected abbrev ordering!");
2283   }
2284   { // INST_RET abbrev for FUNCTION_BLOCK.
2285     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2286     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2288     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2289                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2290       llvm_unreachable("Unexpected abbrev ordering!");
2291   }
2292   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2293     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2294     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2295     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2296                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2297       llvm_unreachable("Unexpected abbrev ordering!");
2298   }
2299   {
2300     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2301     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2304                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2307     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2308         FUNCTION_INST_GEP_ABBREV)
2309       llvm_unreachable("Unexpected abbrev ordering!");
2310   }
2311
2312   Stream.ExitBlock();
2313 }
2314
2315 /// WriteModule - Emit the specified module to the bitstream.
2316 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2317                         bool ShouldPreserveUseListOrder) {
2318   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2319
2320   SmallVector<unsigned, 1> Vals;
2321   unsigned CurVersion = 1;
2322   Vals.push_back(CurVersion);
2323   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2324
2325   // Analyze the module, enumerating globals, functions, etc.
2326   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2327
2328   // Emit blockinfo, which defines the standard abbreviations etc.
2329   WriteBlockInfo(VE, Stream);
2330
2331   // Emit information about attribute groups.
2332   WriteAttributeGroupTable(VE, Stream);
2333
2334   // Emit information about parameter attributes.
2335   WriteAttributeTable(VE, Stream);
2336
2337   // Emit information describing all of the types in the module.
2338   WriteTypeTable(VE, Stream);
2339
2340   writeComdats(VE, Stream);
2341
2342   // Emit top-level description of module, including target triple, inline asm,
2343   // descriptors for global variables, and function prototype info.
2344   WriteModuleInfo(M, VE, Stream);
2345
2346   // Emit constants.
2347   WriteModuleConstants(VE, Stream);
2348
2349   // Emit metadata.
2350   WriteModuleMetadata(M, VE, Stream);
2351
2352   // Emit metadata.
2353   WriteModuleMetadataStore(M, Stream);
2354
2355   // Emit names for globals/functions etc.
2356   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2357
2358   // Emit module-level use-lists.
2359   if (VE.shouldPreserveUseListOrder())
2360     WriteUseListBlock(nullptr, VE, Stream);
2361
2362   // Emit function bodies.
2363   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2364     if (!F->isDeclaration())
2365       WriteFunction(*F, VE, Stream);
2366
2367   Stream.ExitBlock();
2368 }
2369
2370 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2371 /// header and trailer to make it compatible with the system archiver.  To do
2372 /// this we emit the following header, and then emit a trailer that pads the
2373 /// file out to be a multiple of 16 bytes.
2374 ///
2375 /// struct bc_header {
2376 ///   uint32_t Magic;         // 0x0B17C0DE
2377 ///   uint32_t Version;       // Version, currently always 0.
2378 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2379 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2380 ///   uint32_t CPUType;       // CPU specifier.
2381 ///   ... potentially more later ...
2382 /// };
2383 enum {
2384   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2385   DarwinBCHeaderSize = 5*4
2386 };
2387
2388 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2389                                uint32_t &Position) {
2390   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2391   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2392   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2393   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2394   Position += 4;
2395 }
2396
2397 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2398                                          const Triple &TT) {
2399   unsigned CPUType = ~0U;
2400
2401   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2402   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2403   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2404   // specific constants here because they are implicitly part of the Darwin ABI.
2405   enum {
2406     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2407     DARWIN_CPU_TYPE_X86        = 7,
2408     DARWIN_CPU_TYPE_ARM        = 12,
2409     DARWIN_CPU_TYPE_POWERPC    = 18
2410   };
2411
2412   Triple::ArchType Arch = TT.getArch();
2413   if (Arch == Triple::x86_64)
2414     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2415   else if (Arch == Triple::x86)
2416     CPUType = DARWIN_CPU_TYPE_X86;
2417   else if (Arch == Triple::ppc)
2418     CPUType = DARWIN_CPU_TYPE_POWERPC;
2419   else if (Arch == Triple::ppc64)
2420     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2421   else if (Arch == Triple::arm || Arch == Triple::thumb)
2422     CPUType = DARWIN_CPU_TYPE_ARM;
2423
2424   // Traditional Bitcode starts after header.
2425   assert(Buffer.size() >= DarwinBCHeaderSize &&
2426          "Expected header size to be reserved");
2427   unsigned BCOffset = DarwinBCHeaderSize;
2428   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2429
2430   // Write the magic and version.
2431   unsigned Position = 0;
2432   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2433   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2434   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2435   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2436   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2437
2438   // If the file is not a multiple of 16 bytes, insert dummy padding.
2439   while (Buffer.size() & 15)
2440     Buffer.push_back(0);
2441 }
2442
2443 /// WriteBitcodeToFile - Write the specified module to the specified output
2444 /// stream.
2445 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2446                               bool ShouldPreserveUseListOrder) {
2447   SmallVector<char, 0> Buffer;
2448   Buffer.reserve(256*1024);
2449
2450   // If this is darwin or another generic macho target, reserve space for the
2451   // header.
2452   Triple TT(M->getTargetTriple());
2453   if (TT.isOSDarwin())
2454     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2455
2456   // Emit the module into the buffer.
2457   {
2458     BitstreamWriter Stream(Buffer);
2459
2460     // Emit the file header.
2461     Stream.Emit((unsigned)'B', 8);
2462     Stream.Emit((unsigned)'C', 8);
2463     Stream.Emit(0x0, 4);
2464     Stream.Emit(0xC, 4);
2465     Stream.Emit(0xE, 4);
2466     Stream.Emit(0xD, 4);
2467
2468     // Emit the module.
2469     WriteModule(M, Stream, ShouldPreserveUseListOrder);
2470   }
2471
2472   if (TT.isOSDarwin())
2473     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2474
2475   // Write the generated bitstream to "Out".
2476   Out.write((char*)&Buffer.front(), Buffer.size());
2477 }