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