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