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   uint64_t Vals[] = {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.getValueType()));
 760     Vals.push_back(A.getType()->getAddressSpace());
 761     Vals.push_back(VE.getValueID(A.getAliasee()));
 762     Vals.push_back(getEncodedLinkage(A));
 763     Vals.push_back(getEncodedVisibility(A));
 764     Vals.push_back(getEncodedDLLStorageClass(A));
 765     Vals.push_back(getEncodedThreadLocalMode(A));
 766     Vals.push_back(A.hasUnnamedAddr());
 767     unsigned AbbrevToUse = 0;
 768     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 769     Vals.clear();
 770   }
 771
 772   uint64_t VSTOffsetPlaceholder =
 773       WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
 774   return VSTOffsetPlaceholder;
 775 }
 776
 777 static uint64_t GetOptimizationFlags(const Value *V) {
 778   uint64_t Flags = 0;
 779
 780   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 781     if (OBO->hasNoSignedWrap())
 782       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 783     if (OBO->hasNoUnsignedWrap())
 784       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 785   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 786     if (PEO->isExact())
 787       Flags |= 1 << bitc::PEO_EXACT;
 788   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 789     if (FPMO->hasUnsafeAlgebra())
 790       Flags |= FastMathFlags::UnsafeAlgebra;
 791     if (FPMO->hasNoNaNs())
 792       Flags |= FastMathFlags::NoNaNs;
 793     if (FPMO->hasNoInfs())
 794       Flags |= FastMathFlags::NoInfs;
 795     if (FPMO->hasNoSignedZeros())
 796       Flags |= FastMathFlags::NoSignedZeros;
 797     if (FPMO->hasAllowReciprocal())
 798       Flags |= FastMathFlags::AllowReciprocal;
 799   }
 800
 801   return Flags;
 802 }
 803
 804 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 805                                  const ValueEnumerator &VE,
 806                                  BitstreamWriter &Stream,
 807                                  SmallVectorImpl<uint64_t> &Record) {
 808   // Mimic an MDNode with a value as one operand.
 809   Value *V = MD->getValue();
 810   Record.push_back(VE.getTypeID(V->getType()));
 811   Record.push_back(VE.getValueID(V));
 812   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 813   Record.clear();
 814 }
 815
 816 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 817                          BitstreamWriter &Stream,
 818                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 819   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 820     Metadata *MD = N->getOperand(i);
 821     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 822            "Unexpected function-local metadata");
 823     Record.push_back(VE.getMetadataOrNullID(MD));
 824   }
 825   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 826                                     : bitc::METADATA_NODE,
 827                     Record, Abbrev);
 828   Record.clear();
 829 }
 830
 831 static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
 832                             BitstreamWriter &Stream,
 833                             SmallVectorImpl<uint64_t> &Record,
 834                             unsigned Abbrev) {
 835   Record.push_back(N->isDistinct());
 836   Record.push_back(N->getLine());
 837   Record.push_back(N->getColumn());
 838   Record.push_back(VE.getMetadataID(N->getScope()));
 839   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 840
 841   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 842   Record.clear();
 843 }
 844
 845 static void WriteGenericDINode(const GenericDINode *N,
 846                                const ValueEnumerator &VE,
 847                                BitstreamWriter &Stream,
 848                                SmallVectorImpl<uint64_t> &Record,
 849                                unsigned Abbrev) {
 850   Record.push_back(N->isDistinct());
 851   Record.push_back(N->getTag());
 852   Record.push_back(0); // Per-tag version field; unused for now.
 853
 854   for (auto &I : N->operands())
 855     Record.push_back(VE.getMetadataOrNullID(I));
 856
 857   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 858   Record.clear();
 859 }
 860
 861 static uint64_t rotateSign(int64_t I) {
 862   uint64_t U = I;
 863   return I < 0 ? ~(U << 1) : U << 1;
 864 }
 865
 866 static void WriteDISubrange(const DISubrange *N, const ValueEnumerator &,
 867                             BitstreamWriter &Stream,
 868                             SmallVectorImpl<uint64_t> &Record,
 869                             unsigned Abbrev) {
 870   Record.push_back(N->isDistinct());
 871   Record.push_back(N->getCount());
 872   Record.push_back(rotateSign(N->getLowerBound()));
 873
 874   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 875   Record.clear();
 876 }
 877
 878 static void WriteDIEnumerator(const DIEnumerator *N, const ValueEnumerator &VE,
 879                               BitstreamWriter &Stream,
 880                               SmallVectorImpl<uint64_t> &Record,
 881                               unsigned Abbrev) {
 882   Record.push_back(N->isDistinct());
 883   Record.push_back(rotateSign(N->getValue()));
 884   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 885
 886   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 887   Record.clear();
 888 }
 889
 890 static void WriteDIBasicType(const DIBasicType *N, const ValueEnumerator &VE,
 891                              BitstreamWriter &Stream,
 892                              SmallVectorImpl<uint64_t> &Record,
 893                              unsigned Abbrev) {
 894   Record.push_back(N->isDistinct());
 895   Record.push_back(N->getTag());
 896   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 897   Record.push_back(N->getSizeInBits());
 898   Record.push_back(N->getAlignInBits());
 899   Record.push_back(N->getEncoding());
 900
 901   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 902   Record.clear();
 903 }
 904
 905 static void WriteDIDerivedType(const DIDerivedType *N,
 906                                const ValueEnumerator &VE,
 907                                BitstreamWriter &Stream,
 908                                SmallVectorImpl<uint64_t> &Record,
 909                                unsigned Abbrev) {
 910   Record.push_back(N->isDistinct());
 911   Record.push_back(N->getTag());
 912   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 913   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 914   Record.push_back(N->getLine());
 915   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 916   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 917   Record.push_back(N->getSizeInBits());
 918   Record.push_back(N->getAlignInBits());
 919   Record.push_back(N->getOffsetInBits());
 920   Record.push_back(N->getFlags());
 921   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 922
 923   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 924   Record.clear();
 925 }
 926
 927 static void WriteDICompositeType(const DICompositeType *N,
 928                                  const ValueEnumerator &VE,
 929                                  BitstreamWriter &Stream,
 930                                  SmallVectorImpl<uint64_t> &Record,
 931                                  unsigned Abbrev) {
 932   Record.push_back(N->isDistinct());
 933   Record.push_back(N->getTag());
 934   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 935   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 936   Record.push_back(N->getLine());
 937   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 938   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 939   Record.push_back(N->getSizeInBits());
 940   Record.push_back(N->getAlignInBits());
 941   Record.push_back(N->getOffsetInBits());
 942   Record.push_back(N->getFlags());
 943   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
 944   Record.push_back(N->getRuntimeLang());
 945   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 946   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
 947   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 948
 949   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 950   Record.clear();
 951 }
 952
 953 static void WriteDISubroutineType(const DISubroutineType *N,
 954                                   const ValueEnumerator &VE,
 955                                   BitstreamWriter &Stream,
 956                                   SmallVectorImpl<uint64_t> &Record,
 957                                   unsigned Abbrev) {
 958   Record.push_back(N->isDistinct());
 959   Record.push_back(N->getFlags());
 960   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
 961
 962   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 963   Record.clear();
 964 }
 965
 966 static void WriteDIFile(const DIFile *N, const ValueEnumerator &VE,
 967                         BitstreamWriter &Stream,
 968                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 969   Record.push_back(N->isDistinct());
 970   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 971   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 972
 973   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 974   Record.clear();
 975 }
 976
 977 static void WriteDICompileUnit(const DICompileUnit *N,
 978                                const ValueEnumerator &VE,
 979                                BitstreamWriter &Stream,
 980                                SmallVectorImpl<uint64_t> &Record,
 981                                unsigned Abbrev) {
 982   assert(N->isDistinct() && "Expected distinct compile units");
 983   Record.push_back(/* IsDistinct */ true);
 984   Record.push_back(N->getSourceLanguage());
 985   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 986   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 987   Record.push_back(N->isOptimized());
 988   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 989   Record.push_back(N->getRuntimeVersion());
 990   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 991   Record.push_back(N->getEmissionKind());
 992   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
 993   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
 994   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms().get()));
 995   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
 996   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
 997   Record.push_back(N->getDWOId());
 998
 999   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1000   Record.clear();
1001 }
1002
1003 static void WriteDISubprogram(const DISubprogram *N, const ValueEnumerator &VE,
1004                               BitstreamWriter &Stream,
1005                               SmallVectorImpl<uint64_t> &Record,
1006                               unsigned Abbrev) {
1007   Record.push_back(N->isDistinct());
1008   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1009   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1010   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1011   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1012   Record.push_back(N->getLine());
1013   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1014   Record.push_back(N->isLocalToUnit());
1015   Record.push_back(N->isDefinition());
1016   Record.push_back(N->getScopeLine());
1017   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1018   Record.push_back(N->getVirtuality());
1019   Record.push_back(N->getVirtualIndex());
1020   Record.push_back(N->getFlags());
1021   Record.push_back(N->isOptimized());
1022   Record.push_back(VE.getMetadataOrNullID(N->getRawFunction()));
1023   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1024   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1025   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1026
1027   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1028   Record.clear();
1029 }
1030
1031 static void WriteDILexicalBlock(const DILexicalBlock *N,
1032                                 const ValueEnumerator &VE,
1033                                 BitstreamWriter &Stream,
1034                                 SmallVectorImpl<uint64_t> &Record,
1035                                 unsigned Abbrev) {
1036   Record.push_back(N->isDistinct());
1037   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1038   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1039   Record.push_back(N->getLine());
1040   Record.push_back(N->getColumn());
1041
1042   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1043   Record.clear();
1044 }
1045
1046 static void WriteDILexicalBlockFile(const DILexicalBlockFile *N,
1047                                     const ValueEnumerator &VE,
1048                                     BitstreamWriter &Stream,
1049                                     SmallVectorImpl<uint64_t> &Record,
1050                                     unsigned Abbrev) {
1051   Record.push_back(N->isDistinct());
1052   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1053   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1054   Record.push_back(N->getDiscriminator());
1055
1056   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1057   Record.clear();
1058 }
1059
1060 static void WriteDINamespace(const DINamespace *N, const ValueEnumerator &VE,
1061                              BitstreamWriter &Stream,
1062                              SmallVectorImpl<uint64_t> &Record,
1063                              unsigned Abbrev) {
1064   Record.push_back(N->isDistinct());
1065   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1066   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1067   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1068   Record.push_back(N->getLine());
1069
1070   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1071   Record.clear();
1072 }
1073
1074 static void WriteDIModule(const DIModule *N, const ValueEnumerator &VE,
1075                           BitstreamWriter &Stream,
1076                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
1077   Record.push_back(N->isDistinct());
1078   for (auto &I : N->operands())
1079     Record.push_back(VE.getMetadataOrNullID(I));
1080
1081   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1082   Record.clear();
1083 }
1084
1085 static void WriteDITemplateTypeParameter(const DITemplateTypeParameter *N,
1086                                          const ValueEnumerator &VE,
1087                                          BitstreamWriter &Stream,
1088                                          SmallVectorImpl<uint64_t> &Record,
1089                                          unsigned Abbrev) {
1090   Record.push_back(N->isDistinct());
1091   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1092   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1093
1094   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1095   Record.clear();
1096 }
1097
1098 static void WriteDITemplateValueParameter(const DITemplateValueParameter *N,
1099                                           const ValueEnumerator &VE,
1100                                           BitstreamWriter &Stream,
1101                                           SmallVectorImpl<uint64_t> &Record,
1102                                           unsigned Abbrev) {
1103   Record.push_back(N->isDistinct());
1104   Record.push_back(N->getTag());
1105   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1106   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1107   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1108
1109   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1110   Record.clear();
1111 }
1112
1113 static void WriteDIGlobalVariable(const DIGlobalVariable *N,
1114                                   const ValueEnumerator &VE,
1115                                   BitstreamWriter &Stream,
1116                                   SmallVectorImpl<uint64_t> &Record,
1117                                   unsigned Abbrev) {
1118   Record.push_back(N->isDistinct());
1119   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1120   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1121   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1122   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1123   Record.push_back(N->getLine());
1124   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1125   Record.push_back(N->isLocalToUnit());
1126   Record.push_back(N->isDefinition());
1127   Record.push_back(VE.getMetadataOrNullID(N->getRawVariable()));
1128   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1129
1130   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1131   Record.clear();
1132 }
1133
1134 static void WriteDILocalVariable(const DILocalVariable *N,
1135                                  const ValueEnumerator &VE,
1136                                  BitstreamWriter &Stream,
1137                                  SmallVectorImpl<uint64_t> &Record,
1138                                  unsigned Abbrev) {
1139   Record.push_back(N->isDistinct());
1140   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1141   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1142   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1143   Record.push_back(N->getLine());
1144   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1145   Record.push_back(N->getArg());
1146   Record.push_back(N->getFlags());
1147
1148   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1149   Record.clear();
1150 }
1151
1152 static void WriteDIExpression(const DIExpression *N, const ValueEnumerator &,
1153                               BitstreamWriter &Stream,
1154                               SmallVectorImpl<uint64_t> &Record,
1155                               unsigned Abbrev) {
1156   Record.reserve(N->getElements().size() + 1);
1157
1158   Record.push_back(N->isDistinct());
1159   Record.append(N->elements_begin(), N->elements_end());
1160
1161   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1162   Record.clear();
1163 }
1164
1165 static void WriteDIObjCProperty(const DIObjCProperty *N,
1166                                 const ValueEnumerator &VE,
1167                                 BitstreamWriter &Stream,
1168                                 SmallVectorImpl<uint64_t> &Record,
1169                                 unsigned Abbrev) {
1170   Record.push_back(N->isDistinct());
1171   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1172   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1173   Record.push_back(N->getLine());
1174   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1175   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1176   Record.push_back(N->getAttributes());
1177   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1178
1179   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1180   Record.clear();
1181 }
1182
1183 static void WriteDIImportedEntity(const DIImportedEntity *N,
1184                                   const ValueEnumerator &VE,
1185                                   BitstreamWriter &Stream,
1186                                   SmallVectorImpl<uint64_t> &Record,
1187                                   unsigned Abbrev) {
1188   Record.push_back(N->isDistinct());
1189   Record.push_back(N->getTag());
1190   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1191   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1192   Record.push_back(N->getLine());
1193   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1194
1195   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1196   Record.clear();
1197 }
1198
1199 static void WriteModuleMetadata(const Module *M,
1200                                 const ValueEnumerator &VE,
1201                                 BitstreamWriter &Stream) {
1202   const auto &MDs = VE.getMDs();
1203   if (MDs.empty() && M->named_metadata_empty())
1204     return;
1205
1206   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1207
1208   unsigned MDSAbbrev = 0;
1209   if (VE.hasMDString()) {
1210     // Abbrev for METADATA_STRING.
1211     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1212     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1214     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1215     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1216   }
1217
1218   // Initialize MDNode abbreviations.
1219 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1220 #include "llvm/IR/Metadata.def"
1221
1222   if (VE.hasDILocation()) {
1223     // Abbrev for METADATA_LOCATION.
1224     //
1225     // Assume the column is usually under 128, and always output the inlined-at
1226     // location (it's never more expensive than building an array size 1).
1227     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1228     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1229     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1230     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1231     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1234     DILocationAbbrev = Stream.EmitAbbrev(Abbv);
1235   }
1236
1237   if (VE.hasGenericDINode()) {
1238     // Abbrev for METADATA_GENERIC_DEBUG.
1239     //
1240     // Assume the column is usually under 128, and always output the inlined-at
1241     // location (it's never more expensive than building an array size 1).
1242     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1243     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1250     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
1251   }
1252
1253   unsigned NameAbbrev = 0;
1254   if (!M->named_metadata_empty()) {
1255     // Abbrev for METADATA_NAME.
1256     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1257     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1260     NameAbbrev = Stream.EmitAbbrev(Abbv);
1261   }
1262
1263   SmallVector<uint64_t, 64> Record;
1264   for (const Metadata *MD : MDs) {
1265     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1266       assert(N->isResolved() && "Expected forward references to be resolved");
1267
1268       switch (N->getMetadataID()) {
1269       default:
1270         llvm_unreachable("Invalid MDNode subclass");
1271 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1272   case Metadata::CLASS##Kind:                                                  \
1273     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1274     continue;
1275 #include "llvm/IR/Metadata.def"
1276       }
1277     }
1278     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1279       WriteValueAsMetadata(MDC, VE, Stream, Record);
1280       continue;
1281     }
1282     const MDString *MDS = cast<MDString>(MD);
1283     // Code: [strchar x N]
1284     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1285
1286     // Emit the finished record.
1287     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1288     Record.clear();
1289   }
1290
1291   // Write named metadata.
1292   for (const NamedMDNode &NMD : M->named_metadata()) {
1293     // Write name.
1294     StringRef Str = NMD.getName();
1295     Record.append(Str.bytes_begin(), Str.bytes_end());
1296     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1297     Record.clear();
1298
1299     // Write named metadata operands.
1300     for (const MDNode *N : NMD.operands())
1301       Record.push_back(VE.getMetadataID(N));
1302     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1303     Record.clear();
1304   }
1305
1306   Stream.ExitBlock();
1307 }
1308
1309 static void WriteFunctionLocalMetadata(const Function &F,
1310                                        const ValueEnumerator &VE,
1311                                        BitstreamWriter &Stream) {
1312   bool StartedMetadataBlock = false;
1313   SmallVector<uint64_t, 64> Record;
1314   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1315       VE.getFunctionLocalMDs();
1316   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1317     assert(MDs[i] && "Expected valid function-local metadata");
1318     if (!StartedMetadataBlock) {
1319       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1320       StartedMetadataBlock = true;
1321     }
1322     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1323   }
1324
1325   if (StartedMetadataBlock)
1326     Stream.ExitBlock();
1327 }
1328
1329 static void WriteMetadataAttachment(const Function &F,
1330                                     const ValueEnumerator &VE,
1331                                     BitstreamWriter &Stream) {
1332   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1333
1334   SmallVector<uint64_t, 64> Record;
1335
1336   // Write metadata attachments
1337   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1338   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1339   F.getAllMetadata(MDs);
1340   if (!MDs.empty()) {
1341     for (const auto &I : MDs) {
1342       Record.push_back(I.first);
1343       Record.push_back(VE.getMetadataID(I.second));
1344     }
1345     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1346     Record.clear();
1347   }
1348
1349   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1350     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1351          I != E; ++I) {
1352       MDs.clear();
1353       I->getAllMetadataOtherThanDebugLoc(MDs);
1354
1355       // If no metadata, ignore instruction.
1356       if (MDs.empty()) continue;
1357
1358       Record.push_back(VE.getInstructionID(I));
1359
1360       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1361         Record.push_back(MDs[i].first);
1362         Record.push_back(VE.getMetadataID(MDs[i].second));
1363       }
1364       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1365       Record.clear();
1366     }
1367
1368   Stream.ExitBlock();
1369 }
1370
1371 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1372   SmallVector<uint64_t, 64> Record;
1373
1374   // Write metadata kinds
1375   // METADATA_KIND - [n x [id, name]]
1376   SmallVector<StringRef, 8> Names;
1377   M->getMDKindNames(Names);
1378
1379   if (Names.empty()) return;
1380
1381   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1382
1383   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1384     Record.push_back(MDKindID);
1385     StringRef KName = Names[MDKindID];
1386     Record.append(KName.begin(), KName.end());
1387
1388     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1389     Record.clear();
1390   }
1391
1392   Stream.ExitBlock();
1393 }
1394
1395 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1396   if ((int64_t)V >= 0)
1397     Vals.push_back(V << 1);
1398   else
1399     Vals.push_back((-V << 1) | 1);
1400 }
1401
1402 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1403                            const ValueEnumerator &VE,
1404                            BitstreamWriter &Stream, bool isGlobal) {
1405   if (FirstVal == LastVal) return;
1406
1407   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1408
1409   unsigned AggregateAbbrev = 0;
1410   unsigned String8Abbrev = 0;
1411   unsigned CString7Abbrev = 0;
1412   unsigned CString6Abbrev = 0;
1413   // If this is a constant pool for the module, emit module-specific abbrevs.
1414   if (isGlobal) {
1415     // Abbrev for CST_CODE_AGGREGATE.
1416     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1417     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1420     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1421
1422     // Abbrev for CST_CODE_STRING.
1423     Abbv = new BitCodeAbbrev();
1424     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1427     String8Abbrev = Stream.EmitAbbrev(Abbv);
1428     // Abbrev for CST_CODE_CSTRING.
1429     Abbv = new BitCodeAbbrev();
1430     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1433     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1434     // Abbrev for CST_CODE_CSTRING.
1435     Abbv = new BitCodeAbbrev();
1436     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1439     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1440   }
1441
1442   SmallVector<uint64_t, 64> Record;
1443
1444   const ValueEnumerator::ValueList &Vals = VE.getValues();
1445   Type *LastTy = nullptr;
1446   for (unsigned i = FirstVal; i != LastVal; ++i) {
1447     const Value *V = Vals[i].first;
1448     // If we need to switch types, do so now.
1449     if (V->getType() != LastTy) {
1450       LastTy = V->getType();
1451       Record.push_back(VE.getTypeID(LastTy));
1452       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1453                         CONSTANTS_SETTYPE_ABBREV);
1454       Record.clear();
1455     }
1456
1457     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1458       Record.push_back(unsigned(IA->hasSideEffects()) |
1459                        unsigned(IA->isAlignStack()) << 1 |
1460                        unsigned(IA->getDialect()&1) << 2);
1461
1462       // Add the asm string.
1463       const std::string &AsmStr = IA->getAsmString();
1464       Record.push_back(AsmStr.size());
1465       Record.append(AsmStr.begin(), AsmStr.end());
1466
1467       // Add the constraint string.
1468       const std::string &ConstraintStr = IA->getConstraintString();
1469       Record.push_back(ConstraintStr.size());
1470       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1471       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1472       Record.clear();
1473       continue;
1474     }
1475     const Constant *C = cast<Constant>(V);
1476     unsigned Code = -1U;
1477     unsigned AbbrevToUse = 0;
1478     if (C->isNullValue()) {
1479       Code = bitc::CST_CODE_NULL;
1480     } else if (isa<UndefValue>(C)) {
1481       Code = bitc::CST_CODE_UNDEF;
1482     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1483       if (IV->getBitWidth() <= 64) {
1484         uint64_t V = IV->getSExtValue();
1485         emitSignedInt64(Record, V);
1486         Code = bitc::CST_CODE_INTEGER;
1487         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1488       } else {                             // Wide integers, > 64 bits in size.
1489         // We have an arbitrary precision integer value to write whose
1490         // bit width is > 64. However, in canonical unsigned integer
1491         // format it is likely that the high bits are going to be zero.
1492         // So, we only write the number of active words.
1493         unsigned NWords = IV->getValue().getActiveWords();
1494         const uint64_t *RawWords = IV->getValue().getRawData();
1495         for (unsigned i = 0; i != NWords; ++i) {
1496           emitSignedInt64(Record, RawWords[i]);
1497         }
1498         Code = bitc::CST_CODE_WIDE_INTEGER;
1499       }
1500     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1501       Code = bitc::CST_CODE_FLOAT;
1502       Type *Ty = CFP->getType();
1503       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1504         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1505       } else if (Ty->isX86_FP80Ty()) {
1506         // api needed to prevent premature destruction
1507         // bits are not in the same order as a normal i80 APInt, compensate.
1508         APInt api = CFP->getValueAPF().bitcastToAPInt();
1509         const uint64_t *p = api.getRawData();
1510         Record.push_back((p[1] << 48) | (p[0] >> 16));
1511         Record.push_back(p[0] & 0xffffLL);
1512       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1513         APInt api = CFP->getValueAPF().bitcastToAPInt();
1514         const uint64_t *p = api.getRawData();
1515         Record.push_back(p[0]);
1516         Record.push_back(p[1]);
1517       } else {
1518         assert (0 && "Unknown FP type!");
1519       }
1520     } else if (isa<ConstantDataSequential>(C) &&
1521                cast<ConstantDataSequential>(C)->isString()) {
1522       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1523       // Emit constant strings specially.
1524       unsigned NumElts = Str->getNumElements();
1525       // If this is a null-terminated string, use the denser CSTRING encoding.
1526       if (Str->isCString()) {
1527         Code = bitc::CST_CODE_CSTRING;
1528         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1529       } else {
1530         Code = bitc::CST_CODE_STRING;
1531         AbbrevToUse = String8Abbrev;
1532       }
1533       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1534       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1535       for (unsigned i = 0; i != NumElts; ++i) {
1536         unsigned char V = Str->getElementAsInteger(i);
1537         Record.push_back(V);
1538         isCStr7 &= (V & 128) == 0;
1539         if (isCStrChar6)
1540           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1541       }
1542
1543       if (isCStrChar6)
1544         AbbrevToUse = CString6Abbrev;
1545       else if (isCStr7)
1546         AbbrevToUse = CString7Abbrev;
1547     } else if (const ConstantDataSequential *CDS =
1548                   dyn_cast<ConstantDataSequential>(C)) {
1549       Code = bitc::CST_CODE_DATA;
1550       Type *EltTy = CDS->getType()->getElementType();
1551       if (isa<IntegerType>(EltTy)) {
1552         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1553           Record.push_back(CDS->getElementAsInteger(i));
1554       } else if (EltTy->isFloatTy()) {
1555         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1556           union { float F; uint32_t I; };
1557           F = CDS->getElementAsFloat(i);
1558           Record.push_back(I);
1559         }
1560       } else {
1561         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1562         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1563           union { double F; uint64_t I; };
1564           F = CDS->getElementAsDouble(i);
1565           Record.push_back(I);
1566         }
1567       }
1568     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1569                isa<ConstantVector>(C)) {
1570       Code = bitc::CST_CODE_AGGREGATE;
1571       for (const Value *Op : C->operands())
1572         Record.push_back(VE.getValueID(Op));
1573       AbbrevToUse = AggregateAbbrev;
1574     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1575       switch (CE->getOpcode()) {
1576       default:
1577         if (Instruction::isCast(CE->getOpcode())) {
1578           Code = bitc::CST_CODE_CE_CAST;
1579           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1580           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1581           Record.push_back(VE.getValueID(C->getOperand(0)));
1582           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1583         } else {
1584           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1585           Code = bitc::CST_CODE_CE_BINOP;
1586           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1587           Record.push_back(VE.getValueID(C->getOperand(0)));
1588           Record.push_back(VE.getValueID(C->getOperand(1)));
1589           uint64_t Flags = GetOptimizationFlags(CE);
1590           if (Flags != 0)
1591             Record.push_back(Flags);
1592         }
1593         break;
1594       case Instruction::GetElementPtr: {
1595         Code = bitc::CST_CODE_CE_GEP;
1596         const auto *GO = cast<GEPOperator>(C);
1597         if (GO->isInBounds())
1598           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1599         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
1600         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1601           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1602           Record.push_back(VE.getValueID(C->getOperand(i)));
1603         }
1604         break;
1605       }
1606       case Instruction::Select:
1607         Code = bitc::CST_CODE_CE_SELECT;
1608         Record.push_back(VE.getValueID(C->getOperand(0)));
1609         Record.push_back(VE.getValueID(C->getOperand(1)));
1610         Record.push_back(VE.getValueID(C->getOperand(2)));
1611         break;
1612       case Instruction::ExtractElement:
1613         Code = bitc::CST_CODE_CE_EXTRACTELT;
1614         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1615         Record.push_back(VE.getValueID(C->getOperand(0)));
1616         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1617         Record.push_back(VE.getValueID(C->getOperand(1)));
1618         break;
1619       case Instruction::InsertElement:
1620         Code = bitc::CST_CODE_CE_INSERTELT;
1621         Record.push_back(VE.getValueID(C->getOperand(0)));
1622         Record.push_back(VE.getValueID(C->getOperand(1)));
1623         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1624         Record.push_back(VE.getValueID(C->getOperand(2)));
1625         break;
1626       case Instruction::ShuffleVector:
1627         // If the return type and argument types are the same, this is a
1628         // standard shufflevector instruction.  If the types are different,
1629         // then the shuffle is widening or truncating the input vectors, and
1630         // the argument type must also be encoded.
1631         if (C->getType() == C->getOperand(0)->getType()) {
1632           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1633         } else {
1634           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1635           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1636         }
1637         Record.push_back(VE.getValueID(C->getOperand(0)));
1638         Record.push_back(VE.getValueID(C->getOperand(1)));
1639         Record.push_back(VE.getValueID(C->getOperand(2)));
1640         break;
1641       case Instruction::ICmp:
1642       case Instruction::FCmp:
1643         Code = bitc::CST_CODE_CE_CMP;
1644         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1645         Record.push_back(VE.getValueID(C->getOperand(0)));
1646         Record.push_back(VE.getValueID(C->getOperand(1)));
1647         Record.push_back(CE->getPredicate());
1648         break;
1649       }
1650     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1651       Code = bitc::CST_CODE_BLOCKADDRESS;
1652       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1653       Record.push_back(VE.getValueID(BA->getFunction()));
1654       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1655     } else {
1656 #ifndef NDEBUG
1657       C->dump();
1658 #endif
1659       llvm_unreachable("Unknown constant!");
1660     }
1661     Stream.EmitRecord(Code, Record, AbbrevToUse);
1662     Record.clear();
1663   }
1664
1665   Stream.ExitBlock();
1666 }
1667
1668 static void WriteModuleConstants(const ValueEnumerator &VE,
1669                                  BitstreamWriter &Stream) {
1670   const ValueEnumerator::ValueList &Vals = VE.getValues();
1671
1672   // Find the first constant to emit, which is the first non-globalvalue value.
1673   // We know globalvalues have been emitted by WriteModuleInfo.
1674   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1675     if (!isa<GlobalValue>(Vals[i].first)) {
1676       WriteConstants(i, Vals.size(), VE, Stream, true);
1677       return;
1678     }
1679   }
1680 }
1681
1682 /// PushValueAndType - The file has to encode both the value and type id for
1683 /// many values, because we need to know what type to create for forward
1684 /// references.  However, most operands are not forward references, so this type
1685 /// field is not needed.
1686 ///
1687 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1688 /// instruction ID, then it is a forward reference, and it also includes the
1689 /// type ID.  The value ID that is written is encoded relative to the InstID.
1690 static bool PushValueAndType(const Value *V, unsigned InstID,
1691                              SmallVectorImpl<unsigned> &Vals,
1692                              ValueEnumerator &VE) {
1693   unsigned ValID = VE.getValueID(V);
1694   // Make encoding relative to the InstID.
1695   Vals.push_back(InstID - ValID);
1696   if (ValID >= InstID) {
1697     Vals.push_back(VE.getTypeID(V->getType()));
1698     return true;
1699   }
1700   return false;
1701 }
1702
1703 /// pushValue - Like PushValueAndType, but where the type of the value is
1704 /// omitted (perhaps it was already encoded in an earlier operand).
1705 static void pushValue(const Value *V, unsigned InstID,
1706                       SmallVectorImpl<unsigned> &Vals,
1707                       ValueEnumerator &VE) {
1708   unsigned ValID = VE.getValueID(V);
1709   Vals.push_back(InstID - ValID);
1710 }
1711
1712 static void pushValueSigned(const Value *V, unsigned InstID,
1713                             SmallVectorImpl<uint64_t> &Vals,
1714                             ValueEnumerator &VE) {
1715   unsigned ValID = VE.getValueID(V);
1716   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1717   emitSignedInt64(Vals, diff);
1718 }
1719
1720 /// WriteInstruction - Emit an instruction to the specified stream.
1721 static void WriteInstruction(const Instruction &I, unsigned InstID,
1722                              ValueEnumerator &VE, BitstreamWriter &Stream,
1723                              SmallVectorImpl<unsigned> &Vals) {
1724   unsigned Code = 0;
1725   unsigned AbbrevToUse = 0;
1726   VE.setInstructionID(&I);
1727   switch (I.getOpcode()) {
1728   default:
1729     if (Instruction::isCast(I.getOpcode())) {
1730       Code = bitc::FUNC_CODE_INST_CAST;
1731       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1732         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1733       Vals.push_back(VE.getTypeID(I.getType()));
1734       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1735     } else {
1736       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1737       Code = bitc::FUNC_CODE_INST_BINOP;
1738       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1739         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1740       pushValue(I.getOperand(1), InstID, Vals, VE);
1741       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1742       uint64_t Flags = GetOptimizationFlags(&I);
1743       if (Flags != 0) {
1744         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1745           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1746         Vals.push_back(Flags);
1747       }
1748     }
1749     break;
1750
1751   case Instruction::GetElementPtr: {
1752     Code = bitc::FUNC_CODE_INST_GEP;
1753     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
1754     auto &GEPInst = cast<GetElementPtrInst>(I);
1755     Vals.push_back(GEPInst.isInBounds());
1756     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
1757     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1758       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1759     break;
1760   }
1761   case Instruction::ExtractValue: {
1762     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1763     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1764     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1765     Vals.append(EVI->idx_begin(), EVI->idx_end());
1766     break;
1767   }
1768   case Instruction::InsertValue: {
1769     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1770     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1771     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1772     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1773     Vals.append(IVI->idx_begin(), IVI->idx_end());
1774     break;
1775   }
1776   case Instruction::Select:
1777     Code = bitc::FUNC_CODE_INST_VSELECT;
1778     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1779     pushValue(I.getOperand(2), InstID, Vals, VE);
1780     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1781     break;
1782   case Instruction::ExtractElement:
1783     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1784     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1785     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1786     break;
1787   case Instruction::InsertElement:
1788     Code = bitc::FUNC_CODE_INST_INSERTELT;
1789     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1790     pushValue(I.getOperand(1), InstID, Vals, VE);
1791     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1792     break;
1793   case Instruction::ShuffleVector:
1794     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1795     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1796     pushValue(I.getOperand(1), InstID, Vals, VE);
1797     pushValue(I.getOperand(2), InstID, Vals, VE);
1798     break;
1799   case Instruction::ICmp:
1800   case Instruction::FCmp: {
1801     // compare returning Int1Ty or vector of Int1Ty
1802     Code = bitc::FUNC_CODE_INST_CMP2;
1803     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1804     pushValue(I.getOperand(1), InstID, Vals, VE);
1805     Vals.push_back(cast<CmpInst>(I).getPredicate());
1806     uint64_t Flags = GetOptimizationFlags(&I);
1807     if (Flags != 0)
1808       Vals.push_back(Flags);
1809     break;
1810   }
1811
1812   case Instruction::Ret:
1813     {
1814       Code = bitc::FUNC_CODE_INST_RET;
1815       unsigned NumOperands = I.getNumOperands();
1816       if (NumOperands == 0)
1817         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1818       else if (NumOperands == 1) {
1819         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1820           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1821       } else {
1822         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1823           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1824       }
1825     }
1826     break;
1827   case Instruction::Br:
1828     {
1829       Code = bitc::FUNC_CODE_INST_BR;
1830       const BranchInst &II = cast<BranchInst>(I);
1831       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1832       if (II.isConditional()) {
1833         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1834         pushValue(II.getCondition(), InstID, Vals, VE);
1835       }
1836     }
1837     break;
1838   case Instruction::Switch:
1839     {
1840       Code = bitc::FUNC_CODE_INST_SWITCH;
1841       const SwitchInst &SI = cast<SwitchInst>(I);
1842       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1843       pushValue(SI.getCondition(), InstID, Vals, VE);
1844       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1845       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1846            i != e; ++i) {
1847         Vals.push_back(VE.getValueID(i.getCaseValue()));
1848         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1849       }
1850     }
1851     break;
1852   case Instruction::IndirectBr:
1853     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1854     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1855     // Encode the address operand as relative, but not the basic blocks.
1856     pushValue(I.getOperand(0), InstID, Vals, VE);
1857     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1858       Vals.push_back(VE.getValueID(I.getOperand(i)));
1859     break;
1860
1861   case Instruction::Invoke: {
1862     const InvokeInst *II = cast<InvokeInst>(&I);
1863     const Value *Callee = II->getCalledValue();
1864     FunctionType *FTy = II->getFunctionType();
1865     Code = bitc::FUNC_CODE_INST_INVOKE;
1866
1867     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1868     Vals.push_back(II->getCallingConv() | 1 << 13);
1869     Vals.push_back(VE.getValueID(II->getNormalDest()));
1870     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1871     Vals.push_back(VE.getTypeID(FTy));
1872     PushValueAndType(Callee, InstID, Vals, VE);
1873
1874     // Emit value #'s for the fixed parameters.
1875     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1876       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1877
1878     // Emit type/value pairs for varargs params.
1879     if (FTy->isVarArg()) {
1880       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1881            i != e; ++i)
1882         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1883     }
1884     break;
1885   }
1886   case Instruction::Resume:
1887     Code = bitc::FUNC_CODE_INST_RESUME;
1888     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1889     break;
1890   case Instruction::CleanupRet: {
1891     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
1892     const auto &CRI = cast<CleanupReturnInst>(I);
1893     pushValue(CRI.getCleanupPad(), InstID, Vals, VE);
1894     if (CRI.hasUnwindDest())
1895       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
1896     break;
1897   }
1898   case Instruction::CatchRet: {
1899     Code = bitc::FUNC_CODE_INST_CATCHRET;
1900     const auto &CRI = cast<CatchReturnInst>(I);
1901     pushValue(CRI.getCatchPad(), InstID, Vals, VE);
1902     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
1903     break;
1904   }
1905   case Instruction::CatchPad: {
1906     Code = bitc::FUNC_CODE_INST_CATCHPAD;
1907     const auto &CPI = cast<CatchPadInst>(I);
1908     Vals.push_back(VE.getValueID(CPI.getNormalDest()));
1909     Vals.push_back(VE.getValueID(CPI.getUnwindDest()));
1910     unsigned NumArgOperands = CPI.getNumArgOperands();
1911     Vals.push_back(NumArgOperands);
1912     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1913       PushValueAndType(CPI.getArgOperand(Op), InstID, Vals, VE);
1914     break;
1915   }
1916   case Instruction::TerminatePad: {
1917     Code = bitc::FUNC_CODE_INST_TERMINATEPAD;
1918     const auto &TPI = cast<TerminatePadInst>(I);
1919     Vals.push_back(TPI.hasUnwindDest());
1920     if (TPI.hasUnwindDest())
1921       Vals.push_back(VE.getValueID(TPI.getUnwindDest()));
1922     unsigned NumArgOperands = TPI.getNumArgOperands();
1923     Vals.push_back(NumArgOperands);
1924     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
1925       PushValueAndType(TPI.getArgOperand(Op), InstID, Vals, VE);
1926     break;
1927   }
1928   case Instruction::CleanupPad: {
1929     Code = bitc::FUNC_CODE_INST_CLEANUPPAD;
1930     const auto &CPI = cast<CleanupPadInst>(I);
1931     unsigned NumOperands = CPI.getNumOperands();
1932     Vals.push_back(NumOperands);
1933     for (unsigned Op = 0; Op != NumOperands; ++Op)
1934       PushValueAndType(CPI.getOperand(Op), InstID, Vals, VE);
1935     break;
1936   }
1937   case Instruction::CatchEndPad: {
1938     Code = bitc::FUNC_CODE_INST_CATCHENDPAD;
1939     const auto &CEPI = cast<CatchEndPadInst>(I);
1940     if (CEPI.hasUnwindDest())
1941       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
1942     break;
1943   }
1944   case Instruction::CleanupEndPad: {
1945     Code = bitc::FUNC_CODE_INST_CLEANUPENDPAD;
1946     const auto &CEPI = cast<CleanupEndPadInst>(I);
1947     pushValue(CEPI.getCleanupPad(), InstID, Vals, VE);
1948     if (CEPI.hasUnwindDest())
1949       Vals.push_back(VE.getValueID(CEPI.getUnwindDest()));
1950     break;
1951   }
1952   case Instruction::Unreachable:
1953     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1954     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1955     break;
1956
1957   case Instruction::PHI: {
1958     const PHINode &PN = cast<PHINode>(I);
1959     Code = bitc::FUNC_CODE_INST_PHI;
1960     // With the newer instruction encoding, forward references could give
1961     // negative valued IDs.  This is most common for PHIs, so we use
1962     // signed VBRs.
1963     SmallVector<uint64_t, 128> Vals64;
1964     Vals64.push_back(VE.getTypeID(PN.getType()));
1965     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1966       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1967       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1968     }
1969     // Emit a Vals64 vector and exit.
1970     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1971     Vals64.clear();
1972     return;
1973   }
1974
1975   case Instruction::LandingPad: {
1976     const LandingPadInst &LP = cast<LandingPadInst>(I);
1977     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1978     Vals.push_back(VE.getTypeID(LP.getType()));
1979     Vals.push_back(LP.isCleanup());
1980     Vals.push_back(LP.getNumClauses());
1981     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1982       if (LP.isCatch(I))
1983         Vals.push_back(LandingPadInst::Catch);
1984       else
1985         Vals.push_back(LandingPadInst::Filter);
1986       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1987     }
1988     break;
1989   }
1990
1991   case Instruction::Alloca: {
1992     Code = bitc::FUNC_CODE_INST_ALLOCA;
1993     const AllocaInst &AI = cast<AllocaInst>(I);
1994     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
1995     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1996     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1997     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1998     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1999            "not enough bits for maximum alignment");
2000     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2001     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2002     AlignRecord |= 1 << 6;
2003     // Reserve bit 7 for SwiftError flag.
2004     // AlignRecord |= AI.isSwiftError() << 7;
2005     Vals.push_back(AlignRecord);
2006     break;
2007   }
2008
2009   case Instruction::Load:
2010     if (cast<LoadInst>(I).isAtomic()) {
2011       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2012       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
2013     } else {
2014       Code = bitc::FUNC_CODE_INST_LOAD;
2015       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
2016         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2017     }
2018     Vals.push_back(VE.getTypeID(I.getType()));
2019     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2020     Vals.push_back(cast<LoadInst>(I).isVolatile());
2021     if (cast<LoadInst>(I).isAtomic()) {
2022       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2023       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2024     }
2025     break;
2026   case Instruction::Store:
2027     if (cast<StoreInst>(I).isAtomic())
2028       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2029     else
2030       Code = bitc::FUNC_CODE_INST_STORE;
2031     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
2032     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // valty + val
2033     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2034     Vals.push_back(cast<StoreInst>(I).isVolatile());
2035     if (cast<StoreInst>(I).isAtomic()) {
2036       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2037       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2038     }
2039     break;
2040   case Instruction::AtomicCmpXchg:
2041     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2042     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2043     PushValueAndType(I.getOperand(1), InstID, Vals, VE);         // cmp.
2044     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
2045     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2046     Vals.push_back(GetEncodedOrdering(
2047                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2048     Vals.push_back(GetEncodedSynchScope(
2049                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
2050     Vals.push_back(GetEncodedOrdering(
2051                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2052     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2053     break;
2054   case Instruction::AtomicRMW:
2055     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2056     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
2057     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
2058     Vals.push_back(GetEncodedRMWOperation(
2059                      cast<AtomicRMWInst>(I).getOperation()));
2060     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2061     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2062     Vals.push_back(GetEncodedSynchScope(
2063                      cast<AtomicRMWInst>(I).getSynchScope()));
2064     break;
2065   case Instruction::Fence:
2066     Code = bitc::FUNC_CODE_INST_FENCE;
2067     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2068     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2069     break;
2070   case Instruction::Call: {
2071     const CallInst &CI = cast<CallInst>(I);
2072     FunctionType *FTy = CI.getFunctionType();
2073
2074     Code = bitc::FUNC_CODE_INST_CALL;
2075
2076     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2077     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
2078                    unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
2079     Vals.push_back(VE.getTypeID(FTy));
2080     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
2081
2082     // Emit value #'s for the fixed parameters.
2083     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2084       // Check for labels (can happen with asm labels).
2085       if (FTy->getParamType(i)->isLabelTy())
2086         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2087       else
2088         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
2089     }
2090
2091     // Emit type/value pairs for varargs params.
2092     if (FTy->isVarArg()) {
2093       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2094            i != e; ++i)
2095         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
2096     }
2097     break;
2098   }
2099   case Instruction::VAArg:
2100     Code = bitc::FUNC_CODE_INST_VAARG;
2101     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2102     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
2103     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2104     break;
2105   }
2106
2107   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2108   Vals.clear();
2109 }
2110
2111 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
2112
2113 /// Determine the encoding to use for the given string name and length.
2114 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
2115   bool isChar6 = true;
2116   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
2117     if (isChar6)
2118       isChar6 = BitCodeAbbrevOp::isChar6(*C);
2119     if ((unsigned char)*C & 128)
2120       // don't bother scanning the rest.
2121       return SE_Fixed8;
2122   }
2123   if (isChar6)
2124     return SE_Char6;
2125   else
2126     return SE_Fixed7;
2127 }
2128
2129 /// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
2130 /// BitcodeStartBit and FunctionIndex are only passed for the module-level
2131 /// VST, where we are including a function bitcode index and need to
2132 /// backpatch the VST forward declaration record.
2133 static void WriteValueSymbolTable(
2134     const ValueSymbolTable &VST, const ValueEnumerator &VE,
2135     BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
2136     uint64_t BitcodeStartBit = 0,
2137     DenseMap<const Function *, uint64_t> *FunctionIndex = nullptr) {
2138   if (VST.empty()) {
2139     // WriteValueSymbolTableForwardDecl should have returned early as
2140     // well. Ensure this handling remains in sync by asserting that
2141     // the placeholder offset is not set.
2142     assert(VSTOffsetPlaceholder == 0);
2143     return;
2144   }
2145
2146   if (VSTOffsetPlaceholder > 0) {
2147     // Get the offset of the VST we are writing, and backpatch it into
2148     // the VST forward declaration record.
2149     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2150     // The BitcodeStartBit was the stream offset of the actual bitcode
2151     // (e.g. excluding any initial darwin header).
2152     VSTOffset -= BitcodeStartBit;
2153     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2154     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2155   }
2156
2157   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2158
2159   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2160   // records, which are not used in the per-function VSTs.
2161   unsigned FnEntry8BitAbbrev;
2162   unsigned FnEntry7BitAbbrev;
2163   unsigned FnEntry6BitAbbrev;
2164   if (VSTOffsetPlaceholder > 0) {
2165     // 8-bit fixed-width VST_FNENTRY function strings.
2166     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2167     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2170     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2171     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2172     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2173
2174     // 7-bit fixed width VST_FNENTRY function strings.
2175     Abbv = new BitCodeAbbrev();
2176     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2179     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2181     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2182
2183     // 6-bit char6 VST_FNENTRY function strings.
2184     Abbv = new BitCodeAbbrev();
2185     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // value id
2187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));  // funcoffset
2188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2190     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2191   }
2192
2193   // FIXME: Set up the abbrev, we know how many values there are!
2194   // FIXME: We know if the type names can use 7-bit ascii.
2195   SmallVector<unsigned, 64> NameVals;
2196
2197   for (const ValueName &Name : VST) {
2198     // Figure out the encoding to use for the name.
2199     StringEncoding Bits =
2200         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2201
2202     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2203     NameVals.push_back(VE.getValueID(Name.getValue()));
2204
2205     Function *F = dyn_cast<Function>(Name.getValue());
2206     if (!F) {
2207       // If value is an alias, need to get the aliased base object to
2208       // see if it is a function.
2209       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2210       if (GA && GA->getBaseObject())
2211         F = dyn_cast<Function>(GA->getBaseObject());
2212     }
2213
2214     // VST_ENTRY:   [valueid, namechar x N]
2215     // VST_FNENTRY: [valueid, funcoffset, namechar x N]
2216     // VST_BBENTRY: [bbid, namechar x N]
2217     unsigned Code;
2218     if (isa<BasicBlock>(Name.getValue())) {
2219       Code = bitc::VST_CODE_BBENTRY;
2220       if (Bits == SE_Char6)
2221         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2222     } else if (F && !F->isDeclaration()) {
2223       // Must be the module-level VST, where we pass in the Index and
2224       // have a VSTOffsetPlaceholder. The function-level VST should not
2225       // contain any Function symbols.
2226       assert(FunctionIndex);
2227       assert(VSTOffsetPlaceholder > 0);
2228
2229       // Save the word offset of the function (from the start of the
2230       // actual bitcode written to the stream).
2231       assert(FunctionIndex->count(F) == 1);
2232       uint64_t BitcodeIndex = (*FunctionIndex)[F] - BitcodeStartBit;
2233       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2234       NameVals.push_back(BitcodeIndex / 32);
2235
2236       Code = bitc::VST_CODE_FNENTRY;
2237       AbbrevToUse = FnEntry8BitAbbrev;
2238       if (Bits == SE_Char6)
2239         AbbrevToUse = FnEntry6BitAbbrev;
2240       else if (Bits == SE_Fixed7)
2241         AbbrevToUse = FnEntry7BitAbbrev;
2242     } else {
2243       Code = bitc::VST_CODE_ENTRY;
2244       if (Bits == SE_Char6)
2245         AbbrevToUse = VST_ENTRY_6_ABBREV;
2246       else if (Bits == SE_Fixed7)
2247         AbbrevToUse = VST_ENTRY_7_ABBREV;
2248     }
2249
2250     for (const char *P = Name.getKeyData(),
2251          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2252       NameVals.push_back((unsigned char)*P);
2253
2254     // Emit the finished record.
2255     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2256     NameVals.clear();
2257   }
2258   Stream.ExitBlock();
2259 }
2260
2261 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2262                          BitstreamWriter &Stream) {
2263   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2264   unsigned Code;
2265   if (isa<BasicBlock>(Order.V))
2266     Code = bitc::USELIST_CODE_BB;
2267   else
2268     Code = bitc::USELIST_CODE_DEFAULT;
2269
2270   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2271   Record.push_back(VE.getValueID(Order.V));
2272   Stream.EmitRecord(Code, Record);
2273 }
2274
2275 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2276                               BitstreamWriter &Stream) {
2277   assert(VE.shouldPreserveUseListOrder() &&
2278          "Expected to be preserving use-list order");
2279
2280   auto hasMore = [&]() {
2281     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2282   };
2283   if (!hasMore())
2284     // Nothing to do.
2285     return;
2286
2287   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2288   while (hasMore()) {
2289     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2290     VE.UseListOrders.pop_back();
2291   }
2292   Stream.ExitBlock();
2293 }
2294
2295 /// WriteFunction - Emit a function body to the module stream.
2296 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2297                           BitstreamWriter &Stream,
2298                           DenseMap<const Function *, uint64_t> &FunctionIndex) {
2299   // Save the bitcode index of the start of this function block for recording
2300   // in the VST.
2301   uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
2302   FunctionIndex[&F] = BitcodeIndex;
2303
2304   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2305   VE.incorporateFunction(F);
2306
2307   SmallVector<unsigned, 64> Vals;
2308
2309   // Emit the number of basic blocks, so the reader can create them ahead of
2310   // time.
2311   Vals.push_back(VE.getBasicBlocks().size());
2312   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2313   Vals.clear();
2314
2315   // If there are function-local constants, emit them now.
2316   unsigned CstStart, CstEnd;
2317   VE.getFunctionConstantRange(CstStart, CstEnd);
2318   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2319
2320   // If there is function-local metadata, emit it now.
2321   WriteFunctionLocalMetadata(F, VE, Stream);
2322
2323   // Keep a running idea of what the instruction ID is.
2324   unsigned InstID = CstEnd;
2325
2326   bool NeedsMetadataAttachment = F.hasMetadata();
2327
2328   DILocation *LastDL = nullptr;
2329
2330   // Finally, emit all the instructions, in order.
2331   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2332     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2333          I != E; ++I) {
2334       WriteInstruction(*I, InstID, VE, Stream, Vals);
2335
2336       if (!I->getType()->isVoidTy())
2337         ++InstID;
2338
2339       // If the instruction has metadata, write a metadata attachment later.
2340       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2341
2342       // If the instruction has a debug location, emit it.
2343       DILocation *DL = I->getDebugLoc();
2344       if (!DL)
2345         continue;
2346
2347       if (DL == LastDL) {
2348         // Just repeat the same debug loc as last time.
2349         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2350         continue;
2351       }
2352
2353       Vals.push_back(DL->getLine());
2354       Vals.push_back(DL->getColumn());
2355       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
2356       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
2357       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2358       Vals.clear();
2359
2360       LastDL = DL;
2361     }
2362
2363   // Emit names for all the instructions etc.
2364   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2365
2366   if (NeedsMetadataAttachment)
2367     WriteMetadataAttachment(F, VE, Stream);
2368   if (VE.shouldPreserveUseListOrder())
2369     WriteUseListBlock(&F, VE, Stream);
2370   VE.purgeFunction();
2371   Stream.ExitBlock();
2372 }
2373
2374 // Emit blockinfo, which defines the standard abbreviations etc.
2375 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2376   // We only want to emit block info records for blocks that have multiple
2377   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2378   // Other blocks can define their abbrevs inline.
2379   Stream.EnterBlockInfoBlock(2);
2380
2381   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2382     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2387     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2388                                    Abbv) != VST_ENTRY_8_ABBREV)
2389       llvm_unreachable("Unexpected abbrev ordering!");
2390   }
2391
2392   { // 7-bit fixed width VST_ENTRY strings.
2393     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2394     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2398     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2399                                    Abbv) != VST_ENTRY_7_ABBREV)
2400       llvm_unreachable("Unexpected abbrev ordering!");
2401   }
2402   { // 6-bit char6 VST_ENTRY strings.
2403     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2404     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2408     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2409                                    Abbv) != VST_ENTRY_6_ABBREV)
2410       llvm_unreachable("Unexpected abbrev ordering!");
2411   }
2412   { // 6-bit char6 VST_BBENTRY strings.
2413     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2414     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2418     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2419                                    Abbv) != VST_BBENTRY_6_ABBREV)
2420       llvm_unreachable("Unexpected abbrev ordering!");
2421   }
2422
2423
2424
2425   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2426     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2427     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2429                               VE.computeBitsRequiredForTypeIndicies()));
2430     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2431                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2432       llvm_unreachable("Unexpected abbrev ordering!");
2433   }
2434
2435   { // INTEGER abbrev for CONSTANTS_BLOCK.
2436     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2437     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2439     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2440                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2441       llvm_unreachable("Unexpected abbrev ordering!");
2442   }
2443
2444   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2445     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2446     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2449                               VE.computeBitsRequiredForTypeIndicies()));
2450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2451
2452     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2453                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2454       llvm_unreachable("Unexpected abbrev ordering!");
2455   }
2456   { // NULL abbrev for CONSTANTS_BLOCK.
2457     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2458     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2459     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2460                                    Abbv) != CONSTANTS_NULL_Abbrev)
2461       llvm_unreachable("Unexpected abbrev ordering!");
2462   }
2463
2464   // FIXME: This should only use space for first class types!
2465
2466   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2467     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2468     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
2471                               VE.computeBitsRequiredForTypeIndicies()));
2472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2474     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2475                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2476       llvm_unreachable("Unexpected abbrev ordering!");
2477   }
2478   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2479     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2480     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2484     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2485                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2486       llvm_unreachable("Unexpected abbrev ordering!");
2487   }
2488   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2489     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2490     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2495     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2496                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2497       llvm_unreachable("Unexpected abbrev ordering!");
2498   }
2499   { // INST_CAST abbrev for FUNCTION_BLOCK.
2500     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2501     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2504                               VE.computeBitsRequiredForTypeIndicies()));
2505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2506     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2507                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2508       llvm_unreachable("Unexpected abbrev ordering!");
2509   }
2510
2511   { // INST_RET abbrev for FUNCTION_BLOCK.
2512     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2513     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2514     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2515                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2516       llvm_unreachable("Unexpected abbrev ordering!");
2517   }
2518   { // INST_RET abbrev for FUNCTION_BLOCK.
2519     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2520     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2522     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2523                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2524       llvm_unreachable("Unexpected abbrev ordering!");
2525   }
2526   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2527     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2528     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2529     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2530                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2531       llvm_unreachable("Unexpected abbrev ordering!");
2532   }
2533   {
2534     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2535     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
2536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
2537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
2538                               Log2_32_Ceil(VE.getTypes().size() + 1)));
2539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2541     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
2542         FUNCTION_INST_GEP_ABBREV)
2543       llvm_unreachable("Unexpected abbrev ordering!");
2544   }
2545
2546   Stream.ExitBlock();
2547 }
2548
2549 /// WriteModule - Emit the specified module to the bitstream.
2550 static void WriteModule(const Module *M, BitstreamWriter &Stream,
2551                         bool ShouldPreserveUseListOrder,
2552                         uint64_t BitcodeStartBit) {
2553   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2554
2555   SmallVector<unsigned, 1> Vals;
2556   unsigned CurVersion = 1;
2557   Vals.push_back(CurVersion);
2558   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2559
2560   // Analyze the module, enumerating globals, functions, etc.
2561   ValueEnumerator VE(*M, ShouldPreserveUseListOrder);
2562
2563   // Emit blockinfo, which defines the standard abbreviations etc.
2564   WriteBlockInfo(VE, Stream);
2565
2566   // Emit information about attribute groups.
2567   WriteAttributeGroupTable(VE, Stream);
2568
2569   // Emit information about parameter attributes.
2570   WriteAttributeTable(VE, Stream);
2571
2572   // Emit information describing all of the types in the module.
2573   WriteTypeTable(VE, Stream);
2574
2575   writeComdats(VE, Stream);
2576
2577   // Emit top-level description of module, including target triple, inline asm,
2578   // descriptors for global variables, and function prototype info.
2579   uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
2580
2581   // Emit constants.
2582   WriteModuleConstants(VE, Stream);
2583
2584   // Emit metadata.
2585   WriteModuleMetadata(M, VE, Stream);
2586
2587   // Emit metadata.
2588   WriteModuleMetadataStore(M, Stream);
2589
2590   // Emit module-level use-lists.
2591   if (VE.shouldPreserveUseListOrder())
2592     WriteUseListBlock(nullptr, VE, Stream);
2593
2594   // Emit function bodies.
2595   DenseMap<const Function *, uint64_t> FunctionIndex;
2596   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2597     if (!F->isDeclaration())
2598       WriteFunction(*F, VE, Stream, FunctionIndex);
2599
2600   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
2601                         VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
2602
2603   Stream.ExitBlock();
2604 }
2605
2606 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2607 /// header and trailer to make it compatible with the system archiver.  To do
2608 /// this we emit the following header, and then emit a trailer that pads the
2609 /// file out to be a multiple of 16 bytes.
2610 ///
2611 /// struct bc_header {
2612 ///   uint32_t Magic;         // 0x0B17C0DE
2613 ///   uint32_t Version;       // Version, currently always 0.
2614 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2615 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2616 ///   uint32_t CPUType;       // CPU specifier.
2617 ///   ... potentially more later ...
2618 /// };
2619 enum {
2620   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2621   DarwinBCHeaderSize = 5*4
2622 };
2623
2624 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2625                                uint32_t &Position) {
2626   support::endian::write32le(&Buffer[Position], Value);
2627   Position += 4;
2628 }
2629
2630 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2631                                          const Triple &TT) {
2632   unsigned CPUType = ~0U;
2633
2634   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2635   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2636   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2637   // specific constants here because they are implicitly part of the Darwin ABI.
2638   enum {
2639     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2640     DARWIN_CPU_TYPE_X86        = 7,
2641     DARWIN_CPU_TYPE_ARM        = 12,
2642     DARWIN_CPU_TYPE_POWERPC    = 18
2643   };
2644
2645   Triple::ArchType Arch = TT.getArch();
2646   if (Arch == Triple::x86_64)
2647     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2648   else if (Arch == Triple::x86)
2649     CPUType = DARWIN_CPU_TYPE_X86;
2650   else if (Arch == Triple::ppc)
2651     CPUType = DARWIN_CPU_TYPE_POWERPC;
2652   else if (Arch == Triple::ppc64)
2653     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2654   else if (Arch == Triple::arm || Arch == Triple::thumb)
2655     CPUType = DARWIN_CPU_TYPE_ARM;
2656
2657   // Traditional Bitcode starts after header.
2658   assert(Buffer.size() >= DarwinBCHeaderSize &&
2659          "Expected header size to be reserved");
2660   unsigned BCOffset = DarwinBCHeaderSize;
2661   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2662
2663   // Write the magic and version.
2664   unsigned Position = 0;
2665   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2666   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2667   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2668   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2669   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2670
2671   // If the file is not a multiple of 16 bytes, insert dummy padding.
2672   while (Buffer.size() & 15)
2673     Buffer.push_back(0);
2674 }
2675
2676 /// WriteBitcodeToFile - Write the specified module to the specified output
2677 /// stream.
2678 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
2679                               bool ShouldPreserveUseListOrder) {
2680   SmallVector<char, 0> Buffer;
2681   Buffer.reserve(256*1024);
2682
2683   // If this is darwin or another generic macho target, reserve space for the
2684   // header.
2685   Triple TT(M->getTargetTriple());
2686   if (TT.isOSDarwin())
2687     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2688
2689   // Emit the module into the buffer.
2690   {
2691     BitstreamWriter Stream(Buffer);
2692     // Save the start bit of the actual bitcode, in case there is space
2693     // saved at the start for the darwin header above. The reader stream
2694     // will start at the bitcode, and we need the offset of the VST
2695     // to line up.
2696     uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
2697
2698     // Emit the file header.
2699     Stream.Emit((unsigned)'B', 8);
2700     Stream.Emit((unsigned)'C', 8);
2701     Stream.Emit(0x0, 4);
2702     Stream.Emit(0xC, 4);
2703     Stream.Emit(0xE, 4);
2704     Stream.Emit(0xD, 4);
2705
2706     // Emit the module.
2707     WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit);
2708   }
2709
2710   if (TT.isOSDarwin())
2711     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2712
2713   // Write the generated bitstream to "Out".
2714   Out.write((char*)&Buffer.front(), Buffer.size());
2715 }