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 };
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  78   }
  79 }
  80
  81 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  82   switch (Opcode) {
  83   default: llvm_unreachable("Unknown binary instruction!");
  84   case Instruction::Add:
  85   case Instruction::FAdd: return bitc::BINOP_ADD;
  86   case Instruction::Sub:
  87   case Instruction::FSub: return bitc::BINOP_SUB;
  88   case Instruction::Mul:
  89   case Instruction::FMul: return bitc::BINOP_MUL;
  90   case Instruction::UDiv: return bitc::BINOP_UDIV;
  91   case Instruction::FDiv:
  92   case Instruction::SDiv: return bitc::BINOP_SDIV;
  93   case Instruction::URem: return bitc::BINOP_UREM;
  94   case Instruction::FRem:
  95   case Instruction::SRem: return bitc::BINOP_SREM;
  96   case Instruction::Shl:  return bitc::BINOP_SHL;
  97   case Instruction::LShr: return bitc::BINOP_LSHR;
  98   case Instruction::AShr: return bitc::BINOP_ASHR;
  99   case Instruction::And:  return bitc::BINOP_AND;
 100   case Instruction::Or:   return bitc::BINOP_OR;
 101   case Instruction::Xor:  return bitc::BINOP_XOR;
 102   }
 103 }
 104
 105 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 106   switch (Op) {
 107   default: llvm_unreachable("Unknown RMW operation!");
 108   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 109   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 110   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 111   case AtomicRMWInst::And: return bitc::RMW_AND;
 112   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 113   case AtomicRMWInst::Or: return bitc::RMW_OR;
 114   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 115   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 116   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 117   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 118   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 119   }
 120 }
 121
 122 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 123   switch (Ordering) {
 124   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 125   case Unordered: return bitc::ORDERING_UNORDERED;
 126   case Monotonic: return bitc::ORDERING_MONOTONIC;
 127   case Acquire: return bitc::ORDERING_ACQUIRE;
 128   case Release: return bitc::ORDERING_RELEASE;
 129   case AcquireRelease: return bitc::ORDERING_ACQREL;
 130   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 131   }
 132   llvm_unreachable("Invalid ordering");
 133 }
 134
 135 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 136   switch (SynchScope) {
 137   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 138   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 139   }
 140   llvm_unreachable("Invalid synch scope");
 141 }
 142
 143 static void WriteStringRecord(unsigned Code, StringRef Str,
 144                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 145   SmallVector<unsigned, 64> Vals;
 146
 147   // Code: [strchar x N]
 148   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 149     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 150       AbbrevToUse = 0;
 151     Vals.push_back(Str[i]);
 152   }
 153
 154   // Emit the finished record.
 155   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 156 }
 157
 158 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 159   switch (Kind) {
 160   case Attribute::Alignment:
 161     return bitc::ATTR_KIND_ALIGNMENT;
 162   case Attribute::AlwaysInline:
 163     return bitc::ATTR_KIND_ALWAYS_INLINE;
 164   case Attribute::Builtin:
 165     return bitc::ATTR_KIND_BUILTIN;
 166   case Attribute::ByVal:
 167     return bitc::ATTR_KIND_BY_VAL;
 168   case Attribute::InAlloca:
 169     return bitc::ATTR_KIND_IN_ALLOCA;
 170   case Attribute::Cold:
 171     return bitc::ATTR_KIND_COLD;
 172   case Attribute::InlineHint:
 173     return bitc::ATTR_KIND_INLINE_HINT;
 174   case Attribute::InReg:
 175     return bitc::ATTR_KIND_IN_REG;
 176   case Attribute::JumpTable:
 177     return bitc::ATTR_KIND_JUMP_TABLE;
 178   case Attribute::MinSize:
 179     return bitc::ATTR_KIND_MIN_SIZE;
 180   case Attribute::Naked:
 181     return bitc::ATTR_KIND_NAKED;
 182   case Attribute::Nest:
 183     return bitc::ATTR_KIND_NEST;
 184   case Attribute::NoAlias:
 185     return bitc::ATTR_KIND_NO_ALIAS;
 186   case Attribute::NoBuiltin:
 187     return bitc::ATTR_KIND_NO_BUILTIN;
 188   case Attribute::NoCapture:
 189     return bitc::ATTR_KIND_NO_CAPTURE;
 190   case Attribute::NoDuplicate:
 191     return bitc::ATTR_KIND_NO_DUPLICATE;
 192   case Attribute::NoImplicitFloat:
 193     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 194   case Attribute::NoInline:
 195     return bitc::ATTR_KIND_NO_INLINE;
 196   case Attribute::NonLazyBind:
 197     return bitc::ATTR_KIND_NON_LAZY_BIND;
 198   case Attribute::NonNull:
 199     return bitc::ATTR_KIND_NON_NULL;
 200   case Attribute::Dereferenceable:
 201     return bitc::ATTR_KIND_DEREFERENCEABLE;
 202   case Attribute::NoRedZone:
 203     return bitc::ATTR_KIND_NO_RED_ZONE;
 204   case Attribute::NoReturn:
 205     return bitc::ATTR_KIND_NO_RETURN;
 206   case Attribute::NoUnwind:
 207     return bitc::ATTR_KIND_NO_UNWIND;
 208   case Attribute::OptimizeForSize:
 209     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 210   case Attribute::OptimizeNone:
 211     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 212   case Attribute::ReadNone:
 213     return bitc::ATTR_KIND_READ_NONE;
 214   case Attribute::ReadOnly:
 215     return bitc::ATTR_KIND_READ_ONLY;
 216   case Attribute::Returned:
 217     return bitc::ATTR_KIND_RETURNED;
 218   case Attribute::ReturnsTwice:
 219     return bitc::ATTR_KIND_RETURNS_TWICE;
 220   case Attribute::SExt:
 221     return bitc::ATTR_KIND_S_EXT;
 222   case Attribute::StackAlignment:
 223     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 224   case Attribute::StackProtect:
 225     return bitc::ATTR_KIND_STACK_PROTECT;
 226   case Attribute::StackProtectReq:
 227     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 228   case Attribute::StackProtectStrong:
 229     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 230   case Attribute::StructRet:
 231     return bitc::ATTR_KIND_STRUCT_RET;
 232   case Attribute::SanitizeAddress:
 233     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 234   case Attribute::SanitizeThread:
 235     return bitc::ATTR_KIND_SANITIZE_THREAD;
 236   case Attribute::SanitizeMemory:
 237     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 238   case Attribute::UWTable:
 239     return bitc::ATTR_KIND_UW_TABLE;
 240   case Attribute::ZExt:
 241     return bitc::ATTR_KIND_Z_EXT;
 242   case Attribute::EndAttrKinds:
 243     llvm_unreachable("Can not encode end-attribute kinds marker.");
 244   case Attribute::None:
 245     llvm_unreachable("Can not encode none-attribute.");
 246   }
 247
 248   llvm_unreachable("Trying to encode unknown attribute");
 249 }
 250
 251 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 252                                      BitstreamWriter &Stream) {
 253   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 254   if (AttrGrps.empty()) return;
 255
 256   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 257
 258   SmallVector<uint64_t, 64> Record;
 259   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 260     AttributeSet AS = AttrGrps[i];
 261     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 262       AttributeSet A = AS.getSlotAttributes(i);
 263
 264       Record.push_back(VE.getAttributeGroupID(A));
 265       Record.push_back(AS.getSlotIndex(i));
 266
 267       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 268            I != E; ++I) {
 269         Attribute Attr = *I;
 270         if (Attr.isEnumAttribute()) {
 271           Record.push_back(0);
 272           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 273         } else if (Attr.isIntAttribute()) {
 274           Record.push_back(1);
 275           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 276           Record.push_back(Attr.getValueAsInt());
 277         } else {
 278           StringRef Kind = Attr.getKindAsString();
 279           StringRef Val = Attr.getValueAsString();
 280
 281           Record.push_back(Val.empty() ? 3 : 4);
 282           Record.append(Kind.begin(), Kind.end());
 283           Record.push_back(0);
 284           if (!Val.empty()) {
 285             Record.append(Val.begin(), Val.end());
 286             Record.push_back(0);
 287           }
 288         }
 289       }
 290
 291       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 292       Record.clear();
 293     }
 294   }
 295
 296   Stream.ExitBlock();
 297 }
 298
 299 static void WriteAttributeTable(const ValueEnumerator &VE,
 300                                 BitstreamWriter &Stream) {
 301   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 302   if (Attrs.empty()) return;
 303
 304   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 305
 306   SmallVector<uint64_t, 64> Record;
 307   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 308     const AttributeSet &A = Attrs[i];
 309     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 310       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 311
 312     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 313     Record.clear();
 314   }
 315
 316   Stream.ExitBlock();
 317 }
 318
 319 /// WriteTypeTable - Write out the type table for a module.
 320 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 321   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 322
 323   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 324   SmallVector<uint64_t, 64> TypeVals;
 325
 326   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 327
 328   // Abbrev for TYPE_CODE_POINTER.
 329   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 330   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 332   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 333   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 334
 335   // Abbrev for TYPE_CODE_FUNCTION.
 336   Abbv = new BitCodeAbbrev();
 337   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 339   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 341
 342   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 343
 344   // Abbrev for TYPE_CODE_STRUCT_ANON.
 345   Abbv = new BitCodeAbbrev();
 346   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 348   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 349   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 350
 351   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 352
 353   // Abbrev for TYPE_CODE_STRUCT_NAME.
 354   Abbv = new BitCodeAbbrev();
 355   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 358   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 359
 360   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 361   Abbv = new BitCodeAbbrev();
 362   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 366
 367   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 368
 369   // Abbrev for TYPE_CODE_ARRAY.
 370   Abbv = new BitCodeAbbrev();
 371   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 373   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 374
 375   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 376
 377   // Emit an entry count so the reader can reserve space.
 378   TypeVals.push_back(TypeList.size());
 379   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 380   TypeVals.clear();
 381
 382   // Loop over all of the types, emitting each in turn.
 383   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 384     Type *T = TypeList[i];
 385     int AbbrevToUse = 0;
 386     unsigned Code = 0;
 387
 388     switch (T->getTypeID()) {
 389     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 390     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 391     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 392     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 393     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 394     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 395     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 396     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 397     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 398     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 399     case Type::IntegerTyID:
 400       // INTEGER: [width]
 401       Code = bitc::TYPE_CODE_INTEGER;
 402       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 403       break;
 404     case Type::PointerTyID: {
 405       PointerType *PTy = cast<PointerType>(T);
 406       // POINTER: [pointee type, address space]
 407       Code = bitc::TYPE_CODE_POINTER;
 408       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 409       unsigned AddressSpace = PTy->getAddressSpace();
 410       TypeVals.push_back(AddressSpace);
 411       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 412       break;
 413     }
 414     case Type::FunctionTyID: {
 415       FunctionType *FT = cast<FunctionType>(T);
 416       // FUNCTION: [isvararg, retty, paramty x N]
 417       Code = bitc::TYPE_CODE_FUNCTION;
 418       TypeVals.push_back(FT->isVarArg());
 419       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 420       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 421         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 422       AbbrevToUse = FunctionAbbrev;
 423       break;
 424     }
 425     case Type::StructTyID: {
 426       StructType *ST = cast<StructType>(T);
 427       // STRUCT: [ispacked, eltty x N]
 428       TypeVals.push_back(ST->isPacked());
 429       // Output all of the element types.
 430       for (StructType::element_iterator I = ST->element_begin(),
 431            E = ST->element_end(); I != E; ++I)
 432         TypeVals.push_back(VE.getTypeID(*I));
 433
 434       if (ST->isLiteral()) {
 435         Code = bitc::TYPE_CODE_STRUCT_ANON;
 436         AbbrevToUse = StructAnonAbbrev;
 437       } else {
 438         if (ST->isOpaque()) {
 439           Code = bitc::TYPE_CODE_OPAQUE;
 440         } else {
 441           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 442           AbbrevToUse = StructNamedAbbrev;
 443         }
 444
 445         // Emit the name if it is present.
 446         if (!ST->getName().empty())
 447           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 448                             StructNameAbbrev, Stream);
 449       }
 450       break;
 451     }
 452     case Type::ArrayTyID: {
 453       ArrayType *AT = cast<ArrayType>(T);
 454       // ARRAY: [numelts, eltty]
 455       Code = bitc::TYPE_CODE_ARRAY;
 456       TypeVals.push_back(AT->getNumElements());
 457       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 458       AbbrevToUse = ArrayAbbrev;
 459       break;
 460     }
 461     case Type::VectorTyID: {
 462       VectorType *VT = cast<VectorType>(T);
 463       // VECTOR [numelts, eltty]
 464       Code = bitc::TYPE_CODE_VECTOR;
 465       TypeVals.push_back(VT->getNumElements());
 466       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 467       break;
 468     }
 469     }
 470
 471     // Emit the finished record.
 472     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 473     TypeVals.clear();
 474   }
 475
 476   Stream.ExitBlock();
 477 }
 478
 479 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 480   switch (GV.getLinkage()) {
 481   case GlobalValue::ExternalLinkage:
 482     return 0;
 483   case GlobalValue::WeakAnyLinkage:
 484     return 16;
 485   case GlobalValue::AppendingLinkage:
 486     return 2;
 487   case GlobalValue::InternalLinkage:
 488     return 3;
 489   case GlobalValue::LinkOnceAnyLinkage:
 490     return 18;
 491   case GlobalValue::ExternalWeakLinkage:
 492     return 7;
 493   case GlobalValue::CommonLinkage:
 494     return 8;
 495   case GlobalValue::PrivateLinkage:
 496     return 9;
 497   case GlobalValue::WeakODRLinkage:
 498     return 17;
 499   case GlobalValue::LinkOnceODRLinkage:
 500     return 19;
 501   case GlobalValue::AvailableExternallyLinkage:
 502     return 12;
 503   }
 504   llvm_unreachable("Invalid linkage");
 505 }
 506
 507 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 508   switch (GV.getVisibility()) {
 509   case GlobalValue::DefaultVisibility:   return 0;
 510   case GlobalValue::HiddenVisibility:    return 1;
 511   case GlobalValue::ProtectedVisibility: return 2;
 512   }
 513   llvm_unreachable("Invalid visibility");
 514 }
 515
 516 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 517   switch (GV.getDLLStorageClass()) {
 518   case GlobalValue::DefaultStorageClass:   return 0;
 519   case GlobalValue::DLLImportStorageClass: return 1;
 520   case GlobalValue::DLLExportStorageClass: return 2;
 521   }
 522   llvm_unreachable("Invalid DLL storage class");
 523 }
 524
 525 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 526   switch (GV.getThreadLocalMode()) {
 527     case GlobalVariable::NotThreadLocal:         return 0;
 528     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 529     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 530     case GlobalVariable::InitialExecTLSModel:    return 3;
 531     case GlobalVariable::LocalExecTLSModel:      return 4;
 532   }
 533   llvm_unreachable("Invalid TLS model");
 534 }
 535
 536 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 537   switch (C.getSelectionKind()) {
 538   case Comdat::Any:
 539     return bitc::COMDAT_SELECTION_KIND_ANY;
 540   case Comdat::ExactMatch:
 541     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 542   case Comdat::Largest:
 543     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 544   case Comdat::NoDuplicates:
 545     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 546   case Comdat::SameSize:
 547     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 548   }
 549   llvm_unreachable("Invalid selection kind");
 550 }
 551
 552 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 553   SmallVector<uint16_t, 64> Vals;
 554   for (const Comdat *C : VE.getComdats()) {
 555     // COMDAT: [selection_kind, name]
 556     Vals.push_back(getEncodedComdatSelectionKind(*C));
 557     size_t Size = C->getName().size();
 558     assert(isUInt<16>(Size));
 559     Vals.push_back(Size);
 560     for (char Chr : C->getName())
 561       Vals.push_back((unsigned char)Chr);
 562     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 563     Vals.clear();
 564   }
 565 }
 566
 567 // Emit top-level description of module, including target triple, inline asm,
 568 // descriptors for global variables, and function prototype info.
 569 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 570                             BitstreamWriter &Stream) {
 571   // Emit various pieces of data attached to a module.
 572   if (!M->getTargetTriple().empty())
 573     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 574                       0/*TODO*/, Stream);
 575   const std::string &DL = M->getDataLayoutStr();
 576   if (!DL.empty())
 577     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 578   if (!M->getModuleInlineAsm().empty())
 579     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 580                       0/*TODO*/, Stream);
 581
 582   // Emit information about sections and GC, computing how many there are. Also
 583   // compute the maximum alignment value.
 584   std::map<std::string, unsigned> SectionMap;
 585   std::map<std::string, unsigned> GCMap;
 586   unsigned MaxAlignment = 0;
 587   unsigned MaxGlobalType = 0;
 588   for (const GlobalValue &GV : M->globals()) {
 589     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 590     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 591     if (GV.hasSection()) {
 592       // Give section names unique ID's.
 593       unsigned &Entry = SectionMap[GV.getSection()];
 594       if (!Entry) {
 595         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 596                           0/*TODO*/, Stream);
 597         Entry = SectionMap.size();
 598       }
 599     }
 600   }
 601   for (const Function &F : *M) {
 602     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 603     if (F.hasSection()) {
 604       // Give section names unique ID's.
 605       unsigned &Entry = SectionMap[F.getSection()];
 606       if (!Entry) {
 607         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 608                           0/*TODO*/, Stream);
 609         Entry = SectionMap.size();
 610       }
 611     }
 612     if (F.hasGC()) {
 613       // Same for GC names.
 614       unsigned &Entry = GCMap[F.getGC()];
 615       if (!Entry) {
 616         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 617                           0/*TODO*/, Stream);
 618         Entry = GCMap.size();
 619       }
 620     }
 621   }
 622
 623   // Emit abbrev for globals, now that we know # sections and max alignment.
 624   unsigned SimpleGVarAbbrev = 0;
 625   if (!M->global_empty()) {
 626     // Add an abbrev for common globals with no visibility or thread localness.
 627     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 628     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 629     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 630                               Log2_32_Ceil(MaxGlobalType+1)));
 631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5));      // Linkage.
 634     if (MaxAlignment == 0)                                      // Alignment.
 635       Abbv->Add(BitCodeAbbrevOp(0));
 636     else {
 637       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 638       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 639                                Log2_32_Ceil(MaxEncAlignment+1)));
 640     }
 641     if (SectionMap.empty())                                    // Section.
 642       Abbv->Add(BitCodeAbbrevOp(0));
 643     else
 644       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 645                                Log2_32_Ceil(SectionMap.size()+1)));
 646     // Don't bother emitting vis + thread local.
 647     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 648   }
 649
 650   // Emit the global variable information.
 651   SmallVector<unsigned, 64> Vals;
 652   for (const GlobalVariable &GV : M->globals()) {
 653     unsigned AbbrevToUse = 0;
 654
 655     // GLOBALVAR: [type, isconst, initid,
 656     //             linkage, alignment, section, visibility, threadlocal,
 657     //             unnamed_addr, externally_initialized, dllstorageclass,
 658     //             comdat]
 659     Vals.push_back(VE.getTypeID(GV.getType()));
 660     Vals.push_back(GV.isConstant());
 661     Vals.push_back(GV.isDeclaration() ? 0 :
 662                    (VE.getValueID(GV.getInitializer()) + 1));
 663     Vals.push_back(getEncodedLinkage(GV));
 664     Vals.push_back(Log2_32(GV.getAlignment())+1);
 665     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 666     if (GV.isThreadLocal() ||
 667         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 668         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 669         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 670         GV.hasComdat()) {
 671       Vals.push_back(getEncodedVisibility(GV));
 672       Vals.push_back(getEncodedThreadLocalMode(GV));
 673       Vals.push_back(GV.hasUnnamedAddr());
 674       Vals.push_back(GV.isExternallyInitialized());
 675       Vals.push_back(getEncodedDLLStorageClass(GV));
 676       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 677     } else {
 678       AbbrevToUse = SimpleGVarAbbrev;
 679     }
 680
 681     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 682     Vals.clear();
 683   }
 684
 685   // Emit the function proto information.
 686   for (const Function &F : *M) {
 687     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 688     //             section, visibility, gc, unnamed_addr, prologuedata,
 689     //             dllstorageclass, comdat, prefixdata]
 690     Vals.push_back(VE.getTypeID(F.getType()));
 691     Vals.push_back(F.getCallingConv());
 692     Vals.push_back(F.isDeclaration());
 693     Vals.push_back(getEncodedLinkage(F));
 694     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 695     Vals.push_back(Log2_32(F.getAlignment())+1);
 696     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 697     Vals.push_back(getEncodedVisibility(F));
 698     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 699     Vals.push_back(F.hasUnnamedAddr());
 700     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 701                                        : 0);
 702     Vals.push_back(getEncodedDLLStorageClass(F));
 703     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 704     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 705                                      : 0);
 706
 707     unsigned AbbrevToUse = 0;
 708     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 709     Vals.clear();
 710   }
 711
 712   // Emit the alias information.
 713   for (const GlobalAlias &A : M->aliases()) {
 714     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 715     Vals.push_back(VE.getTypeID(A.getType()));
 716     Vals.push_back(VE.getValueID(A.getAliasee()));
 717     Vals.push_back(getEncodedLinkage(A));
 718     Vals.push_back(getEncodedVisibility(A));
 719     Vals.push_back(getEncodedDLLStorageClass(A));
 720     Vals.push_back(getEncodedThreadLocalMode(A));
 721     Vals.push_back(A.hasUnnamedAddr());
 722     unsigned AbbrevToUse = 0;
 723     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 724     Vals.clear();
 725   }
 726 }
 727
 728 static uint64_t GetOptimizationFlags(const Value *V) {
 729   uint64_t Flags = 0;
 730
 731   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 732     if (OBO->hasNoSignedWrap())
 733       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 734     if (OBO->hasNoUnsignedWrap())
 735       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 736   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 737     if (PEO->isExact())
 738       Flags |= 1 << bitc::PEO_EXACT;
 739   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 740     if (FPMO->hasUnsafeAlgebra())
 741       Flags |= FastMathFlags::UnsafeAlgebra;
 742     if (FPMO->hasNoNaNs())
 743       Flags |= FastMathFlags::NoNaNs;
 744     if (FPMO->hasNoInfs())
 745       Flags |= FastMathFlags::NoInfs;
 746     if (FPMO->hasNoSignedZeros())
 747       Flags |= FastMathFlags::NoSignedZeros;
 748     if (FPMO->hasAllowReciprocal())
 749       Flags |= FastMathFlags::AllowReciprocal;
 750   }
 751
 752   return Flags;
 753 }
 754
 755 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 756                                  const ValueEnumerator &VE,
 757                                  BitstreamWriter &Stream,
 758                                  SmallVectorImpl<uint64_t> &Record) {
 759   // Mimic an MDNode with a value as one operand.
 760   Value *V = MD->getValue();
 761   Record.push_back(VE.getTypeID(V->getType()));
 762   Record.push_back(VE.getValueID(V));
 763   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 764   Record.clear();
 765 }
 766
 767 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 768                          BitstreamWriter &Stream,
 769                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 770   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 771     Metadata *MD = N->getOperand(i);
 772     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 773            "Unexpected function-local metadata");
 774     Record.push_back(VE.getMetadataOrNullID(MD));
 775   }
 776   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 777                                     : bitc::METADATA_NODE,
 778                     Record, Abbrev);
 779   Record.clear();
 780 }
 781
 782 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 783                             BitstreamWriter &Stream,
 784                             SmallVectorImpl<uint64_t> &Record,
 785                             unsigned Abbrev) {
 786   Record.push_back(N->isDistinct());
 787   Record.push_back(N->getLine());
 788   Record.push_back(N->getColumn());
 789   Record.push_back(VE.getMetadataID(N->getScope()));
 790   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 791
 792   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 793   Record.clear();
 794 }
 795
 796 static void WriteGenericDebugNode(const GenericDebugNode *N,
 797                                   const ValueEnumerator &VE,
 798                                   BitstreamWriter &Stream,
 799                                   SmallVectorImpl<uint64_t> &Record,
 800                                   unsigned Abbrev) {
 801   Record.push_back(N->isDistinct());
 802   Record.push_back(N->getTag());
 803   Record.push_back(0); // Per-tag version field; unused for now.
 804
 805   for (auto &I : N->operands())
 806     Record.push_back(VE.getMetadataOrNullID(I));
 807
 808   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 809   Record.clear();
 810 }
 811
 812 static uint64_t rotateSign(int64_t I) {
 813   uint64_t U = I;
 814   return I < 0 ? ~(U << 1) : U << 1;
 815 }
 816
 817 static void WriteMDSubrange(const MDSubrange *N, const ValueEnumerator &,
 818                             BitstreamWriter &Stream,
 819                             SmallVectorImpl<uint64_t> &Record,
 820                             unsigned Abbrev) {
 821   Record.push_back(N->isDistinct());
 822   Record.push_back(N->getCount());
 823   Record.push_back(rotateSign(N->getLo()));
 824
 825   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 826   Record.clear();
 827 }
 828
 829 static void WriteMDEnumerator(const MDEnumerator *N, const ValueEnumerator &VE,
 830                               BitstreamWriter &Stream,
 831                               SmallVectorImpl<uint64_t> &Record,
 832                               unsigned Abbrev) {
 833   Record.push_back(N->isDistinct());
 834   Record.push_back(rotateSign(N->getValue()));
 835   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 836
 837   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 838   Record.clear();
 839 }
 840
 841 static void WriteMDBasicType(const MDBasicType *N, const ValueEnumerator &VE,
 842                              BitstreamWriter &Stream,
 843                              SmallVectorImpl<uint64_t> &Record,
 844                              unsigned Abbrev) {
 845   Record.push_back(N->isDistinct());
 846   Record.push_back(N->getTag());
 847   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 848   Record.push_back(N->getSizeInBits());
 849   Record.push_back(N->getAlignInBits());
 850   Record.push_back(N->getEncoding());
 851
 852   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 853   Record.clear();
 854 }
 855
 856 static void WriteMDDerivedType(const MDDerivedType *, const ValueEnumerator &,
 857                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 858                                unsigned) {
 859   llvm_unreachable("write not implemented");
 860 }
 861 static void WriteMDCompositeType(const MDCompositeType *,
 862                                  const ValueEnumerator &, BitstreamWriter &,
 863                                  SmallVectorImpl<uint64_t> &, unsigned) {
 864   llvm_unreachable("write not implemented");
 865 }
 866 static void WriteMDSubroutineType(const MDSubroutineType *,
 867                                   const ValueEnumerator &, BitstreamWriter &,
 868                                   SmallVectorImpl<uint64_t> &, unsigned) {
 869   llvm_unreachable("write not implemented");
 870 }
 871
 872 static void WriteMDFile(const MDFile *N, const ValueEnumerator &VE,
 873                         BitstreamWriter &Stream,
 874                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 875   Record.push_back(N->isDistinct());
 876   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 877   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 878
 879   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 880   Record.clear();
 881 }
 882
 883 static void WriteMDCompileUnit(const MDCompileUnit *, const ValueEnumerator &,
 884                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 885                                unsigned) {
 886   llvm_unreachable("write not implemented");
 887 }
 888 static void WriteMDSubprogram(const MDSubprogram *, const ValueEnumerator &,
 889                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 890                               unsigned) {
 891   llvm_unreachable("write not implemented");
 892 }
 893 static void WriteMDLexicalBlock(const MDLexicalBlock *, const ValueEnumerator &,
 894                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 895                                 unsigned) {
 896   llvm_unreachable("write not implemented");
 897 }
 898 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *,
 899                                     const ValueEnumerator &, BitstreamWriter &,
 900                                     SmallVectorImpl<uint64_t> &, unsigned) {
 901   llvm_unreachable("write not implemented");
 902 }
 903 static void WriteMDNamespace(const MDNamespace *, const ValueEnumerator &,
 904                              BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 905                              unsigned) {
 906   llvm_unreachable("write not implemented");
 907 }
 908 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *,
 909                                          const ValueEnumerator &,
 910                                          BitstreamWriter &,
 911                                          SmallVectorImpl<uint64_t> &,
 912                                          unsigned) {
 913   llvm_unreachable("write not implemented");
 914 }
 915 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *,
 916                                           const ValueEnumerator &,
 917                                           BitstreamWriter &,
 918                                           SmallVectorImpl<uint64_t> &,
 919                                           unsigned) {
 920   llvm_unreachable("write not implemented");
 921 }
 922 static void WriteMDGlobalVariable(const MDGlobalVariable *,
 923                                   const ValueEnumerator &, BitstreamWriter &,
 924                                   SmallVectorImpl<uint64_t> &, unsigned) {
 925   llvm_unreachable("write not implemented");
 926 }
 927 static void WriteMDLocalVariable(const MDLocalVariable *,
 928                                  const ValueEnumerator &, BitstreamWriter &,
 929                                  SmallVectorImpl<uint64_t> &, unsigned) {
 930   llvm_unreachable("write not implemented");
 931 }
 932 static void WriteMDExpression(const MDExpression *, const ValueEnumerator &,
 933                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 934                               unsigned) {
 935   llvm_unreachable("write not implemented");
 936 }
 937 static void WriteMDObjCProperty(const MDObjCProperty *, const ValueEnumerator &,
 938                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 939                                 unsigned) {
 940   llvm_unreachable("write not implemented");
 941 }
 942 static void WriteMDImportedEntity(const MDImportedEntity *,
 943                                   const ValueEnumerator &, BitstreamWriter &,
 944                                   SmallVectorImpl<uint64_t> &, unsigned) {
 945   llvm_unreachable("write not implemented");
 946 }
 947
 948 static void WriteModuleMetadata(const Module *M,
 949                                 const ValueEnumerator &VE,
 950                                 BitstreamWriter &Stream) {
 951   const auto &MDs = VE.getMDs();
 952   if (MDs.empty() && M->named_metadata_empty())
 953     return;
 954
 955   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 956
 957   unsigned MDSAbbrev = 0;
 958   if (VE.hasMDString()) {
 959     // Abbrev for METADATA_STRING.
 960     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 961     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 962     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 963     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 964     MDSAbbrev = Stream.EmitAbbrev(Abbv);
 965   }
 966
 967   // Initialize MDNode abbreviations.
 968 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
 969 #include "llvm/IR/Metadata.def"
 970
 971   if (VE.hasMDLocation()) {
 972     // Abbrev for METADATA_LOCATION.
 973     //
 974     // Assume the column is usually under 128, and always output the inlined-at
 975     // location (it's never more expensive than building an array size 1).
 976     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 977     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
 978     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 979     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 980     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 981     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 982     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 983     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
 984   }
 985
 986   if (VE.hasGenericDebugNode()) {
 987     // Abbrev for METADATA_GENERIC_DEBUG.
 988     //
 989     // Assume the column is usually under 128, and always output the inlined-at
 990     // location (it's never more expensive than building an array size 1).
 991     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 992     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
 993     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 994     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 995     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 996     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 997     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 998     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 999     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1000   }
1001
1002   unsigned NameAbbrev = 0;
1003   if (!M->named_metadata_empty()) {
1004     // Abbrev for METADATA_NAME.
1005     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1006     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1007     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1008     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1009     NameAbbrev = Stream.EmitAbbrev(Abbv);
1010   }
1011
1012   SmallVector<uint64_t, 64> Record;
1013   for (const Metadata *MD : MDs) {
1014     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1015       switch (N->getMetadataID()) {
1016       default:
1017         llvm_unreachable("Invalid MDNode subclass");
1018 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1019   case Metadata::CLASS##Kind:                                                  \
1020     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1021     continue;
1022 #include "llvm/IR/Metadata.def"
1023       }
1024     }
1025     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1026       WriteValueAsMetadata(MDC, VE, Stream, Record);
1027       continue;
1028     }
1029     const MDString *MDS = cast<MDString>(MD);
1030     // Code: [strchar x N]
1031     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1032
1033     // Emit the finished record.
1034     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1035     Record.clear();
1036   }
1037
1038   // Write named metadata.
1039   for (const NamedMDNode &NMD : M->named_metadata()) {
1040     // Write name.
1041     StringRef Str = NMD.getName();
1042     Record.append(Str.bytes_begin(), Str.bytes_end());
1043     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1044     Record.clear();
1045
1046     // Write named metadata operands.
1047     for (const MDNode *N : NMD.operands())
1048       Record.push_back(VE.getMetadataID(N));
1049     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1050     Record.clear();
1051   }
1052
1053   Stream.ExitBlock();
1054 }
1055
1056 static void WriteFunctionLocalMetadata(const Function &F,
1057                                        const ValueEnumerator &VE,
1058                                        BitstreamWriter &Stream) {
1059   bool StartedMetadataBlock = false;
1060   SmallVector<uint64_t, 64> Record;
1061   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1062       VE.getFunctionLocalMDs();
1063   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1064     assert(MDs[i] && "Expected valid function-local metadata");
1065     if (!StartedMetadataBlock) {
1066       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1067       StartedMetadataBlock = true;
1068     }
1069     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1070   }
1071
1072   if (StartedMetadataBlock)
1073     Stream.ExitBlock();
1074 }
1075
1076 static void WriteMetadataAttachment(const Function &F,
1077                                     const ValueEnumerator &VE,
1078                                     BitstreamWriter &Stream) {
1079   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1080
1081   SmallVector<uint64_t, 64> Record;
1082
1083   // Write metadata attachments
1084   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1085   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1086
1087   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1088     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1089          I != E; ++I) {
1090       MDs.clear();
1091       I->getAllMetadataOtherThanDebugLoc(MDs);
1092
1093       // If no metadata, ignore instruction.
1094       if (MDs.empty()) continue;
1095
1096       Record.push_back(VE.getInstructionID(I));
1097
1098       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1099         Record.push_back(MDs[i].first);
1100         Record.push_back(VE.getMetadataID(MDs[i].second));
1101       }
1102       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1103       Record.clear();
1104     }
1105
1106   Stream.ExitBlock();
1107 }
1108
1109 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1110   SmallVector<uint64_t, 64> Record;
1111
1112   // Write metadata kinds
1113   // METADATA_KIND - [n x [id, name]]
1114   SmallVector<StringRef, 8> Names;
1115   M->getMDKindNames(Names);
1116
1117   if (Names.empty()) return;
1118
1119   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1120
1121   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1122     Record.push_back(MDKindID);
1123     StringRef KName = Names[MDKindID];
1124     Record.append(KName.begin(), KName.end());
1125
1126     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1127     Record.clear();
1128   }
1129
1130   Stream.ExitBlock();
1131 }
1132
1133 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1134   if ((int64_t)V >= 0)
1135     Vals.push_back(V << 1);
1136   else
1137     Vals.push_back((-V << 1) | 1);
1138 }
1139
1140 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1141                            const ValueEnumerator &VE,
1142                            BitstreamWriter &Stream, bool isGlobal) {
1143   if (FirstVal == LastVal) return;
1144
1145   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1146
1147   unsigned AggregateAbbrev = 0;
1148   unsigned String8Abbrev = 0;
1149   unsigned CString7Abbrev = 0;
1150   unsigned CString6Abbrev = 0;
1151   // If this is a constant pool for the module, emit module-specific abbrevs.
1152   if (isGlobal) {
1153     // Abbrev for CST_CODE_AGGREGATE.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1158     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1159
1160     // Abbrev for CST_CODE_STRING.
1161     Abbv = new BitCodeAbbrev();
1162     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1165     String8Abbrev = Stream.EmitAbbrev(Abbv);
1166     // Abbrev for CST_CODE_CSTRING.
1167     Abbv = new BitCodeAbbrev();
1168     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1170     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1171     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1172     // Abbrev for CST_CODE_CSTRING.
1173     Abbv = new BitCodeAbbrev();
1174     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1177     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1178   }
1179
1180   SmallVector<uint64_t, 64> Record;
1181
1182   const ValueEnumerator::ValueList &Vals = VE.getValues();
1183   Type *LastTy = nullptr;
1184   for (unsigned i = FirstVal; i != LastVal; ++i) {
1185     const Value *V = Vals[i].first;
1186     // If we need to switch types, do so now.
1187     if (V->getType() != LastTy) {
1188       LastTy = V->getType();
1189       Record.push_back(VE.getTypeID(LastTy));
1190       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1191                         CONSTANTS_SETTYPE_ABBREV);
1192       Record.clear();
1193     }
1194
1195     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1196       Record.push_back(unsigned(IA->hasSideEffects()) |
1197                        unsigned(IA->isAlignStack()) << 1 |
1198                        unsigned(IA->getDialect()&1) << 2);
1199
1200       // Add the asm string.
1201       const std::string &AsmStr = IA->getAsmString();
1202       Record.push_back(AsmStr.size());
1203       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1204         Record.push_back(AsmStr[i]);
1205
1206       // Add the constraint string.
1207       const std::string &ConstraintStr = IA->getConstraintString();
1208       Record.push_back(ConstraintStr.size());
1209       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1210         Record.push_back(ConstraintStr[i]);
1211       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1212       Record.clear();
1213       continue;
1214     }
1215     const Constant *C = cast<Constant>(V);
1216     unsigned Code = -1U;
1217     unsigned AbbrevToUse = 0;
1218     if (C->isNullValue()) {
1219       Code = bitc::CST_CODE_NULL;
1220     } else if (isa<UndefValue>(C)) {
1221       Code = bitc::CST_CODE_UNDEF;
1222     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1223       if (IV->getBitWidth() <= 64) {
1224         uint64_t V = IV->getSExtValue();
1225         emitSignedInt64(Record, V);
1226         Code = bitc::CST_CODE_INTEGER;
1227         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1228       } else {                             // Wide integers, > 64 bits in size.
1229         // We have an arbitrary precision integer value to write whose
1230         // bit width is > 64. However, in canonical unsigned integer
1231         // format it is likely that the high bits are going to be zero.
1232         // So, we only write the number of active words.
1233         unsigned NWords = IV->getValue().getActiveWords();
1234         const uint64_t *RawWords = IV->getValue().getRawData();
1235         for (unsigned i = 0; i != NWords; ++i) {
1236           emitSignedInt64(Record, RawWords[i]);
1237         }
1238         Code = bitc::CST_CODE_WIDE_INTEGER;
1239       }
1240     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1241       Code = bitc::CST_CODE_FLOAT;
1242       Type *Ty = CFP->getType();
1243       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1244         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1245       } else if (Ty->isX86_FP80Ty()) {
1246         // api needed to prevent premature destruction
1247         // bits are not in the same order as a normal i80 APInt, compensate.
1248         APInt api = CFP->getValueAPF().bitcastToAPInt();
1249         const uint64_t *p = api.getRawData();
1250         Record.push_back((p[1] << 48) | (p[0] >> 16));
1251         Record.push_back(p[0] & 0xffffLL);
1252       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1253         APInt api = CFP->getValueAPF().bitcastToAPInt();
1254         const uint64_t *p = api.getRawData();
1255         Record.push_back(p[0]);
1256         Record.push_back(p[1]);
1257       } else {
1258         assert (0 && "Unknown FP type!");
1259       }
1260     } else if (isa<ConstantDataSequential>(C) &&
1261                cast<ConstantDataSequential>(C)->isString()) {
1262       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1263       // Emit constant strings specially.
1264       unsigned NumElts = Str->getNumElements();
1265       // If this is a null-terminated string, use the denser CSTRING encoding.
1266       if (Str->isCString()) {
1267         Code = bitc::CST_CODE_CSTRING;
1268         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1269       } else {
1270         Code = bitc::CST_CODE_STRING;
1271         AbbrevToUse = String8Abbrev;
1272       }
1273       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1274       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1275       for (unsigned i = 0; i != NumElts; ++i) {
1276         unsigned char V = Str->getElementAsInteger(i);
1277         Record.push_back(V);
1278         isCStr7 &= (V & 128) == 0;
1279         if (isCStrChar6)
1280           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1281       }
1282
1283       if (isCStrChar6)
1284         AbbrevToUse = CString6Abbrev;
1285       else if (isCStr7)
1286         AbbrevToUse = CString7Abbrev;
1287     } else if (const ConstantDataSequential *CDS =
1288                   dyn_cast<ConstantDataSequential>(C)) {
1289       Code = bitc::CST_CODE_DATA;
1290       Type *EltTy = CDS->getType()->getElementType();
1291       if (isa<IntegerType>(EltTy)) {
1292         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1293           Record.push_back(CDS->getElementAsInteger(i));
1294       } else if (EltTy->isFloatTy()) {
1295         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1296           union { float F; uint32_t I; };
1297           F = CDS->getElementAsFloat(i);
1298           Record.push_back(I);
1299         }
1300       } else {
1301         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1302         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1303           union { double F; uint64_t I; };
1304           F = CDS->getElementAsDouble(i);
1305           Record.push_back(I);
1306         }
1307       }
1308     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1309                isa<ConstantVector>(C)) {
1310       Code = bitc::CST_CODE_AGGREGATE;
1311       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1312         Record.push_back(VE.getValueID(C->getOperand(i)));
1313       AbbrevToUse = AggregateAbbrev;
1314     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1315       switch (CE->getOpcode()) {
1316       default:
1317         if (Instruction::isCast(CE->getOpcode())) {
1318           Code = bitc::CST_CODE_CE_CAST;
1319           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1320           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1321           Record.push_back(VE.getValueID(C->getOperand(0)));
1322           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1323         } else {
1324           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1325           Code = bitc::CST_CODE_CE_BINOP;
1326           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1327           Record.push_back(VE.getValueID(C->getOperand(0)));
1328           Record.push_back(VE.getValueID(C->getOperand(1)));
1329           uint64_t Flags = GetOptimizationFlags(CE);
1330           if (Flags != 0)
1331             Record.push_back(Flags);
1332         }
1333         break;
1334       case Instruction::GetElementPtr:
1335         Code = bitc::CST_CODE_CE_GEP;
1336         if (cast<GEPOperator>(C)->isInBounds())
1337           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1338         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1339           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1340           Record.push_back(VE.getValueID(C->getOperand(i)));
1341         }
1342         break;
1343       case Instruction::Select:
1344         Code = bitc::CST_CODE_CE_SELECT;
1345         Record.push_back(VE.getValueID(C->getOperand(0)));
1346         Record.push_back(VE.getValueID(C->getOperand(1)));
1347         Record.push_back(VE.getValueID(C->getOperand(2)));
1348         break;
1349       case Instruction::ExtractElement:
1350         Code = bitc::CST_CODE_CE_EXTRACTELT;
1351         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1352         Record.push_back(VE.getValueID(C->getOperand(0)));
1353         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1354         Record.push_back(VE.getValueID(C->getOperand(1)));
1355         break;
1356       case Instruction::InsertElement:
1357         Code = bitc::CST_CODE_CE_INSERTELT;
1358         Record.push_back(VE.getValueID(C->getOperand(0)));
1359         Record.push_back(VE.getValueID(C->getOperand(1)));
1360         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1361         Record.push_back(VE.getValueID(C->getOperand(2)));
1362         break;
1363       case Instruction::ShuffleVector:
1364         // If the return type and argument types are the same, this is a
1365         // standard shufflevector instruction.  If the types are different,
1366         // then the shuffle is widening or truncating the input vectors, and
1367         // the argument type must also be encoded.
1368         if (C->getType() == C->getOperand(0)->getType()) {
1369           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1370         } else {
1371           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1372           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1373         }
1374         Record.push_back(VE.getValueID(C->getOperand(0)));
1375         Record.push_back(VE.getValueID(C->getOperand(1)));
1376         Record.push_back(VE.getValueID(C->getOperand(2)));
1377         break;
1378       case Instruction::ICmp:
1379       case Instruction::FCmp:
1380         Code = bitc::CST_CODE_CE_CMP;
1381         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1382         Record.push_back(VE.getValueID(C->getOperand(0)));
1383         Record.push_back(VE.getValueID(C->getOperand(1)));
1384         Record.push_back(CE->getPredicate());
1385         break;
1386       }
1387     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1388       Code = bitc::CST_CODE_BLOCKADDRESS;
1389       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1390       Record.push_back(VE.getValueID(BA->getFunction()));
1391       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1392     } else {
1393 #ifndef NDEBUG
1394       C->dump();
1395 #endif
1396       llvm_unreachable("Unknown constant!");
1397     }
1398     Stream.EmitRecord(Code, Record, AbbrevToUse);
1399     Record.clear();
1400   }
1401
1402   Stream.ExitBlock();
1403 }
1404
1405 static void WriteModuleConstants(const ValueEnumerator &VE,
1406                                  BitstreamWriter &Stream) {
1407   const ValueEnumerator::ValueList &Vals = VE.getValues();
1408
1409   // Find the first constant to emit, which is the first non-globalvalue value.
1410   // We know globalvalues have been emitted by WriteModuleInfo.
1411   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1412     if (!isa<GlobalValue>(Vals[i].first)) {
1413       WriteConstants(i, Vals.size(), VE, Stream, true);
1414       return;
1415     }
1416   }
1417 }
1418
1419 /// PushValueAndType - The file has to encode both the value and type id for
1420 /// many values, because we need to know what type to create for forward
1421 /// references.  However, most operands are not forward references, so this type
1422 /// field is not needed.
1423 ///
1424 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1425 /// instruction ID, then it is a forward reference, and it also includes the
1426 /// type ID.  The value ID that is written is encoded relative to the InstID.
1427 static bool PushValueAndType(const Value *V, unsigned InstID,
1428                              SmallVectorImpl<unsigned> &Vals,
1429                              ValueEnumerator &VE) {
1430   unsigned ValID = VE.getValueID(V);
1431   // Make encoding relative to the InstID.
1432   Vals.push_back(InstID - ValID);
1433   if (ValID >= InstID) {
1434     Vals.push_back(VE.getTypeID(V->getType()));
1435     return true;
1436   }
1437   return false;
1438 }
1439
1440 /// pushValue - Like PushValueAndType, but where the type of the value is
1441 /// omitted (perhaps it was already encoded in an earlier operand).
1442 static void pushValue(const Value *V, unsigned InstID,
1443                       SmallVectorImpl<unsigned> &Vals,
1444                       ValueEnumerator &VE) {
1445   unsigned ValID = VE.getValueID(V);
1446   Vals.push_back(InstID - ValID);
1447 }
1448
1449 static void pushValueSigned(const Value *V, unsigned InstID,
1450                             SmallVectorImpl<uint64_t> &Vals,
1451                             ValueEnumerator &VE) {
1452   unsigned ValID = VE.getValueID(V);
1453   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1454   emitSignedInt64(Vals, diff);
1455 }
1456
1457 /// WriteInstruction - Emit an instruction to the specified stream.
1458 static void WriteInstruction(const Instruction &I, unsigned InstID,
1459                              ValueEnumerator &VE, BitstreamWriter &Stream,
1460                              SmallVectorImpl<unsigned> &Vals) {
1461   unsigned Code = 0;
1462   unsigned AbbrevToUse = 0;
1463   VE.setInstructionID(&I);
1464   switch (I.getOpcode()) {
1465   default:
1466     if (Instruction::isCast(I.getOpcode())) {
1467       Code = bitc::FUNC_CODE_INST_CAST;
1468       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1469         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1470       Vals.push_back(VE.getTypeID(I.getType()));
1471       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1472     } else {
1473       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1474       Code = bitc::FUNC_CODE_INST_BINOP;
1475       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1476         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1477       pushValue(I.getOperand(1), InstID, Vals, VE);
1478       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1479       uint64_t Flags = GetOptimizationFlags(&I);
1480       if (Flags != 0) {
1481         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1482           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1483         Vals.push_back(Flags);
1484       }
1485     }
1486     break;
1487
1488   case Instruction::GetElementPtr:
1489     Code = bitc::FUNC_CODE_INST_GEP;
1490     if (cast<GEPOperator>(&I)->isInBounds())
1491       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1492     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1493       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1494     break;
1495   case Instruction::ExtractValue: {
1496     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1497     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1498     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1499     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1500       Vals.push_back(*i);
1501     break;
1502   }
1503   case Instruction::InsertValue: {
1504     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1505     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1506     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1507     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1508     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1509       Vals.push_back(*i);
1510     break;
1511   }
1512   case Instruction::Select:
1513     Code = bitc::FUNC_CODE_INST_VSELECT;
1514     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1515     pushValue(I.getOperand(2), InstID, Vals, VE);
1516     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1517     break;
1518   case Instruction::ExtractElement:
1519     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1520     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1521     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1522     break;
1523   case Instruction::InsertElement:
1524     Code = bitc::FUNC_CODE_INST_INSERTELT;
1525     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1526     pushValue(I.getOperand(1), InstID, Vals, VE);
1527     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1528     break;
1529   case Instruction::ShuffleVector:
1530     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1531     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1532     pushValue(I.getOperand(1), InstID, Vals, VE);
1533     pushValue(I.getOperand(2), InstID, Vals, VE);
1534     break;
1535   case Instruction::ICmp:
1536   case Instruction::FCmp:
1537     // compare returning Int1Ty or vector of Int1Ty
1538     Code = bitc::FUNC_CODE_INST_CMP2;
1539     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1540     pushValue(I.getOperand(1), InstID, Vals, VE);
1541     Vals.push_back(cast<CmpInst>(I).getPredicate());
1542     break;
1543
1544   case Instruction::Ret:
1545     {
1546       Code = bitc::FUNC_CODE_INST_RET;
1547       unsigned NumOperands = I.getNumOperands();
1548       if (NumOperands == 0)
1549         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1550       else if (NumOperands == 1) {
1551         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1552           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1553       } else {
1554         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1555           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1556       }
1557     }
1558     break;
1559   case Instruction::Br:
1560     {
1561       Code = bitc::FUNC_CODE_INST_BR;
1562       const BranchInst &II = cast<BranchInst>(I);
1563       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1564       if (II.isConditional()) {
1565         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1566         pushValue(II.getCondition(), InstID, Vals, VE);
1567       }
1568     }
1569     break;
1570   case Instruction::Switch:
1571     {
1572       Code = bitc::FUNC_CODE_INST_SWITCH;
1573       const SwitchInst &SI = cast<SwitchInst>(I);
1574       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1575       pushValue(SI.getCondition(), InstID, Vals, VE);
1576       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1577       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1578            i != e; ++i) {
1579         Vals.push_back(VE.getValueID(i.getCaseValue()));
1580         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1581       }
1582     }
1583     break;
1584   case Instruction::IndirectBr:
1585     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1586     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1587     // Encode the address operand as relative, but not the basic blocks.
1588     pushValue(I.getOperand(0), InstID, Vals, VE);
1589     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1590       Vals.push_back(VE.getValueID(I.getOperand(i)));
1591     break;
1592
1593   case Instruction::Invoke: {
1594     const InvokeInst *II = cast<InvokeInst>(&I);
1595     const Value *Callee(II->getCalledValue());
1596     PointerType *PTy = cast<PointerType>(Callee->getType());
1597     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1598     Code = bitc::FUNC_CODE_INST_INVOKE;
1599
1600     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1601     Vals.push_back(II->getCallingConv());
1602     Vals.push_back(VE.getValueID(II->getNormalDest()));
1603     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1604     PushValueAndType(Callee, InstID, Vals, VE);
1605
1606     // Emit value #'s for the fixed parameters.
1607     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1608       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1609
1610     // Emit type/value pairs for varargs params.
1611     if (FTy->isVarArg()) {
1612       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1613            i != e; ++i)
1614         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1615     }
1616     break;
1617   }
1618   case Instruction::Resume:
1619     Code = bitc::FUNC_CODE_INST_RESUME;
1620     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1621     break;
1622   case Instruction::Unreachable:
1623     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1624     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1625     break;
1626
1627   case Instruction::PHI: {
1628     const PHINode &PN = cast<PHINode>(I);
1629     Code = bitc::FUNC_CODE_INST_PHI;
1630     // With the newer instruction encoding, forward references could give
1631     // negative valued IDs.  This is most common for PHIs, so we use
1632     // signed VBRs.
1633     SmallVector<uint64_t, 128> Vals64;
1634     Vals64.push_back(VE.getTypeID(PN.getType()));
1635     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1636       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1637       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1638     }
1639     // Emit a Vals64 vector and exit.
1640     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1641     Vals64.clear();
1642     return;
1643   }
1644
1645   case Instruction::LandingPad: {
1646     const LandingPadInst &LP = cast<LandingPadInst>(I);
1647     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1648     Vals.push_back(VE.getTypeID(LP.getType()));
1649     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1650     Vals.push_back(LP.isCleanup());
1651     Vals.push_back(LP.getNumClauses());
1652     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1653       if (LP.isCatch(I))
1654         Vals.push_back(LandingPadInst::Catch);
1655       else
1656         Vals.push_back(LandingPadInst::Filter);
1657       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1658     }
1659     break;
1660   }
1661
1662   case Instruction::Alloca: {
1663     Code = bitc::FUNC_CODE_INST_ALLOCA;
1664     Vals.push_back(VE.getTypeID(I.getType()));
1665     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1666     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1667     const AllocaInst &AI = cast<AllocaInst>(I);
1668     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1669     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1670            "not enough bits for maximum alignment");
1671     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1672     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1673     Vals.push_back(AlignRecord);
1674     break;
1675   }
1676
1677   case Instruction::Load:
1678     if (cast<LoadInst>(I).isAtomic()) {
1679       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1680       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1681     } else {
1682       Code = bitc::FUNC_CODE_INST_LOAD;
1683       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1684         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1685     }
1686     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1687     Vals.push_back(cast<LoadInst>(I).isVolatile());
1688     if (cast<LoadInst>(I).isAtomic()) {
1689       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1690       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1691     }
1692     break;
1693   case Instruction::Store:
1694     if (cast<StoreInst>(I).isAtomic())
1695       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1696     else
1697       Code = bitc::FUNC_CODE_INST_STORE;
1698     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1699     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1700     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1701     Vals.push_back(cast<StoreInst>(I).isVolatile());
1702     if (cast<StoreInst>(I).isAtomic()) {
1703       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1704       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1705     }
1706     break;
1707   case Instruction::AtomicCmpXchg:
1708     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1709     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1710     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1711     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1712     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1713     Vals.push_back(GetEncodedOrdering(
1714                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1715     Vals.push_back(GetEncodedSynchScope(
1716                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1717     Vals.push_back(GetEncodedOrdering(
1718                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1719     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1720     break;
1721   case Instruction::AtomicRMW:
1722     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1723     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1724     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1725     Vals.push_back(GetEncodedRMWOperation(
1726                      cast<AtomicRMWInst>(I).getOperation()));
1727     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1728     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1729     Vals.push_back(GetEncodedSynchScope(
1730                      cast<AtomicRMWInst>(I).getSynchScope()));
1731     break;
1732   case Instruction::Fence:
1733     Code = bitc::FUNC_CODE_INST_FENCE;
1734     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1735     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1736     break;
1737   case Instruction::Call: {
1738     const CallInst &CI = cast<CallInst>(I);
1739     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1740     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1741
1742     Code = bitc::FUNC_CODE_INST_CALL;
1743
1744     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1745     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1746                    unsigned(CI.isMustTailCall()) << 14);
1747     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1748
1749     // Emit value #'s for the fixed parameters.
1750     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1751       // Check for labels (can happen with asm labels).
1752       if (FTy->getParamType(i)->isLabelTy())
1753         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1754       else
1755         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1756     }
1757
1758     // Emit type/value pairs for varargs params.
1759     if (FTy->isVarArg()) {
1760       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1761            i != e; ++i)
1762         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1763     }
1764     break;
1765   }
1766   case Instruction::VAArg:
1767     Code = bitc::FUNC_CODE_INST_VAARG;
1768     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1769     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1770     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1771     break;
1772   }
1773
1774   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1775   Vals.clear();
1776 }
1777
1778 // Emit names for globals/functions etc.
1779 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1780                                   const ValueEnumerator &VE,
1781                                   BitstreamWriter &Stream) {
1782   if (VST.empty()) return;
1783   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1784
1785   // FIXME: Set up the abbrev, we know how many values there are!
1786   // FIXME: We know if the type names can use 7-bit ascii.
1787   SmallVector<unsigned, 64> NameVals;
1788
1789   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1790        SI != SE; ++SI) {
1791
1792     const ValueName &Name = *SI;
1793
1794     // Figure out the encoding to use for the name.
1795     bool is7Bit = true;
1796     bool isChar6 = true;
1797     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1798          C != E; ++C) {
1799       if (isChar6)
1800         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1801       if ((unsigned char)*C & 128) {
1802         is7Bit = false;
1803         break;  // don't bother scanning the rest.
1804       }
1805     }
1806
1807     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1808
1809     // VST_ENTRY:   [valueid, namechar x N]
1810     // VST_BBENTRY: [bbid, namechar x N]
1811     unsigned Code;
1812     if (isa<BasicBlock>(SI->getValue())) {
1813       Code = bitc::VST_CODE_BBENTRY;
1814       if (isChar6)
1815         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1816     } else {
1817       Code = bitc::VST_CODE_ENTRY;
1818       if (isChar6)
1819         AbbrevToUse = VST_ENTRY_6_ABBREV;
1820       else if (is7Bit)
1821         AbbrevToUse = VST_ENTRY_7_ABBREV;
1822     }
1823
1824     NameVals.push_back(VE.getValueID(SI->getValue()));
1825     for (const char *P = Name.getKeyData(),
1826          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1827       NameVals.push_back((unsigned char)*P);
1828
1829     // Emit the finished record.
1830     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1831     NameVals.clear();
1832   }
1833   Stream.ExitBlock();
1834 }
1835
1836 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1837                          BitstreamWriter &Stream) {
1838   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1839   unsigned Code;
1840   if (isa<BasicBlock>(Order.V))
1841     Code = bitc::USELIST_CODE_BB;
1842   else
1843     Code = bitc::USELIST_CODE_DEFAULT;
1844
1845   SmallVector<uint64_t, 64> Record;
1846   for (unsigned I : Order.Shuffle)
1847     Record.push_back(I);
1848   Record.push_back(VE.getValueID(Order.V));
1849   Stream.EmitRecord(Code, Record);
1850 }
1851
1852 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1853                               BitstreamWriter &Stream) {
1854   auto hasMore = [&]() {
1855     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1856   };
1857   if (!hasMore())
1858     // Nothing to do.
1859     return;
1860
1861   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1862   while (hasMore()) {
1863     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1864     VE.UseListOrders.pop_back();
1865   }
1866   Stream.ExitBlock();
1867 }
1868
1869 /// WriteFunction - Emit a function body to the module stream.
1870 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1871                           BitstreamWriter &Stream) {
1872   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1873   VE.incorporateFunction(F);
1874
1875   SmallVector<unsigned, 64> Vals;
1876
1877   // Emit the number of basic blocks, so the reader can create them ahead of
1878   // time.
1879   Vals.push_back(VE.getBasicBlocks().size());
1880   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1881   Vals.clear();
1882
1883   // If there are function-local constants, emit them now.
1884   unsigned CstStart, CstEnd;
1885   VE.getFunctionConstantRange(CstStart, CstEnd);
1886   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1887
1888   // If there is function-local metadata, emit it now.
1889   WriteFunctionLocalMetadata(F, VE, Stream);
1890
1891   // Keep a running idea of what the instruction ID is.
1892   unsigned InstID = CstEnd;
1893
1894   bool NeedsMetadataAttachment = false;
1895
1896   DebugLoc LastDL;
1897
1898   // Finally, emit all the instructions, in order.
1899   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1900     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1901          I != E; ++I) {
1902       WriteInstruction(*I, InstID, VE, Stream, Vals);
1903
1904       if (!I->getType()->isVoidTy())
1905         ++InstID;
1906
1907       // If the instruction has metadata, write a metadata attachment later.
1908       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1909
1910       // If the instruction has a debug location, emit it.
1911       DebugLoc DL = I->getDebugLoc();
1912       if (DL.isUnknown()) {
1913         // nothing todo.
1914       } else if (DL == LastDL) {
1915         // Just repeat the same debug loc as last time.
1916         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1917       } else {
1918         MDNode *Scope, *IA;
1919         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1920         assert(Scope && "Expected valid scope");
1921
1922         Vals.push_back(DL.getLine());
1923         Vals.push_back(DL.getCol());
1924         Vals.push_back(VE.getMetadataOrNullID(Scope));
1925         Vals.push_back(VE.getMetadataOrNullID(IA));
1926         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1927         Vals.clear();
1928
1929         LastDL = DL;
1930       }
1931     }
1932
1933   // Emit names for all the instructions etc.
1934   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1935
1936   if (NeedsMetadataAttachment)
1937     WriteMetadataAttachment(F, VE, Stream);
1938   if (shouldPreserveBitcodeUseListOrder())
1939     WriteUseListBlock(&F, VE, Stream);
1940   VE.purgeFunction();
1941   Stream.ExitBlock();
1942 }
1943
1944 // Emit blockinfo, which defines the standard abbreviations etc.
1945 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1946   // We only want to emit block info records for blocks that have multiple
1947   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1948   // Other blocks can define their abbrevs inline.
1949   Stream.EnterBlockInfoBlock(2);
1950
1951   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1952     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1953     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1954     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1955     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1956     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1957     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1958                                    Abbv) != VST_ENTRY_8_ABBREV)
1959       llvm_unreachable("Unexpected abbrev ordering!");
1960   }
1961
1962   { // 7-bit fixed width VST_ENTRY strings.
1963     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1964     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1965     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1966     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1967     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1968     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1969                                    Abbv) != VST_ENTRY_7_ABBREV)
1970       llvm_unreachable("Unexpected abbrev ordering!");
1971   }
1972   { // 6-bit char6 VST_ENTRY strings.
1973     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1974     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1975     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1976     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1977     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1978     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1979                                    Abbv) != VST_ENTRY_6_ABBREV)
1980       llvm_unreachable("Unexpected abbrev ordering!");
1981   }
1982   { // 6-bit char6 VST_BBENTRY strings.
1983     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1984     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1985     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1986     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1987     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1988     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1989                                    Abbv) != VST_BBENTRY_6_ABBREV)
1990       llvm_unreachable("Unexpected abbrev ordering!");
1991   }
1992
1993
1994
1995   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1996     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1997     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1998     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1999                               Log2_32_Ceil(VE.getTypes().size()+1)));
2000     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2001                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2002       llvm_unreachable("Unexpected abbrev ordering!");
2003   }
2004
2005   { // INTEGER abbrev for CONSTANTS_BLOCK.
2006     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2007     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2008     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2009     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2010                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2011       llvm_unreachable("Unexpected abbrev ordering!");
2012   }
2013
2014   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2015     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2016     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2017     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2018     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2019                               Log2_32_Ceil(VE.getTypes().size()+1)));
2020     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2021
2022     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2023                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2024       llvm_unreachable("Unexpected abbrev ordering!");
2025   }
2026   { // NULL abbrev for CONSTANTS_BLOCK.
2027     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2028     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2029     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2030                                    Abbv) != CONSTANTS_NULL_Abbrev)
2031       llvm_unreachable("Unexpected abbrev ordering!");
2032   }
2033
2034   // FIXME: This should only use space for first class types!
2035
2036   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2037     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2038     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2039     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2040     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2041     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2042     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2043                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2044       llvm_unreachable("Unexpected abbrev ordering!");
2045   }
2046   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2047     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2048     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2049     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2050     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2051     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2052     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2053                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2054       llvm_unreachable("Unexpected abbrev ordering!");
2055   }
2056   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2057     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2058     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2059     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2060     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2061     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2062     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2063     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2064                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2065       llvm_unreachable("Unexpected abbrev ordering!");
2066   }
2067   { // INST_CAST abbrev for FUNCTION_BLOCK.
2068     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2069     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2070     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2071     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2072                               Log2_32_Ceil(VE.getTypes().size()+1)));
2073     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2074     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2075                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2076       llvm_unreachable("Unexpected abbrev ordering!");
2077   }
2078
2079   { // INST_RET abbrev for FUNCTION_BLOCK.
2080     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2081     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2082     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2083                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2084       llvm_unreachable("Unexpected abbrev ordering!");
2085   }
2086   { // INST_RET abbrev for FUNCTION_BLOCK.
2087     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2088     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2089     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2090     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2091                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2092       llvm_unreachable("Unexpected abbrev ordering!");
2093   }
2094   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2095     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2096     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2097     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2098                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2099       llvm_unreachable("Unexpected abbrev ordering!");
2100   }
2101
2102   Stream.ExitBlock();
2103 }
2104
2105 /// WriteModule - Emit the specified module to the bitstream.
2106 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2107   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2108
2109   SmallVector<unsigned, 1> Vals;
2110   unsigned CurVersion = 1;
2111   Vals.push_back(CurVersion);
2112   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2113
2114   // Analyze the module, enumerating globals, functions, etc.
2115   ValueEnumerator VE(*M);
2116
2117   // Emit blockinfo, which defines the standard abbreviations etc.
2118   WriteBlockInfo(VE, Stream);
2119
2120   // Emit information about attribute groups.
2121   WriteAttributeGroupTable(VE, Stream);
2122
2123   // Emit information about parameter attributes.
2124   WriteAttributeTable(VE, Stream);
2125
2126   // Emit information describing all of the types in the module.
2127   WriteTypeTable(VE, Stream);
2128
2129   writeComdats(VE, Stream);
2130
2131   // Emit top-level description of module, including target triple, inline asm,
2132   // descriptors for global variables, and function prototype info.
2133   WriteModuleInfo(M, VE, Stream);
2134
2135   // Emit constants.
2136   WriteModuleConstants(VE, Stream);
2137
2138   // Emit metadata.
2139   WriteModuleMetadata(M, VE, Stream);
2140
2141   // Emit metadata.
2142   WriteModuleMetadataStore(M, Stream);
2143
2144   // Emit names for globals/functions etc.
2145   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2146
2147   // Emit module-level use-lists.
2148   if (shouldPreserveBitcodeUseListOrder())
2149     WriteUseListBlock(nullptr, VE, Stream);
2150
2151   // Emit function bodies.
2152   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2153     if (!F->isDeclaration())
2154       WriteFunction(*F, VE, Stream);
2155
2156   Stream.ExitBlock();
2157 }
2158
2159 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2160 /// header and trailer to make it compatible with the system archiver.  To do
2161 /// this we emit the following header, and then emit a trailer that pads the
2162 /// file out to be a multiple of 16 bytes.
2163 ///
2164 /// struct bc_header {
2165 ///   uint32_t Magic;         // 0x0B17C0DE
2166 ///   uint32_t Version;       // Version, currently always 0.
2167 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2168 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2169 ///   uint32_t CPUType;       // CPU specifier.
2170 ///   ... potentially more later ...
2171 /// };
2172 enum {
2173   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2174   DarwinBCHeaderSize = 5*4
2175 };
2176
2177 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2178                                uint32_t &Position) {
2179   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2180   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2181   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2182   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2183   Position += 4;
2184 }
2185
2186 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2187                                          const Triple &TT) {
2188   unsigned CPUType = ~0U;
2189
2190   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2191   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2192   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2193   // specific constants here because they are implicitly part of the Darwin ABI.
2194   enum {
2195     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2196     DARWIN_CPU_TYPE_X86        = 7,
2197     DARWIN_CPU_TYPE_ARM        = 12,
2198     DARWIN_CPU_TYPE_POWERPC    = 18
2199   };
2200
2201   Triple::ArchType Arch = TT.getArch();
2202   if (Arch == Triple::x86_64)
2203     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2204   else if (Arch == Triple::x86)
2205     CPUType = DARWIN_CPU_TYPE_X86;
2206   else if (Arch == Triple::ppc)
2207     CPUType = DARWIN_CPU_TYPE_POWERPC;
2208   else if (Arch == Triple::ppc64)
2209     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2210   else if (Arch == Triple::arm || Arch == Triple::thumb)
2211     CPUType = DARWIN_CPU_TYPE_ARM;
2212
2213   // Traditional Bitcode starts after header.
2214   assert(Buffer.size() >= DarwinBCHeaderSize &&
2215          "Expected header size to be reserved");
2216   unsigned BCOffset = DarwinBCHeaderSize;
2217   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2218
2219   // Write the magic and version.
2220   unsigned Position = 0;
2221   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2222   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2223   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2224   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2225   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2226
2227   // If the file is not a multiple of 16 bytes, insert dummy padding.
2228   while (Buffer.size() & 15)
2229     Buffer.push_back(0);
2230 }
2231
2232 /// WriteBitcodeToFile - Write the specified module to the specified output
2233 /// stream.
2234 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2235   SmallVector<char, 0> Buffer;
2236   Buffer.reserve(256*1024);
2237
2238   // If this is darwin or another generic macho target, reserve space for the
2239   // header.
2240   Triple TT(M->getTargetTriple());
2241   if (TT.isOSDarwin())
2242     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2243
2244   // Emit the module into the buffer.
2245   {
2246     BitstreamWriter Stream(Buffer);
2247
2248     // Emit the file header.
2249     Stream.Emit((unsigned)'B', 8);
2250     Stream.Emit((unsigned)'C', 8);
2251     Stream.Emit(0x0, 4);
2252     Stream.Emit(0xC, 4);
2253     Stream.Emit(0xE, 4);
2254     Stream.Emit(0xD, 4);
2255
2256     // Emit the module.
2257     WriteModule(M, Stream);
2258   }
2259
2260   if (TT.isOSDarwin())
2261     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2262
2263   // Write the generated bitstream to "Out".
2264   Out.write((char*)&Buffer.front(), Buffer.size());
2265 }