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 *N,
 857                                const ValueEnumerator &VE,
 858                                BitstreamWriter &Stream,
 859                                SmallVectorImpl<uint64_t> &Record,
 860                                unsigned Abbrev) {
 861   Record.push_back(N->isDistinct());
 862   Record.push_back(N->getTag());
 863   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 864   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 865   Record.push_back(N->getLine());
 866   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 867   Record.push_back(VE.getMetadataID(N->getBaseType()));
 868   Record.push_back(N->getSizeInBits());
 869   Record.push_back(N->getAlignInBits());
 870   Record.push_back(N->getOffsetInBits());
 871   Record.push_back(N->getFlags());
 872   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
 873
 874   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
 875   Record.clear();
 876 }
 877
 878 static void WriteMDCompositeType(const MDCompositeType *N,
 879                                  const ValueEnumerator &VE,
 880                                  BitstreamWriter &Stream,
 881                                  SmallVectorImpl<uint64_t> &Record,
 882                                  unsigned Abbrev) {
 883   Record.push_back(N->isDistinct());
 884   Record.push_back(N->getTag());
 885   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 886   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 887   Record.push_back(N->getLine());
 888   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 889   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
 890   Record.push_back(N->getSizeInBits());
 891   Record.push_back(N->getAlignInBits());
 892   Record.push_back(N->getOffsetInBits());
 893   Record.push_back(N->getFlags());
 894   Record.push_back(VE.getMetadataOrNullID(N->getElements()));
 895   Record.push_back(N->getRuntimeLang());
 896   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
 897   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
 898   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
 899
 900   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
 901   Record.clear();
 902 }
 903
 904 static void WriteMDSubroutineType(const MDSubroutineType *N,
 905                                   const ValueEnumerator &VE,
 906                                   BitstreamWriter &Stream,
 907                                   SmallVectorImpl<uint64_t> &Record,
 908                                   unsigned Abbrev) {
 909   Record.push_back(N->isDistinct());
 910   Record.push_back(N->getFlags());
 911   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray()));
 912
 913   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
 914   Record.clear();
 915 }
 916
 917 static void WriteMDFile(const MDFile *N, const ValueEnumerator &VE,
 918                         BitstreamWriter &Stream,
 919                         SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 920   Record.push_back(N->isDistinct());
 921   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
 922   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
 923
 924   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
 925   Record.clear();
 926 }
 927
 928 static void WriteMDCompileUnit(const MDCompileUnit *N,
 929                                const ValueEnumerator &VE,
 930                                BitstreamWriter &Stream,
 931                                SmallVectorImpl<uint64_t> &Record,
 932                                unsigned Abbrev) {
 933   Record.push_back(N->isDistinct());
 934   Record.push_back(N->getSourceLanguage());
 935   Record.push_back(VE.getMetadataID(N->getFile()));
 936   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
 937   Record.push_back(N->isOptimized());
 938   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
 939   Record.push_back(N->getRuntimeVersion());
 940   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
 941   Record.push_back(N->getEmissionKind());
 942   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes()));
 943   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes()));
 944   Record.push_back(VE.getMetadataOrNullID(N->getSubprograms()));
 945   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables()));
 946   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities()));
 947
 948   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
 949   Record.clear();
 950 }
 951
 952 static void WriteMDSubprogram(const MDSubprogram *N,
 953                                const ValueEnumerator &VE,
 954                                BitstreamWriter &Stream,
 955                                SmallVectorImpl<uint64_t> &Record,
 956                                unsigned Abbrev) {
 957   Record.push_back(N->isDistinct());
 958   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 959   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 960   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
 961   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 962   Record.push_back(N->getLine());
 963   Record.push_back(VE.getMetadataOrNullID(N->getType()));
 964   Record.push_back(N->isLocalToUnit());
 965   Record.push_back(N->isDefinition());
 966   Record.push_back(N->getScopeLine());
 967   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
 968   Record.push_back(N->getVirtuality());
 969   Record.push_back(N->getVirtualIndex());
 970   Record.push_back(N->getFlags());
 971   Record.push_back(N->isOptimized());
 972   Record.push_back(VE.getMetadataOrNullID(N->getFunction()));
 973   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
 974   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
 975   Record.push_back(VE.getMetadataOrNullID(N->getVariables()));
 976
 977   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
 978   Record.clear();
 979 }
 980
 981 static void WriteMDLexicalBlock(const MDLexicalBlock *N,
 982                                const ValueEnumerator &VE,
 983                                BitstreamWriter &Stream,
 984                                SmallVectorImpl<uint64_t> &Record,
 985                                unsigned Abbrev) {
 986   Record.push_back(N->isDistinct());
 987   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
 988   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
 989   Record.push_back(N->getLine());
 990   Record.push_back(N->getColumn());
 991
 992   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
 993   Record.clear();
 994 }
 995
 996 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *N,
 997                                     const ValueEnumerator &VE,
 998                                     BitstreamWriter &Stream,
 999                                     SmallVectorImpl<uint64_t> &Record,
1000                                     unsigned Abbrev) {
1001   Record.push_back(N->isDistinct());
1002   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1003   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1004   Record.push_back(N->getDiscriminator());
1005
1006   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1007   Record.clear();
1008 }
1009
1010 static void WriteMDNamespace(const MDNamespace *N, const ValueEnumerator &VE,
1011                              BitstreamWriter &Stream,
1012                              SmallVectorImpl<uint64_t> &Record,
1013                              unsigned Abbrev) {
1014   Record.push_back(N->isDistinct());
1015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1016   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1017   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1018   Record.push_back(N->getLine());
1019
1020   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1021   Record.clear();
1022 }
1023
1024 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *N,
1025                                          const ValueEnumerator &VE,
1026                                          BitstreamWriter &Stream,
1027                                          SmallVectorImpl<uint64_t> &Record,
1028                                          unsigned Abbrev) {
1029   Record.push_back(N->isDistinct());
1030   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1031   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1032   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1033
1034   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1035   Record.clear();
1036 }
1037
1038 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *N,
1039                                           const ValueEnumerator &VE,
1040                                           BitstreamWriter &Stream,
1041                                           SmallVectorImpl<uint64_t> &Record,
1042                                           unsigned Abbrev) {
1043   Record.push_back(N->isDistinct());
1044   Record.push_back(N->getTag());
1045   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1046   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1047   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1048   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1049
1050   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1051   Record.clear();
1052 }
1053
1054 static void WriteMDGlobalVariable(const MDGlobalVariable *N,
1055                                   const ValueEnumerator &VE,
1056                                   BitstreamWriter &Stream,
1057                                   SmallVectorImpl<uint64_t> &Record,
1058                                   unsigned Abbrev) {
1059   Record.push_back(N->isDistinct());
1060   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1061   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1062   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1063   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1064   Record.push_back(N->getLine());
1065   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1066   Record.push_back(N->isLocalToUnit());
1067   Record.push_back(N->isDefinition());
1068   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1069   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1070
1071   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1072   Record.clear();
1073 }
1074
1075 static void WriteMDLocalVariable(const MDLocalVariable *N,
1076                                  const ValueEnumerator &VE,
1077                                  BitstreamWriter &Stream,
1078                                  SmallVectorImpl<uint64_t> &Record,
1079                                  unsigned Abbrev) {
1080   Record.push_back(N->isDistinct());
1081   Record.push_back(N->getTag());
1082   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1083   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1084   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1085   Record.push_back(N->getLine());
1086   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1087   Record.push_back(N->getArg());
1088   Record.push_back(N->getFlags());
1089   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1090
1091   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1092   Record.clear();
1093 }
1094
1095 static void WriteMDExpression(const MDExpression *N, const ValueEnumerator &,
1096                               BitstreamWriter &Stream,
1097                               SmallVectorImpl<uint64_t> &Record,
1098                               unsigned Abbrev) {
1099   Record.reserve(N->getElements().size() + 1);
1100
1101   Record.push_back(N->isDistinct());
1102   Record.append(N->elements_begin(), N->elements_end());
1103
1104   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1105   Record.clear();
1106 }
1107
1108 static void WriteMDObjCProperty(const MDObjCProperty *N,
1109                                  const ValueEnumerator &VE,
1110                                  BitstreamWriter &Stream,
1111                                  SmallVectorImpl<uint64_t> &Record,
1112                                  unsigned Abbrev) {
1113   Record.push_back(N->isDistinct());
1114   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1115   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1116   Record.push_back(N->getLine());
1117   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1118   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1119   Record.push_back(N->getAttributes());
1120   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1121
1122   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1123   Record.clear();
1124 }
1125
1126 static void WriteMDImportedEntity(const MDImportedEntity *N,
1127                                   const ValueEnumerator &VE,
1128                                   BitstreamWriter &Stream,
1129                                   SmallVectorImpl<uint64_t> &Record,
1130                                   unsigned Abbrev) {
1131   Record.push_back(N->isDistinct());
1132   Record.push_back(N->getTag());
1133   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1134   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1135   Record.push_back(N->getLine());
1136   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1137
1138   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1139   Record.clear();
1140 }
1141
1142 static void WriteModuleMetadata(const Module *M,
1143                                 const ValueEnumerator &VE,
1144                                 BitstreamWriter &Stream) {
1145   const auto &MDs = VE.getMDs();
1146   if (MDs.empty() && M->named_metadata_empty())
1147     return;
1148
1149   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1150
1151   unsigned MDSAbbrev = 0;
1152   if (VE.hasMDString()) {
1153     // Abbrev for METADATA_STRING.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1158     MDSAbbrev = Stream.EmitAbbrev(Abbv);
1159   }
1160
1161   // Initialize MDNode abbreviations.
1162 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1163 #include "llvm/IR/Metadata.def"
1164
1165   if (VE.hasMDLocation()) {
1166     // Abbrev for METADATA_LOCATION.
1167     //
1168     // Assume the column is usually under 128, and always output the inlined-at
1169     // location (it's never more expensive than building an array size 1).
1170     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1171     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1172     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1174     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1177     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
1178   }
1179
1180   if (VE.hasGenericDebugNode()) {
1181     // Abbrev for METADATA_GENERIC_DEBUG.
1182     //
1183     // Assume the column is usually under 128, and always output the inlined-at
1184     // location (it's never more expensive than building an array size 1).
1185     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1186     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1193     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
1194   }
1195
1196   unsigned NameAbbrev = 0;
1197   if (!M->named_metadata_empty()) {
1198     // Abbrev for METADATA_NAME.
1199     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1200     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1201     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1202     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1203     NameAbbrev = Stream.EmitAbbrev(Abbv);
1204   }
1205
1206   SmallVector<uint64_t, 64> Record;
1207   for (const Metadata *MD : MDs) {
1208     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1209       switch (N->getMetadataID()) {
1210       default:
1211         llvm_unreachable("Invalid MDNode subclass");
1212 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1213   case Metadata::CLASS##Kind:                                                  \
1214     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1215     continue;
1216 #include "llvm/IR/Metadata.def"
1217       }
1218     }
1219     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1220       WriteValueAsMetadata(MDC, VE, Stream, Record);
1221       continue;
1222     }
1223     const MDString *MDS = cast<MDString>(MD);
1224     // Code: [strchar x N]
1225     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1226
1227     // Emit the finished record.
1228     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1229     Record.clear();
1230   }
1231
1232   // Write named metadata.
1233   for (const NamedMDNode &NMD : M->named_metadata()) {
1234     // Write name.
1235     StringRef Str = NMD.getName();
1236     Record.append(Str.bytes_begin(), Str.bytes_end());
1237     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1238     Record.clear();
1239
1240     // Write named metadata operands.
1241     for (const MDNode *N : NMD.operands())
1242       Record.push_back(VE.getMetadataID(N));
1243     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1244     Record.clear();
1245   }
1246
1247   Stream.ExitBlock();
1248 }
1249
1250 static void WriteFunctionLocalMetadata(const Function &F,
1251                                        const ValueEnumerator &VE,
1252                                        BitstreamWriter &Stream) {
1253   bool StartedMetadataBlock = false;
1254   SmallVector<uint64_t, 64> Record;
1255   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1256       VE.getFunctionLocalMDs();
1257   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1258     assert(MDs[i] && "Expected valid function-local metadata");
1259     if (!StartedMetadataBlock) {
1260       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1261       StartedMetadataBlock = true;
1262     }
1263     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1264   }
1265
1266   if (StartedMetadataBlock)
1267     Stream.ExitBlock();
1268 }
1269
1270 static void WriteMetadataAttachment(const Function &F,
1271                                     const ValueEnumerator &VE,
1272                                     BitstreamWriter &Stream) {
1273   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1274
1275   SmallVector<uint64_t, 64> Record;
1276
1277   // Write metadata attachments
1278   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1279   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1280
1281   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1282     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1283          I != E; ++I) {
1284       MDs.clear();
1285       I->getAllMetadataOtherThanDebugLoc(MDs);
1286
1287       // If no metadata, ignore instruction.
1288       if (MDs.empty()) continue;
1289
1290       Record.push_back(VE.getInstructionID(I));
1291
1292       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1293         Record.push_back(MDs[i].first);
1294         Record.push_back(VE.getMetadataID(MDs[i].second));
1295       }
1296       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1297       Record.clear();
1298     }
1299
1300   Stream.ExitBlock();
1301 }
1302
1303 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1304   SmallVector<uint64_t, 64> Record;
1305
1306   // Write metadata kinds
1307   // METADATA_KIND - [n x [id, name]]
1308   SmallVector<StringRef, 8> Names;
1309   M->getMDKindNames(Names);
1310
1311   if (Names.empty()) return;
1312
1313   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1314
1315   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1316     Record.push_back(MDKindID);
1317     StringRef KName = Names[MDKindID];
1318     Record.append(KName.begin(), KName.end());
1319
1320     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1321     Record.clear();
1322   }
1323
1324   Stream.ExitBlock();
1325 }
1326
1327 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1328   if ((int64_t)V >= 0)
1329     Vals.push_back(V << 1);
1330   else
1331     Vals.push_back((-V << 1) | 1);
1332 }
1333
1334 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1335                            const ValueEnumerator &VE,
1336                            BitstreamWriter &Stream, bool isGlobal) {
1337   if (FirstVal == LastVal) return;
1338
1339   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1340
1341   unsigned AggregateAbbrev = 0;
1342   unsigned String8Abbrev = 0;
1343   unsigned CString7Abbrev = 0;
1344   unsigned CString6Abbrev = 0;
1345   // If this is a constant pool for the module, emit module-specific abbrevs.
1346   if (isGlobal) {
1347     // Abbrev for CST_CODE_AGGREGATE.
1348     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1349     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1352     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1353
1354     // Abbrev for CST_CODE_STRING.
1355     Abbv = new BitCodeAbbrev();
1356     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1359     String8Abbrev = Stream.EmitAbbrev(Abbv);
1360     // Abbrev for CST_CODE_CSTRING.
1361     Abbv = new BitCodeAbbrev();
1362     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1363     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1365     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1366     // Abbrev for CST_CODE_CSTRING.
1367     Abbv = new BitCodeAbbrev();
1368     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1371     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1372   }
1373
1374   SmallVector<uint64_t, 64> Record;
1375
1376   const ValueEnumerator::ValueList &Vals = VE.getValues();
1377   Type *LastTy = nullptr;
1378   for (unsigned i = FirstVal; i != LastVal; ++i) {
1379     const Value *V = Vals[i].first;
1380     // If we need to switch types, do so now.
1381     if (V->getType() != LastTy) {
1382       LastTy = V->getType();
1383       Record.push_back(VE.getTypeID(LastTy));
1384       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1385                         CONSTANTS_SETTYPE_ABBREV);
1386       Record.clear();
1387     }
1388
1389     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1390       Record.push_back(unsigned(IA->hasSideEffects()) |
1391                        unsigned(IA->isAlignStack()) << 1 |
1392                        unsigned(IA->getDialect()&1) << 2);
1393
1394       // Add the asm string.
1395       const std::string &AsmStr = IA->getAsmString();
1396       Record.push_back(AsmStr.size());
1397       Record.append(AsmStr.begin(), AsmStr.end());
1398
1399       // Add the constraint string.
1400       const std::string &ConstraintStr = IA->getConstraintString();
1401       Record.push_back(ConstraintStr.size());
1402       Record.append(ConstraintStr.begin(), ConstraintStr.end());
1403       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1404       Record.clear();
1405       continue;
1406     }
1407     const Constant *C = cast<Constant>(V);
1408     unsigned Code = -1U;
1409     unsigned AbbrevToUse = 0;
1410     if (C->isNullValue()) {
1411       Code = bitc::CST_CODE_NULL;
1412     } else if (isa<UndefValue>(C)) {
1413       Code = bitc::CST_CODE_UNDEF;
1414     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1415       if (IV->getBitWidth() <= 64) {
1416         uint64_t V = IV->getSExtValue();
1417         emitSignedInt64(Record, V);
1418         Code = bitc::CST_CODE_INTEGER;
1419         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1420       } else {                             // Wide integers, > 64 bits in size.
1421         // We have an arbitrary precision integer value to write whose
1422         // bit width is > 64. However, in canonical unsigned integer
1423         // format it is likely that the high bits are going to be zero.
1424         // So, we only write the number of active words.
1425         unsigned NWords = IV->getValue().getActiveWords();
1426         const uint64_t *RawWords = IV->getValue().getRawData();
1427         for (unsigned i = 0; i != NWords; ++i) {
1428           emitSignedInt64(Record, RawWords[i]);
1429         }
1430         Code = bitc::CST_CODE_WIDE_INTEGER;
1431       }
1432     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1433       Code = bitc::CST_CODE_FLOAT;
1434       Type *Ty = CFP->getType();
1435       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1436         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1437       } else if (Ty->isX86_FP80Ty()) {
1438         // api needed to prevent premature destruction
1439         // bits are not in the same order as a normal i80 APInt, compensate.
1440         APInt api = CFP->getValueAPF().bitcastToAPInt();
1441         const uint64_t *p = api.getRawData();
1442         Record.push_back((p[1] << 48) | (p[0] >> 16));
1443         Record.push_back(p[0] & 0xffffLL);
1444       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1445         APInt api = CFP->getValueAPF().bitcastToAPInt();
1446         const uint64_t *p = api.getRawData();
1447         Record.push_back(p[0]);
1448         Record.push_back(p[1]);
1449       } else {
1450         assert (0 && "Unknown FP type!");
1451       }
1452     } else if (isa<ConstantDataSequential>(C) &&
1453                cast<ConstantDataSequential>(C)->isString()) {
1454       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1455       // Emit constant strings specially.
1456       unsigned NumElts = Str->getNumElements();
1457       // If this is a null-terminated string, use the denser CSTRING encoding.
1458       if (Str->isCString()) {
1459         Code = bitc::CST_CODE_CSTRING;
1460         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1461       } else {
1462         Code = bitc::CST_CODE_STRING;
1463         AbbrevToUse = String8Abbrev;
1464       }
1465       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1466       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1467       for (unsigned i = 0; i != NumElts; ++i) {
1468         unsigned char V = Str->getElementAsInteger(i);
1469         Record.push_back(V);
1470         isCStr7 &= (V & 128) == 0;
1471         if (isCStrChar6)
1472           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1473       }
1474
1475       if (isCStrChar6)
1476         AbbrevToUse = CString6Abbrev;
1477       else if (isCStr7)
1478         AbbrevToUse = CString7Abbrev;
1479     } else if (const ConstantDataSequential *CDS =
1480                   dyn_cast<ConstantDataSequential>(C)) {
1481       Code = bitc::CST_CODE_DATA;
1482       Type *EltTy = CDS->getType()->getElementType();
1483       if (isa<IntegerType>(EltTy)) {
1484         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1485           Record.push_back(CDS->getElementAsInteger(i));
1486       } else if (EltTy->isFloatTy()) {
1487         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1488           union { float F; uint32_t I; };
1489           F = CDS->getElementAsFloat(i);
1490           Record.push_back(I);
1491         }
1492       } else {
1493         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1494         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1495           union { double F; uint64_t I; };
1496           F = CDS->getElementAsDouble(i);
1497           Record.push_back(I);
1498         }
1499       }
1500     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1501                isa<ConstantVector>(C)) {
1502       Code = bitc::CST_CODE_AGGREGATE;
1503       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1504         Record.push_back(VE.getValueID(C->getOperand(i)));
1505       AbbrevToUse = AggregateAbbrev;
1506     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1507       switch (CE->getOpcode()) {
1508       default:
1509         if (Instruction::isCast(CE->getOpcode())) {
1510           Code = bitc::CST_CODE_CE_CAST;
1511           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1512           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1513           Record.push_back(VE.getValueID(C->getOperand(0)));
1514           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1515         } else {
1516           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1517           Code = bitc::CST_CODE_CE_BINOP;
1518           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1519           Record.push_back(VE.getValueID(C->getOperand(0)));
1520           Record.push_back(VE.getValueID(C->getOperand(1)));
1521           uint64_t Flags = GetOptimizationFlags(CE);
1522           if (Flags != 0)
1523             Record.push_back(Flags);
1524         }
1525         break;
1526       case Instruction::GetElementPtr:
1527         Code = bitc::CST_CODE_CE_GEP;
1528         if (cast<GEPOperator>(C)->isInBounds())
1529           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1530         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1531           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1532           Record.push_back(VE.getValueID(C->getOperand(i)));
1533         }
1534         break;
1535       case Instruction::Select:
1536         Code = bitc::CST_CODE_CE_SELECT;
1537         Record.push_back(VE.getValueID(C->getOperand(0)));
1538         Record.push_back(VE.getValueID(C->getOperand(1)));
1539         Record.push_back(VE.getValueID(C->getOperand(2)));
1540         break;
1541       case Instruction::ExtractElement:
1542         Code = bitc::CST_CODE_CE_EXTRACTELT;
1543         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1544         Record.push_back(VE.getValueID(C->getOperand(0)));
1545         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1546         Record.push_back(VE.getValueID(C->getOperand(1)));
1547         break;
1548       case Instruction::InsertElement:
1549         Code = bitc::CST_CODE_CE_INSERTELT;
1550         Record.push_back(VE.getValueID(C->getOperand(0)));
1551         Record.push_back(VE.getValueID(C->getOperand(1)));
1552         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1553         Record.push_back(VE.getValueID(C->getOperand(2)));
1554         break;
1555       case Instruction::ShuffleVector:
1556         // If the return type and argument types are the same, this is a
1557         // standard shufflevector instruction.  If the types are different,
1558         // then the shuffle is widening or truncating the input vectors, and
1559         // the argument type must also be encoded.
1560         if (C->getType() == C->getOperand(0)->getType()) {
1561           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1562         } else {
1563           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1564           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1565         }
1566         Record.push_back(VE.getValueID(C->getOperand(0)));
1567         Record.push_back(VE.getValueID(C->getOperand(1)));
1568         Record.push_back(VE.getValueID(C->getOperand(2)));
1569         break;
1570       case Instruction::ICmp:
1571       case Instruction::FCmp:
1572         Code = bitc::CST_CODE_CE_CMP;
1573         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1574         Record.push_back(VE.getValueID(C->getOperand(0)));
1575         Record.push_back(VE.getValueID(C->getOperand(1)));
1576         Record.push_back(CE->getPredicate());
1577         break;
1578       }
1579     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1580       Code = bitc::CST_CODE_BLOCKADDRESS;
1581       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1582       Record.push_back(VE.getValueID(BA->getFunction()));
1583       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1584     } else {
1585 #ifndef NDEBUG
1586       C->dump();
1587 #endif
1588       llvm_unreachable("Unknown constant!");
1589     }
1590     Stream.EmitRecord(Code, Record, AbbrevToUse);
1591     Record.clear();
1592   }
1593
1594   Stream.ExitBlock();
1595 }
1596
1597 static void WriteModuleConstants(const ValueEnumerator &VE,
1598                                  BitstreamWriter &Stream) {
1599   const ValueEnumerator::ValueList &Vals = VE.getValues();
1600
1601   // Find the first constant to emit, which is the first non-globalvalue value.
1602   // We know globalvalues have been emitted by WriteModuleInfo.
1603   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1604     if (!isa<GlobalValue>(Vals[i].first)) {
1605       WriteConstants(i, Vals.size(), VE, Stream, true);
1606       return;
1607     }
1608   }
1609 }
1610
1611 /// PushValueAndType - The file has to encode both the value and type id for
1612 /// many values, because we need to know what type to create for forward
1613 /// references.  However, most operands are not forward references, so this type
1614 /// field is not needed.
1615 ///
1616 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1617 /// instruction ID, then it is a forward reference, and it also includes the
1618 /// type ID.  The value ID that is written is encoded relative to the InstID.
1619 static bool PushValueAndType(const Value *V, unsigned InstID,
1620                              SmallVectorImpl<unsigned> &Vals,
1621                              ValueEnumerator &VE) {
1622   unsigned ValID = VE.getValueID(V);
1623   // Make encoding relative to the InstID.
1624   Vals.push_back(InstID - ValID);
1625   if (ValID >= InstID) {
1626     Vals.push_back(VE.getTypeID(V->getType()));
1627     return true;
1628   }
1629   return false;
1630 }
1631
1632 /// pushValue - Like PushValueAndType, but where the type of the value is
1633 /// omitted (perhaps it was already encoded in an earlier operand).
1634 static void pushValue(const Value *V, unsigned InstID,
1635                       SmallVectorImpl<unsigned> &Vals,
1636                       ValueEnumerator &VE) {
1637   unsigned ValID = VE.getValueID(V);
1638   Vals.push_back(InstID - ValID);
1639 }
1640
1641 static void pushValueSigned(const Value *V, unsigned InstID,
1642                             SmallVectorImpl<uint64_t> &Vals,
1643                             ValueEnumerator &VE) {
1644   unsigned ValID = VE.getValueID(V);
1645   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1646   emitSignedInt64(Vals, diff);
1647 }
1648
1649 /// WriteInstruction - Emit an instruction to the specified stream.
1650 static void WriteInstruction(const Instruction &I, unsigned InstID,
1651                              ValueEnumerator &VE, BitstreamWriter &Stream,
1652                              SmallVectorImpl<unsigned> &Vals) {
1653   unsigned Code = 0;
1654   unsigned AbbrevToUse = 0;
1655   VE.setInstructionID(&I);
1656   switch (I.getOpcode()) {
1657   default:
1658     if (Instruction::isCast(I.getOpcode())) {
1659       Code = bitc::FUNC_CODE_INST_CAST;
1660       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1661         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1662       Vals.push_back(VE.getTypeID(I.getType()));
1663       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1664     } else {
1665       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1666       Code = bitc::FUNC_CODE_INST_BINOP;
1667       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1668         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1669       pushValue(I.getOperand(1), InstID, Vals, VE);
1670       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1671       uint64_t Flags = GetOptimizationFlags(&I);
1672       if (Flags != 0) {
1673         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1674           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1675         Vals.push_back(Flags);
1676       }
1677     }
1678     break;
1679
1680   case Instruction::GetElementPtr:
1681     Code = bitc::FUNC_CODE_INST_GEP;
1682     if (cast<GEPOperator>(&I)->isInBounds())
1683       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1684     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1685       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1686     break;
1687   case Instruction::ExtractValue: {
1688     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1689     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1690     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1691     Vals.append(EVI->idx_begin(), EVI->idx_end());
1692     break;
1693   }
1694   case Instruction::InsertValue: {
1695     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1696     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1697     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1698     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1699     Vals.append(IVI->idx_begin(), IVI->idx_end());
1700     break;
1701   }
1702   case Instruction::Select:
1703     Code = bitc::FUNC_CODE_INST_VSELECT;
1704     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1705     pushValue(I.getOperand(2), InstID, Vals, VE);
1706     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1707     break;
1708   case Instruction::ExtractElement:
1709     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1710     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1711     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1712     break;
1713   case Instruction::InsertElement:
1714     Code = bitc::FUNC_CODE_INST_INSERTELT;
1715     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1716     pushValue(I.getOperand(1), InstID, Vals, VE);
1717     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1718     break;
1719   case Instruction::ShuffleVector:
1720     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1721     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1722     pushValue(I.getOperand(1), InstID, Vals, VE);
1723     pushValue(I.getOperand(2), InstID, Vals, VE);
1724     break;
1725   case Instruction::ICmp:
1726   case Instruction::FCmp:
1727     // compare returning Int1Ty or vector of Int1Ty
1728     Code = bitc::FUNC_CODE_INST_CMP2;
1729     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1730     pushValue(I.getOperand(1), InstID, Vals, VE);
1731     Vals.push_back(cast<CmpInst>(I).getPredicate());
1732     break;
1733
1734   case Instruction::Ret:
1735     {
1736       Code = bitc::FUNC_CODE_INST_RET;
1737       unsigned NumOperands = I.getNumOperands();
1738       if (NumOperands == 0)
1739         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1740       else if (NumOperands == 1) {
1741         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1742           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1743       } else {
1744         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1745           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1746       }
1747     }
1748     break;
1749   case Instruction::Br:
1750     {
1751       Code = bitc::FUNC_CODE_INST_BR;
1752       const BranchInst &II = cast<BranchInst>(I);
1753       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1754       if (II.isConditional()) {
1755         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1756         pushValue(II.getCondition(), InstID, Vals, VE);
1757       }
1758     }
1759     break;
1760   case Instruction::Switch:
1761     {
1762       Code = bitc::FUNC_CODE_INST_SWITCH;
1763       const SwitchInst &SI = cast<SwitchInst>(I);
1764       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1765       pushValue(SI.getCondition(), InstID, Vals, VE);
1766       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1767       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1768            i != e; ++i) {
1769         Vals.push_back(VE.getValueID(i.getCaseValue()));
1770         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1771       }
1772     }
1773     break;
1774   case Instruction::IndirectBr:
1775     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1776     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1777     // Encode the address operand as relative, but not the basic blocks.
1778     pushValue(I.getOperand(0), InstID, Vals, VE);
1779     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1780       Vals.push_back(VE.getValueID(I.getOperand(i)));
1781     break;
1782
1783   case Instruction::Invoke: {
1784     const InvokeInst *II = cast<InvokeInst>(&I);
1785     const Value *Callee(II->getCalledValue());
1786     PointerType *PTy = cast<PointerType>(Callee->getType());
1787     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1788     Code = bitc::FUNC_CODE_INST_INVOKE;
1789
1790     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1791     Vals.push_back(II->getCallingConv());
1792     Vals.push_back(VE.getValueID(II->getNormalDest()));
1793     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1794     PushValueAndType(Callee, InstID, Vals, VE);
1795
1796     // Emit value #'s for the fixed parameters.
1797     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1798       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1799
1800     // Emit type/value pairs for varargs params.
1801     if (FTy->isVarArg()) {
1802       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1803            i != e; ++i)
1804         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1805     }
1806     break;
1807   }
1808   case Instruction::Resume:
1809     Code = bitc::FUNC_CODE_INST_RESUME;
1810     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1811     break;
1812   case Instruction::Unreachable:
1813     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1814     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1815     break;
1816
1817   case Instruction::PHI: {
1818     const PHINode &PN = cast<PHINode>(I);
1819     Code = bitc::FUNC_CODE_INST_PHI;
1820     // With the newer instruction encoding, forward references could give
1821     // negative valued IDs.  This is most common for PHIs, so we use
1822     // signed VBRs.
1823     SmallVector<uint64_t, 128> Vals64;
1824     Vals64.push_back(VE.getTypeID(PN.getType()));
1825     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1826       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1827       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1828     }
1829     // Emit a Vals64 vector and exit.
1830     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1831     Vals64.clear();
1832     return;
1833   }
1834
1835   case Instruction::LandingPad: {
1836     const LandingPadInst &LP = cast<LandingPadInst>(I);
1837     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1838     Vals.push_back(VE.getTypeID(LP.getType()));
1839     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1840     Vals.push_back(LP.isCleanup());
1841     Vals.push_back(LP.getNumClauses());
1842     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1843       if (LP.isCatch(I))
1844         Vals.push_back(LandingPadInst::Catch);
1845       else
1846         Vals.push_back(LandingPadInst::Filter);
1847       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1848     }
1849     break;
1850   }
1851
1852   case Instruction::Alloca: {
1853     Code = bitc::FUNC_CODE_INST_ALLOCA;
1854     Vals.push_back(VE.getTypeID(I.getType()));
1855     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1856     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1857     const AllocaInst &AI = cast<AllocaInst>(I);
1858     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1859     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1860            "not enough bits for maximum alignment");
1861     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1862     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1863     Vals.push_back(AlignRecord);
1864     break;
1865   }
1866
1867   case Instruction::Load:
1868     if (cast<LoadInst>(I).isAtomic()) {
1869       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1870       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1871     } else {
1872       Code = bitc::FUNC_CODE_INST_LOAD;
1873       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1874         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1875     }
1876     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1877     Vals.push_back(cast<LoadInst>(I).isVolatile());
1878     if (cast<LoadInst>(I).isAtomic()) {
1879       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1880       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1881     }
1882     break;
1883   case Instruction::Store:
1884     if (cast<StoreInst>(I).isAtomic())
1885       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1886     else
1887       Code = bitc::FUNC_CODE_INST_STORE;
1888     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1889     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1890     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1891     Vals.push_back(cast<StoreInst>(I).isVolatile());
1892     if (cast<StoreInst>(I).isAtomic()) {
1893       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1894       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1895     }
1896     break;
1897   case Instruction::AtomicCmpXchg:
1898     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1899     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1900     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1901     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1902     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1903     Vals.push_back(GetEncodedOrdering(
1904                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1905     Vals.push_back(GetEncodedSynchScope(
1906                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1907     Vals.push_back(GetEncodedOrdering(
1908                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1909     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1910     break;
1911   case Instruction::AtomicRMW:
1912     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1913     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1914     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1915     Vals.push_back(GetEncodedRMWOperation(
1916                      cast<AtomicRMWInst>(I).getOperation()));
1917     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1918     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1919     Vals.push_back(GetEncodedSynchScope(
1920                      cast<AtomicRMWInst>(I).getSynchScope()));
1921     break;
1922   case Instruction::Fence:
1923     Code = bitc::FUNC_CODE_INST_FENCE;
1924     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1925     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1926     break;
1927   case Instruction::Call: {
1928     const CallInst &CI = cast<CallInst>(I);
1929     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1930     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1931
1932     Code = bitc::FUNC_CODE_INST_CALL;
1933
1934     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1935     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1936                    unsigned(CI.isMustTailCall()) << 14);
1937     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1938
1939     // Emit value #'s for the fixed parameters.
1940     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1941       // Check for labels (can happen with asm labels).
1942       if (FTy->getParamType(i)->isLabelTy())
1943         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1944       else
1945         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1946     }
1947
1948     // Emit type/value pairs for varargs params.
1949     if (FTy->isVarArg()) {
1950       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1951            i != e; ++i)
1952         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1953     }
1954     break;
1955   }
1956   case Instruction::VAArg:
1957     Code = bitc::FUNC_CODE_INST_VAARG;
1958     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1959     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1960     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1961     break;
1962   }
1963
1964   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1965   Vals.clear();
1966 }
1967
1968 // Emit names for globals/functions etc.
1969 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1970                                   const ValueEnumerator &VE,
1971                                   BitstreamWriter &Stream) {
1972   if (VST.empty()) return;
1973   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1974
1975   // FIXME: Set up the abbrev, we know how many values there are!
1976   // FIXME: We know if the type names can use 7-bit ascii.
1977   SmallVector<unsigned, 64> NameVals;
1978
1979   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1980        SI != SE; ++SI) {
1981
1982     const ValueName &Name = *SI;
1983
1984     // Figure out the encoding to use for the name.
1985     bool is7Bit = true;
1986     bool isChar6 = true;
1987     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1988          C != E; ++C) {
1989       if (isChar6)
1990         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1991       if ((unsigned char)*C & 128) {
1992         is7Bit = false;
1993         break;  // don't bother scanning the rest.
1994       }
1995     }
1996
1997     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1998
1999     // VST_ENTRY:   [valueid, namechar x N]
2000     // VST_BBENTRY: [bbid, namechar x N]
2001     unsigned Code;
2002     if (isa<BasicBlock>(SI->getValue())) {
2003       Code = bitc::VST_CODE_BBENTRY;
2004       if (isChar6)
2005         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2006     } else {
2007       Code = bitc::VST_CODE_ENTRY;
2008       if (isChar6)
2009         AbbrevToUse = VST_ENTRY_6_ABBREV;
2010       else if (is7Bit)
2011         AbbrevToUse = VST_ENTRY_7_ABBREV;
2012     }
2013
2014     NameVals.push_back(VE.getValueID(SI->getValue()));
2015     for (const char *P = Name.getKeyData(),
2016          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
2017       NameVals.push_back((unsigned char)*P);
2018
2019     // Emit the finished record.
2020     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2021     NameVals.clear();
2022   }
2023   Stream.ExitBlock();
2024 }
2025
2026 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
2027                          BitstreamWriter &Stream) {
2028   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2029   unsigned Code;
2030   if (isa<BasicBlock>(Order.V))
2031     Code = bitc::USELIST_CODE_BB;
2032   else
2033     Code = bitc::USELIST_CODE_DEFAULT;
2034
2035   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2036   Record.push_back(VE.getValueID(Order.V));
2037   Stream.EmitRecord(Code, Record);
2038 }
2039
2040 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
2041                               BitstreamWriter &Stream) {
2042   auto hasMore = [&]() {
2043     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2044   };
2045   if (!hasMore())
2046     // Nothing to do.
2047     return;
2048
2049   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2050   while (hasMore()) {
2051     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
2052     VE.UseListOrders.pop_back();
2053   }
2054   Stream.ExitBlock();
2055 }
2056
2057 /// WriteFunction - Emit a function body to the module stream.
2058 static void WriteFunction(const Function &F, ValueEnumerator &VE,
2059                           BitstreamWriter &Stream) {
2060   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2061   VE.incorporateFunction(F);
2062
2063   SmallVector<unsigned, 64> Vals;
2064
2065   // Emit the number of basic blocks, so the reader can create them ahead of
2066   // time.
2067   Vals.push_back(VE.getBasicBlocks().size());
2068   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2069   Vals.clear();
2070
2071   // If there are function-local constants, emit them now.
2072   unsigned CstStart, CstEnd;
2073   VE.getFunctionConstantRange(CstStart, CstEnd);
2074   WriteConstants(CstStart, CstEnd, VE, Stream, false);
2075
2076   // If there is function-local metadata, emit it now.
2077   WriteFunctionLocalMetadata(F, VE, Stream);
2078
2079   // Keep a running idea of what the instruction ID is.
2080   unsigned InstID = CstEnd;
2081
2082   bool NeedsMetadataAttachment = false;
2083
2084   DebugLoc LastDL;
2085
2086   // Finally, emit all the instructions, in order.
2087   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2088     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2089          I != E; ++I) {
2090       WriteInstruction(*I, InstID, VE, Stream, Vals);
2091
2092       if (!I->getType()->isVoidTy())
2093         ++InstID;
2094
2095       // If the instruction has metadata, write a metadata attachment later.
2096       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2097
2098       // If the instruction has a debug location, emit it.
2099       DebugLoc DL = I->getDebugLoc();
2100       if (DL.isUnknown()) {
2101         // nothing todo.
2102       } else if (DL == LastDL) {
2103         // Just repeat the same debug loc as last time.
2104         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
2105       } else {
2106         MDNode *Scope, *IA;
2107         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
2108         assert(Scope && "Expected valid scope");
2109
2110         Vals.push_back(DL.getLine());
2111         Vals.push_back(DL.getCol());
2112         Vals.push_back(VE.getMetadataOrNullID(Scope));
2113         Vals.push_back(VE.getMetadataOrNullID(IA));
2114         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
2115         Vals.clear();
2116
2117         LastDL = DL;
2118       }
2119     }
2120
2121   // Emit names for all the instructions etc.
2122   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
2123
2124   if (NeedsMetadataAttachment)
2125     WriteMetadataAttachment(F, VE, Stream);
2126   if (shouldPreserveBitcodeUseListOrder())
2127     WriteUseListBlock(&F, VE, Stream);
2128   VE.purgeFunction();
2129   Stream.ExitBlock();
2130 }
2131
2132 // Emit blockinfo, which defines the standard abbreviations etc.
2133 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
2134   // We only want to emit block info records for blocks that have multiple
2135   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
2136   // Other blocks can define their abbrevs inline.
2137   Stream.EnterBlockInfoBlock(2);
2138
2139   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
2140     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2141     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
2142     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2143     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2144     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2145     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2146                                    Abbv) != VST_ENTRY_8_ABBREV)
2147       llvm_unreachable("Unexpected abbrev ordering!");
2148   }
2149
2150   { // 7-bit fixed width VST_ENTRY strings.
2151     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2152     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2153     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2154     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2155     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2156     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2157                                    Abbv) != VST_ENTRY_7_ABBREV)
2158       llvm_unreachable("Unexpected abbrev ordering!");
2159   }
2160   { // 6-bit char6 VST_ENTRY strings.
2161     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2162     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
2163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2166     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2167                                    Abbv) != VST_ENTRY_6_ABBREV)
2168       llvm_unreachable("Unexpected abbrev ordering!");
2169   }
2170   { // 6-bit char6 VST_BBENTRY strings.
2171     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2172     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
2173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2174     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2176     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
2177                                    Abbv) != VST_BBENTRY_6_ABBREV)
2178       llvm_unreachable("Unexpected abbrev ordering!");
2179   }
2180
2181
2182
2183   { // SETTYPE abbrev for CONSTANTS_BLOCK.
2184     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2185     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
2186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
2187                               Log2_32_Ceil(VE.getTypes().size()+1)));
2188     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2189                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
2190       llvm_unreachable("Unexpected abbrev ordering!");
2191   }
2192
2193   { // INTEGER abbrev for CONSTANTS_BLOCK.
2194     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2195     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2196     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2197     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2198                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2199       llvm_unreachable("Unexpected abbrev ordering!");
2200   }
2201
2202   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2203     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2204     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2206     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2207                               Log2_32_Ceil(VE.getTypes().size()+1)));
2208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2209
2210     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2211                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2212       llvm_unreachable("Unexpected abbrev ordering!");
2213   }
2214   { // NULL abbrev for CONSTANTS_BLOCK.
2215     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2216     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2217     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2218                                    Abbv) != CONSTANTS_NULL_Abbrev)
2219       llvm_unreachable("Unexpected abbrev ordering!");
2220   }
2221
2222   // FIXME: This should only use space for first class types!
2223
2224   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2225     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2226     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2228     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2229     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2230     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2231                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2232       llvm_unreachable("Unexpected abbrev ordering!");
2233   }
2234   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2235     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2236     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2240     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2241                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2242       llvm_unreachable("Unexpected abbrev ordering!");
2243   }
2244   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2245     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2246     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2251     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2252                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2253       llvm_unreachable("Unexpected abbrev ordering!");
2254   }
2255   { // INST_CAST abbrev for FUNCTION_BLOCK.
2256     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2257     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2260                               Log2_32_Ceil(VE.getTypes().size()+1)));
2261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2262     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2263                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2264       llvm_unreachable("Unexpected abbrev ordering!");
2265   }
2266
2267   { // INST_RET abbrev for FUNCTION_BLOCK.
2268     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2269     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2270     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2271                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2272       llvm_unreachable("Unexpected abbrev ordering!");
2273   }
2274   { // INST_RET abbrev for FUNCTION_BLOCK.
2275     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2276     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2278     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2279                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2280       llvm_unreachable("Unexpected abbrev ordering!");
2281   }
2282   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2283     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2284     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2285     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2286                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2287       llvm_unreachable("Unexpected abbrev ordering!");
2288   }
2289
2290   Stream.ExitBlock();
2291 }
2292
2293 /// WriteModule - Emit the specified module to the bitstream.
2294 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2295   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2296
2297   SmallVector<unsigned, 1> Vals;
2298   unsigned CurVersion = 1;
2299   Vals.push_back(CurVersion);
2300   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2301
2302   // Analyze the module, enumerating globals, functions, etc.
2303   ValueEnumerator VE(*M);
2304
2305   // Emit blockinfo, which defines the standard abbreviations etc.
2306   WriteBlockInfo(VE, Stream);
2307
2308   // Emit information about attribute groups.
2309   WriteAttributeGroupTable(VE, Stream);
2310
2311   // Emit information about parameter attributes.
2312   WriteAttributeTable(VE, Stream);
2313
2314   // Emit information describing all of the types in the module.
2315   WriteTypeTable(VE, Stream);
2316
2317   writeComdats(VE, Stream);
2318
2319   // Emit top-level description of module, including target triple, inline asm,
2320   // descriptors for global variables, and function prototype info.
2321   WriteModuleInfo(M, VE, Stream);
2322
2323   // Emit constants.
2324   WriteModuleConstants(VE, Stream);
2325
2326   // Emit metadata.
2327   WriteModuleMetadata(M, VE, Stream);
2328
2329   // Emit metadata.
2330   WriteModuleMetadataStore(M, Stream);
2331
2332   // Emit names for globals/functions etc.
2333   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2334
2335   // Emit module-level use-lists.
2336   if (shouldPreserveBitcodeUseListOrder())
2337     WriteUseListBlock(nullptr, VE, Stream);
2338
2339   // Emit function bodies.
2340   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2341     if (!F->isDeclaration())
2342       WriteFunction(*F, VE, Stream);
2343
2344   Stream.ExitBlock();
2345 }
2346
2347 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2348 /// header and trailer to make it compatible with the system archiver.  To do
2349 /// this we emit the following header, and then emit a trailer that pads the
2350 /// file out to be a multiple of 16 bytes.
2351 ///
2352 /// struct bc_header {
2353 ///   uint32_t Magic;         // 0x0B17C0DE
2354 ///   uint32_t Version;       // Version, currently always 0.
2355 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2356 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2357 ///   uint32_t CPUType;       // CPU specifier.
2358 ///   ... potentially more later ...
2359 /// };
2360 enum {
2361   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2362   DarwinBCHeaderSize = 5*4
2363 };
2364
2365 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2366                                uint32_t &Position) {
2367   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2368   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2369   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2370   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2371   Position += 4;
2372 }
2373
2374 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2375                                          const Triple &TT) {
2376   unsigned CPUType = ~0U;
2377
2378   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2379   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2380   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2381   // specific constants here because they are implicitly part of the Darwin ABI.
2382   enum {
2383     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2384     DARWIN_CPU_TYPE_X86        = 7,
2385     DARWIN_CPU_TYPE_ARM        = 12,
2386     DARWIN_CPU_TYPE_POWERPC    = 18
2387   };
2388
2389   Triple::ArchType Arch = TT.getArch();
2390   if (Arch == Triple::x86_64)
2391     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2392   else if (Arch == Triple::x86)
2393     CPUType = DARWIN_CPU_TYPE_X86;
2394   else if (Arch == Triple::ppc)
2395     CPUType = DARWIN_CPU_TYPE_POWERPC;
2396   else if (Arch == Triple::ppc64)
2397     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2398   else if (Arch == Triple::arm || Arch == Triple::thumb)
2399     CPUType = DARWIN_CPU_TYPE_ARM;
2400
2401   // Traditional Bitcode starts after header.
2402   assert(Buffer.size() >= DarwinBCHeaderSize &&
2403          "Expected header size to be reserved");
2404   unsigned BCOffset = DarwinBCHeaderSize;
2405   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2406
2407   // Write the magic and version.
2408   unsigned Position = 0;
2409   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2410   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2411   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2412   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2413   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2414
2415   // If the file is not a multiple of 16 bytes, insert dummy padding.
2416   while (Buffer.size() & 15)
2417     Buffer.push_back(0);
2418 }
2419
2420 /// WriteBitcodeToFile - Write the specified module to the specified output
2421 /// stream.
2422 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2423   SmallVector<char, 0> Buffer;
2424   Buffer.reserve(256*1024);
2425
2426   // If this is darwin or another generic macho target, reserve space for the
2427   // header.
2428   Triple TT(M->getTargetTriple());
2429   if (TT.isOSDarwin())
2430     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2431
2432   // Emit the module into the buffer.
2433   {
2434     BitstreamWriter Stream(Buffer);
2435
2436     // Emit the file header.
2437     Stream.Emit((unsigned)'B', 8);
2438     Stream.Emit((unsigned)'C', 8);
2439     Stream.Emit(0x0, 4);
2440     Stream.Emit(0xC, 4);
2441     Stream.Emit(0xE, 4);
2442     Stream.Emit(0xD, 4);
2443
2444     // Emit the module.
2445     WriteModule(M, Stream);
2446   }
2447
2448   if (TT.isOSDarwin())
2449     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2450
2451   // Write the generated bitstream to "Out".
2452   Out.write((char*)&Buffer.front(), Buffer.size());
2453 }