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/DerivedTypes.h"
  21 #include "llvm/IR/InlineAsm.h"
  22 #include "llvm/IR/Instructions.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/IR/Operator.h"
  25 #include "llvm/IR/UseListOrder.h"
  26 #include "llvm/IR/ValueSymbolTable.h"
  27 #include "llvm/Support/CommandLine.h"
  28 #include "llvm/Support/ErrorHandling.h"
  29 #include "llvm/Support/MathExtras.h"
  30 #include "llvm/Support/Program.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include <cctype>
  33 #include <map>
  34 using namespace llvm;
  35
  36 /// These are manifest constants used by the bitcode writer. They do not need to
  37 /// be kept in sync with the reader, but need to be consistent within this file.
  38 enum {
  39   // VALUE_SYMTAB_BLOCK abbrev id's.
  40   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  41   VST_ENTRY_7_ABBREV,
  42   VST_ENTRY_6_ABBREV,
  43   VST_BBENTRY_6_ABBREV,
  44
  45   // CONSTANTS_BLOCK abbrev id's.
  46   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  47   CONSTANTS_INTEGER_ABBREV,
  48   CONSTANTS_CE_CAST_Abbrev,
  49   CONSTANTS_NULL_Abbrev,
  50
  51   // FUNCTION_BLOCK abbrev id's.
  52   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  53   FUNCTION_INST_BINOP_ABBREV,
  54   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  55   FUNCTION_INST_CAST_ABBREV,
  56   FUNCTION_INST_RET_VOID_ABBREV,
  57   FUNCTION_INST_RET_VAL_ABBREV,
  58   FUNCTION_INST_UNREACHABLE_ABBREV
  59 };
  60
  61 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  62   switch (Opcode) {
  63   default: llvm_unreachable("Unknown cast instruction!");
  64   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  65   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  66   case Instruction::SExt    : return bitc::CAST_SEXT;
  67   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  68   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  69   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  70   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  71   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  72   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  73   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  74   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  75   case Instruction::BitCast : return bitc::CAST_BITCAST;
  76   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  77   }
  78 }
  79
  80 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  81   switch (Opcode) {
  82   default: llvm_unreachable("Unknown binary instruction!");
  83   case Instruction::Add:
  84   case Instruction::FAdd: return bitc::BINOP_ADD;
  85   case Instruction::Sub:
  86   case Instruction::FSub: return bitc::BINOP_SUB;
  87   case Instruction::Mul:
  88   case Instruction::FMul: return bitc::BINOP_MUL;
  89   case Instruction::UDiv: return bitc::BINOP_UDIV;
  90   case Instruction::FDiv:
  91   case Instruction::SDiv: return bitc::BINOP_SDIV;
  92   case Instruction::URem: return bitc::BINOP_UREM;
  93   case Instruction::FRem:
  94   case Instruction::SRem: return bitc::BINOP_SREM;
  95   case Instruction::Shl:  return bitc::BINOP_SHL;
  96   case Instruction::LShr: return bitc::BINOP_LSHR;
  97   case Instruction::AShr: return bitc::BINOP_ASHR;
  98   case Instruction::And:  return bitc::BINOP_AND;
  99   case Instruction::Or:   return bitc::BINOP_OR;
 100   case Instruction::Xor:  return bitc::BINOP_XOR;
 101   }
 102 }
 103
 104 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 105   switch (Op) {
 106   default: llvm_unreachable("Unknown RMW operation!");
 107   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 108   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 109   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 110   case AtomicRMWInst::And: return bitc::RMW_AND;
 111   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 112   case AtomicRMWInst::Or: return bitc::RMW_OR;
 113   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 114   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 115   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 116   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 117   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 118   }
 119 }
 120
 121 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 122   switch (Ordering) {
 123   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 124   case Unordered: return bitc::ORDERING_UNORDERED;
 125   case Monotonic: return bitc::ORDERING_MONOTONIC;
 126   case Acquire: return bitc::ORDERING_ACQUIRE;
 127   case Release: return bitc::ORDERING_RELEASE;
 128   case AcquireRelease: return bitc::ORDERING_ACQREL;
 129   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 130   }
 131   llvm_unreachable("Invalid ordering");
 132 }
 133
 134 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 135   switch (SynchScope) {
 136   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 137   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 138   }
 139   llvm_unreachable("Invalid synch scope");
 140 }
 141
 142 static void WriteStringRecord(unsigned Code, StringRef Str,
 143                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 144   SmallVector<unsigned, 64> Vals;
 145
 146   // Code: [strchar x N]
 147   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 148     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 149       AbbrevToUse = 0;
 150     Vals.push_back(Str[i]);
 151   }
 152
 153   // Emit the finished record.
 154   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 155 }
 156
 157 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 158   switch (Kind) {
 159   case Attribute::Alignment:
 160     return bitc::ATTR_KIND_ALIGNMENT;
 161   case Attribute::AlwaysInline:
 162     return bitc::ATTR_KIND_ALWAYS_INLINE;
 163   case Attribute::Builtin:
 164     return bitc::ATTR_KIND_BUILTIN;
 165   case Attribute::ByVal:
 166     return bitc::ATTR_KIND_BY_VAL;
 167   case Attribute::InAlloca:
 168     return bitc::ATTR_KIND_IN_ALLOCA;
 169   case Attribute::Cold:
 170     return bitc::ATTR_KIND_COLD;
 171   case Attribute::InlineHint:
 172     return bitc::ATTR_KIND_INLINE_HINT;
 173   case Attribute::InReg:
 174     return bitc::ATTR_KIND_IN_REG;
 175   case Attribute::JumpTable:
 176     return bitc::ATTR_KIND_JUMP_TABLE;
 177   case Attribute::MinSize:
 178     return bitc::ATTR_KIND_MIN_SIZE;
 179   case Attribute::Naked:
 180     return bitc::ATTR_KIND_NAKED;
 181   case Attribute::Nest:
 182     return bitc::ATTR_KIND_NEST;
 183   case Attribute::NoAlias:
 184     return bitc::ATTR_KIND_NO_ALIAS;
 185   case Attribute::NoBuiltin:
 186     return bitc::ATTR_KIND_NO_BUILTIN;
 187   case Attribute::NoCapture:
 188     return bitc::ATTR_KIND_NO_CAPTURE;
 189   case Attribute::NoDuplicate:
 190     return bitc::ATTR_KIND_NO_DUPLICATE;
 191   case Attribute::NoImplicitFloat:
 192     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 193   case Attribute::NoInline:
 194     return bitc::ATTR_KIND_NO_INLINE;
 195   case Attribute::NonLazyBind:
 196     return bitc::ATTR_KIND_NON_LAZY_BIND;
 197   case Attribute::NonNull:
 198     return bitc::ATTR_KIND_NON_NULL;
 199   case Attribute::Dereferenceable:
 200     return bitc::ATTR_KIND_DEREFERENCEABLE;
 201   case Attribute::NoRedZone:
 202     return bitc::ATTR_KIND_NO_RED_ZONE;
 203   case Attribute::NoReturn:
 204     return bitc::ATTR_KIND_NO_RETURN;
 205   case Attribute::NoUnwind:
 206     return bitc::ATTR_KIND_NO_UNWIND;
 207   case Attribute::OptimizeForSize:
 208     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 209   case Attribute::OptimizeNone:
 210     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 211   case Attribute::ReadNone:
 212     return bitc::ATTR_KIND_READ_NONE;
 213   case Attribute::ReadOnly:
 214     return bitc::ATTR_KIND_READ_ONLY;
 215   case Attribute::Returned:
 216     return bitc::ATTR_KIND_RETURNED;
 217   case Attribute::ReturnsTwice:
 218     return bitc::ATTR_KIND_RETURNS_TWICE;
 219   case Attribute::SExt:
 220     return bitc::ATTR_KIND_S_EXT;
 221   case Attribute::StackAlignment:
 222     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 223   case Attribute::StackProtect:
 224     return bitc::ATTR_KIND_STACK_PROTECT;
 225   case Attribute::StackProtectReq:
 226     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 227   case Attribute::StackProtectStrong:
 228     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 229   case Attribute::StructRet:
 230     return bitc::ATTR_KIND_STRUCT_RET;
 231   case Attribute::SanitizeAddress:
 232     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 233   case Attribute::SanitizeThread:
 234     return bitc::ATTR_KIND_SANITIZE_THREAD;
 235   case Attribute::SanitizeMemory:
 236     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 237   case Attribute::UWTable:
 238     return bitc::ATTR_KIND_UW_TABLE;
 239   case Attribute::ZExt:
 240     return bitc::ATTR_KIND_Z_EXT;
 241   case Attribute::EndAttrKinds:
 242     llvm_unreachable("Can not encode end-attribute kinds marker.");
 243   case Attribute::None:
 244     llvm_unreachable("Can not encode none-attribute.");
 245   }
 246
 247   llvm_unreachable("Trying to encode unknown attribute");
 248 }
 249
 250 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 251                                      BitstreamWriter &Stream) {
 252   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 253   if (AttrGrps.empty()) return;
 254
 255   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 256
 257   SmallVector<uint64_t, 64> Record;
 258   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 259     AttributeSet AS = AttrGrps[i];
 260     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 261       AttributeSet A = AS.getSlotAttributes(i);
 262
 263       Record.push_back(VE.getAttributeGroupID(A));
 264       Record.push_back(AS.getSlotIndex(i));
 265
 266       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 267            I != E; ++I) {
 268         Attribute Attr = *I;
 269         if (Attr.isEnumAttribute()) {
 270           Record.push_back(0);
 271           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 272         } else if (Attr.isIntAttribute()) {
 273           Record.push_back(1);
 274           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 275           Record.push_back(Attr.getValueAsInt());
 276         } else {
 277           StringRef Kind = Attr.getKindAsString();
 278           StringRef Val = Attr.getValueAsString();
 279
 280           Record.push_back(Val.empty() ? 3 : 4);
 281           Record.append(Kind.begin(), Kind.end());
 282           Record.push_back(0);
 283           if (!Val.empty()) {
 284             Record.append(Val.begin(), Val.end());
 285             Record.push_back(0);
 286           }
 287         }
 288       }
 289
 290       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 291       Record.clear();
 292     }
 293   }
 294
 295   Stream.ExitBlock();
 296 }
 297
 298 static void WriteAttributeTable(const ValueEnumerator &VE,
 299                                 BitstreamWriter &Stream) {
 300   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 301   if (Attrs.empty()) return;
 302
 303   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 304
 305   SmallVector<uint64_t, 64> Record;
 306   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 307     const AttributeSet &A = Attrs[i];
 308     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 309       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 310
 311     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 312     Record.clear();
 313   }
 314
 315   Stream.ExitBlock();
 316 }
 317
 318 /// WriteTypeTable - Write out the type table for a module.
 319 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 320   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 321
 322   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 323   SmallVector<uint64_t, 64> TypeVals;
 324
 325   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 326
 327   // Abbrev for TYPE_CODE_POINTER.
 328   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 329   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 330   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 331   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 332   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 333
 334   // Abbrev for TYPE_CODE_FUNCTION.
 335   Abbv = new BitCodeAbbrev();
 336   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 337   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 339   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 340
 341   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 342
 343   // Abbrev for TYPE_CODE_STRUCT_ANON.
 344   Abbv = new BitCodeAbbrev();
 345   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 346   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 348   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 349
 350   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 351
 352   // Abbrev for TYPE_CODE_STRUCT_NAME.
 353   Abbv = new BitCodeAbbrev();
 354   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 357   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 358
 359   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 360   Abbv = new BitCodeAbbrev();
 361   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 365
 366   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 367
 368   // Abbrev for TYPE_CODE_ARRAY.
 369   Abbv = new BitCodeAbbrev();
 370   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 373
 374   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 375
 376   // Emit an entry count so the reader can reserve space.
 377   TypeVals.push_back(TypeList.size());
 378   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 379   TypeVals.clear();
 380
 381   // Loop over all of the types, emitting each in turn.
 382   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 383     Type *T = TypeList[i];
 384     int AbbrevToUse = 0;
 385     unsigned Code = 0;
 386
 387     switch (T->getTypeID()) {
 388     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 389     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 390     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 391     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 392     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 393     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 394     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 395     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 396     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 397     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 398     case Type::IntegerTyID:
 399       // INTEGER: [width]
 400       Code = bitc::TYPE_CODE_INTEGER;
 401       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 402       break;
 403     case Type::PointerTyID: {
 404       PointerType *PTy = cast<PointerType>(T);
 405       // POINTER: [pointee type, address space]
 406       Code = bitc::TYPE_CODE_POINTER;
 407       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 408       unsigned AddressSpace = PTy->getAddressSpace();
 409       TypeVals.push_back(AddressSpace);
 410       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 411       break;
 412     }
 413     case Type::FunctionTyID: {
 414       FunctionType *FT = cast<FunctionType>(T);
 415       // FUNCTION: [isvararg, retty, paramty x N]
 416       Code = bitc::TYPE_CODE_FUNCTION;
 417       TypeVals.push_back(FT->isVarArg());
 418       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 419       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 420         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 421       AbbrevToUse = FunctionAbbrev;
 422       break;
 423     }
 424     case Type::StructTyID: {
 425       StructType *ST = cast<StructType>(T);
 426       // STRUCT: [ispacked, eltty x N]
 427       TypeVals.push_back(ST->isPacked());
 428       // Output all of the element types.
 429       for (StructType::element_iterator I = ST->element_begin(),
 430            E = ST->element_end(); I != E; ++I)
 431         TypeVals.push_back(VE.getTypeID(*I));
 432
 433       if (ST->isLiteral()) {
 434         Code = bitc::TYPE_CODE_STRUCT_ANON;
 435         AbbrevToUse = StructAnonAbbrev;
 436       } else {
 437         if (ST->isOpaque()) {
 438           Code = bitc::TYPE_CODE_OPAQUE;
 439         } else {
 440           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 441           AbbrevToUse = StructNamedAbbrev;
 442         }
 443
 444         // Emit the name if it is present.
 445         if (!ST->getName().empty())
 446           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 447                             StructNameAbbrev, Stream);
 448       }
 449       break;
 450     }
 451     case Type::ArrayTyID: {
 452       ArrayType *AT = cast<ArrayType>(T);
 453       // ARRAY: [numelts, eltty]
 454       Code = bitc::TYPE_CODE_ARRAY;
 455       TypeVals.push_back(AT->getNumElements());
 456       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 457       AbbrevToUse = ArrayAbbrev;
 458       break;
 459     }
 460     case Type::VectorTyID: {
 461       VectorType *VT = cast<VectorType>(T);
 462       // VECTOR [numelts, eltty]
 463       Code = bitc::TYPE_CODE_VECTOR;
 464       TypeVals.push_back(VT->getNumElements());
 465       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 466       break;
 467     }
 468     }
 469
 470     // Emit the finished record.
 471     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 472     TypeVals.clear();
 473   }
 474
 475   Stream.ExitBlock();
 476 }
 477
 478 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 479   switch (GV.getLinkage()) {
 480   case GlobalValue::ExternalLinkage:                 return 0;
 481   case GlobalValue::WeakAnyLinkage:                  return 1;
 482   case GlobalValue::AppendingLinkage:                return 2;
 483   case GlobalValue::InternalLinkage:                 return 3;
 484   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 485   case GlobalValue::ExternalWeakLinkage:             return 7;
 486   case GlobalValue::CommonLinkage:                   return 8;
 487   case GlobalValue::PrivateLinkage:                  return 9;
 488   case GlobalValue::WeakODRLinkage:                  return 10;
 489   case GlobalValue::LinkOnceODRLinkage:              return 11;
 490   case GlobalValue::AvailableExternallyLinkage:      return 12;
 491   }
 492   llvm_unreachable("Invalid linkage");
 493 }
 494
 495 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 496   switch (GV.getVisibility()) {
 497   case GlobalValue::DefaultVisibility:   return 0;
 498   case GlobalValue::HiddenVisibility:    return 1;
 499   case GlobalValue::ProtectedVisibility: return 2;
 500   }
 501   llvm_unreachable("Invalid visibility");
 502 }
 503
 504 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 505   switch (GV.getDLLStorageClass()) {
 506   case GlobalValue::DefaultStorageClass:   return 0;
 507   case GlobalValue::DLLImportStorageClass: return 1;
 508   case GlobalValue::DLLExportStorageClass: return 2;
 509   }
 510   llvm_unreachable("Invalid DLL storage class");
 511 }
 512
 513 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 514   switch (GV.getThreadLocalMode()) {
 515     case GlobalVariable::NotThreadLocal:         return 0;
 516     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 517     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 518     case GlobalVariable::InitialExecTLSModel:    return 3;
 519     case GlobalVariable::LocalExecTLSModel:      return 4;
 520   }
 521   llvm_unreachable("Invalid TLS model");
 522 }
 523
 524 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 525   switch (C.getSelectionKind()) {
 526   case Comdat::Any:
 527     return bitc::COMDAT_SELECTION_KIND_ANY;
 528   case Comdat::ExactMatch:
 529     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 530   case Comdat::Largest:
 531     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 532   case Comdat::NoDuplicates:
 533     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 534   case Comdat::SameSize:
 535     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 536   }
 537   llvm_unreachable("Invalid selection kind");
 538 }
 539
 540 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 541   SmallVector<uint8_t, 64> Vals;
 542   for (const Comdat *C : VE.getComdats()) {
 543     // COMDAT: [selection_kind, name]
 544     Vals.push_back(getEncodedComdatSelectionKind(*C));
 545     Vals.push_back(C->getName().size());
 546     for (char Chr : C->getName())
 547       Vals.push_back((unsigned char)Chr);
 548     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 549     Vals.clear();
 550   }
 551 }
 552
 553 // Emit top-level description of module, including target triple, inline asm,
 554 // descriptors for global variables, and function prototype info.
 555 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 556                             BitstreamWriter &Stream) {
 557   // Emit various pieces of data attached to a module.
 558   if (!M->getTargetTriple().empty())
 559     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 560                       0/*TODO*/, Stream);
 561   const std::string &DL = M->getDataLayoutStr();
 562   if (!DL.empty())
 563     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 564   if (!M->getModuleInlineAsm().empty())
 565     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 566                       0/*TODO*/, Stream);
 567
 568   // Emit information about sections and GC, computing how many there are. Also
 569   // compute the maximum alignment value.
 570   std::map<std::string, unsigned> SectionMap;
 571   std::map<std::string, unsigned> GCMap;
 572   unsigned MaxAlignment = 0;
 573   unsigned MaxGlobalType = 0;
 574   for (const GlobalValue &GV : M->globals()) {
 575     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 576     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 577     if (GV.hasSection()) {
 578       // Give section names unique ID's.
 579       unsigned &Entry = SectionMap[GV.getSection()];
 580       if (!Entry) {
 581         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 582                           0/*TODO*/, Stream);
 583         Entry = SectionMap.size();
 584       }
 585     }
 586   }
 587   for (const Function &F : *M) {
 588     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 589     if (F.hasSection()) {
 590       // Give section names unique ID's.
 591       unsigned &Entry = SectionMap[F.getSection()];
 592       if (!Entry) {
 593         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 594                           0/*TODO*/, Stream);
 595         Entry = SectionMap.size();
 596       }
 597     }
 598     if (F.hasGC()) {
 599       // Same for GC names.
 600       unsigned &Entry = GCMap[F.getGC()];
 601       if (!Entry) {
 602         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 603                           0/*TODO*/, Stream);
 604         Entry = GCMap.size();
 605       }
 606     }
 607   }
 608
 609   // Emit abbrev for globals, now that we know # sections and max alignment.
 610   unsigned SimpleGVarAbbrev = 0;
 611   if (!M->global_empty()) {
 612     // Add an abbrev for common globals with no visibility or thread localness.
 613     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 614     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 615     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 616                               Log2_32_Ceil(MaxGlobalType+1)));
 617     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 618     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 619     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 620     if (MaxAlignment == 0)                                      // Alignment.
 621       Abbv->Add(BitCodeAbbrevOp(0));
 622     else {
 623       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 624       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 625                                Log2_32_Ceil(MaxEncAlignment+1)));
 626     }
 627     if (SectionMap.empty())                                    // Section.
 628       Abbv->Add(BitCodeAbbrevOp(0));
 629     else
 630       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 631                                Log2_32_Ceil(SectionMap.size()+1)));
 632     // Don't bother emitting vis + thread local.
 633     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 634   }
 635
 636   // Emit the global variable information.
 637   SmallVector<unsigned, 64> Vals;
 638   for (const GlobalVariable &GV : M->globals()) {
 639     unsigned AbbrevToUse = 0;
 640
 641     // GLOBALVAR: [type, isconst, initid,
 642     //             linkage, alignment, section, visibility, threadlocal,
 643     //             unnamed_addr, externally_initialized, dllstorageclass]
 644     Vals.push_back(VE.getTypeID(GV.getType()));
 645     Vals.push_back(GV.isConstant());
 646     Vals.push_back(GV.isDeclaration() ? 0 :
 647                    (VE.getValueID(GV.getInitializer()) + 1));
 648     Vals.push_back(getEncodedLinkage(GV));
 649     Vals.push_back(Log2_32(GV.getAlignment())+1);
 650     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 651     if (GV.isThreadLocal() ||
 652         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 653         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 654         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 655         GV.hasComdat()) {
 656       Vals.push_back(getEncodedVisibility(GV));
 657       Vals.push_back(getEncodedThreadLocalMode(GV));
 658       Vals.push_back(GV.hasUnnamedAddr());
 659       Vals.push_back(GV.isExternallyInitialized());
 660       Vals.push_back(getEncodedDLLStorageClass(GV));
 661       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 662     } else {
 663       AbbrevToUse = SimpleGVarAbbrev;
 664     }
 665
 666     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 667     Vals.clear();
 668   }
 669
 670   // Emit the function proto information.
 671   for (const Function &F : *M) {
 672     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 673     //             section, visibility, gc, unnamed_addr, prefix]
 674     Vals.push_back(VE.getTypeID(F.getType()));
 675     Vals.push_back(F.getCallingConv());
 676     Vals.push_back(F.isDeclaration());
 677     Vals.push_back(getEncodedLinkage(F));
 678     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 679     Vals.push_back(Log2_32(F.getAlignment())+1);
 680     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 681     Vals.push_back(getEncodedVisibility(F));
 682     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 683     Vals.push_back(F.hasUnnamedAddr());
 684     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 685                                       : 0);
 686     Vals.push_back(getEncodedDLLStorageClass(F));
 687     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 688
 689     unsigned AbbrevToUse = 0;
 690     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 691     Vals.clear();
 692   }
 693
 694   // Emit the alias information.
 695   for (const GlobalAlias &A : M->aliases()) {
 696     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 697     Vals.push_back(VE.getTypeID(A.getType()));
 698     Vals.push_back(VE.getValueID(A.getAliasee()));
 699     Vals.push_back(getEncodedLinkage(A));
 700     Vals.push_back(getEncodedVisibility(A));
 701     Vals.push_back(getEncodedDLLStorageClass(A));
 702     Vals.push_back(getEncodedThreadLocalMode(A));
 703     Vals.push_back(A.hasUnnamedAddr());
 704     unsigned AbbrevToUse = 0;
 705     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 706     Vals.clear();
 707   }
 708 }
 709
 710 static uint64_t GetOptimizationFlags(const Value *V) {
 711   uint64_t Flags = 0;
 712
 713   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 714     if (OBO->hasNoSignedWrap())
 715       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 716     if (OBO->hasNoUnsignedWrap())
 717       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 718   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 719     if (PEO->isExact())
 720       Flags |= 1 << bitc::PEO_EXACT;
 721   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 722     if (FPMO->hasUnsafeAlgebra())
 723       Flags |= FastMathFlags::UnsafeAlgebra;
 724     if (FPMO->hasNoNaNs())
 725       Flags |= FastMathFlags::NoNaNs;
 726     if (FPMO->hasNoInfs())
 727       Flags |= FastMathFlags::NoInfs;
 728     if (FPMO->hasNoSignedZeros())
 729       Flags |= FastMathFlags::NoSignedZeros;
 730     if (FPMO->hasAllowReciprocal())
 731       Flags |= FastMathFlags::AllowReciprocal;
 732   }
 733
 734   return Flags;
 735 }
 736
 737 static void WriteMDNode(const MDNode *N,
 738                         const ValueEnumerator &VE,
 739                         BitstreamWriter &Stream,
 740                         SmallVectorImpl<uint64_t> &Record) {
 741   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 742     if (N->getOperand(i)) {
 743       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 744       Record.push_back(VE.getValueID(N->getOperand(i)));
 745     } else {
 746       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 747       Record.push_back(0);
 748     }
 749   }
 750   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 751                                            bitc::METADATA_NODE;
 752   Stream.EmitRecord(MDCode, Record, 0);
 753   Record.clear();
 754 }
 755
 756 static void WriteModuleMetadata(const Module *M,
 757                                 const ValueEnumerator &VE,
 758                                 BitstreamWriter &Stream) {
 759   const auto &Vals = VE.getMDValues();
 760   bool StartedMetadataBlock = false;
 761   unsigned MDSAbbrev = 0;
 762   SmallVector<uint64_t, 64> Record;
 763   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 764
 765     if (const MDNode *N = dyn_cast<MDNode>(Vals[i])) {
 766       if (!N->isFunctionLocal() || !N->getFunction()) {
 767         if (!StartedMetadataBlock) {
 768           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 769           StartedMetadataBlock = true;
 770         }
 771         WriteMDNode(N, VE, Stream, Record);
 772       }
 773     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i])) {
 774       if (!StartedMetadataBlock)  {
 775         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 776
 777         // Abbrev for METADATA_STRING.
 778         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 779         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 780         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 781         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 782         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 783         StartedMetadataBlock = true;
 784       }
 785
 786       // Code: [strchar x N]
 787       Record.append(MDS->begin(), MDS->end());
 788
 789       // Emit the finished record.
 790       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 791       Record.clear();
 792     }
 793   }
 794
 795   // Write named metadata.
 796   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 797        E = M->named_metadata_end(); I != E; ++I) {
 798     const NamedMDNode *NMD = I;
 799     if (!StartedMetadataBlock)  {
 800       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 801       StartedMetadataBlock = true;
 802     }
 803
 804     // Write name.
 805     StringRef Str = NMD->getName();
 806     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 807       Record.push_back(Str[i]);
 808     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 809     Record.clear();
 810
 811     // Write named metadata operands.
 812     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 813       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 814     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 815     Record.clear();
 816   }
 817
 818   if (StartedMetadataBlock)
 819     Stream.ExitBlock();
 820 }
 821
 822 static void WriteFunctionLocalMetadata(const Function &F,
 823                                        const ValueEnumerator &VE,
 824                                        BitstreamWriter &Stream) {
 825   bool StartedMetadataBlock = false;
 826   SmallVector<uint64_t, 64> Record;
 827   const SmallVectorImpl<const MDNode *> &Vals = VE.getFunctionLocalMDValues();
 828   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 829     if (const MDNode *N = Vals[i])
 830       if (N->isFunctionLocal() && N->getFunction() == &F) {
 831         if (!StartedMetadataBlock) {
 832           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 833           StartedMetadataBlock = true;
 834         }
 835         WriteMDNode(N, VE, Stream, Record);
 836       }
 837
 838   if (StartedMetadataBlock)
 839     Stream.ExitBlock();
 840 }
 841
 842 static void WriteMetadataAttachment(const Function &F,
 843                                     const ValueEnumerator &VE,
 844                                     BitstreamWriter &Stream) {
 845   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 846
 847   SmallVector<uint64_t, 64> Record;
 848
 849   // Write metadata attachments
 850   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 851   SmallVector<std::pair<unsigned, Value *>, 4> MDs;
 852
 853   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 854     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 855          I != E; ++I) {
 856       MDs.clear();
 857       I->getAllMetadataOtherThanDebugLoc(MDs);
 858
 859       // If no metadata, ignore instruction.
 860       if (MDs.empty()) continue;
 861
 862       Record.push_back(VE.getInstructionID(I));
 863
 864       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 865         Record.push_back(MDs[i].first);
 866         Record.push_back(VE.getValueID(MDs[i].second));
 867       }
 868       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 869       Record.clear();
 870     }
 871
 872   Stream.ExitBlock();
 873 }
 874
 875 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 876   SmallVector<uint64_t, 64> Record;
 877
 878   // Write metadata kinds
 879   // METADATA_KIND - [n x [id, name]]
 880   SmallVector<StringRef, 8> Names;
 881   M->getMDKindNames(Names);
 882
 883   if (Names.empty()) return;
 884
 885   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 886
 887   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 888     Record.push_back(MDKindID);
 889     StringRef KName = Names[MDKindID];
 890     Record.append(KName.begin(), KName.end());
 891
 892     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 893     Record.clear();
 894   }
 895
 896   Stream.ExitBlock();
 897 }
 898
 899 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 900   if ((int64_t)V >= 0)
 901     Vals.push_back(V << 1);
 902   else
 903     Vals.push_back((-V << 1) | 1);
 904 }
 905
 906 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 907                            const ValueEnumerator &VE,
 908                            BitstreamWriter &Stream, bool isGlobal) {
 909   if (FirstVal == LastVal) return;
 910
 911   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 912
 913   unsigned AggregateAbbrev = 0;
 914   unsigned String8Abbrev = 0;
 915   unsigned CString7Abbrev = 0;
 916   unsigned CString6Abbrev = 0;
 917   // If this is a constant pool for the module, emit module-specific abbrevs.
 918   if (isGlobal) {
 919     // Abbrev for CST_CODE_AGGREGATE.
 920     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 921     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 922     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 923     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 924     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 925
 926     // Abbrev for CST_CODE_STRING.
 927     Abbv = new BitCodeAbbrev();
 928     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 930     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 931     String8Abbrev = Stream.EmitAbbrev(Abbv);
 932     // Abbrev for CST_CODE_CSTRING.
 933     Abbv = new BitCodeAbbrev();
 934     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 935     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 936     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 937     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 938     // Abbrev for CST_CODE_CSTRING.
 939     Abbv = new BitCodeAbbrev();
 940     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 941     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 942     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 943     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 944   }
 945
 946   SmallVector<uint64_t, 64> Record;
 947
 948   const ValueEnumerator::ValueList &Vals = VE.getValues();
 949   Type *LastTy = nullptr;
 950   for (unsigned i = FirstVal; i != LastVal; ++i) {
 951     const Value *V = Vals[i].first;
 952     // If we need to switch types, do so now.
 953     if (V->getType() != LastTy) {
 954       LastTy = V->getType();
 955       Record.push_back(VE.getTypeID(LastTy));
 956       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 957                         CONSTANTS_SETTYPE_ABBREV);
 958       Record.clear();
 959     }
 960
 961     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 962       Record.push_back(unsigned(IA->hasSideEffects()) |
 963                        unsigned(IA->isAlignStack()) << 1 |
 964                        unsigned(IA->getDialect()&1) << 2);
 965
 966       // Add the asm string.
 967       const std::string &AsmStr = IA->getAsmString();
 968       Record.push_back(AsmStr.size());
 969       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 970         Record.push_back(AsmStr[i]);
 971
 972       // Add the constraint string.
 973       const std::string &ConstraintStr = IA->getConstraintString();
 974       Record.push_back(ConstraintStr.size());
 975       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 976         Record.push_back(ConstraintStr[i]);
 977       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 978       Record.clear();
 979       continue;
 980     }
 981     const Constant *C = cast<Constant>(V);
 982     unsigned Code = -1U;
 983     unsigned AbbrevToUse = 0;
 984     if (C->isNullValue()) {
 985       Code = bitc::CST_CODE_NULL;
 986     } else if (isa<UndefValue>(C)) {
 987       Code = bitc::CST_CODE_UNDEF;
 988     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 989       if (IV->getBitWidth() <= 64) {
 990         uint64_t V = IV->getSExtValue();
 991         emitSignedInt64(Record, V);
 992         Code = bitc::CST_CODE_INTEGER;
 993         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 994       } else {                             // Wide integers, > 64 bits in size.
 995         // We have an arbitrary precision integer value to write whose
 996         // bit width is > 64. However, in canonical unsigned integer
 997         // format it is likely that the high bits are going to be zero.
 998         // So, we only write the number of active words.
 999         unsigned NWords = IV->getValue().getActiveWords();
1000         const uint64_t *RawWords = IV->getValue().getRawData();
1001         for (unsigned i = 0; i != NWords; ++i) {
1002           emitSignedInt64(Record, RawWords[i]);
1003         }
1004         Code = bitc::CST_CODE_WIDE_INTEGER;
1005       }
1006     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1007       Code = bitc::CST_CODE_FLOAT;
1008       Type *Ty = CFP->getType();
1009       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1010         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1011       } else if (Ty->isX86_FP80Ty()) {
1012         // api needed to prevent premature destruction
1013         // bits are not in the same order as a normal i80 APInt, compensate.
1014         APInt api = CFP->getValueAPF().bitcastToAPInt();
1015         const uint64_t *p = api.getRawData();
1016         Record.push_back((p[1] << 48) | (p[0] >> 16));
1017         Record.push_back(p[0] & 0xffffLL);
1018       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1019         APInt api = CFP->getValueAPF().bitcastToAPInt();
1020         const uint64_t *p = api.getRawData();
1021         Record.push_back(p[0]);
1022         Record.push_back(p[1]);
1023       } else {
1024         assert (0 && "Unknown FP type!");
1025       }
1026     } else if (isa<ConstantDataSequential>(C) &&
1027                cast<ConstantDataSequential>(C)->isString()) {
1028       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1029       // Emit constant strings specially.
1030       unsigned NumElts = Str->getNumElements();
1031       // If this is a null-terminated string, use the denser CSTRING encoding.
1032       if (Str->isCString()) {
1033         Code = bitc::CST_CODE_CSTRING;
1034         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1035       } else {
1036         Code = bitc::CST_CODE_STRING;
1037         AbbrevToUse = String8Abbrev;
1038       }
1039       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1040       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1041       for (unsigned i = 0; i != NumElts; ++i) {
1042         unsigned char V = Str->getElementAsInteger(i);
1043         Record.push_back(V);
1044         isCStr7 &= (V & 128) == 0;
1045         if (isCStrChar6)
1046           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1047       }
1048
1049       if (isCStrChar6)
1050         AbbrevToUse = CString6Abbrev;
1051       else if (isCStr7)
1052         AbbrevToUse = CString7Abbrev;
1053     } else if (const ConstantDataSequential *CDS =
1054                   dyn_cast<ConstantDataSequential>(C)) {
1055       Code = bitc::CST_CODE_DATA;
1056       Type *EltTy = CDS->getType()->getElementType();
1057       if (isa<IntegerType>(EltTy)) {
1058         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1059           Record.push_back(CDS->getElementAsInteger(i));
1060       } else if (EltTy->isFloatTy()) {
1061         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1062           union { float F; uint32_t I; };
1063           F = CDS->getElementAsFloat(i);
1064           Record.push_back(I);
1065         }
1066       } else {
1067         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1068         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1069           union { double F; uint64_t I; };
1070           F = CDS->getElementAsDouble(i);
1071           Record.push_back(I);
1072         }
1073       }
1074     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1075                isa<ConstantVector>(C)) {
1076       Code = bitc::CST_CODE_AGGREGATE;
1077       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1078         Record.push_back(VE.getValueID(C->getOperand(i)));
1079       AbbrevToUse = AggregateAbbrev;
1080     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1081       switch (CE->getOpcode()) {
1082       default:
1083         if (Instruction::isCast(CE->getOpcode())) {
1084           Code = bitc::CST_CODE_CE_CAST;
1085           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1086           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1087           Record.push_back(VE.getValueID(C->getOperand(0)));
1088           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1089         } else {
1090           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1091           Code = bitc::CST_CODE_CE_BINOP;
1092           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1093           Record.push_back(VE.getValueID(C->getOperand(0)));
1094           Record.push_back(VE.getValueID(C->getOperand(1)));
1095           uint64_t Flags = GetOptimizationFlags(CE);
1096           if (Flags != 0)
1097             Record.push_back(Flags);
1098         }
1099         break;
1100       case Instruction::GetElementPtr:
1101         Code = bitc::CST_CODE_CE_GEP;
1102         if (cast<GEPOperator>(C)->isInBounds())
1103           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1104         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1105           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1106           Record.push_back(VE.getValueID(C->getOperand(i)));
1107         }
1108         break;
1109       case Instruction::Select:
1110         Code = bitc::CST_CODE_CE_SELECT;
1111         Record.push_back(VE.getValueID(C->getOperand(0)));
1112         Record.push_back(VE.getValueID(C->getOperand(1)));
1113         Record.push_back(VE.getValueID(C->getOperand(2)));
1114         break;
1115       case Instruction::ExtractElement:
1116         Code = bitc::CST_CODE_CE_EXTRACTELT;
1117         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1118         Record.push_back(VE.getValueID(C->getOperand(0)));
1119         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1120         Record.push_back(VE.getValueID(C->getOperand(1)));
1121         break;
1122       case Instruction::InsertElement:
1123         Code = bitc::CST_CODE_CE_INSERTELT;
1124         Record.push_back(VE.getValueID(C->getOperand(0)));
1125         Record.push_back(VE.getValueID(C->getOperand(1)));
1126         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1127         Record.push_back(VE.getValueID(C->getOperand(2)));
1128         break;
1129       case Instruction::ShuffleVector:
1130         // If the return type and argument types are the same, this is a
1131         // standard shufflevector instruction.  If the types are different,
1132         // then the shuffle is widening or truncating the input vectors, and
1133         // the argument type must also be encoded.
1134         if (C->getType() == C->getOperand(0)->getType()) {
1135           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1136         } else {
1137           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1138           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1139         }
1140         Record.push_back(VE.getValueID(C->getOperand(0)));
1141         Record.push_back(VE.getValueID(C->getOperand(1)));
1142         Record.push_back(VE.getValueID(C->getOperand(2)));
1143         break;
1144       case Instruction::ICmp:
1145       case Instruction::FCmp:
1146         Code = bitc::CST_CODE_CE_CMP;
1147         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1148         Record.push_back(VE.getValueID(C->getOperand(0)));
1149         Record.push_back(VE.getValueID(C->getOperand(1)));
1150         Record.push_back(CE->getPredicate());
1151         break;
1152       }
1153     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1154       Code = bitc::CST_CODE_BLOCKADDRESS;
1155       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1156       Record.push_back(VE.getValueID(BA->getFunction()));
1157       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1158     } else {
1159 #ifndef NDEBUG
1160       C->dump();
1161 #endif
1162       llvm_unreachable("Unknown constant!");
1163     }
1164     Stream.EmitRecord(Code, Record, AbbrevToUse);
1165     Record.clear();
1166   }
1167
1168   Stream.ExitBlock();
1169 }
1170
1171 static void WriteModuleConstants(const ValueEnumerator &VE,
1172                                  BitstreamWriter &Stream) {
1173   const ValueEnumerator::ValueList &Vals = VE.getValues();
1174
1175   // Find the first constant to emit, which is the first non-globalvalue value.
1176   // We know globalvalues have been emitted by WriteModuleInfo.
1177   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1178     if (!isa<GlobalValue>(Vals[i].first)) {
1179       WriteConstants(i, Vals.size(), VE, Stream, true);
1180       return;
1181     }
1182   }
1183 }
1184
1185 /// PushValueAndType - The file has to encode both the value and type id for
1186 /// many values, because we need to know what type to create for forward
1187 /// references.  However, most operands are not forward references, so this type
1188 /// field is not needed.
1189 ///
1190 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1191 /// instruction ID, then it is a forward reference, and it also includes the
1192 /// type ID.  The value ID that is written is encoded relative to the InstID.
1193 static bool PushValueAndType(const Value *V, unsigned InstID,
1194                              SmallVectorImpl<unsigned> &Vals,
1195                              ValueEnumerator &VE) {
1196   unsigned ValID = VE.getValueID(V);
1197   // Make encoding relative to the InstID.
1198   Vals.push_back(InstID - ValID);
1199   if (ValID >= InstID) {
1200     Vals.push_back(VE.getTypeID(V->getType()));
1201     return true;
1202   }
1203   return false;
1204 }
1205
1206 /// pushValue - Like PushValueAndType, but where the type of the value is
1207 /// omitted (perhaps it was already encoded in an earlier operand).
1208 static void pushValue(const Value *V, unsigned InstID,
1209                       SmallVectorImpl<unsigned> &Vals,
1210                       ValueEnumerator &VE) {
1211   unsigned ValID = VE.getValueID(V);
1212   Vals.push_back(InstID - ValID);
1213 }
1214
1215 static void pushValueSigned(const Value *V, unsigned InstID,
1216                             SmallVectorImpl<uint64_t> &Vals,
1217                             ValueEnumerator &VE) {
1218   unsigned ValID = VE.getValueID(V);
1219   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1220   emitSignedInt64(Vals, diff);
1221 }
1222
1223 /// WriteInstruction - Emit an instruction to the specified stream.
1224 static void WriteInstruction(const Instruction &I, unsigned InstID,
1225                              ValueEnumerator &VE, BitstreamWriter &Stream,
1226                              SmallVectorImpl<unsigned> &Vals) {
1227   unsigned Code = 0;
1228   unsigned AbbrevToUse = 0;
1229   VE.setInstructionID(&I);
1230   switch (I.getOpcode()) {
1231   default:
1232     if (Instruction::isCast(I.getOpcode())) {
1233       Code = bitc::FUNC_CODE_INST_CAST;
1234       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1235         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1236       Vals.push_back(VE.getTypeID(I.getType()));
1237       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1238     } else {
1239       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1240       Code = bitc::FUNC_CODE_INST_BINOP;
1241       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1242         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1243       pushValue(I.getOperand(1), InstID, Vals, VE);
1244       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1245       uint64_t Flags = GetOptimizationFlags(&I);
1246       if (Flags != 0) {
1247         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1248           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1249         Vals.push_back(Flags);
1250       }
1251     }
1252     break;
1253
1254   case Instruction::GetElementPtr:
1255     Code = bitc::FUNC_CODE_INST_GEP;
1256     if (cast<GEPOperator>(&I)->isInBounds())
1257       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1258     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1259       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1260     break;
1261   case Instruction::ExtractValue: {
1262     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1263     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1264     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1265     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1266       Vals.push_back(*i);
1267     break;
1268   }
1269   case Instruction::InsertValue: {
1270     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1271     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1272     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1273     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1274     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1275       Vals.push_back(*i);
1276     break;
1277   }
1278   case Instruction::Select:
1279     Code = bitc::FUNC_CODE_INST_VSELECT;
1280     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1281     pushValue(I.getOperand(2), InstID, Vals, VE);
1282     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1283     break;
1284   case Instruction::ExtractElement:
1285     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1286     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1287     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1288     break;
1289   case Instruction::InsertElement:
1290     Code = bitc::FUNC_CODE_INST_INSERTELT;
1291     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1292     pushValue(I.getOperand(1), InstID, Vals, VE);
1293     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1294     break;
1295   case Instruction::ShuffleVector:
1296     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1297     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1298     pushValue(I.getOperand(1), InstID, Vals, VE);
1299     pushValue(I.getOperand(2), InstID, Vals, VE);
1300     break;
1301   case Instruction::ICmp:
1302   case Instruction::FCmp:
1303     // compare returning Int1Ty or vector of Int1Ty
1304     Code = bitc::FUNC_CODE_INST_CMP2;
1305     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1306     pushValue(I.getOperand(1), InstID, Vals, VE);
1307     Vals.push_back(cast<CmpInst>(I).getPredicate());
1308     break;
1309
1310   case Instruction::Ret:
1311     {
1312       Code = bitc::FUNC_CODE_INST_RET;
1313       unsigned NumOperands = I.getNumOperands();
1314       if (NumOperands == 0)
1315         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1316       else if (NumOperands == 1) {
1317         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1318           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1319       } else {
1320         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1321           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1322       }
1323     }
1324     break;
1325   case Instruction::Br:
1326     {
1327       Code = bitc::FUNC_CODE_INST_BR;
1328       const BranchInst &II = cast<BranchInst>(I);
1329       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1330       if (II.isConditional()) {
1331         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1332         pushValue(II.getCondition(), InstID, Vals, VE);
1333       }
1334     }
1335     break;
1336   case Instruction::Switch:
1337     {
1338       Code = bitc::FUNC_CODE_INST_SWITCH;
1339       const SwitchInst &SI = cast<SwitchInst>(I);
1340       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1341       pushValue(SI.getCondition(), InstID, Vals, VE);
1342       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1343       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1344            i != e; ++i) {
1345         Vals.push_back(VE.getValueID(i.getCaseValue()));
1346         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1347       }
1348     }
1349     break;
1350   case Instruction::IndirectBr:
1351     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1352     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1353     // Encode the address operand as relative, but not the basic blocks.
1354     pushValue(I.getOperand(0), InstID, Vals, VE);
1355     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1356       Vals.push_back(VE.getValueID(I.getOperand(i)));
1357     break;
1358
1359   case Instruction::Invoke: {
1360     const InvokeInst *II = cast<InvokeInst>(&I);
1361     const Value *Callee(II->getCalledValue());
1362     PointerType *PTy = cast<PointerType>(Callee->getType());
1363     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1364     Code = bitc::FUNC_CODE_INST_INVOKE;
1365
1366     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1367     Vals.push_back(II->getCallingConv());
1368     Vals.push_back(VE.getValueID(II->getNormalDest()));
1369     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1370     PushValueAndType(Callee, InstID, Vals, VE);
1371
1372     // Emit value #'s for the fixed parameters.
1373     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1374       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1375
1376     // Emit type/value pairs for varargs params.
1377     if (FTy->isVarArg()) {
1378       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1379            i != e; ++i)
1380         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1381     }
1382     break;
1383   }
1384   case Instruction::Resume:
1385     Code = bitc::FUNC_CODE_INST_RESUME;
1386     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1387     break;
1388   case Instruction::Unreachable:
1389     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1390     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1391     break;
1392
1393   case Instruction::PHI: {
1394     const PHINode &PN = cast<PHINode>(I);
1395     Code = bitc::FUNC_CODE_INST_PHI;
1396     // With the newer instruction encoding, forward references could give
1397     // negative valued IDs.  This is most common for PHIs, so we use
1398     // signed VBRs.
1399     SmallVector<uint64_t, 128> Vals64;
1400     Vals64.push_back(VE.getTypeID(PN.getType()));
1401     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1402       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1403       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1404     }
1405     // Emit a Vals64 vector and exit.
1406     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1407     Vals64.clear();
1408     return;
1409   }
1410
1411   case Instruction::LandingPad: {
1412     const LandingPadInst &LP = cast<LandingPadInst>(I);
1413     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1414     Vals.push_back(VE.getTypeID(LP.getType()));
1415     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1416     Vals.push_back(LP.isCleanup());
1417     Vals.push_back(LP.getNumClauses());
1418     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1419       if (LP.isCatch(I))
1420         Vals.push_back(LandingPadInst::Catch);
1421       else
1422         Vals.push_back(LandingPadInst::Filter);
1423       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1424     }
1425     break;
1426   }
1427
1428   case Instruction::Alloca: {
1429     Code = bitc::FUNC_CODE_INST_ALLOCA;
1430     Vals.push_back(VE.getTypeID(I.getType()));
1431     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1432     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1433     const AllocaInst &AI = cast<AllocaInst>(I);
1434     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1435     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1436            "not enough bits for maximum alignment");
1437     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1438     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1439     Vals.push_back(AlignRecord);
1440     break;
1441   }
1442
1443   case Instruction::Load:
1444     if (cast<LoadInst>(I).isAtomic()) {
1445       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1446       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1447     } else {
1448       Code = bitc::FUNC_CODE_INST_LOAD;
1449       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1450         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1451     }
1452     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1453     Vals.push_back(cast<LoadInst>(I).isVolatile());
1454     if (cast<LoadInst>(I).isAtomic()) {
1455       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1456       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1457     }
1458     break;
1459   case Instruction::Store:
1460     if (cast<StoreInst>(I).isAtomic())
1461       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1462     else
1463       Code = bitc::FUNC_CODE_INST_STORE;
1464     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1465     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1466     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1467     Vals.push_back(cast<StoreInst>(I).isVolatile());
1468     if (cast<StoreInst>(I).isAtomic()) {
1469       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1470       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1471     }
1472     break;
1473   case Instruction::AtomicCmpXchg:
1474     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1475     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1476     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1477     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1478     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1479     Vals.push_back(GetEncodedOrdering(
1480                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1481     Vals.push_back(GetEncodedSynchScope(
1482                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1483     Vals.push_back(GetEncodedOrdering(
1484                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1485     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1486     break;
1487   case Instruction::AtomicRMW:
1488     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1489     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1490     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1491     Vals.push_back(GetEncodedRMWOperation(
1492                      cast<AtomicRMWInst>(I).getOperation()));
1493     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1494     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1495     Vals.push_back(GetEncodedSynchScope(
1496                      cast<AtomicRMWInst>(I).getSynchScope()));
1497     break;
1498   case Instruction::Fence:
1499     Code = bitc::FUNC_CODE_INST_FENCE;
1500     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1501     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1502     break;
1503   case Instruction::Call: {
1504     const CallInst &CI = cast<CallInst>(I);
1505     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1506     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1507
1508     Code = bitc::FUNC_CODE_INST_CALL;
1509
1510     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1511     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1512                    unsigned(CI.isMustTailCall()) << 14);
1513     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1514
1515     // Emit value #'s for the fixed parameters.
1516     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1517       // Check for labels (can happen with asm labels).
1518       if (FTy->getParamType(i)->isLabelTy())
1519         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1520       else
1521         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1522     }
1523
1524     // Emit type/value pairs for varargs params.
1525     if (FTy->isVarArg()) {
1526       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1527            i != e; ++i)
1528         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1529     }
1530     break;
1531   }
1532   case Instruction::VAArg:
1533     Code = bitc::FUNC_CODE_INST_VAARG;
1534     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1535     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1536     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1537     break;
1538   }
1539
1540   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1541   Vals.clear();
1542 }
1543
1544 // Emit names for globals/functions etc.
1545 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1546                                   const ValueEnumerator &VE,
1547                                   BitstreamWriter &Stream) {
1548   if (VST.empty()) return;
1549   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1550
1551   // FIXME: Set up the abbrev, we know how many values there are!
1552   // FIXME: We know if the type names can use 7-bit ascii.
1553   SmallVector<unsigned, 64> NameVals;
1554
1555   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1556        SI != SE; ++SI) {
1557
1558     const ValueName &Name = *SI;
1559
1560     // Figure out the encoding to use for the name.
1561     bool is7Bit = true;
1562     bool isChar6 = true;
1563     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1564          C != E; ++C) {
1565       if (isChar6)
1566         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1567       if ((unsigned char)*C & 128) {
1568         is7Bit = false;
1569         break;  // don't bother scanning the rest.
1570       }
1571     }
1572
1573     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1574
1575     // VST_ENTRY:   [valueid, namechar x N]
1576     // VST_BBENTRY: [bbid, namechar x N]
1577     unsigned Code;
1578     if (isa<BasicBlock>(SI->getValue())) {
1579       Code = bitc::VST_CODE_BBENTRY;
1580       if (isChar6)
1581         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1582     } else {
1583       Code = bitc::VST_CODE_ENTRY;
1584       if (isChar6)
1585         AbbrevToUse = VST_ENTRY_6_ABBREV;
1586       else if (is7Bit)
1587         AbbrevToUse = VST_ENTRY_7_ABBREV;
1588     }
1589
1590     NameVals.push_back(VE.getValueID(SI->getValue()));
1591     for (const char *P = Name.getKeyData(),
1592          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1593       NameVals.push_back((unsigned char)*P);
1594
1595     // Emit the finished record.
1596     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1597     NameVals.clear();
1598   }
1599   Stream.ExitBlock();
1600 }
1601
1602 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1603                          BitstreamWriter &Stream) {
1604   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1605   unsigned Code;
1606   if (isa<BasicBlock>(Order.V))
1607     Code = bitc::USELIST_CODE_BB;
1608   else
1609     Code = bitc::USELIST_CODE_DEFAULT;
1610
1611   SmallVector<uint64_t, 64> Record;
1612   for (unsigned I : Order.Shuffle)
1613     Record.push_back(I);
1614   Record.push_back(VE.getValueID(Order.V));
1615   Stream.EmitRecord(Code, Record);
1616 }
1617
1618 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1619                               BitstreamWriter &Stream) {
1620   auto hasMore = [&]() {
1621     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1622   };
1623   if (!hasMore())
1624     // Nothing to do.
1625     return;
1626
1627   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1628   while (hasMore()) {
1629     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1630     VE.UseListOrders.pop_back();
1631   }
1632   Stream.ExitBlock();
1633 }
1634
1635 /// WriteFunction - Emit a function body to the module stream.
1636 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1637                           BitstreamWriter &Stream) {
1638   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1639   VE.incorporateFunction(F);
1640
1641   SmallVector<unsigned, 64> Vals;
1642
1643   // Emit the number of basic blocks, so the reader can create them ahead of
1644   // time.
1645   Vals.push_back(VE.getBasicBlocks().size());
1646   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1647   Vals.clear();
1648
1649   // If there are function-local constants, emit them now.
1650   unsigned CstStart, CstEnd;
1651   VE.getFunctionConstantRange(CstStart, CstEnd);
1652   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1653
1654   // If there is function-local metadata, emit it now.
1655   WriteFunctionLocalMetadata(F, VE, Stream);
1656
1657   // Keep a running idea of what the instruction ID is.
1658   unsigned InstID = CstEnd;
1659
1660   bool NeedsMetadataAttachment = false;
1661
1662   DebugLoc LastDL;
1663
1664   // Finally, emit all the instructions, in order.
1665   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1666     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1667          I != E; ++I) {
1668       WriteInstruction(*I, InstID, VE, Stream, Vals);
1669
1670       if (!I->getType()->isVoidTy())
1671         ++InstID;
1672
1673       // If the instruction has metadata, write a metadata attachment later.
1674       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1675
1676       // If the instruction has a debug location, emit it.
1677       DebugLoc DL = I->getDebugLoc();
1678       if (DL.isUnknown()) {
1679         // nothing todo.
1680       } else if (DL == LastDL) {
1681         // Just repeat the same debug loc as last time.
1682         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1683       } else {
1684         MDNode *Scope, *IA;
1685         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1686
1687         Vals.push_back(DL.getLine());
1688         Vals.push_back(DL.getCol());
1689         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1690         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1691         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1692         Vals.clear();
1693
1694         LastDL = DL;
1695       }
1696     }
1697
1698   // Emit names for all the instructions etc.
1699   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1700
1701   if (NeedsMetadataAttachment)
1702     WriteMetadataAttachment(F, VE, Stream);
1703   if (shouldPreserveBitcodeUseListOrder())
1704     WriteUseListBlock(&F, VE, Stream);
1705   VE.purgeFunction();
1706   Stream.ExitBlock();
1707 }
1708
1709 // Emit blockinfo, which defines the standard abbreviations etc.
1710 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1711   // We only want to emit block info records for blocks that have multiple
1712   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1713   // Other blocks can define their abbrevs inline.
1714   Stream.EnterBlockInfoBlock(2);
1715
1716   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1717     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1718     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1719     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1720     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1721     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1722     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1723                                    Abbv) != VST_ENTRY_8_ABBREV)
1724       llvm_unreachable("Unexpected abbrev ordering!");
1725   }
1726
1727   { // 7-bit fixed width VST_ENTRY strings.
1728     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1729     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1730     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1731     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1732     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1733     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1734                                    Abbv) != VST_ENTRY_7_ABBREV)
1735       llvm_unreachable("Unexpected abbrev ordering!");
1736   }
1737   { // 6-bit char6 VST_ENTRY strings.
1738     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1739     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1740     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1741     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1742     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1743     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1744                                    Abbv) != VST_ENTRY_6_ABBREV)
1745       llvm_unreachable("Unexpected abbrev ordering!");
1746   }
1747   { // 6-bit char6 VST_BBENTRY strings.
1748     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1749     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1750     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1751     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1752     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1753     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1754                                    Abbv) != VST_BBENTRY_6_ABBREV)
1755       llvm_unreachable("Unexpected abbrev ordering!");
1756   }
1757
1758
1759
1760   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1761     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1762     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1763     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1764                               Log2_32_Ceil(VE.getTypes().size()+1)));
1765     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1766                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1767       llvm_unreachable("Unexpected abbrev ordering!");
1768   }
1769
1770   { // INTEGER abbrev for CONSTANTS_BLOCK.
1771     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1772     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1773     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1774     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1775                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1776       llvm_unreachable("Unexpected abbrev ordering!");
1777   }
1778
1779   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1780     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1781     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1782     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1784                               Log2_32_Ceil(VE.getTypes().size()+1)));
1785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1786
1787     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1788                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1789       llvm_unreachable("Unexpected abbrev ordering!");
1790   }
1791   { // NULL abbrev for CONSTANTS_BLOCK.
1792     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1793     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1794     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1795                                    Abbv) != CONSTANTS_NULL_Abbrev)
1796       llvm_unreachable("Unexpected abbrev ordering!");
1797   }
1798
1799   // FIXME: This should only use space for first class types!
1800
1801   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1802     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1803     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1804     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1805     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1807     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1808                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1809       llvm_unreachable("Unexpected abbrev ordering!");
1810   }
1811   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1812     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1813     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1814     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1815     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1817     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1818                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1819       llvm_unreachable("Unexpected abbrev ordering!");
1820   }
1821   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1822     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1823     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1824     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1825     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1826     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1827     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1828     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1829                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1830       llvm_unreachable("Unexpected abbrev ordering!");
1831   }
1832   { // INST_CAST abbrev for FUNCTION_BLOCK.
1833     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1834     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1835     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1836     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1837                               Log2_32_Ceil(VE.getTypes().size()+1)));
1838     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1839     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1840                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1841       llvm_unreachable("Unexpected abbrev ordering!");
1842   }
1843
1844   { // INST_RET abbrev for FUNCTION_BLOCK.
1845     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1846     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1847     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1848                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1849       llvm_unreachable("Unexpected abbrev ordering!");
1850   }
1851   { // INST_RET abbrev for FUNCTION_BLOCK.
1852     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1853     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1854     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1855     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1856                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1857       llvm_unreachable("Unexpected abbrev ordering!");
1858   }
1859   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1860     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1861     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1862     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1863                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1864       llvm_unreachable("Unexpected abbrev ordering!");
1865   }
1866
1867   Stream.ExitBlock();
1868 }
1869
1870 /// WriteModule - Emit the specified module to the bitstream.
1871 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1872   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1873
1874   SmallVector<unsigned, 1> Vals;
1875   unsigned CurVersion = 1;
1876   Vals.push_back(CurVersion);
1877   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1878
1879   // Analyze the module, enumerating globals, functions, etc.
1880   ValueEnumerator VE(M);
1881
1882   // Emit blockinfo, which defines the standard abbreviations etc.
1883   WriteBlockInfo(VE, Stream);
1884
1885   // Emit information about attribute groups.
1886   WriteAttributeGroupTable(VE, Stream);
1887
1888   // Emit information about parameter attributes.
1889   WriteAttributeTable(VE, Stream);
1890
1891   // Emit information describing all of the types in the module.
1892   WriteTypeTable(VE, Stream);
1893
1894   writeComdats(VE, Stream);
1895
1896   // Emit top-level description of module, including target triple, inline asm,
1897   // descriptors for global variables, and function prototype info.
1898   WriteModuleInfo(M, VE, Stream);
1899
1900   // Emit constants.
1901   WriteModuleConstants(VE, Stream);
1902
1903   // Emit metadata.
1904   WriteModuleMetadata(M, VE, Stream);
1905
1906   // Emit metadata.
1907   WriteModuleMetadataStore(M, Stream);
1908
1909   // Emit names for globals/functions etc.
1910   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1911
1912   // Emit module-level use-lists.
1913   if (shouldPreserveBitcodeUseListOrder())
1914     WriteUseListBlock(nullptr, VE, Stream);
1915
1916   // Emit function bodies.
1917   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1918     if (!F->isDeclaration())
1919       WriteFunction(*F, VE, Stream);
1920
1921   Stream.ExitBlock();
1922 }
1923
1924 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1925 /// header and trailer to make it compatible with the system archiver.  To do
1926 /// this we emit the following header, and then emit a trailer that pads the
1927 /// file out to be a multiple of 16 bytes.
1928 ///
1929 /// struct bc_header {
1930 ///   uint32_t Magic;         // 0x0B17C0DE
1931 ///   uint32_t Version;       // Version, currently always 0.
1932 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1933 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1934 ///   uint32_t CPUType;       // CPU specifier.
1935 ///   ... potentially more later ...
1936 /// };
1937 enum {
1938   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1939   DarwinBCHeaderSize = 5*4
1940 };
1941
1942 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
1943                                uint32_t &Position) {
1944   Buffer[Position + 0] = (unsigned char) (Value >>  0);
1945   Buffer[Position + 1] = (unsigned char) (Value >>  8);
1946   Buffer[Position + 2] = (unsigned char) (Value >> 16);
1947   Buffer[Position + 3] = (unsigned char) (Value >> 24);
1948   Position += 4;
1949 }
1950
1951 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
1952                                          const Triple &TT) {
1953   unsigned CPUType = ~0U;
1954
1955   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1956   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1957   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1958   // specific constants here because they are implicitly part of the Darwin ABI.
1959   enum {
1960     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1961     DARWIN_CPU_TYPE_X86        = 7,
1962     DARWIN_CPU_TYPE_ARM        = 12,
1963     DARWIN_CPU_TYPE_POWERPC    = 18
1964   };
1965
1966   Triple::ArchType Arch = TT.getArch();
1967   if (Arch == Triple::x86_64)
1968     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1969   else if (Arch == Triple::x86)
1970     CPUType = DARWIN_CPU_TYPE_X86;
1971   else if (Arch == Triple::ppc)
1972     CPUType = DARWIN_CPU_TYPE_POWERPC;
1973   else if (Arch == Triple::ppc64)
1974     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1975   else if (Arch == Triple::arm || Arch == Triple::thumb)
1976     CPUType = DARWIN_CPU_TYPE_ARM;
1977
1978   // Traditional Bitcode starts after header.
1979   assert(Buffer.size() >= DarwinBCHeaderSize &&
1980          "Expected header size to be reserved");
1981   unsigned BCOffset = DarwinBCHeaderSize;
1982   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
1983
1984   // Write the magic and version.
1985   unsigned Position = 0;
1986   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
1987   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
1988   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
1989   WriteInt32ToBuffer(BCSize     , Buffer, Position);
1990   WriteInt32ToBuffer(CPUType    , Buffer, Position);
1991
1992   // If the file is not a multiple of 16 bytes, insert dummy padding.
1993   while (Buffer.size() & 15)
1994     Buffer.push_back(0);
1995 }
1996
1997 /// WriteBitcodeToFile - Write the specified module to the specified output
1998 /// stream.
1999 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2000   SmallVector<char, 0> Buffer;
2001   Buffer.reserve(256*1024);
2002
2003   // If this is darwin or another generic macho target, reserve space for the
2004   // header.
2005   Triple TT(M->getTargetTriple());
2006   if (TT.isOSDarwin())
2007     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2008
2009   // Emit the module into the buffer.
2010   {
2011     BitstreamWriter Stream(Buffer);
2012
2013     // Emit the file header.
2014     Stream.Emit((unsigned)'B', 8);
2015     Stream.Emit((unsigned)'C', 8);
2016     Stream.Emit(0x0, 4);
2017     Stream.Emit(0xC, 4);
2018     Stream.Emit(0xE, 4);
2019     Stream.Emit(0xD, 4);
2020
2021     // Emit the module.
2022     WriteModule(M, Stream);
2023   }
2024
2025   if (TT.isOSDarwin())
2026     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2027
2028   // Write the generated bitstream to "Out".
2029   Out.write((char*)&Buffer.front(), Buffer.size());
2030 }