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     Vals.push_back(VE.getTypeID(GV.getType()));
 659     Vals.push_back(GV.isConstant());
 660     Vals.push_back(GV.isDeclaration() ? 0 :
 661                    (VE.getValueID(GV.getInitializer()) + 1));
 662     Vals.push_back(getEncodedLinkage(GV));
 663     Vals.push_back(Log2_32(GV.getAlignment())+1);
 664     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 665     if (GV.isThreadLocal() ||
 666         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 667         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 668         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 669         GV.hasComdat()) {
 670       Vals.push_back(getEncodedVisibility(GV));
 671       Vals.push_back(getEncodedThreadLocalMode(GV));
 672       Vals.push_back(GV.hasUnnamedAddr());
 673       Vals.push_back(GV.isExternallyInitialized());
 674       Vals.push_back(getEncodedDLLStorageClass(GV));
 675       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 676     } else {
 677       AbbrevToUse = SimpleGVarAbbrev;
 678     }
 679
 680     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 681     Vals.clear();
 682   }
 683
 684   // Emit the function proto information.
 685   for (const Function &F : *M) {
 686     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 687     //             section, visibility, gc, unnamed_addr, prologuedata,
 688     //             dllstorageclass, comdat, prefixdata]
 689     Vals.push_back(VE.getTypeID(F.getType()));
 690     Vals.push_back(F.getCallingConv());
 691     Vals.push_back(F.isDeclaration());
 692     Vals.push_back(getEncodedLinkage(F));
 693     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 694     Vals.push_back(Log2_32(F.getAlignment())+1);
 695     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 696     Vals.push_back(getEncodedVisibility(F));
 697     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 698     Vals.push_back(F.hasUnnamedAddr());
 699     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 700                                        : 0);
 701     Vals.push_back(getEncodedDLLStorageClass(F));
 702     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 703     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 704                                      : 0);
 705
 706     unsigned AbbrevToUse = 0;
 707     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 708     Vals.clear();
 709   }
 710
 711   // Emit the alias information.
 712   for (const GlobalAlias &A : M->aliases()) {
 713     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 714     Vals.push_back(VE.getTypeID(A.getType()));
 715     Vals.push_back(VE.getValueID(A.getAliasee()));
 716     Vals.push_back(getEncodedLinkage(A));
 717     Vals.push_back(getEncodedVisibility(A));
 718     Vals.push_back(getEncodedDLLStorageClass(A));
 719     Vals.push_back(getEncodedThreadLocalMode(A));
 720     Vals.push_back(A.hasUnnamedAddr());
 721     unsigned AbbrevToUse = 0;
 722     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 723     Vals.clear();
 724   }
 725 }
 726
 727 static uint64_t GetOptimizationFlags(const Value *V) {
 728   uint64_t Flags = 0;
 729
 730   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 731     if (OBO->hasNoSignedWrap())
 732       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 733     if (OBO->hasNoUnsignedWrap())
 734       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 735   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 736     if (PEO->isExact())
 737       Flags |= 1 << bitc::PEO_EXACT;
 738   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 739     if (FPMO->hasUnsafeAlgebra())
 740       Flags |= FastMathFlags::UnsafeAlgebra;
 741     if (FPMO->hasNoNaNs())
 742       Flags |= FastMathFlags::NoNaNs;
 743     if (FPMO->hasNoInfs())
 744       Flags |= FastMathFlags::NoInfs;
 745     if (FPMO->hasNoSignedZeros())
 746       Flags |= FastMathFlags::NoSignedZeros;
 747     if (FPMO->hasAllowReciprocal())
 748       Flags |= FastMathFlags::AllowReciprocal;
 749   }
 750
 751   return Flags;
 752 }
 753
 754 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 755                                  const ValueEnumerator &VE,
 756                                  BitstreamWriter &Stream,
 757                                  SmallVectorImpl<uint64_t> &Record) {
 758   // Mimic an MDNode with a value as one operand.
 759   Value *V = MD->getValue();
 760   Record.push_back(VE.getTypeID(V->getType()));
 761   Record.push_back(VE.getValueID(V));
 762   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 763   Record.clear();
 764 }
 765
 766 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 767                          BitstreamWriter &Stream,
 768                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 769   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 770     Metadata *MD = N->getOperand(i);
 771     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 772            "Unexpected function-local metadata");
 773     Record.push_back(VE.getMetadataOrNullID(MD));
 774   }
 775   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 776                                     : bitc::METADATA_NODE,
 777                     Record, Abbrev);
 778   Record.clear();
 779 }
 780
 781 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 782                             BitstreamWriter &Stream,
 783                             SmallVectorImpl<uint64_t> &Record,
 784                             unsigned Abbrev) {
 785   Record.push_back(N->isDistinct());
 786   Record.push_back(N->getLine());
 787   Record.push_back(N->getColumn());
 788   Record.push_back(VE.getMetadataID(N->getScope()));
 789   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 790
 791   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 792   Record.clear();
 793 }
 794
 795 static void WriteGenericDebugNode(const GenericDebugNode *,
 796                                   const ValueEnumerator &, BitstreamWriter &,
 797                                   SmallVectorImpl<uint64_t> &, unsigned) {
 798   llvm_unreachable("unimplemented");
 799 }
 800
 801 static void WriteModuleMetadata(const Module *M,
 802                                 const ValueEnumerator &VE,
 803                                 BitstreamWriter &Stream) {
 804   const auto &MDs = VE.getMDs();
 805   if (MDs.empty() && M->named_metadata_empty())
 806     return;
 807
 808   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 809
 810   unsigned MDSAbbrev = 0;
 811   if (VE.hasMDString()) {
 812     // Abbrev for METADATA_STRING.
 813     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 814     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 815     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 817     MDSAbbrev = Stream.EmitAbbrev(Abbv);
 818   }
 819
 820   unsigned MDLocationAbbrev = 0;
 821   if (VE.hasMDLocation()) {
 822     // Abbrev for METADATA_LOCATION.
 823     //
 824     // Assume the column is usually under 128, and always output the inlined-at
 825     // location (it's never more expensive than building an array size 1).
 826     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 827     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
 828     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 829     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 830     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 831     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 832     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 833     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
 834   }
 835
 836   unsigned NameAbbrev = 0;
 837   if (!M->named_metadata_empty()) {
 838     // Abbrev for METADATA_NAME.
 839     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 840     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
 841     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 842     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 843     NameAbbrev = Stream.EmitAbbrev(Abbv);
 844   }
 845
 846   unsigned MDTupleAbbrev = 0;
 847   unsigned GenericDebugNodeAbbrev = 0;
 848   SmallVector<uint64_t, 64> Record;
 849   for (const Metadata *MD : MDs) {
 850     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
 851       switch (N->getMetadataID()) {
 852       default:
 853         llvm_unreachable("Invalid MDNode subclass");
 854 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
 855   case Metadata::CLASS##Kind:                                                  \
 856     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
 857     continue;
 858 #include "llvm/IR/Metadata.def"
 859       }
 860     }
 861     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
 862       WriteValueAsMetadata(MDC, VE, Stream, Record);
 863       continue;
 864     }
 865     const MDString *MDS = cast<MDString>(MD);
 866     // Code: [strchar x N]
 867     Record.append(MDS->bytes_begin(), MDS->bytes_end());
 868
 869     // Emit the finished record.
 870     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 871     Record.clear();
 872   }
 873
 874   // Write named metadata.
 875   for (const NamedMDNode &NMD : M->named_metadata()) {
 876     // Write name.
 877     StringRef Str = NMD.getName();
 878     Record.append(Str.bytes_begin(), Str.bytes_end());
 879     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
 880     Record.clear();
 881
 882     // Write named metadata operands.
 883     for (const MDNode *N : NMD.operands())
 884       Record.push_back(VE.getMetadataID(N));
 885     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 886     Record.clear();
 887   }
 888
 889   Stream.ExitBlock();
 890 }
 891
 892 static void WriteFunctionLocalMetadata(const Function &F,
 893                                        const ValueEnumerator &VE,
 894                                        BitstreamWriter &Stream) {
 895   bool StartedMetadataBlock = false;
 896   SmallVector<uint64_t, 64> Record;
 897   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
 898       VE.getFunctionLocalMDs();
 899   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 900     assert(MDs[i] && "Expected valid function-local metadata");
 901     if (!StartedMetadataBlock) {
 902       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 903       StartedMetadataBlock = true;
 904     }
 905     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
 906   }
 907
 908   if (StartedMetadataBlock)
 909     Stream.ExitBlock();
 910 }
 911
 912 static void WriteMetadataAttachment(const Function &F,
 913                                     const ValueEnumerator &VE,
 914                                     BitstreamWriter &Stream) {
 915   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 916
 917   SmallVector<uint64_t, 64> Record;
 918
 919   // Write metadata attachments
 920   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 921   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
 922
 923   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 924     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 925          I != E; ++I) {
 926       MDs.clear();
 927       I->getAllMetadataOtherThanDebugLoc(MDs);
 928
 929       // If no metadata, ignore instruction.
 930       if (MDs.empty()) continue;
 931
 932       Record.push_back(VE.getInstructionID(I));
 933
 934       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 935         Record.push_back(MDs[i].first);
 936         Record.push_back(VE.getMetadataID(MDs[i].second));
 937       }
 938       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 939       Record.clear();
 940     }
 941
 942   Stream.ExitBlock();
 943 }
 944
 945 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 946   SmallVector<uint64_t, 64> Record;
 947
 948   // Write metadata kinds
 949   // METADATA_KIND - [n x [id, name]]
 950   SmallVector<StringRef, 8> Names;
 951   M->getMDKindNames(Names);
 952
 953   if (Names.empty()) return;
 954
 955   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 956
 957   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 958     Record.push_back(MDKindID);
 959     StringRef KName = Names[MDKindID];
 960     Record.append(KName.begin(), KName.end());
 961
 962     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 963     Record.clear();
 964   }
 965
 966   Stream.ExitBlock();
 967 }
 968
 969 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 970   if ((int64_t)V >= 0)
 971     Vals.push_back(V << 1);
 972   else
 973     Vals.push_back((-V << 1) | 1);
 974 }
 975
 976 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 977                            const ValueEnumerator &VE,
 978                            BitstreamWriter &Stream, bool isGlobal) {
 979   if (FirstVal == LastVal) return;
 980
 981   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 982
 983   unsigned AggregateAbbrev = 0;
 984   unsigned String8Abbrev = 0;
 985   unsigned CString7Abbrev = 0;
 986   unsigned CString6Abbrev = 0;
 987   // If this is a constant pool for the module, emit module-specific abbrevs.
 988   if (isGlobal) {
 989     // Abbrev for CST_CODE_AGGREGATE.
 990     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 991     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 992     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 993     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 994     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 995
 996     // Abbrev for CST_CODE_STRING.
 997     Abbv = new BitCodeAbbrev();
 998     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 999     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1000     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1001     String8Abbrev = Stream.EmitAbbrev(Abbv);
1002     // Abbrev for CST_CODE_CSTRING.
1003     Abbv = new BitCodeAbbrev();
1004     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1005     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1006     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1007     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1008     // Abbrev for CST_CODE_CSTRING.
1009     Abbv = new BitCodeAbbrev();
1010     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1011     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1012     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1013     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1014   }
1015
1016   SmallVector<uint64_t, 64> Record;
1017
1018   const ValueEnumerator::ValueList &Vals = VE.getValues();
1019   Type *LastTy = nullptr;
1020   for (unsigned i = FirstVal; i != LastVal; ++i) {
1021     const Value *V = Vals[i].first;
1022     // If we need to switch types, do so now.
1023     if (V->getType() != LastTy) {
1024       LastTy = V->getType();
1025       Record.push_back(VE.getTypeID(LastTy));
1026       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1027                         CONSTANTS_SETTYPE_ABBREV);
1028       Record.clear();
1029     }
1030
1031     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1032       Record.push_back(unsigned(IA->hasSideEffects()) |
1033                        unsigned(IA->isAlignStack()) << 1 |
1034                        unsigned(IA->getDialect()&1) << 2);
1035
1036       // Add the asm string.
1037       const std::string &AsmStr = IA->getAsmString();
1038       Record.push_back(AsmStr.size());
1039       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1040         Record.push_back(AsmStr[i]);
1041
1042       // Add the constraint string.
1043       const std::string &ConstraintStr = IA->getConstraintString();
1044       Record.push_back(ConstraintStr.size());
1045       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1046         Record.push_back(ConstraintStr[i]);
1047       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1048       Record.clear();
1049       continue;
1050     }
1051     const Constant *C = cast<Constant>(V);
1052     unsigned Code = -1U;
1053     unsigned AbbrevToUse = 0;
1054     if (C->isNullValue()) {
1055       Code = bitc::CST_CODE_NULL;
1056     } else if (isa<UndefValue>(C)) {
1057       Code = bitc::CST_CODE_UNDEF;
1058     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1059       if (IV->getBitWidth() <= 64) {
1060         uint64_t V = IV->getSExtValue();
1061         emitSignedInt64(Record, V);
1062         Code = bitc::CST_CODE_INTEGER;
1063         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1064       } else {                             // Wide integers, > 64 bits in size.
1065         // We have an arbitrary precision integer value to write whose
1066         // bit width is > 64. However, in canonical unsigned integer
1067         // format it is likely that the high bits are going to be zero.
1068         // So, we only write the number of active words.
1069         unsigned NWords = IV->getValue().getActiveWords();
1070         const uint64_t *RawWords = IV->getValue().getRawData();
1071         for (unsigned i = 0; i != NWords; ++i) {
1072           emitSignedInt64(Record, RawWords[i]);
1073         }
1074         Code = bitc::CST_CODE_WIDE_INTEGER;
1075       }
1076     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1077       Code = bitc::CST_CODE_FLOAT;
1078       Type *Ty = CFP->getType();
1079       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1080         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1081       } else if (Ty->isX86_FP80Ty()) {
1082         // api needed to prevent premature destruction
1083         // bits are not in the same order as a normal i80 APInt, compensate.
1084         APInt api = CFP->getValueAPF().bitcastToAPInt();
1085         const uint64_t *p = api.getRawData();
1086         Record.push_back((p[1] << 48) | (p[0] >> 16));
1087         Record.push_back(p[0] & 0xffffLL);
1088       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1089         APInt api = CFP->getValueAPF().bitcastToAPInt();
1090         const uint64_t *p = api.getRawData();
1091         Record.push_back(p[0]);
1092         Record.push_back(p[1]);
1093       } else {
1094         assert (0 && "Unknown FP type!");
1095       }
1096     } else if (isa<ConstantDataSequential>(C) &&
1097                cast<ConstantDataSequential>(C)->isString()) {
1098       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1099       // Emit constant strings specially.
1100       unsigned NumElts = Str->getNumElements();
1101       // If this is a null-terminated string, use the denser CSTRING encoding.
1102       if (Str->isCString()) {
1103         Code = bitc::CST_CODE_CSTRING;
1104         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1105       } else {
1106         Code = bitc::CST_CODE_STRING;
1107         AbbrevToUse = String8Abbrev;
1108       }
1109       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1110       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1111       for (unsigned i = 0; i != NumElts; ++i) {
1112         unsigned char V = Str->getElementAsInteger(i);
1113         Record.push_back(V);
1114         isCStr7 &= (V & 128) == 0;
1115         if (isCStrChar6)
1116           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1117       }
1118
1119       if (isCStrChar6)
1120         AbbrevToUse = CString6Abbrev;
1121       else if (isCStr7)
1122         AbbrevToUse = CString7Abbrev;
1123     } else if (const ConstantDataSequential *CDS =
1124                   dyn_cast<ConstantDataSequential>(C)) {
1125       Code = bitc::CST_CODE_DATA;
1126       Type *EltTy = CDS->getType()->getElementType();
1127       if (isa<IntegerType>(EltTy)) {
1128         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1129           Record.push_back(CDS->getElementAsInteger(i));
1130       } else if (EltTy->isFloatTy()) {
1131         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1132           union { float F; uint32_t I; };
1133           F = CDS->getElementAsFloat(i);
1134           Record.push_back(I);
1135         }
1136       } else {
1137         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1138         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1139           union { double F; uint64_t I; };
1140           F = CDS->getElementAsDouble(i);
1141           Record.push_back(I);
1142         }
1143       }
1144     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1145                isa<ConstantVector>(C)) {
1146       Code = bitc::CST_CODE_AGGREGATE;
1147       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1148         Record.push_back(VE.getValueID(C->getOperand(i)));
1149       AbbrevToUse = AggregateAbbrev;
1150     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1151       switch (CE->getOpcode()) {
1152       default:
1153         if (Instruction::isCast(CE->getOpcode())) {
1154           Code = bitc::CST_CODE_CE_CAST;
1155           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1156           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1157           Record.push_back(VE.getValueID(C->getOperand(0)));
1158           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1159         } else {
1160           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1161           Code = bitc::CST_CODE_CE_BINOP;
1162           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1163           Record.push_back(VE.getValueID(C->getOperand(0)));
1164           Record.push_back(VE.getValueID(C->getOperand(1)));
1165           uint64_t Flags = GetOptimizationFlags(CE);
1166           if (Flags != 0)
1167             Record.push_back(Flags);
1168         }
1169         break;
1170       case Instruction::GetElementPtr:
1171         Code = bitc::CST_CODE_CE_GEP;
1172         if (cast<GEPOperator>(C)->isInBounds())
1173           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1174         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1175           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1176           Record.push_back(VE.getValueID(C->getOperand(i)));
1177         }
1178         break;
1179       case Instruction::Select:
1180         Code = bitc::CST_CODE_CE_SELECT;
1181         Record.push_back(VE.getValueID(C->getOperand(0)));
1182         Record.push_back(VE.getValueID(C->getOperand(1)));
1183         Record.push_back(VE.getValueID(C->getOperand(2)));
1184         break;
1185       case Instruction::ExtractElement:
1186         Code = bitc::CST_CODE_CE_EXTRACTELT;
1187         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1188         Record.push_back(VE.getValueID(C->getOperand(0)));
1189         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1190         Record.push_back(VE.getValueID(C->getOperand(1)));
1191         break;
1192       case Instruction::InsertElement:
1193         Code = bitc::CST_CODE_CE_INSERTELT;
1194         Record.push_back(VE.getValueID(C->getOperand(0)));
1195         Record.push_back(VE.getValueID(C->getOperand(1)));
1196         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1197         Record.push_back(VE.getValueID(C->getOperand(2)));
1198         break;
1199       case Instruction::ShuffleVector:
1200         // If the return type and argument types are the same, this is a
1201         // standard shufflevector instruction.  If the types are different,
1202         // then the shuffle is widening or truncating the input vectors, and
1203         // the argument type must also be encoded.
1204         if (C->getType() == C->getOperand(0)->getType()) {
1205           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1206         } else {
1207           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1208           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1209         }
1210         Record.push_back(VE.getValueID(C->getOperand(0)));
1211         Record.push_back(VE.getValueID(C->getOperand(1)));
1212         Record.push_back(VE.getValueID(C->getOperand(2)));
1213         break;
1214       case Instruction::ICmp:
1215       case Instruction::FCmp:
1216         Code = bitc::CST_CODE_CE_CMP;
1217         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1218         Record.push_back(VE.getValueID(C->getOperand(0)));
1219         Record.push_back(VE.getValueID(C->getOperand(1)));
1220         Record.push_back(CE->getPredicate());
1221         break;
1222       }
1223     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1224       Code = bitc::CST_CODE_BLOCKADDRESS;
1225       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1226       Record.push_back(VE.getValueID(BA->getFunction()));
1227       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1228     } else {
1229 #ifndef NDEBUG
1230       C->dump();
1231 #endif
1232       llvm_unreachable("Unknown constant!");
1233     }
1234     Stream.EmitRecord(Code, Record, AbbrevToUse);
1235     Record.clear();
1236   }
1237
1238   Stream.ExitBlock();
1239 }
1240
1241 static void WriteModuleConstants(const ValueEnumerator &VE,
1242                                  BitstreamWriter &Stream) {
1243   const ValueEnumerator::ValueList &Vals = VE.getValues();
1244
1245   // Find the first constant to emit, which is the first non-globalvalue value.
1246   // We know globalvalues have been emitted by WriteModuleInfo.
1247   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1248     if (!isa<GlobalValue>(Vals[i].first)) {
1249       WriteConstants(i, Vals.size(), VE, Stream, true);
1250       return;
1251     }
1252   }
1253 }
1254
1255 /// PushValueAndType - The file has to encode both the value and type id for
1256 /// many values, because we need to know what type to create for forward
1257 /// references.  However, most operands are not forward references, so this type
1258 /// field is not needed.
1259 ///
1260 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1261 /// instruction ID, then it is a forward reference, and it also includes the
1262 /// type ID.  The value ID that is written is encoded relative to the InstID.
1263 static bool PushValueAndType(const Value *V, unsigned InstID,
1264                              SmallVectorImpl<unsigned> &Vals,
1265                              ValueEnumerator &VE) {
1266   unsigned ValID = VE.getValueID(V);
1267   // Make encoding relative to the InstID.
1268   Vals.push_back(InstID - ValID);
1269   if (ValID >= InstID) {
1270     Vals.push_back(VE.getTypeID(V->getType()));
1271     return true;
1272   }
1273   return false;
1274 }
1275
1276 /// pushValue - Like PushValueAndType, but where the type of the value is
1277 /// omitted (perhaps it was already encoded in an earlier operand).
1278 static void pushValue(const Value *V, unsigned InstID,
1279                       SmallVectorImpl<unsigned> &Vals,
1280                       ValueEnumerator &VE) {
1281   unsigned ValID = VE.getValueID(V);
1282   Vals.push_back(InstID - ValID);
1283 }
1284
1285 static void pushValueSigned(const Value *V, unsigned InstID,
1286                             SmallVectorImpl<uint64_t> &Vals,
1287                             ValueEnumerator &VE) {
1288   unsigned ValID = VE.getValueID(V);
1289   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1290   emitSignedInt64(Vals, diff);
1291 }
1292
1293 /// WriteInstruction - Emit an instruction to the specified stream.
1294 static void WriteInstruction(const Instruction &I, unsigned InstID,
1295                              ValueEnumerator &VE, BitstreamWriter &Stream,
1296                              SmallVectorImpl<unsigned> &Vals) {
1297   unsigned Code = 0;
1298   unsigned AbbrevToUse = 0;
1299   VE.setInstructionID(&I);
1300   switch (I.getOpcode()) {
1301   default:
1302     if (Instruction::isCast(I.getOpcode())) {
1303       Code = bitc::FUNC_CODE_INST_CAST;
1304       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1305         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1306       Vals.push_back(VE.getTypeID(I.getType()));
1307       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1308     } else {
1309       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1310       Code = bitc::FUNC_CODE_INST_BINOP;
1311       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1312         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1313       pushValue(I.getOperand(1), InstID, Vals, VE);
1314       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1315       uint64_t Flags = GetOptimizationFlags(&I);
1316       if (Flags != 0) {
1317         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1318           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1319         Vals.push_back(Flags);
1320       }
1321     }
1322     break;
1323
1324   case Instruction::GetElementPtr:
1325     Code = bitc::FUNC_CODE_INST_GEP;
1326     if (cast<GEPOperator>(&I)->isInBounds())
1327       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1328     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1329       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1330     break;
1331   case Instruction::ExtractValue: {
1332     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1333     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1334     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1335     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1336       Vals.push_back(*i);
1337     break;
1338   }
1339   case Instruction::InsertValue: {
1340     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1341     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1342     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1343     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1344     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1345       Vals.push_back(*i);
1346     break;
1347   }
1348   case Instruction::Select:
1349     Code = bitc::FUNC_CODE_INST_VSELECT;
1350     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1351     pushValue(I.getOperand(2), InstID, Vals, VE);
1352     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1353     break;
1354   case Instruction::ExtractElement:
1355     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1356     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1357     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1358     break;
1359   case Instruction::InsertElement:
1360     Code = bitc::FUNC_CODE_INST_INSERTELT;
1361     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1362     pushValue(I.getOperand(1), InstID, Vals, VE);
1363     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1364     break;
1365   case Instruction::ShuffleVector:
1366     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1367     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1368     pushValue(I.getOperand(1), InstID, Vals, VE);
1369     pushValue(I.getOperand(2), InstID, Vals, VE);
1370     break;
1371   case Instruction::ICmp:
1372   case Instruction::FCmp:
1373     // compare returning Int1Ty or vector of Int1Ty
1374     Code = bitc::FUNC_CODE_INST_CMP2;
1375     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1376     pushValue(I.getOperand(1), InstID, Vals, VE);
1377     Vals.push_back(cast<CmpInst>(I).getPredicate());
1378     break;
1379
1380   case Instruction::Ret:
1381     {
1382       Code = bitc::FUNC_CODE_INST_RET;
1383       unsigned NumOperands = I.getNumOperands();
1384       if (NumOperands == 0)
1385         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1386       else if (NumOperands == 1) {
1387         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1388           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1389       } else {
1390         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1391           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1392       }
1393     }
1394     break;
1395   case Instruction::Br:
1396     {
1397       Code = bitc::FUNC_CODE_INST_BR;
1398       const BranchInst &II = cast<BranchInst>(I);
1399       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1400       if (II.isConditional()) {
1401         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1402         pushValue(II.getCondition(), InstID, Vals, VE);
1403       }
1404     }
1405     break;
1406   case Instruction::Switch:
1407     {
1408       Code = bitc::FUNC_CODE_INST_SWITCH;
1409       const SwitchInst &SI = cast<SwitchInst>(I);
1410       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1411       pushValue(SI.getCondition(), InstID, Vals, VE);
1412       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1413       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1414            i != e; ++i) {
1415         Vals.push_back(VE.getValueID(i.getCaseValue()));
1416         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1417       }
1418     }
1419     break;
1420   case Instruction::IndirectBr:
1421     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1422     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1423     // Encode the address operand as relative, but not the basic blocks.
1424     pushValue(I.getOperand(0), InstID, Vals, VE);
1425     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1426       Vals.push_back(VE.getValueID(I.getOperand(i)));
1427     break;
1428
1429   case Instruction::Invoke: {
1430     const InvokeInst *II = cast<InvokeInst>(&I);
1431     const Value *Callee(II->getCalledValue());
1432     PointerType *PTy = cast<PointerType>(Callee->getType());
1433     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1434     Code = bitc::FUNC_CODE_INST_INVOKE;
1435
1436     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1437     Vals.push_back(II->getCallingConv());
1438     Vals.push_back(VE.getValueID(II->getNormalDest()));
1439     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1440     PushValueAndType(Callee, InstID, Vals, VE);
1441
1442     // Emit value #'s for the fixed parameters.
1443     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1444       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1445
1446     // Emit type/value pairs for varargs params.
1447     if (FTy->isVarArg()) {
1448       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1449            i != e; ++i)
1450         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1451     }
1452     break;
1453   }
1454   case Instruction::Resume:
1455     Code = bitc::FUNC_CODE_INST_RESUME;
1456     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1457     break;
1458   case Instruction::Unreachable:
1459     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1460     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1461     break;
1462
1463   case Instruction::PHI: {
1464     const PHINode &PN = cast<PHINode>(I);
1465     Code = bitc::FUNC_CODE_INST_PHI;
1466     // With the newer instruction encoding, forward references could give
1467     // negative valued IDs.  This is most common for PHIs, so we use
1468     // signed VBRs.
1469     SmallVector<uint64_t, 128> Vals64;
1470     Vals64.push_back(VE.getTypeID(PN.getType()));
1471     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1472       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1473       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1474     }
1475     // Emit a Vals64 vector and exit.
1476     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1477     Vals64.clear();
1478     return;
1479   }
1480
1481   case Instruction::LandingPad: {
1482     const LandingPadInst &LP = cast<LandingPadInst>(I);
1483     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1484     Vals.push_back(VE.getTypeID(LP.getType()));
1485     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1486     Vals.push_back(LP.isCleanup());
1487     Vals.push_back(LP.getNumClauses());
1488     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1489       if (LP.isCatch(I))
1490         Vals.push_back(LandingPadInst::Catch);
1491       else
1492         Vals.push_back(LandingPadInst::Filter);
1493       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1494     }
1495     break;
1496   }
1497
1498   case Instruction::Alloca: {
1499     Code = bitc::FUNC_CODE_INST_ALLOCA;
1500     Vals.push_back(VE.getTypeID(I.getType()));
1501     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1502     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1503     const AllocaInst &AI = cast<AllocaInst>(I);
1504     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1505     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1506            "not enough bits for maximum alignment");
1507     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1508     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1509     Vals.push_back(AlignRecord);
1510     break;
1511   }
1512
1513   case Instruction::Load:
1514     if (cast<LoadInst>(I).isAtomic()) {
1515       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1516       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1517     } else {
1518       Code = bitc::FUNC_CODE_INST_LOAD;
1519       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1520         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1521     }
1522     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1523     Vals.push_back(cast<LoadInst>(I).isVolatile());
1524     if (cast<LoadInst>(I).isAtomic()) {
1525       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1526       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1527     }
1528     break;
1529   case Instruction::Store:
1530     if (cast<StoreInst>(I).isAtomic())
1531       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1532     else
1533       Code = bitc::FUNC_CODE_INST_STORE;
1534     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1535     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1536     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1537     Vals.push_back(cast<StoreInst>(I).isVolatile());
1538     if (cast<StoreInst>(I).isAtomic()) {
1539       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1540       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1541     }
1542     break;
1543   case Instruction::AtomicCmpXchg:
1544     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1545     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1546     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1547     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1548     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1549     Vals.push_back(GetEncodedOrdering(
1550                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1551     Vals.push_back(GetEncodedSynchScope(
1552                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1553     Vals.push_back(GetEncodedOrdering(
1554                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1555     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1556     break;
1557   case Instruction::AtomicRMW:
1558     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1559     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1560     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1561     Vals.push_back(GetEncodedRMWOperation(
1562                      cast<AtomicRMWInst>(I).getOperation()));
1563     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1564     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1565     Vals.push_back(GetEncodedSynchScope(
1566                      cast<AtomicRMWInst>(I).getSynchScope()));
1567     break;
1568   case Instruction::Fence:
1569     Code = bitc::FUNC_CODE_INST_FENCE;
1570     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1571     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1572     break;
1573   case Instruction::Call: {
1574     const CallInst &CI = cast<CallInst>(I);
1575     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1576     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1577
1578     Code = bitc::FUNC_CODE_INST_CALL;
1579
1580     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1581     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1582                    unsigned(CI.isMustTailCall()) << 14);
1583     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1584
1585     // Emit value #'s for the fixed parameters.
1586     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1587       // Check for labels (can happen with asm labels).
1588       if (FTy->getParamType(i)->isLabelTy())
1589         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1590       else
1591         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1592     }
1593
1594     // Emit type/value pairs for varargs params.
1595     if (FTy->isVarArg()) {
1596       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1597            i != e; ++i)
1598         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1599     }
1600     break;
1601   }
1602   case Instruction::VAArg:
1603     Code = bitc::FUNC_CODE_INST_VAARG;
1604     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1605     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1606     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1607     break;
1608   }
1609
1610   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1611   Vals.clear();
1612 }
1613
1614 // Emit names for globals/functions etc.
1615 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1616                                   const ValueEnumerator &VE,
1617                                   BitstreamWriter &Stream) {
1618   if (VST.empty()) return;
1619   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1620
1621   // FIXME: Set up the abbrev, we know how many values there are!
1622   // FIXME: We know if the type names can use 7-bit ascii.
1623   SmallVector<unsigned, 64> NameVals;
1624
1625   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1626        SI != SE; ++SI) {
1627
1628     const ValueName &Name = *SI;
1629
1630     // Figure out the encoding to use for the name.
1631     bool is7Bit = true;
1632     bool isChar6 = true;
1633     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1634          C != E; ++C) {
1635       if (isChar6)
1636         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1637       if ((unsigned char)*C & 128) {
1638         is7Bit = false;
1639         break;  // don't bother scanning the rest.
1640       }
1641     }
1642
1643     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1644
1645     // VST_ENTRY:   [valueid, namechar x N]
1646     // VST_BBENTRY: [bbid, namechar x N]
1647     unsigned Code;
1648     if (isa<BasicBlock>(SI->getValue())) {
1649       Code = bitc::VST_CODE_BBENTRY;
1650       if (isChar6)
1651         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1652     } else {
1653       Code = bitc::VST_CODE_ENTRY;
1654       if (isChar6)
1655         AbbrevToUse = VST_ENTRY_6_ABBREV;
1656       else if (is7Bit)
1657         AbbrevToUse = VST_ENTRY_7_ABBREV;
1658     }
1659
1660     NameVals.push_back(VE.getValueID(SI->getValue()));
1661     for (const char *P = Name.getKeyData(),
1662          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1663       NameVals.push_back((unsigned char)*P);
1664
1665     // Emit the finished record.
1666     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1667     NameVals.clear();
1668   }
1669   Stream.ExitBlock();
1670 }
1671
1672 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1673                          BitstreamWriter &Stream) {
1674   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1675   unsigned Code;
1676   if (isa<BasicBlock>(Order.V))
1677     Code = bitc::USELIST_CODE_BB;
1678   else
1679     Code = bitc::USELIST_CODE_DEFAULT;
1680
1681   SmallVector<uint64_t, 64> Record;
1682   for (unsigned I : Order.Shuffle)
1683     Record.push_back(I);
1684   Record.push_back(VE.getValueID(Order.V));
1685   Stream.EmitRecord(Code, Record);
1686 }
1687
1688 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1689                               BitstreamWriter &Stream) {
1690   auto hasMore = [&]() {
1691     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1692   };
1693   if (!hasMore())
1694     // Nothing to do.
1695     return;
1696
1697   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1698   while (hasMore()) {
1699     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1700     VE.UseListOrders.pop_back();
1701   }
1702   Stream.ExitBlock();
1703 }
1704
1705 /// WriteFunction - Emit a function body to the module stream.
1706 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1707                           BitstreamWriter &Stream) {
1708   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1709   VE.incorporateFunction(F);
1710
1711   SmallVector<unsigned, 64> Vals;
1712
1713   // Emit the number of basic blocks, so the reader can create them ahead of
1714   // time.
1715   Vals.push_back(VE.getBasicBlocks().size());
1716   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1717   Vals.clear();
1718
1719   // If there are function-local constants, emit them now.
1720   unsigned CstStart, CstEnd;
1721   VE.getFunctionConstantRange(CstStart, CstEnd);
1722   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1723
1724   // If there is function-local metadata, emit it now.
1725   WriteFunctionLocalMetadata(F, VE, Stream);
1726
1727   // Keep a running idea of what the instruction ID is.
1728   unsigned InstID = CstEnd;
1729
1730   bool NeedsMetadataAttachment = false;
1731
1732   DebugLoc LastDL;
1733
1734   // Finally, emit all the instructions, in order.
1735   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1736     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1737          I != E; ++I) {
1738       WriteInstruction(*I, InstID, VE, Stream, Vals);
1739
1740       if (!I->getType()->isVoidTy())
1741         ++InstID;
1742
1743       // If the instruction has metadata, write a metadata attachment later.
1744       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1745
1746       // If the instruction has a debug location, emit it.
1747       DebugLoc DL = I->getDebugLoc();
1748       if (DL.isUnknown()) {
1749         // nothing todo.
1750       } else if (DL == LastDL) {
1751         // Just repeat the same debug loc as last time.
1752         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1753       } else {
1754         MDNode *Scope, *IA;
1755         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1756         assert(Scope && "Expected valid scope");
1757
1758         Vals.push_back(DL.getLine());
1759         Vals.push_back(DL.getCol());
1760         Vals.push_back(VE.getMetadataOrNullID(Scope));
1761         Vals.push_back(VE.getMetadataOrNullID(IA));
1762         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1763         Vals.clear();
1764
1765         LastDL = DL;
1766       }
1767     }
1768
1769   // Emit names for all the instructions etc.
1770   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1771
1772   if (NeedsMetadataAttachment)
1773     WriteMetadataAttachment(F, VE, Stream);
1774   if (shouldPreserveBitcodeUseListOrder())
1775     WriteUseListBlock(&F, VE, Stream);
1776   VE.purgeFunction();
1777   Stream.ExitBlock();
1778 }
1779
1780 // Emit blockinfo, which defines the standard abbreviations etc.
1781 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1782   // We only want to emit block info records for blocks that have multiple
1783   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1784   // Other blocks can define their abbrevs inline.
1785   Stream.EnterBlockInfoBlock(2);
1786
1787   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1788     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1790     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1791     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1792     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1793     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1794                                    Abbv) != VST_ENTRY_8_ABBREV)
1795       llvm_unreachable("Unexpected abbrev ordering!");
1796   }
1797
1798   { // 7-bit fixed width VST_ENTRY strings.
1799     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1800     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1801     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1802     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1803     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1804     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1805                                    Abbv) != VST_ENTRY_7_ABBREV)
1806       llvm_unreachable("Unexpected abbrev ordering!");
1807   }
1808   { // 6-bit char6 VST_ENTRY strings.
1809     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1810     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1811     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1812     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1813     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1814     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1815                                    Abbv) != VST_ENTRY_6_ABBREV)
1816       llvm_unreachable("Unexpected abbrev ordering!");
1817   }
1818   { // 6-bit char6 VST_BBENTRY strings.
1819     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1820     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1821     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1822     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1823     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1824     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1825                                    Abbv) != VST_BBENTRY_6_ABBREV)
1826       llvm_unreachable("Unexpected abbrev ordering!");
1827   }
1828
1829
1830
1831   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1832     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1833     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1834     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1835                               Log2_32_Ceil(VE.getTypes().size()+1)));
1836     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1837                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1838       llvm_unreachable("Unexpected abbrev ordering!");
1839   }
1840
1841   { // INTEGER abbrev for CONSTANTS_BLOCK.
1842     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1843     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1844     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1845     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1846                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1847       llvm_unreachable("Unexpected abbrev ordering!");
1848   }
1849
1850   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1851     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1852     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1853     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1854     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1855                               Log2_32_Ceil(VE.getTypes().size()+1)));
1856     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1857
1858     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1859                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1860       llvm_unreachable("Unexpected abbrev ordering!");
1861   }
1862   { // NULL abbrev for CONSTANTS_BLOCK.
1863     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1864     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1865     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1866                                    Abbv) != CONSTANTS_NULL_Abbrev)
1867       llvm_unreachable("Unexpected abbrev ordering!");
1868   }
1869
1870   // FIXME: This should only use space for first class types!
1871
1872   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1873     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1874     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1875     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1876     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1877     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1878     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1879                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1880       llvm_unreachable("Unexpected abbrev ordering!");
1881   }
1882   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1883     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1884     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1885     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1886     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1887     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1888     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1889                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1890       llvm_unreachable("Unexpected abbrev ordering!");
1891   }
1892   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1893     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1894     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1895     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1897     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1898     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1899     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1900                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1901       llvm_unreachable("Unexpected abbrev ordering!");
1902   }
1903   { // INST_CAST abbrev for FUNCTION_BLOCK.
1904     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1905     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1906     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1907     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1908                               Log2_32_Ceil(VE.getTypes().size()+1)));
1909     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1910     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1911                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1912       llvm_unreachable("Unexpected abbrev ordering!");
1913   }
1914
1915   { // INST_RET abbrev for FUNCTION_BLOCK.
1916     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1917     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1918     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1919                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1920       llvm_unreachable("Unexpected abbrev ordering!");
1921   }
1922   { // INST_RET abbrev for FUNCTION_BLOCK.
1923     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1924     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1925     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1926     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1927                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1928       llvm_unreachable("Unexpected abbrev ordering!");
1929   }
1930   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1931     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1932     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1933     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1934                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1935       llvm_unreachable("Unexpected abbrev ordering!");
1936   }
1937
1938   Stream.ExitBlock();
1939 }
1940
1941 /// WriteModule - Emit the specified module to the bitstream.
1942 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1943   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1944
1945   SmallVector<unsigned, 1> Vals;
1946   unsigned CurVersion = 1;
1947   Vals.push_back(CurVersion);
1948   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1949
1950   // Analyze the module, enumerating globals, functions, etc.
1951   ValueEnumerator VE(*M);
1952
1953   // Emit blockinfo, which defines the standard abbreviations etc.
1954   WriteBlockInfo(VE, Stream);
1955
1956   // Emit information about attribute groups.
1957   WriteAttributeGroupTable(VE, Stream);
1958
1959   // Emit information about parameter attributes.
1960   WriteAttributeTable(VE, Stream);
1961
1962   // Emit information describing all of the types in the module.
1963   WriteTypeTable(VE, Stream);
1964
1965   writeComdats(VE, Stream);
1966
1967   // Emit top-level description of module, including target triple, inline asm,
1968   // descriptors for global variables, and function prototype info.
1969   WriteModuleInfo(M, VE, Stream);
1970
1971   // Emit constants.
1972   WriteModuleConstants(VE, Stream);
1973
1974   // Emit metadata.
1975   WriteModuleMetadata(M, VE, Stream);
1976
1977   // Emit metadata.
1978   WriteModuleMetadataStore(M, Stream);
1979
1980   // Emit names for globals/functions etc.
1981   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1982
1983   // Emit module-level use-lists.
1984   if (shouldPreserveBitcodeUseListOrder())
1985     WriteUseListBlock(nullptr, VE, Stream);
1986
1987   // Emit function bodies.
1988   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1989     if (!F->isDeclaration())
1990       WriteFunction(*F, VE, Stream);
1991
1992   Stream.ExitBlock();
1993 }
1994
1995 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1996 /// header and trailer to make it compatible with the system archiver.  To do
1997 /// this we emit the following header, and then emit a trailer that pads the
1998 /// file out to be a multiple of 16 bytes.
1999 ///
2000 /// struct bc_header {
2001 ///   uint32_t Magic;         // 0x0B17C0DE
2002 ///   uint32_t Version;       // Version, currently always 0.
2003 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2004 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2005 ///   uint32_t CPUType;       // CPU specifier.
2006 ///   ... potentially more later ...
2007 /// };
2008 enum {
2009   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2010   DarwinBCHeaderSize = 5*4
2011 };
2012
2013 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2014                                uint32_t &Position) {
2015   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2016   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2017   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2018   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2019   Position += 4;
2020 }
2021
2022 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2023                                          const Triple &TT) {
2024   unsigned CPUType = ~0U;
2025
2026   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2027   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2028   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2029   // specific constants here because they are implicitly part of the Darwin ABI.
2030   enum {
2031     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2032     DARWIN_CPU_TYPE_X86        = 7,
2033     DARWIN_CPU_TYPE_ARM        = 12,
2034     DARWIN_CPU_TYPE_POWERPC    = 18
2035   };
2036
2037   Triple::ArchType Arch = TT.getArch();
2038   if (Arch == Triple::x86_64)
2039     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2040   else if (Arch == Triple::x86)
2041     CPUType = DARWIN_CPU_TYPE_X86;
2042   else if (Arch == Triple::ppc)
2043     CPUType = DARWIN_CPU_TYPE_POWERPC;
2044   else if (Arch == Triple::ppc64)
2045     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2046   else if (Arch == Triple::arm || Arch == Triple::thumb)
2047     CPUType = DARWIN_CPU_TYPE_ARM;
2048
2049   // Traditional Bitcode starts after header.
2050   assert(Buffer.size() >= DarwinBCHeaderSize &&
2051          "Expected header size to be reserved");
2052   unsigned BCOffset = DarwinBCHeaderSize;
2053   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2054
2055   // Write the magic and version.
2056   unsigned Position = 0;
2057   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2058   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2059   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2060   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2061   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2062
2063   // If the file is not a multiple of 16 bytes, insert dummy padding.
2064   while (Buffer.size() & 15)
2065     Buffer.push_back(0);
2066 }
2067
2068 /// WriteBitcodeToFile - Write the specified module to the specified output
2069 /// stream.
2070 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2071   SmallVector<char, 0> Buffer;
2072   Buffer.reserve(256*1024);
2073
2074   // If this is darwin or another generic macho target, reserve space for the
2075   // header.
2076   Triple TT(M->getTargetTriple());
2077   if (TT.isOSDarwin())
2078     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2079
2080   // Emit the module into the buffer.
2081   {
2082     BitstreamWriter Stream(Buffer);
2083
2084     // Emit the file header.
2085     Stream.Emit((unsigned)'B', 8);
2086     Stream.Emit((unsigned)'C', 8);
2087     Stream.Emit(0x0, 4);
2088     Stream.Emit(0xC, 4);
2089     Stream.Emit(0xE, 4);
2090     Stream.Emit(0xD, 4);
2091
2092     // Emit the module.
2093     WriteModule(M, Stream);
2094   }
2095
2096   if (TT.isOSDarwin())
2097     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2098
2099   // Write the generated bitstream to "Out".
2100   Out.write((char*)&Buffer.front(), Buffer.size());
2101 }