lib/Bitcode/Writer/BitcodeWriter.cpp

   1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Bitcode writer implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Bitcode/ReaderWriter.h"
  15 #include "ValueEnumerator.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Bitcode/BitstreamWriter.h"
  18 #include "llvm/Bitcode/LLVMBitCodes.h"
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DebugInfoMetadata.h"
  21 #include "llvm/IR/DerivedTypes.h"
  22 #include "llvm/IR/InlineAsm.h"
  23 #include "llvm/IR/Instructions.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/IR/Operator.h"
  26 #include "llvm/IR/UseListOrder.h"
  27 #include "llvm/IR/ValueSymbolTable.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/MathExtras.h"
  31 #include "llvm/Support/Program.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 #include <cctype>
  34 #include <map>
  35 using namespace llvm;
  36
  37 /// These are manifest constants used by the bitcode writer. They do not need to
  38 /// be kept in sync with the reader, but need to be consistent within this file.
  39 enum {
  40   // VALUE_SYMTAB_BLOCK abbrev id's.
  41   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  42   VST_ENTRY_7_ABBREV,
  43   VST_ENTRY_6_ABBREV,
  44   VST_BBENTRY_6_ABBREV,
  45
  46   // CONSTANTS_BLOCK abbrev id's.
  47   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   CONSTANTS_INTEGER_ABBREV,
  49   CONSTANTS_CE_CAST_Abbrev,
  50   CONSTANTS_NULL_Abbrev,
  51
  52   // FUNCTION_BLOCK abbrev id's.
  53   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   FUNCTION_INST_BINOP_ABBREV,
  55   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  56   FUNCTION_INST_CAST_ABBREV,
  57   FUNCTION_INST_RET_VOID_ABBREV,
  58   FUNCTION_INST_RET_VAL_ABBREV,
  59   FUNCTION_INST_UNREACHABLE_ABBREV
  60 };
  61
  62 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  63   switch (Opcode) {
  64   default: llvm_unreachable("Unknown cast instruction!");
  65   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  66   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  67   case Instruction::SExt    : return bitc::CAST_SEXT;
  68   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  69   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  70   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  71   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  72   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  73   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  74   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  75   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  76   case Instruction::BitCast : return bitc::CAST_BITCAST;
  77   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
  78   }
  79 }
  80
  81 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  82   switch (Opcode) {
  83   default: llvm_unreachable("Unknown binary instruction!");
  84   case Instruction::Add:
  85   case Instruction::FAdd: return bitc::BINOP_ADD;
  86   case Instruction::Sub:
  87   case Instruction::FSub: return bitc::BINOP_SUB;
  88   case Instruction::Mul:
  89   case Instruction::FMul: return bitc::BINOP_MUL;
  90   case Instruction::UDiv: return bitc::BINOP_UDIV;
  91   case Instruction::FDiv:
  92   case Instruction::SDiv: return bitc::BINOP_SDIV;
  93   case Instruction::URem: return bitc::BINOP_UREM;
  94   case Instruction::FRem:
  95   case Instruction::SRem: return bitc::BINOP_SREM;
  96   case Instruction::Shl:  return bitc::BINOP_SHL;
  97   case Instruction::LShr: return bitc::BINOP_LSHR;
  98   case Instruction::AShr: return bitc::BINOP_ASHR;
  99   case Instruction::And:  return bitc::BINOP_AND;
 100   case Instruction::Or:   return bitc::BINOP_OR;
 101   case Instruction::Xor:  return bitc::BINOP_XOR;
 102   }
 103 }
 104
 105 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 106   switch (Op) {
 107   default: llvm_unreachable("Unknown RMW operation!");
 108   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 109   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 110   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 111   case AtomicRMWInst::And: return bitc::RMW_AND;
 112   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 113   case AtomicRMWInst::Or: return bitc::RMW_OR;
 114   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 115   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 116   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 117   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 118   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 119   }
 120 }
 121
 122 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 123   switch (Ordering) {
 124   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 125   case Unordered: return bitc::ORDERING_UNORDERED;
 126   case Monotonic: return bitc::ORDERING_MONOTONIC;
 127   case Acquire: return bitc::ORDERING_ACQUIRE;
 128   case Release: return bitc::ORDERING_RELEASE;
 129   case AcquireRelease: return bitc::ORDERING_ACQREL;
 130   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 131   }
 132   llvm_unreachable("Invalid ordering");
 133 }
 134
 135 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 136   switch (SynchScope) {
 137   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 138   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 139   }
 140   llvm_unreachable("Invalid synch scope");
 141 }
 142
 143 static void WriteStringRecord(unsigned Code, StringRef Str,
 144                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 145   SmallVector<unsigned, 64> Vals;
 146
 147   // Code: [strchar x N]
 148   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 149     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 150       AbbrevToUse = 0;
 151     Vals.push_back(Str[i]);
 152   }
 153
 154   // Emit the finished record.
 155   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 156 }
 157
 158 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
 159   switch (Kind) {
 160   case Attribute::Alignment:
 161     return bitc::ATTR_KIND_ALIGNMENT;
 162   case Attribute::AlwaysInline:
 163     return bitc::ATTR_KIND_ALWAYS_INLINE;
 164   case Attribute::Builtin:
 165     return bitc::ATTR_KIND_BUILTIN;
 166   case Attribute::ByVal:
 167     return bitc::ATTR_KIND_BY_VAL;
 168   case Attribute::InAlloca:
 169     return bitc::ATTR_KIND_IN_ALLOCA;
 170   case Attribute::Cold:
 171     return bitc::ATTR_KIND_COLD;
 172   case Attribute::InlineHint:
 173     return bitc::ATTR_KIND_INLINE_HINT;
 174   case Attribute::InReg:
 175     return bitc::ATTR_KIND_IN_REG;
 176   case Attribute::JumpTable:
 177     return bitc::ATTR_KIND_JUMP_TABLE;
 178   case Attribute::MinSize:
 179     return bitc::ATTR_KIND_MIN_SIZE;
 180   case Attribute::Naked:
 181     return bitc::ATTR_KIND_NAKED;
 182   case Attribute::Nest:
 183     return bitc::ATTR_KIND_NEST;
 184   case Attribute::NoAlias:
 185     return bitc::ATTR_KIND_NO_ALIAS;
 186   case Attribute::NoBuiltin:
 187     return bitc::ATTR_KIND_NO_BUILTIN;
 188   case Attribute::NoCapture:
 189     return bitc::ATTR_KIND_NO_CAPTURE;
 190   case Attribute::NoDuplicate:
 191     return bitc::ATTR_KIND_NO_DUPLICATE;
 192   case Attribute::NoImplicitFloat:
 193     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
 194   case Attribute::NoInline:
 195     return bitc::ATTR_KIND_NO_INLINE;
 196   case Attribute::NonLazyBind:
 197     return bitc::ATTR_KIND_NON_LAZY_BIND;
 198   case Attribute::NonNull:
 199     return bitc::ATTR_KIND_NON_NULL;
 200   case Attribute::Dereferenceable:
 201     return bitc::ATTR_KIND_DEREFERENCEABLE;
 202   case Attribute::NoRedZone:
 203     return bitc::ATTR_KIND_NO_RED_ZONE;
 204   case Attribute::NoReturn:
 205     return bitc::ATTR_KIND_NO_RETURN;
 206   case Attribute::NoUnwind:
 207     return bitc::ATTR_KIND_NO_UNWIND;
 208   case Attribute::OptimizeForSize:
 209     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
 210   case Attribute::OptimizeNone:
 211     return bitc::ATTR_KIND_OPTIMIZE_NONE;
 212   case Attribute::ReadNone:
 213     return bitc::ATTR_KIND_READ_NONE;
 214   case Attribute::ReadOnly:
 215     return bitc::ATTR_KIND_READ_ONLY;
 216   case Attribute::Returned:
 217     return bitc::ATTR_KIND_RETURNED;
 218   case Attribute::ReturnsTwice:
 219     return bitc::ATTR_KIND_RETURNS_TWICE;
 220   case Attribute::SExt:
 221     return bitc::ATTR_KIND_S_EXT;
 222   case Attribute::StackAlignment:
 223     return bitc::ATTR_KIND_STACK_ALIGNMENT;
 224   case Attribute::StackProtect:
 225     return bitc::ATTR_KIND_STACK_PROTECT;
 226   case Attribute::StackProtectReq:
 227     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
 228   case Attribute::StackProtectStrong:
 229     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
 230   case Attribute::StructRet:
 231     return bitc::ATTR_KIND_STRUCT_RET;
 232   case Attribute::SanitizeAddress:
 233     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
 234   case Attribute::SanitizeThread:
 235     return bitc::ATTR_KIND_SANITIZE_THREAD;
 236   case Attribute::SanitizeMemory:
 237     return bitc::ATTR_KIND_SANITIZE_MEMORY;
 238   case Attribute::UWTable:
 239     return bitc::ATTR_KIND_UW_TABLE;
 240   case Attribute::ZExt:
 241     return bitc::ATTR_KIND_Z_EXT;
 242   case Attribute::EndAttrKinds:
 243     llvm_unreachable("Can not encode end-attribute kinds marker.");
 244   case Attribute::None:
 245     llvm_unreachable("Can not encode none-attribute.");
 246   }
 247
 248   llvm_unreachable("Trying to encode unknown attribute");
 249 }
 250
 251 static void WriteAttributeGroupTable(const ValueEnumerator &VE,
 252                                      BitstreamWriter &Stream) {
 253   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
 254   if (AttrGrps.empty()) return;
 255
 256   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 257
 258   SmallVector<uint64_t, 64> Record;
 259   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
 260     AttributeSet AS = AttrGrps[i];
 261     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
 262       AttributeSet A = AS.getSlotAttributes(i);
 263
 264       Record.push_back(VE.getAttributeGroupID(A));
 265       Record.push_back(AS.getSlotIndex(i));
 266
 267       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
 268            I != E; ++I) {
 269         Attribute Attr = *I;
 270         if (Attr.isEnumAttribute()) {
 271           Record.push_back(0);
 272           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 273         } else if (Attr.isIntAttribute()) {
 274           Record.push_back(1);
 275           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
 276           Record.push_back(Attr.getValueAsInt());
 277         } else {
 278           StringRef Kind = Attr.getKindAsString();
 279           StringRef Val = Attr.getValueAsString();
 280
 281           Record.push_back(Val.empty() ? 3 : 4);
 282           Record.append(Kind.begin(), Kind.end());
 283           Record.push_back(0);
 284           if (!Val.empty()) {
 285             Record.append(Val.begin(), Val.end());
 286             Record.push_back(0);
 287           }
 288         }
 289       }
 290
 291       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
 292       Record.clear();
 293     }
 294   }
 295
 296   Stream.ExitBlock();
 297 }
 298
 299 static void WriteAttributeTable(const ValueEnumerator &VE,
 300                                 BitstreamWriter &Stream) {
 301   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
 302   if (Attrs.empty()) return;
 303
 304   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 305
 306   SmallVector<uint64_t, 64> Record;
 307   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 308     const AttributeSet &A = Attrs[i];
 309     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
 310       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 311
 312     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 313     Record.clear();
 314   }
 315
 316   Stream.ExitBlock();
 317 }
 318
 319 /// WriteTypeTable - Write out the type table for a module.
 320 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 321   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 322
 323   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 324   SmallVector<uint64_t, 64> TypeVals;
 325
 326   uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
 327
 328   // Abbrev for TYPE_CODE_POINTER.
 329   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 330   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 332   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 333   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 334
 335   // Abbrev for TYPE_CODE_FUNCTION.
 336   Abbv = new BitCodeAbbrev();
 337   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 339   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 341
 342   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 343
 344   // Abbrev for TYPE_CODE_STRUCT_ANON.
 345   Abbv = new BitCodeAbbrev();
 346   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 348   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 349   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 350
 351   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 352
 353   // Abbrev for TYPE_CODE_STRUCT_NAME.
 354   Abbv = new BitCodeAbbrev();
 355   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 358   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 359
 360   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 361   Abbv = new BitCodeAbbrev();
 362   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 366
 367   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 368
 369   // Abbrev for TYPE_CODE_ARRAY.
 370   Abbv = new BitCodeAbbrev();
 371   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 373   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
 374
 375   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 376
 377   // Emit an entry count so the reader can reserve space.
 378   TypeVals.push_back(TypeList.size());
 379   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 380   TypeVals.clear();
 381
 382   // Loop over all of the types, emitting each in turn.
 383   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 384     Type *T = TypeList[i];
 385     int AbbrevToUse = 0;
 386     unsigned Code = 0;
 387
 388     switch (T->getTypeID()) {
 389     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
 390     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
 391     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
 392     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
 393     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
 394     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
 395     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 396     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
 397     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
 398     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
 399     case Type::IntegerTyID:
 400       // INTEGER: [width]
 401       Code = bitc::TYPE_CODE_INTEGER;
 402       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 403       break;
 404     case Type::PointerTyID: {
 405       PointerType *PTy = cast<PointerType>(T);
 406       // POINTER: [pointee type, address space]
 407       Code = bitc::TYPE_CODE_POINTER;
 408       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 409       unsigned AddressSpace = PTy->getAddressSpace();
 410       TypeVals.push_back(AddressSpace);
 411       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 412       break;
 413     }
 414     case Type::FunctionTyID: {
 415       FunctionType *FT = cast<FunctionType>(T);
 416       // FUNCTION: [isvararg, retty, paramty x N]
 417       Code = bitc::TYPE_CODE_FUNCTION;
 418       TypeVals.push_back(FT->isVarArg());
 419       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 420       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 421         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 422       AbbrevToUse = FunctionAbbrev;
 423       break;
 424     }
 425     case Type::StructTyID: {
 426       StructType *ST = cast<StructType>(T);
 427       // STRUCT: [ispacked, eltty x N]
 428       TypeVals.push_back(ST->isPacked());
 429       // Output all of the element types.
 430       for (StructType::element_iterator I = ST->element_begin(),
 431            E = ST->element_end(); I != E; ++I)
 432         TypeVals.push_back(VE.getTypeID(*I));
 433
 434       if (ST->isLiteral()) {
 435         Code = bitc::TYPE_CODE_STRUCT_ANON;
 436         AbbrevToUse = StructAnonAbbrev;
 437       } else {
 438         if (ST->isOpaque()) {
 439           Code = bitc::TYPE_CODE_OPAQUE;
 440         } else {
 441           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 442           AbbrevToUse = StructNamedAbbrev;
 443         }
 444
 445         // Emit the name if it is present.
 446         if (!ST->getName().empty())
 447           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 448                             StructNameAbbrev, Stream);
 449       }
 450       break;
 451     }
 452     case Type::ArrayTyID: {
 453       ArrayType *AT = cast<ArrayType>(T);
 454       // ARRAY: [numelts, eltty]
 455       Code = bitc::TYPE_CODE_ARRAY;
 456       TypeVals.push_back(AT->getNumElements());
 457       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 458       AbbrevToUse = ArrayAbbrev;
 459       break;
 460     }
 461     case Type::VectorTyID: {
 462       VectorType *VT = cast<VectorType>(T);
 463       // VECTOR [numelts, eltty]
 464       Code = bitc::TYPE_CODE_VECTOR;
 465       TypeVals.push_back(VT->getNumElements());
 466       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 467       break;
 468     }
 469     }
 470
 471     // Emit the finished record.
 472     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 473     TypeVals.clear();
 474   }
 475
 476   Stream.ExitBlock();
 477 }
 478
 479 static unsigned getEncodedLinkage(const GlobalValue &GV) {
 480   switch (GV.getLinkage()) {
 481   case GlobalValue::ExternalLinkage:
 482     return 0;
 483   case GlobalValue::WeakAnyLinkage:
 484     return 16;
 485   case GlobalValue::AppendingLinkage:
 486     return 2;
 487   case GlobalValue::InternalLinkage:
 488     return 3;
 489   case GlobalValue::LinkOnceAnyLinkage:
 490     return 18;
 491   case GlobalValue::ExternalWeakLinkage:
 492     return 7;
 493   case GlobalValue::CommonLinkage:
 494     return 8;
 495   case GlobalValue::PrivateLinkage:
 496     return 9;
 497   case GlobalValue::WeakODRLinkage:
 498     return 17;
 499   case GlobalValue::LinkOnceODRLinkage:
 500     return 19;
 501   case GlobalValue::AvailableExternallyLinkage:
 502     return 12;
 503   }
 504   llvm_unreachable("Invalid linkage");
 505 }
 506
 507 static unsigned getEncodedVisibility(const GlobalValue &GV) {
 508   switch (GV.getVisibility()) {
 509   case GlobalValue::DefaultVisibility:   return 0;
 510   case GlobalValue::HiddenVisibility:    return 1;
 511   case GlobalValue::ProtectedVisibility: return 2;
 512   }
 513   llvm_unreachable("Invalid visibility");
 514 }
 515
 516 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
 517   switch (GV.getDLLStorageClass()) {
 518   case GlobalValue::DefaultStorageClass:   return 0;
 519   case GlobalValue::DLLImportStorageClass: return 1;
 520   case GlobalValue::DLLExportStorageClass: return 2;
 521   }
 522   llvm_unreachable("Invalid DLL storage class");
 523 }
 524
 525 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
 526   switch (GV.getThreadLocalMode()) {
 527     case GlobalVariable::NotThreadLocal:         return 0;
 528     case GlobalVariable::GeneralDynamicTLSModel: return 1;
 529     case GlobalVariable::LocalDynamicTLSModel:   return 2;
 530     case GlobalVariable::InitialExecTLSModel:    return 3;
 531     case GlobalVariable::LocalExecTLSModel:      return 4;
 532   }
 533   llvm_unreachable("Invalid TLS model");
 534 }
 535
 536 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
 537   switch (C.getSelectionKind()) {
 538   case Comdat::Any:
 539     return bitc::COMDAT_SELECTION_KIND_ANY;
 540   case Comdat::ExactMatch:
 541     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
 542   case Comdat::Largest:
 543     return bitc::COMDAT_SELECTION_KIND_LARGEST;
 544   case Comdat::NoDuplicates:
 545     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
 546   case Comdat::SameSize:
 547     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
 548   }
 549   llvm_unreachable("Invalid selection kind");
 550 }
 551
 552 static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 553   SmallVector<uint16_t, 64> Vals;
 554   for (const Comdat *C : VE.getComdats()) {
 555     // COMDAT: [selection_kind, name]
 556     Vals.push_back(getEncodedComdatSelectionKind(*C));
 557     size_t Size = C->getName().size();
 558     assert(isUInt<16>(Size));
 559     Vals.push_back(Size);
 560     for (char Chr : C->getName())
 561       Vals.push_back((unsigned char)Chr);
 562     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 563     Vals.clear();
 564   }
 565 }
 566
 567 // Emit top-level description of module, including target triple, inline asm,
 568 // descriptors for global variables, and function prototype info.
 569 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 570                             BitstreamWriter &Stream) {
 571   // Emit various pieces of data attached to a module.
 572   if (!M->getTargetTriple().empty())
 573     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 574                       0/*TODO*/, Stream);
 575   const std::string &DL = M->getDataLayoutStr();
 576   if (!DL.empty())
 577     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 578   if (!M->getModuleInlineAsm().empty())
 579     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 580                       0/*TODO*/, Stream);
 581
 582   // Emit information about sections and GC, computing how many there are. Also
 583   // compute the maximum alignment value.
 584   std::map<std::string, unsigned> SectionMap;
 585   std::map<std::string, unsigned> GCMap;
 586   unsigned MaxAlignment = 0;
 587   unsigned MaxGlobalType = 0;
 588   for (const GlobalValue &GV : M->globals()) {
 589     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 590     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 591     if (GV.hasSection()) {
 592       // Give section names unique ID's.
 593       unsigned &Entry = SectionMap[GV.getSection()];
 594       if (!Entry) {
 595         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 596                           0/*TODO*/, Stream);
 597         Entry = SectionMap.size();
 598       }
 599     }
 600   }
 601   for (const Function &F : *M) {
 602     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 603     if (F.hasSection()) {
 604       // Give section names unique ID's.
 605       unsigned &Entry = SectionMap[F.getSection()];
 606       if (!Entry) {
 607         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 608                           0/*TODO*/, Stream);
 609         Entry = SectionMap.size();
 610       }
 611     }
 612     if (F.hasGC()) {
 613       // Same for GC names.
 614       unsigned &Entry = GCMap[F.getGC()];
 615       if (!Entry) {
 616         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 617                           0/*TODO*/, Stream);
 618         Entry = GCMap.size();
 619       }
 620     }
 621   }
 622
 623   // Emit abbrev for globals, now that we know # sections and max alignment.
 624   unsigned SimpleGVarAbbrev = 0;
 625   if (!M->global_empty()) {
 626     // Add an abbrev for common globals with no visibility or thread localness.
 627     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 628     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 629     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 630                               Log2_32_Ceil(MaxGlobalType+1)));
 631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5));      // Linkage.
 634     if (MaxAlignment == 0)                                      // Alignment.
 635       Abbv->Add(BitCodeAbbrevOp(0));
 636     else {
 637       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 638       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 639                                Log2_32_Ceil(MaxEncAlignment+1)));
 640     }
 641     if (SectionMap.empty())                                    // Section.
 642       Abbv->Add(BitCodeAbbrevOp(0));
 643     else
 644       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 645                                Log2_32_Ceil(SectionMap.size()+1)));
 646     // Don't bother emitting vis + thread local.
 647     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 648   }
 649
 650   // Emit the global variable information.
 651   SmallVector<unsigned, 64> Vals;
 652   for (const GlobalVariable &GV : M->globals()) {
 653     unsigned AbbrevToUse = 0;
 654
 655     // GLOBALVAR: [type, isconst, initid,
 656     //             linkage, alignment, section, visibility, threadlocal,
 657     //             unnamed_addr, externally_initialized, dllstorageclass,
 658     //             comdat]
 659     Vals.push_back(VE.getTypeID(GV.getType()));
 660     Vals.push_back(GV.isConstant());
 661     Vals.push_back(GV.isDeclaration() ? 0 :
 662                    (VE.getValueID(GV.getInitializer()) + 1));
 663     Vals.push_back(getEncodedLinkage(GV));
 664     Vals.push_back(Log2_32(GV.getAlignment())+1);
 665     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 666     if (GV.isThreadLocal() ||
 667         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 668         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 669         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 670         GV.hasComdat()) {
 671       Vals.push_back(getEncodedVisibility(GV));
 672       Vals.push_back(getEncodedThreadLocalMode(GV));
 673       Vals.push_back(GV.hasUnnamedAddr());
 674       Vals.push_back(GV.isExternallyInitialized());
 675       Vals.push_back(getEncodedDLLStorageClass(GV));
 676       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 677     } else {
 678       AbbrevToUse = SimpleGVarAbbrev;
 679     }
 680
 681     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 682     Vals.clear();
 683   }
 684
 685   // Emit the function proto information.
 686   for (const Function &F : *M) {
 687     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 688     //             section, visibility, gc, unnamed_addr, prologuedata,
 689     //             dllstorageclass, comdat, prefixdata]
 690     Vals.push_back(VE.getTypeID(F.getType()));
 691     Vals.push_back(F.getCallingConv());
 692     Vals.push_back(F.isDeclaration());
 693     Vals.push_back(getEncodedLinkage(F));
 694     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 695     Vals.push_back(Log2_32(F.getAlignment())+1);
 696     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 697     Vals.push_back(getEncodedVisibility(F));
 698     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 699     Vals.push_back(F.hasUnnamedAddr());
 700     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 701                                        : 0);
 702     Vals.push_back(getEncodedDLLStorageClass(F));
 703     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 704     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 705                                      : 0);
 706
 707     unsigned AbbrevToUse = 0;
 708     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 709     Vals.clear();
 710   }
 711
 712   // Emit the alias information.
 713   for (const GlobalAlias &A : M->aliases()) {
 714     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 715     Vals.push_back(VE.getTypeID(A.getType()));
 716     Vals.push_back(VE.getValueID(A.getAliasee()));
 717     Vals.push_back(getEncodedLinkage(A));
 718     Vals.push_back(getEncodedVisibility(A));
 719     Vals.push_back(getEncodedDLLStorageClass(A));
 720     Vals.push_back(getEncodedThreadLocalMode(A));
 721     Vals.push_back(A.hasUnnamedAddr());
 722     unsigned AbbrevToUse = 0;
 723     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 724     Vals.clear();
 725   }
 726 }
 727
 728 static uint64_t GetOptimizationFlags(const Value *V) {
 729   uint64_t Flags = 0;
 730
 731   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 732     if (OBO->hasNoSignedWrap())
 733       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 734     if (OBO->hasNoUnsignedWrap())
 735       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 736   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 737     if (PEO->isExact())
 738       Flags |= 1 << bitc::PEO_EXACT;
 739   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 740     if (FPMO->hasUnsafeAlgebra())
 741       Flags |= FastMathFlags::UnsafeAlgebra;
 742     if (FPMO->hasNoNaNs())
 743       Flags |= FastMathFlags::NoNaNs;
 744     if (FPMO->hasNoInfs())
 745       Flags |= FastMathFlags::NoInfs;
 746     if (FPMO->hasNoSignedZeros())
 747       Flags |= FastMathFlags::NoSignedZeros;
 748     if (FPMO->hasAllowReciprocal())
 749       Flags |= FastMathFlags::AllowReciprocal;
 750   }
 751
 752   return Flags;
 753 }
 754
 755 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 756                                  const ValueEnumerator &VE,
 757                                  BitstreamWriter &Stream,
 758                                  SmallVectorImpl<uint64_t> &Record) {
 759   // Mimic an MDNode with a value as one operand.
 760   Value *V = MD->getValue();
 761   Record.push_back(VE.getTypeID(V->getType()));
 762   Record.push_back(VE.getValueID(V));
 763   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 764   Record.clear();
 765 }
 766
 767 static void WriteMDTuple(const MDTuple *N, const ValueEnumerator &VE,
 768                          BitstreamWriter &Stream,
 769                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev) {
 770   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 771     Metadata *MD = N->getOperand(i);
 772     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
 773            "Unexpected function-local metadata");
 774     Record.push_back(VE.getMetadataOrNullID(MD));
 775   }
 776   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 777                                     : bitc::METADATA_NODE,
 778                     Record, Abbrev);
 779   Record.clear();
 780 }
 781
 782 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 783                             BitstreamWriter &Stream,
 784                             SmallVectorImpl<uint64_t> &Record,
 785                             unsigned Abbrev) {
 786   Record.push_back(N->isDistinct());
 787   Record.push_back(N->getLine());
 788   Record.push_back(N->getColumn());
 789   Record.push_back(VE.getMetadataID(N->getScope()));
 790   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
 791
 792   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 793   Record.clear();
 794 }
 795
 796 static void WriteGenericDebugNode(const GenericDebugNode *N,
 797                                   const ValueEnumerator &VE,
 798                                   BitstreamWriter &Stream,
 799                                   SmallVectorImpl<uint64_t> &Record,
 800                                   unsigned Abbrev) {
 801   Record.push_back(N->isDistinct());
 802   Record.push_back(N->getTag());
 803   Record.push_back(0); // Per-tag version field; unused for now.
 804
 805   for (auto &I : N->operands())
 806     Record.push_back(VE.getMetadataOrNullID(I));
 807
 808   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
 809   Record.clear();
 810 }
 811
 812 static uint64_t rotateSign(int64_t I) {
 813   uint64_t U = I;
 814   return I < 0 ? ~(U << 1) : U << 1;
 815 }
 816
 817 static void WriteMDSubrange(const MDSubrange *N, const ValueEnumerator &,
 818                             BitstreamWriter &Stream,
 819                             SmallVectorImpl<uint64_t> &Record,
 820                             unsigned Abbrev) {
 821   Record.push_back(N->isDistinct());
 822   Record.push_back(N->getCount());
 823   Record.push_back(rotateSign(N->getLo()));
 824
 825   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
 826   Record.clear();
 827 }
 828
 829 static void WriteMDEnumerator(const MDEnumerator *N, const ValueEnumerator &VE,
 830                               BitstreamWriter &Stream,
 831                               SmallVectorImpl<uint64_t> &Record,
 832                               unsigned Abbrev) {
 833   Record.push_back(N->isDistinct());
 834   Record.push_back(rotateSign(N->getValue()));
 835   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 836
 837   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
 838   Record.clear();
 839 }
 840
 841 static void WriteMDBasicType(const MDBasicType *N, const ValueEnumerator &VE,
 842                              BitstreamWriter &Stream,
 843                              SmallVectorImpl<uint64_t> &Record,
 844                              unsigned Abbrev) {
 845   Record.push_back(N->isDistinct());
 846   Record.push_back(N->getTag());
 847   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
 848   Record.push_back(N->getSizeInBits());
 849   Record.push_back(N->getAlignInBits());
 850   Record.push_back(N->getEncoding());
 851
 852   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
 853   Record.clear();
 854 }
 855
 856 static void WriteMDDerivedType(const MDDerivedType *, const ValueEnumerator &,
 857                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 858                                unsigned) {
 859   llvm_unreachable("write not implemented");
 860 }
 861 static void WriteMDCompositeType(const MDCompositeType *,
 862                                  const ValueEnumerator &, BitstreamWriter &,
 863                                  SmallVectorImpl<uint64_t> &, unsigned) {
 864   llvm_unreachable("write not implemented");
 865 }
 866 static void WriteMDSubroutineType(const MDSubroutineType *,
 867                                   const ValueEnumerator &, BitstreamWriter &,
 868                                   SmallVectorImpl<uint64_t> &, unsigned) {
 869   llvm_unreachable("write not implemented");
 870 }
 871 static void WriteMDFile(const MDFile *, const ValueEnumerator &,
 872                         BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 873                         unsigned) {
 874   llvm_unreachable("write not implemented");
 875 }
 876 static void WriteMDCompileUnit(const MDCompileUnit *, const ValueEnumerator &,
 877                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 878                                unsigned) {
 879   llvm_unreachable("write not implemented");
 880 }
 881 static void WriteMDSubprogram(const MDSubprogram *, const ValueEnumerator &,
 882                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 883                               unsigned) {
 884   llvm_unreachable("write not implemented");
 885 }
 886 static void WriteMDLexicalBlock(const MDLexicalBlock *, const ValueEnumerator &,
 887                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 888                                 unsigned) {
 889   llvm_unreachable("write not implemented");
 890 }
 891 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *,
 892                                     const ValueEnumerator &, BitstreamWriter &,
 893                                     SmallVectorImpl<uint64_t> &, unsigned) {
 894   llvm_unreachable("write not implemented");
 895 }
 896 static void WriteMDNamespace(const MDNamespace *, const ValueEnumerator &,
 897                              BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 898                              unsigned) {
 899   llvm_unreachable("write not implemented");
 900 }
 901 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *,
 902                                          const ValueEnumerator &,
 903                                          BitstreamWriter &,
 904                                          SmallVectorImpl<uint64_t> &,
 905                                          unsigned) {
 906   llvm_unreachable("write not implemented");
 907 }
 908 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *,
 909                                           const ValueEnumerator &,
 910                                           BitstreamWriter &,
 911                                           SmallVectorImpl<uint64_t> &,
 912                                           unsigned) {
 913   llvm_unreachable("write not implemented");
 914 }
 915 static void WriteMDGlobalVariable(const MDGlobalVariable *,
 916                                   const ValueEnumerator &, BitstreamWriter &,
 917                                   SmallVectorImpl<uint64_t> &, unsigned) {
 918   llvm_unreachable("write not implemented");
 919 }
 920 static void WriteMDLocalVariable(const MDLocalVariable *,
 921                                  const ValueEnumerator &, BitstreamWriter &,
 922                                  SmallVectorImpl<uint64_t> &, unsigned) {
 923   llvm_unreachable("write not implemented");
 924 }
 925 static void WriteMDExpression(const MDExpression *, const ValueEnumerator &,
 926                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 927                               unsigned) {
 928   llvm_unreachable("write not implemented");
 929 }
 930 static void WriteMDObjCProperty(const MDObjCProperty *, const ValueEnumerator &,
 931                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 932                                 unsigned) {
 933   llvm_unreachable("write not implemented");
 934 }
 935 static void WriteMDImportedEntity(const MDImportedEntity *,
 936                                   const ValueEnumerator &, BitstreamWriter &,
 937                                   SmallVectorImpl<uint64_t> &, unsigned) {
 938   llvm_unreachable("write not implemented");
 939 }
 940
 941 static void WriteModuleMetadata(const Module *M,
 942                                 const ValueEnumerator &VE,
 943                                 BitstreamWriter &Stream) {
 944   const auto &MDs = VE.getMDs();
 945   if (MDs.empty() && M->named_metadata_empty())
 946     return;
 947
 948   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 949
 950   unsigned MDSAbbrev = 0;
 951   if (VE.hasMDString()) {
 952     // Abbrev for METADATA_STRING.
 953     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 954     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 955     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 956     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 957     MDSAbbrev = Stream.EmitAbbrev(Abbv);
 958   }
 959
 960   // Initialize MDNode abbreviations.
 961 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
 962 #include "llvm/IR/Metadata.def"
 963
 964   if (VE.hasMDLocation()) {
 965     // Abbrev for METADATA_LOCATION.
 966     //
 967     // Assume the column is usually under 128, and always output the inlined-at
 968     // location (it's never more expensive than building an array size 1).
 969     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 970     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
 971     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 972     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 973     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 974     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 975     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 976     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
 977   }
 978
 979   if (VE.hasGenericDebugNode()) {
 980     // Abbrev for METADATA_GENERIC_DEBUG.
 981     //
 982     // Assume the column is usually under 128, and always output the inlined-at
 983     // location (it's never more expensive than building an array size 1).
 984     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 985     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
 986     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 987     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 988     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 989     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 990     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 991     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 992     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
 993   }
 994
 995   unsigned NameAbbrev = 0;
 996   if (!M->named_metadata_empty()) {
 997     // Abbrev for METADATA_NAME.
 998     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 999     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1000     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1001     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1002     NameAbbrev = Stream.EmitAbbrev(Abbv);
1003   }
1004
1005   SmallVector<uint64_t, 64> Record;
1006   for (const Metadata *MD : MDs) {
1007     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1008       switch (N->getMetadataID()) {
1009       default:
1010         llvm_unreachable("Invalid MDNode subclass");
1011 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1012   case Metadata::CLASS##Kind:                                                  \
1013     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1014     continue;
1015 #include "llvm/IR/Metadata.def"
1016       }
1017     }
1018     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1019       WriteValueAsMetadata(MDC, VE, Stream, Record);
1020       continue;
1021     }
1022     const MDString *MDS = cast<MDString>(MD);
1023     // Code: [strchar x N]
1024     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1025
1026     // Emit the finished record.
1027     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1028     Record.clear();
1029   }
1030
1031   // Write named metadata.
1032   for (const NamedMDNode &NMD : M->named_metadata()) {
1033     // Write name.
1034     StringRef Str = NMD.getName();
1035     Record.append(Str.bytes_begin(), Str.bytes_end());
1036     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1037     Record.clear();
1038
1039     // Write named metadata operands.
1040     for (const MDNode *N : NMD.operands())
1041       Record.push_back(VE.getMetadataID(N));
1042     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1043     Record.clear();
1044   }
1045
1046   Stream.ExitBlock();
1047 }
1048
1049 static void WriteFunctionLocalMetadata(const Function &F,
1050                                        const ValueEnumerator &VE,
1051                                        BitstreamWriter &Stream) {
1052   bool StartedMetadataBlock = false;
1053   SmallVector<uint64_t, 64> Record;
1054   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1055       VE.getFunctionLocalMDs();
1056   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1057     assert(MDs[i] && "Expected valid function-local metadata");
1058     if (!StartedMetadataBlock) {
1059       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1060       StartedMetadataBlock = true;
1061     }
1062     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1063   }
1064
1065   if (StartedMetadataBlock)
1066     Stream.ExitBlock();
1067 }
1068
1069 static void WriteMetadataAttachment(const Function &F,
1070                                     const ValueEnumerator &VE,
1071                                     BitstreamWriter &Stream) {
1072   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1073
1074   SmallVector<uint64_t, 64> Record;
1075
1076   // Write metadata attachments
1077   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1078   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1079
1080   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1081     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1082          I != E; ++I) {
1083       MDs.clear();
1084       I->getAllMetadataOtherThanDebugLoc(MDs);
1085
1086       // If no metadata, ignore instruction.
1087       if (MDs.empty()) continue;
1088
1089       Record.push_back(VE.getInstructionID(I));
1090
1091       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1092         Record.push_back(MDs[i].first);
1093         Record.push_back(VE.getMetadataID(MDs[i].second));
1094       }
1095       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1096       Record.clear();
1097     }
1098
1099   Stream.ExitBlock();
1100 }
1101
1102 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1103   SmallVector<uint64_t, 64> Record;
1104
1105   // Write metadata kinds
1106   // METADATA_KIND - [n x [id, name]]
1107   SmallVector<StringRef, 8> Names;
1108   M->getMDKindNames(Names);
1109
1110   if (Names.empty()) return;
1111
1112   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1113
1114   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1115     Record.push_back(MDKindID);
1116     StringRef KName = Names[MDKindID];
1117     Record.append(KName.begin(), KName.end());
1118
1119     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1120     Record.clear();
1121   }
1122
1123   Stream.ExitBlock();
1124 }
1125
1126 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1127   if ((int64_t)V >= 0)
1128     Vals.push_back(V << 1);
1129   else
1130     Vals.push_back((-V << 1) | 1);
1131 }
1132
1133 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1134                            const ValueEnumerator &VE,
1135                            BitstreamWriter &Stream, bool isGlobal) {
1136   if (FirstVal == LastVal) return;
1137
1138   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1139
1140   unsigned AggregateAbbrev = 0;
1141   unsigned String8Abbrev = 0;
1142   unsigned CString7Abbrev = 0;
1143   unsigned CString6Abbrev = 0;
1144   // If this is a constant pool for the module, emit module-specific abbrevs.
1145   if (isGlobal) {
1146     // Abbrev for CST_CODE_AGGREGATE.
1147     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1148     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1149     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1151     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1152
1153     // Abbrev for CST_CODE_STRING.
1154     Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1158     String8Abbrev = Stream.EmitAbbrev(Abbv);
1159     // Abbrev for CST_CODE_CSTRING.
1160     Abbv = new BitCodeAbbrev();
1161     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1162     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1164     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1165     // Abbrev for CST_CODE_CSTRING.
1166     Abbv = new BitCodeAbbrev();
1167     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1170     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1171   }
1172
1173   SmallVector<uint64_t, 64> Record;
1174
1175   const ValueEnumerator::ValueList &Vals = VE.getValues();
1176   Type *LastTy = nullptr;
1177   for (unsigned i = FirstVal; i != LastVal; ++i) {
1178     const Value *V = Vals[i].first;
1179     // If we need to switch types, do so now.
1180     if (V->getType() != LastTy) {
1181       LastTy = V->getType();
1182       Record.push_back(VE.getTypeID(LastTy));
1183       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1184                         CONSTANTS_SETTYPE_ABBREV);
1185       Record.clear();
1186     }
1187
1188     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1189       Record.push_back(unsigned(IA->hasSideEffects()) |
1190                        unsigned(IA->isAlignStack()) << 1 |
1191                        unsigned(IA->getDialect()&1) << 2);
1192
1193       // Add the asm string.
1194       const std::string &AsmStr = IA->getAsmString();
1195       Record.push_back(AsmStr.size());
1196       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1197         Record.push_back(AsmStr[i]);
1198
1199       // Add the constraint string.
1200       const std::string &ConstraintStr = IA->getConstraintString();
1201       Record.push_back(ConstraintStr.size());
1202       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1203         Record.push_back(ConstraintStr[i]);
1204       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1205       Record.clear();
1206       continue;
1207     }
1208     const Constant *C = cast<Constant>(V);
1209     unsigned Code = -1U;
1210     unsigned AbbrevToUse = 0;
1211     if (C->isNullValue()) {
1212       Code = bitc::CST_CODE_NULL;
1213     } else if (isa<UndefValue>(C)) {
1214       Code = bitc::CST_CODE_UNDEF;
1215     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1216       if (IV->getBitWidth() <= 64) {
1217         uint64_t V = IV->getSExtValue();
1218         emitSignedInt64(Record, V);
1219         Code = bitc::CST_CODE_INTEGER;
1220         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1221       } else {                             // Wide integers, > 64 bits in size.
1222         // We have an arbitrary precision integer value to write whose
1223         // bit width is > 64. However, in canonical unsigned integer
1224         // format it is likely that the high bits are going to be zero.
1225         // So, we only write the number of active words.
1226         unsigned NWords = IV->getValue().getActiveWords();
1227         const uint64_t *RawWords = IV->getValue().getRawData();
1228         for (unsigned i = 0; i != NWords; ++i) {
1229           emitSignedInt64(Record, RawWords[i]);
1230         }
1231         Code = bitc::CST_CODE_WIDE_INTEGER;
1232       }
1233     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1234       Code = bitc::CST_CODE_FLOAT;
1235       Type *Ty = CFP->getType();
1236       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1237         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1238       } else if (Ty->isX86_FP80Ty()) {
1239         // api needed to prevent premature destruction
1240         // bits are not in the same order as a normal i80 APInt, compensate.
1241         APInt api = CFP->getValueAPF().bitcastToAPInt();
1242         const uint64_t *p = api.getRawData();
1243         Record.push_back((p[1] << 48) | (p[0] >> 16));
1244         Record.push_back(p[0] & 0xffffLL);
1245       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1246         APInt api = CFP->getValueAPF().bitcastToAPInt();
1247         const uint64_t *p = api.getRawData();
1248         Record.push_back(p[0]);
1249         Record.push_back(p[1]);
1250       } else {
1251         assert (0 && "Unknown FP type!");
1252       }
1253     } else if (isa<ConstantDataSequential>(C) &&
1254                cast<ConstantDataSequential>(C)->isString()) {
1255       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1256       // Emit constant strings specially.
1257       unsigned NumElts = Str->getNumElements();
1258       // If this is a null-terminated string, use the denser CSTRING encoding.
1259       if (Str->isCString()) {
1260         Code = bitc::CST_CODE_CSTRING;
1261         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1262       } else {
1263         Code = bitc::CST_CODE_STRING;
1264         AbbrevToUse = String8Abbrev;
1265       }
1266       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1267       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1268       for (unsigned i = 0; i != NumElts; ++i) {
1269         unsigned char V = Str->getElementAsInteger(i);
1270         Record.push_back(V);
1271         isCStr7 &= (V & 128) == 0;
1272         if (isCStrChar6)
1273           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1274       }
1275
1276       if (isCStrChar6)
1277         AbbrevToUse = CString6Abbrev;
1278       else if (isCStr7)
1279         AbbrevToUse = CString7Abbrev;
1280     } else if (const ConstantDataSequential *CDS =
1281                   dyn_cast<ConstantDataSequential>(C)) {
1282       Code = bitc::CST_CODE_DATA;
1283       Type *EltTy = CDS->getType()->getElementType();
1284       if (isa<IntegerType>(EltTy)) {
1285         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1286           Record.push_back(CDS->getElementAsInteger(i));
1287       } else if (EltTy->isFloatTy()) {
1288         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1289           union { float F; uint32_t I; };
1290           F = CDS->getElementAsFloat(i);
1291           Record.push_back(I);
1292         }
1293       } else {
1294         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1295         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1296           union { double F; uint64_t I; };
1297           F = CDS->getElementAsDouble(i);
1298           Record.push_back(I);
1299         }
1300       }
1301     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1302                isa<ConstantVector>(C)) {
1303       Code = bitc::CST_CODE_AGGREGATE;
1304       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1305         Record.push_back(VE.getValueID(C->getOperand(i)));
1306       AbbrevToUse = AggregateAbbrev;
1307     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1308       switch (CE->getOpcode()) {
1309       default:
1310         if (Instruction::isCast(CE->getOpcode())) {
1311           Code = bitc::CST_CODE_CE_CAST;
1312           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1313           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1314           Record.push_back(VE.getValueID(C->getOperand(0)));
1315           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1316         } else {
1317           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1318           Code = bitc::CST_CODE_CE_BINOP;
1319           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1320           Record.push_back(VE.getValueID(C->getOperand(0)));
1321           Record.push_back(VE.getValueID(C->getOperand(1)));
1322           uint64_t Flags = GetOptimizationFlags(CE);
1323           if (Flags != 0)
1324             Record.push_back(Flags);
1325         }
1326         break;
1327       case Instruction::GetElementPtr:
1328         Code = bitc::CST_CODE_CE_GEP;
1329         if (cast<GEPOperator>(C)->isInBounds())
1330           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1331         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1332           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1333           Record.push_back(VE.getValueID(C->getOperand(i)));
1334         }
1335         break;
1336       case Instruction::Select:
1337         Code = bitc::CST_CODE_CE_SELECT;
1338         Record.push_back(VE.getValueID(C->getOperand(0)));
1339         Record.push_back(VE.getValueID(C->getOperand(1)));
1340         Record.push_back(VE.getValueID(C->getOperand(2)));
1341         break;
1342       case Instruction::ExtractElement:
1343         Code = bitc::CST_CODE_CE_EXTRACTELT;
1344         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1345         Record.push_back(VE.getValueID(C->getOperand(0)));
1346         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1347         Record.push_back(VE.getValueID(C->getOperand(1)));
1348         break;
1349       case Instruction::InsertElement:
1350         Code = bitc::CST_CODE_CE_INSERTELT;
1351         Record.push_back(VE.getValueID(C->getOperand(0)));
1352         Record.push_back(VE.getValueID(C->getOperand(1)));
1353         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1354         Record.push_back(VE.getValueID(C->getOperand(2)));
1355         break;
1356       case Instruction::ShuffleVector:
1357         // If the return type and argument types are the same, this is a
1358         // standard shufflevector instruction.  If the types are different,
1359         // then the shuffle is widening or truncating the input vectors, and
1360         // the argument type must also be encoded.
1361         if (C->getType() == C->getOperand(0)->getType()) {
1362           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1363         } else {
1364           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1365           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1366         }
1367         Record.push_back(VE.getValueID(C->getOperand(0)));
1368         Record.push_back(VE.getValueID(C->getOperand(1)));
1369         Record.push_back(VE.getValueID(C->getOperand(2)));
1370         break;
1371       case Instruction::ICmp:
1372       case Instruction::FCmp:
1373         Code = bitc::CST_CODE_CE_CMP;
1374         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1375         Record.push_back(VE.getValueID(C->getOperand(0)));
1376         Record.push_back(VE.getValueID(C->getOperand(1)));
1377         Record.push_back(CE->getPredicate());
1378         break;
1379       }
1380     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1381       Code = bitc::CST_CODE_BLOCKADDRESS;
1382       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1383       Record.push_back(VE.getValueID(BA->getFunction()));
1384       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1385     } else {
1386 #ifndef NDEBUG
1387       C->dump();
1388 #endif
1389       llvm_unreachable("Unknown constant!");
1390     }
1391     Stream.EmitRecord(Code, Record, AbbrevToUse);
1392     Record.clear();
1393   }
1394
1395   Stream.ExitBlock();
1396 }
1397
1398 static void WriteModuleConstants(const ValueEnumerator &VE,
1399                                  BitstreamWriter &Stream) {
1400   const ValueEnumerator::ValueList &Vals = VE.getValues();
1401
1402   // Find the first constant to emit, which is the first non-globalvalue value.
1403   // We know globalvalues have been emitted by WriteModuleInfo.
1404   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1405     if (!isa<GlobalValue>(Vals[i].first)) {
1406       WriteConstants(i, Vals.size(), VE, Stream, true);
1407       return;
1408     }
1409   }
1410 }
1411
1412 /// PushValueAndType - The file has to encode both the value and type id for
1413 /// many values, because we need to know what type to create for forward
1414 /// references.  However, most operands are not forward references, so this type
1415 /// field is not needed.
1416 ///
1417 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1418 /// instruction ID, then it is a forward reference, and it also includes the
1419 /// type ID.  The value ID that is written is encoded relative to the InstID.
1420 static bool PushValueAndType(const Value *V, unsigned InstID,
1421                              SmallVectorImpl<unsigned> &Vals,
1422                              ValueEnumerator &VE) {
1423   unsigned ValID = VE.getValueID(V);
1424   // Make encoding relative to the InstID.
1425   Vals.push_back(InstID - ValID);
1426   if (ValID >= InstID) {
1427     Vals.push_back(VE.getTypeID(V->getType()));
1428     return true;
1429   }
1430   return false;
1431 }
1432
1433 /// pushValue - Like PushValueAndType, but where the type of the value is
1434 /// omitted (perhaps it was already encoded in an earlier operand).
1435 static void pushValue(const Value *V, unsigned InstID,
1436                       SmallVectorImpl<unsigned> &Vals,
1437                       ValueEnumerator &VE) {
1438   unsigned ValID = VE.getValueID(V);
1439   Vals.push_back(InstID - ValID);
1440 }
1441
1442 static void pushValueSigned(const Value *V, unsigned InstID,
1443                             SmallVectorImpl<uint64_t> &Vals,
1444                             ValueEnumerator &VE) {
1445   unsigned ValID = VE.getValueID(V);
1446   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1447   emitSignedInt64(Vals, diff);
1448 }
1449
1450 /// WriteInstruction - Emit an instruction to the specified stream.
1451 static void WriteInstruction(const Instruction &I, unsigned InstID,
1452                              ValueEnumerator &VE, BitstreamWriter &Stream,
1453                              SmallVectorImpl<unsigned> &Vals) {
1454   unsigned Code = 0;
1455   unsigned AbbrevToUse = 0;
1456   VE.setInstructionID(&I);
1457   switch (I.getOpcode()) {
1458   default:
1459     if (Instruction::isCast(I.getOpcode())) {
1460       Code = bitc::FUNC_CODE_INST_CAST;
1461       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1462         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1463       Vals.push_back(VE.getTypeID(I.getType()));
1464       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1465     } else {
1466       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1467       Code = bitc::FUNC_CODE_INST_BINOP;
1468       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1469         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1470       pushValue(I.getOperand(1), InstID, Vals, VE);
1471       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1472       uint64_t Flags = GetOptimizationFlags(&I);
1473       if (Flags != 0) {
1474         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1475           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1476         Vals.push_back(Flags);
1477       }
1478     }
1479     break;
1480
1481   case Instruction::GetElementPtr:
1482     Code = bitc::FUNC_CODE_INST_GEP;
1483     if (cast<GEPOperator>(&I)->isInBounds())
1484       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1485     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1486       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1487     break;
1488   case Instruction::ExtractValue: {
1489     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1490     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1491     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1492     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1493       Vals.push_back(*i);
1494     break;
1495   }
1496   case Instruction::InsertValue: {
1497     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1498     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1499     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1500     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1501     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1502       Vals.push_back(*i);
1503     break;
1504   }
1505   case Instruction::Select:
1506     Code = bitc::FUNC_CODE_INST_VSELECT;
1507     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1508     pushValue(I.getOperand(2), InstID, Vals, VE);
1509     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1510     break;
1511   case Instruction::ExtractElement:
1512     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1513     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1514     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1515     break;
1516   case Instruction::InsertElement:
1517     Code = bitc::FUNC_CODE_INST_INSERTELT;
1518     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1519     pushValue(I.getOperand(1), InstID, Vals, VE);
1520     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1521     break;
1522   case Instruction::ShuffleVector:
1523     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1524     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1525     pushValue(I.getOperand(1), InstID, Vals, VE);
1526     pushValue(I.getOperand(2), InstID, Vals, VE);
1527     break;
1528   case Instruction::ICmp:
1529   case Instruction::FCmp:
1530     // compare returning Int1Ty or vector of Int1Ty
1531     Code = bitc::FUNC_CODE_INST_CMP2;
1532     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1533     pushValue(I.getOperand(1), InstID, Vals, VE);
1534     Vals.push_back(cast<CmpInst>(I).getPredicate());
1535     break;
1536
1537   case Instruction::Ret:
1538     {
1539       Code = bitc::FUNC_CODE_INST_RET;
1540       unsigned NumOperands = I.getNumOperands();
1541       if (NumOperands == 0)
1542         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1543       else if (NumOperands == 1) {
1544         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1545           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1546       } else {
1547         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1548           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1549       }
1550     }
1551     break;
1552   case Instruction::Br:
1553     {
1554       Code = bitc::FUNC_CODE_INST_BR;
1555       const BranchInst &II = cast<BranchInst>(I);
1556       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1557       if (II.isConditional()) {
1558         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1559         pushValue(II.getCondition(), InstID, Vals, VE);
1560       }
1561     }
1562     break;
1563   case Instruction::Switch:
1564     {
1565       Code = bitc::FUNC_CODE_INST_SWITCH;
1566       const SwitchInst &SI = cast<SwitchInst>(I);
1567       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1568       pushValue(SI.getCondition(), InstID, Vals, VE);
1569       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1570       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1571            i != e; ++i) {
1572         Vals.push_back(VE.getValueID(i.getCaseValue()));
1573         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1574       }
1575     }
1576     break;
1577   case Instruction::IndirectBr:
1578     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1579     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1580     // Encode the address operand as relative, but not the basic blocks.
1581     pushValue(I.getOperand(0), InstID, Vals, VE);
1582     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1583       Vals.push_back(VE.getValueID(I.getOperand(i)));
1584     break;
1585
1586   case Instruction::Invoke: {
1587     const InvokeInst *II = cast<InvokeInst>(&I);
1588     const Value *Callee(II->getCalledValue());
1589     PointerType *PTy = cast<PointerType>(Callee->getType());
1590     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1591     Code = bitc::FUNC_CODE_INST_INVOKE;
1592
1593     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1594     Vals.push_back(II->getCallingConv());
1595     Vals.push_back(VE.getValueID(II->getNormalDest()));
1596     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1597     PushValueAndType(Callee, InstID, Vals, VE);
1598
1599     // Emit value #'s for the fixed parameters.
1600     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1601       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1602
1603     // Emit type/value pairs for varargs params.
1604     if (FTy->isVarArg()) {
1605       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1606            i != e; ++i)
1607         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1608     }
1609     break;
1610   }
1611   case Instruction::Resume:
1612     Code = bitc::FUNC_CODE_INST_RESUME;
1613     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1614     break;
1615   case Instruction::Unreachable:
1616     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1617     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1618     break;
1619
1620   case Instruction::PHI: {
1621     const PHINode &PN = cast<PHINode>(I);
1622     Code = bitc::FUNC_CODE_INST_PHI;
1623     // With the newer instruction encoding, forward references could give
1624     // negative valued IDs.  This is most common for PHIs, so we use
1625     // signed VBRs.
1626     SmallVector<uint64_t, 128> Vals64;
1627     Vals64.push_back(VE.getTypeID(PN.getType()));
1628     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1629       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1630       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1631     }
1632     // Emit a Vals64 vector and exit.
1633     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1634     Vals64.clear();
1635     return;
1636   }
1637
1638   case Instruction::LandingPad: {
1639     const LandingPadInst &LP = cast<LandingPadInst>(I);
1640     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1641     Vals.push_back(VE.getTypeID(LP.getType()));
1642     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1643     Vals.push_back(LP.isCleanup());
1644     Vals.push_back(LP.getNumClauses());
1645     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1646       if (LP.isCatch(I))
1647         Vals.push_back(LandingPadInst::Catch);
1648       else
1649         Vals.push_back(LandingPadInst::Filter);
1650       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1651     }
1652     break;
1653   }
1654
1655   case Instruction::Alloca: {
1656     Code = bitc::FUNC_CODE_INST_ALLOCA;
1657     Vals.push_back(VE.getTypeID(I.getType()));
1658     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1659     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1660     const AllocaInst &AI = cast<AllocaInst>(I);
1661     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1662     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1663            "not enough bits for maximum alignment");
1664     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1665     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1666     Vals.push_back(AlignRecord);
1667     break;
1668   }
1669
1670   case Instruction::Load:
1671     if (cast<LoadInst>(I).isAtomic()) {
1672       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1673       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1674     } else {
1675       Code = bitc::FUNC_CODE_INST_LOAD;
1676       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1677         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1678     }
1679     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1680     Vals.push_back(cast<LoadInst>(I).isVolatile());
1681     if (cast<LoadInst>(I).isAtomic()) {
1682       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1683       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1684     }
1685     break;
1686   case Instruction::Store:
1687     if (cast<StoreInst>(I).isAtomic())
1688       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1689     else
1690       Code = bitc::FUNC_CODE_INST_STORE;
1691     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1692     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1693     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1694     Vals.push_back(cast<StoreInst>(I).isVolatile());
1695     if (cast<StoreInst>(I).isAtomic()) {
1696       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1697       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1698     }
1699     break;
1700   case Instruction::AtomicCmpXchg:
1701     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1702     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1703     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1704     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1705     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1706     Vals.push_back(GetEncodedOrdering(
1707                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1708     Vals.push_back(GetEncodedSynchScope(
1709                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1710     Vals.push_back(GetEncodedOrdering(
1711                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1712     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1713     break;
1714   case Instruction::AtomicRMW:
1715     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1716     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1717     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1718     Vals.push_back(GetEncodedRMWOperation(
1719                      cast<AtomicRMWInst>(I).getOperation()));
1720     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1721     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1722     Vals.push_back(GetEncodedSynchScope(
1723                      cast<AtomicRMWInst>(I).getSynchScope()));
1724     break;
1725   case Instruction::Fence:
1726     Code = bitc::FUNC_CODE_INST_FENCE;
1727     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1728     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1729     break;
1730   case Instruction::Call: {
1731     const CallInst &CI = cast<CallInst>(I);
1732     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1733     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1734
1735     Code = bitc::FUNC_CODE_INST_CALL;
1736
1737     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1738     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1739                    unsigned(CI.isMustTailCall()) << 14);
1740     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1741
1742     // Emit value #'s for the fixed parameters.
1743     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1744       // Check for labels (can happen with asm labels).
1745       if (FTy->getParamType(i)->isLabelTy())
1746         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1747       else
1748         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1749     }
1750
1751     // Emit type/value pairs for varargs params.
1752     if (FTy->isVarArg()) {
1753       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1754            i != e; ++i)
1755         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1756     }
1757     break;
1758   }
1759   case Instruction::VAArg:
1760     Code = bitc::FUNC_CODE_INST_VAARG;
1761     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1762     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1763     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1764     break;
1765   }
1766
1767   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1768   Vals.clear();
1769 }
1770
1771 // Emit names for globals/functions etc.
1772 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1773                                   const ValueEnumerator &VE,
1774                                   BitstreamWriter &Stream) {
1775   if (VST.empty()) return;
1776   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1777
1778   // FIXME: Set up the abbrev, we know how many values there are!
1779   // FIXME: We know if the type names can use 7-bit ascii.
1780   SmallVector<unsigned, 64> NameVals;
1781
1782   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1783        SI != SE; ++SI) {
1784
1785     const ValueName &Name = *SI;
1786
1787     // Figure out the encoding to use for the name.
1788     bool is7Bit = true;
1789     bool isChar6 = true;
1790     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1791          C != E; ++C) {
1792       if (isChar6)
1793         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1794       if ((unsigned char)*C & 128) {
1795         is7Bit = false;
1796         break;  // don't bother scanning the rest.
1797       }
1798     }
1799
1800     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1801
1802     // VST_ENTRY:   [valueid, namechar x N]
1803     // VST_BBENTRY: [bbid, namechar x N]
1804     unsigned Code;
1805     if (isa<BasicBlock>(SI->getValue())) {
1806       Code = bitc::VST_CODE_BBENTRY;
1807       if (isChar6)
1808         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1809     } else {
1810       Code = bitc::VST_CODE_ENTRY;
1811       if (isChar6)
1812         AbbrevToUse = VST_ENTRY_6_ABBREV;
1813       else if (is7Bit)
1814         AbbrevToUse = VST_ENTRY_7_ABBREV;
1815     }
1816
1817     NameVals.push_back(VE.getValueID(SI->getValue()));
1818     for (const char *P = Name.getKeyData(),
1819          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1820       NameVals.push_back((unsigned char)*P);
1821
1822     // Emit the finished record.
1823     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1824     NameVals.clear();
1825   }
1826   Stream.ExitBlock();
1827 }
1828
1829 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1830                          BitstreamWriter &Stream) {
1831   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1832   unsigned Code;
1833   if (isa<BasicBlock>(Order.V))
1834     Code = bitc::USELIST_CODE_BB;
1835   else
1836     Code = bitc::USELIST_CODE_DEFAULT;
1837
1838   SmallVector<uint64_t, 64> Record;
1839   for (unsigned I : Order.Shuffle)
1840     Record.push_back(I);
1841   Record.push_back(VE.getValueID(Order.V));
1842   Stream.EmitRecord(Code, Record);
1843 }
1844
1845 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1846                               BitstreamWriter &Stream) {
1847   auto hasMore = [&]() {
1848     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1849   };
1850   if (!hasMore())
1851     // Nothing to do.
1852     return;
1853
1854   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1855   while (hasMore()) {
1856     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1857     VE.UseListOrders.pop_back();
1858   }
1859   Stream.ExitBlock();
1860 }
1861
1862 /// WriteFunction - Emit a function body to the module stream.
1863 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1864                           BitstreamWriter &Stream) {
1865   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1866   VE.incorporateFunction(F);
1867
1868   SmallVector<unsigned, 64> Vals;
1869
1870   // Emit the number of basic blocks, so the reader can create them ahead of
1871   // time.
1872   Vals.push_back(VE.getBasicBlocks().size());
1873   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1874   Vals.clear();
1875
1876   // If there are function-local constants, emit them now.
1877   unsigned CstStart, CstEnd;
1878   VE.getFunctionConstantRange(CstStart, CstEnd);
1879   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1880
1881   // If there is function-local metadata, emit it now.
1882   WriteFunctionLocalMetadata(F, VE, Stream);
1883
1884   // Keep a running idea of what the instruction ID is.
1885   unsigned InstID = CstEnd;
1886
1887   bool NeedsMetadataAttachment = false;
1888
1889   DebugLoc LastDL;
1890
1891   // Finally, emit all the instructions, in order.
1892   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1893     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1894          I != E; ++I) {
1895       WriteInstruction(*I, InstID, VE, Stream, Vals);
1896
1897       if (!I->getType()->isVoidTy())
1898         ++InstID;
1899
1900       // If the instruction has metadata, write a metadata attachment later.
1901       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1902
1903       // If the instruction has a debug location, emit it.
1904       DebugLoc DL = I->getDebugLoc();
1905       if (DL.isUnknown()) {
1906         // nothing todo.
1907       } else if (DL == LastDL) {
1908         // Just repeat the same debug loc as last time.
1909         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1910       } else {
1911         MDNode *Scope, *IA;
1912         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1913         assert(Scope && "Expected valid scope");
1914
1915         Vals.push_back(DL.getLine());
1916         Vals.push_back(DL.getCol());
1917         Vals.push_back(VE.getMetadataOrNullID(Scope));
1918         Vals.push_back(VE.getMetadataOrNullID(IA));
1919         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1920         Vals.clear();
1921
1922         LastDL = DL;
1923       }
1924     }
1925
1926   // Emit names for all the instructions etc.
1927   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1928
1929   if (NeedsMetadataAttachment)
1930     WriteMetadataAttachment(F, VE, Stream);
1931   if (shouldPreserveBitcodeUseListOrder())
1932     WriteUseListBlock(&F, VE, Stream);
1933   VE.purgeFunction();
1934   Stream.ExitBlock();
1935 }
1936
1937 // Emit blockinfo, which defines the standard abbreviations etc.
1938 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1939   // We only want to emit block info records for blocks that have multiple
1940   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1941   // Other blocks can define their abbrevs inline.
1942   Stream.EnterBlockInfoBlock(2);
1943
1944   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1945     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1946     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1947     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1948     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1949     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1950     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1951                                    Abbv) != VST_ENTRY_8_ABBREV)
1952       llvm_unreachable("Unexpected abbrev ordering!");
1953   }
1954
1955   { // 7-bit fixed width VST_ENTRY strings.
1956     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1957     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1958     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1959     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1960     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1961     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1962                                    Abbv) != VST_ENTRY_7_ABBREV)
1963       llvm_unreachable("Unexpected abbrev ordering!");
1964   }
1965   { // 6-bit char6 VST_ENTRY strings.
1966     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1967     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1968     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1969     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1970     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1971     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1972                                    Abbv) != VST_ENTRY_6_ABBREV)
1973       llvm_unreachable("Unexpected abbrev ordering!");
1974   }
1975   { // 6-bit char6 VST_BBENTRY strings.
1976     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1977     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1978     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1979     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1980     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1981     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1982                                    Abbv) != VST_BBENTRY_6_ABBREV)
1983       llvm_unreachable("Unexpected abbrev ordering!");
1984   }
1985
1986
1987
1988   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1989     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1990     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1991     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1992                               Log2_32_Ceil(VE.getTypes().size()+1)));
1993     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1994                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1995       llvm_unreachable("Unexpected abbrev ordering!");
1996   }
1997
1998   { // INTEGER abbrev for CONSTANTS_BLOCK.
1999     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2000     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
2001     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
2002     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2003                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
2004       llvm_unreachable("Unexpected abbrev ordering!");
2005   }
2006
2007   { // CE_CAST abbrev for CONSTANTS_BLOCK.
2008     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2009     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2010     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2011     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2012                               Log2_32_Ceil(VE.getTypes().size()+1)));
2013     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2014
2015     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2016                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2017       llvm_unreachable("Unexpected abbrev ordering!");
2018   }
2019   { // NULL abbrev for CONSTANTS_BLOCK.
2020     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2021     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2022     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2023                                    Abbv) != CONSTANTS_NULL_Abbrev)
2024       llvm_unreachable("Unexpected abbrev ordering!");
2025   }
2026
2027   // FIXME: This should only use space for first class types!
2028
2029   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2030     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2031     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2032     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2033     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2034     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2035     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2036                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2037       llvm_unreachable("Unexpected abbrev ordering!");
2038   }
2039   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2040     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2041     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2042     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2043     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2044     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2045     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2046                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2047       llvm_unreachable("Unexpected abbrev ordering!");
2048   }
2049   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
2050     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2051     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2052     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2053     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2054     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2055     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2056     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2057                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2058       llvm_unreachable("Unexpected abbrev ordering!");
2059   }
2060   { // INST_CAST abbrev for FUNCTION_BLOCK.
2061     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2062     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2063     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2064     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2065                               Log2_32_Ceil(VE.getTypes().size()+1)));
2066     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2067     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2068                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2069       llvm_unreachable("Unexpected abbrev ordering!");
2070   }
2071
2072   { // INST_RET abbrev for FUNCTION_BLOCK.
2073     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2074     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2075     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2076                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2077       llvm_unreachable("Unexpected abbrev ordering!");
2078   }
2079   { // INST_RET abbrev for FUNCTION_BLOCK.
2080     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2081     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2082     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2083     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2084                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2085       llvm_unreachable("Unexpected abbrev ordering!");
2086   }
2087   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2088     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2089     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2090     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2091                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2092       llvm_unreachable("Unexpected abbrev ordering!");
2093   }
2094
2095   Stream.ExitBlock();
2096 }
2097
2098 /// WriteModule - Emit the specified module to the bitstream.
2099 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2100   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2101
2102   SmallVector<unsigned, 1> Vals;
2103   unsigned CurVersion = 1;
2104   Vals.push_back(CurVersion);
2105   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2106
2107   // Analyze the module, enumerating globals, functions, etc.
2108   ValueEnumerator VE(*M);
2109
2110   // Emit blockinfo, which defines the standard abbreviations etc.
2111   WriteBlockInfo(VE, Stream);
2112
2113   // Emit information about attribute groups.
2114   WriteAttributeGroupTable(VE, Stream);
2115
2116   // Emit information about parameter attributes.
2117   WriteAttributeTable(VE, Stream);
2118
2119   // Emit information describing all of the types in the module.
2120   WriteTypeTable(VE, Stream);
2121
2122   writeComdats(VE, Stream);
2123
2124   // Emit top-level description of module, including target triple, inline asm,
2125   // descriptors for global variables, and function prototype info.
2126   WriteModuleInfo(M, VE, Stream);
2127
2128   // Emit constants.
2129   WriteModuleConstants(VE, Stream);
2130
2131   // Emit metadata.
2132   WriteModuleMetadata(M, VE, Stream);
2133
2134   // Emit metadata.
2135   WriteModuleMetadataStore(M, Stream);
2136
2137   // Emit names for globals/functions etc.
2138   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2139
2140   // Emit module-level use-lists.
2141   if (shouldPreserveBitcodeUseListOrder())
2142     WriteUseListBlock(nullptr, VE, Stream);
2143
2144   // Emit function bodies.
2145   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2146     if (!F->isDeclaration())
2147       WriteFunction(*F, VE, Stream);
2148
2149   Stream.ExitBlock();
2150 }
2151
2152 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2153 /// header and trailer to make it compatible with the system archiver.  To do
2154 /// this we emit the following header, and then emit a trailer that pads the
2155 /// file out to be a multiple of 16 bytes.
2156 ///
2157 /// struct bc_header {
2158 ///   uint32_t Magic;         // 0x0B17C0DE
2159 ///   uint32_t Version;       // Version, currently always 0.
2160 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2161 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2162 ///   uint32_t CPUType;       // CPU specifier.
2163 ///   ... potentially more later ...
2164 /// };
2165 enum {
2166   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2167   DarwinBCHeaderSize = 5*4
2168 };
2169
2170 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2171                                uint32_t &Position) {
2172   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2173   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2174   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2175   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2176   Position += 4;
2177 }
2178
2179 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2180                                          const Triple &TT) {
2181   unsigned CPUType = ~0U;
2182
2183   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2184   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2185   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2186   // specific constants here because they are implicitly part of the Darwin ABI.
2187   enum {
2188     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2189     DARWIN_CPU_TYPE_X86        = 7,
2190     DARWIN_CPU_TYPE_ARM        = 12,
2191     DARWIN_CPU_TYPE_POWERPC    = 18
2192   };
2193
2194   Triple::ArchType Arch = TT.getArch();
2195   if (Arch == Triple::x86_64)
2196     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2197   else if (Arch == Triple::x86)
2198     CPUType = DARWIN_CPU_TYPE_X86;
2199   else if (Arch == Triple::ppc)
2200     CPUType = DARWIN_CPU_TYPE_POWERPC;
2201   else if (Arch == Triple::ppc64)
2202     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2203   else if (Arch == Triple::arm || Arch == Triple::thumb)
2204     CPUType = DARWIN_CPU_TYPE_ARM;
2205
2206   // Traditional Bitcode starts after header.
2207   assert(Buffer.size() >= DarwinBCHeaderSize &&
2208          "Expected header size to be reserved");
2209   unsigned BCOffset = DarwinBCHeaderSize;
2210   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2211
2212   // Write the magic and version.
2213   unsigned Position = 0;
2214   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2215   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2216   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2217   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2218   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2219
2220   // If the file is not a multiple of 16 bytes, insert dummy padding.
2221   while (Buffer.size() & 15)
2222     Buffer.push_back(0);
2223 }
2224
2225 /// WriteBitcodeToFile - Write the specified module to the specified output
2226 /// stream.
2227 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2228   SmallVector<char, 0> Buffer;
2229   Buffer.reserve(256*1024);
2230
2231   // If this is darwin or another generic macho target, reserve space for the
2232   // header.
2233   Triple TT(M->getTargetTriple());
2234   if (TT.isOSDarwin())
2235     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2236
2237   // Emit the module into the buffer.
2238   {
2239     BitstreamWriter Stream(Buffer);
2240
2241     // Emit the file header.
2242     Stream.Emit((unsigned)'B', 8);
2243     Stream.Emit((unsigned)'C', 8);
2244     Stream.Emit(0x0, 4);
2245     Stream.Emit(0xC, 4);
2246     Stream.Emit(0xE, 4);
2247     Stream.Emit(0xD, 4);
2248
2249     // Emit the module.
2250     WriteModule(M, Stream);
2251   }
2252
2253   if (TT.isOSDarwin())
2254     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2255
2256   // Write the generated bitstream to "Out".
2257   Out.write((char*)&Buffer.front(), Buffer.size());
2258 }