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 *, const ValueEnumerator &,
 842                              BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 843                              unsigned) {
 844   llvm_unreachable("write not implemented");
 845 }
 846 static void WriteMDDerivedType(const MDDerivedType *, const ValueEnumerator &,
 847                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 848                                unsigned) {
 849   llvm_unreachable("write not implemented");
 850 }
 851 static void WriteMDCompositeType(const MDCompositeType *,
 852                                  const ValueEnumerator &, BitstreamWriter &,
 853                                  SmallVectorImpl<uint64_t> &, unsigned) {
 854   llvm_unreachable("write not implemented");
 855 }
 856 static void WriteMDSubroutineType(const MDSubroutineType *,
 857                                   const ValueEnumerator &, BitstreamWriter &,
 858                                   SmallVectorImpl<uint64_t> &, unsigned) {
 859   llvm_unreachable("write not implemented");
 860 }
 861 static void WriteMDFile(const MDFile *, const ValueEnumerator &,
 862                         BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 863                         unsigned) {
 864   llvm_unreachable("write not implemented");
 865 }
 866 static void WriteMDCompileUnit(const MDCompileUnit *, const ValueEnumerator &,
 867                                BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 868                                unsigned) {
 869   llvm_unreachable("write not implemented");
 870 }
 871 static void WriteMDSubprogram(const MDSubprogram *, const ValueEnumerator &,
 872                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 873                               unsigned) {
 874   llvm_unreachable("write not implemented");
 875 }
 876 static void WriteMDLexicalBlock(const MDLexicalBlock *, const ValueEnumerator &,
 877                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 878                                 unsigned) {
 879   llvm_unreachable("write not implemented");
 880 }
 881 static void WriteMDLexicalBlockFile(const MDLexicalBlockFile *,
 882                                     const ValueEnumerator &, BitstreamWriter &,
 883                                     SmallVectorImpl<uint64_t> &, unsigned) {
 884   llvm_unreachable("write not implemented");
 885 }
 886 static void WriteMDNamespace(const MDNamespace *, const ValueEnumerator &,
 887                              BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 888                              unsigned) {
 889   llvm_unreachable("write not implemented");
 890 }
 891 static void WriteMDTemplateTypeParameter(const MDTemplateTypeParameter *,
 892                                          const ValueEnumerator &,
 893                                          BitstreamWriter &,
 894                                          SmallVectorImpl<uint64_t> &,
 895                                          unsigned) {
 896   llvm_unreachable("write not implemented");
 897 }
 898 static void WriteMDTemplateValueParameter(const MDTemplateValueParameter *,
 899                                           const ValueEnumerator &,
 900                                           BitstreamWriter &,
 901                                           SmallVectorImpl<uint64_t> &,
 902                                           unsigned) {
 903   llvm_unreachable("write not implemented");
 904 }
 905 static void WriteMDGlobalVariable(const MDGlobalVariable *,
 906                                   const ValueEnumerator &, BitstreamWriter &,
 907                                   SmallVectorImpl<uint64_t> &, unsigned) {
 908   llvm_unreachable("write not implemented");
 909 }
 910 static void WriteMDLocalVariable(const MDLocalVariable *,
 911                                  const ValueEnumerator &, BitstreamWriter &,
 912                                  SmallVectorImpl<uint64_t> &, unsigned) {
 913   llvm_unreachable("write not implemented");
 914 }
 915 static void WriteMDExpression(const MDExpression *, const ValueEnumerator &,
 916                               BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 917                               unsigned) {
 918   llvm_unreachable("write not implemented");
 919 }
 920 static void WriteMDObjCProperty(const MDObjCProperty *, const ValueEnumerator &,
 921                                 BitstreamWriter &, SmallVectorImpl<uint64_t> &,
 922                                 unsigned) {
 923   llvm_unreachable("write not implemented");
 924 }
 925 static void WriteMDImportedEntity(const MDImportedEntity *,
 926                                   const ValueEnumerator &, BitstreamWriter &,
 927                                   SmallVectorImpl<uint64_t> &, unsigned) {
 928   llvm_unreachable("write not implemented");
 929 }
 930
 931 static void WriteModuleMetadata(const Module *M,
 932                                 const ValueEnumerator &VE,
 933                                 BitstreamWriter &Stream) {
 934   const auto &MDs = VE.getMDs();
 935   if (MDs.empty() && M->named_metadata_empty())
 936     return;
 937
 938   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 939
 940   unsigned MDSAbbrev = 0;
 941   if (VE.hasMDString()) {
 942     // Abbrev for METADATA_STRING.
 943     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 944     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 945     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 946     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 947     MDSAbbrev = Stream.EmitAbbrev(Abbv);
 948   }
 949
 950   // Initialize MDNode abbreviations.
 951 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
 952 #include "llvm/IR/Metadata.def"
 953
 954   if (VE.hasMDLocation()) {
 955     // Abbrev for METADATA_LOCATION.
 956     //
 957     // Assume the column is usually under 128, and always output the inlined-at
 958     // location (it's never more expensive than building an array size 1).
 959     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 960     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
 961     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 962     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 963     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 964     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 965     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 966     MDLocationAbbrev = Stream.EmitAbbrev(Abbv);
 967   }
 968
 969   if (VE.hasGenericDebugNode()) {
 970     // Abbrev for METADATA_GENERIC_DEBUG.
 971     //
 972     // Assume the column is usually under 128, and always output the inlined-at
 973     // location (it's never more expensive than building an array size 1).
 974     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 975     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
 976     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 977     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 978     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 979     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 980     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 981     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 982     GenericDebugNodeAbbrev = Stream.EmitAbbrev(Abbv);
 983   }
 984
 985   unsigned NameAbbrev = 0;
 986   if (!M->named_metadata_empty()) {
 987     // Abbrev for METADATA_NAME.
 988     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 989     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
 990     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 991     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 992     NameAbbrev = Stream.EmitAbbrev(Abbv);
 993   }
 994
 995   SmallVector<uint64_t, 64> Record;
 996   for (const Metadata *MD : MDs) {
 997     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
 998       switch (N->getMetadataID()) {
 999       default:
1000         llvm_unreachable("Invalid MDNode subclass");
1001 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1002   case Metadata::CLASS##Kind:                                                  \
1003     Write##CLASS(cast<CLASS>(N), VE, Stream, Record, CLASS##Abbrev);           \
1004     continue;
1005 #include "llvm/IR/Metadata.def"
1006       }
1007     }
1008     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
1009       WriteValueAsMetadata(MDC, VE, Stream, Record);
1010       continue;
1011     }
1012     const MDString *MDS = cast<MDString>(MD);
1013     // Code: [strchar x N]
1014     Record.append(MDS->bytes_begin(), MDS->bytes_end());
1015
1016     // Emit the finished record.
1017     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
1018     Record.clear();
1019   }
1020
1021   // Write named metadata.
1022   for (const NamedMDNode &NMD : M->named_metadata()) {
1023     // Write name.
1024     StringRef Str = NMD.getName();
1025     Record.append(Str.bytes_begin(), Str.bytes_end());
1026     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
1027     Record.clear();
1028
1029     // Write named metadata operands.
1030     for (const MDNode *N : NMD.operands())
1031       Record.push_back(VE.getMetadataID(N));
1032     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1033     Record.clear();
1034   }
1035
1036   Stream.ExitBlock();
1037 }
1038
1039 static void WriteFunctionLocalMetadata(const Function &F,
1040                                        const ValueEnumerator &VE,
1041                                        BitstreamWriter &Stream) {
1042   bool StartedMetadataBlock = false;
1043   SmallVector<uint64_t, 64> Record;
1044   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
1045       VE.getFunctionLocalMDs();
1046   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1047     assert(MDs[i] && "Expected valid function-local metadata");
1048     if (!StartedMetadataBlock) {
1049       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1050       StartedMetadataBlock = true;
1051     }
1052     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
1053   }
1054
1055   if (StartedMetadataBlock)
1056     Stream.ExitBlock();
1057 }
1058
1059 static void WriteMetadataAttachment(const Function &F,
1060                                     const ValueEnumerator &VE,
1061                                     BitstreamWriter &Stream) {
1062   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1063
1064   SmallVector<uint64_t, 64> Record;
1065
1066   // Write metadata attachments
1067   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1068   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1069
1070   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1071     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1072          I != E; ++I) {
1073       MDs.clear();
1074       I->getAllMetadataOtherThanDebugLoc(MDs);
1075
1076       // If no metadata, ignore instruction.
1077       if (MDs.empty()) continue;
1078
1079       Record.push_back(VE.getInstructionID(I));
1080
1081       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1082         Record.push_back(MDs[i].first);
1083         Record.push_back(VE.getMetadataID(MDs[i].second));
1084       }
1085       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1086       Record.clear();
1087     }
1088
1089   Stream.ExitBlock();
1090 }
1091
1092 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
1093   SmallVector<uint64_t, 64> Record;
1094
1095   // Write metadata kinds
1096   // METADATA_KIND - [n x [id, name]]
1097   SmallVector<StringRef, 8> Names;
1098   M->getMDKindNames(Names);
1099
1100   if (Names.empty()) return;
1101
1102   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1103
1104   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1105     Record.push_back(MDKindID);
1106     StringRef KName = Names[MDKindID];
1107     Record.append(KName.begin(), KName.end());
1108
1109     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1110     Record.clear();
1111   }
1112
1113   Stream.ExitBlock();
1114 }
1115
1116 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1117   if ((int64_t)V >= 0)
1118     Vals.push_back(V << 1);
1119   else
1120     Vals.push_back((-V << 1) | 1);
1121 }
1122
1123 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
1124                            const ValueEnumerator &VE,
1125                            BitstreamWriter &Stream, bool isGlobal) {
1126   if (FirstVal == LastVal) return;
1127
1128   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
1129
1130   unsigned AggregateAbbrev = 0;
1131   unsigned String8Abbrev = 0;
1132   unsigned CString7Abbrev = 0;
1133   unsigned CString6Abbrev = 0;
1134   // If this is a constant pool for the module, emit module-specific abbrevs.
1135   if (isGlobal) {
1136     // Abbrev for CST_CODE_AGGREGATE.
1137     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1138     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
1139     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1140     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
1141     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
1142
1143     // Abbrev for CST_CODE_STRING.
1144     Abbv = new BitCodeAbbrev();
1145     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
1146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1148     String8Abbrev = Stream.EmitAbbrev(Abbv);
1149     // Abbrev for CST_CODE_CSTRING.
1150     Abbv = new BitCodeAbbrev();
1151     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1152     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1153     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1154     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1155     // Abbrev for CST_CODE_CSTRING.
1156     Abbv = new BitCodeAbbrev();
1157     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1159     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1160     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1161   }
1162
1163   SmallVector<uint64_t, 64> Record;
1164
1165   const ValueEnumerator::ValueList &Vals = VE.getValues();
1166   Type *LastTy = nullptr;
1167   for (unsigned i = FirstVal; i != LastVal; ++i) {
1168     const Value *V = Vals[i].first;
1169     // If we need to switch types, do so now.
1170     if (V->getType() != LastTy) {
1171       LastTy = V->getType();
1172       Record.push_back(VE.getTypeID(LastTy));
1173       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1174                         CONSTANTS_SETTYPE_ABBREV);
1175       Record.clear();
1176     }
1177
1178     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1179       Record.push_back(unsigned(IA->hasSideEffects()) |
1180                        unsigned(IA->isAlignStack()) << 1 |
1181                        unsigned(IA->getDialect()&1) << 2);
1182
1183       // Add the asm string.
1184       const std::string &AsmStr = IA->getAsmString();
1185       Record.push_back(AsmStr.size());
1186       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1187         Record.push_back(AsmStr[i]);
1188
1189       // Add the constraint string.
1190       const std::string &ConstraintStr = IA->getConstraintString();
1191       Record.push_back(ConstraintStr.size());
1192       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1193         Record.push_back(ConstraintStr[i]);
1194       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1195       Record.clear();
1196       continue;
1197     }
1198     const Constant *C = cast<Constant>(V);
1199     unsigned Code = -1U;
1200     unsigned AbbrevToUse = 0;
1201     if (C->isNullValue()) {
1202       Code = bitc::CST_CODE_NULL;
1203     } else if (isa<UndefValue>(C)) {
1204       Code = bitc::CST_CODE_UNDEF;
1205     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1206       if (IV->getBitWidth() <= 64) {
1207         uint64_t V = IV->getSExtValue();
1208         emitSignedInt64(Record, V);
1209         Code = bitc::CST_CODE_INTEGER;
1210         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1211       } else {                             // Wide integers, > 64 bits in size.
1212         // We have an arbitrary precision integer value to write whose
1213         // bit width is > 64. However, in canonical unsigned integer
1214         // format it is likely that the high bits are going to be zero.
1215         // So, we only write the number of active words.
1216         unsigned NWords = IV->getValue().getActiveWords();
1217         const uint64_t *RawWords = IV->getValue().getRawData();
1218         for (unsigned i = 0; i != NWords; ++i) {
1219           emitSignedInt64(Record, RawWords[i]);
1220         }
1221         Code = bitc::CST_CODE_WIDE_INTEGER;
1222       }
1223     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1224       Code = bitc::CST_CODE_FLOAT;
1225       Type *Ty = CFP->getType();
1226       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1227         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1228       } else if (Ty->isX86_FP80Ty()) {
1229         // api needed to prevent premature destruction
1230         // bits are not in the same order as a normal i80 APInt, compensate.
1231         APInt api = CFP->getValueAPF().bitcastToAPInt();
1232         const uint64_t *p = api.getRawData();
1233         Record.push_back((p[1] << 48) | (p[0] >> 16));
1234         Record.push_back(p[0] & 0xffffLL);
1235       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1236         APInt api = CFP->getValueAPF().bitcastToAPInt();
1237         const uint64_t *p = api.getRawData();
1238         Record.push_back(p[0]);
1239         Record.push_back(p[1]);
1240       } else {
1241         assert (0 && "Unknown FP type!");
1242       }
1243     } else if (isa<ConstantDataSequential>(C) &&
1244                cast<ConstantDataSequential>(C)->isString()) {
1245       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1246       // Emit constant strings specially.
1247       unsigned NumElts = Str->getNumElements();
1248       // If this is a null-terminated string, use the denser CSTRING encoding.
1249       if (Str->isCString()) {
1250         Code = bitc::CST_CODE_CSTRING;
1251         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1252       } else {
1253         Code = bitc::CST_CODE_STRING;
1254         AbbrevToUse = String8Abbrev;
1255       }
1256       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1257       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1258       for (unsigned i = 0; i != NumElts; ++i) {
1259         unsigned char V = Str->getElementAsInteger(i);
1260         Record.push_back(V);
1261         isCStr7 &= (V & 128) == 0;
1262         if (isCStrChar6)
1263           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1264       }
1265
1266       if (isCStrChar6)
1267         AbbrevToUse = CString6Abbrev;
1268       else if (isCStr7)
1269         AbbrevToUse = CString7Abbrev;
1270     } else if (const ConstantDataSequential *CDS =
1271                   dyn_cast<ConstantDataSequential>(C)) {
1272       Code = bitc::CST_CODE_DATA;
1273       Type *EltTy = CDS->getType()->getElementType();
1274       if (isa<IntegerType>(EltTy)) {
1275         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1276           Record.push_back(CDS->getElementAsInteger(i));
1277       } else if (EltTy->isFloatTy()) {
1278         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1279           union { float F; uint32_t I; };
1280           F = CDS->getElementAsFloat(i);
1281           Record.push_back(I);
1282         }
1283       } else {
1284         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1285         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1286           union { double F; uint64_t I; };
1287           F = CDS->getElementAsDouble(i);
1288           Record.push_back(I);
1289         }
1290       }
1291     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1292                isa<ConstantVector>(C)) {
1293       Code = bitc::CST_CODE_AGGREGATE;
1294       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1295         Record.push_back(VE.getValueID(C->getOperand(i)));
1296       AbbrevToUse = AggregateAbbrev;
1297     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1298       switch (CE->getOpcode()) {
1299       default:
1300         if (Instruction::isCast(CE->getOpcode())) {
1301           Code = bitc::CST_CODE_CE_CAST;
1302           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1303           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1304           Record.push_back(VE.getValueID(C->getOperand(0)));
1305           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1306         } else {
1307           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1308           Code = bitc::CST_CODE_CE_BINOP;
1309           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1310           Record.push_back(VE.getValueID(C->getOperand(0)));
1311           Record.push_back(VE.getValueID(C->getOperand(1)));
1312           uint64_t Flags = GetOptimizationFlags(CE);
1313           if (Flags != 0)
1314             Record.push_back(Flags);
1315         }
1316         break;
1317       case Instruction::GetElementPtr:
1318         Code = bitc::CST_CODE_CE_GEP;
1319         if (cast<GEPOperator>(C)->isInBounds())
1320           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1321         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1322           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1323           Record.push_back(VE.getValueID(C->getOperand(i)));
1324         }
1325         break;
1326       case Instruction::Select:
1327         Code = bitc::CST_CODE_CE_SELECT;
1328         Record.push_back(VE.getValueID(C->getOperand(0)));
1329         Record.push_back(VE.getValueID(C->getOperand(1)));
1330         Record.push_back(VE.getValueID(C->getOperand(2)));
1331         break;
1332       case Instruction::ExtractElement:
1333         Code = bitc::CST_CODE_CE_EXTRACTELT;
1334         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1335         Record.push_back(VE.getValueID(C->getOperand(0)));
1336         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1337         Record.push_back(VE.getValueID(C->getOperand(1)));
1338         break;
1339       case Instruction::InsertElement:
1340         Code = bitc::CST_CODE_CE_INSERTELT;
1341         Record.push_back(VE.getValueID(C->getOperand(0)));
1342         Record.push_back(VE.getValueID(C->getOperand(1)));
1343         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1344         Record.push_back(VE.getValueID(C->getOperand(2)));
1345         break;
1346       case Instruction::ShuffleVector:
1347         // If the return type and argument types are the same, this is a
1348         // standard shufflevector instruction.  If the types are different,
1349         // then the shuffle is widening or truncating the input vectors, and
1350         // the argument type must also be encoded.
1351         if (C->getType() == C->getOperand(0)->getType()) {
1352           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1353         } else {
1354           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1355           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1356         }
1357         Record.push_back(VE.getValueID(C->getOperand(0)));
1358         Record.push_back(VE.getValueID(C->getOperand(1)));
1359         Record.push_back(VE.getValueID(C->getOperand(2)));
1360         break;
1361       case Instruction::ICmp:
1362       case Instruction::FCmp:
1363         Code = bitc::CST_CODE_CE_CMP;
1364         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1365         Record.push_back(VE.getValueID(C->getOperand(0)));
1366         Record.push_back(VE.getValueID(C->getOperand(1)));
1367         Record.push_back(CE->getPredicate());
1368         break;
1369       }
1370     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1371       Code = bitc::CST_CODE_BLOCKADDRESS;
1372       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1373       Record.push_back(VE.getValueID(BA->getFunction()));
1374       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1375     } else {
1376 #ifndef NDEBUG
1377       C->dump();
1378 #endif
1379       llvm_unreachable("Unknown constant!");
1380     }
1381     Stream.EmitRecord(Code, Record, AbbrevToUse);
1382     Record.clear();
1383   }
1384
1385   Stream.ExitBlock();
1386 }
1387
1388 static void WriteModuleConstants(const ValueEnumerator &VE,
1389                                  BitstreamWriter &Stream) {
1390   const ValueEnumerator::ValueList &Vals = VE.getValues();
1391
1392   // Find the first constant to emit, which is the first non-globalvalue value.
1393   // We know globalvalues have been emitted by WriteModuleInfo.
1394   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1395     if (!isa<GlobalValue>(Vals[i].first)) {
1396       WriteConstants(i, Vals.size(), VE, Stream, true);
1397       return;
1398     }
1399   }
1400 }
1401
1402 /// PushValueAndType - The file has to encode both the value and type id for
1403 /// many values, because we need to know what type to create for forward
1404 /// references.  However, most operands are not forward references, so this type
1405 /// field is not needed.
1406 ///
1407 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1408 /// instruction ID, then it is a forward reference, and it also includes the
1409 /// type ID.  The value ID that is written is encoded relative to the InstID.
1410 static bool PushValueAndType(const Value *V, unsigned InstID,
1411                              SmallVectorImpl<unsigned> &Vals,
1412                              ValueEnumerator &VE) {
1413   unsigned ValID = VE.getValueID(V);
1414   // Make encoding relative to the InstID.
1415   Vals.push_back(InstID - ValID);
1416   if (ValID >= InstID) {
1417     Vals.push_back(VE.getTypeID(V->getType()));
1418     return true;
1419   }
1420   return false;
1421 }
1422
1423 /// pushValue - Like PushValueAndType, but where the type of the value is
1424 /// omitted (perhaps it was already encoded in an earlier operand).
1425 static void pushValue(const Value *V, unsigned InstID,
1426                       SmallVectorImpl<unsigned> &Vals,
1427                       ValueEnumerator &VE) {
1428   unsigned ValID = VE.getValueID(V);
1429   Vals.push_back(InstID - ValID);
1430 }
1431
1432 static void pushValueSigned(const Value *V, unsigned InstID,
1433                             SmallVectorImpl<uint64_t> &Vals,
1434                             ValueEnumerator &VE) {
1435   unsigned ValID = VE.getValueID(V);
1436   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1437   emitSignedInt64(Vals, diff);
1438 }
1439
1440 /// WriteInstruction - Emit an instruction to the specified stream.
1441 static void WriteInstruction(const Instruction &I, unsigned InstID,
1442                              ValueEnumerator &VE, BitstreamWriter &Stream,
1443                              SmallVectorImpl<unsigned> &Vals) {
1444   unsigned Code = 0;
1445   unsigned AbbrevToUse = 0;
1446   VE.setInstructionID(&I);
1447   switch (I.getOpcode()) {
1448   default:
1449     if (Instruction::isCast(I.getOpcode())) {
1450       Code = bitc::FUNC_CODE_INST_CAST;
1451       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1452         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1453       Vals.push_back(VE.getTypeID(I.getType()));
1454       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1455     } else {
1456       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1457       Code = bitc::FUNC_CODE_INST_BINOP;
1458       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1459         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1460       pushValue(I.getOperand(1), InstID, Vals, VE);
1461       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1462       uint64_t Flags = GetOptimizationFlags(&I);
1463       if (Flags != 0) {
1464         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1465           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1466         Vals.push_back(Flags);
1467       }
1468     }
1469     break;
1470
1471   case Instruction::GetElementPtr:
1472     Code = bitc::FUNC_CODE_INST_GEP;
1473     if (cast<GEPOperator>(&I)->isInBounds())
1474       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1475     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1476       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1477     break;
1478   case Instruction::ExtractValue: {
1479     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1480     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1481     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1482     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1483       Vals.push_back(*i);
1484     break;
1485   }
1486   case Instruction::InsertValue: {
1487     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1488     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1489     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1490     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1491     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1492       Vals.push_back(*i);
1493     break;
1494   }
1495   case Instruction::Select:
1496     Code = bitc::FUNC_CODE_INST_VSELECT;
1497     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1498     pushValue(I.getOperand(2), InstID, Vals, VE);
1499     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1500     break;
1501   case Instruction::ExtractElement:
1502     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1503     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1504     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1505     break;
1506   case Instruction::InsertElement:
1507     Code = bitc::FUNC_CODE_INST_INSERTELT;
1508     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1509     pushValue(I.getOperand(1), InstID, Vals, VE);
1510     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1511     break;
1512   case Instruction::ShuffleVector:
1513     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1514     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1515     pushValue(I.getOperand(1), InstID, Vals, VE);
1516     pushValue(I.getOperand(2), InstID, Vals, VE);
1517     break;
1518   case Instruction::ICmp:
1519   case Instruction::FCmp:
1520     // compare returning Int1Ty or vector of Int1Ty
1521     Code = bitc::FUNC_CODE_INST_CMP2;
1522     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1523     pushValue(I.getOperand(1), InstID, Vals, VE);
1524     Vals.push_back(cast<CmpInst>(I).getPredicate());
1525     break;
1526
1527   case Instruction::Ret:
1528     {
1529       Code = bitc::FUNC_CODE_INST_RET;
1530       unsigned NumOperands = I.getNumOperands();
1531       if (NumOperands == 0)
1532         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1533       else if (NumOperands == 1) {
1534         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1535           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1536       } else {
1537         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1538           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1539       }
1540     }
1541     break;
1542   case Instruction::Br:
1543     {
1544       Code = bitc::FUNC_CODE_INST_BR;
1545       const BranchInst &II = cast<BranchInst>(I);
1546       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1547       if (II.isConditional()) {
1548         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1549         pushValue(II.getCondition(), InstID, Vals, VE);
1550       }
1551     }
1552     break;
1553   case Instruction::Switch:
1554     {
1555       Code = bitc::FUNC_CODE_INST_SWITCH;
1556       const SwitchInst &SI = cast<SwitchInst>(I);
1557       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1558       pushValue(SI.getCondition(), InstID, Vals, VE);
1559       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1560       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1561            i != e; ++i) {
1562         Vals.push_back(VE.getValueID(i.getCaseValue()));
1563         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1564       }
1565     }
1566     break;
1567   case Instruction::IndirectBr:
1568     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1569     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1570     // Encode the address operand as relative, but not the basic blocks.
1571     pushValue(I.getOperand(0), InstID, Vals, VE);
1572     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1573       Vals.push_back(VE.getValueID(I.getOperand(i)));
1574     break;
1575
1576   case Instruction::Invoke: {
1577     const InvokeInst *II = cast<InvokeInst>(&I);
1578     const Value *Callee(II->getCalledValue());
1579     PointerType *PTy = cast<PointerType>(Callee->getType());
1580     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1581     Code = bitc::FUNC_CODE_INST_INVOKE;
1582
1583     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1584     Vals.push_back(II->getCallingConv());
1585     Vals.push_back(VE.getValueID(II->getNormalDest()));
1586     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1587     PushValueAndType(Callee, InstID, Vals, VE);
1588
1589     // Emit value #'s for the fixed parameters.
1590     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1591       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1592
1593     // Emit type/value pairs for varargs params.
1594     if (FTy->isVarArg()) {
1595       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1596            i != e; ++i)
1597         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1598     }
1599     break;
1600   }
1601   case Instruction::Resume:
1602     Code = bitc::FUNC_CODE_INST_RESUME;
1603     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1604     break;
1605   case Instruction::Unreachable:
1606     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1607     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1608     break;
1609
1610   case Instruction::PHI: {
1611     const PHINode &PN = cast<PHINode>(I);
1612     Code = bitc::FUNC_CODE_INST_PHI;
1613     // With the newer instruction encoding, forward references could give
1614     // negative valued IDs.  This is most common for PHIs, so we use
1615     // signed VBRs.
1616     SmallVector<uint64_t, 128> Vals64;
1617     Vals64.push_back(VE.getTypeID(PN.getType()));
1618     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1619       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1620       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1621     }
1622     // Emit a Vals64 vector and exit.
1623     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1624     Vals64.clear();
1625     return;
1626   }
1627
1628   case Instruction::LandingPad: {
1629     const LandingPadInst &LP = cast<LandingPadInst>(I);
1630     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1631     Vals.push_back(VE.getTypeID(LP.getType()));
1632     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1633     Vals.push_back(LP.isCleanup());
1634     Vals.push_back(LP.getNumClauses());
1635     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1636       if (LP.isCatch(I))
1637         Vals.push_back(LandingPadInst::Catch);
1638       else
1639         Vals.push_back(LandingPadInst::Filter);
1640       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1641     }
1642     break;
1643   }
1644
1645   case Instruction::Alloca: {
1646     Code = bitc::FUNC_CODE_INST_ALLOCA;
1647     Vals.push_back(VE.getTypeID(I.getType()));
1648     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1649     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1650     const AllocaInst &AI = cast<AllocaInst>(I);
1651     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1652     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1653            "not enough bits for maximum alignment");
1654     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1655     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1656     Vals.push_back(AlignRecord);
1657     break;
1658   }
1659
1660   case Instruction::Load:
1661     if (cast<LoadInst>(I).isAtomic()) {
1662       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1663       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1664     } else {
1665       Code = bitc::FUNC_CODE_INST_LOAD;
1666       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1667         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1668     }
1669     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1670     Vals.push_back(cast<LoadInst>(I).isVolatile());
1671     if (cast<LoadInst>(I).isAtomic()) {
1672       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1673       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1674     }
1675     break;
1676   case Instruction::Store:
1677     if (cast<StoreInst>(I).isAtomic())
1678       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1679     else
1680       Code = bitc::FUNC_CODE_INST_STORE;
1681     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1682     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1683     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1684     Vals.push_back(cast<StoreInst>(I).isVolatile());
1685     if (cast<StoreInst>(I).isAtomic()) {
1686       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1687       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1688     }
1689     break;
1690   case Instruction::AtomicCmpXchg:
1691     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1692     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1693     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1694     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1695     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1696     Vals.push_back(GetEncodedOrdering(
1697                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1698     Vals.push_back(GetEncodedSynchScope(
1699                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1700     Vals.push_back(GetEncodedOrdering(
1701                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1702     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1703     break;
1704   case Instruction::AtomicRMW:
1705     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1706     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1707     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1708     Vals.push_back(GetEncodedRMWOperation(
1709                      cast<AtomicRMWInst>(I).getOperation()));
1710     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1711     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1712     Vals.push_back(GetEncodedSynchScope(
1713                      cast<AtomicRMWInst>(I).getSynchScope()));
1714     break;
1715   case Instruction::Fence:
1716     Code = bitc::FUNC_CODE_INST_FENCE;
1717     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1718     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1719     break;
1720   case Instruction::Call: {
1721     const CallInst &CI = cast<CallInst>(I);
1722     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1723     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1724
1725     Code = bitc::FUNC_CODE_INST_CALL;
1726
1727     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1728     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1729                    unsigned(CI.isMustTailCall()) << 14);
1730     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1731
1732     // Emit value #'s for the fixed parameters.
1733     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1734       // Check for labels (can happen with asm labels).
1735       if (FTy->getParamType(i)->isLabelTy())
1736         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1737       else
1738         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1739     }
1740
1741     // Emit type/value pairs for varargs params.
1742     if (FTy->isVarArg()) {
1743       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1744            i != e; ++i)
1745         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1746     }
1747     break;
1748   }
1749   case Instruction::VAArg:
1750     Code = bitc::FUNC_CODE_INST_VAARG;
1751     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1752     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1753     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1754     break;
1755   }
1756
1757   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1758   Vals.clear();
1759 }
1760
1761 // Emit names for globals/functions etc.
1762 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1763                                   const ValueEnumerator &VE,
1764                                   BitstreamWriter &Stream) {
1765   if (VST.empty()) return;
1766   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1767
1768   // FIXME: Set up the abbrev, we know how many values there are!
1769   // FIXME: We know if the type names can use 7-bit ascii.
1770   SmallVector<unsigned, 64> NameVals;
1771
1772   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1773        SI != SE; ++SI) {
1774
1775     const ValueName &Name = *SI;
1776
1777     // Figure out the encoding to use for the name.
1778     bool is7Bit = true;
1779     bool isChar6 = true;
1780     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1781          C != E; ++C) {
1782       if (isChar6)
1783         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1784       if ((unsigned char)*C & 128) {
1785         is7Bit = false;
1786         break;  // don't bother scanning the rest.
1787       }
1788     }
1789
1790     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1791
1792     // VST_ENTRY:   [valueid, namechar x N]
1793     // VST_BBENTRY: [bbid, namechar x N]
1794     unsigned Code;
1795     if (isa<BasicBlock>(SI->getValue())) {
1796       Code = bitc::VST_CODE_BBENTRY;
1797       if (isChar6)
1798         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1799     } else {
1800       Code = bitc::VST_CODE_ENTRY;
1801       if (isChar6)
1802         AbbrevToUse = VST_ENTRY_6_ABBREV;
1803       else if (is7Bit)
1804         AbbrevToUse = VST_ENTRY_7_ABBREV;
1805     }
1806
1807     NameVals.push_back(VE.getValueID(SI->getValue()));
1808     for (const char *P = Name.getKeyData(),
1809          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1810       NameVals.push_back((unsigned char)*P);
1811
1812     // Emit the finished record.
1813     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1814     NameVals.clear();
1815   }
1816   Stream.ExitBlock();
1817 }
1818
1819 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1820                          BitstreamWriter &Stream) {
1821   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1822   unsigned Code;
1823   if (isa<BasicBlock>(Order.V))
1824     Code = bitc::USELIST_CODE_BB;
1825   else
1826     Code = bitc::USELIST_CODE_DEFAULT;
1827
1828   SmallVector<uint64_t, 64> Record;
1829   for (unsigned I : Order.Shuffle)
1830     Record.push_back(I);
1831   Record.push_back(VE.getValueID(Order.V));
1832   Stream.EmitRecord(Code, Record);
1833 }
1834
1835 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1836                               BitstreamWriter &Stream) {
1837   auto hasMore = [&]() {
1838     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1839   };
1840   if (!hasMore())
1841     // Nothing to do.
1842     return;
1843
1844   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1845   while (hasMore()) {
1846     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1847     VE.UseListOrders.pop_back();
1848   }
1849   Stream.ExitBlock();
1850 }
1851
1852 /// WriteFunction - Emit a function body to the module stream.
1853 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1854                           BitstreamWriter &Stream) {
1855   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1856   VE.incorporateFunction(F);
1857
1858   SmallVector<unsigned, 64> Vals;
1859
1860   // Emit the number of basic blocks, so the reader can create them ahead of
1861   // time.
1862   Vals.push_back(VE.getBasicBlocks().size());
1863   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1864   Vals.clear();
1865
1866   // If there are function-local constants, emit them now.
1867   unsigned CstStart, CstEnd;
1868   VE.getFunctionConstantRange(CstStart, CstEnd);
1869   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1870
1871   // If there is function-local metadata, emit it now.
1872   WriteFunctionLocalMetadata(F, VE, Stream);
1873
1874   // Keep a running idea of what the instruction ID is.
1875   unsigned InstID = CstEnd;
1876
1877   bool NeedsMetadataAttachment = false;
1878
1879   DebugLoc LastDL;
1880
1881   // Finally, emit all the instructions, in order.
1882   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1883     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1884          I != E; ++I) {
1885       WriteInstruction(*I, InstID, VE, Stream, Vals);
1886
1887       if (!I->getType()->isVoidTy())
1888         ++InstID;
1889
1890       // If the instruction has metadata, write a metadata attachment later.
1891       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1892
1893       // If the instruction has a debug location, emit it.
1894       DebugLoc DL = I->getDebugLoc();
1895       if (DL.isUnknown()) {
1896         // nothing todo.
1897       } else if (DL == LastDL) {
1898         // Just repeat the same debug loc as last time.
1899         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1900       } else {
1901         MDNode *Scope, *IA;
1902         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1903         assert(Scope && "Expected valid scope");
1904
1905         Vals.push_back(DL.getLine());
1906         Vals.push_back(DL.getCol());
1907         Vals.push_back(VE.getMetadataOrNullID(Scope));
1908         Vals.push_back(VE.getMetadataOrNullID(IA));
1909         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1910         Vals.clear();
1911
1912         LastDL = DL;
1913       }
1914     }
1915
1916   // Emit names for all the instructions etc.
1917   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1918
1919   if (NeedsMetadataAttachment)
1920     WriteMetadataAttachment(F, VE, Stream);
1921   if (shouldPreserveBitcodeUseListOrder())
1922     WriteUseListBlock(&F, VE, Stream);
1923   VE.purgeFunction();
1924   Stream.ExitBlock();
1925 }
1926
1927 // Emit blockinfo, which defines the standard abbreviations etc.
1928 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1929   // We only want to emit block info records for blocks that have multiple
1930   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1931   // Other blocks can define their abbrevs inline.
1932   Stream.EnterBlockInfoBlock(2);
1933
1934   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1935     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1936     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1937     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1938     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1939     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1940     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1941                                    Abbv) != VST_ENTRY_8_ABBREV)
1942       llvm_unreachable("Unexpected abbrev ordering!");
1943   }
1944
1945   { // 7-bit fixed width VST_ENTRY strings.
1946     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1947     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1948     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1949     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1950     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1951     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1952                                    Abbv) != VST_ENTRY_7_ABBREV)
1953       llvm_unreachable("Unexpected abbrev ordering!");
1954   }
1955   { // 6-bit char6 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::Char6));
1961     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1962                                    Abbv) != VST_ENTRY_6_ABBREV)
1963       llvm_unreachable("Unexpected abbrev ordering!");
1964   }
1965   { // 6-bit char6 VST_BBENTRY strings.
1966     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1967     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
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_BBENTRY_6_ABBREV)
1973       llvm_unreachable("Unexpected abbrev ordering!");
1974   }
1975
1976
1977
1978   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1979     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1980     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1981     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1982                               Log2_32_Ceil(VE.getTypes().size()+1)));
1983     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1984                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1985       llvm_unreachable("Unexpected abbrev ordering!");
1986   }
1987
1988   { // INTEGER abbrev for CONSTANTS_BLOCK.
1989     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1990     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1991     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1992     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1993                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1994       llvm_unreachable("Unexpected abbrev ordering!");
1995   }
1996
1997   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1998     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1999     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
2000     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
2001     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
2002                               Log2_32_Ceil(VE.getTypes().size()+1)));
2003     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
2004
2005     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2006                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
2007       llvm_unreachable("Unexpected abbrev ordering!");
2008   }
2009   { // NULL abbrev for CONSTANTS_BLOCK.
2010     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2011     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
2012     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
2013                                    Abbv) != CONSTANTS_NULL_Abbrev)
2014       llvm_unreachable("Unexpected abbrev ordering!");
2015   }
2016
2017   // FIXME: This should only use space for first class types!
2018
2019   { // INST_LOAD abbrev for FUNCTION_BLOCK.
2020     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2021     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
2022     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
2023     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
2024     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
2025     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2026                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
2027       llvm_unreachable("Unexpected abbrev ordering!");
2028   }
2029   { // INST_BINOP abbrev for FUNCTION_BLOCK.
2030     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2031     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
2032     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
2033     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
2034     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
2035     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2036                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
2037       llvm_unreachable("Unexpected abbrev ordering!");
2038   }
2039   { // INST_BINOP_FLAGS 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     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
2046     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2047                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
2048       llvm_unreachable("Unexpected abbrev ordering!");
2049   }
2050   { // INST_CAST abbrev for FUNCTION_BLOCK.
2051     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2052     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
2053     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
2054     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
2055                               Log2_32_Ceil(VE.getTypes().size()+1)));
2056     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
2057     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2058                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
2059       llvm_unreachable("Unexpected abbrev ordering!");
2060   }
2061
2062   { // INST_RET abbrev for FUNCTION_BLOCK.
2063     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2064     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2065     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2066                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
2067       llvm_unreachable("Unexpected abbrev ordering!");
2068   }
2069   { // INST_RET abbrev for FUNCTION_BLOCK.
2070     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2071     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
2072     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
2073     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2074                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
2075       llvm_unreachable("Unexpected abbrev ordering!");
2076   }
2077   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
2078     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2079     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
2080     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
2081                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
2082       llvm_unreachable("Unexpected abbrev ordering!");
2083   }
2084
2085   Stream.ExitBlock();
2086 }
2087
2088 /// WriteModule - Emit the specified module to the bitstream.
2089 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
2090   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
2091
2092   SmallVector<unsigned, 1> Vals;
2093   unsigned CurVersion = 1;
2094   Vals.push_back(CurVersion);
2095   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
2096
2097   // Analyze the module, enumerating globals, functions, etc.
2098   ValueEnumerator VE(*M);
2099
2100   // Emit blockinfo, which defines the standard abbreviations etc.
2101   WriteBlockInfo(VE, Stream);
2102
2103   // Emit information about attribute groups.
2104   WriteAttributeGroupTable(VE, Stream);
2105
2106   // Emit information about parameter attributes.
2107   WriteAttributeTable(VE, Stream);
2108
2109   // Emit information describing all of the types in the module.
2110   WriteTypeTable(VE, Stream);
2111
2112   writeComdats(VE, Stream);
2113
2114   // Emit top-level description of module, including target triple, inline asm,
2115   // descriptors for global variables, and function prototype info.
2116   WriteModuleInfo(M, VE, Stream);
2117
2118   // Emit constants.
2119   WriteModuleConstants(VE, Stream);
2120
2121   // Emit metadata.
2122   WriteModuleMetadata(M, VE, Stream);
2123
2124   // Emit metadata.
2125   WriteModuleMetadataStore(M, Stream);
2126
2127   // Emit names for globals/functions etc.
2128   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
2129
2130   // Emit module-level use-lists.
2131   if (shouldPreserveBitcodeUseListOrder())
2132     WriteUseListBlock(nullptr, VE, Stream);
2133
2134   // Emit function bodies.
2135   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
2136     if (!F->isDeclaration())
2137       WriteFunction(*F, VE, Stream);
2138
2139   Stream.ExitBlock();
2140 }
2141
2142 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
2143 /// header and trailer to make it compatible with the system archiver.  To do
2144 /// this we emit the following header, and then emit a trailer that pads the
2145 /// file out to be a multiple of 16 bytes.
2146 ///
2147 /// struct bc_header {
2148 ///   uint32_t Magic;         // 0x0B17C0DE
2149 ///   uint32_t Version;       // Version, currently always 0.
2150 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
2151 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2152 ///   uint32_t CPUType;       // CPU specifier.
2153 ///   ... potentially more later ...
2154 /// };
2155 enum {
2156   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2157   DarwinBCHeaderSize = 5*4
2158 };
2159
2160 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2161                                uint32_t &Position) {
2162   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2163   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2164   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2165   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2166   Position += 4;
2167 }
2168
2169 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2170                                          const Triple &TT) {
2171   unsigned CPUType = ~0U;
2172
2173   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2174   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2175   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2176   // specific constants here because they are implicitly part of the Darwin ABI.
2177   enum {
2178     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2179     DARWIN_CPU_TYPE_X86        = 7,
2180     DARWIN_CPU_TYPE_ARM        = 12,
2181     DARWIN_CPU_TYPE_POWERPC    = 18
2182   };
2183
2184   Triple::ArchType Arch = TT.getArch();
2185   if (Arch == Triple::x86_64)
2186     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2187   else if (Arch == Triple::x86)
2188     CPUType = DARWIN_CPU_TYPE_X86;
2189   else if (Arch == Triple::ppc)
2190     CPUType = DARWIN_CPU_TYPE_POWERPC;
2191   else if (Arch == Triple::ppc64)
2192     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2193   else if (Arch == Triple::arm || Arch == Triple::thumb)
2194     CPUType = DARWIN_CPU_TYPE_ARM;
2195
2196   // Traditional Bitcode starts after header.
2197   assert(Buffer.size() >= DarwinBCHeaderSize &&
2198          "Expected header size to be reserved");
2199   unsigned BCOffset = DarwinBCHeaderSize;
2200   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2201
2202   // Write the magic and version.
2203   unsigned Position = 0;
2204   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2205   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2206   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2207   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2208   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2209
2210   // If the file is not a multiple of 16 bytes, insert dummy padding.
2211   while (Buffer.size() & 15)
2212     Buffer.push_back(0);
2213 }
2214
2215 /// WriteBitcodeToFile - Write the specified module to the specified output
2216 /// stream.
2217 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2218   SmallVector<char, 0> Buffer;
2219   Buffer.reserve(256*1024);
2220
2221   // If this is darwin or another generic macho target, reserve space for the
2222   // header.
2223   Triple TT(M->getTargetTriple());
2224   if (TT.isOSDarwin())
2225     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2226
2227   // Emit the module into the buffer.
2228   {
2229     BitstreamWriter Stream(Buffer);
2230
2231     // Emit the file header.
2232     Stream.Emit((unsigned)'B', 8);
2233     Stream.Emit((unsigned)'C', 8);
2234     Stream.Emit(0x0, 4);
2235     Stream.Emit(0xC, 4);
2236     Stream.Emit(0xE, 4);
2237     Stream.Emit(0xD, 4);
2238
2239     // Emit the module.
2240     WriteModule(M, Stream);
2241   }
2242
2243   if (TT.isOSDarwin())
2244     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2245
2246   // Write the generated bitstream to "Out".
2247   Out.write((char*)&Buffer.front(), Buffer.size());
2248 }