lib/Bitcode/Writer/BitcodeWriter.cpp

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