lib/Bitcode/Writer/BitcodeWriter.cpp

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