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 1;
 484   case GlobalValue::AppendingLinkage:
 485     return 2;
 486   case GlobalValue::InternalLinkage:
 487     return 3;
 488   case GlobalValue::LinkOnceAnyLinkage:
 489     return 4;
 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 10;
 498   case GlobalValue::LinkOnceODRLinkage:
 499     return 11;
 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<uint8_t, 64> Vals;
 553   for (const Comdat *C : VE.getComdats()) {
 554     // COMDAT: [selection_kind, name]
 555     Vals.push_back(getEncodedComdatSelectionKind(*C));
 556     Vals.push_back(C->getName().size());
 557     for (char Chr : C->getName())
 558       Vals.push_back((unsigned char)Chr);
 559     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
 560     Vals.clear();
 561   }
 562 }
 563
 564 // Emit top-level description of module, including target triple, inline asm,
 565 // descriptors for global variables, and function prototype info.
 566 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 567                             BitstreamWriter &Stream) {
 568   // Emit various pieces of data attached to a module.
 569   if (!M->getTargetTriple().empty())
 570     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 571                       0/*TODO*/, Stream);
 572   const std::string &DL = M->getDataLayoutStr();
 573   if (!DL.empty())
 574     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/, Stream);
 575   if (!M->getModuleInlineAsm().empty())
 576     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 577                       0/*TODO*/, Stream);
 578
 579   // Emit information about sections and GC, computing how many there are. Also
 580   // compute the maximum alignment value.
 581   std::map<std::string, unsigned> SectionMap;
 582   std::map<std::string, unsigned> GCMap;
 583   unsigned MaxAlignment = 0;
 584   unsigned MaxGlobalType = 0;
 585   for (const GlobalValue &GV : M->globals()) {
 586     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
 587     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
 588     if (GV.hasSection()) {
 589       // Give section names unique ID's.
 590       unsigned &Entry = SectionMap[GV.getSection()];
 591       if (!Entry) {
 592         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
 593                           0/*TODO*/, Stream);
 594         Entry = SectionMap.size();
 595       }
 596     }
 597   }
 598   for (const Function &F : *M) {
 599     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
 600     if (F.hasSection()) {
 601       // Give section names unique ID's.
 602       unsigned &Entry = SectionMap[F.getSection()];
 603       if (!Entry) {
 604         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
 605                           0/*TODO*/, Stream);
 606         Entry = SectionMap.size();
 607       }
 608     }
 609     if (F.hasGC()) {
 610       // Same for GC names.
 611       unsigned &Entry = GCMap[F.getGC()];
 612       if (!Entry) {
 613         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(),
 614                           0/*TODO*/, Stream);
 615         Entry = GCMap.size();
 616       }
 617     }
 618   }
 619
 620   // Emit abbrev for globals, now that we know # sections and max alignment.
 621   unsigned SimpleGVarAbbrev = 0;
 622   if (!M->global_empty()) {
 623     // Add an abbrev for common globals with no visibility or thread localness.
 624     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 625     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 626     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 627                               Log2_32_Ceil(MaxGlobalType+1)));
 628     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 629     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 630     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 631     if (MaxAlignment == 0)                                      // Alignment.
 632       Abbv->Add(BitCodeAbbrevOp(0));
 633     else {
 634       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 635       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 636                                Log2_32_Ceil(MaxEncAlignment+1)));
 637     }
 638     if (SectionMap.empty())                                    // Section.
 639       Abbv->Add(BitCodeAbbrevOp(0));
 640     else
 641       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 642                                Log2_32_Ceil(SectionMap.size()+1)));
 643     // Don't bother emitting vis + thread local.
 644     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 645   }
 646
 647   // Emit the global variable information.
 648   SmallVector<unsigned, 64> Vals;
 649   for (const GlobalVariable &GV : M->globals()) {
 650     unsigned AbbrevToUse = 0;
 651
 652     // GLOBALVAR: [type, isconst, initid,
 653     //             linkage, alignment, section, visibility, threadlocal,
 654     //             unnamed_addr, externally_initialized, dllstorageclass]
 655     Vals.push_back(VE.getTypeID(GV.getType()));
 656     Vals.push_back(GV.isConstant());
 657     Vals.push_back(GV.isDeclaration() ? 0 :
 658                    (VE.getValueID(GV.getInitializer()) + 1));
 659     Vals.push_back(getEncodedLinkage(GV));
 660     Vals.push_back(Log2_32(GV.getAlignment())+1);
 661     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
 662     if (GV.isThreadLocal() ||
 663         GV.getVisibility() != GlobalValue::DefaultVisibility ||
 664         GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
 665         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
 666         GV.hasComdat()) {
 667       Vals.push_back(getEncodedVisibility(GV));
 668       Vals.push_back(getEncodedThreadLocalMode(GV));
 669       Vals.push_back(GV.hasUnnamedAddr());
 670       Vals.push_back(GV.isExternallyInitialized());
 671       Vals.push_back(getEncodedDLLStorageClass(GV));
 672       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
 673     } else {
 674       AbbrevToUse = SimpleGVarAbbrev;
 675     }
 676
 677     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 678     Vals.clear();
 679   }
 680
 681   // Emit the function proto information.
 682   for (const Function &F : *M) {
 683     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
 684     //             section, visibility, gc, unnamed_addr, prologuedata,
 685     //             dllstorageclass, comdat, prefixdata]
 686     Vals.push_back(VE.getTypeID(F.getType()));
 687     Vals.push_back(F.getCallingConv());
 688     Vals.push_back(F.isDeclaration());
 689     Vals.push_back(getEncodedLinkage(F));
 690     Vals.push_back(VE.getAttributeID(F.getAttributes()));
 691     Vals.push_back(Log2_32(F.getAlignment())+1);
 692     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
 693     Vals.push_back(getEncodedVisibility(F));
 694     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
 695     Vals.push_back(F.hasUnnamedAddr());
 696     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
 697                                        : 0);
 698     Vals.push_back(getEncodedDLLStorageClass(F));
 699     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
 700     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
 701                                      : 0);
 702
 703     unsigned AbbrevToUse = 0;
 704     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 705     Vals.clear();
 706   }
 707
 708   // Emit the alias information.
 709   for (const GlobalAlias &A : M->aliases()) {
 710     // ALIAS: [alias type, aliasee val#, linkage, visibility]
 711     Vals.push_back(VE.getTypeID(A.getType()));
 712     Vals.push_back(VE.getValueID(A.getAliasee()));
 713     Vals.push_back(getEncodedLinkage(A));
 714     Vals.push_back(getEncodedVisibility(A));
 715     Vals.push_back(getEncodedDLLStorageClass(A));
 716     Vals.push_back(getEncodedThreadLocalMode(A));
 717     Vals.push_back(A.hasUnnamedAddr());
 718     unsigned AbbrevToUse = 0;
 719     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 720     Vals.clear();
 721   }
 722 }
 723
 724 static uint64_t GetOptimizationFlags(const Value *V) {
 725   uint64_t Flags = 0;
 726
 727   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
 728     if (OBO->hasNoSignedWrap())
 729       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 730     if (OBO->hasNoUnsignedWrap())
 731       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 732   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
 733     if (PEO->isExact())
 734       Flags |= 1 << bitc::PEO_EXACT;
 735   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
 736     if (FPMO->hasUnsafeAlgebra())
 737       Flags |= FastMathFlags::UnsafeAlgebra;
 738     if (FPMO->hasNoNaNs())
 739       Flags |= FastMathFlags::NoNaNs;
 740     if (FPMO->hasNoInfs())
 741       Flags |= FastMathFlags::NoInfs;
 742     if (FPMO->hasNoSignedZeros())
 743       Flags |= FastMathFlags::NoSignedZeros;
 744     if (FPMO->hasAllowReciprocal())
 745       Flags |= FastMathFlags::AllowReciprocal;
 746   }
 747
 748   return Flags;
 749 }
 750
 751 static void WriteValueAsMetadata(const ValueAsMetadata *MD,
 752                                  const ValueEnumerator &VE,
 753                                  BitstreamWriter &Stream,
 754                                  SmallVectorImpl<uint64_t> &Record) {
 755   // Mimic an MDNode with a value as one operand.
 756   Value *V = MD->getValue();
 757   Record.push_back(VE.getTypeID(V->getType()));
 758   Record.push_back(VE.getValueID(V));
 759   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
 760   Record.clear();
 761 }
 762
 763 static void WriteMDNode(const MDNode *N,
 764                         const ValueEnumerator &VE,
 765                         BitstreamWriter &Stream,
 766                         SmallVectorImpl<uint64_t> &Record) {
 767   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 768     Metadata *MD = N->getOperand(i);
 769     if (!MD) {
 770       Record.push_back(0);
 771       continue;
 772     }
 773     assert(!isa<LocalAsMetadata>(MD) && "Unexpected function-local metadata");
 774     Record.push_back(VE.getMetadataID(MD) + 1);
 775   }
 776   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
 777                                     : bitc::METADATA_NODE,
 778                     Record);
 779   Record.clear();
 780 }
 781
 782 static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
 783                             BitstreamWriter &Stream,
 784                             SmallVectorImpl<uint64_t> &Record,
 785                             unsigned Abbrev) {
 786   Record.push_back(N->isDistinct());
 787   Record.push_back(N->getLine());
 788   Record.push_back(N->getColumn());
 789   Record.push_back(VE.getMetadataID(N->getScope()));
 790
 791   // Always emit the inlined-at location, even though it's optional.
 792   if (Metadata *InlinedAt = N->getInlinedAt())
 793     Record.push_back(VE.getMetadataID(InlinedAt) + 1);
 794   else
 795     Record.push_back(0);
 796
 797   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
 798   Record.clear();
 799 }
 800
 801 static void WriteModuleMetadata(const Module *M,
 802                                 const ValueEnumerator &VE,
 803                                 BitstreamWriter &Stream) {
 804   const auto &MDs = VE.getMDs();
 805   if (MDs.empty() && M->named_metadata_empty())
 806     return;
 807
 808   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 809
 810   unsigned MDSAbbrev = 0;
 811   if (VE.hasMDString()) {
 812     // Abbrev for METADATA_STRING.
 813     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 814     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 815     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 817     MDSAbbrev = Stream.EmitAbbrev(Abbv);
 818   }
 819
 820   unsigned LocAbbrev = 0;
 821   if (VE.hasMDLocation()) {
 822     // Abbrev for METADATA_LOCATION.
 823     //
 824     // Assume the column is usually under 128, and always output the inlined-at
 825     // location (it's never more expensive than building an array size 1).
 826     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 827     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
 828     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 829     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 830     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
 831     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 832     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
 833     LocAbbrev = Stream.EmitAbbrev(Abbv);
 834   }
 835
 836   unsigned NameAbbrev = 0;
 837   if (!M->named_metadata_empty()) {
 838     // Abbrev for METADATA_NAME.
 839     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 840     Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
 841     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 842     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 843     NameAbbrev = Stream.EmitAbbrev(Abbv);
 844   }
 845
 846   SmallVector<uint64_t, 64> Record;
 847   for (const Metadata *MD : MDs) {
 848     if (const MDLocation *Loc = dyn_cast<MDLocation>(MD)) {
 849       WriteMDLocation(Loc, VE, Stream, Record, LocAbbrev);
 850       continue;
 851     }
 852     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
 853       WriteMDNode(N, VE, Stream, Record);
 854       continue;
 855     }
 856     if (const auto *MDC = dyn_cast<ConstantAsMetadata>(MD)) {
 857       WriteValueAsMetadata(MDC, VE, Stream, Record);
 858       continue;
 859     }
 860     const MDString *MDS = cast<MDString>(MD);
 861     // Code: [strchar x N]
 862     Record.append(MDS->bytes_begin(), MDS->bytes_end());
 863
 864     // Emit the finished record.
 865     Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 866     Record.clear();
 867   }
 868
 869   // Write named metadata.
 870   for (const NamedMDNode &NMD : M->named_metadata()) {
 871     // Write name.
 872     StringRef Str = NMD.getName();
 873     Record.append(Str.bytes_begin(), Str.bytes_end());
 874     Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
 875     Record.clear();
 876
 877     // Write named metadata operands.
 878     for (const MDNode *N : NMD.operands())
 879       Record.push_back(VE.getMetadataID(N));
 880     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 881     Record.clear();
 882   }
 883
 884   Stream.ExitBlock();
 885 }
 886
 887 static void WriteFunctionLocalMetadata(const Function &F,
 888                                        const ValueEnumerator &VE,
 889                                        BitstreamWriter &Stream) {
 890   bool StartedMetadataBlock = false;
 891   SmallVector<uint64_t, 64> Record;
 892   const SmallVectorImpl<const LocalAsMetadata *> &MDs =
 893       VE.getFunctionLocalMDs();
 894   for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 895     assert(MDs[i] && "Expected valid function-local metadata");
 896     if (!StartedMetadataBlock) {
 897       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 898       StartedMetadataBlock = true;
 899     }
 900     WriteValueAsMetadata(MDs[i], VE, Stream, Record);
 901   }
 902
 903   if (StartedMetadataBlock)
 904     Stream.ExitBlock();
 905 }
 906
 907 static void WriteMetadataAttachment(const Function &F,
 908                                     const ValueEnumerator &VE,
 909                                     BitstreamWriter &Stream) {
 910   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 911
 912   SmallVector<uint64_t, 64> Record;
 913
 914   // Write metadata attachments
 915   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 916   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
 917
 918   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 919     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 920          I != E; ++I) {
 921       MDs.clear();
 922       I->getAllMetadataOtherThanDebugLoc(MDs);
 923
 924       // If no metadata, ignore instruction.
 925       if (MDs.empty()) continue;
 926
 927       Record.push_back(VE.getInstructionID(I));
 928
 929       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 930         Record.push_back(MDs[i].first);
 931         Record.push_back(VE.getMetadataID(MDs[i].second));
 932       }
 933       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 934       Record.clear();
 935     }
 936
 937   Stream.ExitBlock();
 938 }
 939
 940 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 941   SmallVector<uint64_t, 64> Record;
 942
 943   // Write metadata kinds
 944   // METADATA_KIND - [n x [id, name]]
 945   SmallVector<StringRef, 8> Names;
 946   M->getMDKindNames(Names);
 947
 948   if (Names.empty()) return;
 949
 950   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 951
 952   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 953     Record.push_back(MDKindID);
 954     StringRef KName = Names[MDKindID];
 955     Record.append(KName.begin(), KName.end());
 956
 957     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 958     Record.clear();
 959   }
 960
 961   Stream.ExitBlock();
 962 }
 963
 964 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
 965   if ((int64_t)V >= 0)
 966     Vals.push_back(V << 1);
 967   else
 968     Vals.push_back((-V << 1) | 1);
 969 }
 970
 971 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 972                            const ValueEnumerator &VE,
 973                            BitstreamWriter &Stream, bool isGlobal) {
 974   if (FirstVal == LastVal) return;
 975
 976   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 977
 978   unsigned AggregateAbbrev = 0;
 979   unsigned String8Abbrev = 0;
 980   unsigned CString7Abbrev = 0;
 981   unsigned CString6Abbrev = 0;
 982   // If this is a constant pool for the module, emit module-specific abbrevs.
 983   if (isGlobal) {
 984     // Abbrev for CST_CODE_AGGREGATE.
 985     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 986     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 987     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 988     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 989     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 990
 991     // Abbrev for CST_CODE_STRING.
 992     Abbv = new BitCodeAbbrev();
 993     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 994     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 995     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 996     String8Abbrev = Stream.EmitAbbrev(Abbv);
 997     // Abbrev for CST_CODE_CSTRING.
 998     Abbv = new BitCodeAbbrev();
 999     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1000     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1001     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1002     CString7Abbrev = Stream.EmitAbbrev(Abbv);
1003     // Abbrev for CST_CODE_CSTRING.
1004     Abbv = new BitCodeAbbrev();
1005     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
1006     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1007     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1008     CString6Abbrev = Stream.EmitAbbrev(Abbv);
1009   }
1010
1011   SmallVector<uint64_t, 64> Record;
1012
1013   const ValueEnumerator::ValueList &Vals = VE.getValues();
1014   Type *LastTy = nullptr;
1015   for (unsigned i = FirstVal; i != LastVal; ++i) {
1016     const Value *V = Vals[i].first;
1017     // If we need to switch types, do so now.
1018     if (V->getType() != LastTy) {
1019       LastTy = V->getType();
1020       Record.push_back(VE.getTypeID(LastTy));
1021       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
1022                         CONSTANTS_SETTYPE_ABBREV);
1023       Record.clear();
1024     }
1025
1026     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
1027       Record.push_back(unsigned(IA->hasSideEffects()) |
1028                        unsigned(IA->isAlignStack()) << 1 |
1029                        unsigned(IA->getDialect()&1) << 2);
1030
1031       // Add the asm string.
1032       const std::string &AsmStr = IA->getAsmString();
1033       Record.push_back(AsmStr.size());
1034       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
1035         Record.push_back(AsmStr[i]);
1036
1037       // Add the constraint string.
1038       const std::string &ConstraintStr = IA->getConstraintString();
1039       Record.push_back(ConstraintStr.size());
1040       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
1041         Record.push_back(ConstraintStr[i]);
1042       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
1043       Record.clear();
1044       continue;
1045     }
1046     const Constant *C = cast<Constant>(V);
1047     unsigned Code = -1U;
1048     unsigned AbbrevToUse = 0;
1049     if (C->isNullValue()) {
1050       Code = bitc::CST_CODE_NULL;
1051     } else if (isa<UndefValue>(C)) {
1052       Code = bitc::CST_CODE_UNDEF;
1053     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
1054       if (IV->getBitWidth() <= 64) {
1055         uint64_t V = IV->getSExtValue();
1056         emitSignedInt64(Record, V);
1057         Code = bitc::CST_CODE_INTEGER;
1058         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
1059       } else {                             // Wide integers, > 64 bits in size.
1060         // We have an arbitrary precision integer value to write whose
1061         // bit width is > 64. However, in canonical unsigned integer
1062         // format it is likely that the high bits are going to be zero.
1063         // So, we only write the number of active words.
1064         unsigned NWords = IV->getValue().getActiveWords();
1065         const uint64_t *RawWords = IV->getValue().getRawData();
1066         for (unsigned i = 0; i != NWords; ++i) {
1067           emitSignedInt64(Record, RawWords[i]);
1068         }
1069         Code = bitc::CST_CODE_WIDE_INTEGER;
1070       }
1071     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1072       Code = bitc::CST_CODE_FLOAT;
1073       Type *Ty = CFP->getType();
1074       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
1075         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
1076       } else if (Ty->isX86_FP80Ty()) {
1077         // api needed to prevent premature destruction
1078         // bits are not in the same order as a normal i80 APInt, compensate.
1079         APInt api = CFP->getValueAPF().bitcastToAPInt();
1080         const uint64_t *p = api.getRawData();
1081         Record.push_back((p[1] << 48) | (p[0] >> 16));
1082         Record.push_back(p[0] & 0xffffLL);
1083       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
1084         APInt api = CFP->getValueAPF().bitcastToAPInt();
1085         const uint64_t *p = api.getRawData();
1086         Record.push_back(p[0]);
1087         Record.push_back(p[1]);
1088       } else {
1089         assert (0 && "Unknown FP type!");
1090       }
1091     } else if (isa<ConstantDataSequential>(C) &&
1092                cast<ConstantDataSequential>(C)->isString()) {
1093       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
1094       // Emit constant strings specially.
1095       unsigned NumElts = Str->getNumElements();
1096       // If this is a null-terminated string, use the denser CSTRING encoding.
1097       if (Str->isCString()) {
1098         Code = bitc::CST_CODE_CSTRING;
1099         --NumElts;  // Don't encode the null, which isn't allowed by char6.
1100       } else {
1101         Code = bitc::CST_CODE_STRING;
1102         AbbrevToUse = String8Abbrev;
1103       }
1104       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
1105       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
1106       for (unsigned i = 0; i != NumElts; ++i) {
1107         unsigned char V = Str->getElementAsInteger(i);
1108         Record.push_back(V);
1109         isCStr7 &= (V & 128) == 0;
1110         if (isCStrChar6)
1111           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
1112       }
1113
1114       if (isCStrChar6)
1115         AbbrevToUse = CString6Abbrev;
1116       else if (isCStr7)
1117         AbbrevToUse = CString7Abbrev;
1118     } else if (const ConstantDataSequential *CDS =
1119                   dyn_cast<ConstantDataSequential>(C)) {
1120       Code = bitc::CST_CODE_DATA;
1121       Type *EltTy = CDS->getType()->getElementType();
1122       if (isa<IntegerType>(EltTy)) {
1123         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
1124           Record.push_back(CDS->getElementAsInteger(i));
1125       } else if (EltTy->isFloatTy()) {
1126         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1127           union { float F; uint32_t I; };
1128           F = CDS->getElementAsFloat(i);
1129           Record.push_back(I);
1130         }
1131       } else {
1132         assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
1133         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1134           union { double F; uint64_t I; };
1135           F = CDS->getElementAsDouble(i);
1136           Record.push_back(I);
1137         }
1138       }
1139     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
1140                isa<ConstantVector>(C)) {
1141       Code = bitc::CST_CODE_AGGREGATE;
1142       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
1143         Record.push_back(VE.getValueID(C->getOperand(i)));
1144       AbbrevToUse = AggregateAbbrev;
1145     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1146       switch (CE->getOpcode()) {
1147       default:
1148         if (Instruction::isCast(CE->getOpcode())) {
1149           Code = bitc::CST_CODE_CE_CAST;
1150           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
1151           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1152           Record.push_back(VE.getValueID(C->getOperand(0)));
1153           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
1154         } else {
1155           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
1156           Code = bitc::CST_CODE_CE_BINOP;
1157           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
1158           Record.push_back(VE.getValueID(C->getOperand(0)));
1159           Record.push_back(VE.getValueID(C->getOperand(1)));
1160           uint64_t Flags = GetOptimizationFlags(CE);
1161           if (Flags != 0)
1162             Record.push_back(Flags);
1163         }
1164         break;
1165       case Instruction::GetElementPtr:
1166         Code = bitc::CST_CODE_CE_GEP;
1167         if (cast<GEPOperator>(C)->isInBounds())
1168           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
1169         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
1170           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
1171           Record.push_back(VE.getValueID(C->getOperand(i)));
1172         }
1173         break;
1174       case Instruction::Select:
1175         Code = bitc::CST_CODE_CE_SELECT;
1176         Record.push_back(VE.getValueID(C->getOperand(0)));
1177         Record.push_back(VE.getValueID(C->getOperand(1)));
1178         Record.push_back(VE.getValueID(C->getOperand(2)));
1179         break;
1180       case Instruction::ExtractElement:
1181         Code = bitc::CST_CODE_CE_EXTRACTELT;
1182         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1183         Record.push_back(VE.getValueID(C->getOperand(0)));
1184         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
1185         Record.push_back(VE.getValueID(C->getOperand(1)));
1186         break;
1187       case Instruction::InsertElement:
1188         Code = bitc::CST_CODE_CE_INSERTELT;
1189         Record.push_back(VE.getValueID(C->getOperand(0)));
1190         Record.push_back(VE.getValueID(C->getOperand(1)));
1191         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
1192         Record.push_back(VE.getValueID(C->getOperand(2)));
1193         break;
1194       case Instruction::ShuffleVector:
1195         // If the return type and argument types are the same, this is a
1196         // standard shufflevector instruction.  If the types are different,
1197         // then the shuffle is widening or truncating the input vectors, and
1198         // the argument type must also be encoded.
1199         if (C->getType() == C->getOperand(0)->getType()) {
1200           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
1201         } else {
1202           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
1203           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1204         }
1205         Record.push_back(VE.getValueID(C->getOperand(0)));
1206         Record.push_back(VE.getValueID(C->getOperand(1)));
1207         Record.push_back(VE.getValueID(C->getOperand(2)));
1208         break;
1209       case Instruction::ICmp:
1210       case Instruction::FCmp:
1211         Code = bitc::CST_CODE_CE_CMP;
1212         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
1213         Record.push_back(VE.getValueID(C->getOperand(0)));
1214         Record.push_back(VE.getValueID(C->getOperand(1)));
1215         Record.push_back(CE->getPredicate());
1216         break;
1217       }
1218     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
1219       Code = bitc::CST_CODE_BLOCKADDRESS;
1220       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
1221       Record.push_back(VE.getValueID(BA->getFunction()));
1222       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
1223     } else {
1224 #ifndef NDEBUG
1225       C->dump();
1226 #endif
1227       llvm_unreachable("Unknown constant!");
1228     }
1229     Stream.EmitRecord(Code, Record, AbbrevToUse);
1230     Record.clear();
1231   }
1232
1233   Stream.ExitBlock();
1234 }
1235
1236 static void WriteModuleConstants(const ValueEnumerator &VE,
1237                                  BitstreamWriter &Stream) {
1238   const ValueEnumerator::ValueList &Vals = VE.getValues();
1239
1240   // Find the first constant to emit, which is the first non-globalvalue value.
1241   // We know globalvalues have been emitted by WriteModuleInfo.
1242   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
1243     if (!isa<GlobalValue>(Vals[i].first)) {
1244       WriteConstants(i, Vals.size(), VE, Stream, true);
1245       return;
1246     }
1247   }
1248 }
1249
1250 /// PushValueAndType - The file has to encode both the value and type id for
1251 /// many values, because we need to know what type to create for forward
1252 /// references.  However, most operands are not forward references, so this type
1253 /// field is not needed.
1254 ///
1255 /// This function adds V's value ID to Vals.  If the value ID is higher than the
1256 /// instruction ID, then it is a forward reference, and it also includes the
1257 /// type ID.  The value ID that is written is encoded relative to the InstID.
1258 static bool PushValueAndType(const Value *V, unsigned InstID,
1259                              SmallVectorImpl<unsigned> &Vals,
1260                              ValueEnumerator &VE) {
1261   unsigned ValID = VE.getValueID(V);
1262   // Make encoding relative to the InstID.
1263   Vals.push_back(InstID - ValID);
1264   if (ValID >= InstID) {
1265     Vals.push_back(VE.getTypeID(V->getType()));
1266     return true;
1267   }
1268   return false;
1269 }
1270
1271 /// pushValue - Like PushValueAndType, but where the type of the value is
1272 /// omitted (perhaps it was already encoded in an earlier operand).
1273 static void pushValue(const Value *V, unsigned InstID,
1274                       SmallVectorImpl<unsigned> &Vals,
1275                       ValueEnumerator &VE) {
1276   unsigned ValID = VE.getValueID(V);
1277   Vals.push_back(InstID - ValID);
1278 }
1279
1280 static void pushValueSigned(const Value *V, unsigned InstID,
1281                             SmallVectorImpl<uint64_t> &Vals,
1282                             ValueEnumerator &VE) {
1283   unsigned ValID = VE.getValueID(V);
1284   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
1285   emitSignedInt64(Vals, diff);
1286 }
1287
1288 /// WriteInstruction - Emit an instruction to the specified stream.
1289 static void WriteInstruction(const Instruction &I, unsigned InstID,
1290                              ValueEnumerator &VE, BitstreamWriter &Stream,
1291                              SmallVectorImpl<unsigned> &Vals) {
1292   unsigned Code = 0;
1293   unsigned AbbrevToUse = 0;
1294   VE.setInstructionID(&I);
1295   switch (I.getOpcode()) {
1296   default:
1297     if (Instruction::isCast(I.getOpcode())) {
1298       Code = bitc::FUNC_CODE_INST_CAST;
1299       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1300         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1301       Vals.push_back(VE.getTypeID(I.getType()));
1302       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1303     } else {
1304       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1305       Code = bitc::FUNC_CODE_INST_BINOP;
1306       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1307         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1308       pushValue(I.getOperand(1), InstID, Vals, VE);
1309       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1310       uint64_t Flags = GetOptimizationFlags(&I);
1311       if (Flags != 0) {
1312         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1313           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1314         Vals.push_back(Flags);
1315       }
1316     }
1317     break;
1318
1319   case Instruction::GetElementPtr:
1320     Code = bitc::FUNC_CODE_INST_GEP;
1321     if (cast<GEPOperator>(&I)->isInBounds())
1322       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1323     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1324       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1325     break;
1326   case Instruction::ExtractValue: {
1327     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1328     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1329     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1330     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1331       Vals.push_back(*i);
1332     break;
1333   }
1334   case Instruction::InsertValue: {
1335     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1336     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1337     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1338     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1339     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1340       Vals.push_back(*i);
1341     break;
1342   }
1343   case Instruction::Select:
1344     Code = bitc::FUNC_CODE_INST_VSELECT;
1345     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1346     pushValue(I.getOperand(2), InstID, Vals, VE);
1347     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1348     break;
1349   case Instruction::ExtractElement:
1350     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1351     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1352     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1353     break;
1354   case Instruction::InsertElement:
1355     Code = bitc::FUNC_CODE_INST_INSERTELT;
1356     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1357     pushValue(I.getOperand(1), InstID, Vals, VE);
1358     PushValueAndType(I.getOperand(2), InstID, Vals, VE);
1359     break;
1360   case Instruction::ShuffleVector:
1361     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1362     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1363     pushValue(I.getOperand(1), InstID, Vals, VE);
1364     pushValue(I.getOperand(2), InstID, Vals, VE);
1365     break;
1366   case Instruction::ICmp:
1367   case Instruction::FCmp:
1368     // compare returning Int1Ty or vector of Int1Ty
1369     Code = bitc::FUNC_CODE_INST_CMP2;
1370     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1371     pushValue(I.getOperand(1), InstID, Vals, VE);
1372     Vals.push_back(cast<CmpInst>(I).getPredicate());
1373     break;
1374
1375   case Instruction::Ret:
1376     {
1377       Code = bitc::FUNC_CODE_INST_RET;
1378       unsigned NumOperands = I.getNumOperands();
1379       if (NumOperands == 0)
1380         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1381       else if (NumOperands == 1) {
1382         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1383           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1384       } else {
1385         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1386           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1387       }
1388     }
1389     break;
1390   case Instruction::Br:
1391     {
1392       Code = bitc::FUNC_CODE_INST_BR;
1393       const BranchInst &II = cast<BranchInst>(I);
1394       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1395       if (II.isConditional()) {
1396         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1397         pushValue(II.getCondition(), InstID, Vals, VE);
1398       }
1399     }
1400     break;
1401   case Instruction::Switch:
1402     {
1403       Code = bitc::FUNC_CODE_INST_SWITCH;
1404       const SwitchInst &SI = cast<SwitchInst>(I);
1405       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
1406       pushValue(SI.getCondition(), InstID, Vals, VE);
1407       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
1408       for (SwitchInst::ConstCaseIt i = SI.case_begin(), e = SI.case_end();
1409            i != e; ++i) {
1410         Vals.push_back(VE.getValueID(i.getCaseValue()));
1411         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
1412       }
1413     }
1414     break;
1415   case Instruction::IndirectBr:
1416     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1417     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1418     // Encode the address operand as relative, but not the basic blocks.
1419     pushValue(I.getOperand(0), InstID, Vals, VE);
1420     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
1421       Vals.push_back(VE.getValueID(I.getOperand(i)));
1422     break;
1423
1424   case Instruction::Invoke: {
1425     const InvokeInst *II = cast<InvokeInst>(&I);
1426     const Value *Callee(II->getCalledValue());
1427     PointerType *PTy = cast<PointerType>(Callee->getType());
1428     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1429     Code = bitc::FUNC_CODE_INST_INVOKE;
1430
1431     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1432     Vals.push_back(II->getCallingConv());
1433     Vals.push_back(VE.getValueID(II->getNormalDest()));
1434     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1435     PushValueAndType(Callee, InstID, Vals, VE);
1436
1437     // Emit value #'s for the fixed parameters.
1438     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1439       pushValue(I.getOperand(i), InstID, Vals, VE);  // fixed param.
1440
1441     // Emit type/value pairs for varargs params.
1442     if (FTy->isVarArg()) {
1443       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1444            i != e; ++i)
1445         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1446     }
1447     break;
1448   }
1449   case Instruction::Resume:
1450     Code = bitc::FUNC_CODE_INST_RESUME;
1451     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1452     break;
1453   case Instruction::Unreachable:
1454     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1455     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1456     break;
1457
1458   case Instruction::PHI: {
1459     const PHINode &PN = cast<PHINode>(I);
1460     Code = bitc::FUNC_CODE_INST_PHI;
1461     // With the newer instruction encoding, forward references could give
1462     // negative valued IDs.  This is most common for PHIs, so we use
1463     // signed VBRs.
1464     SmallVector<uint64_t, 128> Vals64;
1465     Vals64.push_back(VE.getTypeID(PN.getType()));
1466     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1467       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64, VE);
1468       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1469     }
1470     // Emit a Vals64 vector and exit.
1471     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
1472     Vals64.clear();
1473     return;
1474   }
1475
1476   case Instruction::LandingPad: {
1477     const LandingPadInst &LP = cast<LandingPadInst>(I);
1478     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1479     Vals.push_back(VE.getTypeID(LP.getType()));
1480     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1481     Vals.push_back(LP.isCleanup());
1482     Vals.push_back(LP.getNumClauses());
1483     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1484       if (LP.isCatch(I))
1485         Vals.push_back(LandingPadInst::Catch);
1486       else
1487         Vals.push_back(LandingPadInst::Filter);
1488       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1489     }
1490     break;
1491   }
1492
1493   case Instruction::Alloca: {
1494     Code = bitc::FUNC_CODE_INST_ALLOCA;
1495     Vals.push_back(VE.getTypeID(I.getType()));
1496     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1497     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1498     const AllocaInst &AI = cast<AllocaInst>(I);
1499     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
1500     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
1501            "not enough bits for maximum alignment");
1502     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
1503     AlignRecord |= AI.isUsedWithInAlloca() << 5;
1504     Vals.push_back(AlignRecord);
1505     break;
1506   }
1507
1508   case Instruction::Load:
1509     if (cast<LoadInst>(I).isAtomic()) {
1510       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1511       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1512     } else {
1513       Code = bitc::FUNC_CODE_INST_LOAD;
1514       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1515         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1516     }
1517     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1518     Vals.push_back(cast<LoadInst>(I).isVolatile());
1519     if (cast<LoadInst>(I).isAtomic()) {
1520       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1521       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1522     }
1523     break;
1524   case Instruction::Store:
1525     if (cast<StoreInst>(I).isAtomic())
1526       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1527     else
1528       Code = bitc::FUNC_CODE_INST_STORE;
1529     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1530     pushValue(I.getOperand(0), InstID, Vals, VE);         // val.
1531     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1532     Vals.push_back(cast<StoreInst>(I).isVolatile());
1533     if (cast<StoreInst>(I).isAtomic()) {
1534       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1535       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1536     }
1537     break;
1538   case Instruction::AtomicCmpXchg:
1539     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1540     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1541     pushValue(I.getOperand(1), InstID, Vals, VE);         // cmp.
1542     pushValue(I.getOperand(2), InstID, Vals, VE);         // newval.
1543     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1544     Vals.push_back(GetEncodedOrdering(
1545                      cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
1546     Vals.push_back(GetEncodedSynchScope(
1547                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1548     Vals.push_back(GetEncodedOrdering(
1549                      cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
1550     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
1551     break;
1552   case Instruction::AtomicRMW:
1553     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1554     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1555     pushValue(I.getOperand(1), InstID, Vals, VE);         // val.
1556     Vals.push_back(GetEncodedRMWOperation(
1557                      cast<AtomicRMWInst>(I).getOperation()));
1558     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1559     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1560     Vals.push_back(GetEncodedSynchScope(
1561                      cast<AtomicRMWInst>(I).getSynchScope()));
1562     break;
1563   case Instruction::Fence:
1564     Code = bitc::FUNC_CODE_INST_FENCE;
1565     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1566     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1567     break;
1568   case Instruction::Call: {
1569     const CallInst &CI = cast<CallInst>(I);
1570     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1571     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1572
1573     Code = bitc::FUNC_CODE_INST_CALL;
1574
1575     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1576     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
1577                    unsigned(CI.isMustTailCall()) << 14);
1578     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1579
1580     // Emit value #'s for the fixed parameters.
1581     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
1582       // Check for labels (can happen with asm labels).
1583       if (FTy->getParamType(i)->isLabelTy())
1584         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
1585       else
1586         pushValue(CI.getArgOperand(i), InstID, Vals, VE);  // fixed param.
1587     }
1588
1589     // Emit type/value pairs for varargs params.
1590     if (FTy->isVarArg()) {
1591       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1592            i != e; ++i)
1593         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1594     }
1595     break;
1596   }
1597   case Instruction::VAArg:
1598     Code = bitc::FUNC_CODE_INST_VAARG;
1599     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1600     pushValue(I.getOperand(0), InstID, Vals, VE); // valist.
1601     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1602     break;
1603   }
1604
1605   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1606   Vals.clear();
1607 }
1608
1609 // Emit names for globals/functions etc.
1610 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1611                                   const ValueEnumerator &VE,
1612                                   BitstreamWriter &Stream) {
1613   if (VST.empty()) return;
1614   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1615
1616   // FIXME: Set up the abbrev, we know how many values there are!
1617   // FIXME: We know if the type names can use 7-bit ascii.
1618   SmallVector<unsigned, 64> NameVals;
1619
1620   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1621        SI != SE; ++SI) {
1622
1623     const ValueName &Name = *SI;
1624
1625     // Figure out the encoding to use for the name.
1626     bool is7Bit = true;
1627     bool isChar6 = true;
1628     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1629          C != E; ++C) {
1630       if (isChar6)
1631         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1632       if ((unsigned char)*C & 128) {
1633         is7Bit = false;
1634         break;  // don't bother scanning the rest.
1635       }
1636     }
1637
1638     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1639
1640     // VST_ENTRY:   [valueid, namechar x N]
1641     // VST_BBENTRY: [bbid, namechar x N]
1642     unsigned Code;
1643     if (isa<BasicBlock>(SI->getValue())) {
1644       Code = bitc::VST_CODE_BBENTRY;
1645       if (isChar6)
1646         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1647     } else {
1648       Code = bitc::VST_CODE_ENTRY;
1649       if (isChar6)
1650         AbbrevToUse = VST_ENTRY_6_ABBREV;
1651       else if (is7Bit)
1652         AbbrevToUse = VST_ENTRY_7_ABBREV;
1653     }
1654
1655     NameVals.push_back(VE.getValueID(SI->getValue()));
1656     for (const char *P = Name.getKeyData(),
1657          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1658       NameVals.push_back((unsigned char)*P);
1659
1660     // Emit the finished record.
1661     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1662     NameVals.clear();
1663   }
1664   Stream.ExitBlock();
1665 }
1666
1667 static void WriteUseList(ValueEnumerator &VE, UseListOrder &&Order,
1668                          BitstreamWriter &Stream) {
1669   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
1670   unsigned Code;
1671   if (isa<BasicBlock>(Order.V))
1672     Code = bitc::USELIST_CODE_BB;
1673   else
1674     Code = bitc::USELIST_CODE_DEFAULT;
1675
1676   SmallVector<uint64_t, 64> Record;
1677   for (unsigned I : Order.Shuffle)
1678     Record.push_back(I);
1679   Record.push_back(VE.getValueID(Order.V));
1680   Stream.EmitRecord(Code, Record);
1681 }
1682
1683 static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
1684                               BitstreamWriter &Stream) {
1685   auto hasMore = [&]() {
1686     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
1687   };
1688   if (!hasMore())
1689     // Nothing to do.
1690     return;
1691
1692   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1693   while (hasMore()) {
1694     WriteUseList(VE, std::move(VE.UseListOrders.back()), Stream);
1695     VE.UseListOrders.pop_back();
1696   }
1697   Stream.ExitBlock();
1698 }
1699
1700 /// WriteFunction - Emit a function body to the module stream.
1701 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1702                           BitstreamWriter &Stream) {
1703   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1704   VE.incorporateFunction(F);
1705
1706   SmallVector<unsigned, 64> Vals;
1707
1708   // Emit the number of basic blocks, so the reader can create them ahead of
1709   // time.
1710   Vals.push_back(VE.getBasicBlocks().size());
1711   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1712   Vals.clear();
1713
1714   // If there are function-local constants, emit them now.
1715   unsigned CstStart, CstEnd;
1716   VE.getFunctionConstantRange(CstStart, CstEnd);
1717   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1718
1719   // If there is function-local metadata, emit it now.
1720   WriteFunctionLocalMetadata(F, VE, Stream);
1721
1722   // Keep a running idea of what the instruction ID is.
1723   unsigned InstID = CstEnd;
1724
1725   bool NeedsMetadataAttachment = false;
1726
1727   DebugLoc LastDL;
1728
1729   // Finally, emit all the instructions, in order.
1730   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1731     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1732          I != E; ++I) {
1733       WriteInstruction(*I, InstID, VE, Stream, Vals);
1734
1735       if (!I->getType()->isVoidTy())
1736         ++InstID;
1737
1738       // If the instruction has metadata, write a metadata attachment later.
1739       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1740
1741       // If the instruction has a debug location, emit it.
1742       DebugLoc DL = I->getDebugLoc();
1743       if (DL.isUnknown()) {
1744         // nothing todo.
1745       } else if (DL == LastDL) {
1746         // Just repeat the same debug loc as last time.
1747         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1748       } else {
1749         MDNode *Scope, *IA;
1750         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1751         assert(Scope && "Expected valid scope");
1752
1753         Vals.push_back(DL.getLine());
1754         Vals.push_back(DL.getCol());
1755         Vals.push_back(Scope ? VE.getMetadataID(Scope) + 1 : 0);
1756         Vals.push_back(IA ? VE.getMetadataID(IA) + 1 : 0);
1757         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1758         Vals.clear();
1759
1760         LastDL = DL;
1761       }
1762     }
1763
1764   // Emit names for all the instructions etc.
1765   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1766
1767   if (NeedsMetadataAttachment)
1768     WriteMetadataAttachment(F, VE, Stream);
1769   if (shouldPreserveBitcodeUseListOrder())
1770     WriteUseListBlock(&F, VE, Stream);
1771   VE.purgeFunction();
1772   Stream.ExitBlock();
1773 }
1774
1775 // Emit blockinfo, which defines the standard abbreviations etc.
1776 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1777   // We only want to emit block info records for blocks that have multiple
1778   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
1779   // Other blocks can define their abbrevs inline.
1780   Stream.EnterBlockInfoBlock(2);
1781
1782   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1783     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1787     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1788     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1789                                    Abbv) != VST_ENTRY_8_ABBREV)
1790       llvm_unreachable("Unexpected abbrev ordering!");
1791   }
1792
1793   { // 7-bit fixed width VST_ENTRY strings.
1794     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1795     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1799     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1800                                    Abbv) != VST_ENTRY_7_ABBREV)
1801       llvm_unreachable("Unexpected abbrev ordering!");
1802   }
1803   { // 6-bit char6 VST_ENTRY strings.
1804     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1805     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1807     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1808     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1809     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1810                                    Abbv) != VST_ENTRY_6_ABBREV)
1811       llvm_unreachable("Unexpected abbrev ordering!");
1812   }
1813   { // 6-bit char6 VST_BBENTRY strings.
1814     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1815     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1817     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1818     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1819     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1820                                    Abbv) != VST_BBENTRY_6_ABBREV)
1821       llvm_unreachable("Unexpected abbrev ordering!");
1822   }
1823
1824
1825
1826   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1827     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1828     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1829     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1830                               Log2_32_Ceil(VE.getTypes().size()+1)));
1831     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1832                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1833       llvm_unreachable("Unexpected abbrev ordering!");
1834   }
1835
1836   { // INTEGER abbrev for CONSTANTS_BLOCK.
1837     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1838     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1839     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1840     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1841                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1842       llvm_unreachable("Unexpected abbrev ordering!");
1843   }
1844
1845   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1846     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1847     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1848     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1849     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1850                               Log2_32_Ceil(VE.getTypes().size()+1)));
1851     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1852
1853     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1854                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1855       llvm_unreachable("Unexpected abbrev ordering!");
1856   }
1857   { // NULL abbrev for CONSTANTS_BLOCK.
1858     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1859     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1860     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1861                                    Abbv) != CONSTANTS_NULL_Abbrev)
1862       llvm_unreachable("Unexpected abbrev ordering!");
1863   }
1864
1865   // FIXME: This should only use space for first class types!
1866
1867   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1868     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1869     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1870     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1871     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1873     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1874                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1875       llvm_unreachable("Unexpected abbrev ordering!");
1876   }
1877   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1878     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1879     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1880     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1881     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1883     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1884                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1885       llvm_unreachable("Unexpected abbrev ordering!");
1886   }
1887   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1888     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1889     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1890     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1891     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1892     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1894     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1895                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1896       llvm_unreachable("Unexpected abbrev ordering!");
1897   }
1898   { // INST_CAST abbrev for FUNCTION_BLOCK.
1899     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1900     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1901     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1902     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1903                               Log2_32_Ceil(VE.getTypes().size()+1)));
1904     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1905     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1906                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1907       llvm_unreachable("Unexpected abbrev ordering!");
1908   }
1909
1910   { // INST_RET abbrev for FUNCTION_BLOCK.
1911     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1912     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1913     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1914                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1915       llvm_unreachable("Unexpected abbrev ordering!");
1916   }
1917   { // INST_RET abbrev for FUNCTION_BLOCK.
1918     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1919     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1920     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1921     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1922                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1923       llvm_unreachable("Unexpected abbrev ordering!");
1924   }
1925   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1926     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1927     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1928     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1929                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1930       llvm_unreachable("Unexpected abbrev ordering!");
1931   }
1932
1933   Stream.ExitBlock();
1934 }
1935
1936 /// WriteModule - Emit the specified module to the bitstream.
1937 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1938   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1939
1940   SmallVector<unsigned, 1> Vals;
1941   unsigned CurVersion = 1;
1942   Vals.push_back(CurVersion);
1943   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1944
1945   // Analyze the module, enumerating globals, functions, etc.
1946   ValueEnumerator VE(*M);
1947
1948   // Emit blockinfo, which defines the standard abbreviations etc.
1949   WriteBlockInfo(VE, Stream);
1950
1951   // Emit information about attribute groups.
1952   WriteAttributeGroupTable(VE, Stream);
1953
1954   // Emit information about parameter attributes.
1955   WriteAttributeTable(VE, Stream);
1956
1957   // Emit information describing all of the types in the module.
1958   WriteTypeTable(VE, Stream);
1959
1960   writeComdats(VE, Stream);
1961
1962   // Emit top-level description of module, including target triple, inline asm,
1963   // descriptors for global variables, and function prototype info.
1964   WriteModuleInfo(M, VE, Stream);
1965
1966   // Emit constants.
1967   WriteModuleConstants(VE, Stream);
1968
1969   // Emit metadata.
1970   WriteModuleMetadata(M, VE, Stream);
1971
1972   // Emit metadata.
1973   WriteModuleMetadataStore(M, Stream);
1974
1975   // Emit names for globals/functions etc.
1976   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1977
1978   // Emit module-level use-lists.
1979   if (shouldPreserveBitcodeUseListOrder())
1980     WriteUseListBlock(nullptr, VE, Stream);
1981
1982   // Emit function bodies.
1983   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1984     if (!F->isDeclaration())
1985       WriteFunction(*F, VE, Stream);
1986
1987   Stream.ExitBlock();
1988 }
1989
1990 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1991 /// header and trailer to make it compatible with the system archiver.  To do
1992 /// this we emit the following header, and then emit a trailer that pads the
1993 /// file out to be a multiple of 16 bytes.
1994 ///
1995 /// struct bc_header {
1996 ///   uint32_t Magic;         // 0x0B17C0DE
1997 ///   uint32_t Version;       // Version, currently always 0.
1998 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1999 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
2000 ///   uint32_t CPUType;       // CPU specifier.
2001 ///   ... potentially more later ...
2002 /// };
2003 enum {
2004   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
2005   DarwinBCHeaderSize = 5*4
2006 };
2007
2008 static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
2009                                uint32_t &Position) {
2010   Buffer[Position + 0] = (unsigned char) (Value >>  0);
2011   Buffer[Position + 1] = (unsigned char) (Value >>  8);
2012   Buffer[Position + 2] = (unsigned char) (Value >> 16);
2013   Buffer[Position + 3] = (unsigned char) (Value >> 24);
2014   Position += 4;
2015 }
2016
2017 static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
2018                                          const Triple &TT) {
2019   unsigned CPUType = ~0U;
2020
2021   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
2022   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
2023   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
2024   // specific constants here because they are implicitly part of the Darwin ABI.
2025   enum {
2026     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
2027     DARWIN_CPU_TYPE_X86        = 7,
2028     DARWIN_CPU_TYPE_ARM        = 12,
2029     DARWIN_CPU_TYPE_POWERPC    = 18
2030   };
2031
2032   Triple::ArchType Arch = TT.getArch();
2033   if (Arch == Triple::x86_64)
2034     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
2035   else if (Arch == Triple::x86)
2036     CPUType = DARWIN_CPU_TYPE_X86;
2037   else if (Arch == Triple::ppc)
2038     CPUType = DARWIN_CPU_TYPE_POWERPC;
2039   else if (Arch == Triple::ppc64)
2040     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
2041   else if (Arch == Triple::arm || Arch == Triple::thumb)
2042     CPUType = DARWIN_CPU_TYPE_ARM;
2043
2044   // Traditional Bitcode starts after header.
2045   assert(Buffer.size() >= DarwinBCHeaderSize &&
2046          "Expected header size to be reserved");
2047   unsigned BCOffset = DarwinBCHeaderSize;
2048   unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
2049
2050   // Write the magic and version.
2051   unsigned Position = 0;
2052   WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
2053   WriteInt32ToBuffer(0          , Buffer, Position); // Version.
2054   WriteInt32ToBuffer(BCOffset   , Buffer, Position);
2055   WriteInt32ToBuffer(BCSize     , Buffer, Position);
2056   WriteInt32ToBuffer(CPUType    , Buffer, Position);
2057
2058   // If the file is not a multiple of 16 bytes, insert dummy padding.
2059   while (Buffer.size() & 15)
2060     Buffer.push_back(0);
2061 }
2062
2063 /// WriteBitcodeToFile - Write the specified module to the specified output
2064 /// stream.
2065 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
2066   SmallVector<char, 0> Buffer;
2067   Buffer.reserve(256*1024);
2068
2069   // If this is darwin or another generic macho target, reserve space for the
2070   // header.
2071   Triple TT(M->getTargetTriple());
2072   if (TT.isOSDarwin())
2073     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
2074
2075   // Emit the module into the buffer.
2076   {
2077     BitstreamWriter Stream(Buffer);
2078
2079     // Emit the file header.
2080     Stream.Emit((unsigned)'B', 8);
2081     Stream.Emit((unsigned)'C', 8);
2082     Stream.Emit(0x0, 4);
2083     Stream.Emit(0xC, 4);
2084     Stream.Emit(0xE, 4);
2085     Stream.Emit(0xD, 4);
2086
2087     // Emit the module.
2088     WriteModule(M, Stream);
2089   }
2090
2091   if (TT.isOSDarwin())
2092     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
2093
2094   // Write the generated bitstream to "Out".
2095   Out.write((char*)&Buffer.front(), Buffer.size());
2096 }