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