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 "llvm/Bitcode/BitstreamWriter.h"
  16 #include "llvm/Bitcode/LLVMBitCodes.h"
  17 #include "ValueEnumerator.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/DerivedTypes.h"
  20 #include "llvm/InlineAsm.h"
  21 #include "llvm/Instructions.h"
  22 #include "llvm/Module.h"
  23 #include "llvm/Operator.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/ADT/Triple.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/MathExtras.h"
  29 #include "llvm/Support/raw_ostream.h"
  30 #include "llvm/Support/Program.h"
  31 #include <cctype>
  32 #include <map>
  33 using namespace llvm;
  34
  35 static cl::opt<bool>
  36 EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
  37                               cl::desc("Turn on experimental support for "
  38                                        "use-list order preservation."),
  39                               cl::init(false), cl::Hidden);
  40
  41 /// These are manifest constants used by the bitcode writer. They do not need to
  42 /// be kept in sync with the reader, but need to be consistent within this file.
  43 enum {
  44   CurVersion = 0,
  45
  46   // VALUE_SYMTAB_BLOCK abbrev id's.
  47   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  48   VST_ENTRY_7_ABBREV,
  49   VST_ENTRY_6_ABBREV,
  50   VST_BBENTRY_6_ABBREV,
  51
  52   // CONSTANTS_BLOCK abbrev id's.
  53   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  54   CONSTANTS_INTEGER_ABBREV,
  55   CONSTANTS_CE_CAST_Abbrev,
  56   CONSTANTS_NULL_Abbrev,
  57
  58   // FUNCTION_BLOCK abbrev id's.
  59   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  60   FUNCTION_INST_BINOP_ABBREV,
  61   FUNCTION_INST_BINOP_FLAGS_ABBREV,
  62   FUNCTION_INST_CAST_ABBREV,
  63   FUNCTION_INST_RET_VOID_ABBREV,
  64   FUNCTION_INST_RET_VAL_ABBREV,
  65   FUNCTION_INST_UNREACHABLE_ABBREV
  66 };
  67
  68 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  69   switch (Opcode) {
  70   default: llvm_unreachable("Unknown cast instruction!");
  71   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  72   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  73   case Instruction::SExt    : return bitc::CAST_SEXT;
  74   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  75   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  76   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  77   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  78   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  79   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  80   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  81   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  82   case Instruction::BitCast : return bitc::CAST_BITCAST;
  83   }
  84 }
  85
  86 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  87   switch (Opcode) {
  88   default: llvm_unreachable("Unknown binary instruction!");
  89   case Instruction::Add:
  90   case Instruction::FAdd: return bitc::BINOP_ADD;
  91   case Instruction::Sub:
  92   case Instruction::FSub: return bitc::BINOP_SUB;
  93   case Instruction::Mul:
  94   case Instruction::FMul: return bitc::BINOP_MUL;
  95   case Instruction::UDiv: return bitc::BINOP_UDIV;
  96   case Instruction::FDiv:
  97   case Instruction::SDiv: return bitc::BINOP_SDIV;
  98   case Instruction::URem: return bitc::BINOP_UREM;
  99   case Instruction::FRem:
 100   case Instruction::SRem: return bitc::BINOP_SREM;
 101   case Instruction::Shl:  return bitc::BINOP_SHL;
 102   case Instruction::LShr: return bitc::BINOP_LSHR;
 103   case Instruction::AShr: return bitc::BINOP_ASHR;
 104   case Instruction::And:  return bitc::BINOP_AND;
 105   case Instruction::Or:   return bitc::BINOP_OR;
 106   case Instruction::Xor:  return bitc::BINOP_XOR;
 107   }
 108 }
 109
 110 static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 111   switch (Op) {
 112   default: llvm_unreachable("Unknown RMW operation!");
 113   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
 114   case AtomicRMWInst::Add: return bitc::RMW_ADD;
 115   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
 116   case AtomicRMWInst::And: return bitc::RMW_AND;
 117   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
 118   case AtomicRMWInst::Or: return bitc::RMW_OR;
 119   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
 120   case AtomicRMWInst::Max: return bitc::RMW_MAX;
 121   case AtomicRMWInst::Min: return bitc::RMW_MIN;
 122   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
 123   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
 124   }
 125 }
 126
 127 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
 128   switch (Ordering) {
 129   default: llvm_unreachable("Unknown atomic ordering");
 130   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
 131   case Unordered: return bitc::ORDERING_UNORDERED;
 132   case Monotonic: return bitc::ORDERING_MONOTONIC;
 133   case Acquire: return bitc::ORDERING_ACQUIRE;
 134   case Release: return bitc::ORDERING_RELEASE;
 135   case AcquireRelease: return bitc::ORDERING_ACQREL;
 136   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
 137   }
 138 }
 139
 140 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
 141   switch (SynchScope) {
 142   default: llvm_unreachable("Unknown synchronization scope");
 143   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
 144   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
 145   }
 146 }
 147
 148 static void WriteStringRecord(unsigned Code, StringRef Str,
 149                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 150   SmallVector<unsigned, 64> Vals;
 151
 152   // Code: [strchar x N]
 153   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
 154     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
 155       AbbrevToUse = 0;
 156     Vals.push_back(Str[i]);
 157   }
 158
 159   // Emit the finished record.
 160   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 161 }
 162
 163 // Emit information about parameter attributes.
 164 static void WriteAttributeTable(const ValueEnumerator &VE,
 165                                 BitstreamWriter &Stream) {
 166   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 167   if (Attrs.empty()) return;
 168
 169   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 170
 171   SmallVector<uint64_t, 64> Record;
 172   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 173     const AttrListPtr &A = Attrs[i];
 174     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 175       const AttributeWithIndex &PAWI = A.getSlot(i);
 176       Record.push_back(PAWI.Index);
 177
 178       // FIXME: remove in LLVM 3.0
 179       // Store the alignment in the bitcode as a 16-bit raw value instead of a
 180       // 5-bit log2 encoded value. Shift the bits above the alignment up by
 181       // 11 bits.
 182       uint64_t FauxAttr = PAWI.Attrs & 0xffff;
 183       if (PAWI.Attrs & Attribute::Alignment)
 184         FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
 185       FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
 186
 187       Record.push_back(FauxAttr);
 188     }
 189
 190     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 191     Record.clear();
 192   }
 193
 194   Stream.ExitBlock();
 195 }
 196
 197 /// WriteTypeTable - Write out the type table for a module.
 198 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 199   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 200
 201   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
 202   SmallVector<uint64_t, 64> TypeVals;
 203
 204   // Abbrev for TYPE_CODE_POINTER.
 205   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 206   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 208                             Log2_32_Ceil(VE.getTypes().size()+1)));
 209   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 210   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 211
 212   // Abbrev for TYPE_CODE_FUNCTION.
 213   Abbv = new BitCodeAbbrev();
 214   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 216   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 217   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 218                             Log2_32_Ceil(VE.getTypes().size()+1)));
 219   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 220
 221   // Abbrev for TYPE_CODE_STRUCT_ANON.
 222   Abbv = new BitCodeAbbrev();
 223   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
 224   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 225   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 226   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 227                             Log2_32_Ceil(VE.getTypes().size()+1)));
 228   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 229
 230   // Abbrev for TYPE_CODE_STRUCT_NAME.
 231   Abbv = new BitCodeAbbrev();
 232   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
 233   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 234   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 235   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
 236
 237   // Abbrev for TYPE_CODE_STRUCT_NAMED.
 238   Abbv = new BitCodeAbbrev();
 239   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
 240   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 241   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 243                             Log2_32_Ceil(VE.getTypes().size()+1)));
 244   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
 245
 246   // Abbrev for TYPE_CODE_ARRAY.
 247   Abbv = new BitCodeAbbrev();
 248   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 249   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 250   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 251                             Log2_32_Ceil(VE.getTypes().size()+1)));
 252   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 253
 254   // Emit an entry count so the reader can reserve space.
 255   TypeVals.push_back(TypeList.size());
 256   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 257   TypeVals.clear();
 258
 259   // Loop over all of the types, emitting each in turn.
 260   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 261     Type *T = TypeList[i];
 262     int AbbrevToUse = 0;
 263     unsigned Code = 0;
 264
 265     switch (T->getTypeID()) {
 266     default: llvm_unreachable("Unknown type!");
 267     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
 268     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
 269     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
 270     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
 271     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128; break;
 272     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 273     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;  break;
 274     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA; break;
 275     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX; break;
 276     case Type::IntegerTyID:
 277       // INTEGER: [width]
 278       Code = bitc::TYPE_CODE_INTEGER;
 279       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 280       break;
 281     case Type::PointerTyID: {
 282       PointerType *PTy = cast<PointerType>(T);
 283       // POINTER: [pointee type, address space]
 284       Code = bitc::TYPE_CODE_POINTER;
 285       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 286       unsigned AddressSpace = PTy->getAddressSpace();
 287       TypeVals.push_back(AddressSpace);
 288       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 289       break;
 290     }
 291     case Type::FunctionTyID: {
 292       FunctionType *FT = cast<FunctionType>(T);
 293       // FUNCTION: [isvararg, retty, paramty x N]
 294       Code = bitc::TYPE_CODE_FUNCTION;
 295       TypeVals.push_back(FT->isVarArg());
 296       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 297       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 298         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 299       AbbrevToUse = FunctionAbbrev;
 300       break;
 301     }
 302     case Type::StructTyID: {
 303       StructType *ST = cast<StructType>(T);
 304       // STRUCT: [ispacked, eltty x N]
 305       TypeVals.push_back(ST->isPacked());
 306       // Output all of the element types.
 307       for (StructType::element_iterator I = ST->element_begin(),
 308            E = ST->element_end(); I != E; ++I)
 309         TypeVals.push_back(VE.getTypeID(*I));
 310
 311       if (ST->isLiteral()) {
 312         Code = bitc::TYPE_CODE_STRUCT_ANON;
 313         AbbrevToUse = StructAnonAbbrev;
 314       } else {
 315         if (ST->isOpaque()) {
 316           Code = bitc::TYPE_CODE_OPAQUE;
 317         } else {
 318           Code = bitc::TYPE_CODE_STRUCT_NAMED;
 319           AbbrevToUse = StructNamedAbbrev;
 320         }
 321
 322         // Emit the name if it is present.
 323         if (!ST->getName().empty())
 324           WriteStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
 325                             StructNameAbbrev, Stream);
 326       }
 327       break;
 328     }
 329     case Type::ArrayTyID: {
 330       ArrayType *AT = cast<ArrayType>(T);
 331       // ARRAY: [numelts, eltty]
 332       Code = bitc::TYPE_CODE_ARRAY;
 333       TypeVals.push_back(AT->getNumElements());
 334       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 335       AbbrevToUse = ArrayAbbrev;
 336       break;
 337     }
 338     case Type::VectorTyID: {
 339       VectorType *VT = cast<VectorType>(T);
 340       // VECTOR [numelts, eltty]
 341       Code = bitc::TYPE_CODE_VECTOR;
 342       TypeVals.push_back(VT->getNumElements());
 343       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 344       break;
 345     }
 346     }
 347
 348     // Emit the finished record.
 349     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 350     TypeVals.clear();
 351   }
 352
 353   Stream.ExitBlock();
 354 }
 355
 356 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 357   switch (GV->getLinkage()) {
 358   default: llvm_unreachable("Invalid linkage!");
 359   case GlobalValue::ExternalLinkage:                 return 0;
 360   case GlobalValue::WeakAnyLinkage:                  return 1;
 361   case GlobalValue::AppendingLinkage:                return 2;
 362   case GlobalValue::InternalLinkage:                 return 3;
 363   case GlobalValue::LinkOnceAnyLinkage:              return 4;
 364   case GlobalValue::DLLImportLinkage:                return 5;
 365   case GlobalValue::DLLExportLinkage:                return 6;
 366   case GlobalValue::ExternalWeakLinkage:             return 7;
 367   case GlobalValue::CommonLinkage:                   return 8;
 368   case GlobalValue::PrivateLinkage:                  return 9;
 369   case GlobalValue::WeakODRLinkage:                  return 10;
 370   case GlobalValue::LinkOnceODRLinkage:              return 11;
 371   case GlobalValue::AvailableExternallyLinkage:      return 12;
 372   case GlobalValue::LinkerPrivateLinkage:            return 13;
 373   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
 374   case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
 375   }
 376 }
 377
 378 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 379   switch (GV->getVisibility()) {
 380   default: llvm_unreachable("Invalid visibility!");
 381   case GlobalValue::DefaultVisibility:   return 0;
 382   case GlobalValue::HiddenVisibility:    return 1;
 383   case GlobalValue::ProtectedVisibility: return 2;
 384   }
 385 }
 386
 387 // Emit top-level description of module, including target triple, inline asm,
 388 // descriptors for global variables, and function prototype info.
 389 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 390                             BitstreamWriter &Stream) {
 391   // Emit the list of dependent libraries for the Module.
 392   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 393     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 394
 395   // Emit various pieces of data attached to a module.
 396   if (!M->getTargetTriple().empty())
 397     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 398                       0/*TODO*/, Stream);
 399   if (!M->getDataLayout().empty())
 400     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 401                       0/*TODO*/, Stream);
 402   if (!M->getModuleInlineAsm().empty())
 403     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 404                       0/*TODO*/, Stream);
 405
 406   // Emit information about sections and GC, computing how many there are. Also
 407   // compute the maximum alignment value.
 408   std::map<std::string, unsigned> SectionMap;
 409   std::map<std::string, unsigned> GCMap;
 410   unsigned MaxAlignment = 0;
 411   unsigned MaxGlobalType = 0;
 412   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 413        GV != E; ++GV) {
 414     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 415     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 416     if (GV->hasSection()) {
 417       // Give section names unique ID's.
 418       unsigned &Entry = SectionMap[GV->getSection()];
 419       if (!Entry) {
 420         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 421                           0/*TODO*/, Stream);
 422         Entry = SectionMap.size();
 423       }
 424     }
 425   }
 426   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 427     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 428     if (F->hasSection()) {
 429       // Give section names unique ID's.
 430       unsigned &Entry = SectionMap[F->getSection()];
 431       if (!Entry) {
 432         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 433                           0/*TODO*/, Stream);
 434         Entry = SectionMap.size();
 435       }
 436     }
 437     if (F->hasGC()) {
 438       // Same for GC names.
 439       unsigned &Entry = GCMap[F->getGC()];
 440       if (!Entry) {
 441         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 442                           0/*TODO*/, Stream);
 443         Entry = GCMap.size();
 444       }
 445     }
 446   }
 447
 448   // Emit abbrev for globals, now that we know # sections and max alignment.
 449   unsigned SimpleGVarAbbrev = 0;
 450   if (!M->global_empty()) {
 451     // Add an abbrev for common globals with no visibility or thread localness.
 452     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 453     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 455                               Log2_32_Ceil(MaxGlobalType+1)));
 456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 459     if (MaxAlignment == 0)                                      // Alignment.
 460       Abbv->Add(BitCodeAbbrevOp(0));
 461     else {
 462       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 463       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 464                                Log2_32_Ceil(MaxEncAlignment+1)));
 465     }
 466     if (SectionMap.empty())                                    // Section.
 467       Abbv->Add(BitCodeAbbrevOp(0));
 468     else
 469       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 470                                Log2_32_Ceil(SectionMap.size()+1)));
 471     // Don't bother emitting vis + thread local.
 472     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 473   }
 474
 475   // Emit the global variable information.
 476   SmallVector<unsigned, 64> Vals;
 477   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 478        GV != E; ++GV) {
 479     unsigned AbbrevToUse = 0;
 480
 481     // GLOBALVAR: [type, isconst, initid,
 482     //             linkage, alignment, section, visibility, threadlocal,
 483     //             unnamed_addr]
 484     Vals.push_back(VE.getTypeID(GV->getType()));
 485     Vals.push_back(GV->isConstant());
 486     Vals.push_back(GV->isDeclaration() ? 0 :
 487                    (VE.getValueID(GV->getInitializer()) + 1));
 488     Vals.push_back(getEncodedLinkage(GV));
 489     Vals.push_back(Log2_32(GV->getAlignment())+1);
 490     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 491     if (GV->isThreadLocal() ||
 492         GV->getVisibility() != GlobalValue::DefaultVisibility ||
 493         GV->hasUnnamedAddr()) {
 494       Vals.push_back(getEncodedVisibility(GV));
 495       Vals.push_back(GV->isThreadLocal());
 496       Vals.push_back(GV->hasUnnamedAddr());
 497     } else {
 498       AbbrevToUse = SimpleGVarAbbrev;
 499     }
 500
 501     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 502     Vals.clear();
 503   }
 504
 505   // Emit the function proto information.
 506   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 507     // FUNCTION:  [type, callingconv, isproto, paramattr,
 508     //             linkage, alignment, section, visibility, gc, unnamed_addr]
 509     Vals.push_back(VE.getTypeID(F->getType()));
 510     Vals.push_back(F->getCallingConv());
 511     Vals.push_back(F->isDeclaration());
 512     Vals.push_back(getEncodedLinkage(F));
 513     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 514     Vals.push_back(Log2_32(F->getAlignment())+1);
 515     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 516     Vals.push_back(getEncodedVisibility(F));
 517     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 518     Vals.push_back(F->hasUnnamedAddr());
 519
 520     unsigned AbbrevToUse = 0;
 521     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 522     Vals.clear();
 523   }
 524
 525   // Emit the alias information.
 526   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 527        AI != E; ++AI) {
 528     Vals.push_back(VE.getTypeID(AI->getType()));
 529     Vals.push_back(VE.getValueID(AI->getAliasee()));
 530     Vals.push_back(getEncodedLinkage(AI));
 531     Vals.push_back(getEncodedVisibility(AI));
 532     unsigned AbbrevToUse = 0;
 533     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 534     Vals.clear();
 535   }
 536 }
 537
 538 static uint64_t GetOptimizationFlags(const Value *V) {
 539   uint64_t Flags = 0;
 540
 541   if (const OverflowingBinaryOperator *OBO =
 542         dyn_cast<OverflowingBinaryOperator>(V)) {
 543     if (OBO->hasNoSignedWrap())
 544       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
 545     if (OBO->hasNoUnsignedWrap())
 546       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
 547   } else if (const PossiblyExactOperator *PEO =
 548                dyn_cast<PossiblyExactOperator>(V)) {
 549     if (PEO->isExact())
 550       Flags |= 1 << bitc::PEO_EXACT;
 551   }
 552
 553   return Flags;
 554 }
 555
 556 static void WriteMDNode(const MDNode *N,
 557                         const ValueEnumerator &VE,
 558                         BitstreamWriter &Stream,
 559                         SmallVector<uint64_t, 64> &Record) {
 560   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
 561     if (N->getOperand(i)) {
 562       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
 563       Record.push_back(VE.getValueID(N->getOperand(i)));
 564     } else {
 565       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
 566       Record.push_back(0);
 567     }
 568   }
 569   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
 570                                            bitc::METADATA_NODE;
 571   Stream.EmitRecord(MDCode, Record, 0);
 572   Record.clear();
 573 }
 574
 575 static void WriteModuleMetadata(const Module *M,
 576                                 const ValueEnumerator &VE,
 577                                 BitstreamWriter &Stream) {
 578   const ValueEnumerator::ValueList &Vals = VE.getMDValues();
 579   bool StartedMetadataBlock = false;
 580   unsigned MDSAbbrev = 0;
 581   SmallVector<uint64_t, 64> Record;
 582   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 583
 584     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
 585       if (!N->isFunctionLocal() || !N->getFunction()) {
 586         if (!StartedMetadataBlock) {
 587           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 588           StartedMetadataBlock = true;
 589         }
 590         WriteMDNode(N, VE, Stream, Record);
 591       }
 592     } else if (const MDString *MDS = dyn_cast<MDString>(Vals[i].first)) {
 593       if (!StartedMetadataBlock)  {
 594         Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 595
 596         // Abbrev for METADATA_STRING.
 597         BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 598         Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRING));
 599         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 600         Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 601         MDSAbbrev = Stream.EmitAbbrev(Abbv);
 602         StartedMetadataBlock = true;
 603       }
 604
 605       // Code: [strchar x N]
 606       Record.append(MDS->begin(), MDS->end());
 607
 608       // Emit the finished record.
 609       Stream.EmitRecord(bitc::METADATA_STRING, Record, MDSAbbrev);
 610       Record.clear();
 611     }
 612   }
 613
 614   // Write named metadata.
 615   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
 616        E = M->named_metadata_end(); I != E; ++I) {
 617     const NamedMDNode *NMD = I;
 618     if (!StartedMetadataBlock)  {
 619       Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 620       StartedMetadataBlock = true;
 621     }
 622
 623     // Write name.
 624     StringRef Str = NMD->getName();
 625     for (unsigned i = 0, e = Str.size(); i != e; ++i)
 626       Record.push_back(Str[i]);
 627     Stream.EmitRecord(bitc::METADATA_NAME, Record, 0/*TODO*/);
 628     Record.clear();
 629
 630     // Write named metadata operands.
 631     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
 632       Record.push_back(VE.getValueID(NMD->getOperand(i)));
 633     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
 634     Record.clear();
 635   }
 636
 637   if (StartedMetadataBlock)
 638     Stream.ExitBlock();
 639 }
 640
 641 static void WriteFunctionLocalMetadata(const Function &F,
 642                                        const ValueEnumerator &VE,
 643                                        BitstreamWriter &Stream) {
 644   bool StartedMetadataBlock = false;
 645   SmallVector<uint64_t, 64> Record;
 646   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
 647   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
 648     if (const MDNode *N = Vals[i])
 649       if (N->isFunctionLocal() && N->getFunction() == &F) {
 650         if (!StartedMetadataBlock) {
 651           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 652           StartedMetadataBlock = true;
 653         }
 654         WriteMDNode(N, VE, Stream, Record);
 655       }
 656
 657   if (StartedMetadataBlock)
 658     Stream.ExitBlock();
 659 }
 660
 661 static void WriteMetadataAttachment(const Function &F,
 662                                     const ValueEnumerator &VE,
 663                                     BitstreamWriter &Stream) {
 664   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 665
 666   SmallVector<uint64_t, 64> Record;
 667
 668   // Write metadata attachments
 669   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
 670   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 671
 672   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
 673     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
 674          I != E; ++I) {
 675       MDs.clear();
 676       I->getAllMetadataOtherThanDebugLoc(MDs);
 677
 678       // If no metadata, ignore instruction.
 679       if (MDs.empty()) continue;
 680
 681       Record.push_back(VE.getInstructionID(I));
 682
 683       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
 684         Record.push_back(MDs[i].first);
 685         Record.push_back(VE.getValueID(MDs[i].second));
 686       }
 687       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
 688       Record.clear();
 689     }
 690
 691   Stream.ExitBlock();
 692 }
 693
 694 static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
 695   SmallVector<uint64_t, 64> Record;
 696
 697   // Write metadata kinds
 698   // METADATA_KIND - [n x [id, name]]
 699   SmallVector<StringRef, 4> Names;
 700   M->getMDKindNames(Names);
 701
 702   if (Names.empty()) return;
 703
 704   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
 705
 706   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
 707     Record.push_back(MDKindID);
 708     StringRef KName = Names[MDKindID];
 709     Record.append(KName.begin(), KName.end());
 710
 711     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
 712     Record.clear();
 713   }
 714
 715   Stream.ExitBlock();
 716 }
 717
 718 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 719                            const ValueEnumerator &VE,
 720                            BitstreamWriter &Stream, bool isGlobal) {
 721   if (FirstVal == LastVal) return;
 722
 723   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 724
 725   unsigned AggregateAbbrev = 0;
 726   unsigned String8Abbrev = 0;
 727   unsigned CString7Abbrev = 0;
 728   unsigned CString6Abbrev = 0;
 729   // If this is a constant pool for the module, emit module-specific abbrevs.
 730   if (isGlobal) {
 731     // Abbrev for CST_CODE_AGGREGATE.
 732     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 733     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 734     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 735     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 736     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 737
 738     // Abbrev for CST_CODE_STRING.
 739     Abbv = new BitCodeAbbrev();
 740     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 741     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 742     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 743     String8Abbrev = Stream.EmitAbbrev(Abbv);
 744     // Abbrev for CST_CODE_CSTRING.
 745     Abbv = new BitCodeAbbrev();
 746     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 747     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 748     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 749     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 750     // Abbrev for CST_CODE_CSTRING.
 751     Abbv = new BitCodeAbbrev();
 752     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 753     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 754     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 755     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 756   }
 757
 758   SmallVector<uint64_t, 64> Record;
 759
 760   const ValueEnumerator::ValueList &Vals = VE.getValues();
 761   Type *LastTy = 0;
 762   for (unsigned i = FirstVal; i != LastVal; ++i) {
 763     const Value *V = Vals[i].first;
 764     // If we need to switch types, do so now.
 765     if (V->getType() != LastTy) {
 766       LastTy = V->getType();
 767       Record.push_back(VE.getTypeID(LastTy));
 768       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 769                         CONSTANTS_SETTYPE_ABBREV);
 770       Record.clear();
 771     }
 772
 773     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 774       Record.push_back(unsigned(IA->hasSideEffects()) |
 775                        unsigned(IA->isAlignStack()) << 1);
 776
 777       // Add the asm string.
 778       const std::string &AsmStr = IA->getAsmString();
 779       Record.push_back(AsmStr.size());
 780       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 781         Record.push_back(AsmStr[i]);
 782
 783       // Add the constraint string.
 784       const std::string &ConstraintStr = IA->getConstraintString();
 785       Record.push_back(ConstraintStr.size());
 786       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 787         Record.push_back(ConstraintStr[i]);
 788       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 789       Record.clear();
 790       continue;
 791     }
 792     const Constant *C = cast<Constant>(V);
 793     unsigned Code = -1U;
 794     unsigned AbbrevToUse = 0;
 795     if (C->isNullValue()) {
 796       Code = bitc::CST_CODE_NULL;
 797     } else if (isa<UndefValue>(C)) {
 798       Code = bitc::CST_CODE_UNDEF;
 799     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 800       if (IV->getBitWidth() <= 64) {
 801         uint64_t V = IV->getSExtValue();
 802         if ((int64_t)V >= 0)
 803           Record.push_back(V << 1);
 804         else
 805           Record.push_back((-V << 1) | 1);
 806         Code = bitc::CST_CODE_INTEGER;
 807         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 808       } else {                             // Wide integers, > 64 bits in size.
 809         // We have an arbitrary precision integer value to write whose
 810         // bit width is > 64. However, in canonical unsigned integer
 811         // format it is likely that the high bits are going to be zero.
 812         // So, we only write the number of active words.
 813         unsigned NWords = IV->getValue().getActiveWords();
 814         const uint64_t *RawWords = IV->getValue().getRawData();
 815         for (unsigned i = 0; i != NWords; ++i) {
 816           int64_t V = RawWords[i];
 817           if (V >= 0)
 818             Record.push_back(V << 1);
 819           else
 820             Record.push_back((-V << 1) | 1);
 821         }
 822         Code = bitc::CST_CODE_WIDE_INTEGER;
 823       }
 824     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 825       Code = bitc::CST_CODE_FLOAT;
 826       Type *Ty = CFP->getType();
 827       if (Ty->isFloatTy() || Ty->isDoubleTy()) {
 828         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 829       } else if (Ty->isX86_FP80Ty()) {
 830         // api needed to prevent premature destruction
 831         // bits are not in the same order as a normal i80 APInt, compensate.
 832         APInt api = CFP->getValueAPF().bitcastToAPInt();
 833         const uint64_t *p = api.getRawData();
 834         Record.push_back((p[1] << 48) | (p[0] >> 16));
 835         Record.push_back(p[0] & 0xffffLL);
 836       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
 837         APInt api = CFP->getValueAPF().bitcastToAPInt();
 838         const uint64_t *p = api.getRawData();
 839         Record.push_back(p[0]);
 840         Record.push_back(p[1]);
 841       } else {
 842         assert (0 && "Unknown FP type!");
 843       }
 844     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 845       const ConstantArray *CA = cast<ConstantArray>(C);
 846       // Emit constant strings specially.
 847       unsigned NumOps = CA->getNumOperands();
 848       // If this is a null-terminated string, use the denser CSTRING encoding.
 849       if (CA->getOperand(NumOps-1)->isNullValue()) {
 850         Code = bitc::CST_CODE_CSTRING;
 851         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 852       } else {
 853         Code = bitc::CST_CODE_STRING;
 854         AbbrevToUse = String8Abbrev;
 855       }
 856       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 857       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 858       for (unsigned i = 0; i != NumOps; ++i) {
 859         unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
 860         Record.push_back(V);
 861         isCStr7 &= (V & 128) == 0;
 862         if (isCStrChar6)
 863           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 864       }
 865
 866       if (isCStrChar6)
 867         AbbrevToUse = CString6Abbrev;
 868       else if (isCStr7)
 869         AbbrevToUse = CString7Abbrev;
 870     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 871                isa<ConstantVector>(V)) {
 872       Code = bitc::CST_CODE_AGGREGATE;
 873       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 874         Record.push_back(VE.getValueID(C->getOperand(i)));
 875       AbbrevToUse = AggregateAbbrev;
 876     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 877       switch (CE->getOpcode()) {
 878       default:
 879         if (Instruction::isCast(CE->getOpcode())) {
 880           Code = bitc::CST_CODE_CE_CAST;
 881           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 882           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 883           Record.push_back(VE.getValueID(C->getOperand(0)));
 884           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 885         } else {
 886           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 887           Code = bitc::CST_CODE_CE_BINOP;
 888           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 889           Record.push_back(VE.getValueID(C->getOperand(0)));
 890           Record.push_back(VE.getValueID(C->getOperand(1)));
 891           uint64_t Flags = GetOptimizationFlags(CE);
 892           if (Flags != 0)
 893             Record.push_back(Flags);
 894         }
 895         break;
 896       case Instruction::GetElementPtr:
 897         Code = bitc::CST_CODE_CE_GEP;
 898         if (cast<GEPOperator>(C)->isInBounds())
 899           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
 900         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 901           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 902           Record.push_back(VE.getValueID(C->getOperand(i)));
 903         }
 904         break;
 905       case Instruction::Select:
 906         Code = bitc::CST_CODE_CE_SELECT;
 907         Record.push_back(VE.getValueID(C->getOperand(0)));
 908         Record.push_back(VE.getValueID(C->getOperand(1)));
 909         Record.push_back(VE.getValueID(C->getOperand(2)));
 910         break;
 911       case Instruction::ExtractElement:
 912         Code = bitc::CST_CODE_CE_EXTRACTELT;
 913         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 914         Record.push_back(VE.getValueID(C->getOperand(0)));
 915         Record.push_back(VE.getValueID(C->getOperand(1)));
 916         break;
 917       case Instruction::InsertElement:
 918         Code = bitc::CST_CODE_CE_INSERTELT;
 919         Record.push_back(VE.getValueID(C->getOperand(0)));
 920         Record.push_back(VE.getValueID(C->getOperand(1)));
 921         Record.push_back(VE.getValueID(C->getOperand(2)));
 922         break;
 923       case Instruction::ShuffleVector:
 924         // If the return type and argument types are the same, this is a
 925         // standard shufflevector instruction.  If the types are different,
 926         // then the shuffle is widening or truncating the input vectors, and
 927         // the argument type must also be encoded.
 928         if (C->getType() == C->getOperand(0)->getType()) {
 929           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 930         } else {
 931           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
 932           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 933         }
 934         Record.push_back(VE.getValueID(C->getOperand(0)));
 935         Record.push_back(VE.getValueID(C->getOperand(1)));
 936         Record.push_back(VE.getValueID(C->getOperand(2)));
 937         break;
 938       case Instruction::ICmp:
 939       case Instruction::FCmp:
 940         Code = bitc::CST_CODE_CE_CMP;
 941         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 942         Record.push_back(VE.getValueID(C->getOperand(0)));
 943         Record.push_back(VE.getValueID(C->getOperand(1)));
 944         Record.push_back(CE->getPredicate());
 945         break;
 946       }
 947     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
 948       Code = bitc::CST_CODE_BLOCKADDRESS;
 949       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
 950       Record.push_back(VE.getValueID(BA->getFunction()));
 951       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
 952     } else {
 953 #ifndef NDEBUG
 954       C->dump();
 955 #endif
 956       llvm_unreachable("Unknown constant!");
 957     }
 958     Stream.EmitRecord(Code, Record, AbbrevToUse);
 959     Record.clear();
 960   }
 961
 962   Stream.ExitBlock();
 963 }
 964
 965 static void WriteModuleConstants(const ValueEnumerator &VE,
 966                                  BitstreamWriter &Stream) {
 967   const ValueEnumerator::ValueList &Vals = VE.getValues();
 968
 969   // Find the first constant to emit, which is the first non-globalvalue value.
 970   // We know globalvalues have been emitted by WriteModuleInfo.
 971   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 972     if (!isa<GlobalValue>(Vals[i].first)) {
 973       WriteConstants(i, Vals.size(), VE, Stream, true);
 974       return;
 975     }
 976   }
 977 }
 978
 979 /// PushValueAndType - The file has to encode both the value and type id for
 980 /// many values, because we need to know what type to create for forward
 981 /// references.  However, most operands are not forward references, so this type
 982 /// field is not needed.
 983 ///
 984 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 985 /// instruction ID, then it is a forward reference, and it also includes the
 986 /// type ID.
 987 static bool PushValueAndType(const Value *V, unsigned InstID,
 988                              SmallVector<unsigned, 64> &Vals,
 989                              ValueEnumerator &VE) {
 990   unsigned ValID = VE.getValueID(V);
 991   Vals.push_back(ValID);
 992   if (ValID >= InstID) {
 993     Vals.push_back(VE.getTypeID(V->getType()));
 994     return true;
 995   }
 996   return false;
 997 }
 998
 999 /// WriteInstruction - Emit an instruction to the specified stream.
1000 static void WriteInstruction(const Instruction &I, unsigned InstID,
1001                              ValueEnumerator &VE, BitstreamWriter &Stream,
1002                              SmallVector<unsigned, 64> &Vals) {
1003   unsigned Code = 0;
1004   unsigned AbbrevToUse = 0;
1005   VE.setInstructionID(&I);
1006   switch (I.getOpcode()) {
1007   default:
1008     if (Instruction::isCast(I.getOpcode())) {
1009       Code = bitc::FUNC_CODE_INST_CAST;
1010       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1011         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
1012       Vals.push_back(VE.getTypeID(I.getType()));
1013       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
1014     } else {
1015       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
1016       Code = bitc::FUNC_CODE_INST_BINOP;
1017       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1018         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
1019       Vals.push_back(VE.getValueID(I.getOperand(1)));
1020       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
1021       uint64_t Flags = GetOptimizationFlags(&I);
1022       if (Flags != 0) {
1023         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
1024           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
1025         Vals.push_back(Flags);
1026       }
1027     }
1028     break;
1029
1030   case Instruction::GetElementPtr:
1031     Code = bitc::FUNC_CODE_INST_GEP;
1032     if (cast<GEPOperator>(&I)->isInBounds())
1033       Code = bitc::FUNC_CODE_INST_INBOUNDS_GEP;
1034     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1035       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1036     break;
1037   case Instruction::ExtractValue: {
1038     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
1039     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1040     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
1041     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
1042       Vals.push_back(*i);
1043     break;
1044   }
1045   case Instruction::InsertValue: {
1046     Code = bitc::FUNC_CODE_INST_INSERTVAL;
1047     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1048     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1049     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
1050     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
1051       Vals.push_back(*i);
1052     break;
1053   }
1054   case Instruction::Select:
1055     Code = bitc::FUNC_CODE_INST_VSELECT;
1056     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
1057     Vals.push_back(VE.getValueID(I.getOperand(2)));
1058     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1059     break;
1060   case Instruction::ExtractElement:
1061     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
1062     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1063     Vals.push_back(VE.getValueID(I.getOperand(1)));
1064     break;
1065   case Instruction::InsertElement:
1066     Code = bitc::FUNC_CODE_INST_INSERTELT;
1067     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1068     Vals.push_back(VE.getValueID(I.getOperand(1)));
1069     Vals.push_back(VE.getValueID(I.getOperand(2)));
1070     break;
1071   case Instruction::ShuffleVector:
1072     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
1073     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1074     Vals.push_back(VE.getValueID(I.getOperand(1)));
1075     Vals.push_back(VE.getValueID(I.getOperand(2)));
1076     break;
1077   case Instruction::ICmp:
1078   case Instruction::FCmp:
1079     // compare returning Int1Ty or vector of Int1Ty
1080     Code = bitc::FUNC_CODE_INST_CMP2;
1081     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1082     Vals.push_back(VE.getValueID(I.getOperand(1)));
1083     Vals.push_back(cast<CmpInst>(I).getPredicate());
1084     break;
1085
1086   case Instruction::Ret:
1087     {
1088       Code = bitc::FUNC_CODE_INST_RET;
1089       unsigned NumOperands = I.getNumOperands();
1090       if (NumOperands == 0)
1091         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
1092       else if (NumOperands == 1) {
1093         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
1094           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
1095       } else {
1096         for (unsigned i = 0, e = NumOperands; i != e; ++i)
1097           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
1098       }
1099     }
1100     break;
1101   case Instruction::Br:
1102     {
1103       Code = bitc::FUNC_CODE_INST_BR;
1104       BranchInst &II = cast<BranchInst>(I);
1105       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
1106       if (II.isConditional()) {
1107         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
1108         Vals.push_back(VE.getValueID(II.getCondition()));
1109       }
1110     }
1111     break;
1112   case Instruction::Switch:
1113     Code = bitc::FUNC_CODE_INST_SWITCH;
1114     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1115     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1116       Vals.push_back(VE.getValueID(I.getOperand(i)));
1117     break;
1118   case Instruction::IndirectBr:
1119     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
1120     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1121     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
1122       Vals.push_back(VE.getValueID(I.getOperand(i)));
1123     break;
1124
1125   case Instruction::Invoke: {
1126     const InvokeInst *II = cast<InvokeInst>(&I);
1127     const Value *Callee(II->getCalledValue());
1128     PointerType *PTy = cast<PointerType>(Callee->getType());
1129     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1130     Code = bitc::FUNC_CODE_INST_INVOKE;
1131
1132     Vals.push_back(VE.getAttributeID(II->getAttributes()));
1133     Vals.push_back(II->getCallingConv());
1134     Vals.push_back(VE.getValueID(II->getNormalDest()));
1135     Vals.push_back(VE.getValueID(II->getUnwindDest()));
1136     PushValueAndType(Callee, InstID, Vals, VE);
1137
1138     // Emit value #'s for the fixed parameters.
1139     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1140       Vals.push_back(VE.getValueID(I.getOperand(i)));  // fixed param.
1141
1142     // Emit type/value pairs for varargs params.
1143     if (FTy->isVarArg()) {
1144       for (unsigned i = FTy->getNumParams(), e = I.getNumOperands()-3;
1145            i != e; ++i)
1146         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
1147     }
1148     break;
1149   }
1150   case Instruction::Resume:
1151     Code = bitc::FUNC_CODE_INST_RESUME;
1152     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1153     break;
1154   case Instruction::Unwind:
1155     Code = bitc::FUNC_CODE_INST_UNWIND;
1156     break;
1157   case Instruction::Unreachable:
1158     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
1159     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
1160     break;
1161
1162   case Instruction::PHI: {
1163     const PHINode &PN = cast<PHINode>(I);
1164     Code = bitc::FUNC_CODE_INST_PHI;
1165     Vals.push_back(VE.getTypeID(PN.getType()));
1166     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
1167       Vals.push_back(VE.getValueID(PN.getIncomingValue(i)));
1168       Vals.push_back(VE.getValueID(PN.getIncomingBlock(i)));
1169     }
1170     break;
1171   }
1172
1173   case Instruction::LandingPad: {
1174     const LandingPadInst &LP = cast<LandingPadInst>(I);
1175     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
1176     Vals.push_back(VE.getTypeID(LP.getType()));
1177     PushValueAndType(LP.getPersonalityFn(), InstID, Vals, VE);
1178     Vals.push_back(LP.isCleanup());
1179     Vals.push_back(LP.getNumClauses());
1180     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
1181       if (LP.isCatch(I))
1182         Vals.push_back(LandingPadInst::Catch);
1183       else
1184         Vals.push_back(LandingPadInst::Filter);
1185       PushValueAndType(LP.getClause(I), InstID, Vals, VE);
1186     }
1187     break;
1188   }
1189
1190   case Instruction::Alloca:
1191     Code = bitc::FUNC_CODE_INST_ALLOCA;
1192     Vals.push_back(VE.getTypeID(I.getType()));
1193     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
1194     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
1195     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
1196     break;
1197
1198   case Instruction::Load:
1199     if (cast<LoadInst>(I).isAtomic()) {
1200       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
1201       PushValueAndType(I.getOperand(0), InstID, Vals, VE);
1202     } else {
1203       Code = bitc::FUNC_CODE_INST_LOAD;
1204       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
1205         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
1206     }
1207     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
1208     Vals.push_back(cast<LoadInst>(I).isVolatile());
1209     if (cast<LoadInst>(I).isAtomic()) {
1210       Vals.push_back(GetEncodedOrdering(cast<LoadInst>(I).getOrdering()));
1211       Vals.push_back(GetEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
1212     }
1213     break;
1214   case Instruction::Store:
1215     if (cast<StoreInst>(I).isAtomic())
1216       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
1217     else
1218       Code = bitc::FUNC_CODE_INST_STORE;
1219     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
1220     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
1221     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
1222     Vals.push_back(cast<StoreInst>(I).isVolatile());
1223     if (cast<StoreInst>(I).isAtomic()) {
1224       Vals.push_back(GetEncodedOrdering(cast<StoreInst>(I).getOrdering()));
1225       Vals.push_back(GetEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
1226     }
1227     break;
1228   case Instruction::AtomicCmpXchg:
1229     Code = bitc::FUNC_CODE_INST_CMPXCHG;
1230     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1231     Vals.push_back(VE.getValueID(I.getOperand(1)));       // cmp.
1232     Vals.push_back(VE.getValueID(I.getOperand(2)));       // newval.
1233     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
1234     Vals.push_back(GetEncodedOrdering(
1235                      cast<AtomicCmpXchgInst>(I).getOrdering()));
1236     Vals.push_back(GetEncodedSynchScope(
1237                      cast<AtomicCmpXchgInst>(I).getSynchScope()));
1238     break;
1239   case Instruction::AtomicRMW:
1240     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
1241     PushValueAndType(I.getOperand(0), InstID, Vals, VE);  // ptrty + ptr
1242     Vals.push_back(VE.getValueID(I.getOperand(1)));       // val.
1243     Vals.push_back(GetEncodedRMWOperation(
1244                      cast<AtomicRMWInst>(I).getOperation()));
1245     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
1246     Vals.push_back(GetEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
1247     Vals.push_back(GetEncodedSynchScope(
1248                      cast<AtomicRMWInst>(I).getSynchScope()));
1249     break;
1250   case Instruction::Fence:
1251     Code = bitc::FUNC_CODE_INST_FENCE;
1252     Vals.push_back(GetEncodedOrdering(cast<FenceInst>(I).getOrdering()));
1253     Vals.push_back(GetEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
1254     break;
1255   case Instruction::Call: {
1256     const CallInst &CI = cast<CallInst>(I);
1257     PointerType *PTy = cast<PointerType>(CI.getCalledValue()->getType());
1258     FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
1259
1260     Code = bitc::FUNC_CODE_INST_CALL;
1261
1262     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
1263     Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()));
1264     PushValueAndType(CI.getCalledValue(), InstID, Vals, VE);  // Callee
1265
1266     // Emit value #'s for the fixed parameters.
1267     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
1268       Vals.push_back(VE.getValueID(CI.getArgOperand(i)));  // fixed param.
1269
1270     // Emit type/value pairs for varargs params.
1271     if (FTy->isVarArg()) {
1272       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
1273            i != e; ++i)
1274         PushValueAndType(CI.getArgOperand(i), InstID, Vals, VE);  // varargs
1275     }
1276     break;
1277   }
1278   case Instruction::VAArg:
1279     Code = bitc::FUNC_CODE_INST_VAARG;
1280     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
1281     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
1282     Vals.push_back(VE.getTypeID(I.getType())); // restype.
1283     break;
1284   }
1285
1286   Stream.EmitRecord(Code, Vals, AbbrevToUse);
1287   Vals.clear();
1288 }
1289
1290 // Emit names for globals/functions etc.
1291 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
1292                                   const ValueEnumerator &VE,
1293                                   BitstreamWriter &Stream) {
1294   if (VST.empty()) return;
1295   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
1296
1297   // FIXME: Set up the abbrev, we know how many values there are!
1298   // FIXME: We know if the type names can use 7-bit ascii.
1299   SmallVector<unsigned, 64> NameVals;
1300
1301   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
1302        SI != SE; ++SI) {
1303
1304     const ValueName &Name = *SI;
1305
1306     // Figure out the encoding to use for the name.
1307     bool is7Bit = true;
1308     bool isChar6 = true;
1309     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
1310          C != E; ++C) {
1311       if (isChar6)
1312         isChar6 = BitCodeAbbrevOp::isChar6(*C);
1313       if ((unsigned char)*C & 128) {
1314         is7Bit = false;
1315         break;  // don't bother scanning the rest.
1316       }
1317     }
1318
1319     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
1320
1321     // VST_ENTRY:   [valueid, namechar x N]
1322     // VST_BBENTRY: [bbid, namechar x N]
1323     unsigned Code;
1324     if (isa<BasicBlock>(SI->getValue())) {
1325       Code = bitc::VST_CODE_BBENTRY;
1326       if (isChar6)
1327         AbbrevToUse = VST_BBENTRY_6_ABBREV;
1328     } else {
1329       Code = bitc::VST_CODE_ENTRY;
1330       if (isChar6)
1331         AbbrevToUse = VST_ENTRY_6_ABBREV;
1332       else if (is7Bit)
1333         AbbrevToUse = VST_ENTRY_7_ABBREV;
1334     }
1335
1336     NameVals.push_back(VE.getValueID(SI->getValue()));
1337     for (const char *P = Name.getKeyData(),
1338          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
1339       NameVals.push_back((unsigned char)*P);
1340
1341     // Emit the finished record.
1342     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
1343     NameVals.clear();
1344   }
1345   Stream.ExitBlock();
1346 }
1347
1348 /// WriteFunction - Emit a function body to the module stream.
1349 static void WriteFunction(const Function &F, ValueEnumerator &VE,
1350                           BitstreamWriter &Stream) {
1351   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
1352   VE.incorporateFunction(F);
1353
1354   SmallVector<unsigned, 64> Vals;
1355
1356   // Emit the number of basic blocks, so the reader can create them ahead of
1357   // time.
1358   Vals.push_back(VE.getBasicBlocks().size());
1359   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
1360   Vals.clear();
1361
1362   // If there are function-local constants, emit them now.
1363   unsigned CstStart, CstEnd;
1364   VE.getFunctionConstantRange(CstStart, CstEnd);
1365   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1366
1367   // If there is function-local metadata, emit it now.
1368   WriteFunctionLocalMetadata(F, VE, Stream);
1369
1370   // Keep a running idea of what the instruction ID is.
1371   unsigned InstID = CstEnd;
1372
1373   bool NeedsMetadataAttachment = false;
1374
1375   DebugLoc LastDL;
1376
1377   // Finally, emit all the instructions, in order.
1378   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1379     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1380          I != E; ++I) {
1381       WriteInstruction(*I, InstID, VE, Stream, Vals);
1382
1383       if (!I->getType()->isVoidTy())
1384         ++InstID;
1385
1386       // If the instruction has metadata, write a metadata attachment later.
1387       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
1388
1389       // If the instruction has a debug location, emit it.
1390       DebugLoc DL = I->getDebugLoc();
1391       if (DL.isUnknown()) {
1392         // nothing todo.
1393       } else if (DL == LastDL) {
1394         // Just repeat the same debug loc as last time.
1395         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
1396       } else {
1397         MDNode *Scope, *IA;
1398         DL.getScopeAndInlinedAt(Scope, IA, I->getContext());
1399
1400         Vals.push_back(DL.getLine());
1401         Vals.push_back(DL.getCol());
1402         Vals.push_back(Scope ? VE.getValueID(Scope)+1 : 0);
1403         Vals.push_back(IA ? VE.getValueID(IA)+1 : 0);
1404         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
1405         Vals.clear();
1406
1407         LastDL = DL;
1408       }
1409     }
1410
1411   // Emit names for all the instructions etc.
1412   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1413
1414   if (NeedsMetadataAttachment)
1415     WriteMetadataAttachment(F, VE, Stream);
1416   VE.purgeFunction();
1417   Stream.ExitBlock();
1418 }
1419
1420 // Emit blockinfo, which defines the standard abbreviations etc.
1421 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1422   // We only want to emit block info records for blocks that have multiple
1423   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1424   // blocks can defined their abbrevs inline.
1425   Stream.EnterBlockInfoBlock(2);
1426
1427   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1428     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1433     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1434                                    Abbv) != VST_ENTRY_8_ABBREV)
1435       llvm_unreachable("Unexpected abbrev ordering!");
1436   }
1437
1438   { // 7-bit fixed width VST_ENTRY strings.
1439     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1440     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1444     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1445                                    Abbv) != VST_ENTRY_7_ABBREV)
1446       llvm_unreachable("Unexpected abbrev ordering!");
1447   }
1448   { // 6-bit char6 VST_ENTRY strings.
1449     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1450     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1454     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1455                                    Abbv) != VST_ENTRY_6_ABBREV)
1456       llvm_unreachable("Unexpected abbrev ordering!");
1457   }
1458   { // 6-bit char6 VST_BBENTRY strings.
1459     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1460     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1464     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1465                                    Abbv) != VST_BBENTRY_6_ABBREV)
1466       llvm_unreachable("Unexpected abbrev ordering!");
1467   }
1468
1469
1470
1471   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1472     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1473     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1474     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1475                               Log2_32_Ceil(VE.getTypes().size()+1)));
1476     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1477                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1478       llvm_unreachable("Unexpected abbrev ordering!");
1479   }
1480
1481   { // INTEGER abbrev for CONSTANTS_BLOCK.
1482     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1483     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1485     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1486                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1487       llvm_unreachable("Unexpected abbrev ordering!");
1488   }
1489
1490   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1491     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1492     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1495                               Log2_32_Ceil(VE.getTypes().size()+1)));
1496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1497
1498     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1499                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1500       llvm_unreachable("Unexpected abbrev ordering!");
1501   }
1502   { // NULL abbrev for CONSTANTS_BLOCK.
1503     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1504     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1505     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1506                                    Abbv) != CONSTANTS_NULL_Abbrev)
1507       llvm_unreachable("Unexpected abbrev ordering!");
1508   }
1509
1510   // FIXME: This should only use space for first class types!
1511
1512   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1513     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1514     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1518     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1519                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1520       llvm_unreachable("Unexpected abbrev ordering!");
1521   }
1522   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1523     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1524     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1528     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1529                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1530       llvm_unreachable("Unexpected abbrev ordering!");
1531   }
1532   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
1533     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1534     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
1539     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1540                                    Abbv) != FUNCTION_INST_BINOP_FLAGS_ABBREV)
1541       llvm_unreachable("Unexpected abbrev ordering!");
1542   }
1543   { // INST_CAST abbrev for FUNCTION_BLOCK.
1544     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1545     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1548                               Log2_32_Ceil(VE.getTypes().size()+1)));
1549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1550     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1551                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1552       llvm_unreachable("Unexpected abbrev ordering!");
1553   }
1554
1555   { // INST_RET abbrev for FUNCTION_BLOCK.
1556     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1557     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1558     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1559                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1560       llvm_unreachable("Unexpected abbrev ordering!");
1561   }
1562   { // INST_RET abbrev for FUNCTION_BLOCK.
1563     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1564     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1565     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1566     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1567                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1568       llvm_unreachable("Unexpected abbrev ordering!");
1569   }
1570   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1571     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1572     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1573     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1574                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1575       llvm_unreachable("Unexpected abbrev ordering!");
1576   }
1577
1578   Stream.ExitBlock();
1579 }
1580
1581 // Sort the Users based on the order in which the reader parses the bitcode
1582 // file.
1583 static bool bitcodereader_order(const User *lhs, const User *rhs) {
1584   // TODO: Implement.
1585   return true;
1586 }
1587
1588 static void WriteUseList(const Value *V, const ValueEnumerator &VE,
1589                          BitstreamWriter &Stream) {
1590
1591   // One or zero uses can't get out of order.
1592   if (V->use_empty() || V->hasNUses(1))
1593     return;
1594
1595   // Make a copy of the in-memory use-list for sorting.
1596   unsigned UseListSize = std::distance(V->use_begin(), V->use_end());
1597   SmallVector<const User*, 8> UseList;
1598   UseList.reserve(UseListSize);
1599   for (Value::const_use_iterator I = V->use_begin(), E = V->use_end();
1600        I != E; ++I) {
1601     const User *U = *I;
1602     UseList.push_back(U);
1603   }
1604
1605   // Sort the copy based on the order read by the BitcodeReader.
1606   std::sort(UseList.begin(), UseList.end(), bitcodereader_order);
1607
1608   // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
1609   // sorted list (i.e., the expected BitcodeReader in-memory use-list).
1610
1611   // TODO: Emit the USELIST_CODE_ENTRYs.
1612 }
1613
1614 static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
1615                                  BitstreamWriter &Stream) {
1616   VE.incorporateFunction(*F);
1617
1618   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
1619        AI != AE; ++AI)
1620     WriteUseList(AI, VE, Stream);
1621   for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
1622        ++BB) {
1623     WriteUseList(BB, VE, Stream);
1624     for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
1625          ++II) {
1626       WriteUseList(II, VE, Stream);
1627       for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
1628            OI != E; ++OI) {
1629         if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
1630             isa<InlineAsm>(*OI))
1631           WriteUseList(*OI, VE, Stream);
1632       }
1633     }
1634   }
1635   VE.purgeFunction();
1636 }
1637
1638 // Emit use-lists.
1639 static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
1640                                 BitstreamWriter &Stream) {
1641   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
1642
1643   // XXX: this modifies the module, but in a way that should never change the
1644   // behavior of any pass or codegen in LLVM. The problem is that GVs may
1645   // contain entries in the use_list that do not exist in the Module and are
1646   // not stored in the .bc file.
1647   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
1648        I != E; ++I)
1649     I->removeDeadConstantUsers();
1650
1651   // Write the global variables.
1652   for (Module::const_global_iterator GI = M->global_begin(),
1653          GE = M->global_end(); GI != GE; ++GI) {
1654     WriteUseList(GI, VE, Stream);
1655
1656     // Write the global variable initializers.
1657     if (GI->hasInitializer())
1658       WriteUseList(GI->getInitializer(), VE, Stream);
1659   }
1660
1661   // Write the functions.
1662   for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
1663     WriteUseList(FI, VE, Stream);
1664     if (!FI->isDeclaration())
1665       WriteFunctionUseList(FI, VE, Stream);
1666   }
1667
1668   // Write the aliases.
1669   for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
1670        AI != AE; ++AI) {
1671     WriteUseList(AI, VE, Stream);
1672     WriteUseList(AI->getAliasee(), VE, Stream);
1673   }
1674
1675   Stream.ExitBlock();
1676 }
1677
1678 /// WriteModule - Emit the specified module to the bitstream.
1679 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1680   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1681
1682   // Emit the version number if it is non-zero.
1683   if (CurVersion) {
1684     SmallVector<unsigned, 1> Vals;
1685     Vals.push_back(CurVersion);
1686     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1687   }
1688
1689   // Analyze the module, enumerating globals, functions, etc.
1690   ValueEnumerator VE(M);
1691
1692   // Emit blockinfo, which defines the standard abbreviations etc.
1693   WriteBlockInfo(VE, Stream);
1694
1695   // Emit information about parameter attributes.
1696   WriteAttributeTable(VE, Stream);
1697
1698   // Emit information describing all of the types in the module.
1699   WriteTypeTable(VE, Stream);
1700
1701   // Emit top-level description of module, including target triple, inline asm,
1702   // descriptors for global variables, and function prototype info.
1703   WriteModuleInfo(M, VE, Stream);
1704
1705   // Emit constants.
1706   WriteModuleConstants(VE, Stream);
1707
1708   // Emit metadata.
1709   WriteModuleMetadata(M, VE, Stream);
1710
1711   // Emit function bodies.
1712   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
1713     if (!F->isDeclaration())
1714       WriteFunction(*F, VE, Stream);
1715
1716   // Emit metadata.
1717   WriteModuleMetadataStore(M, Stream);
1718
1719   // Emit names for globals/functions etc.
1720   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1721
1722   // Emit use-lists.
1723   if (EnablePreserveUseListOrdering)
1724     WriteModuleUseLists(M, VE, Stream);
1725
1726   Stream.ExitBlock();
1727 }
1728
1729 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1730 /// header and trailer to make it compatible with the system archiver.  To do
1731 /// this we emit the following header, and then emit a trailer that pads the
1732 /// file out to be a multiple of 16 bytes.
1733 ///
1734 /// struct bc_header {
1735 ///   uint32_t Magic;         // 0x0B17C0DE
1736 ///   uint32_t Version;       // Version, currently always 0.
1737 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1738 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1739 ///   uint32_t CPUType;       // CPU specifier.
1740 ///   ... potentially more later ...
1741 /// };
1742 enum {
1743   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1744   DarwinBCHeaderSize = 5*4
1745 };
1746
1747 static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
1748   unsigned CPUType = ~0U;
1749
1750   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
1751   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
1752   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
1753   // specific constants here because they are implicitly part of the Darwin ABI.
1754   enum {
1755     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1756     DARWIN_CPU_TYPE_X86        = 7,
1757     DARWIN_CPU_TYPE_ARM        = 12,
1758     DARWIN_CPU_TYPE_POWERPC    = 18
1759   };
1760
1761   Triple::ArchType Arch = TT.getArch();
1762   if (Arch == Triple::x86_64)
1763     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1764   else if (Arch == Triple::x86)
1765     CPUType = DARWIN_CPU_TYPE_X86;
1766   else if (Arch == Triple::ppc)
1767     CPUType = DARWIN_CPU_TYPE_POWERPC;
1768   else if (Arch == Triple::ppc64)
1769     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1770   else if (Arch == Triple::arm || Arch == Triple::thumb)
1771     CPUType = DARWIN_CPU_TYPE_ARM;
1772
1773   // Traditional Bitcode starts after header.
1774   unsigned BCOffset = DarwinBCHeaderSize;
1775
1776   Stream.Emit(0x0B17C0DE, 32);
1777   Stream.Emit(0         , 32);  // Version.
1778   Stream.Emit(BCOffset  , 32);
1779   Stream.Emit(0         , 32);  // Filled in later.
1780   Stream.Emit(CPUType   , 32);
1781 }
1782
1783 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1784 /// finalize the header.
1785 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1786   // Update the size field in the header.
1787   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1788
1789   // If the file is not a multiple of 16 bytes, insert dummy padding.
1790   while (BufferSize & 15) {
1791     Stream.Emit(0, 8);
1792     ++BufferSize;
1793   }
1794 }
1795
1796
1797 /// WriteBitcodeToFile - Write the specified module to the specified output
1798 /// stream.
1799 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1800   std::vector<unsigned char> Buffer;
1801   BitstreamWriter Stream(Buffer);
1802
1803   Buffer.reserve(256*1024);
1804
1805   WriteBitcodeToStream( M, Stream );
1806
1807   // Write the generated bitstream to "Out".
1808   Out.write((char*)&Buffer.front(), Buffer.size());
1809 }
1810
1811 /// WriteBitcodeToStream - Write the specified module to the specified output
1812 /// stream.
1813 void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
1814   // If this is darwin or another generic macho target, emit a file header and
1815   // trailer if needed.
1816   Triple TT(M->getTargetTriple());
1817   if (TT.isOSDarwin())
1818     EmitDarwinBCHeader(Stream, TT);
1819
1820   // Emit the file header.
1821   Stream.Emit((unsigned)'B', 8);
1822   Stream.Emit((unsigned)'C', 8);
1823   Stream.Emit(0x0, 4);
1824   Stream.Emit(0xC, 4);
1825   Stream.Emit(0xE, 4);
1826   Stream.Emit(0xD, 4);
1827
1828   // Emit the module.
1829   WriteModule(M, Stream);
1830
1831   if (TT.isOSDarwin())
1832     EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
1833 }