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