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/TypeSymbolTable.h"
  24 #include "llvm/ValueSymbolTable.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Streams.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include "llvm/System/Program.h"
  29 using namespace llvm;
  30
  31 /// These are manifest constants used by the bitcode writer. They do not need to
  32 /// be kept in sync with the reader, but need to be consistent within this file.
  33 enum {
  34   CurVersion = 0,
  35
  36   // VALUE_SYMTAB_BLOCK abbrev id's.
  37   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  38   VST_ENTRY_7_ABBREV,
  39   VST_ENTRY_6_ABBREV,
  40   VST_BBENTRY_6_ABBREV,
  41
  42   // CONSTANTS_BLOCK abbrev id's.
  43   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  44   CONSTANTS_INTEGER_ABBREV,
  45   CONSTANTS_CE_CAST_Abbrev,
  46   CONSTANTS_NULL_Abbrev,
  47
  48   // FUNCTION_BLOCK abbrev id's.
  49   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
  50   FUNCTION_INST_BINOP_ABBREV,
  51   FUNCTION_INST_CAST_ABBREV,
  52   FUNCTION_INST_RET_VOID_ABBREV,
  53   FUNCTION_INST_RET_VAL_ABBREV,
  54   FUNCTION_INST_UNREACHABLE_ABBREV
  55 };
  56
  57
  58 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
  59   switch (Opcode) {
  60   default: assert(0 && "Unknown cast instruction!");
  61   case Instruction::Trunc   : return bitc::CAST_TRUNC;
  62   case Instruction::ZExt    : return bitc::CAST_ZEXT;
  63   case Instruction::SExt    : return bitc::CAST_SEXT;
  64   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
  65   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
  66   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
  67   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
  68   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
  69   case Instruction::FPExt   : return bitc::CAST_FPEXT;
  70   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
  71   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
  72   case Instruction::BitCast : return bitc::CAST_BITCAST;
  73   }
  74 }
  75
  76 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
  77   switch (Opcode) {
  78   default: assert(0 && "Unknown binary instruction!");
  79   case Instruction::Add:  return bitc::BINOP_ADD;
  80   case Instruction::Sub:  return bitc::BINOP_SUB;
  81   case Instruction::Mul:  return bitc::BINOP_MUL;
  82   case Instruction::UDiv: return bitc::BINOP_UDIV;
  83   case Instruction::FDiv:
  84   case Instruction::SDiv: return bitc::BINOP_SDIV;
  85   case Instruction::URem: return bitc::BINOP_UREM;
  86   case Instruction::FRem:
  87   case Instruction::SRem: return bitc::BINOP_SREM;
  88   case Instruction::Shl:  return bitc::BINOP_SHL;
  89   case Instruction::LShr: return bitc::BINOP_LSHR;
  90   case Instruction::AShr: return bitc::BINOP_ASHR;
  91   case Instruction::And:  return bitc::BINOP_AND;
  92   case Instruction::Or:   return bitc::BINOP_OR;
  93   case Instruction::Xor:  return bitc::BINOP_XOR;
  94   }
  95 }
  96
  97
  98
  99 static void WriteStringRecord(unsigned Code, const std::string &Str,
 100                               unsigned AbbrevToUse, BitstreamWriter &Stream) {
 101   SmallVector<unsigned, 64> Vals;
 102
 103   // Code: [strchar x N]
 104   for (unsigned i = 0, e = Str.size(); i != e; ++i)
 105     Vals.push_back(Str[i]);
 106
 107   // Emit the finished record.
 108   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 109 }
 110
 111 // Emit information about parameter attributes.
 112 static void WriteAttributeTable(const ValueEnumerator &VE,
 113                                 BitstreamWriter &Stream) {
 114   const std::vector<AttrListPtr> &Attrs = VE.getAttributes();
 115   if (Attrs.empty()) return;
 116
 117   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 118
 119   SmallVector<uint64_t, 64> Record;
 120   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
 121     const AttrListPtr &A = Attrs[i];
 122     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
 123       const AttributeWithIndex &PAWI = A.getSlot(i);
 124       Record.push_back(PAWI.Index);
 125       Record.push_back(PAWI.Attrs);
 126     }
 127
 128     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
 129     Record.clear();
 130   }
 131
 132   Stream.ExitBlock();
 133 }
 134
 135 /// WriteTypeTable - Write out the type table for a module.
 136 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 137   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
 138
 139   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
 140   SmallVector<uint64_t, 64> TypeVals;
 141
 142   // Abbrev for TYPE_CODE_POINTER.
 143   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 144   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
 145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 146                             Log2_32_Ceil(VE.getTypes().size()+1)));
 147   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
 148   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 149
 150   // Abbrev for TYPE_CODE_FUNCTION.
 151   Abbv = new BitCodeAbbrev();
 152   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
 153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
 154   Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
 155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 157                             Log2_32_Ceil(VE.getTypes().size()+1)));
 158   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 159
 160   // Abbrev for TYPE_CODE_STRUCT.
 161   Abbv = new BitCodeAbbrev();
 162   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT));
 163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
 164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 166                             Log2_32_Ceil(VE.getTypes().size()+1)));
 167   unsigned StructAbbrev = Stream.EmitAbbrev(Abbv);
 168
 169   // Abbrev for TYPE_CODE_ARRAY.
 170   Abbv = new BitCodeAbbrev();
 171   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
 172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
 173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 174                             Log2_32_Ceil(VE.getTypes().size()+1)));
 175   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 176
 177   // Emit an entry count so the reader can reserve space.
 178   TypeVals.push_back(TypeList.size());
 179   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
 180   TypeVals.clear();
 181
 182   // Loop over all of the types, emitting each in turn.
 183   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
 184     const Type *T = TypeList[i].first;
 185     int AbbrevToUse = 0;
 186     unsigned Code = 0;
 187
 188     switch (T->getTypeID()) {
 189     default: assert(0 && "Unknown type!");
 190     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
 191     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
 192     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
 193     case Type::X86_FP80TyID: Code = bitc::TYPE_CODE_X86_FP80; break;
 194     case Type::FP128TyID: Code = bitc::TYPE_CODE_FP128; break;
 195     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
 196     case Type::LabelTyID:  Code = bitc::TYPE_CODE_LABEL;  break;
 197     case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
 198     case Type::IntegerTyID:
 199       // INTEGER: [width]
 200       Code = bitc::TYPE_CODE_INTEGER;
 201       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
 202       break;
 203     case Type::PointerTyID: {
 204       const PointerType *PTy = cast<PointerType>(T);
 205       // POINTER: [pointee type, address space]
 206       Code = bitc::TYPE_CODE_POINTER;
 207       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
 208       unsigned AddressSpace = PTy->getAddressSpace();
 209       TypeVals.push_back(AddressSpace);
 210       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
 211       break;
 212     }
 213     case Type::FunctionTyID: {
 214       const FunctionType *FT = cast<FunctionType>(T);
 215       // FUNCTION: [isvararg, attrid, retty, paramty x N]
 216       Code = bitc::TYPE_CODE_FUNCTION;
 217       TypeVals.push_back(FT->isVarArg());
 218       TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
 219       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
 220       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
 221         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
 222       AbbrevToUse = FunctionAbbrev;
 223       break;
 224     }
 225     case Type::StructTyID: {
 226       const StructType *ST = cast<StructType>(T);
 227       // STRUCT: [ispacked, eltty x N]
 228       Code = bitc::TYPE_CODE_STRUCT;
 229       TypeVals.push_back(ST->isPacked());
 230       // Output all of the element types.
 231       for (StructType::element_iterator I = ST->element_begin(),
 232            E = ST->element_end(); I != E; ++I)
 233         TypeVals.push_back(VE.getTypeID(*I));
 234       AbbrevToUse = StructAbbrev;
 235       break;
 236     }
 237     case Type::ArrayTyID: {
 238       const ArrayType *AT = cast<ArrayType>(T);
 239       // ARRAY: [numelts, eltty]
 240       Code = bitc::TYPE_CODE_ARRAY;
 241       TypeVals.push_back(AT->getNumElements());
 242       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
 243       AbbrevToUse = ArrayAbbrev;
 244       break;
 245     }
 246     case Type::VectorTyID: {
 247       const VectorType *VT = cast<VectorType>(T);
 248       // VECTOR [numelts, eltty]
 249       Code = bitc::TYPE_CODE_VECTOR;
 250       TypeVals.push_back(VT->getNumElements());
 251       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
 252       break;
 253     }
 254     }
 255
 256     // Emit the finished record.
 257     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
 258     TypeVals.clear();
 259   }
 260
 261   Stream.ExitBlock();
 262 }
 263
 264 static unsigned getEncodedLinkage(const GlobalValue *GV) {
 265   switch (GV->getLinkage()) {
 266   default: assert(0 && "Invalid linkage!");
 267   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
 268   case GlobalValue::ExternalLinkage:     return 0;
 269   case GlobalValue::WeakLinkage:         return 1;
 270   case GlobalValue::AppendingLinkage:    return 2;
 271   case GlobalValue::InternalLinkage:     return 3;
 272   case GlobalValue::LinkOnceLinkage:     return 4;
 273   case GlobalValue::DLLImportLinkage:    return 5;
 274   case GlobalValue::DLLExportLinkage:    return 6;
 275   case GlobalValue::ExternalWeakLinkage: return 7;
 276   case GlobalValue::CommonLinkage:       return 8;
 277   }
 278 }
 279
 280 static unsigned getEncodedVisibility(const GlobalValue *GV) {
 281   switch (GV->getVisibility()) {
 282   default: assert(0 && "Invalid visibility!");
 283   case GlobalValue::DefaultVisibility:   return 0;
 284   case GlobalValue::HiddenVisibility:    return 1;
 285   case GlobalValue::ProtectedVisibility: return 2;
 286   }
 287 }
 288
 289 // Emit top-level description of module, including target triple, inline asm,
 290 // descriptors for global variables, and function prototype info.
 291 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 292                             BitstreamWriter &Stream) {
 293   // Emit the list of dependent libraries for the Module.
 294   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
 295     WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
 296
 297   // Emit various pieces of data attached to a module.
 298   if (!M->getTargetTriple().empty())
 299     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
 300                       0/*TODO*/, Stream);
 301   if (!M->getDataLayout().empty())
 302     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
 303                       0/*TODO*/, Stream);
 304   if (!M->getModuleInlineAsm().empty())
 305     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
 306                       0/*TODO*/, Stream);
 307
 308   // Emit information about sections and GC, computing how many there are. Also
 309   // compute the maximum alignment value.
 310   std::map<std::string, unsigned> SectionMap;
 311   std::map<std::string, unsigned> GCMap;
 312   unsigned MaxAlignment = 0;
 313   unsigned MaxGlobalType = 0;
 314   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 315        GV != E; ++GV) {
 316     MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
 317     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
 318
 319     if (!GV->hasSection()) continue;
 320     // Give section names unique ID's.
 321     unsigned &Entry = SectionMap[GV->getSection()];
 322     if (Entry != 0) continue;
 323     WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
 324                       0/*TODO*/, Stream);
 325     Entry = SectionMap.size();
 326   }
 327   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 328     MaxAlignment = std::max(MaxAlignment, F->getAlignment());
 329     if (F->hasSection()) {
 330       // Give section names unique ID's.
 331       unsigned &Entry = SectionMap[F->getSection()];
 332       if (!Entry) {
 333         WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
 334                           0/*TODO*/, Stream);
 335         Entry = SectionMap.size();
 336       }
 337     }
 338     if (F->hasGC()) {
 339       // Same for GC names.
 340       unsigned &Entry = GCMap[F->getGC()];
 341       if (!Entry) {
 342         WriteStringRecord(bitc::MODULE_CODE_GCNAME, F->getGC(),
 343                           0/*TODO*/, Stream);
 344         Entry = GCMap.size();
 345       }
 346     }
 347   }
 348
 349   // Emit abbrev for globals, now that we know # sections and max alignment.
 350   unsigned SimpleGVarAbbrev = 0;
 351   if (!M->global_empty()) {
 352     // Add an abbrev for common globals with no visibility or thread localness.
 353     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 354     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
 355     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 356                               Log2_32_Ceil(MaxGlobalType+1)));
 357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
 358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
 359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));      // Linkage.
 360     if (MaxAlignment == 0)                                      // Alignment.
 361       Abbv->Add(BitCodeAbbrevOp(0));
 362     else {
 363       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
 364       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 365                                Log2_32_Ceil(MaxEncAlignment+1)));
 366     }
 367     if (SectionMap.empty())                                    // Section.
 368       Abbv->Add(BitCodeAbbrevOp(0));
 369     else
 370       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
 371                                Log2_32_Ceil(SectionMap.size()+1)));
 372     // Don't bother emitting vis + thread local.
 373     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
 374   }
 375
 376   // Emit the global variable information.
 377   SmallVector<unsigned, 64> Vals;
 378   for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
 379        GV != E; ++GV) {
 380     unsigned AbbrevToUse = 0;
 381
 382     // GLOBALVAR: [type, isconst, initid,
 383     //             linkage, alignment, section, visibility, threadlocal]
 384     Vals.push_back(VE.getTypeID(GV->getType()));
 385     Vals.push_back(GV->isConstant());
 386     Vals.push_back(GV->isDeclaration() ? 0 :
 387                    (VE.getValueID(GV->getInitializer()) + 1));
 388     Vals.push_back(getEncodedLinkage(GV));
 389     Vals.push_back(Log2_32(GV->getAlignment())+1);
 390     Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
 391     if (GV->isThreadLocal() ||
 392         GV->getVisibility() != GlobalValue::DefaultVisibility) {
 393       Vals.push_back(getEncodedVisibility(GV));
 394       Vals.push_back(GV->isThreadLocal());
 395     } else {
 396       AbbrevToUse = SimpleGVarAbbrev;
 397     }
 398
 399     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
 400     Vals.clear();
 401   }
 402
 403   // Emit the function proto information.
 404   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
 405     // FUNCTION:  [type, callingconv, isproto, paramattr,
 406     //             linkage, alignment, section, visibility, gc]
 407     Vals.push_back(VE.getTypeID(F->getType()));
 408     Vals.push_back(F->getCallingConv());
 409     Vals.push_back(F->isDeclaration());
 410     Vals.push_back(getEncodedLinkage(F));
 411     Vals.push_back(VE.getAttributeID(F->getAttributes()));
 412     Vals.push_back(Log2_32(F->getAlignment())+1);
 413     Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
 414     Vals.push_back(getEncodedVisibility(F));
 415     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
 416
 417     unsigned AbbrevToUse = 0;
 418     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
 419     Vals.clear();
 420   }
 421
 422
 423   // Emit the alias information.
 424   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
 425        AI != E; ++AI) {
 426     Vals.push_back(VE.getTypeID(AI->getType()));
 427     Vals.push_back(VE.getValueID(AI->getAliasee()));
 428     Vals.push_back(getEncodedLinkage(AI));
 429     Vals.push_back(getEncodedVisibility(AI));
 430     unsigned AbbrevToUse = 0;
 431     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
 432     Vals.clear();
 433   }
 434 }
 435
 436
 437 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
 438                            const ValueEnumerator &VE,
 439                            BitstreamWriter &Stream, bool isGlobal) {
 440   if (FirstVal == LastVal) return;
 441
 442   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 443
 444   unsigned AggregateAbbrev = 0;
 445   unsigned String8Abbrev = 0;
 446   unsigned CString7Abbrev = 0;
 447   unsigned CString6Abbrev = 0;
 448   // If this is a constant pool for the module, emit module-specific abbrevs.
 449   if (isGlobal) {
 450     // Abbrev for CST_CODE_AGGREGATE.
 451     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
 452     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
 453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
 455     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
 456
 457     // Abbrev for CST_CODE_STRING.
 458     Abbv = new BitCodeAbbrev();
 459     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
 460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
 462     String8Abbrev = Stream.EmitAbbrev(Abbv);
 463     // Abbrev for CST_CODE_CSTRING.
 464     Abbv = new BitCodeAbbrev();
 465     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
 468     CString7Abbrev = Stream.EmitAbbrev(Abbv);
 469     // Abbrev for CST_CODE_CSTRING.
 470     Abbv = new BitCodeAbbrev();
 471     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
 472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
 473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
 474     CString6Abbrev = Stream.EmitAbbrev(Abbv);
 475   }
 476
 477   SmallVector<uint64_t, 64> Record;
 478
 479   const ValueEnumerator::ValueList &Vals = VE.getValues();
 480   const Type *LastTy = 0;
 481   for (unsigned i = FirstVal; i != LastVal; ++i) {
 482     const Value *V = Vals[i].first;
 483     // If we need to switch types, do so now.
 484     if (V->getType() != LastTy) {
 485       LastTy = V->getType();
 486       Record.push_back(VE.getTypeID(LastTy));
 487       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
 488                         CONSTANTS_SETTYPE_ABBREV);
 489       Record.clear();
 490     }
 491
 492     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
 493       Record.push_back(unsigned(IA->hasSideEffects()));
 494
 495       // Add the asm string.
 496       const std::string &AsmStr = IA->getAsmString();
 497       Record.push_back(AsmStr.size());
 498       for (unsigned i = 0, e = AsmStr.size(); i != e; ++i)
 499         Record.push_back(AsmStr[i]);
 500
 501       // Add the constraint string.
 502       const std::string &ConstraintStr = IA->getConstraintString();
 503       Record.push_back(ConstraintStr.size());
 504       for (unsigned i = 0, e = ConstraintStr.size(); i != e; ++i)
 505         Record.push_back(ConstraintStr[i]);
 506       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
 507       Record.clear();
 508       continue;
 509     }
 510     const Constant *C = cast<Constant>(V);
 511     unsigned Code = -1U;
 512     unsigned AbbrevToUse = 0;
 513     if (C->isNullValue()) {
 514       Code = bitc::CST_CODE_NULL;
 515     } else if (isa<UndefValue>(C)) {
 516       Code = bitc::CST_CODE_UNDEF;
 517     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
 518       if (IV->getBitWidth() <= 64) {
 519         int64_t V = IV->getSExtValue();
 520         if (V >= 0)
 521           Record.push_back(V << 1);
 522         else
 523           Record.push_back((-V << 1) | 1);
 524         Code = bitc::CST_CODE_INTEGER;
 525         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
 526       } else {                             // Wide integers, > 64 bits in size.
 527         // We have an arbitrary precision integer value to write whose
 528         // bit width is > 64. However, in canonical unsigned integer
 529         // format it is likely that the high bits are going to be zero.
 530         // So, we only write the number of active words.
 531         unsigned NWords = IV->getValue().getActiveWords();
 532         const uint64_t *RawWords = IV->getValue().getRawData();
 533         for (unsigned i = 0; i != NWords; ++i) {
 534           int64_t V = RawWords[i];
 535           if (V >= 0)
 536             Record.push_back(V << 1);
 537           else
 538             Record.push_back((-V << 1) | 1);
 539         }
 540         Code = bitc::CST_CODE_WIDE_INTEGER;
 541       }
 542     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 543       Code = bitc::CST_CODE_FLOAT;
 544       const Type *Ty = CFP->getType();
 545       if (Ty == Type::FloatTy || Ty == Type::DoubleTy) {
 546         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
 547       } else if (Ty == Type::X86_FP80Ty) {
 548         // api needed to prevent premature destruction
 549         APInt api = CFP->getValueAPF().bitcastToAPInt();
 550         const uint64_t *p = api.getRawData();
 551         Record.push_back(p[0]);
 552         Record.push_back((uint16_t)p[1]);
 553       } else if (Ty == Type::FP128Ty || Ty == Type::PPC_FP128Ty) {
 554         APInt api = CFP->getValueAPF().bitcastToAPInt();
 555         const uint64_t *p = api.getRawData();
 556         Record.push_back(p[0]);
 557         Record.push_back(p[1]);
 558       } else {
 559         assert (0 && "Unknown FP type!");
 560       }
 561     } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
 562       // Emit constant strings specially.
 563       unsigned NumOps = C->getNumOperands();
 564       // If this is a null-terminated string, use the denser CSTRING encoding.
 565       if (C->getOperand(NumOps-1)->isNullValue()) {
 566         Code = bitc::CST_CODE_CSTRING;
 567         --NumOps;  // Don't encode the null, which isn't allowed by char6.
 568       } else {
 569         Code = bitc::CST_CODE_STRING;
 570         AbbrevToUse = String8Abbrev;
 571       }
 572       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
 573       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
 574       for (unsigned i = 0; i != NumOps; ++i) {
 575         unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
 576         Record.push_back(V);
 577         isCStr7 &= (V & 128) == 0;
 578         if (isCStrChar6)
 579           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
 580       }
 581
 582       if (isCStrChar6)
 583         AbbrevToUse = CString6Abbrev;
 584       else if (isCStr7)
 585         AbbrevToUse = CString7Abbrev;
 586     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
 587                isa<ConstantVector>(V)) {
 588       Code = bitc::CST_CODE_AGGREGATE;
 589       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
 590         Record.push_back(VE.getValueID(C->getOperand(i)));
 591       AbbrevToUse = AggregateAbbrev;
 592     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
 593       switch (CE->getOpcode()) {
 594       default:
 595         if (Instruction::isCast(CE->getOpcode())) {
 596           Code = bitc::CST_CODE_CE_CAST;
 597           Record.push_back(GetEncodedCastOpcode(CE->getOpcode()));
 598           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 599           Record.push_back(VE.getValueID(C->getOperand(0)));
 600           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
 601         } else {
 602           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
 603           Code = bitc::CST_CODE_CE_BINOP;
 604           Record.push_back(GetEncodedBinaryOpcode(CE->getOpcode()));
 605           Record.push_back(VE.getValueID(C->getOperand(0)));
 606           Record.push_back(VE.getValueID(C->getOperand(1)));
 607         }
 608         break;
 609       case Instruction::GetElementPtr:
 610         Code = bitc::CST_CODE_CE_GEP;
 611         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
 612           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
 613           Record.push_back(VE.getValueID(C->getOperand(i)));
 614         }
 615         break;
 616       case Instruction::Select:
 617         Code = bitc::CST_CODE_CE_SELECT;
 618         Record.push_back(VE.getValueID(C->getOperand(0)));
 619         Record.push_back(VE.getValueID(C->getOperand(1)));
 620         Record.push_back(VE.getValueID(C->getOperand(2)));
 621         break;
 622       case Instruction::ExtractElement:
 623         Code = bitc::CST_CODE_CE_EXTRACTELT;
 624         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 625         Record.push_back(VE.getValueID(C->getOperand(0)));
 626         Record.push_back(VE.getValueID(C->getOperand(1)));
 627         break;
 628       case Instruction::InsertElement:
 629         Code = bitc::CST_CODE_CE_INSERTELT;
 630         Record.push_back(VE.getValueID(C->getOperand(0)));
 631         Record.push_back(VE.getValueID(C->getOperand(1)));
 632         Record.push_back(VE.getValueID(C->getOperand(2)));
 633         break;
 634       case Instruction::ShuffleVector:
 635         Code = bitc::CST_CODE_CE_SHUFFLEVEC;
 636         Record.push_back(VE.getValueID(C->getOperand(0)));
 637         Record.push_back(VE.getValueID(C->getOperand(1)));
 638         Record.push_back(VE.getValueID(C->getOperand(2)));
 639         break;
 640       case Instruction::ICmp:
 641       case Instruction::FCmp:
 642       case Instruction::VICmp:
 643       case Instruction::VFCmp:
 644         if (isa<VectorType>(C->getOperand(0)->getType())
 645             && (CE->getOpcode() == Instruction::ICmp
 646                 || CE->getOpcode() == Instruction::FCmp)) {
 647           // compare returning vector of Int1Ty
 648           assert(0 && "Unsupported constant!");
 649         } else {
 650           Code = bitc::CST_CODE_CE_CMP;
 651         }
 652         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
 653         Record.push_back(VE.getValueID(C->getOperand(0)));
 654         Record.push_back(VE.getValueID(C->getOperand(1)));
 655         Record.push_back(CE->getPredicate());
 656         break;
 657       }
 658     } else {
 659       assert(0 && "Unknown constant!");
 660     }
 661     Stream.EmitRecord(Code, Record, AbbrevToUse);
 662     Record.clear();
 663   }
 664
 665   Stream.ExitBlock();
 666 }
 667
 668 static void WriteModuleConstants(const ValueEnumerator &VE,
 669                                  BitstreamWriter &Stream) {
 670   const ValueEnumerator::ValueList &Vals = VE.getValues();
 671
 672   // Find the first constant to emit, which is the first non-globalvalue value.
 673   // We know globalvalues have been emitted by WriteModuleInfo.
 674   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 675     if (!isa<GlobalValue>(Vals[i].first)) {
 676       WriteConstants(i, Vals.size(), VE, Stream, true);
 677       return;
 678     }
 679   }
 680 }
 681
 682 /// PushValueAndType - The file has to encode both the value and type id for
 683 /// many values, because we need to know what type to create for forward
 684 /// references.  However, most operands are not forward references, so this type
 685 /// field is not needed.
 686 ///
 687 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 688 /// instruction ID, then it is a forward reference, and it also includes the
 689 /// type ID.
 690 static bool PushValueAndType(Value *V, unsigned InstID,
 691                              SmallVector<unsigned, 64> &Vals,
 692                              ValueEnumerator &VE) {
 693   unsigned ValID = VE.getValueID(V);
 694   Vals.push_back(ValID);
 695   if (ValID >= InstID) {
 696     Vals.push_back(VE.getTypeID(V->getType()));
 697     return true;
 698   }
 699   return false;
 700 }
 701
 702 /// WriteInstruction - Emit an instruction to the specified stream.
 703 static void WriteInstruction(const Instruction &I, unsigned InstID,
 704                              ValueEnumerator &VE, BitstreamWriter &Stream,
 705                              SmallVector<unsigned, 64> &Vals) {
 706   unsigned Code = 0;
 707   unsigned AbbrevToUse = 0;
 708   switch (I.getOpcode()) {
 709   default:
 710     if (Instruction::isCast(I.getOpcode())) {
 711       Code = bitc::FUNC_CODE_INST_CAST;
 712       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 713         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
 714       Vals.push_back(VE.getTypeID(I.getType()));
 715       Vals.push_back(GetEncodedCastOpcode(I.getOpcode()));
 716     } else {
 717       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
 718       Code = bitc::FUNC_CODE_INST_BINOP;
 719       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 720         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
 721       Vals.push_back(VE.getValueID(I.getOperand(1)));
 722       Vals.push_back(GetEncodedBinaryOpcode(I.getOpcode()));
 723     }
 724     break;
 725
 726   case Instruction::GetElementPtr:
 727     Code = bitc::FUNC_CODE_INST_GEP;
 728     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 729       PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 730     break;
 731   case Instruction::ExtractValue: {
 732     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
 733     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 734     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
 735     for (const unsigned *i = EVI->idx_begin(), *e = EVI->idx_end(); i != e; ++i)
 736       Vals.push_back(*i);
 737     break;
 738   }
 739   case Instruction::InsertValue: {
 740     Code = bitc::FUNC_CODE_INST_INSERTVAL;
 741     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 742     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 743     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
 744     for (const unsigned *i = IVI->idx_begin(), *e = IVI->idx_end(); i != e; ++i)
 745       Vals.push_back(*i);
 746     break;
 747   }
 748   case Instruction::Select:
 749     Code = bitc::FUNC_CODE_INST_VSELECT;
 750     PushValueAndType(I.getOperand(1), InstID, Vals, VE);
 751     Vals.push_back(VE.getValueID(I.getOperand(2)));
 752     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 753     break;
 754   case Instruction::ExtractElement:
 755     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
 756     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 757     Vals.push_back(VE.getValueID(I.getOperand(1)));
 758     break;
 759   case Instruction::InsertElement:
 760     Code = bitc::FUNC_CODE_INST_INSERTELT;
 761     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 762     Vals.push_back(VE.getValueID(I.getOperand(1)));
 763     Vals.push_back(VE.getValueID(I.getOperand(2)));
 764     break;
 765   case Instruction::ShuffleVector:
 766     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
 767     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 768     Vals.push_back(VE.getValueID(I.getOperand(1)));
 769     Vals.push_back(VE.getValueID(I.getOperand(2)));
 770     break;
 771   case Instruction::ICmp:
 772   case Instruction::FCmp:
 773   case Instruction::VICmp:
 774   case Instruction::VFCmp:
 775     if (I.getOpcode() == Instruction::ICmp
 776         || I.getOpcode() == Instruction::FCmp) {
 777       // compare returning Int1Ty or vector of Int1Ty
 778       Code = bitc::FUNC_CODE_INST_CMP2;
 779     } else {
 780       Code = bitc::FUNC_CODE_INST_CMP;
 781     }
 782     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 783     Vals.push_back(VE.getValueID(I.getOperand(1)));
 784     Vals.push_back(cast<CmpInst>(I).getPredicate());
 785     break;
 786
 787   case Instruction::Ret:
 788     {
 789       Code = bitc::FUNC_CODE_INST_RET;
 790       unsigned NumOperands = I.getNumOperands();
 791       if (NumOperands == 0)
 792         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
 793       else if (NumOperands == 1) {
 794         if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
 795           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
 796       } else {
 797         for (unsigned i = 0, e = NumOperands; i != e; ++i)
 798           PushValueAndType(I.getOperand(i), InstID, Vals, VE);
 799       }
 800     }
 801     break;
 802   case Instruction::Br:
 803     Code = bitc::FUNC_CODE_INST_BR;
 804     Vals.push_back(VE.getValueID(I.getOperand(0)));
 805     if (cast<BranchInst>(I).isConditional()) {
 806       Vals.push_back(VE.getValueID(I.getOperand(1)));
 807       Vals.push_back(VE.getValueID(I.getOperand(2)));
 808     }
 809     break;
 810   case Instruction::Switch:
 811     Code = bitc::FUNC_CODE_INST_SWITCH;
 812     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
 813     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 814       Vals.push_back(VE.getValueID(I.getOperand(i)));
 815     break;
 816   case Instruction::Invoke: {
 817     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 818     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 819     Code = bitc::FUNC_CODE_INST_INVOKE;
 820
 821     const InvokeInst *II = cast<InvokeInst>(&I);
 822     Vals.push_back(VE.getAttributeID(II->getAttributes()));
 823     Vals.push_back(II->getCallingConv());
 824     Vals.push_back(VE.getValueID(I.getOperand(1)));      // normal dest
 825     Vals.push_back(VE.getValueID(I.getOperand(2)));      // unwind dest
 826     PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
 827
 828     // Emit value #'s for the fixed parameters.
 829     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 830       Vals.push_back(VE.getValueID(I.getOperand(i+3)));  // fixed param.
 831
 832     // Emit type/value pairs for varargs params.
 833     if (FTy->isVarArg()) {
 834       for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
 835            i != e; ++i)
 836         PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
 837     }
 838     break;
 839   }
 840   case Instruction::Unwind:
 841     Code = bitc::FUNC_CODE_INST_UNWIND;
 842     break;
 843   case Instruction::Unreachable:
 844     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
 845     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
 846     break;
 847
 848   case Instruction::PHI:
 849     Code = bitc::FUNC_CODE_INST_PHI;
 850     Vals.push_back(VE.getTypeID(I.getType()));
 851     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
 852       Vals.push_back(VE.getValueID(I.getOperand(i)));
 853     break;
 854
 855   case Instruction::Malloc:
 856     Code = bitc::FUNC_CODE_INST_MALLOC;
 857     Vals.push_back(VE.getTypeID(I.getType()));
 858     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 859     Vals.push_back(Log2_32(cast<MallocInst>(I).getAlignment())+1);
 860     break;
 861
 862   case Instruction::Free:
 863     Code = bitc::FUNC_CODE_INST_FREE;
 864     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
 865     break;
 866
 867   case Instruction::Alloca:
 868     Code = bitc::FUNC_CODE_INST_ALLOCA;
 869     Vals.push_back(VE.getTypeID(I.getType()));
 870     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
 871     Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
 872     break;
 873
 874   case Instruction::Load:
 875     Code = bitc::FUNC_CODE_INST_LOAD;
 876     if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))  // ptr
 877       AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
 878
 879     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
 880     Vals.push_back(cast<LoadInst>(I).isVolatile());
 881     break;
 882   case Instruction::Store:
 883     Code = bitc::FUNC_CODE_INST_STORE2;
 884     PushValueAndType(I.getOperand(1), InstID, Vals, VE);  // ptrty + ptr
 885     Vals.push_back(VE.getValueID(I.getOperand(0)));       // val.
 886     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
 887     Vals.push_back(cast<StoreInst>(I).isVolatile());
 888     break;
 889   case Instruction::Call: {
 890     const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
 891     const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
 892
 893     Code = bitc::FUNC_CODE_INST_CALL;
 894
 895     const CallInst *CI = cast<CallInst>(&I);
 896     Vals.push_back(VE.getAttributeID(CI->getAttributes()));
 897     Vals.push_back((CI->getCallingConv() << 1) | unsigned(CI->isTailCall()));
 898     PushValueAndType(CI->getOperand(0), InstID, Vals, VE);  // Callee
 899
 900     // Emit value #'s for the fixed parameters.
 901     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
 902       Vals.push_back(VE.getValueID(I.getOperand(i+1)));  // fixed param.
 903
 904     // Emit type/value pairs for varargs params.
 905     if (FTy->isVarArg()) {
 906       unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
 907       for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
 908            i != e; ++i)
 909         PushValueAndType(I.getOperand(i), InstID, Vals, VE);  // varargs
 910     }
 911     break;
 912   }
 913   case Instruction::VAArg:
 914     Code = bitc::FUNC_CODE_INST_VAARG;
 915     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
 916     Vals.push_back(VE.getValueID(I.getOperand(0))); // valist.
 917     Vals.push_back(VE.getTypeID(I.getType())); // restype.
 918     break;
 919   }
 920
 921   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 922   Vals.clear();
 923 }
 924
 925 // Emit names for globals/functions etc.
 926 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
 927                                   const ValueEnumerator &VE,
 928                                   BitstreamWriter &Stream) {
 929   if (VST.empty()) return;
 930   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 931
 932   // FIXME: Set up the abbrev, we know how many values there are!
 933   // FIXME: We know if the type names can use 7-bit ascii.
 934   SmallVector<unsigned, 64> NameVals;
 935
 936   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
 937        SI != SE; ++SI) {
 938
 939     const ValueName &Name = *SI;
 940
 941     // Figure out the encoding to use for the name.
 942     bool is7Bit = true;
 943     bool isChar6 = true;
 944     for (const char *C = Name.getKeyData(), *E = C+Name.getKeyLength();
 945          C != E; ++C) {
 946       if (isChar6)
 947         isChar6 = BitCodeAbbrevOp::isChar6(*C);
 948       if ((unsigned char)*C & 128) {
 949         is7Bit = false;
 950         break;  // don't bother scanning the rest.
 951       }
 952     }
 953
 954     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
 955
 956     // VST_ENTRY:   [valueid, namechar x N]
 957     // VST_BBENTRY: [bbid, namechar x N]
 958     unsigned Code;
 959     if (isa<BasicBlock>(SI->getValue())) {
 960       Code = bitc::VST_CODE_BBENTRY;
 961       if (isChar6)
 962         AbbrevToUse = VST_BBENTRY_6_ABBREV;
 963     } else {
 964       Code = bitc::VST_CODE_ENTRY;
 965       if (isChar6)
 966         AbbrevToUse = VST_ENTRY_6_ABBREV;
 967       else if (is7Bit)
 968         AbbrevToUse = VST_ENTRY_7_ABBREV;
 969     }
 970
 971     NameVals.push_back(VE.getValueID(SI->getValue()));
 972     for (const char *P = Name.getKeyData(),
 973          *E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
 974       NameVals.push_back((unsigned char)*P);
 975
 976     // Emit the finished record.
 977     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
 978     NameVals.clear();
 979   }
 980   Stream.ExitBlock();
 981 }
 982
 983 /// WriteFunction - Emit a function body to the module stream.
 984 static void WriteFunction(const Function &F, ValueEnumerator &VE,
 985                           BitstreamWriter &Stream) {
 986   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
 987   VE.incorporateFunction(F);
 988
 989   SmallVector<unsigned, 64> Vals;
 990
 991   // Emit the number of basic blocks, so the reader can create them ahead of
 992   // time.
 993   Vals.push_back(VE.getBasicBlocks().size());
 994   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
 995   Vals.clear();
 996
 997   // If there are function-local constants, emit them now.
 998   unsigned CstStart, CstEnd;
 999   VE.getFunctionConstantRange(CstStart, CstEnd);
1000   WriteConstants(CstStart, CstEnd, VE, Stream, false);
1001
1002   // Keep a running idea of what the instruction ID is.
1003   unsigned InstID = CstEnd;
1004
1005   // Finally, emit all the instructions, in order.
1006   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
1007     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
1008          I != E; ++I) {
1009       WriteInstruction(*I, InstID, VE, Stream, Vals);
1010       if (I->getType() != Type::VoidTy)
1011         ++InstID;
1012     }
1013
1014   // Emit names for all the instructions etc.
1015   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
1016
1017   VE.purgeFunction();
1018   Stream.ExitBlock();
1019 }
1020
1021 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
1022 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
1023                                  const ValueEnumerator &VE,
1024                                  BitstreamWriter &Stream) {
1025   if (TST.empty()) return;
1026
1027   Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
1028
1029   // 7-bit fixed width VST_CODE_ENTRY strings.
1030   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1031   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1033                             Log2_32_Ceil(VE.getTypes().size()+1)));
1034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1036   unsigned V7Abbrev = Stream.EmitAbbrev(Abbv);
1037
1038   SmallVector<unsigned, 64> NameVals;
1039
1040   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
1041        TI != TE; ++TI) {
1042     // TST_ENTRY: [typeid, namechar x N]
1043     NameVals.push_back(VE.getTypeID(TI->second));
1044
1045     const std::string &Str = TI->first;
1046     bool is7Bit = true;
1047     for (unsigned i = 0, e = Str.size(); i != e; ++i) {
1048       NameVals.push_back((unsigned char)Str[i]);
1049       if (Str[i] & 128)
1050         is7Bit = false;
1051     }
1052
1053     // Emit the finished record.
1054     Stream.EmitRecord(bitc::VST_CODE_ENTRY, NameVals, is7Bit ? V7Abbrev : 0);
1055     NameVals.clear();
1056   }
1057
1058   Stream.ExitBlock();
1059 }
1060
1061 // Emit blockinfo, which defines the standard abbreviations etc.
1062 static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
1063   // We only want to emit block info records for blocks that have multiple
1064   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.  Other
1065   // blocks can defined their abbrevs inline.
1066   Stream.EnterBlockInfoBlock(2);
1067
1068   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
1069     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1070     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
1071     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1072     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1073     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1074     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1075                                    Abbv) != VST_ENTRY_8_ABBREV)
1076       assert(0 && "Unexpected abbrev ordering!");
1077   }
1078
1079   { // 7-bit fixed width VST_ENTRY strings.
1080     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1081     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1082     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1083     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1084     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
1085     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1086                                    Abbv) != VST_ENTRY_7_ABBREV)
1087       assert(0 && "Unexpected abbrev ordering!");
1088   }
1089   { // 6-bit char6 VST_ENTRY strings.
1090     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1091     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
1092     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1093     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1094     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1095     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1096                                    Abbv) != VST_ENTRY_6_ABBREV)
1097       assert(0 && "Unexpected abbrev ordering!");
1098   }
1099   { // 6-bit char6 VST_BBENTRY strings.
1100     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1101     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
1102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1104     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1105     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
1106                                    Abbv) != VST_BBENTRY_6_ABBREV)
1107       assert(0 && "Unexpected abbrev ordering!");
1108   }
1109
1110
1111
1112   { // SETTYPE abbrev for CONSTANTS_BLOCK.
1113     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1114     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
1115     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1116                               Log2_32_Ceil(VE.getTypes().size()+1)));
1117     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1118                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
1119       assert(0 && "Unexpected abbrev ordering!");
1120   }
1121
1122   { // INTEGER abbrev for CONSTANTS_BLOCK.
1123     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1124     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
1125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1126     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1127                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
1128       assert(0 && "Unexpected abbrev ordering!");
1129   }
1130
1131   { // CE_CAST abbrev for CONSTANTS_BLOCK.
1132     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1133     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
1134     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
1135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
1136                               Log2_32_Ceil(VE.getTypes().size()+1)));
1137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
1138
1139     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1140                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
1141       assert(0 && "Unexpected abbrev ordering!");
1142   }
1143   { // NULL abbrev for CONSTANTS_BLOCK.
1144     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1145     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
1146     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
1147                                    Abbv) != CONSTANTS_NULL_Abbrev)
1148       assert(0 && "Unexpected abbrev ordering!");
1149   }
1150
1151   // FIXME: This should only use space for first class types!
1152
1153   { // INST_LOAD abbrev for FUNCTION_BLOCK.
1154     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1155     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
1156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
1157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
1159     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1160                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
1161       assert(0 && "Unexpected abbrev ordering!");
1162   }
1163   { // INST_BINOP abbrev for FUNCTION_BLOCK.
1164     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1165     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
1166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
1167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
1168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
1169     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1170                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
1171       assert(0 && "Unexpected abbrev ordering!");
1172   }
1173   { // INST_CAST abbrev for FUNCTION_BLOCK.
1174     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1175     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
1176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
1177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
1178                               Log2_32_Ceil(VE.getTypes().size()+1)));
1179     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
1180     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1181                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
1182       assert(0 && "Unexpected abbrev ordering!");
1183   }
1184
1185   { // INST_RET abbrev for FUNCTION_BLOCK.
1186     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1187     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1188     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1189                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
1190       assert(0 && "Unexpected abbrev ordering!");
1191   }
1192   { // INST_RET abbrev for FUNCTION_BLOCK.
1193     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1194     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
1195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
1196     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1197                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
1198       assert(0 && "Unexpected abbrev ordering!");
1199   }
1200   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
1201     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1202     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
1203     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
1204                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
1205       assert(0 && "Unexpected abbrev ordering!");
1206   }
1207
1208   Stream.ExitBlock();
1209 }
1210
1211
1212 /// WriteModule - Emit the specified module to the bitstream.
1213 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
1214   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
1215
1216   // Emit the version number if it is non-zero.
1217   if (CurVersion) {
1218     SmallVector<unsigned, 1> Vals;
1219     Vals.push_back(CurVersion);
1220     Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
1221   }
1222
1223   // Analyze the module, enumerating globals, functions, etc.
1224   ValueEnumerator VE(M);
1225
1226   // Emit blockinfo, which defines the standard abbreviations etc.
1227   WriteBlockInfo(VE, Stream);
1228
1229   // Emit information about parameter attributes.
1230   WriteAttributeTable(VE, Stream);
1231
1232   // Emit information describing all of the types in the module.
1233   WriteTypeTable(VE, Stream);
1234
1235   // Emit top-level description of module, including target triple, inline asm,
1236   // descriptors for global variables, and function prototype info.
1237   WriteModuleInfo(M, VE, Stream);
1238
1239   // Emit constants.
1240   WriteModuleConstants(VE, Stream);
1241
1242   // If we have any aggregate values in the value table, purge them - these can
1243   // only be used to initialize global variables.  Doing so makes the value
1244   // namespace smaller for code in functions.
1245   int NumNonAggregates = VE.PurgeAggregateValues();
1246   if (NumNonAggregates != -1) {
1247     SmallVector<unsigned, 1> Vals;
1248     Vals.push_back(NumNonAggregates);
1249     Stream.EmitRecord(bitc::MODULE_CODE_PURGEVALS, Vals);
1250   }
1251
1252   // Emit function bodies.
1253   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
1254     if (!I->isDeclaration())
1255       WriteFunction(*I, VE, Stream);
1256
1257   // Emit the type symbol table information.
1258   WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
1259
1260   // Emit names for globals/functions etc.
1261   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
1262
1263   Stream.ExitBlock();
1264 }
1265
1266 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
1267 /// header and trailer to make it compatible with the system archiver.  To do
1268 /// this we emit the following header, and then emit a trailer that pads the
1269 /// file out to be a multiple of 16 bytes.
1270 ///
1271 /// struct bc_header {
1272 ///   uint32_t Magic;         // 0x0B17C0DE
1273 ///   uint32_t Version;       // Version, currently always 0.
1274 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
1275 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
1276 ///   uint32_t CPUType;       // CPU specifier.
1277 ///   ... potentially more later ...
1278 /// };
1279 enum {
1280   DarwinBCSizeFieldOffset = 3*4, // Offset to bitcode_size.
1281   DarwinBCHeaderSize = 5*4
1282 };
1283
1284 static void EmitDarwinBCHeader(BitstreamWriter &Stream,
1285                                const std::string &TT) {
1286   unsigned CPUType = ~0U;
1287
1288   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*.  The CPUType is a
1289   // magic number from /usr/include/mach/machine.h.  It is ok to reproduce the
1290   // specific constants here because they are implicitly part of the Darwin ABI.
1291   enum {
1292     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
1293     DARWIN_CPU_TYPE_X86        = 7,
1294     DARWIN_CPU_TYPE_POWERPC    = 18
1295   };
1296
1297   if (TT.find("x86_64-") == 0)
1298     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
1299   else if (TT.size() >= 5 && TT[0] == 'i' && TT[2] == '8' && TT[3] == '6' &&
1300            TT[4] == '-' && TT[1] - '3' < 6)
1301     CPUType = DARWIN_CPU_TYPE_X86;
1302   else if (TT.find("powerpc-") == 0)
1303     CPUType = DARWIN_CPU_TYPE_POWERPC;
1304   else if (TT.find("powerpc64-") == 0)
1305     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
1306
1307   // Traditional Bitcode starts after header.
1308   unsigned BCOffset = DarwinBCHeaderSize;
1309
1310   Stream.Emit(0x0B17C0DE, 32);
1311   Stream.Emit(0         , 32);  // Version.
1312   Stream.Emit(BCOffset  , 32);
1313   Stream.Emit(0         , 32);  // Filled in later.
1314   Stream.Emit(CPUType   , 32);
1315 }
1316
1317 /// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
1318 /// finalize the header.
1319 static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
1320   // Update the size field in the header.
1321   Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
1322
1323   // If the file is not a multiple of 16 bytes, insert dummy padding.
1324   while (BufferSize & 15) {
1325     Stream.Emit(0, 8);
1326     ++BufferSize;
1327   }
1328 }
1329
1330
1331 /// WriteBitcodeToFile - Write the specified module to the specified output
1332 /// stream.
1333 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
1334   raw_os_ostream RawOut(Out);
1335   // If writing to stdout, set binary mode.
1336   if (llvm::cout == Out)
1337     sys::Program::ChangeStdoutToBinary();
1338   WriteBitcodeToFile(M, RawOut);
1339 }
1340
1341 /// WriteBitcodeToFile - Write the specified module to the specified output
1342 /// stream.
1343 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
1344   std::vector<unsigned char> Buffer;
1345   BitstreamWriter Stream(Buffer);
1346
1347   Buffer.reserve(256*1024);
1348
1349   // If this is darwin, emit a file header and trailer if needed.
1350   bool isDarwin = M->getTargetTriple().find("-darwin") != std::string::npos;
1351   if (isDarwin)
1352     EmitDarwinBCHeader(Stream, M->getTargetTriple());
1353
1354   // Emit the file header.
1355   Stream.Emit((unsigned)'B', 8);
1356   Stream.Emit((unsigned)'C', 8);
1357   Stream.Emit(0x0, 4);
1358   Stream.Emit(0xC, 4);
1359   Stream.Emit(0xE, 4);
1360   Stream.Emit(0xD, 4);
1361
1362   // Emit the module.
1363   WriteModule(M, Stream);
1364
1365   if (isDarwin)
1366     EmitDarwinBCTrailer(Stream, Buffer.size());
1367
1368
1369   // If writing to stdout, set binary mode.
1370   if (&llvm::outs() == &Out)
1371     sys::Program::ChangeStdoutToBinary();
1372
1373   // Write the generated bitstream to "Out".
1374   Out.write((char*)&Buffer.front(), Buffer.size());
1375
1376   // Make sure it hits disk now.
1377   Out.flush();
1378 }