tools/lto/LTOModule.cpp

   1 //===-- LTOModule.cpp - LLVM Link Time Optimizer --------------------------===//
   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 // This file implements the Link Time Optimization library. This library is
  11 // intended to be used by linker to optimize code at link time.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "LTOModule.h"
  16
  17 #include "llvm/Constants.h"
  18 #include "llvm/LLVMContext.h"
  19 #include "llvm/Module.h"
  20 #include "llvm/ADT/OwningPtr.h"
  21 #include "llvm/ADT/Triple.h"
  22 #include "llvm/Bitcode/ReaderWriter.h"
  23 #include "llvm/Support/SystemUtils.h"
  24 #include "llvm/Support/MemoryBuffer.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/Host.h"
  27 #include "llvm/Support/Path.h"
  28 #include "llvm/Support/Process.h"
  29 #include "llvm/Support/SourceMgr.h"
  30 #include "llvm/Support/system_error.h"
  31 #include "llvm/Target/Mangler.h"
  32 #include "llvm/MC/MCAsmInfo.h"
  33 #include "llvm/MC/MCContext.h"
  34 #include "llvm/MC/MCExpr.h"
  35 #include "llvm/MC/MCInst.h"
  36 #include "llvm/MC/MCParser/MCAsmParser.h"
  37 #include "llvm/MC/MCStreamer.h"
  38 #include "llvm/MC/MCSubtargetInfo.h"
  39 #include "llvm/MC/MCSymbol.h"
  40 #include "llvm/MC/SubtargetFeature.h"
  41 #include "llvm/Target/TargetAsmParser.h"
  42 #include "llvm/Target/TargetMachine.h"
  43 #include "llvm/Target/TargetRegistry.h"
  44 #include "llvm/Target/TargetSelect.h"
  45
  46 using namespace llvm;
  47
  48 bool LTOModule::isBitcodeFile(const void *mem, size_t length) {
  49   return llvm::sys::IdentifyFileType((char*)mem, length)
  50     == llvm::sys::Bitcode_FileType;
  51 }
  52
  53 bool LTOModule::isBitcodeFile(const char *path) {
  54   return llvm::sys::Path(path).isBitcodeFile();
  55 }
  56
  57 bool LTOModule::isBitcodeFileForTarget(const void *mem, size_t length,
  58                                        const char *triplePrefix) {
  59   MemoryBuffer *buffer = makeBuffer(mem, length);
  60   if (!buffer)
  61     return false;
  62   return isTargetMatch(buffer, triplePrefix);
  63 }
  64
  65
  66 bool LTOModule::isBitcodeFileForTarget(const char *path,
  67                                        const char *triplePrefix) {
  68   OwningPtr<MemoryBuffer> buffer;
  69   if (MemoryBuffer::getFile(path, buffer))
  70     return false;
  71   return isTargetMatch(buffer.take(), triplePrefix);
  72 }
  73
  74 // Takes ownership of buffer.
  75 bool LTOModule::isTargetMatch(MemoryBuffer *buffer, const char *triplePrefix) {
  76   std::string Triple = getBitcodeTargetTriple(buffer, getGlobalContext());
  77   delete buffer;
  78   return (strncmp(Triple.c_str(), triplePrefix,
  79                   strlen(triplePrefix)) == 0);
  80 }
  81
  82
  83 LTOModule::LTOModule(Module *m, TargetMachine *t)
  84   : _module(m), _target(t)
  85 {
  86 }
  87
  88 LTOModule *LTOModule::makeLTOModule(const char *path,
  89                                     std::string &errMsg) {
  90   OwningPtr<MemoryBuffer> buffer;
  91   if (error_code ec = MemoryBuffer::getFile(path, buffer)) {
  92     errMsg = ec.message();
  93     return NULL;
  94   }
  95   return makeLTOModule(buffer.take(), errMsg);
  96 }
  97
  98 LTOModule *LTOModule::makeLTOModule(int fd, const char *path,
  99                                     size_t size,
 100                                     std::string &errMsg) {
 101   return makeLTOModule(fd, path, size, size, 0, errMsg);
 102 }
 103
 104 LTOModule *LTOModule::makeLTOModule(int fd, const char *path,
 105                                     size_t file_size,
 106                                     size_t map_size,
 107                                     off_t offset,
 108                                     std::string &errMsg) {
 109   OwningPtr<MemoryBuffer> buffer;
 110   if (error_code ec = MemoryBuffer::getOpenFile(fd, path, buffer, file_size,
 111                                                 map_size, offset, false)) {
 112     errMsg = ec.message();
 113     return NULL;
 114   }
 115   return makeLTOModule(buffer.take(), errMsg);
 116 }
 117
 118 /// makeBuffer - Create a MemoryBuffer from a memory range.
 119 MemoryBuffer *LTOModule::makeBuffer(const void *mem, size_t length) {
 120   const char *startPtr = (char*)mem;
 121   return MemoryBuffer::getMemBuffer(StringRef(startPtr, length), "", false);
 122 }
 123
 124
 125 LTOModule *LTOModule::makeLTOModule(const void *mem, size_t length,
 126                                     std::string &errMsg) {
 127   OwningPtr<MemoryBuffer> buffer(makeBuffer(mem, length));
 128   if (!buffer)
 129     return NULL;
 130   return makeLTOModule(buffer.take(), errMsg);
 131 }
 132
 133 LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
 134                                     std::string &errMsg) {
 135   static bool Initialized = false;
 136   if (!Initialized) {
 137     InitializeAllTargets();
 138     InitializeAllAsmParsers();
 139     Initialized = true;
 140   }
 141
 142   // parse bitcode buffer
 143   OwningPtr<Module> m(getLazyBitcodeModule(buffer, getGlobalContext(),
 144                                            &errMsg));
 145   if (!m) {
 146     delete buffer;
 147     return NULL;
 148   }
 149
 150   std::string Triple = m->getTargetTriple();
 151   if (Triple.empty())
 152     Triple = sys::getHostTriple();
 153
 154   // find machine architecture for this module
 155   const Target *march = TargetRegistry::lookupTarget(Triple, errMsg);
 156   if (!march)
 157     return NULL;
 158
 159   // construct LTOModule, hand over ownership of module and target
 160   SubtargetFeatures Features;
 161   Features.getDefaultSubtargetFeatures(llvm::Triple(Triple));
 162   std::string FeatureStr = Features.getString();
 163   std::string CPU;
 164   TargetMachine *target = march->createTargetMachine(Triple, CPU, FeatureStr);
 165   LTOModule *Ret = new LTOModule(m.take(), target);
 166   bool Err = Ret->ParseSymbols();
 167   if (Err) {
 168     delete Ret;
 169     return NULL;
 170   }
 171   return Ret;
 172 }
 173
 174
 175 const char *LTOModule::getTargetTriple() {
 176   return _module->getTargetTriple().c_str();
 177 }
 178
 179 void LTOModule::setTargetTriple(const char *triple) {
 180   _module->setTargetTriple(triple);
 181 }
 182
 183 void LTOModule::addDefinedFunctionSymbol(Function *f, Mangler &mangler) {
 184   // add to list of defined symbols
 185   addDefinedSymbol(f, mangler, true);
 186 }
 187
 188 // Get string that data pointer points to.
 189 bool LTOModule::objcClassNameFromExpression(Constant *c, std::string &name) {
 190   if (ConstantExpr *ce = dyn_cast<ConstantExpr>(c)) {
 191     Constant *op = ce->getOperand(0);
 192     if (GlobalVariable *gvn = dyn_cast<GlobalVariable>(op)) {
 193       Constant *cn = gvn->getInitializer();
 194       if (ConstantArray *ca = dyn_cast<ConstantArray>(cn)) {
 195         if (ca->isCString()) {
 196           name = ".objc_class_name_" + ca->getAsCString();
 197           return true;
 198         }
 199       }
 200     }
 201   }
 202   return false;
 203 }
 204
 205 // Parse i386/ppc ObjC class data structure.
 206 void LTOModule::addObjCClass(GlobalVariable *clgv) {
 207   if (ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer())) {
 208     // second slot in __OBJC,__class is pointer to superclass name
 209     std::string superclassName;
 210     if (objcClassNameFromExpression(c->getOperand(1), superclassName)) {
 211       NameAndAttributes info;
 212       StringMap<NameAndAttributes>::value_type &entry =
 213         _undefines.GetOrCreateValue(superclassName);
 214       if (!entry.getValue().name) {
 215         const char *symbolName = entry.getKey().data();
 216         info.name = symbolName;
 217         info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
 218         entry.setValue(info);
 219       }
 220     }
 221     // third slot in __OBJC,__class is pointer to class name
 222     std::string className;
 223     if (objcClassNameFromExpression(c->getOperand(2), className)) {
 224       StringSet::value_type &entry =
 225         _defines.GetOrCreateValue(className);
 226       entry.setValue(1);
 227       NameAndAttributes info;
 228       info.name = entry.getKey().data();
 229       info.attributes = (lto_symbol_attributes)
 230         (LTO_SYMBOL_PERMISSIONS_DATA |
 231          LTO_SYMBOL_DEFINITION_REGULAR |
 232          LTO_SYMBOL_SCOPE_DEFAULT);
 233       _symbols.push_back(info);
 234     }
 235   }
 236 }
 237
 238
 239 // Parse i386/ppc ObjC category data structure.
 240 void LTOModule::addObjCCategory(GlobalVariable *clgv) {
 241   if (ConstantStruct *c = dyn_cast<ConstantStruct>(clgv->getInitializer())) {
 242     // second slot in __OBJC,__category is pointer to target class name
 243     std::string targetclassName;
 244     if (objcClassNameFromExpression(c->getOperand(1), targetclassName)) {
 245       NameAndAttributes info;
 246
 247       StringMap<NameAndAttributes>::value_type &entry =
 248         _undefines.GetOrCreateValue(targetclassName);
 249
 250       if (entry.getValue().name)
 251         return;
 252
 253       const char *symbolName = entry.getKey().data();
 254       info.name = symbolName;
 255       info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
 256       entry.setValue(info);
 257     }
 258   }
 259 }
 260
 261
 262 // Parse i386/ppc ObjC class list data structure.
 263 void LTOModule::addObjCClassRef(GlobalVariable *clgv) {
 264   std::string targetclassName;
 265   if (objcClassNameFromExpression(clgv->getInitializer(), targetclassName)) {
 266     NameAndAttributes info;
 267
 268     StringMap<NameAndAttributes>::value_type &entry =
 269       _undefines.GetOrCreateValue(targetclassName);
 270     if (entry.getValue().name)
 271       return;
 272
 273     const char *symbolName = entry.getKey().data();
 274     info.name = symbolName;
 275     info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
 276     entry.setValue(info);
 277   }
 278 }
 279
 280
 281 void LTOModule::addDefinedDataSymbol(GlobalValue *v, Mangler &mangler) {
 282   // Add to list of defined symbols.
 283   addDefinedSymbol(v, mangler, false);
 284
 285   // Special case i386/ppc ObjC data structures in magic sections:
 286   // The issue is that the old ObjC object format did some strange
 287   // contortions to avoid real linker symbols.  For instance, the
 288   // ObjC class data structure is allocated statically in the executable
 289   // that defines that class.  That data structures contains a pointer to
 290   // its superclass.  But instead of just initializing that part of the
 291   // struct to the address of its superclass, and letting the static and
 292   // dynamic linkers do the rest, the runtime works by having that field
 293   // instead point to a C-string that is the name of the superclass.
 294   // At runtime the objc initialization updates that pointer and sets
 295   // it to point to the actual super class.  As far as the linker
 296   // knows it is just a pointer to a string.  But then someone wanted the
 297   // linker to issue errors at build time if the superclass was not found.
 298   // So they figured out a way in mach-o object format to use an absolute
 299   // symbols (.objc_class_name_Foo = 0) and a floating reference
 300   // (.reference .objc_class_name_Bar) to cause the linker into erroring when
 301   // a class was missing.
 302   // The following synthesizes the implicit .objc_* symbols for the linker
 303   // from the ObjC data structures generated by the front end.
 304   if (v->hasSection() /* && isTargetDarwin */) {
 305     // special case if this data blob is an ObjC class definition
 306     if (v->getSection().compare(0, 15, "__OBJC,__class,") == 0) {
 307       if (GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) {
 308         addObjCClass(gv);
 309       }
 310     }
 311
 312     // special case if this data blob is an ObjC category definition
 313     else if (v->getSection().compare(0, 18, "__OBJC,__category,") == 0) {
 314       if (GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) {
 315         addObjCCategory(gv);
 316       }
 317     }
 318
 319     // special case if this data blob is the list of referenced classes
 320     else if (v->getSection().compare(0, 18, "__OBJC,__cls_refs,") == 0) {
 321       if (GlobalVariable *gv = dyn_cast<GlobalVariable>(v)) {
 322         addObjCClassRef(gv);
 323       }
 324     }
 325   }
 326 }
 327
 328
 329 void LTOModule::addDefinedSymbol(GlobalValue *def, Mangler &mangler,
 330                                  bool isFunction) {
 331   // ignore all llvm.* symbols
 332   if (def->getName().startswith("llvm."))
 333     return;
 334
 335   // string is owned by _defines
 336   SmallString<64> Buffer;
 337   mangler.getNameWithPrefix(Buffer, def, false);
 338
 339   // set alignment part log2() can have rounding errors
 340   uint32_t align = def->getAlignment();
 341   uint32_t attr = align ? CountTrailingZeros_32(def->getAlignment()) : 0;
 342
 343   // set permissions part
 344   if (isFunction)
 345     attr |= LTO_SYMBOL_PERMISSIONS_CODE;
 346   else {
 347     GlobalVariable *gv = dyn_cast<GlobalVariable>(def);
 348     if (gv && gv->isConstant())
 349       attr |= LTO_SYMBOL_PERMISSIONS_RODATA;
 350     else
 351       attr |= LTO_SYMBOL_PERMISSIONS_DATA;
 352   }
 353
 354   // set definition part
 355   if (def->hasWeakLinkage() || def->hasLinkOnceLinkage() ||
 356       def->hasLinkerPrivateWeakLinkage() ||
 357       def->hasLinkerPrivateWeakDefAutoLinkage())
 358     attr |= LTO_SYMBOL_DEFINITION_WEAK;
 359   else if (def->hasCommonLinkage())
 360     attr |= LTO_SYMBOL_DEFINITION_TENTATIVE;
 361   else
 362     attr |= LTO_SYMBOL_DEFINITION_REGULAR;
 363
 364   // set scope part
 365   if (def->hasHiddenVisibility())
 366     attr |= LTO_SYMBOL_SCOPE_HIDDEN;
 367   else if (def->hasProtectedVisibility())
 368     attr |= LTO_SYMBOL_SCOPE_PROTECTED;
 369   else if (def->hasExternalLinkage() || def->hasWeakLinkage() ||
 370            def->hasLinkOnceLinkage() || def->hasCommonLinkage() ||
 371            def->hasLinkerPrivateWeakLinkage())
 372     attr |= LTO_SYMBOL_SCOPE_DEFAULT;
 373   else if (def->hasLinkerPrivateWeakDefAutoLinkage())
 374     attr |= LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN;
 375   else
 376     attr |= LTO_SYMBOL_SCOPE_INTERNAL;
 377
 378   // add to table of symbols
 379   NameAndAttributes info;
 380   StringSet::value_type &entry = _defines.GetOrCreateValue(Buffer);
 381   entry.setValue(1);
 382
 383   StringRef Name = entry.getKey();
 384   info.name = Name.data();
 385   assert(info.name[Name.size()] == '\0');
 386   info.attributes = (lto_symbol_attributes)attr;
 387   _symbols.push_back(info);
 388 }
 389
 390 void LTOModule::addAsmGlobalSymbol(const char *name,
 391                                    lto_symbol_attributes scope) {
 392   StringSet::value_type &entry = _defines.GetOrCreateValue(name);
 393
 394   // only add new define if not already defined
 395   if (entry.getValue())
 396     return;
 397
 398   entry.setValue(1);
 399   const char *symbolName = entry.getKey().data();
 400   uint32_t attr = LTO_SYMBOL_DEFINITION_REGULAR;
 401   attr |= scope;
 402   NameAndAttributes info;
 403   info.name = symbolName;
 404   info.attributes = (lto_symbol_attributes)attr;
 405   _symbols.push_back(info);
 406 }
 407
 408 void LTOModule::addAsmGlobalSymbolUndef(const char *name) {
 409   StringMap<NameAndAttributes>::value_type &entry =
 410     _undefines.GetOrCreateValue(name);
 411
 412   _asm_undefines.push_back(entry.getKey().data());
 413
 414   // we already have the symbol
 415   if (entry.getValue().name)
 416     return;
 417
 418   uint32_t attr = LTO_SYMBOL_DEFINITION_UNDEFINED;;
 419   attr |= LTO_SYMBOL_SCOPE_DEFAULT;
 420   NameAndAttributes info;
 421   info.name = entry.getKey().data();
 422   info.attributes = (lto_symbol_attributes)attr;
 423
 424   entry.setValue(info);
 425 }
 426
 427 void LTOModule::addPotentialUndefinedSymbol(GlobalValue *decl,
 428                                             Mangler &mangler) {
 429   // ignore all llvm.* symbols
 430   if (decl->getName().startswith("llvm."))
 431     return;
 432
 433   // ignore all aliases
 434   if (isa<GlobalAlias>(decl))
 435     return;
 436
 437   SmallString<64> name;
 438   mangler.getNameWithPrefix(name, decl, false);
 439
 440   StringMap<NameAndAttributes>::value_type &entry =
 441     _undefines.GetOrCreateValue(name);
 442
 443   // we already have the symbol
 444   if (entry.getValue().name)
 445     return;
 446
 447   NameAndAttributes info;
 448
 449   info.name = entry.getKey().data();
 450   if (decl->hasExternalWeakLinkage())
 451     info.attributes = LTO_SYMBOL_DEFINITION_WEAKUNDEF;
 452   else
 453     info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
 454
 455   entry.setValue(info);
 456 }
 457
 458
 459 namespace {
 460   class RecordStreamer : public MCStreamer {
 461   public:
 462     enum State { NeverSeen, Global, Defined, DefinedGlobal, Used};
 463
 464   private:
 465     StringMap<State> Symbols;
 466
 467     void markDefined(const MCSymbol &Symbol) {
 468       State &S = Symbols[Symbol.getName()];
 469       switch (S) {
 470       case DefinedGlobal:
 471       case Global:
 472         S = DefinedGlobal;
 473         break;
 474       case NeverSeen:
 475       case Defined:
 476       case Used:
 477         S = Defined;
 478         break;
 479       }
 480     }
 481     void markGlobal(const MCSymbol &Symbol) {
 482       State &S = Symbols[Symbol.getName()];
 483       switch (S) {
 484       case DefinedGlobal:
 485       case Defined:
 486         S = DefinedGlobal;
 487         break;
 488
 489       case NeverSeen:
 490       case Global:
 491       case Used:
 492         S = Global;
 493         break;
 494       }
 495     }
 496     void markUsed(const MCSymbol &Symbol) {
 497       State &S = Symbols[Symbol.getName()];
 498       switch (S) {
 499       case DefinedGlobal:
 500       case Defined:
 501       case Global:
 502         break;
 503
 504       case NeverSeen:
 505       case Used:
 506         S = Used;
 507         break;
 508       }
 509     }
 510
 511     // FIXME: mostly copied for the obj streamer.
 512     void AddValueSymbols(const MCExpr *Value) {
 513       switch (Value->getKind()) {
 514       case MCExpr::Target:
 515         // FIXME: What should we do in here?
 516         break;
 517
 518       case MCExpr::Constant:
 519         break;
 520
 521       case MCExpr::Binary: {
 522         const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
 523         AddValueSymbols(BE->getLHS());
 524         AddValueSymbols(BE->getRHS());
 525         break;
 526       }
 527
 528       case MCExpr::SymbolRef:
 529         markUsed(cast<MCSymbolRefExpr>(Value)->getSymbol());
 530         break;
 531
 532       case MCExpr::Unary:
 533         AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
 534         break;
 535       }
 536     }
 537
 538   public:
 539     typedef StringMap<State>::const_iterator const_iterator;
 540
 541     const_iterator begin() {
 542       return Symbols.begin();
 543     }
 544
 545     const_iterator end() {
 546       return Symbols.end();
 547     }
 548
 549     RecordStreamer(MCContext &Context) : MCStreamer(Context) {}
 550
 551     virtual void ChangeSection(const MCSection *Section) {}
 552     virtual void InitSections() {}
 553     virtual void EmitLabel(MCSymbol *Symbol) {
 554       Symbol->setSection(*getCurrentSection());
 555       markDefined(*Symbol);
 556     }
 557     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {}
 558     virtual void EmitThumbFunc(MCSymbol *Func) {}
 559     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
 560       // FIXME: should we handle aliases?
 561       markDefined(*Symbol);
 562     }
 563     virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
 564       if (Attribute == MCSA_Global)
 565         markGlobal(*Symbol);
 566     }
 567     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
 568     virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
 569     virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
 570     virtual void EmitCOFFSymbolStorageClass(int StorageClass) {}
 571     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
 572                               unsigned Size , unsigned ByteAlignment) {
 573       markDefined(*Symbol);
 574     }
 575     virtual void EmitCOFFSymbolType(int Type) {}
 576     virtual void EndCOFFSymbolDef() {}
 577     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
 578                                   unsigned ByteAlignment) {
 579       markDefined(*Symbol);
 580     }
 581     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
 582     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {}
 583     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
 584                                 uint64_t Size, unsigned ByteAlignment) {}
 585     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) {}
 586     virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
 587                                unsigned AddrSpace) {}
 588     virtual void EmitULEB128Value(const MCExpr *Value) {}
 589     virtual void EmitSLEB128Value(const MCExpr *Value) {}
 590     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
 591                                       unsigned ValueSize,
 592                                       unsigned MaxBytesToEmit) {}
 593     virtual void EmitCodeAlignment(unsigned ByteAlignment,
 594                                    unsigned MaxBytesToEmit) {}
 595     virtual void EmitValueToOffset(const MCExpr *Offset,
 596                                    unsigned char Value ) {}
 597     virtual void EmitFileDirective(StringRef Filename) {}
 598     virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
 599                                           const MCSymbol *LastLabel,
 600                                         const MCSymbol *Label) {}
 601
 602     virtual void EmitInstruction(const MCInst &Inst) {
 603       // Scan for values.
 604       for (unsigned i = Inst.getNumOperands(); i--; )
 605         if (Inst.getOperand(i).isExpr())
 606           AddValueSymbols(Inst.getOperand(i).getExpr());
 607     }
 608     virtual void Finish() {}
 609   };
 610 }
 611
 612 bool LTOModule::addAsmGlobalSymbols(MCContext &Context) {
 613   const std::string &inlineAsm = _module->getModuleInlineAsm();
 614
 615   OwningPtr<RecordStreamer> Streamer(new RecordStreamer(Context));
 616   MemoryBuffer *Buffer = MemoryBuffer::getMemBuffer(inlineAsm);
 617   SourceMgr SrcMgr;
 618   SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
 619   OwningPtr<MCAsmParser> Parser(createMCAsmParser(_target->getTarget(), SrcMgr,
 620                                                   Context, *Streamer,
 621                                                   *_target->getMCAsmInfo()));
 622   OwningPtr<MCSubtargetInfo> STI(_target->getTarget().
 623                       createMCSubtargetInfo(_target->getTargetTriple(),
 624                                             _target->getTargetCPU(),
 625                                             _target->getTargetFeatureString()));
 626   OwningPtr<TargetAsmParser>
 627     TAP(_target->getTarget().createAsmParser(*STI, *Parser.get()));
 628   Parser->setTargetParser(*TAP);
 629   int Res = Parser->Run(false);
 630   if (Res)
 631     return true;
 632
 633   for (RecordStreamer::const_iterator i = Streamer->begin(),
 634          e = Streamer->end(); i != e; ++i) {
 635     StringRef Key = i->first();
 636     RecordStreamer::State Value = i->second;
 637     if (Value == RecordStreamer::DefinedGlobal)
 638       addAsmGlobalSymbol(Key.data(), LTO_SYMBOL_SCOPE_DEFAULT);
 639     else if (Value == RecordStreamer::Defined)
 640       addAsmGlobalSymbol(Key.data(), LTO_SYMBOL_SCOPE_INTERNAL);
 641     else if (Value == RecordStreamer::Global ||
 642              Value == RecordStreamer::Used)
 643       addAsmGlobalSymbolUndef(Key.data());
 644   }
 645   return false;
 646 }
 647
 648 static bool isDeclaration(const GlobalValue &V) {
 649   if (V.hasAvailableExternallyLinkage())
 650     return true;
 651   if (V.isMaterializable())
 652     return false;
 653   return V.isDeclaration();
 654 }
 655
 656 static bool isAliasToDeclaration(const GlobalAlias &V) {
 657   return isDeclaration(*V.getAliasedGlobal());
 658 }
 659
 660 bool LTOModule::ParseSymbols() {
 661   // Use mangler to add GlobalPrefix to names to match linker names.
 662   MCContext Context(*_target->getMCAsmInfo(), NULL);
 663   Mangler mangler(Context, *_target->getTargetData());
 664
 665   // add functions
 666   for (Module::iterator f = _module->begin(); f != _module->end(); ++f) {
 667     if (isDeclaration(*f))
 668       addPotentialUndefinedSymbol(f, mangler);
 669     else
 670       addDefinedFunctionSymbol(f, mangler);
 671   }
 672
 673   // add data
 674   for (Module::global_iterator v = _module->global_begin(),
 675          e = _module->global_end(); v !=  e; ++v) {
 676     if (isDeclaration(*v))
 677       addPotentialUndefinedSymbol(v, mangler);
 678     else
 679       addDefinedDataSymbol(v, mangler);
 680   }
 681
 682   // add asm globals
 683   if (addAsmGlobalSymbols(Context))
 684     return true;
 685
 686   // add aliases
 687   for (Module::alias_iterator i = _module->alias_begin(),
 688          e = _module->alias_end(); i != e; ++i) {
 689     if (isAliasToDeclaration(*i))
 690       addPotentialUndefinedSymbol(i, mangler);
 691     else
 692       addDefinedDataSymbol(i, mangler);
 693   }
 694
 695   // make symbols for all undefines
 696   for (StringMap<NameAndAttributes>::iterator it=_undefines.begin();
 697        it != _undefines.end(); ++it) {
 698     // if this symbol also has a definition, then don't make an undefine
 699     // because it is a tentative definition
 700     if (_defines.count(it->getKey()) == 0) {
 701       NameAndAttributes info = it->getValue();
 702       _symbols.push_back(info);
 703     }
 704   }
 705   return false;
 706 }
 707
 708
 709 uint32_t LTOModule::getSymbolCount() {
 710   return _symbols.size();
 711 }
 712
 713
 714 lto_symbol_attributes LTOModule::getSymbolAttributes(uint32_t index) {
 715   if (index < _symbols.size())
 716     return _symbols[index].attributes;
 717   else
 718     return lto_symbol_attributes(0);
 719 }
 720
 721 const char *LTOModule::getSymbolName(uint32_t index) {
 722   if (index < _symbols.size())
 723     return _symbols[index].name;
 724   else
 725     return NULL;
 726 }