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