C++ module::global_iterator类代码示例

void LTOCodeGenerator::applyScopeRestrictions() {
  if (_scopeRestrictionsDone) return;
  Module *mergedModule = _linker.getModule();

  // Start off with a verification pass.
  PassManager passes;
  passes.add(createVerifierPass());

  // mark which symbols can not be internalized 
  if (!_mustPreserveSymbols.empty()) {
    MCContext Context(*_target->getMCAsmInfo(), NULL);
    Mangler mangler(Context, *_target->getTargetData());
    std::vector<const char*> mustPreserveList;
    for (Module::iterator f = mergedModule->begin(),
         e = mergedModule->end(); f != e; ++f) {
      if (!f->isDeclaration() &&
          _mustPreserveSymbols.count(mangler.getNameWithPrefix(f)))
        mustPreserveList.push_back(::strdup(f->getNameStr().c_str()));
    }
    for (Module::global_iterator v = mergedModule->global_begin(), 
         e = mergedModule->global_end(); v !=  e; ++v) {
      if (!v->isDeclaration() &&
          _mustPreserveSymbols.count(mangler.getNameWithPrefix(v)))
        mustPreserveList.push_back(::strdup(v->getNameStr().c_str()));
    }
    passes.add(createInternalizePass(mustPreserveList));
  }
  
  // apply scope restrictions
  passes.run(*mergedModule);
  
  _scopeRestrictionsDone = true;
}

/// doInitialization - Perfrom Module level initializations here.
/// One task that we do here is to sectionize all global variables.
/// The MemSelOptimizer pass depends on the sectionizing.
///
bool PIC16AsmPrinter::doInitialization(Module &M) {
  bool Result = AsmPrinter::doInitialization(M);

  // FIXME:: This is temporary solution to generate the include file.
  // The processor should be passed to llc as in input and the header file
  // should be generated accordingly.
  O << "\n\t#include P16F1937.INC\n";

  // Set the section names for all globals.
  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage()) {
      const MCSection *S = getObjFileLowering().SectionForGlobal(I, Mang, TM);
      
      I->setSection(((const MCSectionPIC16*)S)->getName());
    }

  DbgInfo.BeginModule(M);
  EmitFunctionDecls(M);
  EmitUndefinedVars(M);
  EmitDefinedVars(M);
  EmitIData(M);
  EmitUData(M);
  EmitRomData(M);
  return Result;
}

/// StripSymbolNames - Strip symbol names.
static bool StripSymbolNames(Module &M, bool PreserveDbgInfo) {

  SmallPtrSet<const GlobalValue*, 8> llvmUsedValues;
  findUsedValues(M.getGlobalVariable("llvm.used"), llvmUsedValues);
  findUsedValues(M.getGlobalVariable("llvm.compiler.used"), llvmUsedValues);

  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
        I->setName("");     // Internal symbols can't participate in linkage
  }
  
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
        I->setName("");     // Internal symbols can't participate in linkage
    StripSymtab(I->getValueSymbolTable(), PreserveDbgInfo);
  }
  
  // Remove all names from types.
  StripTypeSymtab(M.getTypeSymbolTable(), PreserveDbgInfo);

  return true;
}

void PIC16AsmPrinter::EmitRomData (Module &M)
{
  SwitchToSection(TAI->getReadOnlySection());
  IsRomData = true;
  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    if (!I->hasInitializer())   // External global require no code.
      continue;

    Constant *C = I->getInitializer();
    const PointerType *PtrTy = I->getType();
    int AddrSpace = PtrTy->getAddressSpace();
    if ((!C->isNullValue()) && (AddrSpace == PIC16ISD::ROM_SPACE)) {

      if (EmitSpecialLLVMGlobal(I))
        continue;

      // Any variables reaching here with "." in its name is a local scope
      // variable and should not be printed in global data section.
      std::string name = Mang->getValueName(I);
      if (name.find(".") != std::string::npos)
        continue;

      I->setSection(TAI->getReadOnlySection()->getName());
      O << name;
      EmitGlobalConstant(C, AddrSpace);
      O << "\n";
    }
  }
  IsRomData = false;
}

/// AnalyzeGlobals - Scan through the users of all of the internal
/// GlobalValue's in the program.  If none of them have their "address taken"
/// (really, their address passed to something nontrivial), record this fact,
/// and record the functions that they are used directly in.
void GlobalsModRef::AnalyzeGlobals(Module &M) {
  std::vector<Function*> Readers, Writers;
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (I->hasLocalLinkage()) {
      if (!AnalyzeUsesOfPointer(I, Readers, Writers)) {
        // Remember that we are tracking this global.
        NonAddressTakenGlobals.insert(I);
        ++NumNonAddrTakenFunctions;
      }
      Readers.clear(); Writers.clear();
    }

  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    if (I->hasLocalLinkage()) {
      if (!AnalyzeUsesOfPointer(I, Readers, Writers)) {
        // Remember that we are tracking this global, and the mod/ref fns
        NonAddressTakenGlobals.insert(I);

        for (unsigned i = 0, e = Readers.size(); i != e; ++i)
          FunctionInfo[Readers[i]].GlobalInfo[I] |= Ref;

        if (!I->isConstant())  // No need to keep track of writers to constants
          for (unsigned i = 0, e = Writers.size(); i != e; ++i)
            FunctionInfo[Writers[i]].GlobalInfo[I] |= Mod;
        ++NumNonAddrTakenGlobalVars;

        // If this global holds a pointer type, see if it is an indirect global.
        if (I->getType()->getElementType()->isPointerTy() &&
            AnalyzeIndirectGlobalMemory(I))
          ++NumIndirectGlobalVars;
      }
      Readers.clear(); Writers.clear();
    }
}

/// computeTypeMapping - Loop over all of the linked values to compute type
/// mappings.  For example, if we link "extern Foo *x" and "Foo *x = NULL", then
/// we have two struct types 'Foo' but one got renamed when the module was
/// loaded into the same LLVMContext.
void ModuleLinker::computeTypeMapping() {
  // Incorporate globals.
  for (Module::global_iterator I = SrcM->global_begin(),
       E = SrcM->global_end(); I != E; ++I) {
    GlobalValue *DGV = getLinkedToGlobal(I);
    if (DGV == 0) continue;
    
    if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
      TypeMap.addTypeMapping(DGV->getType(), I->getType());
      continue;      
    }
    
    // Unify the element type of appending arrays.
    ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
    ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
    TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
  }
  
  // Incorporate functions.
  for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
    if (GlobalValue *DGV = getLinkedToGlobal(I))
      TypeMap.addTypeMapping(DGV->getType(), I->getType());
  }

  // Incorporate types by name, scanning all the types in the source module.
  // At this point, the destination module may have a type "%foo = { i32 }" for
  // example.  When the source module got loaded into the same LLVMContext, if
  // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
  // Though it isn't required for correctness, attempt to link these up to clean
  // up the IR.
  std::vector<StructType*> SrcStructTypes;
  SrcM->findUsedStructTypes(SrcStructTypes);
  
  SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
                                                 SrcStructTypes.end());
  
  for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
    StructType *ST = SrcStructTypes[i];
    if (!ST->hasName()) continue;
    
    // Check to see if there is a dot in the name followed by a digit.
    size_t DotPos = ST->getName().rfind('.');
    if (DotPos == 0 || DotPos == StringRef::npos ||
        ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1]))
      continue;
    
    // Check to see if the destination module has a struct with the prefix name.
    if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
      // Don't use it if this actually came from the source module.  They're in
      // the same LLVMContext after all.
      if (!SrcStructTypesSet.count(DST))
        TypeMap.addTypeMapping(DST, ST);
  }

  // Don't bother incorporating aliases, they aren't generally typed well.
  
  // Now that we have discovered all of the type equivalences, get a body for
  // any 'opaque' types in the dest module that are now resolved. 
  TypeMap.linkDefinedTypeBodies();
}

bool PIC16AsmPrinter::doInitialization (Module &M) {
  bool Result = AsmPrinter::doInitialization(M);
  DbgInfo.EmitFileDirective(M);

  // FIXME:: This is temporary solution to generate the include file.
  // The processor should be passed to llc as in input and the header file
  // should be generated accordingly.
  O << "\n\t#include P16F1937.INC\n";
  MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
  assert(MMI);
  DwarfWriter *DW = getAnalysisIfAvailable<DwarfWriter>();
  assert(DW && "Dwarf Writer is not available");
  DW->BeginModule(&M, MMI, O, this, TAI);

  // Set the section names for all globals.
  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    I->setSection(TAI->SectionForGlobal(I)->getName());
  }

  EmitFunctionDecls(M);
  EmitUndefinedVars(M);
  EmitDefinedVars(M);
  EmitIData(M);
  EmitUData(M);
  EmitRomData(M);
  DbgInfo.PopulateFunctsDI(M); 
  return Result;
}

void MemoryInstrumenter::instrumentGlobals(Module &M) {
  TargetData &TD = getAnalysis<TargetData>();
  IDAssigner &IDA = getAnalysis<IDAssigner>();

  // Function HookGlobalsAlloc contains only one basic block.
  // The BB iterates through all global variables, and calls HookMemAlloc
  // for each of them.
  BasicBlock *BB = BasicBlock::Create(M.getContext(), "entry",
                                      GlobalsAllocHook);
  Instruction *Ret = ReturnInst::Create(M.getContext(), BB);

  for (Module::global_iterator GI = M.global_begin(), E = M.global_end();
       GI != E; ++GI) {
    // We are going to delete llvm.global_ctors.
    // Therefore, don't instrument it.
    if (GI->getName() == "llvm.global_ctors")
      continue;
    // Prevent global variables from sharing the same address, because it
    // breaks the assumption that global variables do not alias.
    // The same goes to functions.
    if (GI->hasUnnamedAddr()) {
      GI->setUnnamedAddr(false);
    }
    uint64_t TypeSize = TD.getTypeStoreSize(GI->getType()->getElementType());
    instrumentMemoryAllocation(GI,
                               ConstantInt::get(LongType, TypeSize),
                               NULL,
                               Ret);
    instrumentPointer(GI, NULL, Ret);
  }

  for (Module::iterator F = M.begin(); F != M.end(); ++F) {
    // These hooks added by us don't have a value ID.
    if (MemAllocHook == F || MainArgsAllocHook == F || TopLevelHook == F ||
        AddrTakenHook == F || CallHook == F || ReturnHook == F ||
        GlobalsAllocHook == F || MemHooksIniter == F || AfterForkHook == F ||
        BeforeForkHook == F) {
      continue;
    }
    // InvalidID: maybe this is inserted by alias checker in hybrid mode.
    if (IDA.getValueID(F) == IDAssigner::InvalidID)
      continue;
    // Ignore intrinsic functions because we cannot take the address of
    // an intrinsic. Also, no function pointers will point to instrinsic
    // functions.
    if (F->isIntrinsic())
      continue;
    // Prevent functions from sharing the same address.
    if (F->hasUnnamedAddr()) {
      F->setUnnamedAddr(false);
    }
    uint64_t TypeSize = TD.getTypeStoreSize(F->getType());
    assert(TypeSize == TD.getPointerSize());
    instrumentMemoryAllocation(F,
                               ConstantInt::get(LongType, TypeSize),
                               NULL,
                               Ret);
    instrumentPointer(F, NULL, Ret);
  }
}

/// DisambiguateGlobalSymbols - Give anonymous global values names.
///
static void DisambiguateGlobalSymbols(Module *M) {
  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I)
    if (!I->hasName())
      I->setName("anon_global");
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    if (!I->hasName())
      I->setName("anon_fn");
}

void MemoryInstrumenter::checkFeatures(Module &M) {
    // Check whether any memory allocation function can
    // potentially be pointed by function pointers.
    // Also, all intrinsic functions will be called directly,
    // i.e. not via function pointers.
    for (Module::iterator F = M.begin(); F != M.end(); ++F) {
        if (DynAAUtils::IsMalloc(F) || F->isIntrinsic()) {
            for (Value::use_iterator UI = F->use_begin(); UI != F->use_end(); ++UI) {
                User *Usr = *UI;
                assert(isa<CallInst>(Usr) || isa<InvokeInst>(Usr));
                CallSite CS(cast<Instruction>(Usr));
                for (unsigned i = 0; i < CS.arg_size(); ++i)
                    assert(CS.getArgument(i) != F);
            }
        }
    }

    // Check whether memory allocation functions are captured.
    for (Module::iterator F = M.begin(); F != M.end(); ++F) {
        // 0 is the return, 1 is the first parameter.
        if (F->isDeclaration() && F->doesNotAlias(0) && !DynAAUtils::IsMalloc(F)) {
            errs().changeColor(raw_ostream::RED);
            errs() << F->getName() << "'s return value is marked noalias, ";
            errs() << "but the function is not treated as malloc.\n";
            errs().resetColor();
        }
    }

    // Global variables shouldn't be of the array type.
    for (Module::global_iterator GI = M.global_begin(), E = M.global_end();
            GI != E; ++GI) {
        assert(!GI->getType()->isArrayTy());
    }
    // A function parameter or an instruction can be an array, but we don't
    // instrument such constructs for now. Issue a warning on such cases.
    for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
        for (Function::arg_iterator AI = F->arg_begin(); AI != F->arg_end(); ++AI) {
            if (AI->getType()->isArrayTy()) {
                errs().changeColor(raw_ostream::RED);
                errs() << F->getName() << ":" << *AI << " is an array\n";
                errs().resetColor();
            }
        }
    }
    for (Module::iterator F = M.begin(); F != M.end(); ++F) {
        for (Function::iterator BB = F->begin(); BB != F->end(); ++BB) {
            for (BasicBlock::iterator Ins = BB->begin(); Ins != BB->end(); ++Ins) {
                if (Ins->getType()->isArrayTy()) {
                    errs().changeColor(raw_ostream::RED);
                    errs() << F->getName() << ":" << *Ins << " is an array\n";
                    errs().resetColor();
                }
            }
        }
    }
}

// dropAllReferences() - This function causes all the subelements to "let go"
// of all references that they are maintaining.  This allows one to 'delete' a
// whole module at a time, even though there may be circular references... first
// all references are dropped, and all use counts go to zero.  Then everything
// is deleted for real.  Note that no operations are valid on an object that
// has "dropped all references", except operator delete.
//
void Module::dropAllReferences() {
  for(Module::iterator I = begin(), E = end(); I != E; ++I)
    I->dropAllReferences();

  for(Module::global_iterator I = global_begin(), E = global_end(); I != E; ++I)
    I->dropAllReferences();

  for(Module::alias_iterator I = alias_begin(), E = alias_end(); I != E; ++I)
    I->dropAllReferences();
}

bool GlobalMerge::doInitialization(Module &M) {
  DenseMap<unsigned, SmallVector<GlobalVariable*, 16> > Globals, ConstGlobals,
                                                        BSSGlobals;
  const DataLayout *TD = TLI->getDataLayout();
  unsigned MaxOffset = TLI->getMaximalGlobalOffset();
  bool Changed = false;

  // Grab all non-const globals.
  for (Module::global_iterator I = M.global_begin(),
         E = M.global_end(); I != E; ++I) {
    // Merge is safe for "normal" internal globals only
    if (!I->hasLocalLinkage() || I->isThreadLocal() || I->hasSection())
      continue;

    PointerType *PT = dyn_cast<PointerType>(I->getType());
    assert(PT && "Global variable is not a pointer!");

    unsigned AddressSpace = PT->getAddressSpace();

    // Ignore fancy-aligned globals for now.
    unsigned Alignment = TD->getPreferredAlignment(I);
    Type *Ty = I->getType()->getElementType();
    if (Alignment > TD->getABITypeAlignment(Ty))
      continue;

    // Ignore all 'special' globals.
    if (I->getName().startswith("llvm.") ||
        I->getName().startswith(".llvm."))
      continue;

    if (TD->getTypeAllocSize(Ty) < MaxOffset) {
      if (TargetLoweringObjectFile::getKindForGlobal(I, TLI->getTargetMachine())
          .isBSSLocal())
        BSSGlobals[AddressSpace].push_back(I);
      else if (I->isConstant())
        ConstGlobals[AddressSpace].push_back(I);
      else
        Globals[AddressSpace].push_back(I);
    }
  }

  for (DenseMap<unsigned, SmallVector<GlobalVariable*, 16> >::iterator
       I = Globals.begin(), E = Globals.end(); I != E; ++I)
    if (I->second.size() > 1)
      Changed |= doMerge(I->second, M, false, I->first);

  for (DenseMap<unsigned, SmallVector<GlobalVariable*, 16> >::iterator
       I = BSSGlobals.begin(), E = BSSGlobals.end(); I != E; ++I)
    if (I->second.size() > 1)
      Changed |= doMerge(I->second, M, false, I->first);

  // FIXME: This currently breaks the EH processing due to way how the
  // typeinfo detection works. We might want to detect the TIs and ignore
  // them in the future.
  // if (ConstGlobals.size() > 1)
  //  Changed |= doMerge(ConstGlobals, M, true);

  return Changed;
}

void MemoryInstrumenter::checkFeatures(Module &M) {
  // Check whether any memory allocation function can
  // potentially be pointed by function pointers.
  // Also, all intrinsic functions will be called directly,
  // i.e. not via function pointers.
  for (Module::iterator F = M.begin(); F != M.end(); ++F) {
    if (DynAAUtils::IsMalloc(F) || F->isIntrinsic()) {
      for (Value::use_iterator UI = F->use_begin(); UI != F->use_end(); ++UI) {
        User *Usr = *UI;
        assert(isa<CallInst>(Usr) || isa<InvokeInst>(Usr));
        CallSite CS(cast<Instruction>(Usr));
        for (unsigned i = 0; i < CS.arg_size(); ++i)
          assert(CS.getArgument(i) != F);
      }
    }
  }

  // Check whether memory allocation functions are captured.
  for (Module::iterator F = M.begin(); F != M.end(); ++F) {
    // 0 is the return, 1 is the first parameter.
    if (F->isDeclaration() && F->doesNotAlias(0) && !DynAAUtils::IsMalloc(F)) {
      errs().changeColor(raw_ostream::RED);
      errs() << F->getName() << "'s return value is marked noalias, ";
      errs() << "but the function is not treated as malloc.\n";
      errs().resetColor();
    }
  }

  // Sequential types except pointer types shouldn't be used as the type of
  // an instruction, a function parameter, or a global variable.
  for (Module::global_iterator GI = M.global_begin(), E = M.global_end();
       GI != E; ++GI) {
    if (isa<SequentialType>(GI->getType()))
      assert(GI->getType()->isPointerTy());
  }
  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
    for (Function::arg_iterator AI = F->arg_begin(); AI != F->arg_end(); ++AI) {
      if (isa<SequentialType>(AI->getType()))
        assert(AI->getType()->isPointerTy());
    }
  }
  for (Module::iterator F = M.begin(); F != M.end(); ++F) {
    for (Function::iterator BB = F->begin(); BB != F->end(); ++BB) {
      for (BasicBlock::iterator Ins = BB->begin(); Ins != BB->end(); ++Ins) {
        if (isa<SequentialType>(Ins->getType()))
          assert(Ins->getType()->isPointerTy());
      }
    }
  }

  // We don't support multi-process programs for now.
  if (!HookFork)
    assert(M.getFunction("fork") == NULL);
}

/// doInitialization - Scan the list of globals and promote any with Private
/// linkage to use LinkerPrivate linkage instead.  Returns true if changed.
bool ARM64SetGlobalLinkage::doInitialization(Module &M) {
  bool Changed = false;

  for (Module::global_iterator I = M.global_begin(),
         E = M.global_end(); I != E; ++I) {
    if (I->hasPrivateLinkage()) {
      I->setLinkage(llvm::GlobalValue::LinkerPrivateLinkage);
      Changed = true;
    }
  }

  return Changed;
}

// Create shadow information for all global variables.
void LLPEAnalysisPass::initShadowGlobals(Module& M, uint32_t extraSlots) {

  uint32_t i = 0;
  uint32_t nGlobals = std::distance(M.global_begin(), M.global_end());
  // extraSlots are reserved for new globals we know will be introduced between now and specialisation start.
  nGlobals += extraSlots;
  shadowGlobals = new ShadowGV[nGlobals];

  // Assign them all numbers before computing initialisers, because the initialiser can
  // reference another global, and getValPB will then lookup in shadowGlobalsIdx.

  for(Module::global_iterator it = M.global_begin(), itend = M.global_end(); it != itend; ++it, ++i) {

    shadowGlobals[i].G = it;
    shadowGlobalsIdx[it] = i;

  }

  i = 0;
  for(Module::global_iterator it = M.global_begin(), itend = M.global_end(); it != itend; ++it, ++i) {

    // getTypeStoreSize can be expensive, so do it once here.
    if(it->isConstant()) {
      shadowGlobals[i].storeSize = GlobalAA->getTypeStoreSize(shadowGlobals[i].G->getType());
      continue;
    }

    // Non-constant global -- assign it a heap slot.
    shadowGlobals[i].allocIdx = (int32_t)heap.size();
    
    heap.push_back(AllocData());
    AllocData& AD = heap.back();
    AD.allocIdx = heap.size() - 1;
    AD.storeSize = GlobalAA->getTypeStoreSize(it->getType()->getElementType());
    AD.isCommitted = true;
    // This usually points to a malloc instruction -- here the global itself.
    AD.allocValue = ShadowValue(&(shadowGlobals[i]));
    AD.allocType = shadowGlobals[i].G->getType();

    //errs() << "Init store for " << *it << " -> ";
    //printPB(errs(), *Init);
    //errs() << "\n";

    shadowGlobals[i].storeSize = AD.storeSize;

  }

}