| //==- CheckObjCUnusedIVars.cpp - Check for unused ivars ----------*- C++ -*-==// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines a CheckObjCUnusedIvars, a checker that |
| // analyzes an Objective-C class's interface/implementation to determine if it |
| // has any ivars that are never accessed. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/LocalCheckers.h" |
| #include "clang/Analysis/PathDiagnostic.h" |
| #include "clang/Analysis/PathSensitive/BugReporter.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/DeclObjC.h" |
| #include "clang/Basic/LangOptions.h" |
| |
| using namespace clang; |
| |
| enum IVarState { Unused, Used }; |
| typedef llvm::DenseMap<const ObjCIvarDecl*,IVarState> IvarUsageMap; |
| |
| static void Scan(IvarUsageMap& M, const Stmt* S) { |
| if (!S) |
| return; |
| |
| if (const ObjCIvarRefExpr *Ex = dyn_cast<ObjCIvarRefExpr>(S)) { |
| const ObjCIvarDecl *D = Ex->getDecl(); |
| IvarUsageMap::iterator I = M.find(D); |
| if (I != M.end()) |
| I->second = Used; |
| return; |
| } |
| |
| // Blocks can reference an instance variable of a class. |
| if (const BlockExpr *BE = dyn_cast<BlockExpr>(S)) { |
| Scan(M, BE->getBody()); |
| return; |
| } |
| |
| for (Stmt::const_child_iterator I=S->child_begin(),E=S->child_end(); I!=E;++I) |
| Scan(M, *I); |
| } |
| |
| static void Scan(IvarUsageMap& M, const ObjCPropertyImplDecl* D) { |
| if (!D) |
| return; |
| |
| const ObjCIvarDecl* ID = D->getPropertyIvarDecl(); |
| |
| if (!ID) |
| return; |
| |
| IvarUsageMap::iterator I = M.find(ID); |
| if (I != M.end()) |
| I->second = Used; |
| } |
| |
| void clang::CheckObjCUnusedIvar(ObjCImplementationDecl* D, BugReporter& BR) { |
| |
| const ObjCInterfaceDecl* ID = D->getClassInterface(); |
| IvarUsageMap M; |
| |
| // Iterate over the ivars. |
| for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(), |
| E=ID->ivar_end(); I!=E; ++I) { |
| |
| const ObjCIvarDecl* ID = *I; |
| |
| // Ignore ivars that aren't private. |
| if (ID->getAccessControl() != ObjCIvarDecl::Private) |
| continue; |
| |
| // Skip IB Outlets. |
| if (ID->getAttr<IBOutletAttr>()) |
| continue; |
| |
| M[ID] = Unused; |
| } |
| |
| if (M.empty()) |
| return; |
| |
| // Now scan the methods for accesses. |
| for (ObjCImplementationDecl::instmeth_iterator I = D->instmeth_begin(), |
| E = D->instmeth_end(); I!=E; ++I) |
| Scan(M, (*I)->getBody()); |
| |
| // Scan for @synthesized property methods that act as setters/getters |
| // to an ivar. |
| for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(), |
| E = D->propimpl_end(); I!=E; ++I) |
| Scan(M, *I); |
| |
| // Find ivars that are unused. |
| for (IvarUsageMap::iterator I = M.begin(), E = M.end(); I!=E; ++I) |
| if (I->second == Unused) { |
| std::string sbuf; |
| llvm::raw_string_ostream os(sbuf); |
| os << "Instance variable '" << I->first->getNameAsString() |
| << "' in class '" << ID->getNameAsString() |
| << "' is never used by the methods in its @implementation " |
| "(although it may be used by category methods)."; |
| |
| BR.EmitBasicReport("Unused instance variable", "Optimization", |
| os.str().c_str(), I->first->getLocation()); |
| } |
| } |