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