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;
}
if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(S))
for (PseudoObjectExpr::const_semantics_iterator
i = POE->semantics_begin(), e = POE->semantics_end(); i != e; ++i) {
const Expr *sub = *i;
if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(sub))
sub = OVE->getSourceExpr();
Scan(M, sub);
}
for (Stmt::const_child_iterator I=S->child_begin(),E=S->child_end(); I!=E;++I)
Scan(M, *I);
}
void clang::CheckObjCUnusedIvar(ObjCImplementationDecl* D, BugReporter& BR) {
ObjCInterfaceDecl* ID = D->getClassInterface();
IvarUsageMap M;
ASTContext &Ctx = BR.getContext();
// Iterate over the ivars.
for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(), E=ID->ivar_end();
I!=E; ++I) {
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(Ctx),
E = D->instmeth_end(Ctx); I!=E; ++I)
Scan(M, (*I)->getBody(Ctx));
// Scan for @synthesized property methods that act as setters/getters
// to an ivar.
for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(Ctx),
E = D->propimpl_end(Ctx); 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::ostringstream os;
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());
}
}
static void Scan(IvarUsageMap& M, ObjCPropertyImplDecl* D) {
if (!D)
return;
ObjCIvarDecl* ID = D->getPropertyIvarDecl();
if (!ID)
return;
IvarUsageMap::iterator I = M.find(ID);
if (I != M.end()) I->second = Used;
}
static void Scan(IvarUsageMap& M, Stmt* S) {
if (!S)
return;
if (ObjCIvarRefExpr* Ex = dyn_cast<ObjCIvarRefExpr>(S)) {
ObjCIvarDecl* D = Ex->getDecl();
IvarUsageMap::iterator I = M.find(D);
if (I != M.end()) I->second = Used;
return;
}
for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I)
Scan(M, *I);
}
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 checkObjCUnusedIvar(const 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...
// (a) aren't private
// (b) explicitly marked unused
// (c) are iboutlets
// (d) are unnamed bitfields
if (ID->getAccessControl() != ObjCIvarDecl::Private ||
ID->getAttr<UnusedAttr>() || ID->getAttr<IBOutletAttr>() ||
ID->getAttr<IBOutletCollectionAttr>() ||
ID->isUnnamedBitfield())
continue;
M[ID] = Unused;
}
if (M.empty())
return;
// Now scan the implementation declaration.
Scan(M, D);
// Any potentially unused ivars?
bool hasUnused = false;
for (IvarUsageMap::iterator I = M.begin(), E = M.end(); I!=E; ++I)
if (I->second == Unused) {
hasUnused = true;
break;
}
if (!hasUnused)
return;
// We found some potentially unused ivars. Scan the entire translation unit
// for functions inside the @implementation that reference these ivars.
// FIXME: In the future hopefully we can just use the lexical DeclContext
// to go from the ObjCImplementationDecl to the lexically "nested"
// C functions.
SourceManager &SM = BR.getSourceManager();
Scan(M, D->getDeclContext(), SM.getFileID(D->getLocation()), SM);
// 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 << "' in class '" << *ID
<< "' is never used by the methods in its @implementation "
"(although it may be used by category methods).";
PathDiagnosticLocation L =
PathDiagnosticLocation::create(I->first, BR.getSourceManager());
BR.EmitBasicReport(D, "Unused instance variable", "Optimization",
os.str(), L);
}
}
