1 files changed, 111 insertions, 0 deletions
diff --git a/lib/Analysis/CheckObjCUnusedIVars.cpp b/lib/Analysis/CheckObjCUnusedIVars.cpp
new file mode 100644
index 0000000..7979f9c
--- /dev/null
+++ b/lib/Analysis/CheckObjCUnusedIVars.cpp
@@ -0,0 +1,111 @@
+//==- 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"
+#include <sstream>
+
+using namespace clang;
+
+enum IVarState { Unused, Used };
+typedef llvm::DenseMap<ObjCIvarDecl*,IVarState> IvarUsageMap;
+
+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, 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;
+}
+
+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());
+    }
+}
+