Added static analysis check to see if a subclass of NSObject implements -dealloc, and whether or not that implementation calls [super dealloc].
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@53075 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/CheckObjCDealloc.cpp b/lib/Analysis/CheckObjCDealloc.cpp
new file mode 100644
index 0000000..9a40fa9
--- /dev/null
+++ b/lib/Analysis/CheckObjCDealloc.cpp
@@ -0,0 +1,118 @@
+//==- CheckObjCDealloc.cpp - Check ObjC -dealloc implementation --*- 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 DeadStores, a flow-sensitive checker that looks for
+// stores to variables that are no longer live.
+//
+//===----------------------------------------------------------------------===//
+
+#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 <sstream>
+
+using namespace clang;
+
+static bool scan_dealloc(Stmt* S, Selector Dealloc) {
+
+ if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
+ if (ME->getSelector() == Dealloc)
+ if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
+ if (PreDefinedExpr* E = dyn_cast<PreDefinedExpr>(Receiver))
+ if (E->getIdentType() == PreDefinedExpr::ObjCSuper)
+ return true;
+
+ // Recurse to children.
+
+ for (Stmt::child_iterator I = S->child_begin(), E= S->child_end(); I!=E; ++I)
+ if (*I && scan_dealloc(*I, Dealloc))
+ return true;
+
+ return false;
+}
+
+void clang::CheckObjCDealloc(ObjCImplementationDecl* D, BugReporter& BR) {
+
+ ASTContext& Ctx = BR.getContext();
+
+ // Determine if the class subclasses NSObject.
+ IdentifierInfo* NSObjectII = &Ctx.Idents.get("NSObject");
+ ObjCInterfaceDecl* ID = D->getClassInterface();
+
+ for ( ; ID ; ID = ID->getSuperClass())
+ if (ID->getIdentifier() == NSObjectII)
+ break;
+
+ if (!ID)
+ return;
+
+ // Get the "dealloc" selector.
+ IdentifierInfo* II = &Ctx.Idents.get("dealloc");
+ Selector S = Ctx.Selectors.getSelector(0, &II);
+
+ ObjCMethodDecl* MD = 0;
+
+ // Scan the instance methods for "dealloc".
+ for (ObjCImplementationDecl::instmeth_iterator I = D->instmeth_begin(),
+ E = D->instmeth_end(); I!=E; ++I) {
+
+ if ((*I)->getSelector() == S) {
+ MD = *I;
+ break;
+ }
+ }
+
+ if (!MD) { // No dealloc found.
+
+ // FIXME: This code should be reduced to three lines if possible (Refactor).
+ SimpleBugType BT("missing -dealloc");
+ DiagCollector C(BT);
+
+ std::ostringstream os;
+ os << "Objective-C class '" << D->getName()
+ << "' lacks a 'dealloc' instance method";
+
+ Diagnostic& Diag = BR.getDiagnostic();
+ Diag.Report(&C,
+ Ctx.getFullLoc(D->getLocStart()),
+ Diag.getCustomDiagID(Diagnostic::Warning, os.str().c_str()),
+ NULL, 0, NULL, 0);
+
+ for (DiagCollector::iterator I = C.begin(), E = C.end(); I != E; ++I)
+ BR.EmitWarning(*I);
+
+ return;
+ }
+
+ // dealloc found. Scan for missing [super dealloc].
+ if (MD->getBody() && !scan_dealloc(MD->getBody(), S)) {
+
+ // FIXME: This code should be reduced to three lines if possible (Refactor).
+ SimpleBugType BT("missing [super dealloc]");
+ DiagCollector C(BT);
+
+ std::ostringstream os;
+ os << "The 'dealloc' instance method in Objective-C class '" << D->getName()
+ << "' does not send a 'dealloc' message to it super class"
+ " (missing [super dealloc])";
+
+ Diagnostic& Diag = BR.getDiagnostic();
+ Diag.Report(&C,
+ Ctx.getFullLoc(MD->getLocStart()),
+ Diag.getCustomDiagID(Diagnostic::Warning, os.str().c_str()),
+ NULL, 0, NULL, 0);
+
+ for (DiagCollector::iterator I = C.begin(), E = C.end(); I != E; ++I)
+ BR.EmitWarning(*I);
+ }
+}
+