Added static analysis check to see if a subclass of NSObject implements -dealloc, and whether or not that implementation calls [super dealloc].

llvm-svn: 53075

1 files changed, 118 insertions, 0 deletions

diff --git a/clang/lib/Analysis/CheckObjCDealloc.cpp b/clang/lib/Analysis/CheckObjCDealloc.cpp
new file mode 100644
index 00000000000..9a40fa97ec2
--- /dev/null
+++ b/clang/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);
+  }    
+}
+