1 files changed, 291 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
new file mode 100644
index 0000000..133204a
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
@@ -0,0 +1,291 @@
+//==- 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 CheckObjCDealloc, a checker that
+//  analyzes an Objective-C class's implementation to determine if it
+//  correctly implements -dealloc.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "clang/AST/ExprObjC.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/Basic/LangOptions.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+static bool scan_dealloc(Stmt *S, Selector Dealloc) {
+
+  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S))
+    if (ME->getSelector() == Dealloc) {
+      switch (ME->getReceiverKind()) {
+      case ObjCMessageExpr::Instance: return false;
+      case ObjCMessageExpr::SuperInstance: return true;
+      case ObjCMessageExpr::Class: break;
+      case ObjCMessageExpr::SuperClass: break;
+      }
+    }
+
+  // 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;
+}
+
+static bool scan_ivar_release(Stmt *S, ObjCIvarDecl *ID,
+                              const ObjCPropertyDecl *PD,
+                              Selector Release,
+                              IdentifierInfo* SelfII,
+                              ASTContext &Ctx) {
+
+  // [mMyIvar release]
+  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S))
+    if (ME->getSelector() == Release)
+      if (ME->getInstanceReceiver())
+        if (Expr *Receiver = ME->getInstanceReceiver()->IgnoreParenCasts())
+          if (ObjCIvarRefExpr *E = dyn_cast<ObjCIvarRefExpr>(Receiver))
+            if (E->getDecl() == ID)
+              return true;
+
+  // [self setMyIvar:nil];
+  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S))
+    if (ME->getInstanceReceiver())
+      if (Expr *Receiver = ME->getInstanceReceiver()->IgnoreParenCasts())
+        if (DeclRefExpr *E = dyn_cast<DeclRefExpr>(Receiver))
+          if (E->getDecl()->getIdentifier() == SelfII)
+            if (ME->getMethodDecl() == PD->getSetterMethodDecl() &&
+                ME->getNumArgs() == 1 &&
+                ME->getArg(0)->isNullPointerConstant(Ctx, 
+                                              Expr::NPC_ValueDependentIsNull))
+              return true;
+
+  // self.myIvar = nil;
+  if (BinaryOperator* BO = dyn_cast<BinaryOperator>(S))
+    if (BO->isAssignmentOp())
+      if (ObjCPropertyRefExpr *PRE =
+           dyn_cast<ObjCPropertyRefExpr>(BO->getLHS()->IgnoreParenCasts()))
+        if (PRE->isExplicitProperty() && PRE->getExplicitProperty() == PD)
+            if (BO->getRHS()->isNullPointerConstant(Ctx, 
+                                            Expr::NPC_ValueDependentIsNull)) {
+              // This is only a 'release' if the property kind is not
+              // 'assign'.
+              return PD->getSetterKind() != ObjCPropertyDecl::Assign;;
+            }
+
+  // Recurse to children.
+  for (Stmt::child_iterator I = S->child_begin(), E= S->child_end(); I!=E; ++I)
+    if (*I && scan_ivar_release(*I, ID, PD, Release, SelfII, Ctx))
+      return true;
+
+  return false;
+}
+
+static void checkObjCDealloc(const ObjCImplementationDecl *D,
+                             const LangOptions& LOpts, BugReporter& BR) {
+
+  assert (LOpts.getGC() != LangOptions::GCOnly);
+
+  ASTContext &Ctx = BR.getContext();
+  const ObjCInterfaceDecl *ID = D->getClassInterface();
+
+  // Does the class contain any ivars that are pointers (or id<...>)?
+  // If not, skip the check entirely.
+  // NOTE: This is motivated by PR 2517:
+  //        http://llvm.org/bugs/show_bug.cgi?id=2517
+
+  bool containsPointerIvar = false;
+
+  for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(), E=ID->ivar_end();
+       I!=E; ++I) {
+
+    ObjCIvarDecl *ID = *I;
+    QualType T = ID->getType();
+
+    if (!T->isObjCObjectPointerType() ||
+        ID->getAttr<IBOutletAttr>() || // Skip IBOutlets.
+        ID->getAttr<IBOutletCollectionAttr>()) // Skip IBOutletCollections.
+      continue;
+
+    containsPointerIvar = true;
+    break;
+  }
+
+  if (!containsPointerIvar)
+    return;
+
+  // Determine if the class subclasses NSObject.
+  IdentifierInfo* NSObjectII = &Ctx.Idents.get("NSObject");
+  IdentifierInfo* SenTestCaseII = &Ctx.Idents.get("SenTestCase");
+
+
+  for ( ; ID ; ID = ID->getSuperClass()) {
+    IdentifierInfo *II = ID->getIdentifier();
+
+    if (II == NSObjectII)
+      break;
+
+    // FIXME: For now, ignore classes that subclass SenTestCase, as these don't
+    // need to implement -dealloc.  They implement tear down in another way,
+    // which we should try and catch later.
+    //  http://llvm.org/bugs/show_bug.cgi?id=3187
+    if (II == SenTestCaseII)
+      return;
+  }
+
+  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;
+    }
+  }
+
+  PathDiagnosticLocation DLoc =
+    PathDiagnosticLocation::createBegin(D, BR.getSourceManager());
+
+  if (!MD) { // No dealloc found.
+
+    const char* name = LOpts.getGC() == LangOptions::NonGC
+                       ? "missing -dealloc"
+                       : "missing -dealloc (Hybrid MM, non-GC)";
+
+    std::string buf;
+    llvm::raw_string_ostream os(buf);
+    os << "Objective-C class '" << *D << "' lacks a 'dealloc' instance method";
+
+    BR.EmitBasicReport(D, name, categories::CoreFoundationObjectiveC,
+                       os.str(), DLoc);
+    return;
+  }
+
+  // dealloc found.  Scan for missing [super dealloc].
+  if (MD->getBody() && !scan_dealloc(MD->getBody(), S)) {
+
+    const char* name = LOpts.getGC() == LangOptions::NonGC
+                       ? "missing [super dealloc]"
+                       : "missing [super dealloc] (Hybrid MM, non-GC)";
+
+    std::string buf;
+    llvm::raw_string_ostream os(buf);
+    os << "The 'dealloc' instance method in Objective-C class '" << *D
+       << "' does not send a 'dealloc' message to its super class"
+           " (missing [super dealloc])";
+
+    BR.EmitBasicReport(MD, name, categories::CoreFoundationObjectiveC,
+                       os.str(), DLoc);
+    return;
+  }
+
+  // Get the "release" selector.
+  IdentifierInfo* RII = &Ctx.Idents.get("release");
+  Selector RS = Ctx.Selectors.getSelector(0, &RII);
+
+  // Get the "self" identifier
+  IdentifierInfo* SelfII = &Ctx.Idents.get("self");
+
+  // Scan for missing and extra releases of ivars used by implementations
+  // of synthesized properties
+  for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(),
+       E = D->propimpl_end(); I!=E; ++I) {
+
+    // We can only check the synthesized properties
+    if ((*I)->getPropertyImplementation() != ObjCPropertyImplDecl::Synthesize)
+      continue;
+
+    ObjCIvarDecl *ID = (*I)->getPropertyIvarDecl();
+    if (!ID)
+      continue;
+
+    QualType T = ID->getType();
+    if (!T->isObjCObjectPointerType()) // Skip non-pointer ivars
+      continue;
+
+    const ObjCPropertyDecl *PD = (*I)->getPropertyDecl();
+    if (!PD)
+      continue;
+
+    // ivars cannot be set via read-only properties, so we'll skip them
+    if (PD->isReadOnly())
+      continue;
+
+    // ivar must be released if and only if the kind of setter was not 'assign'
+    bool requiresRelease = PD->getSetterKind() != ObjCPropertyDecl::Assign;
+    if (scan_ivar_release(MD->getBody(), ID, PD, RS, SelfII, Ctx)
+       != requiresRelease) {
+      const char *name = 0;
+      std::string buf;
+      llvm::raw_string_ostream os(buf);
+
+      if (requiresRelease) {
+        name = LOpts.getGC() == LangOptions::NonGC
+               ? "missing ivar release (leak)"
+               : "missing ivar release (Hybrid MM, non-GC)";
+
+        os << "The '" << *ID
+           << "' instance variable was retained by a synthesized property but "
+              "wasn't released in 'dealloc'";
+      } else {
+        name = LOpts.getGC() == LangOptions::NonGC
+               ? "extra ivar release (use-after-release)"
+               : "extra ivar release (Hybrid MM, non-GC)";
+
+        os << "The '" << *ID
+           << "' instance variable was not retained by a synthesized property "
+              "but was released in 'dealloc'";
+      }
+
+      PathDiagnosticLocation SDLoc =
+        PathDiagnosticLocation::createBegin((*I), BR.getSourceManager());
+
+      BR.EmitBasicReport(MD, name, categories::CoreFoundationObjectiveC,
+                         os.str(), SDLoc);
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// ObjCDeallocChecker
+//===----------------------------------------------------------------------===//
+
+namespace {
+class ObjCDeallocChecker : public Checker<
+                                      check::ASTDecl<ObjCImplementationDecl> > {
+public:
+  void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& mgr,
+                    BugReporter &BR) const {
+    if (mgr.getLangOpts().getGC() == LangOptions::GCOnly)
+      return;
+    checkObjCDealloc(cast<ObjCImplementationDecl>(D), mgr.getLangOpts(), BR);
+  }
+};
+}
+
+void ento::registerObjCDeallocChecker(CheckerManager &mgr) {
+  mgr.registerChecker<ObjCDeallocChecker>();
+}