[analyzer] Add an experimental ObjC direct ivar assignment checker.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164790 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 178 insertions, 0 deletions

diff --git a/lib/StaticAnalyzer/Checkers/DirectIvarAssignment.cpp b/lib/StaticAnalyzer/Checkers/DirectIvarAssignment.cpp
new file mode 100644
index 0000000000..db3a885350
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/DirectIvarAssignment.cpp
@@ -0,0 +1,178 @@
+//=- DirectIvarAssignment.cpp - Check rules on ObjC properties -*- C++ ----*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  Check that Objective C properties follow the following rules:
+//    - The property should be set with the setter, not though a direct
+//      assignment.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/StmtVisitor.h"
+#include "llvm/ADT/DenseMap.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class DirectIvarAssignment :
+  public Checker<check::ASTDecl<ObjCImplementationDecl> > {
+
+  typedef llvm::DenseMap<const ObjCIvarDecl*,
+                         const ObjCPropertyDecl*> IvarToPropertyMapTy;
+
+  /// A helper class, which walks the AST and locates all assignments to ivars
+  /// in the given function.
+  class MethodCrawler : public ConstStmtVisitor<MethodCrawler> {
+    const IvarToPropertyMapTy &IvarToPropMap;
+    const ObjCMethodDecl *MD;
+    const ObjCInterfaceDecl *InterfD;
+    BugReporter &BR;
+    LocationOrAnalysisDeclContext DCtx;
+
+  public:
+    MethodCrawler(const IvarToPropertyMapTy &InMap, const ObjCMethodDecl *InMD,
+        const ObjCInterfaceDecl *InID,
+        BugReporter &InBR, AnalysisDeclContext *InDCtx)
+    : IvarToPropMap(InMap), MD(InMD), InterfD(InID), BR(InBR), DCtx(InDCtx) {}
+
+    void VisitStmt(const Stmt *S) { VisitChildren(S); }
+
+    void VisitBinaryOperator(const BinaryOperator *BO);
+
+    void VisitChildren(const Stmt *S) {
+      for (Stmt::const_child_range I = S->children(); I; ++I)
+        if (*I)
+         this->Visit(*I);
+    }
+  };
+
+public:
+  void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& Mgr,
+                    BugReporter &BR) const;
+};
+
+static const ObjCIvarDecl *findPropertyBackingIvar(const ObjCPropertyDecl *PD,
+                                                   ObjCInterfaceDecl *InterD,
+                                            ASTContext &Ctx) {
+  // Check for synthesized ivars.
+  ObjCIvarDecl *ID = PD->getPropertyIvarDecl();
+  if (ID)
+    return ID;
+
+  // Check for existing "_PropName".
+  ID = InterD->lookupInstanceVariable(PD->getDefaultSynthIvarName(Ctx));
+  if (ID)
+    return ID;
+
+  // Check for existing "PropName".
+  IdentifierInfo *PropIdent = PD->getIdentifier();
+  ID = InterD->lookupInstanceVariable(PropIdent);
+
+  return ID;
+}
+
+void DirectIvarAssignment::checkASTDecl(const ObjCImplementationDecl *D,
+                                       AnalysisManager& Mgr,
+                                       BugReporter &BR) const {
+  const ObjCInterfaceDecl *InterD = D->getClassInterface();
+
+
+  IvarToPropertyMapTy IvarToPropMap;
+
+  // Find all properties for this class.
+  for (ObjCInterfaceDecl::prop_iterator I = InterD->prop_begin(),
+      E = InterD->prop_end(); I != E; ++I) {
+    ObjCPropertyDecl *PD = *I;
+
+    // Find the corresponding IVar.
+    const ObjCIvarDecl *ID = findPropertyBackingIvar(PD,
+                               const_cast<ObjCInterfaceDecl*>(InterD),
+                               Mgr.getASTContext());
+
+    if (!ID)
+      continue;
+
+    // Store the IVar to property mapping.
+    IvarToPropMap[ID] = PD;
+  }
+
+  if (IvarToPropMap.empty())
+    return;
+
+  for (ObjCImplementationDecl::instmeth_iterator I = D->instmeth_begin(),
+      E = D->instmeth_end(); I != E; ++I) {
+
+    ObjCMethodDecl *M = *I;
+    AnalysisDeclContext *DCtx = Mgr.getAnalysisDeclContext(M);
+
+    if (M->getMethodFamily() == OMF_init ||
+        M->getMethodFamily() == OMF_dealloc ||
+        M->getSelector().getAsString().find("init") != StringRef::npos ||
+        M->getSelector().getAsString().find("Init") != StringRef::npos)
+      continue;
+
+    const Stmt *Body = M->getBody();
+    if (!Body)
+      continue;
+
+    MethodCrawler MC(IvarToPropMap, M->getCanonicalDecl(), InterD, BR, DCtx);
+    MC.VisitStmt(Body);
+  }
+}
+
+void DirectIvarAssignment::MethodCrawler::VisitBinaryOperator(
+                                                    const BinaryOperator *BO) {
+  if (!BO->isAssignmentOp())
+    return;
+
+  const ObjCIvarRefExpr *IvarRef = dyn_cast<ObjCIvarRefExpr>(BO->getLHS());
+
+  if (!IvarRef)
+    return;
+
+  if (const ObjCIvarDecl *D = IvarRef->getDecl()) {
+    IvarToPropertyMapTy::const_iterator I = IvarToPropMap.find(D);
+    if (I != IvarToPropMap.end()) {
+      const ObjCPropertyDecl *PD = I->second;
+
+      ObjCMethodDecl *GetterMethod =
+          InterfD->getInstanceMethod(PD->getGetterName());
+      ObjCMethodDecl *SetterMethod =
+          InterfD->getInstanceMethod(PD->getSetterName());
+
+      if (SetterMethod && SetterMethod->getCanonicalDecl() == MD)
+        return;
+
+      if (GetterMethod && GetterMethod->getCanonicalDecl() == MD)
+        return;
+
+
+      PathDiagnosticLocation IvarRefLocation =
+          PathDiagnosticLocation::createBegin(IvarRef,
+              BR.getSourceManager(), DCtx);
+
+      BR.EmitBasicReport(MD,
+          "Property access",
+          categories::CoreFoundationObjectiveC,
+          "Direct assignment to an instance variable backing a property; "
+          "use the setter instead", IvarRefLocation);
+    }
+  }
+}
+}
+
+void ento::registerDirectIvarAssignment(CheckerManager &mgr) {
+  mgr.registerChecker<DirectIvarAssignment>();
+}