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//=- 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,
const ObjCInterfaceDecl *InterD,
ASTContext &Ctx) {
// Check for synthesized ivars.
ObjCIvarDecl *ID = PD->getPropertyIvarDecl();
if (ID)
return ID;
ObjCInterfaceDecl *NonConstInterD = const_cast<ObjCInterfaceDecl*>(InterD);
// Check for existing "_PropName".
ID = NonConstInterD->lookupInstanceVariable(PD->getDefaultSynthIvarName(Ctx));
if (ID)
return ID;
// Check for existing "PropName".
IdentifierInfo *PropIdent = PD->getIdentifier();
ID = NonConstInterD->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, 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);
// Skip the init, dealloc functions and any functions that might be doing
// initialization based on their name.
if (M->getMethodFamily() == OMF_init ||
M->getMethodFamily() == OMF_dealloc ||
M->getMethodFamily() == OMF_copy ||
M->getMethodFamily() == OMF_mutableCopy ||
M->getSelector().getNameForSlot(0).find("init") != StringRef::npos ||
M->getSelector().getNameForSlot(0).find("Init") != StringRef::npos)
continue;
const Stmt *Body = M->getBody();
assert(Body);
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()->IgnoreParenCasts());
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;
BR.EmitBasicReport(MD,
"Property access",
categories::CoreFoundationObjectiveC,
"Direct assignment to an instance variable backing a property; "
"use the setter instead", PathDiagnosticLocation(IvarRef,
BR.getSourceManager(),
DCtx));
}
}
}
}
void ento::registerDirectIvarAssignment(CheckerManager &mgr) {
mgr.registerChecker<DirectIvarAssignment>();
}
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