1 //==- ObjCMissingSuperCallChecker.cpp - Check missing super-calls in ObjC --==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines a ObjCMissingSuperCallChecker, a checker that
11 // analyzes a UIViewController implementation to determine if it
12 // correctly calls super in the methods where this is mandatory.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "ClangSACheckers.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprObjC.h"
20 #include "clang/AST/RecursiveASTVisitor.h"
21 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
22 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
23 #include "clang/StaticAnalyzer/Core/Checker.h"
24 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
25 #include "llvm/ADT/SmallSet.h"
26 #include "llvm/ADT/SmallString.h"
27 #include "llvm/Support/raw_ostream.h"
28
29 using namespace clang;
30 using namespace ento;
31
32 namespace {
33 struct SelectorDescriptor {
34 const char *SelectorName;
35 unsigned ArgumentCount;
36 };
37 }
38
39 //===----------------------------------------------------------------------===//
40 // FindSuperCallVisitor - Identify specific calls to the superclass.
41 //===----------------------------------------------------------------------===//
42
43 class FindSuperCallVisitor : public RecursiveASTVisitor<FindSuperCallVisitor> {
44 public:
FindSuperCallVisitor(Selector S)45 explicit FindSuperCallVisitor(Selector S) : DoesCallSuper(false), Sel(S) {}
46
VisitObjCMessageExpr(ObjCMessageExpr * E)47 bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
48 if (E->getSelector() == Sel)
49 if (E->getReceiverKind() == ObjCMessageExpr::SuperInstance)
50 DoesCallSuper = true;
51
52 // Recurse if we didn't find the super call yet.
53 return !DoesCallSuper;
54 }
55
56 bool DoesCallSuper;
57
58 private:
59 Selector Sel;
60 };
61
62 //===----------------------------------------------------------------------===//
63 // ObjCSuperCallChecker
64 //===----------------------------------------------------------------------===//
65
66 namespace {
67 class ObjCSuperCallChecker : public Checker<
68 check::ASTDecl<ObjCImplementationDecl> > {
69 public:
ObjCSuperCallChecker()70 ObjCSuperCallChecker() : IsInitialized(false) {}
71
72 void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager &Mgr,
73 BugReporter &BR) const;
74 private:
75 bool isCheckableClass(const ObjCImplementationDecl *D,
76 StringRef &SuperclassName) const;
77 void initializeSelectors(ASTContext &Ctx) const;
78 void fillSelectors(ASTContext &Ctx, ArrayRef<SelectorDescriptor> Sel,
79 StringRef ClassName) const;
80 mutable llvm::StringMap<llvm::SmallSet<Selector, 16> > SelectorsForClass;
81 mutable bool IsInitialized;
82 };
83
84 }
85
86 /// \brief Determine whether the given class has a superclass that we want
87 /// to check. The name of the found superclass is stored in SuperclassName.
88 ///
89 /// \param D The declaration to check for superclasses.
90 /// \param[out] SuperclassName On return, the found superclass name.
isCheckableClass(const ObjCImplementationDecl * D,StringRef & SuperclassName) const91 bool ObjCSuperCallChecker::isCheckableClass(const ObjCImplementationDecl *D,
92 StringRef &SuperclassName) const {
93 const ObjCInterfaceDecl *ID = D->getClassInterface();
94 for ( ; ID ; ID = ID->getSuperClass())
95 {
96 SuperclassName = ID->getIdentifier()->getName();
97 if (SelectorsForClass.count(SuperclassName))
98 return true;
99 }
100 return false;
101 }
102
fillSelectors(ASTContext & Ctx,ArrayRef<SelectorDescriptor> Sel,StringRef ClassName) const103 void ObjCSuperCallChecker::fillSelectors(ASTContext &Ctx,
104 ArrayRef<SelectorDescriptor> Sel,
105 StringRef ClassName) const {
106 llvm::SmallSet<Selector, 16> &ClassSelectors = SelectorsForClass[ClassName];
107 // Fill the Selectors SmallSet with all selectors we want to check.
108 for (ArrayRef<SelectorDescriptor>::iterator I = Sel.begin(), E = Sel.end();
109 I != E; ++I) {
110 SelectorDescriptor Descriptor = *I;
111 assert(Descriptor.ArgumentCount <= 1); // No multi-argument selectors yet.
112
113 // Get the selector.
114 IdentifierInfo *II = &Ctx.Idents.get(Descriptor.SelectorName);
115
116 Selector Sel = Ctx.Selectors.getSelector(Descriptor.ArgumentCount, &II);
117 ClassSelectors.insert(Sel);
118 }
119 }
120
initializeSelectors(ASTContext & Ctx) const121 void ObjCSuperCallChecker::initializeSelectors(ASTContext &Ctx) const {
122
123 { // Initialize selectors for: UIViewController
124 const SelectorDescriptor Selectors[] = {
125 { "addChildViewController", 1 },
126 { "viewDidAppear", 1 },
127 { "viewDidDisappear", 1 },
128 { "viewWillAppear", 1 },
129 { "viewWillDisappear", 1 },
130 { "removeFromParentViewController", 0 },
131 { "didReceiveMemoryWarning", 0 },
132 { "viewDidUnload", 0 },
133 { "viewDidLoad", 0 },
134 { "viewWillUnload", 0 },
135 { "updateViewConstraints", 0 },
136 { "encodeRestorableStateWithCoder", 1 },
137 { "restoreStateWithCoder", 1 }};
138
139 fillSelectors(Ctx, Selectors, "UIViewController");
140 }
141
142 { // Initialize selectors for: UIResponder
143 const SelectorDescriptor Selectors[] = {
144 { "resignFirstResponder", 0 }};
145
146 fillSelectors(Ctx, Selectors, "UIResponder");
147 }
148
149 { // Initialize selectors for: NSResponder
150 const SelectorDescriptor Selectors[] = {
151 { "encodeRestorableStateWithCoder", 1 },
152 { "restoreStateWithCoder", 1 }};
153
154 fillSelectors(Ctx, Selectors, "NSResponder");
155 }
156
157 { // Initialize selectors for: NSDocument
158 const SelectorDescriptor Selectors[] = {
159 { "encodeRestorableStateWithCoder", 1 },
160 { "restoreStateWithCoder", 1 }};
161
162 fillSelectors(Ctx, Selectors, "NSDocument");
163 }
164
165 IsInitialized = true;
166 }
167
checkASTDecl(const ObjCImplementationDecl * D,AnalysisManager & Mgr,BugReporter & BR) const168 void ObjCSuperCallChecker::checkASTDecl(const ObjCImplementationDecl *D,
169 AnalysisManager &Mgr,
170 BugReporter &BR) const {
171 ASTContext &Ctx = BR.getContext();
172
173 // We need to initialize the selector table once.
174 if (!IsInitialized)
175 initializeSelectors(Ctx);
176
177 // Find out whether this class has a superclass that we are supposed to check.
178 StringRef SuperclassName;
179 if (!isCheckableClass(D, SuperclassName))
180 return;
181
182
183 // Iterate over all instance methods.
184 for (auto *MD : D->instance_methods()) {
185 Selector S = MD->getSelector();
186 // Find out whether this is a selector that we want to check.
187 if (!SelectorsForClass[SuperclassName].count(S))
188 continue;
189
190 // Check if the method calls its superclass implementation.
191 if (MD->getBody())
192 {
193 FindSuperCallVisitor Visitor(S);
194 Visitor.TraverseDecl(MD);
195
196 // It doesn't call super, emit a diagnostic.
197 if (!Visitor.DoesCallSuper) {
198 PathDiagnosticLocation DLoc =
199 PathDiagnosticLocation::createEnd(MD->getBody(),
200 BR.getSourceManager(),
201 Mgr.getAnalysisDeclContext(D));
202
203 const char *Name = "Missing call to superclass";
204 SmallString<320> Buf;
205 llvm::raw_svector_ostream os(Buf);
206
207 os << "The '" << S.getAsString()
208 << "' instance method in " << SuperclassName.str() << " subclass '"
209 << *D << "' is missing a [super " << S.getAsString() << "] call";
210
211 BR.EmitBasicReport(MD, this, Name, categories::CoreFoundationObjectiveC,
212 os.str(), DLoc);
213 }
214 }
215 }
216 }
217
218
219 //===----------------------------------------------------------------------===//
220 // Check registration.
221 //===----------------------------------------------------------------------===//
222
registerObjCSuperCallChecker(CheckerManager & Mgr)223 void ento::registerObjCSuperCallChecker(CheckerManager &Mgr) {
224 Mgr.registerChecker<ObjCSuperCallChecker>();
225 }
226
227
228 /*
229 ToDo list for expanding this check in the future, the list is not exhaustive.
230 There are also cases where calling super is suggested but not "mandatory".
231 In addition to be able to check the classes and methods below, architectural
232 improvements like being able to allow for the super-call to be done in a called
233 method would be good too.
234
235 UIDocument subclasses
236 - finishedHandlingError:recovered: (is multi-arg)
237 - finishedHandlingError:recovered: (is multi-arg)
238
239 UIViewController subclasses
240 - loadView (should *never* call super)
241 - transitionFromViewController:toViewController:
242 duration:options:animations:completion: (is multi-arg)
243
244 UICollectionViewController subclasses
245 - loadView (take care because UIViewController subclasses should NOT call super
246 in loadView, but UICollectionViewController subclasses should)
247
248 NSObject subclasses
249 - doesNotRecognizeSelector (it only has to call super if it doesn't throw)
250
251 UIPopoverBackgroundView subclasses (some of those are class methods)
252 - arrowDirection (should *never* call super)
253 - arrowOffset (should *never* call super)
254 - arrowBase (should *never* call super)
255 - arrowHeight (should *never* call super)
256 - contentViewInsets (should *never* call super)
257
258 UITextSelectionRect subclasses (some of those are properties)
259 - rect (should *never* call super)
260 - range (should *never* call super)
261 - writingDirection (should *never* call super)
262 - isVertical (should *never* call super)
263 - containsStart (should *never* call super)
264 - containsEnd (should *never* call super)
265 */
266