clang  15.0.0git
ObjCMissingSuperCallChecker.cpp
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1 //==- ObjCMissingSuperCallChecker.cpp - Check missing super-calls in ObjC --==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines a ObjCMissingSuperCallChecker, a checker that
10 // analyzes a UIViewController implementation to determine if it
11 // correctly calls super in the methods where this is mandatory.
12 //
13 //===----------------------------------------------------------------------===//
14 
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprObjC.h"
24 #include "llvm/ADT/SmallPtrSet.h"
25 #include "llvm/ADT/SmallString.h"
26 #include "llvm/Support/raw_ostream.h"
27 
28 using namespace clang;
29 using namespace ento;
30 
31 namespace {
32 struct SelectorDescriptor {
33  const char *SelectorName;
34  unsigned ArgumentCount;
35 };
36 
37 //===----------------------------------------------------------------------===//
38 // FindSuperCallVisitor - Identify specific calls to the superclass.
39 //===----------------------------------------------------------------------===//
40 
41 class FindSuperCallVisitor : public RecursiveASTVisitor<FindSuperCallVisitor> {
42 public:
43  explicit FindSuperCallVisitor(Selector S) : DoesCallSuper(false), Sel(S) {}
44 
45  bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
46  if (E->getSelector() == Sel)
48  DoesCallSuper = true;
49 
50  // Recurse if we didn't find the super call yet.
51  return !DoesCallSuper;
52  }
53 
54  bool DoesCallSuper;
55 
56 private:
57  Selector Sel;
58 };
59 
60 //===----------------------------------------------------------------------===//
61 // ObjCSuperCallChecker
62 //===----------------------------------------------------------------------===//
63 
64 class ObjCSuperCallChecker : public Checker<
65  check::ASTDecl<ObjCImplementationDecl> > {
66 public:
67  ObjCSuperCallChecker() : IsInitialized(false) {}
68 
69  void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager &Mgr,
70  BugReporter &BR) const;
71 private:
72  bool isCheckableClass(const ObjCImplementationDecl *D,
73  StringRef &SuperclassName) const;
74  void initializeSelectors(ASTContext &Ctx) const;
75  void fillSelectors(ASTContext &Ctx, ArrayRef<SelectorDescriptor> Sel,
76  StringRef ClassName) const;
77  mutable llvm::StringMap<llvm::SmallPtrSet<Selector, 16>> SelectorsForClass;
78  mutable bool IsInitialized;
79 };
80 
81 }
82 
83 /// Determine whether the given class has a superclass that we want
84 /// to check. The name of the found superclass is stored in SuperclassName.
85 ///
86 /// \param D The declaration to check for superclasses.
87 /// \param[out] SuperclassName On return, the found superclass name.
88 bool ObjCSuperCallChecker::isCheckableClass(const ObjCImplementationDecl *D,
89  StringRef &SuperclassName) const {
91  for ( ; ID ; ID = ID->getSuperClass())
92  {
93  SuperclassName = ID->getIdentifier()->getName();
94  if (SelectorsForClass.count(SuperclassName))
95  return true;
96  }
97  return false;
98 }
99 
100 void ObjCSuperCallChecker::fillSelectors(ASTContext &Ctx,
102  StringRef ClassName) const {
103  llvm::SmallPtrSet<Selector, 16> &ClassSelectors =
104  SelectorsForClass[ClassName];
105  // Fill the Selectors SmallSet with all selectors we want to check.
106  for (ArrayRef<SelectorDescriptor>::iterator I = Sel.begin(), E = Sel.end();
107  I != E; ++I) {
108  SelectorDescriptor Descriptor = *I;
109  assert(Descriptor.ArgumentCount <= 1); // No multi-argument selectors yet.
110 
111  // Get the selector.
112  IdentifierInfo *II = &Ctx.Idents.get(Descriptor.SelectorName);
113 
114  Selector Sel = Ctx.Selectors.getSelector(Descriptor.ArgumentCount, &II);
115  ClassSelectors.insert(Sel);
116  }
117 }
118 
119 void ObjCSuperCallChecker::initializeSelectors(ASTContext &Ctx) const {
120 
121  { // Initialize selectors for: UIViewController
122  const SelectorDescriptor Selectors[] = {
123  { "addChildViewController", 1 },
124  { "viewDidAppear", 1 },
125  { "viewDidDisappear", 1 },
126  { "viewWillAppear", 1 },
127  { "viewWillDisappear", 1 },
128  { "removeFromParentViewController", 0 },
129  { "didReceiveMemoryWarning", 0 },
130  { "viewDidUnload", 0 },
131  { "viewDidLoad", 0 },
132  { "viewWillUnload", 0 },
133  { "updateViewConstraints", 0 },
134  { "encodeRestorableStateWithCoder", 1 },
135  { "restoreStateWithCoder", 1 }};
136 
137  fillSelectors(Ctx, Selectors, "UIViewController");
138  }
139 
140  { // Initialize selectors for: UIResponder
141  const SelectorDescriptor Selectors[] = {
142  { "resignFirstResponder", 0 }};
143 
144  fillSelectors(Ctx, Selectors, "UIResponder");
145  }
146 
147  { // Initialize selectors for: NSResponder
148  const SelectorDescriptor Selectors[] = {
149  { "encodeRestorableStateWithCoder", 1 },
150  { "restoreStateWithCoder", 1 }};
151 
152  fillSelectors(Ctx, Selectors, "NSResponder");
153  }
154 
155  { // Initialize selectors for: NSDocument
156  const SelectorDescriptor Selectors[] = {
157  { "encodeRestorableStateWithCoder", 1 },
158  { "restoreStateWithCoder", 1 }};
159 
160  fillSelectors(Ctx, Selectors, "NSDocument");
161  }
162 
163  IsInitialized = true;
164 }
165 
166 void ObjCSuperCallChecker::checkASTDecl(const ObjCImplementationDecl *D,
167  AnalysisManager &Mgr,
168  BugReporter &BR) const {
169  ASTContext &Ctx = BR.getContext();
170 
171  // We need to initialize the selector table once.
172  if (!IsInitialized)
173  initializeSelectors(Ctx);
174 
175  // Find out whether this class has a superclass that we are supposed to check.
176  StringRef SuperclassName;
177  if (!isCheckableClass(D, SuperclassName))
178  return;
179 
180 
181  // Iterate over all instance methods.
182  for (auto *MD : D->instance_methods()) {
183  Selector S = MD->getSelector();
184  // Find out whether this is a selector that we want to check.
185  if (!SelectorsForClass[SuperclassName].count(S))
186  continue;
187 
188  // Check if the method calls its superclass implementation.
189  if (MD->getBody())
190  {
191  FindSuperCallVisitor Visitor(S);
192  Visitor.TraverseDecl(MD);
193 
194  // It doesn't call super, emit a diagnostic.
195  if (!Visitor.DoesCallSuper) {
196  PathDiagnosticLocation DLoc =
197  PathDiagnosticLocation::createEnd(MD->getBody(),
198  BR.getSourceManager(),
199  Mgr.getAnalysisDeclContext(D));
200 
201  const char *Name = "Missing call to superclass";
202  SmallString<320> Buf;
203  llvm::raw_svector_ostream os(Buf);
204 
205  os << "The '" << S.getAsString()
206  << "' instance method in " << SuperclassName.str() << " subclass '"
207  << *D << "' is missing a [super " << S.getAsString() << "] call";
208 
209  BR.EmitBasicReport(MD, this, Name, categories::CoreFoundationObjectiveC,
210  os.str(), DLoc);
211  }
212  }
213  }
214 }
215 
216 
217 //===----------------------------------------------------------------------===//
218 // Check registration.
219 //===----------------------------------------------------------------------===//
220 
221 void ento::registerObjCSuperCallChecker(CheckerManager &Mgr) {
222  Mgr.registerChecker<ObjCSuperCallChecker>();
223 }
224 
225 bool ento::shouldRegisterObjCSuperCallChecker(const CheckerManager &mgr) {
226  return true;
227 }
228 
229 /*
230  ToDo list for expanding this check in the future, the list is not exhaustive.
231  There are also cases where calling super is suggested but not "mandatory".
232  In addition to be able to check the classes and methods below, architectural
233  improvements like being able to allow for the super-call to be done in a called
234  method would be good too.
235 
236 UIDocument subclasses
237 - finishedHandlingError:recovered: (is multi-arg)
238 - finishedHandlingError:recovered: (is multi-arg)
239 
240 UIViewController subclasses
241 - loadView (should *never* call super)
242 - transitionFromViewController:toViewController:
243  duration:options:animations:completion: (is multi-arg)
244 
245 UICollectionViewController subclasses
246 - loadView (take care because UIViewController subclasses should NOT call super
247  in loadView, but UICollectionViewController subclasses should)
248 
249 NSObject subclasses
250 - doesNotRecognizeSelector (it only has to call super if it doesn't throw)
251 
252 UIPopoverBackgroundView subclasses (some of those are class methods)
253 - arrowDirection (should *never* call super)
254 - arrowOffset (should *never* call super)
255 - arrowBase (should *never* call super)
256 - arrowHeight (should *never* call super)
257 - contentViewInsets (should *never* call super)
258 
259 UITextSelectionRect subclasses (some of those are properties)
260 - rect (should *never* call super)
261 - range (should *never* call super)
262 - writingDirection (should *never* call super)
263 - isVertical (should *never* call super)
264 - containsStart (should *never* call super)
265 - containsEnd (should *never* call super)
266 */
clang::ObjCMessageExpr::SuperInstance
@ SuperInstance
The receiver is the instance of the superclass object.
Definition: ExprObjC.h:1097
clang::ObjCInterfaceDecl
Represents an ObjC class declaration.
Definition: DeclObjC.h:1150
clang::ObjCImplementationDecl
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2548
clang::ObjCMessageExpr::getSelector
Selector getSelector() const
Definition: ExprObjC.cpp:293
clang::ento::PathDiagnosticLocation::createEnd
static PathDiagnosticLocation createEnd(const Stmt *S, const SourceManager &SM, const LocationOrAnalysisDeclContext LAC)
Create a location for the end of the statement.
Definition: PathDiagnostic.cpp:594
clang::IdentifierTable::get
IdentifierInfo & get(StringRef Name)
Return the identifier token info for the specified named identifier.
Definition: IdentifierTable.h:596
clang::ObjCContainerDecl::instance_methods
instmeth_range instance_methods() const
Definition: DeclObjC.h:1029
llvm::SmallPtrSet
Definition: ASTContext.h:82
clang::ObjCImplDecl::getClassInterface
const ObjCInterfaceDecl * getClassInterface() const
Definition: DeclObjC.h:2436
DeclObjC.h
BuiltinCheckerRegistration.h
clang::SelectorTable::getSelector
Selector getSelector(unsigned NumArgs, IdentifierInfo **IIV)
Can create any sort of selector.
Definition: IdentifierTable.cpp:713
clang::ASTContext::Selectors
SelectorTable & Selectors
Definition: ASTContext.h:656
BugReporter.h
clang::ASTContext
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:208
clang::RecursiveASTVisitor
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
Definition: RecursiveASTVisitor.h:165
clang::ObjCMessageExpr::getReceiverKind
ReceiverKind getReceiverKind() const
Determine the kind of receiver that this message is being sent to.
Definition: ExprObjC.h:1224
Expr.h
llvm::SmallString
Definition: LLVM.h:37
PathDiagnostic.h
ExprObjC.h
clang::ObjCMessageExpr
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:940
clang::ento::categories::CoreFoundationObjectiveC
const char *const CoreFoundationObjectiveC
Definition: CommonBugCategories.cpp:16
false
#define false
Definition: stdbool.h:22
clang::ASTContext::Idents
IdentifierTable & Idents
Definition: ASTContext.h:655
llvm::ArrayRef
Definition: LLVM.h:34
clang::ObjCInterfaceDecl::getSuperClass
ObjCInterfaceDecl * getSuperClass() const
Definition: DeclObjC.cpp:351
clang::IdentifierInfo
One of these records is kept for each identifier that is lexed.
Definition: IdentifierTable.h:84
Checker.h
clang::Builtin::ID
ID
Definition: Builtins.h:52
clang
Definition: CalledOnceCheck.h:17
clang::Selector
Smart pointer class that efficiently represents Objective-C method names.
Definition: IdentifierTable.h:752
RecursiveASTVisitor.h
AnalysisManager.h