1 //= CheckerDocumentation.cpp - Documentation checker ---------------*- C++ -*-//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This checker lists all the checker callbacks and provides documentation for
13 //===----------------------------------------------------------------------===//
15 #include "ClangSACheckers.h"
16 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
17 #include "clang/StaticAnalyzer/Core/Checker.h"
18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
22 using namespace clang;
25 // All checkers should be placed into anonymous namespace.
26 // We place the CheckerDocumentation inside ento namespace to make the
27 // it visible in doxygen.
31 /// This checker documents the callback functions checkers can use to implement
32 /// the custom handling of the specific events during path exploration as well
33 /// as reporting bugs. Most of the callbacks are targeted at path-sensitive
36 /// \sa CheckerContext
37 class CheckerDocumentation : public Checker< check::PreStmt<ReturnStmt>,
38 check::PostStmt<DeclStmt>,
39 check::PreObjCMessage,
40 check::PostObjCMessage,
41 check::ObjCMessageNil,
44 check::BranchCondition,
50 check::EndOfTranslationUnit,
56 check::ConstPointerEscape,
57 check::Event<ImplicitNullDerefEvent>,
58 check::ASTDecl<FunctionDecl> > {
61 /// \brief Pre-visit the Statement.
63 /// The method will be called before the analyzer core processes the
64 /// statement. The notification is performed for every explored CFGElement,
65 /// which does not include the control flow statements such as IfStmt. The
66 /// callback can be specialized to be called with any subclass of Stmt.
68 /// See checkBranchCondition() callback for performing custom processing of
69 /// the branching statements.
71 /// check::PreStmt<ReturnStmt>
72 void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const {}
74 /// \brief Post-visit the Statement.
76 /// The method will be called after the analyzer core processes the
77 /// statement. The notification is performed for every explored CFGElement,
78 /// which does not include the control flow statements such as IfStmt. The
79 /// callback can be specialized to be called with any subclass of Stmt.
81 /// check::PostStmt<DeclStmt>
82 void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const;
84 /// \brief Pre-visit the Objective C message.
86 /// This will be called before the analyzer core processes the method call.
87 /// This is called for any action which produces an Objective-C message send,
88 /// including explicit message syntax and property access.
90 /// check::PreObjCMessage
91 void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
93 /// \brief Post-visit the Objective C message.
94 /// \sa checkPreObjCMessage()
96 /// check::PostObjCMessage
97 void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
99 /// \brief Visit an Objective-C message whose receiver is nil.
101 /// This will be called when the analyzer core processes a method call whose
102 /// receiver is definitely nil. In this case, check{Pre/Post}ObjCMessage and
103 /// check{Pre/Post}Call will not be called.
105 /// check::ObjCMessageNil
106 void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const {}
108 /// \brief Pre-visit an abstract "call" event.
110 /// This is used for checkers that want to check arguments or attributed
111 /// behavior for functions and methods no matter how they are being invoked.
113 /// Note that this includes ALL cross-body invocations, so if you want to
114 /// limit your checks to, say, function calls, you should test for that at the
115 /// beginning of your callback function.
118 void checkPreCall(const CallEvent &Call, CheckerContext &C) const {}
120 /// \brief Post-visit an abstract "call" event.
121 /// \sa checkPreObjCMessage()
124 void checkPostCall(const CallEvent &Call, CheckerContext &C) const {}
126 /// \brief Pre-visit of the condition statement of a branch (such as IfStmt).
127 void checkBranchCondition(const Stmt *Condition, CheckerContext &Ctx) const {}
129 /// \brief Called on a load from and a store to a location.
131 /// The method will be called each time a location (pointer) value is
133 /// \param Loc The value of the location (pointer).
134 /// \param IsLoad The flag specifying if the location is a store or a load.
135 /// \param S The load is performed while processing the statement.
138 void checkLocation(SVal Loc, bool IsLoad, const Stmt *S,
139 CheckerContext &) const {}
141 /// \brief Called on binding of a value to a location.
143 /// \param Loc The value of the location (pointer).
144 /// \param Val The value which will be stored at the location Loc.
145 /// \param S The bind is performed while processing the statement S.
148 void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &) const {}
151 /// \brief Called whenever a symbol becomes dead.
153 /// This callback should be used by the checkers to aggressively clean
154 /// up/reduce the checker state, which is important for reducing the overall
155 /// memory usage. Specifically, if a checker keeps symbol specific information
156 /// in the sate, it can and should be dropped after the symbol becomes dead.
157 /// In addition, reporting a bug as soon as the checker becomes dead leads to
158 /// more precise diagnostics. (For example, one should report that a malloced
159 /// variable is not freed right after it goes out of scope.)
161 /// \param SR The SymbolReaper object can be queried to determine which
162 /// symbols are dead.
164 /// check::DeadSymbols
165 void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const {}
167 /// \brief Called when the analyzer core reaches the end of a
168 /// function being analyzed.
170 /// check::EndFunction
171 void checkEndFunction(CheckerContext &Ctx) const {}
173 /// \brief Called after all the paths in the ExplodedGraph reach end of path
174 /// - the symbolic execution graph is fully explored.
176 /// This callback should be used in cases when a checker needs to have a
177 /// global view of the information generated on all paths. For example, to
178 /// compare execution summary/result several paths.
179 /// See IdempotentOperationChecker for a usage example.
181 /// check::EndAnalysis
182 void checkEndAnalysis(ExplodedGraph &G,
184 ExprEngine &Eng) const {}
186 /// \brief Called after analysis of a TranslationUnit is complete.
188 /// check::EndOfTranslationUnit
189 void checkEndOfTranslationUnit(const TranslationUnitDecl *TU,
190 AnalysisManager &Mgr,
191 BugReporter &BR) const {}
194 /// \brief Evaluates function call.
196 /// The analysis core threats all function calls in the same way. However, some
197 /// functions have special meaning, which should be reflected in the program
198 /// state. This callback allows a checker to provide domain specific knowledge
199 /// about the particular functions it knows about.
201 /// \returns true if the call has been successfully evaluated
202 /// and false otherwise. Note, that only one checker can evaluate a call. If
203 /// more than one checker claims that they can evaluate the same call the
207 bool evalCall(const CallExpr *CE, CheckerContext &C) const { return true; }
209 /// \brief Handles assumptions on symbolic values.
211 /// This method is called when a symbolic expression is assumed to be true or
212 /// false. For example, the assumptions are performed when evaluating a
213 /// condition at a branch. The callback allows checkers track the assumptions
214 /// performed on the symbols of interest and change the state accordingly.
217 ProgramStateRef evalAssume(ProgramStateRef State,
219 bool Assumption) const { return State; }
221 /// Allows modifying SymbolReaper object. For example, checkers can explicitly
222 /// register symbols of interest as live. These symbols will not be marked
223 /// dead and removed.
225 /// check::LiveSymbols
226 void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const {}
228 /// \brief Called to determine if the checker currently needs to know if when
229 /// contents of any regions change.
231 /// Since it is not necessarily cheap to compute which regions are being
232 /// changed, this allows the analyzer core to skip the more expensive
233 /// #checkRegionChanges when no checkers are tracking any state.
234 bool wantsRegionChangeUpdate(ProgramStateRef St) const { return true; }
236 /// \brief Called when the contents of one or more regions change.
238 /// This can occur in many different ways: an explicit bind, a blanket
239 /// invalidation of the region contents, or by passing a region to a function
240 /// call whose behavior the analyzer cannot model perfectly.
242 /// \param State The current program state.
243 /// \param Invalidated A set of all symbols potentially touched by the change.
244 /// \param ExplicitRegions The regions explicitly requested for invalidation.
245 /// For a function call, this would be the arguments. For a bind, this
246 /// would be the region being bound to.
247 /// \param Regions The transitive closure of regions accessible from,
248 /// \p ExplicitRegions, i.e. all regions that may have been touched
249 /// by this change. For a simple bind, this list will be the same as
250 /// \p ExplicitRegions, since a bind does not affect the contents of
251 /// anything accessible through the base region.
252 /// \param Call The opaque call triggering this invalidation. Will be 0 if the
253 /// change was not triggered by a call.
255 /// Note that this callback will not be invoked unless
256 /// #wantsRegionChangeUpdate returns \c true.
258 /// check::RegionChanges
260 checkRegionChanges(ProgramStateRef State,
261 const InvalidatedSymbols *Invalidated,
262 ArrayRef<const MemRegion *> ExplicitRegions,
263 ArrayRef<const MemRegion *> Regions,
264 const CallEvent *Call) const {
268 /// \brief Called when pointers escape.
270 /// This notifies the checkers about pointer escape, which occurs whenever
271 /// the analyzer cannot track the symbol any more. For example, as a
272 /// result of assigning a pointer into a global or when it's passed to a
273 /// function call the analyzer cannot model.
275 /// \param State The state at the point of escape.
276 /// \param Escaped The list of escaped symbols.
277 /// \param Call The corresponding CallEvent, if the symbols escape as
278 /// parameters to the given call.
279 /// \param Kind How the symbols have escaped.
280 /// \returns Checkers can modify the state by returning a new state.
281 ProgramStateRef checkPointerEscape(ProgramStateRef State,
282 const InvalidatedSymbols &Escaped,
283 const CallEvent *Call,
284 PointerEscapeKind Kind) const {
288 /// \brief Called when const pointers escape.
290 /// Note: in most cases checkPointerEscape callback is sufficient.
291 /// \sa checkPointerEscape
292 ProgramStateRef checkConstPointerEscape(ProgramStateRef State,
293 const InvalidatedSymbols &Escaped,
294 const CallEvent *Call,
295 PointerEscapeKind Kind) const {
299 /// check::Event<ImplicitNullDerefEvent>
300 void checkEvent(ImplicitNullDerefEvent Event) const {}
302 /// \brief Check every declaration in the AST.
304 /// An AST traversal callback, which should only be used when the checker is
305 /// not path sensitive. It will be called for every Declaration in the AST and
306 /// can be specialized to only be called on subclasses of Decl, for example,
309 /// check::ASTDecl<FunctionDecl>
310 void checkASTDecl(const FunctionDecl *D,
311 AnalysisManager &Mgr,
312 BugReporter &BR) const {}
316 void CheckerDocumentation::checkPostStmt(const DeclStmt *DS,
317 CheckerContext &C) const {
321 } // end namespace ento
322 } // end namespace clang