clang 8.0.0

CheckerDocumentation.cpp
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1 //===- CheckerDocumentation.cpp - Documentation checker ---------*- C++ -*-===//
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 checker lists all the checker callbacks and provides documentation for
11 // checker writers.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.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"
21
22 using namespace clang;
23 using namespace ento;
24
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.
28 namespace clang {
29 namespace ento {
30
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
34 /// checking.
35 ///
36 /// \sa CheckerContext
37 class CheckerDocumentation : public Checker< check::PreStmt<ReturnStmt>,
38 check::PostStmt<DeclStmt>,
39 check::PreObjCMessage,
40 check::PostObjCMessage,
41 check::ObjCMessageNil,
42 check::PreCall,
43 check::PostCall,
44 check::BranchCondition,
45 check::NewAllocator,
46 check::Location,
47 check::Bind,
48 check::DeadSymbols,
49 check::BeginFunction,
50 check::EndFunction,
51 check::EndAnalysis,
52 check::EndOfTranslationUnit,
53 eval::Call,
54 eval::Assume,
55 check::LiveSymbols,
56 check::RegionChanges,
57 check::PointerEscape,
58 check::ConstPointerEscape,
59 check::Event<ImplicitNullDerefEvent>,
60 check::ASTDecl<FunctionDecl> > {
61 public:
62 /// Pre-visit the Statement.
63 ///
64 /// The method will be called before the analyzer core processes the
65 /// statement. The notification is performed for every explored CFGElement,
66 /// which does not include the control flow statements such as IfStmt. The
67 /// callback can be specialized to be called with any subclass of Stmt.
68 ///
69 /// See checkBranchCondition() callback for performing custom processing of
70 /// the branching statements.
71 ///
72 /// check::PreStmt<ReturnStmt>
73 void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const {}
74
75 /// Post-visit the Statement.
76 ///
77 /// The method will be called after the analyzer core processes the
78 /// statement. The notification is performed for every explored CFGElement,
79 /// which does not include the control flow statements such as IfStmt. The
80 /// callback can be specialized to be called with any subclass of Stmt.
81 ///
82 /// check::PostStmt<DeclStmt>
83 void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const;
84
85 /// Pre-visit the Objective C message.
86 ///
87 /// This will be called before the analyzer core processes the method call.
88 /// This is called for any action which produces an Objective-C message send,
89 /// including explicit message syntax and property access.
90 ///
91 /// check::PreObjCMessage
92 void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
93
94 /// Post-visit the Objective C message.
95 /// \sa checkPreObjCMessage()
96 ///
97 /// check::PostObjCMessage
98 void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
99
100 /// Visit an Objective-C message whose receiver is nil.
101 ///
102 /// This will be called when the analyzer core processes a method call whose
103 /// receiver is definitely nil. In this case, check{Pre/Post}ObjCMessage and
104 /// check{Pre/Post}Call will not be called.
105 ///
106 /// check::ObjCMessageNil
107 void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const {}
108
109 /// Pre-visit an abstract "call" event.
110 ///
111 /// This is used for checkers that want to check arguments or attributed
112 /// behavior for functions and methods no matter how they are being invoked.
113 ///
114 /// Note that this includes ALL cross-body invocations, so if you want to
115 /// limit your checks to, say, function calls, you should test for that at the
116 /// beginning of your callback function.
117 ///
118 /// check::PreCall
119 void checkPreCall(const CallEvent &Call, CheckerContext &C) const {}
120
121 /// Post-visit an abstract "call" event.
122 /// \sa checkPreObjCMessage()
123 ///
124 /// check::PostCall
125 void checkPostCall(const CallEvent &Call, CheckerContext &C) const {}
126
127 /// Pre-visit of the condition statement of a branch (such as IfStmt).
128 void checkBranchCondition(const Stmt *Condition, CheckerContext &Ctx) const {}
129
130 /// Post-visit the C++ operator new's allocation call.
131 ///
132 /// Execution of C++ operator new consists of the following phases: (1) call
133 /// default or overridden operator new() to allocate memory (2) cast the
134 /// return value of operator new() from void pointer type to class pointer
135 /// type, (3) assuming that the value is non-null, call the object's
136 /// constructor over this pointer, (4) declare that the value of the
137 /// new-expression is this pointer. This callback is called between steps
138 /// (2) and (3). Post-call for the allocator is called after step (1).
139 /// Pre-statement for the new-expression is called on step (4) when the value
140 /// of the expression is evaluated.
141 /// \param NE The C++ new-expression that triggered the allocation.
142 /// \param Target The allocated region, casted to the class type.
143 void checkNewAllocator(const CXXNewExpr *NE, SVal Target,
144 CheckerContext &) const {}
145
146 /// Called on a load from and a store to a location.
147 ///
148 /// The method will be called each time a location (pointer) value is
149 /// accessed.
150 /// \param Loc The value of the location (pointer).
151 /// \param IsLoad The flag specifying if the location is a store or a load.
152 /// \param S The load is performed while processing the statement.
153 ///
154 /// check::Location
155 void checkLocation(SVal Loc, bool IsLoad, const Stmt *S,
156 CheckerContext &) const {}
157
158 /// Called on binding of a value to a location.
159 ///
160 /// \param Loc The value of the location (pointer).
161 /// \param Val The value which will be stored at the location Loc.
162 /// \param S The bind is performed while processing the statement S.
163 ///
164 /// check::Bind
165 void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &) const {}
166
167 /// Called whenever a symbol becomes dead.
168 ///
169 /// This callback should be used by the checkers to aggressively clean
170 /// up/reduce the checker state, which is important for reducing the overall
171 /// memory usage. Specifically, if a checker keeps symbol specific information
172 /// in the state, it can and should be dropped after the symbol becomes dead.
173 /// In addition, reporting a bug as soon as the checker becomes dead leads to
174 /// more precise diagnostics. (For example, one should report that a malloced
175 /// variable is not freed right after it goes out of scope.)
176 ///
177 /// \param SR The SymbolReaper object can be queried to determine which
178 /// symbols are dead.
179 ///
180 /// check::DeadSymbols
181 void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const {}
182
183
184 /// Called when the analyzer core starts analyzing a function,
185 /// regardless of whether it is analyzed at the top level or is inlined.
186 ///
187 /// check::BeginFunction
188 void checkBeginFunction(CheckerContext &Ctx) const {}
189
190 /// Called when the analyzer core reaches the end of a
191 /// function being analyzed regardless of whether it is analyzed at the top
192 /// level or is inlined.
193 ///
194 /// check::EndFunction
195 void checkEndFunction(const ReturnStmt *RS, CheckerContext &Ctx) const {}
196
197 /// Called after all the paths in the ExplodedGraph reach end of path
198 /// - the symbolic execution graph is fully explored.
199 ///
200 /// This callback should be used in cases when a checker needs to have a
201 /// global view of the information generated on all paths. For example, to
202 /// compare execution summary/result several paths.
203 /// See IdempotentOperationChecker for a usage example.
204 ///
205 /// check::EndAnalysis
206 void checkEndAnalysis(ExplodedGraph &G,
207 BugReporter &BR,
208 ExprEngine &Eng) const {}
209
210 /// Called after analysis of a TranslationUnit is complete.
211 ///
212 /// check::EndOfTranslationUnit
213 void checkEndOfTranslationUnit(const TranslationUnitDecl *TU,
214 AnalysisManager &Mgr,
215 BugReporter &BR) const {}
216
217 /// Evaluates function call.
218 ///
219 /// The analysis core threats all function calls in the same way. However, some
220 /// functions have special meaning, which should be reflected in the program
221 /// state. This callback allows a checker to provide domain specific knowledge
222 /// about the particular functions it knows about.
223 ///
224 /// \returns true if the call has been successfully evaluated
225 /// and false otherwise. Note, that only one checker can evaluate a call. If
226 /// more than one checker claims that they can evaluate the same call the
227 /// first one wins.
228 ///
229 /// eval::Call
230 bool evalCall(const CallExpr *CE, CheckerContext &C) const { return true; }
231
232 /// Handles assumptions on symbolic values.
233 ///
234 /// This method is called when a symbolic expression is assumed to be true or
235 /// false. For example, the assumptions are performed when evaluating a
236 /// condition at a branch. The callback allows checkers track the assumptions
237 /// performed on the symbols of interest and change the state accordingly.
238 ///
239 /// eval::Assume
240 ProgramStateRef evalAssume(ProgramStateRef State,
241 SVal Cond,
242 bool Assumption) const { return State; }
243
244 /// Allows modifying SymbolReaper object. For example, checkers can explicitly
245 /// register symbols of interest as live. These symbols will not be marked
246 /// dead and removed.
247 ///
248 /// check::LiveSymbols
249 void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const {}
250
251 /// Called when the contents of one or more regions change.
252 ///
253 /// This can occur in many different ways: an explicit bind, a blanket
254 /// invalidation of the region contents, or by passing a region to a function
255 /// call whose behavior the analyzer cannot model perfectly.
256 ///
257 /// \param State The current program state.
258 /// \param Invalidated A set of all symbols potentially touched by the change.
259 /// \param ExplicitRegions The regions explicitly requested for invalidation.
260 /// For a function call, this would be the arguments. For a bind, this
261 /// would be the region being bound to.
262 /// \param Regions The transitive closure of regions accessible from,
263 /// \p ExplicitRegions, i.e. all regions that may have been touched
264 /// by this change. For a simple bind, this list will be the same as
265 /// \p ExplicitRegions, since a bind does not affect the contents of
266 /// anything accessible through the base region.
267 /// \param LCtx LocationContext that is useful for getting various contextual
268 /// info, like callstack, CFG etc.
269 /// \param Call The opaque call triggering this invalidation. Will be 0 if the
270 /// change was not triggered by a call.
271 ///
272 /// check::RegionChanges
273 ProgramStateRef
274 checkRegionChanges(ProgramStateRef State,
275 const InvalidatedSymbols *Invalidated,
276 ArrayRef<const MemRegion *> ExplicitRegions,
277 ArrayRef<const MemRegion *> Regions,
278 const LocationContext *LCtx,
279 const CallEvent *Call) const {
280 return State;
281 }
282
283 /// Called when pointers escape.
284 ///
285 /// This notifies the checkers about pointer escape, which occurs whenever
286 /// the analyzer cannot track the symbol any more. For example, as a
287 /// result of assigning a pointer into a global or when it's passed to a
288 /// function call the analyzer cannot model.
289 ///
290 /// \param State The state at the point of escape.
291 /// \param Escaped The list of escaped symbols.
292 /// \param Call The corresponding CallEvent, if the symbols escape as
293 /// parameters to the given call.
294 /// \param Kind How the symbols have escaped.
295 /// \returns Checkers can modify the state by returning a new state.
296 ProgramStateRef checkPointerEscape(ProgramStateRef State,
297 const InvalidatedSymbols &Escaped,
298 const CallEvent *Call,
299 PointerEscapeKind Kind) const {
300 return State;
301 }
302
303 /// Called when const pointers escape.
304 ///
305 /// Note: in most cases checkPointerEscape callback is sufficient.
306 /// \sa checkPointerEscape
307 ProgramStateRef checkConstPointerEscape(ProgramStateRef State,
308 const InvalidatedSymbols &Escaped,
309 const CallEvent *Call,
310 PointerEscapeKind Kind) const {
311 return State;
312 }
313
314 /// check::Event<ImplicitNullDerefEvent>
315 void checkEvent(ImplicitNullDerefEvent Event) const {}
316
317 /// Check every declaration in the AST.
318 ///
319 /// An AST traversal callback, which should only be used when the checker is
320 /// not path sensitive. It will be called for every Declaration in the AST and
321 /// can be specialized to only be called on subclasses of Decl, for example,
322 /// FunctionDecl.
323 ///
324 /// check::ASTDecl<FunctionDecl>
325 void checkASTDecl(const FunctionDecl *D,
326 AnalysisManager &Mgr,
327 BugReporter &BR) const {}
328 };
329
330 void CheckerDocumentation::checkPostStmt(const DeclStmt *DS,
331 CheckerContext &C) const {
332 }
333
334 } // end namespace ento
335 } // end namespace clang
ento
clang::FunctionDecl
Represents a function declaration or definition.
Definition: Decl.h:1738
clang::ento::CheckerDocumentation::checkASTDecl
void checkASTDecl(const FunctionDecl *D, AnalysisManager &Mgr, BugReporter &BR) const
Check every declaration in the AST.
Definition: CheckerDocumentation.cpp:325
clang::ento::CheckerDocumentation::checkObjCMessageNil
void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const
Visit an Objective-C message whose receiver is nil.
Definition: CheckerDocumentation.cpp:107
clang::Stmt
Stmt - This represents one statement.
Definition: Stmt.h:66
clang::ento::CheckerDocumentation
This checker documents the callback functions checkers can use to implement the custom handling of th...
Definition: CheckerDocumentation.cpp:37
llvm::DenseSet< SymbolRef >
clang::LocationContext
Definition: AnalysisDeclContext.h:218
BugType.h
clang::ento::CheckerDocumentation::checkEndAnalysis
void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, ExprEngine &Eng) const
Called after all the paths in the ExplodedGraph reach end of path.
Definition: CheckerDocumentation.cpp:206
clang::ento::CheckerDocumentation::checkPreStmt
void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const
Pre-visit the Statement.
Definition: CheckerDocumentation.cpp:73
clang::ento::ExplodedGraph
Definition: ExplodedGraph.h:264
clang::ento::CheckerDocumentation::checkLocation
void checkLocation(SVal Loc, bool IsLoad, const Stmt *S, CheckerContext &) const
Called on a load from and a store to a location.
Definition: CheckerDocumentation.cpp:155
clang::ento::CheckerDocumentation::checkPointerEscape
ProgramStateRef checkPointerEscape(ProgramStateRef State, const InvalidatedSymbols &Escaped, const CallEvent *Call, PointerEscapeKind Kind) const
Called when pointers escape.
Definition: CheckerDocumentation.cpp:296
State
LineState State
Definition: UnwrappedLineFormatter.cpp:877
clang::ento::CheckerDocumentation::checkEndOfTranslationUnit
void checkEndOfTranslationUnit(const TranslationUnitDecl *TU, AnalysisManager &Mgr, BugReporter &BR) const
Called after analysis of a TranslationUnit is complete.
Definition: CheckerDocumentation.cpp:213
Checker.h
CheckerManager.h
clang::ObjCMethodCall
Represents any expression that calls an Objective-C method.
Definition: CallEvent.h:970
clang::ento::CheckerContext
Definition: CheckerContext.h:24
clang::ento::CheckerDocumentation::checkEndFunction
void checkEndFunction(const ReturnStmt *RS, CheckerContext &Ctx) const
Called when the analyzer core reaches the end of a function being analyzed regardless of whether it i...
Definition: CheckerDocumentation.cpp:195
clang::ento::CheckerDocumentation::checkBind
void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &) const
Called on binding of a value to a location.
Definition: CheckerDocumentation.cpp:165
clang::ento::CheckerDocumentation::checkBranchCondition
void checkBranchCondition(const Stmt *Condition, CheckerContext &Ctx) const
Pre-visit of the condition statement of a branch (such as IfStmt).
Definition: CheckerDocumentation.cpp:128
llvm::ArrayRef
Definition: LLVM.h:32
clang::ento::ImplicitNullDerefEvent
We dereferenced a location that may be null.
Definition: Checker.h:552
clang::ento::AnalysisManager
Definition: AnalysisManager.h:31
clang::ento::Checker
Definition: Checker.h:516
clang::ento::CheckerDocumentation::checkBeginFunction
void checkBeginFunction(CheckerContext &Ctx) const
Called when the analyzer core starts analyzing a function, regardless of whether it is analyzed at th...
Definition: CheckerDocumentation.cpp:188
clang::ento::CheckerDocumentation::checkDeadSymbols
void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const
Called whenever a symbol becomes dead.
Definition: CheckerDocumentation.cpp:181
clang::ento::CheckerDocumentation::evalCall
bool evalCall(const CallExpr *CE, CheckerContext &C) const
Evaluates function call.
Definition: CheckerDocumentation.cpp:230
clang::ReturnStmt
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:2443
BuiltinCheckerRegistration.h
clang::ento::BugReporter
BugReporter is a utility class for generating PathDiagnostics for analysis.
Definition: BugReporter.h:412
Kind
Kind
Definition: ChrootChecker.cpp:29
clang::ento::Loc
Definition: SVals.h:318
llvm::IntrusiveRefCntPtr
Definition: LLVM.h:45
clang::CXXNewExpr
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1914
clang::DeclStmt
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1143
clang::ento::CheckerDocumentation::checkLiveSymbols
void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const
Allows modifying SymbolReaper object.
Definition: CheckerDocumentation.cpp:249
clang::ento::SVal
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:76
clang::ento::CheckerDocumentation::checkPreCall
void checkPreCall(const CallEvent &Call, CheckerContext &C) const
Pre-visit an abstract "call" event.
Definition: CheckerDocumentation.cpp:119
clang::ento::SymbolReaper
A class responsible for cleaning up unused symbols.
Definition: SymbolManager.h:549
clang::ento::CheckerDocumentation::checkConstPointerEscape
ProgramStateRef checkConstPointerEscape(ProgramStateRef State, const InvalidatedSymbols &Escaped, const CallEvent *Call, PointerEscapeKind Kind) const
Called when const pointers escape.
Definition: CheckerDocumentation.cpp:307
clang::ento::CheckerDocumentation::checkPreObjCMessage
void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const
Pre-visit the Objective C message.
Definition: CheckerDocumentation.cpp:92
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:22
clang::ento::CheckerDocumentation::checkPostCall
void checkPostCall(const CallEvent &Call, CheckerContext &C) const
Post-visit an abstract "call" event.
Definition: CheckerDocumentation.cpp:125
clang::ento::CheckerDocumentation::checkPostStmt
void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const
Post-visit the Statement.
Definition: CheckerDocumentation.cpp:330
clang::ento::CheckerDocumentation::evalAssume
ProgramStateRef evalAssume(ProgramStateRef State, SVal Cond, bool Assumption) const
Handles assumptions on symbolic values.
Definition: CheckerDocumentation.cpp:240
clang::ento::CallEvent
Represents an abstract call to a function or method along a particular path.
Definition: CallEvent.h:171
clang::ento::PointerEscapeKind
PointerEscapeKind
Describes the different reasons a pointer escapes during analysis.
Definition: CheckerManager.h:76
clang::ento::CheckerDocumentation::checkPostObjCMessage
void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const
Post-visit the Objective C message.
Definition: CheckerDocumentation.cpp:98
clang::CallExpr
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2396
clang::ento::CheckerDocumentation::checkRegionChanges
ProgramStateRef checkRegionChanges(ProgramStateRef State, const InvalidatedSymbols *Invalidated, ArrayRef< const MemRegion *> ExplicitRegions, ArrayRef< const MemRegion *> Regions, const LocationContext *LCtx, const CallEvent *Call) const
Called when the contents of one or more regions change.
Definition: CheckerDocumentation.cpp:274
clang::TranslationUnitDecl
The top declaration context.
Definition: Decl.h:108
clang::ento::CheckerDocumentation::checkEvent
void checkEvent(ImplicitNullDerefEvent Event) const
check::Event<ImplicitNullDerefEvent>
Definition: CheckerDocumentation.cpp:315
clang::ento::CheckerDocumentation::checkNewAllocator
void checkNewAllocator(const CXXNewExpr *NE, SVal Target, CheckerContext &) const
Post-visit the C++ operator new&#39;s allocation call.
Definition: CheckerDocumentation.cpp:143
clang::ento::ExprEngine
Definition: ExprEngine.h:84
ProgramStateTrait.h
CheckerContext.h