clang 10.0.0git

CheckerDocumentation.cpp
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1 //===- CheckerDocumentation.cpp - Documentation checker ---------*- C++ -*-===//
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 checker lists all the checker callbacks and provides documentation for
10 // checker writers.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
15 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
16 #include "clang/StaticAnalyzer/Core/Checker.h"
17 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
20
21 using namespace clang;
22 using namespace ento;
23
24 // All checkers should be placed into anonymous namespace.
25 // We place the CheckerDocumentation inside ento namespace to make the
26 // it visible in doxygen.
27 namespace clang {
28 namespace ento {
29
30 /// This checker documents the callback functions checkers can use to implement
31 /// the custom handling of the specific events during path exploration as well
32 /// as reporting bugs. Most of the callbacks are targeted at path-sensitive
33 /// checking.
34 ///
35 /// \sa CheckerContext
36 class CheckerDocumentation : public Checker< check::PreStmt<ReturnStmt>,
37 check::PostStmt<DeclStmt>,
38 check::PreObjCMessage,
39 check::PostObjCMessage,
40 check::ObjCMessageNil,
41 check::PreCall,
42 check::PostCall,
43 check::BranchCondition,
44 check::NewAllocator,
45 check::Location,
46 check::Bind,
47 check::DeadSymbols,
48 check::BeginFunction,
49 check::EndFunction,
50 check::EndAnalysis,
51 check::EndOfTranslationUnit,
52 eval::Call,
53 eval::Assume,
54 check::LiveSymbols,
55 check::RegionChanges,
56 check::PointerEscape,
57 check::ConstPointerEscape,
58 check::Event<ImplicitNullDerefEvent>,
59 check::ASTDecl<FunctionDecl> > {
60 public:
61 /// Pre-visit the Statement.
62 ///
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.
67 ///
68 /// See checkBranchCondition() callback for performing custom processing of
69 /// the branching statements.
70 ///
71 /// check::PreStmt<ReturnStmt>
72 void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const {}
73
74 /// Post-visit the Statement.
75 ///
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.
80 ///
81 /// check::PostStmt<DeclStmt>
82 void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const;
83
84 /// Pre-visit the Objective C message.
85 ///
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.
89 ///
90 /// check::PreObjCMessage
91 void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
92
93 /// Post-visit the Objective C message.
94 /// \sa checkPreObjCMessage()
95 ///
96 /// check::PostObjCMessage
97 void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {}
98
99 /// Visit an Objective-C message whose receiver is nil.
100 ///
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.
104 ///
105 /// check::ObjCMessageNil
106 void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const {}
107
108 /// Pre-visit an abstract "call" event.
109 ///
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.
112 ///
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.
116 ///
117 /// check::PreCall
118 void checkPreCall(const CallEvent &Call, CheckerContext &C) const {}
119
120 /// Post-visit an abstract "call" event.
121 /// \sa checkPreObjCMessage()
122 ///
123 /// check::PostCall
124 void checkPostCall(const CallEvent &Call, CheckerContext &C) const {}
125
126 /// Pre-visit of the condition statement of a branch (such as IfStmt).
127 void checkBranchCondition(const Stmt *Condition, CheckerContext &Ctx) const {}
128
129 /// Post-visit the C++ operator new's allocation call.
130 ///
131 /// Execution of C++ operator new consists of the following phases: (1) call
132 /// default or overridden operator new() to allocate memory (2) cast the
133 /// return value of operator new() from void pointer type to class pointer
134 /// type, (3) assuming that the value is non-null, call the object's
135 /// constructor over this pointer, (4) declare that the value of the
136 /// new-expression is this pointer. This callback is called between steps
137 /// (2) and (3). Post-call for the allocator is called after step (1).
138 /// Pre-statement for the new-expression is called on step (4) when the value
139 /// of the expression is evaluated.
140 /// \param NE The C++ new-expression that triggered the allocation.
141 /// \param Target The allocated region, casted to the class type.
142 void checkNewAllocator(const CXXNewExpr *NE, SVal Target,
143 CheckerContext &) const {}
144
145 /// Called on a load from and a store to a location.
146 ///
147 /// The method will be called each time a location (pointer) value is
148 /// accessed.
149 /// \param Loc The value of the location (pointer).
150 /// \param IsLoad The flag specifying if the location is a store or a load.
151 /// \param S The load is performed while processing the statement.
152 ///
153 /// check::Location
154 void checkLocation(SVal Loc, bool IsLoad, const Stmt *S,
155 CheckerContext &) const {}
156
157 /// Called on binding of a value to a location.
158 ///
159 /// \param Loc The value of the location (pointer).
160 /// \param Val The value which will be stored at the location Loc.
161 /// \param S The bind is performed while processing the statement S.
162 ///
163 /// check::Bind
164 void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &) const {}
165
166 /// Called whenever a symbol becomes dead.
167 ///
168 /// This callback should be used by the checkers to aggressively clean
169 /// up/reduce the checker state, which is important for reducing the overall
170 /// memory usage. Specifically, if a checker keeps symbol specific information
171 /// in the state, it can and should be dropped after the symbol becomes dead.
172 /// In addition, reporting a bug as soon as the checker becomes dead leads to
173 /// more precise diagnostics. (For example, one should report that a malloced
174 /// variable is not freed right after it goes out of scope.)
175 ///
176 /// \param SR The SymbolReaper object can be queried to determine which
177 /// symbols are dead.
178 ///
179 /// check::DeadSymbols
180 void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const {}
181
182
183 /// Called when the analyzer core starts analyzing a function,
184 /// regardless of whether it is analyzed at the top level or is inlined.
185 ///
186 /// check::BeginFunction
187 void checkBeginFunction(CheckerContext &Ctx) const {}
188
189 /// Called when the analyzer core reaches the end of a
190 /// function being analyzed regardless of whether it is analyzed at the top
191 /// level or is inlined.
192 ///
193 /// check::EndFunction
194 void checkEndFunction(const ReturnStmt *RS, CheckerContext &Ctx) const {}
195
196 /// Called after all the paths in the ExplodedGraph reach end of path
197 /// - the symbolic execution graph is fully explored.
198 ///
199 /// This callback should be used in cases when a checker needs to have a
200 /// global view of the information generated on all paths. For example, to
201 /// compare execution summary/result several paths.
202 /// See IdempotentOperationChecker for a usage example.
203 ///
204 /// check::EndAnalysis
205 void checkEndAnalysis(ExplodedGraph &G,
206 BugReporter &BR,
207 ExprEngine &Eng) const {}
208
209 /// Called after analysis of a TranslationUnit is complete.
210 ///
211 /// check::EndOfTranslationUnit
212 void checkEndOfTranslationUnit(const TranslationUnitDecl *TU,
213 AnalysisManager &Mgr,
214 BugReporter &BR) const {}
215
216 /// Evaluates function call.
217 ///
218 /// The analysis core treats all function calls in the same way. However, some
219 /// functions have special meaning, which should be reflected in the program
220 /// state. This callback allows a checker to provide domain specific knowledge
221 /// about the particular functions it knows about.
222 ///
223 /// \returns true if the call has been successfully evaluated
224 /// and false otherwise. Note, that only one checker can evaluate a call. If
225 /// more than one checker claims that they can evaluate the same call the
226 /// first one wins.
227 ///
228 /// eval::Call
229 bool evalCall(const CallExpr *CE, CheckerContext &C) const { return true; }
230
231 /// Handles assumptions on symbolic values.
232 ///
233 /// This method is called when a symbolic expression is assumed to be true or
234 /// false. For example, the assumptions are performed when evaluating a
235 /// condition at a branch. The callback allows checkers track the assumptions
236 /// performed on the symbols of interest and change the state accordingly.
237 ///
238 /// eval::Assume
239 ProgramStateRef evalAssume(ProgramStateRef State,
240 SVal Cond,
241 bool Assumption) const { return State; }
242
243 /// Allows modifying SymbolReaper object. For example, checkers can explicitly
244 /// register symbols of interest as live. These symbols will not be marked
245 /// dead and removed.
246 ///
247 /// check::LiveSymbols
248 void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const {}
249
250 /// Called when the contents of one or more regions change.
251 ///
252 /// This can occur in many different ways: an explicit bind, a blanket
253 /// invalidation of the region contents, or by passing a region to a function
254 /// call whose behavior the analyzer cannot model perfectly.
255 ///
256 /// \param State The current program state.
257 /// \param Invalidated A set of all symbols potentially touched by the change.
258 /// \param ExplicitRegions The regions explicitly requested for invalidation.
259 /// For a function call, this would be the arguments. For a bind, this
260 /// would be the region being bound to.
261 /// \param Regions The transitive closure of regions accessible from,
262 /// \p ExplicitRegions, i.e. all regions that may have been touched
263 /// by this change. For a simple bind, this list will be the same as
264 /// \p ExplicitRegions, since a bind does not affect the contents of
265 /// anything accessible through the base region.
266 /// \param LCtx LocationContext that is useful for getting various contextual
267 /// info, like callstack, CFG etc.
268 /// \param Call The opaque call triggering this invalidation. Will be 0 if the
269 /// change was not triggered by a call.
270 ///
271 /// check::RegionChanges
272 ProgramStateRef
273 checkRegionChanges(ProgramStateRef State,
274 const InvalidatedSymbols *Invalidated,
275 ArrayRef<const MemRegion *> ExplicitRegions,
276 ArrayRef<const MemRegion *> Regions,
277 const LocationContext *LCtx,
278 const CallEvent *Call) const {
279 return State;
280 }
281
282 /// Called when pointers escape.
283 ///
284 /// This notifies the checkers about pointer escape, which occurs whenever
285 /// the analyzer cannot track the symbol any more. For example, as a
286 /// result of assigning a pointer into a global or when it's passed to a
287 /// function call the analyzer cannot model.
288 ///
289 /// \param State The state at the point of escape.
290 /// \param Escaped The list of escaped symbols.
291 /// \param Call The corresponding CallEvent, if the symbols escape as
292 /// parameters to the given call.
293 /// \param Kind How the symbols have escaped.
294 /// \returns Checkers can modify the state by returning a new state.
295 ProgramStateRef checkPointerEscape(ProgramStateRef State,
296 const InvalidatedSymbols &Escaped,
297 const CallEvent *Call,
298 PointerEscapeKind Kind) const {
299 return State;
300 }
301
302 /// Called when const pointers escape.
303 ///
304 /// Note: in most cases checkPointerEscape callback is sufficient.
305 /// \sa checkPointerEscape
306 ProgramStateRef checkConstPointerEscape(ProgramStateRef State,
307 const InvalidatedSymbols &Escaped,
308 const CallEvent *Call,
309 PointerEscapeKind Kind) const {
310 return State;
311 }
312
313 /// check::Event<ImplicitNullDerefEvent>
314 void checkEvent(ImplicitNullDerefEvent Event) const {}
315
316 /// Check every declaration in the AST.
317 ///
318 /// An AST traversal callback, which should only be used when the checker is
319 /// not path sensitive. It will be called for every Declaration in the AST and
320 /// can be specialized to only be called on subclasses of Decl, for example,
321 /// FunctionDecl.
322 ///
323 /// check::ASTDecl<FunctionDecl>
324 void checkASTDecl(const FunctionDecl *D,
325 AnalysisManager &Mgr,
326 BugReporter &BR) const {}
327 };
328
329 void CheckerDocumentation::checkPostStmt(const DeclStmt *DS,
330 CheckerContext &C) const {
331 }
332
333 } // end namespace ento
334 } // end namespace clang
ento
clang::FunctionDecl
Represents a function declaration or definition.
Definition: Decl.h:1783
clang::ento::CheckerDocumentation::checkASTDecl
void checkASTDecl(const FunctionDecl *D, AnalysisManager &Mgr, BugReporter &BR) const
Check every declaration in the AST.
Definition: CheckerDocumentation.cpp:324
clang::ento::CheckerDocumentation::checkObjCMessageNil
void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const
Visit an Objective-C message whose receiver is nil.
Definition: CheckerDocumentation.cpp:106
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:36
llvm::DenseSet< SymbolRef >
clang::LocationContext
Definition: AnalysisDeclContext.h:216
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:205
clang::ento::CheckerDocumentation::checkPreStmt
void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const
Pre-visit the Statement.
Definition: CheckerDocumentation.cpp:72
clang::ento::ExplodedGraph
Definition: ExplodedGraph.h:304
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:154
clang::ento::CheckerDocumentation::checkPointerEscape
ProgramStateRef checkPointerEscape(ProgramStateRef State, const InvalidatedSymbols &Escaped, const CallEvent *Call, PointerEscapeKind Kind) const
Called when pointers escape.
Definition: CheckerDocumentation.cpp:295
State
LineState State
Definition: UnwrappedLineFormatter.cpp:932
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:212
Checker.h
CheckerManager.h
clang::ObjCMethodCall
Represents any expression that calls an Objective-C method.
Definition: CallEvent.h:938
clang::ento::CheckerContext
Definition: CheckerContext.h:23
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:194
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:164
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:127
llvm::ArrayRef
Definition: LLVM.h:31
clang::ento::ImplicitNullDerefEvent
We dereferenced a location that may be null.
Definition: Checker.h:553
clang::ento::AnalysisManager
Definition: AnalysisManager.h:30
clang::ento::Checker
Definition: Checker.h:517
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:187
clang::ento::CheckerDocumentation::checkDeadSymbols
void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const
Called whenever a symbol becomes dead.
Definition: CheckerDocumentation.cpp:180
clang::ento::CheckerDocumentation::evalCall
bool evalCall(const CallExpr *CE, CheckerContext &C) const
Evaluates function call.
Definition: CheckerDocumentation.cpp:229
clang::ReturnStmt
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:2636
BuiltinCheckerRegistration.h
clang::ento::BugReporter
BugReporter is a utility class for generating PathDiagnostics for analysis.
Definition: BugReporter.h:576
Kind
Kind
Definition: ChrootChecker.cpp:29
clang::ento::Loc
Definition: SVals.h:320
llvm::IntrusiveRefCntPtr< const ProgramState >
clang::CXXNewExpr
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:2100
clang::DeclStmt
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1225
clang::ento::CheckerDocumentation::checkLiveSymbols
void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const
Allows modifying SymbolReaper object.
Definition: CheckerDocumentation.cpp:248
clang::ento::SVal
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:75
clang::ento::CheckerDocumentation::checkPreCall
void checkPreCall(const CallEvent &Call, CheckerContext &C) const
Pre-visit an abstract "call" event.
Definition: CheckerDocumentation.cpp:118
clang::ento::SymbolReaper
A class responsible for cleaning up unused symbols.
Definition: SymbolManager.h:548
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:306
clang::ento::CheckerDocumentation::checkPreObjCMessage
void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const
Pre-visit the Objective C message.
Definition: CheckerDocumentation.cpp:91
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:21
clang::ento::CheckerDocumentation::checkPostCall
void checkPostCall(const CallEvent &Call, CheckerContext &C) const
Post-visit an abstract "call" event.
Definition: CheckerDocumentation.cpp:124
clang::ento::CheckerDocumentation::checkPostStmt
void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const
Post-visit the Statement.
Definition: CheckerDocumentation.cpp:329
clang::interp::NE
bool NE(InterpState &S, CodePtr OpPC)
Definition: Interp.h:223
clang::ento::CheckerDocumentation::evalAssume
ProgramStateRef evalAssume(ProgramStateRef State, SVal Cond, bool Assumption) const
Handles assumptions on symbolic values.
Definition: CheckerDocumentation.cpp:239
clang::ento::CallEvent
Represents an abstract call to a function or method along a particular path.
Definition: CallEvent.h:138
clang::ento::PointerEscapeKind
PointerEscapeKind
Describes the different reasons a pointer escapes during analysis.
Definition: CheckerManager.h:75
clang::ento::CheckerDocumentation::checkPostObjCMessage
void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const
Post-visit the Objective C message.
Definition: CheckerDocumentation.cpp:97
clang::CallExpr
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2546
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:273
clang::TranslationUnitDecl
The top declaration context.
Definition: Decl.h:82
clang::ento::CheckerDocumentation::checkEvent
void checkEvent(ImplicitNullDerefEvent Event) const
check::Event<ImplicitNullDerefEvent>
Definition: CheckerDocumentation.cpp:314
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:142
clang::ento::ExprEngine
Definition: ExprEngine.h:84
ProgramStateTrait.h
CheckerContext.h