| //===- CheckerDocumentation.cpp - Documentation checker ---------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This checker lists all the checker callbacks and provides documentation for |
| // checker writers. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" |
| #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" |
| #include "clang/StaticAnalyzer/Core/Checker.h" |
| #include "clang/StaticAnalyzer/Core/CheckerManager.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" |
| |
| using namespace clang; |
| using namespace ento; |
| |
| // All checkers should be placed into anonymous namespace. |
| // We place the CheckerDocumentation inside ento namespace to make the |
| // it visible in doxygen. |
| namespace clang { |
| namespace ento { |
| |
| /// This checker documents the callback functions checkers can use to implement |
| /// the custom handling of the specific events during path exploration as well |
| /// as reporting bugs. Most of the callbacks are targeted at path-sensitive |
| /// checking. |
| /// |
| /// \sa CheckerContext |
| class CheckerDocumentation : public Checker< check::PreStmt<ReturnStmt>, |
| check::PostStmt<DeclStmt>, |
| check::PreObjCMessage, |
| check::PostObjCMessage, |
| check::ObjCMessageNil, |
| check::PreCall, |
| check::PostCall, |
| check::BranchCondition, |
| check::NewAllocator, |
| check::Location, |
| check::Bind, |
| check::DeadSymbols, |
| check::BeginFunction, |
| check::EndFunction, |
| check::EndAnalysis, |
| check::EndOfTranslationUnit, |
| eval::Call, |
| eval::Assume, |
| check::LiveSymbols, |
| check::RegionChanges, |
| check::PointerEscape, |
| check::ConstPointerEscape, |
| check::Event<ImplicitNullDerefEvent>, |
| check::ASTDecl<FunctionDecl> > { |
| public: |
| /// Pre-visit the Statement. |
| /// |
| /// The method will be called before the analyzer core processes the |
| /// statement. The notification is performed for every explored CFGElement, |
| /// which does not include the control flow statements such as IfStmt. The |
| /// callback can be specialized to be called with any subclass of Stmt. |
| /// |
| /// See checkBranchCondition() callback for performing custom processing of |
| /// the branching statements. |
| /// |
| /// check::PreStmt<ReturnStmt> |
| void checkPreStmt(const ReturnStmt *DS, CheckerContext &C) const {} |
| |
| /// Post-visit the Statement. |
| /// |
| /// The method will be called after the analyzer core processes the |
| /// statement. The notification is performed for every explored CFGElement, |
| /// which does not include the control flow statements such as IfStmt. The |
| /// callback can be specialized to be called with any subclass of Stmt. |
| /// |
| /// check::PostStmt<DeclStmt> |
| void checkPostStmt(const DeclStmt *DS, CheckerContext &C) const; |
| |
| /// Pre-visit the Objective C message. |
| /// |
| /// This will be called before the analyzer core processes the method call. |
| /// This is called for any action which produces an Objective-C message send, |
| /// including explicit message syntax and property access. |
| /// |
| /// check::PreObjCMessage |
| void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {} |
| |
| /// Post-visit the Objective C message. |
| /// \sa checkPreObjCMessage() |
| /// |
| /// check::PostObjCMessage |
| void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const {} |
| |
| /// Visit an Objective-C message whose receiver is nil. |
| /// |
| /// This will be called when the analyzer core processes a method call whose |
| /// receiver is definitely nil. In this case, check{Pre/Post}ObjCMessage and |
| /// check{Pre/Post}Call will not be called. |
| /// |
| /// check::ObjCMessageNil |
| void checkObjCMessageNil(const ObjCMethodCall &M, CheckerContext &C) const {} |
| |
| /// Pre-visit an abstract "call" event. |
| /// |
| /// This is used for checkers that want to check arguments or attributed |
| /// behavior for functions and methods no matter how they are being invoked. |
| /// |
| /// Note that this includes ALL cross-body invocations, so if you want to |
| /// limit your checks to, say, function calls, you should test for that at the |
| /// beginning of your callback function. |
| /// |
| /// check::PreCall |
| void checkPreCall(const CallEvent &Call, CheckerContext &C) const {} |
| |
| /// Post-visit an abstract "call" event. |
| /// \sa checkPreObjCMessage() |
| /// |
| /// check::PostCall |
| void checkPostCall(const CallEvent &Call, CheckerContext &C) const {} |
| |
| /// Pre-visit of the condition statement of a branch (such as IfStmt). |
| void checkBranchCondition(const Stmt *Condition, CheckerContext &Ctx) const {} |
| |
| /// Post-visit the C++ operator new's allocation call. |
| /// |
| /// Execution of C++ operator new consists of the following phases: (1) call |
| /// default or overridden operator new() to allocate memory (2) cast the |
| /// return value of operator new() from void pointer type to class pointer |
| /// type, (3) assuming that the value is non-null, call the object's |
| /// constructor over this pointer, (4) declare that the value of the |
| /// new-expression is this pointer. This callback is called between steps |
| /// (2) and (3). Post-call for the allocator is called after step (1). |
| /// Pre-statement for the new-expression is called on step (4) when the value |
| /// of the expression is evaluated. |
| /// \param NE The C++ new-expression that triggered the allocation. |
| /// \param Target The allocated region, casted to the class type. |
| void checkNewAllocator(const CXXNewExpr *NE, SVal Target, |
| CheckerContext &) const {} |
| |
| /// Called on a load from and a store to a location. |
| /// |
| /// The method will be called each time a location (pointer) value is |
| /// accessed. |
| /// \param Loc The value of the location (pointer). |
| /// \param IsLoad The flag specifying if the location is a store or a load. |
| /// \param S The load is performed while processing the statement. |
| /// |
| /// check::Location |
| void checkLocation(SVal Loc, bool IsLoad, const Stmt *S, |
| CheckerContext &) const {} |
| |
| /// Called on binding of a value to a location. |
| /// |
| /// \param Loc The value of the location (pointer). |
| /// \param Val The value which will be stored at the location Loc. |
| /// \param S The bind is performed while processing the statement S. |
| /// |
| /// check::Bind |
| void checkBind(SVal Loc, SVal Val, const Stmt *S, CheckerContext &) const {} |
| |
| /// Called whenever a symbol becomes dead. |
| /// |
| /// This callback should be used by the checkers to aggressively clean |
| /// up/reduce the checker state, which is important for reducing the overall |
| /// memory usage. Specifically, if a checker keeps symbol specific information |
| /// in the state, it can and should be dropped after the symbol becomes dead. |
| /// In addition, reporting a bug as soon as the checker becomes dead leads to |
| /// more precise diagnostics. (For example, one should report that a malloced |
| /// variable is not freed right after it goes out of scope.) |
| /// |
| /// \param SR The SymbolReaper object can be queried to determine which |
| /// symbols are dead. |
| /// |
| /// check::DeadSymbols |
| void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const {} |
| |
| |
| /// Called when the analyzer core starts analyzing a function, |
| /// regardless of whether it is analyzed at the top level or is inlined. |
| /// |
| /// check::BeginFunction |
| void checkBeginFunction(CheckerContext &Ctx) const {} |
| |
| /// Called when the analyzer core reaches the end of a |
| /// function being analyzed regardless of whether it is analyzed at the top |
| /// level or is inlined. |
| /// |
| /// check::EndFunction |
| void checkEndFunction(const ReturnStmt *RS, CheckerContext &Ctx) const {} |
| |
| /// Called after all the paths in the ExplodedGraph reach end of path |
| /// - the symbolic execution graph is fully explored. |
| /// |
| /// This callback should be used in cases when a checker needs to have a |
| /// global view of the information generated on all paths. For example, to |
| /// compare execution summary/result several paths. |
| /// See IdempotentOperationChecker for a usage example. |
| /// |
| /// check::EndAnalysis |
| void checkEndAnalysis(ExplodedGraph &G, |
| BugReporter &BR, |
| ExprEngine &Eng) const {} |
| |
| /// Called after analysis of a TranslationUnit is complete. |
| /// |
| /// check::EndOfTranslationUnit |
| void checkEndOfTranslationUnit(const TranslationUnitDecl *TU, |
| AnalysisManager &Mgr, |
| BugReporter &BR) const {} |
| |
| /// Evaluates function call. |
| /// |
| /// The analysis core treats all function calls in the same way. However, some |
| /// functions have special meaning, which should be reflected in the program |
| /// state. This callback allows a checker to provide domain specific knowledge |
| /// about the particular functions it knows about. |
| /// |
| /// \returns true if the call has been successfully evaluated |
| /// and false otherwise. Note, that only one checker can evaluate a call. If |
| /// more than one checker claims that they can evaluate the same call the |
| /// first one wins. |
| /// |
| /// eval::Call |
| bool evalCall(const CallExpr *CE, CheckerContext &C) const { return true; } |
| |
| /// Handles assumptions on symbolic values. |
| /// |
| /// This method is called when a symbolic expression is assumed to be true or |
| /// false. For example, the assumptions are performed when evaluating a |
| /// condition at a branch. The callback allows checkers track the assumptions |
| /// performed on the symbols of interest and change the state accordingly. |
| /// |
| /// eval::Assume |
| ProgramStateRef evalAssume(ProgramStateRef State, |
| SVal Cond, |
| bool Assumption) const { return State; } |
| |
| /// Allows modifying SymbolReaper object. For example, checkers can explicitly |
| /// register symbols of interest as live. These symbols will not be marked |
| /// dead and removed. |
| /// |
| /// check::LiveSymbols |
| void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const {} |
| |
| /// Called when the contents of one or more regions change. |
| /// |
| /// This can occur in many different ways: an explicit bind, a blanket |
| /// invalidation of the region contents, or by passing a region to a function |
| /// call whose behavior the analyzer cannot model perfectly. |
| /// |
| /// \param State The current program state. |
| /// \param Invalidated A set of all symbols potentially touched by the change. |
| /// \param ExplicitRegions The regions explicitly requested for invalidation. |
| /// For a function call, this would be the arguments. For a bind, this |
| /// would be the region being bound to. |
| /// \param Regions The transitive closure of regions accessible from, |
| /// \p ExplicitRegions, i.e. all regions that may have been touched |
| /// by this change. For a simple bind, this list will be the same as |
| /// \p ExplicitRegions, since a bind does not affect the contents of |
| /// anything accessible through the base region. |
| /// \param LCtx LocationContext that is useful for getting various contextual |
| /// info, like callstack, CFG etc. |
| /// \param Call The opaque call triggering this invalidation. Will be 0 if the |
| /// change was not triggered by a call. |
| /// |
| /// check::RegionChanges |
| ProgramStateRef |
| checkRegionChanges(ProgramStateRef State, |
| const InvalidatedSymbols *Invalidated, |
| ArrayRef<const MemRegion *> ExplicitRegions, |
| ArrayRef<const MemRegion *> Regions, |
| const LocationContext *LCtx, |
| const CallEvent *Call) const { |
| return State; |
| } |
| |
| /// Called when pointers escape. |
| /// |
| /// This notifies the checkers about pointer escape, which occurs whenever |
| /// the analyzer cannot track the symbol any more. For example, as a |
| /// result of assigning a pointer into a global or when it's passed to a |
| /// function call the analyzer cannot model. |
| /// |
| /// \param State The state at the point of escape. |
| /// \param Escaped The list of escaped symbols. |
| /// \param Call The corresponding CallEvent, if the symbols escape as |
| /// parameters to the given call. |
| /// \param Kind How the symbols have escaped. |
| /// \returns Checkers can modify the state by returning a new state. |
| ProgramStateRef checkPointerEscape(ProgramStateRef State, |
| const InvalidatedSymbols &Escaped, |
| const CallEvent *Call, |
| PointerEscapeKind Kind) const { |
| return State; |
| } |
| |
| /// Called when const pointers escape. |
| /// |
| /// Note: in most cases checkPointerEscape callback is sufficient. |
| /// \sa checkPointerEscape |
| ProgramStateRef checkConstPointerEscape(ProgramStateRef State, |
| const InvalidatedSymbols &Escaped, |
| const CallEvent *Call, |
| PointerEscapeKind Kind) const { |
| return State; |
| } |
| |
| /// check::Event<ImplicitNullDerefEvent> |
| void checkEvent(ImplicitNullDerefEvent Event) const {} |
| |
| /// Check every declaration in the AST. |
| /// |
| /// An AST traversal callback, which should only be used when the checker is |
| /// not path sensitive. It will be called for every Declaration in the AST and |
| /// can be specialized to only be called on subclasses of Decl, for example, |
| /// FunctionDecl. |
| /// |
| /// check::ASTDecl<FunctionDecl> |
| void checkASTDecl(const FunctionDecl *D, |
| AnalysisManager &Mgr, |
| BugReporter &BR) const {} |
| }; |
| |
| void CheckerDocumentation::checkPostStmt(const DeclStmt *DS, |
| CheckerContext &C) const { |
| } |
| |
| } // end namespace ento |
| } // end namespace clang |