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//===- CheckerDocumentation.cpp - Documentation checker ---------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This checker lists all the checker callbacks and provides documentation for
// checker writers.
#include "ClangSACheckers.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::ASTDecl<FunctionDecl> > {
/// 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 sate, 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 threats 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
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