98 lines
3.3 KiB
C++
98 lines
3.3 KiB
C++
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//== ObjCAtSyncChecker.cpp - nil mutex checker for @synchronized -*- C++ -*--=//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This defines ObjCAtSyncChecker, a builtin check that checks for null pointers
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// used as mutexes for @synchronized.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
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#include "clang/AST/StmtObjC.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
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using namespace clang;
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using namespace ento;
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namespace {
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class ObjCAtSyncChecker
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: public Checker< check::PreStmt<ObjCAtSynchronizedStmt> > {
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mutable std::unique_ptr<BuiltinBug> BT_null;
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mutable std::unique_ptr<BuiltinBug> BT_undef;
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public:
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void checkPreStmt(const ObjCAtSynchronizedStmt *S, CheckerContext &C) const;
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};
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} // end anonymous namespace
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void ObjCAtSyncChecker::checkPreStmt(const ObjCAtSynchronizedStmt *S,
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CheckerContext &C) const {
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const Expr *Ex = S->getSynchExpr();
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ProgramStateRef state = C.getState();
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SVal V = C.getSVal(Ex);
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// Uninitialized value used for the mutex?
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if (V.getAs<UndefinedVal>()) {
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if (ExplodedNode *N = C.generateErrorNode()) {
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if (!BT_undef)
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BT_undef.reset(new BuiltinBug(this, "Uninitialized value used as mutex "
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"for @synchronized"));
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auto report = std::make_unique<PathSensitiveBugReport>(
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*BT_undef, BT_undef->getDescription(), N);
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bugreporter::trackExpressionValue(N, Ex, *report);
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C.emitReport(std::move(report));
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}
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return;
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}
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if (V.isUnknown())
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return;
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// Check for null mutexes.
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ProgramStateRef notNullState, nullState;
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std::tie(notNullState, nullState) = state->assume(V.castAs<DefinedSVal>());
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if (nullState) {
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if (!notNullState) {
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// Generate an error node. This isn't a sink since
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// a null mutex just means no synchronization occurs.
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if (ExplodedNode *N = C.generateNonFatalErrorNode(nullState)) {
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if (!BT_null)
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BT_null.reset(new BuiltinBug(
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this, "Nil value used as mutex for @synchronized() "
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"(no synchronization will occur)"));
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auto report = std::make_unique<PathSensitiveBugReport>(
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*BT_null, BT_null->getDescription(), N);
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bugreporter::trackExpressionValue(N, Ex, *report);
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C.emitReport(std::move(report));
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return;
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}
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}
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// Don't add a transition for 'nullState'. If the value is
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// under-constrained to be null or non-null, assume it is non-null
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// afterwards.
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}
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if (notNullState)
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C.addTransition(notNullState);
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}
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void ento::registerObjCAtSyncChecker(CheckerManager &mgr) {
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mgr.registerChecker<ObjCAtSyncChecker>();
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}
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bool ento::shouldRegisterObjCAtSyncChecker(const CheckerManager &mgr) {
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const LangOptions &LO = mgr.getLangOpts();
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return LO.ObjC;
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}
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