forked from OSchip/llvm-project
95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
//== ObjCAtSyncChecker.cpp - nil mutex checker for @synchronized -*- C++ -*--=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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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 "GRExprEngineInternalChecks.h"
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#include "clang/Checker/BugReporter/BugType.h"
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#include "clang/Checker/Checkers/DereferenceChecker.h"
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#include "clang/Checker/PathSensitive/CheckerVisitor.h"
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#include "clang/Checker/PathSensitive/GRExprEngine.h"
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using namespace clang;
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namespace {
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class ObjCAtSyncChecker : public CheckerVisitor<ObjCAtSyncChecker> {
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BuiltinBug *BT_null;
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BuiltinBug *BT_undef;
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public:
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ObjCAtSyncChecker() : BT_null(0), BT_undef(0) {}
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static void *getTag() { static int tag = 0; return &tag; }
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void PreVisitObjCAtSynchronizedStmt(CheckerContext &C,
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const ObjCAtSynchronizedStmt *S);
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};
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} // end anonymous namespace
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void clang::RegisterObjCAtSyncChecker(GRExprEngine &Eng) {
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// @synchronized is an Objective-C 2 feature.
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if (Eng.getContext().getLangOptions().ObjC2)
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Eng.registerCheck(new ObjCAtSyncChecker());
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}
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void ObjCAtSyncChecker::PreVisitObjCAtSynchronizedStmt(CheckerContext &C,
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const ObjCAtSynchronizedStmt *S) {
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const Expr *Ex = S->getSynchExpr();
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const GRState *state = C.getState();
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SVal V = state->getSVal(Ex);
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// Uninitialized value used for the mutex?
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if (isa<UndefinedVal>(V)) {
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if (ExplodedNode *N = C.GenerateSink()) {
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if (!BT_undef)
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BT_undef = new BuiltinBug("Uninitialized value used as mutex "
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"for @synchronized");
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EnhancedBugReport *report =
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new EnhancedBugReport(*BT_undef, BT_undef->getDescription(), N);
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report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, Ex);
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C.EmitReport(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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const GRState *notNullState, *nullState;
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llvm::tie(notNullState, nullState) = state->Assume(cast<DefinedSVal>(V));
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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.GenerateNode(nullState)) {
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if (!BT_null)
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BT_null = new BuiltinBug("Nil value used as mutex for @synchronized() "
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"(no synchronization will occur)");
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EnhancedBugReport *report =
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new EnhancedBugReport(*BT_null, BT_null->getDescription(), N);
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report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
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Ex);
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C.EmitReport(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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