1 files changed, 62 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/CXXSelfAssignmentChecker.cpp b/lib/StaticAnalyzer/Checkers/CXXSelfAssignmentChecker.cpp
new file mode 100644
index 000000000000..7631322d255b
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/CXXSelfAssignmentChecker.cpp
@@ -0,0 +1,62 @@
+//=== CXXSelfAssignmentChecker.cpp -----------------------------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines CXXSelfAssignmentChecker, which tests all custom defined
+// copy and move assignment operators for the case of self assignment, thus
+// where the parameter refers to the same location where the this pointer
+// points to. The checker itself does not do any checks at all, but it
+// causes the analyzer to check every copy and move assignment operator twice:
+// once for when 'this' aliases with the parameter and once for when it may not.
+// It is the task of the other enabled checkers to find the bugs in these two
+// different cases.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class CXXSelfAssignmentChecker : public Checker<check::BeginFunction> {
+public:
+  CXXSelfAssignmentChecker();
+  void checkBeginFunction(CheckerContext &C) const;
+};
+}
+
+CXXSelfAssignmentChecker::CXXSelfAssignmentChecker() {}
+
+void CXXSelfAssignmentChecker::checkBeginFunction(CheckerContext &C) const {
+  if (!C.inTopFrame())
+    return;
+  const auto *LCtx = C.getLocationContext();
+  const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());
+  if (!MD)
+    return;
+  if (!MD->isCopyAssignmentOperator() && !MD->isMoveAssignmentOperator())
+    return;
+  auto &State = C.getState();
+  auto &SVB = C.getSValBuilder();
+  auto ThisVal =
+      State->getSVal(SVB.getCXXThis(MD, LCtx->getCurrentStackFrame()));
+  auto Param = SVB.makeLoc(State->getRegion(MD->getParamDecl(0), LCtx));
+  auto ParamVal = State->getSVal(Param);
+  ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal);
+  C.addTransition(SelfAssignState);
+  ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal);
+  C.addTransition(NonSelfAssignState);
+}
+
+void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) {
+  Mgr.registerChecker<CXXSelfAssignmentChecker>();
+}