1 files changed, 72 insertions, 0 deletions

diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
new file mode 100644
index 000000000000..fd372aafa50d
--- /dev/null
+++ b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
@@ -0,0 +1,72 @@
+// SmartPtrModeling.cpp - Model behavior of C++ smart pointers - 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 file defines a checker that models various aspects of
+// C++ smart pointer behavior.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Move.h"
+
+#include "clang/AST/ExprCXX.h"
+#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/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class SmartPtrModeling : public Checker<eval::Call> {
+  bool isNullAfterMoveMethod(const CallEvent &Call) const;
+
+public:
+  bool evalCall(const CallEvent &Call, CheckerContext &C) const;
+};
+} // end of anonymous namespace
+
+bool SmartPtrModeling::isNullAfterMoveMethod(const CallEvent &Call) const {
+  // TODO: Update CallDescription to support anonymous calls?
+  // TODO: Handle other methods, such as .get() or .release().
+  // But once we do, we'd need a visitor to explain null dereferences
+  // that are found via such modeling.
+  const auto *CD = dyn_cast_or_null<CXXConversionDecl>(Call.getDecl());
+  return CD && CD->getConversionType()->isBooleanType();
+}
+
+bool SmartPtrModeling::evalCall(const CallEvent &Call,
+                                CheckerContext &C) const {
+  if (!isNullAfterMoveMethod(Call))
+    return false;
+
+  ProgramStateRef State = C.getState();
+  const MemRegion *ThisR =
+      cast<CXXInstanceCall>(&Call)->getCXXThisVal().getAsRegion();
+
+  if (!move::isMovedFrom(State, ThisR)) {
+    // TODO: Model this case as well. At least, avoid invalidation of globals.
+    return false;
+  }
+
+  // TODO: Add a note to bug reports describing this decision.
+  C.addTransition(
+      State->BindExpr(Call.getOriginExpr(), C.getLocationContext(),
+                      C.getSValBuilder().makeZeroVal(Call.getResultType())));
+  return true;
+}
+
+void ento::registerSmartPtrModeling(CheckerManager &Mgr) {
+  Mgr.registerChecker<SmartPtrModeling>();
+}
+
+bool ento::shouldRegisterSmartPtrModeling(const LangOptions &LO) {
+  return LO.CPlusPlus;
+}