[clang] [clang][dataflow] Add matchers for smart pointer accessors to be cached (PR #120102)

[Jan Voung via cfe-commits]

================
@@ -0,0 +1,194 @@
+//===- unittests/Analysis/FlowSensitive/SmartPointerAccessorCachingTest.cpp ==//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/FlowSensitive/SmartPointerAccessorCaching.h"
+
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Testing/TestAST.h"
+#include "llvm/ADT/StringRef.h"
+#include "gtest/gtest.h"
+
+namespace clang::dataflow {
+namespace {
+
+using clang::ast_matchers::match;
+
+template <typename MatcherT>
+bool matches(llvm::StringRef Decls, llvm::StringRef TestInput,
+             MatcherT Matcher) {
+  TestAST InputAST(Decls.str() + TestInput.str());
+  return !match(Matcher, InputAST.context()).empty();
+}
+
+TEST(SmartPointerAccessorCachingTest, MatchesClassWithStarArrowGet) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    template <class T>
+    struct unique_ptr {
+      T* operator->() const;
+      T& operator*() const;
+      T* get() const;
+    };
+    }  // namespace std
+
+    template <class T>
+    using UniquePtrAlias = std::unique_ptr<T>;
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_TRUE(matches(Decls,
+                      "int target(std::unique_ptr<S> P) { return (*P).i; }",
+                      isSmartPointerLikeOperatorStar()));
+  EXPECT_TRUE(matches(Decls,
+                      "int target(std::unique_ptr<S> P) { return P->i; }",
+                      isSmartPointerLikeOperatorArrow()));
+  EXPECT_TRUE(matches(Decls,
+                      "int target(std::unique_ptr<S> P) { return P.get()->i; }",
+                      isSmartPointerLikeGetMethodCall()));
+
+  EXPECT_TRUE(matches(Decls, "int target(UniquePtrAlias<S> P) { return P->i; }",
+                      isSmartPointerLikeOperatorArrow()));
+}
+
+TEST(SmartPointerAccessorCachingTest, NoMatchIfUnexpectedReturnTypes) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    // unique_ptr isn't really like this, but we aren't matching by name
+    template <class T, class U>
+    struct unique_ptr {
+      U* operator->() const;
+      T& operator*() const;
+      T* get() const;
+    };
+    }  // namespace std
+
+    struct S { int i; };
+    struct T { int j; };
+  )cc");
+
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S, T> P) { return (*P).i; }",
+                       isSmartPointerLikeOperatorStar()));
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S, T> P) { return P->j; }",
+                       isSmartPointerLikeOperatorArrow()));
+  // The class matching arguably accidentally matches, just because the
+  // instantiation is with S, S. Hopefully doesn't happen too much in real code
+  // with such operator* and operator-> overloads.
+  EXPECT_TRUE(matches(Decls,
+                      "int target(std::unique_ptr<S, S> P) { return P->i; }",
+                      isSmartPointerLikeOperatorArrow()));
+}
+
+TEST(SmartPointerAccessorCachingTest, NoMatchIfBinaryStar) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    template <class T>
+    struct unique_ptr {
+      T* operator->() const;
+      T& operator*(int x) const;
+      T* get() const;
+    };
+    }  // namespace std
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_FALSE(
+      matches(Decls, "int target(std::unique_ptr<S> P) { return (P * 10).i; }",
+              isSmartPointerLikeOperatorStar()));
+}
+
+TEST(SmartPointerAccessorCachingTest, NoMatchIfNoConstOverloads) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    template <class T>
+    struct unique_ptr {
+      T* operator->();
+      T& operator*();
+      T* get();
+    };
+    }  // namespace std
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S> P) { return (*P).i; }",
+                       isSmartPointerLikeOperatorStar()));
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S> P) { return P->i; }",
+                       isSmartPointerLikeOperatorArrow()));
+  EXPECT_FALSE(
+      matches(Decls, "int target(std::unique_ptr<S> P) { return P.get()->i; }",
+              isSmartPointerLikeGetMethodCall()));
+}
+
+TEST(SmartPointerAccessorCachingTest, NoMatchIfNoStarMethod) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    template <class T>
+    struct unique_ptr {
+      T* operator->();
+      T* get();
+    };
+    }  // namespace std
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S> P) { return P->i; }",
+                       isSmartPointerLikeOperatorArrow()));
+  EXPECT_FALSE(matches(Decls,
+                       "int target(std::unique_ptr<S> P) { return P->i; }",
+                       isSmartPointerLikeGetMethodCall()));
+}
+
+TEST(SmartPointerAccessorCachingTest, MatchesWithValueAndNonConstOverloads) {
+  llvm::StringRef Decls(R"cc(
+    namespace std {
+    template <class T>
+    struct optional {
+      const T* operator->() const;
+      T* operator->();
+      const T& operator*() const;
+      T& operator*();
+      const T& value() const;
+      T& value();
+    };
+    }  // namespace std
+
+    struct S { int i; };
+  )cc");
+
+  EXPECT_TRUE(matches(
+      Decls, "int target(std::optional<S> &NonConst) { return (*NonConst).i; }",
+      isSmartPointerLikeOperatorStar()));
+  EXPECT_TRUE(matches(
+      Decls, "int target(const std::optional<S> &Const) { return (*Const).i; }",
+      isSmartPointerLikeOperatorStar()));
+  EXPECT_TRUE(matches(
+      Decls, "int target(std::optional<S> &NonConst) { return NonConst->i; }",
+      isSmartPointerLikeOperatorArrow()));
+  EXPECT_TRUE(matches(
+      Decls, "int target(const std::optional<S> &Const) { return Const->i; }",
+      isSmartPointerLikeOperatorArrow()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(std::optional<S> &NonConst) { return NonConst.value().i; }",
+      isSmartPointerLikeValueMethodCall()));
+  EXPECT_TRUE(matches(
+      Decls,
+      "int target(const std::optional<S> &Const) { return Const.value().i; }",
+      isSmartPointerLikeValueMethodCall()));
+}
+
+} // namespace
+} // namespace clang::dataflow
----------------
jvoung wrote:

For some reason clang-format wants to remove that newline =(

https://github.com/llvm/llvm-project/pull/120102