DennisMelamed created this revision.
DennisMelamed added reviewers: alexfh, aaron.ballman, hokein, JonasToth.
Herald added subscribers: xazax.hun, mgorny.
[clang-tidy] Flag Classes Inheriting From Structs
Added a check which flags cases of a class inheriting from a struct, which can
cause unintended scope issues since struct members are public by default.
Patch by Dennis Melamed
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D52552
Files:
clang-tidy/misc/CMakeLists.txt
clang-tidy/misc/ClassInheritFromStructCheck.cpp
clang-tidy/misc/ClassInheritFromStructCheck.h
clang-tidy/misc/MiscTidyModule.cpp
docs/ReleaseNotes.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/misc-class-inherit-from-struct.rst
test/clang-tidy/misc-class-inherit-from-struct.cpp
Index: test/clang-tidy/misc-class-inherit-from-struct.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/misc-class-inherit-from-struct.cpp
@@ -0,0 +1,22 @@
+// RUN: %check_clang_tidy %s misc-class-inherit-from-struct %t
+
+struct A
+{
+ int a;
+};
+
+class B:A
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: classes should not inherit from structs [misc-class-inherit-from-struct]
+{
+ int b;
+};
+
+class C
+{
+ int c;
+};
+
+class D:C
+{
+ int d;
+};
Index: docs/clang-tidy/checks/misc-class-inherit-from-struct.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/misc-class-inherit-from-struct.rst
@@ -0,0 +1,18 @@
+.. title:: clang-tidy - misc-class-inherit-from-struct
+
+misc-class-inherit-from-struct
+==============================
+
+Finds instances of classes inheriting from structs. Structs are meant for
+storing data and are often used to maintain C compatibility. Having a class
+inherit from them can lead to confusion with what type of object is being
+dealt with. Additionally, the default public nature of struct members can
+lead to unintentional exposure of members.
+
+.. code-block:: c++
+
+ struct A {};
+ class B: public A {}; //throws an error, members of A might be
+ //unintentionally exposed
+ class C {};
+ class D: public C {}; //fine
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -159,6 +159,7 @@
llvm-include-order
llvm-namespace-comment
llvm-twine-local
+ misc-class-inherit-from-struct
misc-definitions-in-headers
misc-misplaced-const
misc-new-delete-overloads
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -106,6 +106,13 @@
Detects usage of magic numbers, numbers that are used as literals instead of
introduced via constants or symbols.
+- New :doc:`misc-class-inherit-from-struct
+ <clang-tidy/checks/misc-class-inherit-from-struct>` check.
+
+ Detects instances of classes inheriting from structs as that might lead to
+ unintended member access issues.
+
+
Improvements to include-fixer
-----------------------------
Index: clang-tidy/misc/MiscTidyModule.cpp
===================================================================
--- clang-tidy/misc/MiscTidyModule.cpp
+++ clang-tidy/misc/MiscTidyModule.cpp
@@ -10,6 +10,7 @@
#include "../ClangTidy.h"
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
+#include "ClassInheritFromStructCheck.h"
#include "DefinitionsInHeadersCheck.h"
#include "MisplacedConstCheck.h"
#include "NewDeleteOverloadsCheck.h"
@@ -30,6 +31,8 @@
class MiscModule : public ClangTidyModule {
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+ CheckFactories.registerCheck<ClassInheritFromStructCheck>(
+ "misc-class-inherit-from-struct");
CheckFactories.registerCheck<DefinitionsInHeadersCheck>(
"misc-definitions-in-headers");
CheckFactories.registerCheck<MisplacedConstCheck>("misc-misplaced-const");
Index: clang-tidy/misc/ClassInheritFromStructCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/misc/ClassInheritFromStructCheck.h
@@ -0,0 +1,35 @@
+//===--- ClassInheritFromStructCheck.h - clang-tidy--------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_CLASSINHERITFROMSTRUCTCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_CLASSINHERITFROMSTRUCTCHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Matches non-implicit classes which inherit from structs
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-class-inherit-from-struct.html
+class ClassInheritFromStructCheck : public ClangTidyCheck {
+public:
+ ClassInheritFromStructCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_CLASSINHERITFROMSTRUCTCHECK_H
Index: clang-tidy/misc/ClassInheritFromStructCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/misc/ClassInheritFromStructCheck.cpp
@@ -0,0 +1,31 @@
+//===--- ClassInheritFromStructCheck.cpp - clang-tidy----------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClassInheritFromStructCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+void ClassInheritFromStructCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(cxxRecordDecl(isClass(),unless(isImplicit()),isDerivedFrom(cxxRecordDecl(isStruct()))).bind("class"), this);
+}
+
+void ClassInheritFromStructCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedDecl = Result.Nodes.getNodeAs<CXXRecordDecl>("class");
+ diag(MatchedDecl->getLocation(), "classes should not inherit from structs");
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/misc/CMakeLists.txt
===================================================================
--- clang-tidy/misc/CMakeLists.txt
+++ clang-tidy/misc/CMakeLists.txt
@@ -1,6 +1,7 @@
set(LLVM_LINK_COMPONENTS support)
add_clang_library(clangTidyMiscModule
+ ClassInheritFromStructCheck.cpp
DefinitionsInHeadersCheck.cpp
MiscTidyModule.cpp
MisplacedConstCheck.cpp
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