[clang-tools-extra] [clang-tidy] Enable C23 support in modernize-use-nullptr (PR #89990)
Björn Svensson via cfe-commits
cfe-commits at lists.llvm.org
Wed Apr 24 14:15:49 PDT 2024
https://github.com/bjosv created https://github.com/llvm/llvm-project/pull/89990
C23 introduces the `nullptr` constant similar to C++11 which means that the checker `modernize-use-nullptr` can be used on C23 code as well.
This PR enables the checker to be run on C23 and adds testcases.
See N3042:
https://open-std.org/JTC1/SC22/WG14/www/docs/n3042.htm
>From 6e4e72cc371a5607616546c7b2ed7bf8386acd4c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Svensson?= <bjorn.a.svensson at est.tech>
Date: Wed, 24 Apr 2024 22:39:48 +0200
Subject: [PATCH] [clang-tidy] Enable C23 support in modernize-use-nullptr
C23 introduces the nullptr constant similar to C++11 which means that
the checker modernize-use-nullptr can be used on C23 code as well.
See N3042:
https://open-std.org/JTC1/SC22/WG14/www/docs/n3042.htm
---
.../clang-tidy/modernize/UseNullptrCheck.h | 2 +-
clang-tools-extra/docs/ReleaseNotes.rst | 4 +
.../checks/modernize/use-nullptr.rst | 2 +-
.../checkers/modernize/use-nullptr-c23.c | 139 ++++++++++++++++++
.../checkers/modernize/use-nullptr.c | 2 +-
5 files changed, 146 insertions(+), 3 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-c23.c
diff --git a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
index 6c32a4edb4ff96..f1591bae446579 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h
@@ -19,7 +19,7 @@ class UseNullptrCheck : public ClangTidyCheck {
bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
// FIXME this should be CPlusPlus11 but that causes test cases to
// erroneously fail.
- return LangOpts.CPlusPlus;
+ return LangOpts.CPlusPlus || LangOpts.C23;
}
void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 7095c564444fe6..953453219221e8 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -253,6 +253,10 @@ Changes in existing checks
<clang-tidy/checks/modernize/use-override>` check to also remove any trailing
whitespace when deleting the ``virtual`` keyword.
+- Improved :doc:`modernize-use-nullptr
+ <clang-tidy/checks/modernize/use-nullptr>` check to include support for
+ ``C23``, which also has introduced the ``nullptr`` keyword.
+
- Improved :doc:`modernize-use-using <clang-tidy/checks/modernize/use-using>`
check by adding support for detection of typedefs declared on function level.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize/use-nullptr.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize/use-nullptr.rst
index 5e1ba858adf3a9..25e17fee0a3d61 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/modernize/use-nullptr.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/modernize/use-nullptr.rst
@@ -4,7 +4,7 @@ modernize-use-nullptr
=====================
The check converts the usage of null pointer constants (e.g. ``NULL``, ``0``)
-to use the new C++11 ``nullptr`` keyword.
+to use the new C++11 and C23 ``nullptr`` keyword.
Example
-------
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-c23.c b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-c23.c
new file mode 100644
index 00000000000000..6fb879b91e41c1
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr-c23.c
@@ -0,0 +1,139 @@
+// RUN: %check_clang_tidy %s modernize-use-nullptr %t -- -- -std=c23
+
+#define NULL 0
+
+void test_assignment() {
+ int *p1 = 0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr [modernize-use-nullptr]
+ // CHECK-FIXES: int *p1 = nullptr;
+ p1 = 0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
+ // CHECK-FIXES: p1 = nullptr;
+
+ int *p2 = NULL;
+ // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
+ // CHECK-FIXES: int *p2 = nullptr;
+
+ p2 = p1;
+ // CHECK-FIXES: p2 = p1;
+
+ const int null = 0;
+ int *p3 = &null;
+
+ p3 = NULL;
+ // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use nullptr
+ // CHECK-FIXES: p3 = nullptr;
+
+ int *p4 = p3;
+
+ int i1 = 0;
+
+ int i2 = NULL;
+
+ int i3 = null;
+
+ int *p5, *p6, *p7;
+ p5 = p6 = p7 = NULL;
+ // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use nullptr
+ // CHECK-FIXES: p5 = p6 = p7 = nullptr;
+}
+
+void test_function(int *p) {}
+
+void test_function_no_ptr_param(int i) {}
+
+void test_function_call() {
+ test_function(0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
+ // CHECK-FIXES: test_function(nullptr);
+
+ test_function(NULL);
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use nullptr
+ // CHECK-FIXES: test_function(nullptr);
+
+ test_function_no_ptr_param(0);
+}
+
+char *test_function_return1() {
+ return 0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
+ // CHECK-FIXES: return nullptr;
+}
+
+void *test_function_return2() {
+ return NULL;
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
+ // CHECK-FIXES: return nullptr;
+}
+
+int test_function_return4() {
+ return 0;
+}
+
+int test_function_return5() {
+ return NULL;
+}
+
+int *test_function_return_cast1() {
+ return(int)0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use nullptr
+ // CHECK-FIXES: return nullptr;
+}
+
+int *test_function_return_cast2() {
+#define RET return
+ RET(int)0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: use nullptr
+ // CHECK-FIXES: RET nullptr;
+#undef RET
+}
+
+// Test parentheses expressions resulting in a nullptr.
+int *test_parentheses_expression1() {
+ return(0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
+ // CHECK-FIXES: return(nullptr);
+}
+
+int *test_parentheses_expression2() {
+ return((int)(0.0f));
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use nullptr
+ // CHECK-FIXES: return(nullptr);
+}
+
+int *test_nested_parentheses_expression() {
+ return((((0))));
+ // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use nullptr
+ // CHECK-FIXES: return((((nullptr))));
+}
+
+void test_const_pointers() {
+ const int *const_p1 = 0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
+ // CHECK-FIXES: const int *const_p1 = nullptr;
+ const int *const_p2 = NULL;
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
+ // CHECK-FIXES: const int *const_p2 = nullptr;
+ const int *const_p3 = (int)0;
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
+ // CHECK-FIXES: const int *const_p3 = nullptr;
+ const int *const_p4 = (int)0.0f;
+ // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: use nullptr
+ // CHECK-FIXES: const int *const_p4 = nullptr;
+}
+
+void test_nested_implicit_cast_expr() {
+ int func0(void*, void*);
+ int func1(int, void*, void*);
+
+ (double)func1(0, 0, 0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use nullptr
+ // CHECK-MESSAGES: :[[@LINE-2]]:23: warning: use nullptr
+ // CHECK-FIXES: (double)func1(0, nullptr, nullptr);
+ (double)func1(func0(0, 0), 0, 0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: use nullptr
+ // CHECK-MESSAGES: :[[@LINE-2]]:26: warning: use nullptr
+ // CHECK-MESSAGES: :[[@LINE-3]]:30: warning: use nullptr
+ // CHECK-MESSAGES: :[[@LINE-4]]:33: warning: use nullptr
+ // CHECK-FIXES: (double)func1(func0(nullptr, nullptr), nullptr, nullptr);
+}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr.c b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr.c
index c2ccbbd8117152..1218b837199c0c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr.c
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-nullptr.c
@@ -1,4 +1,4 @@
-// RUN: clang-tidy %s -checks=-*,modernize-use-nullptr -- | count 0
+// RUN: clang-tidy %s -checks=-*,modernize-use-nullptr -- -std=c17 | count 0
// Note: this test expects no diagnostics, but FileCheck cannot handle that,
// hence the use of | count 0.
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