[clang-tidy] check for __func__/__FUNCTION__ in lambdas

Add a clang-tidy check for using func__/FUNCTION__ inside lambdas. This
evaluates to the string operator(), which is almost never useful and almost
certainly not what the author intended.

Patch by Bryce Liu!

Differential Revision: https://reviews.llvm.org/D33497

llvm-svn: 304570

1 files changed, 41 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/misc-lambda-function-name.cpp b/clang-tools-extra/test/clang-tidy/misc-lambda-function-name.cpp
new file mode 100644
index 00000000000..cc5aa2b5a0b
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/misc-lambda-function-name.cpp
@@ -0,0 +1,41 @@
+// RUN: %check_clang_tidy %s misc-lambda-function-name %t
+
+void Foo(const char* a, const char* b, int c) {}
+
+#define FUNC_MACRO Foo(__func__, "", 0)
+#define FUNCTION_MACRO Foo(__FUNCTION__, "", 0)
+#define EMBED_IN_ANOTHER_MACRO1 FUNC_MACRO
+
+void Positives() {
+  [] { __func__; }();
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: inside a lambda, '__func__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [misc-lambda-function-name]
+  [] { __FUNCTION__; }();
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: inside a lambda, '__FUNCTION__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [misc-lambda-function-name]
+  [] { FUNC_MACRO; }();
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: inside a lambda, '__func__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [misc-lambda-function-name]
+  [] { FUNCTION_MACRO; }();
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: inside a lambda, '__FUNCTION__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [misc-lambda-function-name]
+  [] { EMBED_IN_ANOTHER_MACRO1; }();
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: inside a lambda, '__func__' expands to the name of the function call operator; consider capturing the name of the enclosing function explicitly [misc-lambda-function-name]
+}
+
+#define FUNC_MACRO_WITH_FILE_AND_LINE Foo(__func__, __FILE__, __LINE__)
+#define FUNCTION_MACRO_WITH_FILE_AND_LINE Foo(__FUNCTION__, __FILE__, __LINE__)
+#define EMBED_IN_ANOTHER_MACRO2 FUNC_MACRO_WITH_FILE_AND_LINE
+
+void Negatives() {
+  __func__;
+  __FUNCTION__;
+
+  // __PRETTY_FUNCTION__ should not trigger a warning because its value is
+  // actually potentially useful.
+  __PRETTY_FUNCTION__;
+  [] { __PRETTY_FUNCTION__; }();
+
+  // Don't warn if __func__/__FUNCTION is used inside a macro that also uses
+  // __FILE__ and __LINE__, on the assumption that __FILE__ and __LINE__ will
+  // be useful even if __func__/__FUNCTION__ is not.
+  [] { FUNC_MACRO_WITH_FILE_AND_LINE; }();
+  [] { FUNCTION_MACRO_WITH_FILE_AND_LINE; }();
+  [] { EMBED_IN_ANOTHER_MACRO2; }();
+}