@@ -225,6 +225,16 @@
#define __pure __attribute__((__pure__))
/*
+ * Note: Since this macro makes use of the "stringification operator" `#`, a
+ * quoted string literal should not be passed to it. eg.
+ * prefer:
+ * __section(.foo)
+ * to:
+ * __section(".foo")
+ * unless the section name is dynamically built up, in which case the
+ * verbose __attribute__((__section__(".foo" x))) should be preferred.
+ * See also: https://bugs.llvm.org/show_bug.cgi?id=42950
+ *
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute
* clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate
GCC unescapes escaped string section names while Clang does not. Because __section uses the `#` stringification operator for the section name, it doesn't need to be escaped. Instead, we should: 1. Prefer __section(.section_name_no_quotes). 2. Only use __attribute__((__section__(".section"))) when creating the section name via C preprocessor (see the definition of __define_initcall in arch/um/include/shared/init.h). This antipattern was found with: $ grep -e __section\(\" -e __section__\(\" -r See the discussions in: Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2 Link: https://github.com/ClangBuiltLinux/linux/issues/619 Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- include/linux/compiler_attributes.h | 10 ++++++++++ 1 file changed, 10 insertions(+) -- 2.23.0.187.g17f5b7556c-goog