Clarify when __builtin_dynamic_object_size() is available. All our supported Clang versions support it. GCC 12 and later support it. Link to documentation for both.
Signed-off-by: Kees Cook <[email protected]> --- Cc: Miguel Ojeda <[email protected]> Cc: Nathan Chancellor <[email protected]> Cc: Nick Desaulniers <[email protected]> Cc: Bill Wendling <[email protected]> Cc: Justin Stitt <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Marco Elver <[email protected]> Cc: Przemek Kitszel <[email protected]> Cc: [email protected] --- include/linux/compiler_types.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 501cffddc2f4..20881cc761fa 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -449,6 +449,11 @@ struct ftrace_likely_data { /* * When the size of an allocated object is needed, use the best available * mechanism to find it. (For cases where sizeof() cannot be used.) + * + * Optional: only supported since gcc >= 12 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html + * clang: https://clang.llvm.org/docs/LanguageExtensions.html#evaluating-object-size */ #if __has_builtin(__builtin_dynamic_object_size) #define __struct_size(p) __builtin_dynamic_object_size(p, 0) -- 2.34.1
