From 27cc7c57bb211b74bbcf0d2f2bb6618a759b75dc Mon Sep 17 00:00:00 2001 From: Tristan Partin Date: Wed, 29 Jul 2026 19:38:39 +0000 Subject: [PATCH v1 1/2] Add pg_attribute_counted_by() The counted_by attribute allows specifying that an array member (pointer or flexible array) of a struct is "counted by" another member of the same struct. Not only does this attribute make arrays a little more self-documenting, but it is also a hint to the compiler that can improve detection of object size information and provide better results in compile time diagnostics and runtime features like the array bound sanitizer. Signed-off-by: Tristan Partin --- src/include/c.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/include/c.h b/src/include/c.h index 20cfbac54e7..e83c1e391a7 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -297,6 +297,18 @@ extern "C++" #define pg_attribute_target(...) #endif +/* + * pg_attribute_counted_by allows specifying that an array is "counted by" + * another struct member. This provides the compiler to improve detection of + * object size information and provide better results in compile time + * diagnostics and runtime features like the array bound sanitizer. + */ +#if __has_attribute (counted_by) +#define pg_attribute_counted_by(...) __attribute__((counted_by(__VA_ARGS__))) +#else +#define pg_attribute_counted_by(...) +#endif + /* * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only * used in assert-enabled builds, to avoid compiler warnings about unused -- Tristan Partin https://tristan.partin.io