do full type check in BARF_UNLESS_COPYABLE
Use __builtin_types_compatible_p to perform a full type check if possible. Otherwise fall back to the old size comparison, but add a non-evaluated assignment to catch more type mismatches. It doesn't flag copies between arrays with different signedness, but that's as close to a full type check as it gets without the builtin, as far as I can see. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
René Scharfe committed
Jan 1, 2023 at 22:11 UTC
08e8c266653a486cc441ec031136875bf579f054
1 file changed
+6
-3
git-compat-util.h
+6
-3
index 940d03150c..e81bb14fc9 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -97,8 +97,14 @@ struct strbuf;
# define BARF_UNLESS_AN_ARRAY(arr) \
BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
__typeof__(&(arr)[0])))
+# define BARF_UNLESS_COPYABLE(dst, src) \
+ BUILD_ASSERT_OR_ZERO(__builtin_types_compatible_p(__typeof__(*(dst)), \
+ __typeof__(*(src))))
#else
# define BARF_UNLESS_AN_ARRAY(arr) 0
+# define BARF_UNLESS_COPYABLE(dst, src) \
+ BUILD_ASSERT_OR_ZERO(0 ? ((*(dst) = *(src)), 0) : \
+ sizeof(*(dst)) == sizeof(*(src)))
#endif
/*
* ARRAY_SIZE - get the number of elements in a visible array
@@ -1093,9 +1099,6 @@ int xstrncmpz(const char *s, const char *t, size_t len);
#define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
-#define BARF_UNLESS_COPYABLE(dst, src) \
- BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src)))
-
#define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
BARF_UNLESS_COPYABLE((dst), (src)))
static inline void copy_array(void *dst, const void *src, size_t n, size_t size)