From: "René Scharfe" <l.s.r@web.de>
To: Git List <git@vger.kernel.org>
Cc: Junio C Hamano <gitster@pobox.com>
Subject: [PATCH v2 2/4] do full type check in BARF_UNLESS_COPYABLE
Date: Sun, 1 Jan 2023 22:11:20 +0100 [thread overview]
Message-ID: <4f161041-b299-f79a-e01b-cc00e2880850@web.de> (raw)
In-Reply-To: <9bc1bd74-f72c-1b43-df7c-950815babb03@web.de>
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>
---
git-compat-util.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/git-compat-util.h b/git-compat-util.h
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)
--
2.39.0
next prev parent reply other threads:[~2023-01-01 21:11 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-30 21:51 [PATCH 0/3] COPY_ARRAY, MOVE_ARRAY, DUP_ARRAY René Scharfe
2022-12-30 21:56 ` [PATCH 1/3] do full type check in COPY_ARRAY and MOVE_ARRAY René Scharfe
2023-01-01 3:03 ` Junio C Hamano
2023-01-01 3:59 ` Junio C Hamano
2023-01-01 7:41 ` René Scharfe
2023-01-01 10:45 ` René Scharfe
2023-01-01 12:11 ` Junio C Hamano
2023-01-01 12:32 ` René Scharfe
2023-01-01 12:46 ` Junio C Hamano
2022-12-30 22:02 ` [PATCH 2/3] add DUP_ARRAY René Scharfe
2022-12-30 22:03 ` [PATCH 3/3] use DUP_ARRAY René Scharfe
2023-01-01 21:05 ` [PATCH v2 0/4] COPY_ARRAY, MOVE_ARRAY, DUP_ARRAY René Scharfe
2023-01-01 21:08 ` [PATCH v2 1/4] factor out BARF_UNLESS_COPYABLE René Scharfe
2023-01-01 21:11 ` René Scharfe [this message]
2023-01-08 7:28 ` [PATCH v2 2/4] do full type check in BARF_UNLESS_COPYABLE Junio C Hamano
2023-01-08 10:10 ` René Scharfe
2023-01-09 4:27 ` Junio C Hamano
2023-01-09 18:08 ` Jeff Hostetler
2023-01-01 21:14 ` [PATCH v2 3/4] add DUP_ARRAY René Scharfe
2023-01-01 21:16 ` [PATCH v2 4/4] use DUP_ARRAY René Scharfe
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