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
@@ -97,8 +97,14 @@ struct strbuf;
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# define BARF_UNLESS_AN_ARRAY(arr) \
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BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
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__typeof__(&(arr)[0])))
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+# define BARF_UNLESS_COPYABLE(dst, src) \
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+ BUILD_ASSERT_OR_ZERO(__builtin_types_compatible_p(__typeof__(*(dst)), \
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+ __typeof__(*(src))))
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#else
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# define BARF_UNLESS_AN_ARRAY(arr) 0
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+# define BARF_UNLESS_COPYABLE(dst, src) \
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+ BUILD_ASSERT_OR_ZERO(0 ? ((*(dst) = *(src)), 0) : \
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+ sizeof(*(dst)) == sizeof(*(src)))
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#endif
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/*
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* 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);
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#define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
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#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
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-#define BARF_UNLESS_COPYABLE(dst, src) \
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- BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src)))
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-
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#define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
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BARF_UNLESS_COPYABLE((dst), (src)))
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static inline void copy_array(void *dst, const void *src, size_t n, size_t size)