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| author | Edward Thomson <ethomson@edwardthomson.com> | 2019-01-20 13:00:53 +0000 |
|---|---|---|
| committer | Edward Thomson <ethomson@edwardthomson.com> | 2019-01-20 13:00:53 +0000 |
| commit | f04f1c7eedf2081c35dda71594a6072c6cc65694 (patch) | |
| tree | 6e3a52c82f2993fae4ecef0715f6b36c0471171b /src/integer.h | |
| parent | 2848923a2f5099b6d105b0b30212134d84377dee (diff) | |
| download | libgit2-f04f1c7eedf2081c35dda71594a6072c6cc65694.tar.gz | |
add with overflow intrinsics: simplify tests
Use the smallest unsigned type that is equivalent to `size_t` to
simplify the conditionals. Error if we're on a system that we believe
offers builtins but we cannot determine which one to use.
Diffstat (limited to 'src/integer.h')
| -rw-r--r-- | src/integer.h | 44 |
1 files changed, 18 insertions, 26 deletions
diff --git a/src/integer.h b/src/integer.h index 98d2b73c5..f6642ca23 100644 --- a/src/integer.h +++ b/src/integer.h @@ -58,32 +58,24 @@ GIT_INLINE(bool) git__add_uint64_overflow(uint64_t *out, uint64_t one, uint64_t #if (__has_builtin(__builtin_add_overflow) || \ (defined(__GNUC__) && (__GNUC__ >= 5))) -/* - * Even though __builtin_{add,mul}_overflow should be able to handle all - * possible cases (since it can accept any type), under some configurations - * clang would need a dependency on compiler-rt. In order to avoid that, we - * attempt to choose one of the explicit unsigned long long / unsigned long - * versions of the intrinsics if possible. Unfortunately, unsigned long long - * and unsigned long are still different types to the compiler, so we need to - * still do some additional sniffing to prevent MinGW 64 from choosing the - * wrong version and triggering compiler warnings. - */ -# if (SIZE_MAX == ULLONG_MAX) && (ULONG_MAX == ULLONG_MAX) && defined(_WIN64) -# define git__add_sizet_overflow(out, one, two) \ - __builtin_uaddll_overflow(one, two, out) -# define git__multiply_sizet_overflow(out, one, two) \ - __builtin_umulll_overflow(one, two, out) -# elif (SIZE_MAX == ULONG_MAX) && (ULONG_MAX == ULLONG_MAX) -# define git__add_sizet_overflow(out, one, two) \ - __builtin_uaddl_overflow(one, two, out) -# define git__multiply_sizet_overflow(out, one, two) \ - __builtin_umull_overflow(one, two, out) -# else -# define git__add_sizet_overflow(out, one, two) \ - __builtin_add_overflow(one, two, out) -# define git__multiply_sizet_overflow(out, one, two) \ - __builtin_mul_overflow(one, two, out) -# endif +# if (SIZE_MAX == UINT_MAX) +# define git__add_sizet_overflow(out, one, two) \ + __builtin_uadd_overflow(one, two, out) +# define git__multiply_sizet_overflow(out, one, two) \ + __builtin_umul_overflow(one, two, out) +# elif (SIZE_MAX == ULONG_MAX) +# define git__add_sizet_overflow(out, one, two) \ + __builtin_uaddl_overflow(one, two, out) +# define git__multiply_sizet_overflow(out, one, two) \ + __builtin_umull_overflow(one, two, out) +# elif (SIZE_MAX == ULLONG_MAX) +# define git__add_sizet_overflow(out, one, two) \ + __builtin_uaddll_overflow(one, two, out) +# define git__multiply_sizet_overflow(out, one, two) \ + __builtin_umulll_overflow(one, two, out) +# else +# error compiler has add with overflow intrinsics but SIZE_MAX is unknown +# endif #else |