| Message ID | 20241203-is_constexpr-refactor-v1-6-4e4cbaecc216@wanadoo.fr (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | compiler.h: refactor __is_constexpr() into is_const{,_true,_false}() | expand |
From: Vincent Mailhol > Sent: 02 December 2024 17:33 > > From: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > > is_const() is a one to one replacement of __is_constexpr(). Do the > replacement so that __is_constexpr() can be removed. > > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > --- > include/linux/fortify-string.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h > index 0d99bf11d260a3482bbe46e35c7553c0ccfb8b94..e3f2f772c5439ef71eb4a904b4ce27956bc69743 100644 > --- a/include/linux/fortify-string.h > +++ b/include/linux/fortify-string.h > @@ -254,8 +254,8 @@ __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size > * Returns number of characters in @p (NOT including the final NUL). > * > */ > -#define strlen(p) \ > - __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)), \ > +#define strlen(p) \ > + __builtin_choose_expr(is_const(__builtin_strlen(p)), \ > __builtin_strlen(p), __fortify_strlen(p)) I'm sure Linus suggested a way of doing that without replicating the __builtin_strlen(). Indeed it may be valid to do: len = __builtin_strlen(p); __builtin_constant_p(len) ? len : __fortify_strlen(p); David > __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1) > __kernel_size_t __fortify_strlen(const char * const POS p) > > -- > 2.45.2 > > - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Thu. 5 Dec. 2024 at 03:58, David Laight <David.Laight@aculab.com> wrote: > From: Vincent Mailhol > > Sent: 02 December 2024 17:33 > > > > From: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > > > > is_const() is a one to one replacement of __is_constexpr(). Do the > > replacement so that __is_constexpr() can be removed. > > > > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > > --- > > include/linux/fortify-string.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h > > index 0d99bf11d260a3482bbe46e35c7553c0ccfb8b94..e3f2f772c5439ef71eb4a904b4ce27956bc69743 100644 > > --- a/include/linux/fortify-string.h > > +++ b/include/linux/fortify-string.h > > @@ -254,8 +254,8 @@ __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size > > * Returns number of characters in @p (NOT including the final NUL). > > * > > */ > > -#define strlen(p) \ > > - __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)), \ > > +#define strlen(p) \ > > + __builtin_choose_expr(is_const(__builtin_strlen(p)), \ > > __builtin_strlen(p), __fortify_strlen(p)) > > I'm sure Linus suggested a way of doing that without replicating > the __builtin_strlen(). > > Indeed it may be valid to do: > len = __builtin_strlen(p); > __builtin_constant_p(len) ? len : __fortify_strlen(p); Then, wouldn't it be better for strlen() to be an inline function instead of a macro? __FORTIFY_INLINE __kernel_size_t strlen(const char *p) { __kernel_size_t ret = __builtin_strlen(p); if (__builtin_constant_p(ret)) return ret; return __fortify_strlen(p); } I tested it and it worked on an allyesconfig. So if I receive no objections, strlen() will become an inline function in v2. Yours sincerely, Vincent Mailhol
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index 0d99bf11d260a3482bbe46e35c7553c0ccfb8b94..e3f2f772c5439ef71eb4a904b4ce27956bc69743 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -254,8 +254,8 @@ __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size * Returns number of characters in @p (NOT including the final NUL). * */ -#define strlen(p) \ - __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)), \ +#define strlen(p) \ + __builtin_choose_expr(is_const(__builtin_strlen(p)), \ __builtin_strlen(p), __fortify_strlen(p)) __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1) __kernel_size_t __fortify_strlen(const char * const POS p)