fix <ctype.h> bugs on 64-bit machine

[Jeff Johnston]

Go ahead.  You might as well put in the parentheses as suggested by Craig.

-- Jeff J.

On 19/10/09 04:21 PM, Eric Blake wrote:
> Bruno Haible pointed out to me that on 64-bit machines, the use of isalpha
> (0x100000001LL) will cause an out-of-bounds array dereference, rather than
> returning the correct result of isalpha(1).  32-bit machines are immune.  All
> of this stems from our QoI effort to warn about raw char arguments.  OK to
> apply this fix?  I've verified that on 32-bit architectures, there is no
> difference in the generated code, with or without optimization.  I've also
> verified that 'gcc -Wall' still gives the desired warning.
>
> diff --git i/newlib/libc/include/ctype.h w/newlib/libc/include/ctype.h
> index e1d2d01..abc080e 100644
> --- i/newlib/libc/include/ctype.h
> +++ w/newlib/libc/include/ctype.h
> @@ -47,24 +47,32 @@ extern	__IMPORT char	*__ctype_ptr__;
>   #ifndef __cplusplus
>   /* These macros are intentionally written in a manner that will trigger
>      a gcc -Wall warning if the user mistakenly passes a 'char' instead
> -   of an int containing an 'unsigned char'.  */
> -#define	isalpha(__c)	((__ctype_ptr__+1)[__c]&(_U|_L))
> -#define	isupper(__c)	(((__ctype_ptr__+1)[__c]&(_U|_L))==_U)
> -#define	islower(__c)	(((__ctype_ptr__+1)[__c]&(_U|_L))==_L)
> -#define	isdigit(__c)	((__ctype_ptr__+1)[__c]&_N)
> -#define	isxdigit(__c)	((__ctype_ptr__+1)[__c]&(_X|_N))
> -#define	isspace(__c)	((__ctype_ptr__+1)[__c]&_S)
> -#define ispunct(__c)	((__ctype_ptr__+1)[__c]&_P)
> -#define isalnum(__c)	((__ctype_ptr__+1)[__c]&(_U|_L|_N))
> -#define isprint(__c)	((__ctype_ptr__+1)[__c]&(_P|_U|_L|_N|_B))
> -#define	isgraph(__c)	((__ctype_ptr__+1)[__c]&(_P|_U|_L|_N))
> -#define iscntrl(__c)	((__ctype_ptr__+1)[__c]&_C)
> +   of an int containing an 'unsigned char'.  Note that the sizeof will
> +   always be 1, which is what we want for mapping EOF to __ctype_ptr__[0];
> +   the use of a raw index inside the sizeof triggers the gcc warning if
> +   __c was of type char, and sizeof masks side effects of the extra __c.
> +   Meanwhile, the real index to __ctype_ptr__+1 must be cast to int,
> +   since isalpha(0x100000001LL) must equal isalpha(1), rather than being
> +   an out-of-bounds reference on a 64-bit machine.  */
> +#define __ctype_lookup(__c) ((__ctype_ptr__+sizeof""[__c])[(int)__c])
> +
> +#define	isalpha(__c)	(__ctype_lookup(__c)&(_U|_L))
> +#define	isupper(__c)	((__ctype_lookup(__c)&(_U|_L))==_U)
> +#define	islower(__c)	((__ctype_lookup(__c)&(_U|_L))==_L)
> +#define	isdigit(__c)	(__ctype_lookup(__c)&_N)
> +#define	isxdigit(__c)	(__ctype_lookup(__c)&(_X|_N))
> +#define	isspace(__c)	(__ctype_lookup(__c)&_S)
> +#define ispunct(__c)	(__ctype_lookup(__c)&_P)
> +#define isalnum(__c)	(__ctype_lookup(__c)&(_U|_L|_N))
> +#define isprint(__c)	(__ctype_lookup(__c)&(_P|_U|_L|_N|_B))
> +#define	isgraph(__c)	(__ctype_lookup(__c)&(_P|_U|_L|_N))
> +#define iscntrl(__c)	(__ctype_lookup(__c)&_C)
>
>   #if defined(__GNUC__)&&  \
>       (!defined(__STRICT_ANSI__) || __STDC_VERSION__>= 199901L)
>   #define isblank(__c) \
>     __extension__ ({ __typeof__ (__c) __x = (__c);		\
> -      ((__ctype_ptr__+1)[__x]&_B) || (__x) == '\t';})
> +        (__ctype_lookup(__x)&_B) || (int) (__x) == '\t';})
>   #endif
>
>
>
>