Re: new offset outside bounds of constant string warning

Re: new offset outside bounds of constant string warning

[Ben Elliston]

On Manuel's recommendation, I have backed out revision 145102 for the
time being.  If someone wishes to have another go at it, the code is in
svn.

Cheers, Ben

--
Ben Elliston <bje@au.ibm.com>
Australia Development Lab, IBM

Re: new offset outside bounds of constant string warning

[H.J. Lu]

2009/4/27 Ben Elliston <bje@au1.ibm.com>:
> On Manuel's recommendation, I have backed out revision 145102 for the
> time being.  If someone wishes to have another go at it, the code is in
> svn.
>
> Cheers, Ben

You should use "patch -E" apply any patches. I checked in revision 14689
 to remove the empty g++.dg/warn/pr35652.C and gcc.dg/pr35652.c.

-- 
H.J.

Re: new offset outside bounds of constant string warning

[Manuel López-Ibáñez]

2009/4/28 H.J. Lu <hjl.tools@gmail.com>:
> 2009/4/27 Ben Elliston <bje@au1.ibm.com>:
>> On Manuel's recommendation, I have backed out revision 145102 for the
>> time being.  If someone wishes to have another go at it, the code is in
>> svn.
>>
>> Cheers, Ben
>
> You should use "patch -E" apply any patches. I checked in revision 14689
>  to remove the empty g++.dg/warn/pr35652.C and gcc.dg/pr35652.c.

The tests could stay as XFAILED. Perhaps is too late...

Cheers,

Manuel.

Re: new offset outside bounds of constant string warning

[Ian Lance Taylor]

Manuel López-Ibáñez <lopezibanez@gmail.com> writes:

> I authored the patch, HJ just committed it. I cannot think any trivial
> way to fix this and I don't have much time to investigate. The PR is
> already reopened, so I think the patch should be reverted. Probably we
> warn too early now but the above testcase seems specially difficult to
> handle.

We may be able to handle it in a manner similar to skip_evaluation in
the C++ frontend.  When we see a conditional whose test evaluates to a
constant, then while processing the false branch we can note that the
code will never be executed, and suppress immediate warnings, and set
TREE_NO_WARNING to suppress future warnings.

Ian

Re: new offset outside bounds of constant string warning

[Manuel López-Ibáñez]

2009/4/23 Ben Elliston <bje@au1.ibm.com>:
> Hi HJ
>
> According to svn annotate, it was you who authored the new 'offset
> outside bounds of constant string warning' warning in GCC (well, I think
> so, anyway).  The compiler now complains about some code in the C++
> demangler:
>
> /home/bje/source/gcc-trunk/libiberty/cplus-dem.c:2651: warning: offset ‘3’ outside bounds of constant string
>
> I tracked this down to the definition of strspn used on my Linux system:
>
> #   define strspn(s, accept) \
>  __extension__                                                               \
>  ({ char __a0, __a1, __a2;                                                   \
>     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)             \
>      ? ((__builtin_constant_p (s) && __string2_1bptr_p (s))                  \
>         ? __builtin_strspn (s, accept)                                       \
>         : ((__a0 = ((__const char *) (accept))[0], __a0 == '\0')             \
>            ? ((void) (s), 0)                                                 \
>            : ((__a1 = ((__const char *) (accept))[1], __a1 == '\0')          \
>               ? __strspn_c1 (s, __a0)                                        \
>               : ((__a2 = ((__const char *) (accept))[2], __a2 == '\0')       \
>                  ? __strspn_c2 (s, __a0, __a1)                               \
>                  : (((__const char *) (accept))[3] == '\0'                   \
>                     ? __strspn_c3 (s, __a0, __a1, __a2)                      \
>                     : __builtin_strspn (s, accept))))))                      \
>      : __builtin_strspn (s, accept)); })
>
> Is this something you can fix?
>

I authored the patch, HJ just committed it. I cannot think any trivial
way to fix this and I don't have much time to investigate. The PR is
already reopened, so I think the patch should be reverted. Probably we
warn too early now but the above testcase seems specially difficult to
handle.

With the revert, it would useful to add one of the failing testcases
to the testsuite, to avoid repeating this situation.

Cheers,

Manuel.

Re: new offset outside bounds of constant string warning

[Jakub Jelinek]

On Thu, Apr 23, 2009 at 03:50:12PM +1000, Ben Elliston wrote:
> According to svn annotate, it was you who authored the new 'offset
> outside bounds of constant string warning' warning in GCC (well, I think
> so, anyway).  The compiler now complains about some code in the C++
> demangler:
> 
> /home/bje/source/gcc-trunk/libiberty/cplus-dem.c:2651: warning: offset ???3??? outside bounds of constant string

It was actually Manuel, H.J. just committed the patch.
It has been reverted on the 4.4 branch already, and unless something is done
on the trunk I'd think it should be reverted on the trunk as well.

	Jakub

new offset outside bounds of constant string warning

[Ben Elliston]

Hi HJ

According to svn annotate, it was you who authored the new 'offset
outside bounds of constant string warning' warning in GCC (well, I think
so, anyway).  The compiler now complains about some code in the C++
demangler:

/home/bje/source/gcc-trunk/libiberty/cplus-dem.c:2651: warning: offset ‘3’ outside bounds of constant string

I tracked this down to the definition of strspn used on my Linux system:

#   define strspn(s, accept) \
  __extension__                                                               \
  ({ char __a0, __a1, __a2;                                                   \
     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)             \
      ? ((__builtin_constant_p (s) && __string2_1bptr_p (s))                  \
         ? __builtin_strspn (s, accept)                                       \
         : ((__a0 = ((__const char *) (accept))[0], __a0 == '\0')             \
            ? ((void) (s), 0)                                                 \
            : ((__a1 = ((__const char *) (accept))[1], __a1 == '\0')          \
               ? __strspn_c1 (s, __a0)                                        \
               : ((__a2 = ((__const char *) (accept))[2], __a2 == '\0')       \
                  ? __strspn_c2 (s, __a0, __a1)                               \
                  : (((__const char *) (accept))[3] == '\0'                   \
                     ? __strspn_c3 (s, __a0, __a1, __a2)                      \
                     : __builtin_strspn (s, accept))))))                      \
      : __builtin_strspn (s, accept)); })

Is this something you can fix?

Thanks, Ben