[Ping] Fix gcc/gcov.c and libgcc/libgcov.c to fix build on VxWorks

On 06/11/2012 08:01 AM, Paolo Bonzini wrote:
> Il 11/06/2012 13:56, rbmj ha scritto:
>>>> ... simply pass the extra mode argument in unconditionally,
>>>> as it should be transparent to the function and ignored if it is
>>>> variadic (I'm no expert on calling conventions though).
> Yes, please do this.
Done.
> VxWorks should define TARGET_POSIX_IO if it has both access and mkdir. 
> Please add it to gcc/config/vxworks.h if this is the case.

I misspoke in my earlier email - sorry for my lack of attention to 
detail.  The issue is that
VxWorks does *not* have a two argument mkdir().  It does have 
TARGET_POSIX_IO.  Undefing TARGET_POSIX_IO seems non-optimal as it 
disables some functionality that can still be implemented, just omitting 
the mode argument.  With this in mind, I defined MKDIR_SINGLE_ARG in 
gcc/config/vxworks.h, and then added a check for this define.  This is a 
slightly less ugly solution than I had earlier.

An updated patch is attached.  It's in git format-patch format, so the 
commit message is at the top.

Robert

On 06/12/2012 08:16 AM, rbmj wrote:
> On 06/11/2012 08:01 AM, Paolo Bonzini wrote:
>> VxWorks should define TARGET_POSIX_IO if it has both access and 
>> mkdir. Please add it to gcc/config/vxworks.h if this is the case.
>
> I misspoke in my earlier email - sorry for my lack of attention to 
> detail.  The issue is that
> VxWorks does *not* have a two argument mkdir().  It does have 
> TARGET_POSIX_IO.  Undefing TARGET_POSIX_IO seems non-optimal as it 
> disables some functionality that can still be implemented, just 
> omitting the mode argument.  With this in mind, I defined 
> MKDIR_SINGLE_ARG in gcc/config/vxworks.h, and then added a check for 
> this define.  This is a slightly less ugly solution than I had earlier.
>
> An updated patch is attached.  It's in git format-patch format, so the 
> commit message is at the top.

There is an alternate solution- I could use fixincludes to add a macro 
to wrap over mkdir on VxWorks.  A couple of possible ways to do this:

1.  Define a normal macro to posix-ify it, i.e. #define mkdir(a, b) 
((mkdir)(a)).  Since this would hide single-argument mkdir, it would 
probably be best to wrap it in #ifdef IN_GCC in order to avoid breaking 
existing vxWorks code.

2.  Make a variadic macro to allow for posix compatibility, i.e. #define 
mkdir(a, ...) ((mkdir)(a)).  I'm not sure if this works outside of C99 
mode - I know GCC supports it as an extension in C89 mode, but AFAIK the 
semantics are slightly different.  I'm also not sure about g++.  This 
does have the advantage though that it doesn't break any existing code.  
However, it does allow nonsensical 20 argument mkdir as well.

Either of these or the one in my previous email should work.  Which (or 
a different one entirely) would be preferred?

Thanks,

Robert

On Wed, 20 Jun 2012, rbmj wrote:
> There is an alternate solution- I could use fixincludes to add a macro to wrap
> over mkdir on VxWorks.  A couple of possible ways to do this:
>
> 1.  Define a normal macro to posix-ify it, i.e. #define mkdir(a, b)
> ((mkdir)(a)).  Since this would hide single-argument mkdir, it would probably
> be best to wrap it in #ifdef IN_GCC in order to avoid breaking existing
> vxWorks code.

Beware, if you go this route, I think you need to evaluate the
"mode" argument (b above), i.e. something like "#define mkdir(a,
b) ((b), (mkdir) (a))".

brgds, H-P

On 06/21/2012 09:40 PM, Hans-Peter Nilsson wrote:
> On Wed, 20 Jun 2012, rbmj wrote:
>> There is an alternate solution- I could use fixincludes to add a macro to wrap
>> over mkdir on VxWorks.  A couple of possible ways to do this:
>>
>> 1.  Define a normal macro to posix-ify it, i.e. #define mkdir(a, b)
>> ((mkdir)(a)).  Since this would hide single-argument mkdir, it would probably
>> be best to wrap it in #ifdef IN_GCC in order to avoid breaking existing
>> vxWorks code.
> Beware, if you go this route, I think you need to evaluate the
> "mode" argument (b above), i.e. something like "#define mkdir(a,
> b) ((b), (mkdir) (a))".
>
>
Yes, you're correct.  I think then that this makes the normal macro a 
better option than the variadic macro, even though the variadic is more 
compatible.  Wrapping the mkdir macro in IN_GCC should provide an 
adequate guard to prevent the macro from expanding in code that relies 
on the non-compliant signature.

I would ask who in the world puts expressions with side effects in as 
the mode argument and then relies on those side effects for something 
other than the (ignored) mode, but I know better :-P.

I think this is better than the previous solution as it doesn't require 
touching GCC itself per-se, and instead deals with header 
incompatibilities where they should be dealt with in fixincludes.  I'll 
write up a patch and put that with the other fixincludes patches I've 
submitted.

Thanks,

Robert