svn commit: r257691 - head/gnu/lib/libgcc

[Dimitry Andric]

On 06 Nov 2013, at 05:30, Bruce Evans <brde at optusnet.com.au> wrote:
> On Tue, 5 Nov 2013, Luigi Rizzo wrote:
>> On Tue, Nov 05, 2013 at 07:37:35AM +0000, Dimitry Andric wrote:
>>> Log:
>>>  Fix libgcc build with gcc after r257645, by using -Wno-static-in-inline
>>>  for clang only.
> This still just breaks the warning.  See my previous reply.  (For gcc,
> it is unclear if the missing warning is due too fewer warnings by
> default or if it is because gcc's default for plain inline is different
> from clang's so that the code is correct for gcc.).

First of all, gcc only emits this warning when using -pedantic, see
contrib/gcc/c-typeck.c, around line 2123.  However, our copy of gcc also
ships with a faulty C99 test in contrib/gcclibs/include/ansidecl.h,
which has (around line 176):

/* inline requires special treatment; it's in C99, and GCC >=2.7 supports                                                                                       
   it too, but it's not in C89.  */                                                                                                                             
#undef inline                                                                                                                                                   
#if __STDC_VERSION__ > 199901L                                                                                                                                  
/* it's a keyword */                                                                                                                                            
#else                                                                                                                                                           
# if GCC_VERSION >= 2007                                                                                                                                        
#  define inline __inline__   /* __inline__ prevents -pedantic warnings */                                                                                      
# else                                                                                                                                                          
#  define inline  /* nothing */                                                                                                                                 
# endif                                                                                                                                                         
#endif                                                                                                                                                          

Upstream gcc fixed this here:

http://gcc.gnu.org/viewcvs/gcc/trunk/include/ansidecl.h?r1=155654&r2=155653&pathrev=155654


>> I wonder if it is worthwhile adding to the default rules some
>> compiler-specific CFLAGS, say CFLAGS_CLANG and CFLAGS_GCC
>> 
>> (there is only a handful of cases now so maybe it is overkill,
>> and it harms readability; on the other hand, the Makefiles
>> already make a lot of assumptions on variable names)
> No, that would further simplify breaking warnings instead of fixing the
> bugs exposed by warnings.  The code should be portable so that it works
> with any compiler.  That is just not so easy for contrib'ed code unless
> the vendor made it portable.

I agree for this particular case, but there are other places in the tree
where we must pass either clang-specific or gcc-specific flags.
Introducing the variables Luigi suggested makes those Makefiles a little
less ugly, at least.


> I checked that libgcc is compiled by default with -std=gnu99.  This
> is just the default from bsd.sys.mk.  It is obviously wrong for libgcc,
> since the plain inlines in it require gnu89.

Yes, I agree.  This can be fixed in libgcc's Makefile, but unfortunately
clang will still emit the warning.


> gnu99 gives consistenly
> broken C99 semantic for both gcc and clang.  Only clang warned about
> this, and the warning has been broken.

Indeed, it always emits the warning, even for -std=gnu89, and even when
__inline__ is explicitly used.  This could probably be considered a bug,
but I think upstream has meant this as a general warning towards making
code C99-compliant.  Is it too hard to make a static variable
non-static? :)

-Dimitry

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