Re: [Xen-devel] [PATCH] xen: Don't use -nostdinc flags with CLANG

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

On 02/13/2014 11:24 AM, Tim Deegan wrote:
> George: ping.
>
> At 15:33 +0100 on 11 Feb (1392129226), Tim Deegan wrote:
> > At 14:24 +0000 on 11 Feb (1392125052), Julien Grall wrote:
> > > If it's possible I'd like this patch goes in Xen 4.4 to fix build with
> > > official version of clang (until 3.4).
> > >
> > > Clang 3.5 is still under development, so I don't think it's important to
> > > have support for it in Xen 4.4.
> > Fair enough.  In that case it needs a release ack from George.  It:
> >   - fixes a compile issue on some version s of clang;
> >   - might cause a regression with other compilers, but the regression
> >     is likely to be obvious (i.e. a compile-time failure).
So the main risk would be if stgarg.h contained something like the 
"__GNUC_PREREQ__(4, 5)" #ifdef-ery that we missed.  Without this patch, 
we know it doesn't compile on the latest version of clang.  I think 
that's probably worse than the risk of potentially not compiling on some 
compiler that doesn't end up being tested before the release:
Release-acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>


> > And it needs an ack from Keir, for changing common code.
> >
> > v2 is below, removing "-iwithprefix".  I've kept your tested-by; hope
> > that's OK.
> >
> > Cheers,
> >
> > Tim.
> >
> > commit 1d62fcb9ad8d2b409ac2cf0e8a3824e19ca3313f
> > Author: Tim Deegan <tim@xxxxxxx>
> > Date:   Tue Feb 11 12:44:09 2014 +0000
> >
> >      xen: stop trying to use the system <stdarg.h> and <stdbool.h>
> >      
> >      We already have our own versions of the stdarg/stdbool definitions, for
> >      systems where those headers are installed in /usr/include.
> >      
> >      On linux, they're typically installed in compiler-specific paths, but
> >      finding them has proved unreliable.  Drop that and use our own versions
> >      everywhere.
> >      
> >      Signed-off-by: Tim Deegan <tim@xxxxxxx>
> >      Tested-by: Julien Grall <julien.grall@xxxxxxxxxx>
> >
> > diff --git a/xen/Rules.mk b/xen/Rules.mk
> > index df1428f..3a6cec5 100644
> > --- a/xen/Rules.mk
> > +++ b/xen/Rules.mk
> > @@ -44,10 +44,7 @@ ALL_OBJS-$(x86)          += $(BASEDIR)/crypto/built_in.o
> >   CFLAGS += -fno-builtin -fno-common
> >   CFLAGS += -Werror -Wredundant-decls -Wno-pointer-arith
> >   CFLAGS += -pipe -g -D__XEN__ -include $(BASEDIR)/include/xen/config.h
> > -# Solaris puts stdarg.h &c in the system include directory.
> > -ifneq ($(XEN_OS),SunOS)
> > -CFLAGS += -nostdinc -iwithprefix include
> > -endif
> > +CFLAGS += -nostdinc
> >   
> >   CFLAGS-$(XSM_ENABLE)    += -DXSM_ENABLE
> >   CFLAGS-$(FLASK_ENABLE)  += -DFLASK_ENABLE -DXSM_MAGIC=0xf97cff8c
> > diff --git a/xen/include/xen/stdarg.h b/xen/include/xen/stdarg.h
> > index d1b2540..0283f06 100644
> > --- a/xen/include/xen/stdarg.h
> > +++ b/xen/include/xen/stdarg.h
> > @@ -1,23 +1,21 @@
> >   #ifndef __XEN_STDARG_H__
> >   #define __XEN_STDARG_H__
> >   
> > -#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
> > -   typedef __builtin_va_list va_list;
> > -#  ifdef __GNUC__
> > -#    define __GNUC_PREREQ__(x, y)                                       \
> > -        ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
> > -         (__GNUC__ > (x)))
> > -#  else
> > -#    define __GNUC_PREREQ__(x, y)   0
> > -#  endif
> > -#  if !__GNUC_PREREQ__(4, 5)
> > -#    define __builtin_va_start(ap, last)    __builtin_stdarg_start((ap), 
> > (last))
> > -#  endif
> > -#  define va_start(ap, last)    __builtin_va_start((ap), (last))
> > -#  define va_end(ap)            __builtin_va_end(ap)
> > -#  define va_arg                __builtin_va_arg
> > +#ifdef __GNUC__
> > +#  define __GNUC_PREREQ__(x, y)                                       \
> > +      ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
> > +       (__GNUC__ > (x)))
> >   #else
> > -#  include <stdarg.h>
> > +#  define __GNUC_PREREQ__(x, y)   0
> >   #endif
> >   
> > +#if !__GNUC_PREREQ__(4, 5)
> > +#  define __builtin_va_start(ap, last)    __builtin_stdarg_start((ap), (last))
> > +#endif
> > +
> > +typedef __builtin_va_list va_list;
> > +#define va_start(ap, last)    __builtin_va_start((ap), (last))
> > +#define va_end(ap)            __builtin_va_end(ap)
> > +#define va_arg                __builtin_va_arg
> > +
> >   #endif /* __XEN_STDARG_H__ */
> > diff --git a/xen/include/xen/stdbool.h b/xen/include/xen/stdbool.h
> > index f0faedf..b0947a6 100644
> > --- a/xen/include/xen/stdbool.h
> > +++ b/xen/include/xen/stdbool.h
> > @@ -1,13 +1,9 @@
> >   #ifndef __XEN_STDBOOL_H__
> >   #define __XEN_STDBOOL_H__
> >   
> > -#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
> > -#  define bool _Bool
> > -#  define true 1
> > -#  define false 0
> > -#  define __bool_true_false_are_defined   1
> > -#else
> > -#  include <stdbool.h>
> > -#endif
> > +#define bool _Bool
> > +#define true 1
> > +#define false 0
> > +#define __bool_true_false_are_defined   1
> >   
> >   #endif /* __XEN_STDBOOL_H__ */
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

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