XEN 3.0.1 vsprintf.c - strange macro expansion

XEN 3.0.1 vsprintf.c - strange macro expansion

[Armand Puccetti]

When preprocessing the file vsprintf.c, macro 'va_arg' gets expanded 
into '__builtin_va_arg', which is not XEN code.

For instance, at line 317 of that file,

    field_width = va_arg(args,int);

becomes

    field_width = __builtin_va_arg(args,int);

using the preprocessing command below.

    cpp -C -E -nostdinc -iwithprefix include -I.../xen-3.0.1/xen/include 
-I.../xen-3.0.1/xen/include/asm-x86/mach-generic 
-I.../xen-3.0.1/xen/include/asm-x86/mach-default -DNDEBUG -D__i386__ 
vsprintf.c

The def inition of macro va_arg is located in file acenv.h:298, but has 
little to do with this result.
Settings: Compiler: gcc 4.0.2, OS: Ubuntu Linux kernel 2.6.12.10

What might be the reason of this behavior? A bug in gcc?

Re: XEN 3.0.1 vsprintf.c - strange macro expansion

[Anthony Liguori]

Armand Puccetti wrote:
> When preprocessing the file vsprintf.c, macro 'va_arg' gets expanded 
> into '__builtin_va_arg', which is not XEN code.
>
> For instance, at line 317 of that file,
>
>    field_width = va_arg(args,int);
>
> becomes
>
>    field_width = __builtin_va_arg(args,int);
>
> using the preprocessing command below.
>
>    cpp -C -E -nostdinc -iwithprefix include 
> -I.../xen-3.0.1/xen/include 
> -I.../xen-3.0.1/xen/include/asm-x86/mach-generic 
> -I.../xen-3.0.1/xen/include/asm-x86/mach-default -DNDEBUG -D__i386__ 
> vsprintf.c
>
> The def inition of macro va_arg is located in file acenv.h:298, but 
> has little to do with this result.
> Settings: Compiler: gcc 4.0.2, OS: Ubuntu Linux kernel 2.6.12.10

I don't know what acenv.h but AFAIK we aren't using it's va_arg() 
definition.  We include stdarg.h and I assume we build with libgcc.

Regards,

Anthony Liguori

> What might be the reason of this behavior? A bug in gcc?
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel