gcc 4.9 build warnings (was: Re: next build: 2674 warnings 1 failures (next/next-20141022))

[Russell King - ARM Linux]

On Thu, Oct 23, 2014 at 10:31:07PM +0200, Arnd Bergmann wrote:
> On Thursday 23 October 2014 17:12:20 Russell King - ARM Linux wrote:
> > 
> > > I haven't found the code in gcc that performs the type check for
> > > printf, but I've found a comment about that code intentionally
> > > resolving the type (printing 'unsigned int') when the typedef
> > > does not match the expected type.
> > 
> > If I had a copy of the GCC 4.9 source locally, I'd dig into it too and
> > try to work out what's going on.  My gut feeling is that it's a bug in
> > GCC rather than something which the kernel is doing wrong.
> > 
> 
> I suspect it has something to do with the way that Olof's gcc is built,
> since it doesn't happen for me using the same kernel source and gcc-4.9.1
> or 4.10-prerelease.
> 
> The fact that it doesn't define __linux__ means that it must be configured
> in some other way than what I do or what I get from the distros.

Hmm, which may mean that it does expect "unsigned long" for size_t.

Olof, please can you try this fragment:

typedef __SIZE_TYPE__ gcc_size_t;
#include <stdio.h>
int main() { size_t size = 1; printf("%zu\n", size); return 0; }

with "arm-linux-gcc -E -o - test.c | grep size_t" and check what the
actual typedefs passed to the compiler proper are?  Thanks.

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