Use -ffreestanding?

From: Adrian Bunk
Date: Mon Nov 08 2004 - 18:39:41 EST


On Mon, Nov 08, 2004 at 08:01:30PM +0100, Andi Kleen wrote:
> On Mon, Nov 08, 2004 at 07:34:49PM +0100, Adrian Bunk wrote:
> > On Mon, Nov 08, 2004 at 06:51:20PM +0100, Andi Kleen wrote:
> > > On Mon, Nov 08, 2004 at 05:31:01PM +0100, Adrian Bunk wrote:
> > > > On Mon, Nov 08, 2004 at 05:19:35PM +0100, Andi Kleen wrote:
> > > > > > Rethinking it, I don't even understand the sprintf example in your
> > > > > > changelog entry - shouldn't an inclusion of kernel.h always get it
> > > > > > right?
> > > > >
> > > > > Newer gcc rewrites sprintf(buf,"%s",str) to strcpy(buf,str) transparently.
> > > >
> > > > Which gcc is "Newer"?
> > >
> > > I saw it with 3.3-hammer, which had additional optimizations in this
> > > area at some point. Note that 3.3-hammer is widely used. I don't
> > > know if 3.4 does it in the same way.
> >
> > Is this a -hammer specific problem?
>
> No, I just checked a 4.0 mainline gcc and it does it too.
>
> Note I saw it on x86-64, don't know if it occurs on i386 too.

OK, I see the difference:
After removing -fno-unit-at-a-time, I see this problem, too.

Why doesn't the kernel use -ffreestanding which should prevent all such
problems?

> -Andi

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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