Re: [PATCH] C undefined behavior fix

Tom Rini
2002-01-02T19:10:30Z

On Wed, Jan 02, 2002 at 01:03:25AM +0200, Momchil Velikov wrote:

> The GCC tries to replace the strcpy from a constant string source with
> a memcpy, since the length is know at compile time.

Okay, here's a summary of all of the options we have:
1) Change this particular strcpy to a memcpy
2) Add -ffreestanding to the CFLAGS of arch/ppc/kernel/prom.o (If this
optimization comes back on with this flag later on, it would be a
compiler bug, yes?)
3) Modify the RELOC() marco in such a way that GCC won't attempt to
optimize anything which touches it [1]. (Franz, again by Jakub)
4) Introduce a function to do the calculations [2]. (Corey Minyard)
5) 'Properly' set things up so that we don't need the RELOC() macros
(-mrelocatable or so?), and forget this mess altogether.

I think that if we're going to make sure that gcc-3.0.x works with 2.4.x
kernels, we should pick one of the first 4 initially. If this is only a
2.5.x matter, we should probably try and do #5 as a long-term goal, and
pick something else for now. But either way I do think it's time to
pick some solution. Comments?

--
Tom Rini (TR1265)
http://gate.crashing.org/~trini/

[1] http://lists.linuxppc.org/linuxppc-dev/200109/msg00155.html
[2] http://lists.linuxppc.org/linuxppc-dev/200112/msg00038.html