[TESTING]: one more boot2 shrinking patch
jhb at freebsd.org
Thu Mar 10 15:23:16 UTC 2011
On Wednesday, March 09, 2011 6:24:36 pm Dimitry Andric wrote:
> On 2011-03-09 14:23, John Baldwin wrote:
> >> gcc nor clang emits any code to initialize static type foo = 0;
> >> because it's expected that BSS is zeroed, which is not the case
> >> in boot2 so we have to initialize that explicitly
> > It used to be that if you explicitly initialized a variable to 0, it was
> > initialized to 0 in .data, but now gcc and clang recognize it is set to 0 and
> > move it to .bss. There appears to be no way to turn this feature off,
> Yes, there is; both gcc and clang have this option to turn it off:
> If the target supports a BSS section, GCC by default puts variables
> that are initialized to zero into BSS. This can save space in the
> resulting code.
> This option turns off this behavior because some programs
> explicitly rely on variables going to the data section. E.g., so
> that the resulting executable can find the beginning of that
> section and/or make assumptions based on that.
> The default is -fzero-initialized-in-bss.
Hah, that is better then. Thanks! I should have searched about this more
myself. :( Roman, can you try reverting the kname changes and adding this
to CFLAGS instead for both compilers?
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