Bug#389225: Bad anulling of instruction in delay slot (gcc 4.1.1-13, sparc, building kernel)
Package: gcc-4.1
Version: 4.1.1-13
Severity: important
The compiler generates bad code when building the kernel using
gcc-4.1. I'm no expert at Sparc assembler syntax, but it seems
to be wrong.
This is from the assembler list file generated by gcc-4.1 when
compiling (-O2) /usr/src/linux/net/netfilter/xt_MARK.c:
.align 4
.type target_v1, #function
.proc 016
target_v1:
ldub [%o5+4], %g1
cmp %g1, 1
be,a .LL9
ld [%o0], %g3
; Here the load of %g3 is anulled, resulting in %g3 being used
; without being defined at label .LL9
bgeu .LL16
cmp %g1, 2
ld [%o5], %g2
.LL15:
ld [%o0], %g3
ld [%g3+128], %g1
.LL18:
.LL19:
cmp %g1, %g2
be .LL17
mov -1, %o0
st %g2, [%g3+128]
.LL17:
jmp %o7+8
nop
.LL16:
bne .LL15
mov 0, %g2
ld [%o0], %g3
ld [%o5], %g2
ld [%g3+128], %g1
b .LL18
or %g1, %g2, %g2
.LL9:
ld [%o5], %g2
ld [%g3+128], %g1
; Here we use %g3 without prior definition.
b .LL19
and %g1, %g2, %g2
.size target_v1, .-target_v1
This causes iptables to fail when adding targets that use the MARK
target.
Regards
/Daniel
Reply to: