--- Comment #35 from phmagic at mail dot ru 2010-06-10 19:08 ---
Hello,
I just upgraded to gcc-4.4.3 (from Gentoo distribution) and recompiled the
whole system (on x86). Then I had to discover the (as it turned to be,
infamous) mozilla-firefox + zlib bug. I reported it to the distribution here:
http://bugs.gentoo.org/show_bug.cgi?id=323431
As I learned later, everybody accounts for incoming misaligned stack to be the
cause of the crashes. But what I see:
inflate_table:
.LFB45:
.file 1 "inftrees.c"
.loc 1 39 0
.LVL0:
pushl %ebp ; stack misaligned to -4
.LCFI0:
.loc 1 108 0
pxor%xmm0, %xmm0
.loc 1 39 0
movl%esp, %ebp ; $ebp % 16 = 4
.LCFI1:
pushl %edi
.LCFI2:
pushl %esi
.LCFI3:
pushl %ebx
.LCFI4:
call.L101
.L101:
popl%ebx
addl$_GLOBAL_OFFSET_TABLE_+[.-.L101], %ebx
subl$188, %esp
.LCFI5:
.loc 1 108 0
movdqa %xmm0, -56(%ebp) ; -56-4=60, 60%16=4
;
Even if the stack were 16 bytes aligned on the entry, the instruction in the
last line would attempt an unaligned access and thus would fault. Please
correct me, if I miscounted.
My concern is: even with ABI which guarantees 16-byte aligned incoming stacks,
gcc generates code which would segfault.
--
phmagic at mail dot ru changed:
What|Removed |Added
CC| |phmagic at mail dot ru
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41156
