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[Bug target/50499] New: segmentation fault in gcc.dg/compat/struct-by-value-1 c_compat_x_tst.o-c_compat_y_tst.o with ppc -m64
- From: "vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 23 Sep 2011 21:57:36 +0000
- Subject: [Bug target/50499] New: segmentation fault in gcc.dg/compat/struct-by-value-1 c_compat_x_tst.o-c_compat_y_tst.o with ppc -m64
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50499
Bug #: 50499
Summary: segmentation fault in gcc.dg/compat/struct-by-value-1
c_compat_x_tst.o-c_compat_y_tst.o with ppc -m64
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: vries@gcc.gnu.org
The relevant C code from the testcase is this:
...
struct S50 {
unsigned char i[50];
}
void init50 (struct S50 *p, int i) {
int j;
for (j = 0; j < 50; j++)
p->i[j] = i + j;
}
void check50 (struct S50 x, int i) {
int j;
for (j = 0; j < 50; j++)
if (x.i[j] != i + j)
abort ();
}
struct S50 g1s50, g2s50, g3s50;
void checkg50 (void) {
check50 (g1s50, 64);
check50 (g2s50, 128);
check50 (g3s50, 192);
}
void testit50 (void) {
init50 (&g1s50, 64);
init50 (&g2s50, 128);
init50 (&g3s50, 192);
checkg50 ();
test50 (g1s50, g2s50, g3s50);
test2_50 (g1s50, g3s50);
}
...
In checkg50, the code for the second call to check50 looks like this:
...
addis 9,2,.LC152@toc@ha
mr 0,9
mr 11,0
ld 0,.LC152@toc@l(11)
mr 9,0
ld 3,0(9)
mr 11,0
ld 4,8(11)
mr 9,0
ld 5,16(9)
mr 11,0
ld 6,24(11)
mr 9,0
ld 7,32(9)
mr 11,0
ld 8,40(11)
mr 11,0
ld 9,48(11)
li 10,192
bl check50
...
I ran into a segmentation fault while executing 'ld 9,48(11)', the last load.
The LC152 data referenced is declared here:
...
.LC150:
.tc g1s50[TC],g1s50
.LC151:
.tc g2s50[TC],g2s50
.LC152:
.tc g3s50[TC],g3s50
.section ".text"
...
and defined here:
...
.comm g1s50,50,1
.comm g2s50,50,1
.comm g3s50,50,1
...
So g2s50 is only 50 chars big, but we try to read 52 chars from it. We happen
not to have access to the 2 extra chars, and this causes the segmentation
violation.