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[Bug backtrace/11838] New: Unwind should undefine caller-saved registers
- From: "jan dot kratochvil at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: gdb-prs at sourceware dot org
- Date: 24 Jul 2010 16:40:40 -0000
- Subject: [Bug backtrace/11838] New: Unwind should undefine caller-saved registers
- Reply-to: sourceware-bugzilla at sourceware dot org
Formerly GDB tried to show what it can. Nowadays with GCC VTA it should hide
values which may be / are corrupted as it may be misleading.
DWARF2_FRAME_REG_UNSPECIFIED is currently equal to DWARF2_FRAME_REG_SAME_VALUE.
DWARF2_FRAME_REG_UNSPECIFIED should respect target arch caller-saved vs.
callee-saved registers map and mark caller-saved registers as unknown (which is
currently only possible by DWARF2_FRAME_REG_UNDEFINED and thus
frame_unwind_got_optimized which is not completely right but it would work).
FAIL all these:
gcc (GCC) 4.6.0 20100724 (experimental)
gcc (GCC) 4.4.5 20100724 (prerelease)
gcc-4.4.4-10.fc13.x86_64
GNU gdb (GDB) 7.2.50.20100724-cvs
#0 breakat (q=0) at 1.c:7
#1 0x000000000040053b in f (a1=<value optimized out>, a2=2, a3=3, a4=4, a5=5,
a6=6, a7=7) at 2.c:6
#2 0x00000000004004fc in g (x=0) at 1.c:14
^^^ x=10 here, it should be <value optimized out>
#3 0x000000000040051e in main () at 2.c:14
==> 1.c <==
#include <stdlib.h>
extern __attribute__((noreturn)) void f (long a1, long a2, long a3, long a4,
long a5, long a6, long a7);
__attribute__((noreturn)) void
breakat (long q)
{
exit (0);
}
__attribute__((noinline)) void
g (long x)
{
f (x, 2, 3, 4, 5, 6, 7);
}
==> 2.c <==
extern __attribute__((noreturn)) void breakat (long q);
__attribute__((noreturn)) void
f (long a1, long a2, long a3, long a4, long a5, long a6, long a7)
{
breakat (0);
}
extern __attribute__((noinline)) void g (long x);
int
main (void)
{
g (10);
return 0;
}
--
Summary: Unwind should undefine caller-saved registers
Product: gdb
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: backtrace
AssignedTo: unassigned at sourceware dot org
ReportedBy: jan dot kratochvil at redhat dot com
CC: gdb-prs at sourceware dot org
GCC target triplet: x86_64-fedora13-linux-gnu
http://sourceware.org/bugzilla/show_bug.cgi?id=11838
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