Hy,
I have a problem using watchpoints with gdb,
probably a problem with internal blocks (sorry for the guess :-)
I'm using the C programm:
--- C program ---- (gdb2.c)
int procedure()
{
int faults = 0;
{
int a = 3;
int b = 14;
if (a != b) faults++;
}
return faults;
}
int main()
{
procedure();
exit(0);
}
---- end c program ---
compiled with gcc:
---- shell:
< rif22: ~/tmp > gcc -v
Reading specs from /pub/gcc/2.95.2/lib/gcc-lib/sparc-sun-solaris2.6/2.95.2/specs
gcc version 2.95.2 19991024 (release)
< rif22: ~/tmp > gcc -Wall -g gdb2.c -o gdbtest
---- end
then I make the following gdb-session: for getting an internal error
--- shell:
< rif22: ~/tmp > gdb -v
GDB 4.16 (sparc-sun-solaris2.6), Copyright 1996 Free Software Foundation, Inc.
< rif22: ~/tmp > gdb gdbtest
GDB is free software and you are welcome to distribute copies of it
under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.16 (sparc-sun-solaris2.6), Copyright 1996 Free Software Foundation, Inc...
(gdb) break procedure
Breakpoint 1 at 0x10950: file gdb2.c, line 3.
(gdb) r
Starting program: /home/tholenst/tmp/gdbtest
Breakpoint 1, procedure () at gdb2.c:3
3 int faults = 0;
(gdb) watch faults
Watchpoint 2: faults
(gdb) c
Continuing.
Watchpoint 2: faults
Old value = 0
New value = 1
procedure () at gdb2.c:10
10 return faults;
(gdb) c
Continuing.
Watchpoint 2 deleted because the program has left the block in
which its expression is valid.
gdb internal error: Memory corruption
Quit
< rif22: ~/tmp >
------ end shell
Some more information:
--- shell:
< rif22: ~/tmp > uname -a
SunOS rif22 5.6 Generic_105181-19 sun4u sparc SUNW,Ultra-5_10
--- end shell
gcc -Wall -g gdb2.c -S gives:
--- assembler output:
.file "gdb2.c"
.stabs "/home/tholenst/tmp/",100,0,0,.LLtext0
.stabs "gdb2.c",100,0,0,.LLtext0
.section ".text"
.LLtext0:
.stabs "gcc2_compiled.", 0x3c, 0, 0, 0
.stabs "int:t(0,1)=r(0,1);0020000000000;0017777777777;",128,0,0,0
.stabs "char:t(0,2)=r(0,2);0;127;",128,0,0,0
.stabs "long int:t(0,3)=r(0,1);0020000000000;0017777777777;",128,0,0,0
.stabs "unsigned int:t(0,4)=r(0,1);0000000000000;0037777777777;",128,0,0,0
.stabs "long unsigned int:t(0,5)=r(0,1);0000000000000;0037777777777;",128,0,0,0
.stabs "long long
int:t(0,6)=r(0,1);01000000000000000000000;0777777777777777777777;",128,0,0,0
.stabs "long long unsigned
int:t(0,7)=r(0,1);0000000000000;01777777777777777777777;",128,0,0,0
.stabs "short int:t(0,8)=r(0,8);-32768;32767;",128,0,0,0
.stabs "short unsigned int:t(0,9)=r(0,9);0;65535;",128,0,0,0
.stabs "signed char:t(0,10)=r(0,10);-128;127;",128,0,0,0
.stabs "unsigned char:t(0,11)=r(0,11);0;255;",128,0,0,0
.stabs "float:t(0,12)=r(0,1);4;0;",128,0,0,0
.stabs "double:t(0,13)=r(0,1);8;0;",128,0,0,0
.stabs "long double:t(0,14)=r(0,1);16;0;",128,0,0,0
.stabs "complex int:t(0,15)=s8real:(0,1),0,32;imag:(0,1),32,32;;",128,0,0,0
.stabs "complex float:t(0,16)=r(0,16);4;0;",128,0,0,0
.stabs "complex double:t(0,17)=r(0,17);8;0;",128,0,0,0
.stabs "complex long double:t(0,18)=r(0,18);16;0;",128,0,0,0
.stabs "void:t(0,19)=(0,19)",128,0,0,0
.align 4
.stabs "procedure:F(0,1)",36,0,2,procedure
.global procedure
.type procedure,#function
.proc 04
procedure:
.stabn 68,0,2,.LLM1-procedure
.LLM1:
!#PROLOGUE# 0
save %sp, -128, %sp
!#PROLOGUE# 1
.stabn 68,0,3,.LLM2-procedure
.LLM2:
.LLBB2:
st %g0, [%fp-20]
.stabn 68,0,6,.LLM3-procedure
.LLM3:
.LLBB3:
mov 3, %o0
st %o0, [%fp-24]
.stabn 68,0,7,.LLM4-procedure
.LLM4:
mov 14, %o0
st %o0, [%fp-28]
.stabn 68,0,8,.LLM5-procedure
.LLM5:
ld [%fp-24], %o0
ld [%fp-28], %o1
cmp %o0, %o1
be .LL3
nop
ld [%fp-20], %o0
add %o0, 1, %o1
st %o1, [%fp-20]
.LL3:
.stabn 68,0,9,.LLM6-procedure
.LLM6:
.LLBE3:
.stabn 68,0,10,.LLM7-procedure
.LLM7:
ld [%fp-20], %o0
mov %o0, %i0
b .LL2
nop
.stabn 68,0,12,.LLM8-procedure
.LLM8:
.LLBE2:
.stabn 68,0,12,.LLM9-procedure
.LLM9:
.LL2:
ret
restore
.LLfe1:
.size procedure,.LLfe1-procedure
.stabs "faults:(0,1)",128,0,3,-20
.stabn 192,0,0,.LLBB2-procedure
.stabs "a:(0,1)",128,0,6,-24
.stabs "b:(0,1)",128,0,7,-28
.stabn 192,0,0,.LLBB3-procedure
.stabn 224,0,0,.LLBE3-procedure
.stabn 224,0,0,.LLBE2-procedure
.LLscope0:
.stabs "",36,0,0,.LLscope0-procedure
.align 4
.stabs "main:F(0,1)",36,0,15,main
.global main
.type main,#function
.proc 04
main:
.stabn 68,0,15,.LLM10-main
.LLM10:
!#PROLOGUE# 0
save %sp, -112, %sp
!#PROLOGUE# 1
.stabn 68,0,16,.LLM11-main
.LLM11:
call procedure, 0
nop
.stabn 68,0,17,.LLM12-main
.LLM12:
mov 0, %o0
call exit, 0
nop
.stabn 68,0,18,.LLM13-main
.LLM13:
.LL4:
ret
restore
.LLfe2:
.size main,.LLfe2-main
.LLscope1:
.stabs "",36,0,0,.LLscope1-main
.text
.stabs "",100,0,0,Letext
Letext:
.ident "GCC: (GNU) 2.95.2 19991024 (release)"
--- end assembler output
Preprocessing is trivial:
--- shell:
< rif22: ~/tmp > gcc -Wall -g gdb2.c -E
# 1 "gdb2.c"
int procedure()
{
int faults = 0;
{
int a = 3;
int b = 14;
if (a != b) faults++;
}
return faults;
}
int main()
{
procedure();
exit(0);
}
--- end shell
Greetings
Thomas
