Hi,
This problem occurs on native (in my case i686-pc-linux(-gnu)) on both
the 2000-05-19 release, as well as the latest CVS sources. What happens
is that when I set a breakpoint at a function, call it from gdb, and
force a return, gdb is thoroughly confused upon return. Allow me to
illustrate what happens (using the funcargs test case from gdb.base):
(gdb) b add
Breakpoint 2 at 0x8048443: file
../../../src/gdb/testsuite/gdb.base/callfuncs.c, line 58.
(gdb) call add(4,5)
Breakpoint 2, add (a=4, b=5)
at ../../../src/gdb/testsuite/gdb.base/callfuncs.c:58
58 return (a + b);
The program being debugged stopped while in a function called from GDB.
When the function (add) is done executing, GDB will silently
stop (instead of continuing to evaluate the expression containing
the function call).
(gdb) return
Make add return now? (y or n) y
#0 <function called from gdb>
(gdb) bt
#0 <function called from gdb>
#1 main () at ../../../src/gdb/testsuite/gdb.base/callfuncs.c:185
#2 0x4004ca42 in __libc_start_main () from /lib/libc.so.6
(gdb) n
warning: Cannot insert breakpoint 0:
Cannot access memory at address 0x4
I'm merely using native gdb as a reference for my gdb port (which is for
cross-debugging), and I'm not very familiar with the i386 registers.
What happens with my gdb port is that the dummy pc used to recognize
that we are in a call dummy is written to the pc when continuing from
the breakpoint. Regular function calls from within gdb, when there is no
breakpoint in the called function, works fine.
I'm probably asking for trouble by forcing a return in that situation,
but I don't think the situation at hand is unimaginable.
Orjan Friberg
Axis Communications AB
E-mail: [EMAIL PROTECTED]
Phone: +46 46 272 17 68
