forked from Imagelibrary/binutils-gdb
17cf289784
When we connect to a remote target one of the first things GDB does is
establish a frame id. If an error is thrown while building this frame
id then GDB will disconnect from the target.
This can mean that, if the user is attempting to connect to a target
that doesn't yet have a program loaded, or the program the user is
going to load onto the target doesn't match what is already loaded, or
the target is just in some undefined state, then the very first
request for a frame id can fail (for example, by trying to load from
an invalid memory address), and GDB will disconnect. It is then
impossible for the user to connect to the target and load a new
program at all.
An example of such a session might look like this:
Reading symbols from ./gdb/testsuite/outputs/gdb.arch/riscv-reg-aliases/riscv-reg-aliases...
(gdb) target remote :37191
Remote debugging using :37191
0x0000000000000100 in ?? ()
Cannot access memory at address 0x0
(gdb) load
You can't do that when your target is `exec'
(gdb) info frame
/path/to/gdb/gdb/thread.c:93: internal-error: thread_info* inferior_thread(): Assertion `tp' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
The solution is to handle errors in riscv_frame_this_id, and leave the
this_id variable with its default value, which is the predefined
'outermost' frame.
With this fix in place, connecting to the same target now looks like
this:
(gdb) target remote :37191
Remote debugging using :37191
0x0000000000000100 in ?? ()
(gdb) info frame
Stack level 0, frame at 0x0:
pc = 0x100; saved pc = <not saved>
Outermost frame: outermost
Arglist at unknown address.
Locals at unknown address, Previous frame's sp in sp
gdb/ChangeLog:
* riscv-tdep.c (riscv_insn::decode): Update header comment.
(riscv_frame_this_id): Catch errors thrown while building the
frame cache, leave the frame id as the default, which is the outer
frame id.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.