Re: [PATCH v3] Add support for the readnever concept

Pedro Alves
2017-11-29T12:25:09Z

On 11/29/2017 01:21 AM, Sergio Durigan Junior wrote:
> Changes from v2:
>
> - Fixed a few nits pointed by Eli in the docs.
>
> - Implemented Pedro's suggestion and moved the logic of readnever out
> of the "*_build_psymtabs" and into the elf_symfile_read function.

See my comments here:
https://sourceware.org/ml/gdb-patches/2017-11/msg00766.html

> While implementing the code for the 'symbol-file' command, I noticed a
> bug in 'symbol_file_command': GDB adds the symbol file before
> finishing parsing all the options, which means that the position of an
> option in the command impacts whether it will be considered or not. I
> changed the code there in order to only add the symbol file after all
> options have been parsed.

Is this the same as:

https://sourceware.org/ml/gdb-patches/2017-11/msg00656.html

?

Sounds like something that would be better split off to
a precursor patch.

> +++ b/gdb/testsuite/gdb.base/readnever.c
> @@ -0,0 +1,43 @@
> +/* Copyright 2016-2017 Free Software Foundation, Inc.
> +
> + This program is free software; you can redistribute it and/or modify
> + it under the terms of the GNU General Public License as published by
> + the Free Software Foundation; either version 3 of the License, or
> + (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
> +
> +#include <stdio.h>

This include isn't necessary.

> +
> +static void
> +fun_three (int a, char b, void *c)
> +{
> + /* Do nothing. */
> +}
> +
> +static void
> +fun_two (unsigned int p, const char *y)
> +{
> + fun_three ((int) p, '1', (void *) y);
> +}
> +
> +static void
> +fun_one (int *x)
> +{
> + fun_two (10, (const char *) x);
> +}
> +
> +int
> +main (void)
> +{
> + int a = 10;
> +
> + fun_one (&a);
> + return 0;
> +}

> +# Test invalid combination of flags.
> +save_vars { GDBFLAGS } {
> + append GDBFLAGS " --readnever --readnow"
> + gdb_exit
> + gdb_spawn_ignore_error
> +
> + set test "test readnow and readnever at the same time"
> + gdb_test_multiple "" $test {
> + eof {
> + pass $test
> + }
> + }

I had suggested to match GDB's error output before the eof,
so I'm surprised to see only eof expected?

> +}
> +

> # Default gdb_spawn procedure.
>
> -proc default_gdb_spawn { } {
> +proc default_gdb_spawn { { ignore_error 0 } } {
> global use_gdb_stub
> global GDB
> global INTERNAL_GDBFLAGS GDBFLAGS
> @@ -1610,11 +1610,12 @@ proc default_gdb_spawn { } {
> }
> }
> set res [remote_spawn host "$GDB $INTERNAL_GDBFLAGS $GDBFLAGS [host_info gdb_opts]"]
> - if { $res < 0 || $res == "" } {
> - perror "Spawning $GDB failed."
> - return 1
> + if { !$ignore_error } {
> + if { $res < 0 || $res == "" } {
> + perror "Spawning $GDB failed."
> + return 1
> + }
> }

Hmm, I think I'm now confused on why this is needed in the first
place? GDB-the-executable should be starting successfully,
print some error output, and exit. What error do you see
here, exactly?

> -
> set gdb_spawn_id $res
> return 0
> }

Thanks,
Pedro Alves