Fix setting breakpoints or stepping on line 65535

  Hi,

this removes code that is present from the very first git revisison
7b4ac7e1ed2c4616bce56d1760807798be87ac9e from 1988.  It was in the
gdb/dbxread.c at the time (and makes more sense for dbx line info format
since line numbers are 16-bit entities in that debug format and debugging
files with more than 65535 lines would not work anyway) but moved from
there to gdb/buildsym.c which is used for dwarf line info as well, and
excluding an arbitrary line number does certainly not make sense nowadays.


Thanks
Bernd.
  

Ping...


On 11/24/19 12:54 PM, Bernd Edlinger wrote:
> Hi,
> 
> this removes code that is present from the very first git revisison
> 7b4ac7e1ed2c4616bce56d1760807798be87ac9e from 1988.  It was in the
> gdb/dbxread.c at the time (and makes more sense for dbx line info format
> since line numbers are 16-bit entities in that debug format and debugging
> files with more than 65535 lines would not work anyway) but moved from
> there to gdb/buildsym.c which is used for dwarf line info as well, and
> excluding an arbitrary line number does certainly not make sense nowadays.
> 
> 
> Thanks
> Bernd.
>
  

* Bernd Edlinger <bernd.edlinger@hotmail.de> [2019-11-24 11:54:23 +0000]:

> Hi,
> 
> this removes code that is present from the very first git revisison
> 7b4ac7e1ed2c4616bce56d1760807798be87ac9e from 1988.  It was in the
> gdb/dbxread.c at the time (and makes more sense for dbx line info format
> since line numbers are 16-bit entities in that debug format and debugging
> files with more than 65535 lines would not work anyway) but moved from
> there to gdb/buildsym.c which is used for dwarf line info as well, and
> excluding an arbitrary line number does certainly not make sense nowadays.
> 
> 
> Thanks
> Bernd.

> From f202ae765b72ad6d17600eb661993a63191309f7 Mon Sep 17 00:00:00 2001
> From: Bernd Edlinger <bernd.edlinger@hotmail.de>
> Date: Sat, 23 Nov 2019 07:37:26 +0100
> Subject: [PATCH 1/2] Fix setting breakpoints or stepping on line 65535
>

Bernd,

Thanks for looking into this, and especially thanks for adding a test!

Normally you should include the git commit message and ChangeLog along
with your patch submission so that these can be reviewed too. 'git
format-patch' and 'git send-email' can be useful for this, if you can
get them setup.

Given the age of the code you're removing I think this change sounds
reasonable.  I assume there's no test that covers why this code should
be there, so you see no regressions with this code removed?

I have a couple of minor issues with the test.  If you address those
and repost with commit message and ChangeLog this can be approved.

Thanks,
Andrew




> ---
>  gdb/buildsym.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/gdb/buildsym.c b/gdb/buildsym.c
> index 79f8305..6c14f3f 100644
> --- a/gdb/buildsym.c
> +++ b/gdb/buildsym.c
> @@ -670,12 +670,6 @@ buildsym_compunit::record_line (struct subfile *subfile, int line,
>  {
>    struct linetable_entry *e;
>  
> -  /* Ignore the dummy line number in libg.o */
> -  if (line == 0xffff)
> -    {
> -      return;
> -    }
> -
>    /* Make sure line vector exists and is big enough.  */
>    if (!subfile->line_vector)
>      {
> -- 
> 1.9.1
> 

> From 54a7631206a2cf54573fb4cc94474cb2f6f99245 Mon Sep 17 00:00:00 2001
> From: Bernd Edlinger <bernd.edlinger@hotmail.de>
> Date: Sun, 24 Nov 2019 09:37:22 +0100
> Subject: [PATCH 2/2] Add a test case for line 65535
> 
> ---
>  gdb/testsuite/gdb.base/line65535.c   | 19 +++++++++++++++++++
>  gdb/testsuite/gdb.base/line65535.exp | 26 ++++++++++++++++++++++++++
>  2 files changed, 45 insertions(+)
>  create mode 100644 gdb/testsuite/gdb.base/line65535.c
>  create mode 100644 gdb/testsuite/gdb.base/line65535.exp
> 
> diff --git a/gdb/testsuite/gdb.base/line65535.c b/gdb/testsuite/gdb.base/line65535.c
> new file mode 100644
> index 0000000..d80a294
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/line65535.c
> @@ -0,0 +1,19 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2019 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/>.  */
> +
> +#line 65535 "line65535.c"
> +int main() { return 0; }
> diff --git a/gdb/testsuite/gdb.base/line65535.exp b/gdb/testsuite/gdb.base/line65535.exp
> new file mode 100644
> index 0000000..2535ba5
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/line65535.exp
> @@ -0,0 +1,26 @@
> +# Copyright 2019 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/>.
> +

Normally we like to add a short description of what the test is doing
here - for new tests.  Many old ones don't have this thought.

> +standard_testfile
> +
> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
> +    return -1
> +}
> +
> +gdb_test "break $srcfile:65535" \
> +         ".*Breakpoint 1 at .*: file $srcfile, line 65535\\..*" \
> +	 "break at line 65535"
> +
> +return 0

I don't think this return is needed at the end of a test.

> -- 
> 1.9.1
>