[PATCH 1/1] gdb, infcmd: Support jump command with same line in multiple object files.

Bruno Larsen blarsen@redhat.com
Thu Apr 13 14:32:39 GMT 2023


On 08/03/2023 14:26, Matti Puputti via Gdb-patches wrote:
> If the jump target is found in multiple object files, select the one in
> the current object file.

Hi, thanks for working on this. I think this is a reasonable change, but 
I have some comments.

First, I think your cover letter description makes for a better commit 
message than the one you provided here. Also, you say "object file" but 
use symtab in the code. Each symtab is related to a compilation unit, 
and an objfile can have multiple compilation units. I think bit more 
precise in the language would be nice :)

> ---
>   gdb/infcmd.c                       | 14 ++++++-
>   gdb/testsuite/gdb.base/jump2.c     | 29 +++++++++++++++
>   gdb/testsuite/gdb.base/jump2.exp   | 59 ++++++++++++++++++++++++++++++
>   gdb/testsuite/gdb.base/jump2.h     | 30 +++++++++++++++
>   gdb/testsuite/gdb.base/jump2_foo.c | 24 ++++++++++++
>   5 files changed, 155 insertions(+), 1 deletion(-)
>   create mode 100755 gdb/testsuite/gdb.base/jump2.c
>   create mode 100755 gdb/testsuite/gdb.base/jump2.exp
>   create mode 100755 gdb/testsuite/gdb.base/jump2.h
>   create mode 100755 gdb/testsuite/gdb.base/jump2_foo.c
>
> diff --git a/gdb/infcmd.c b/gdb/infcmd.c
> index c369b795757..1b91562f137 100644
> --- a/gdb/infcmd.c
> +++ b/gdb/infcmd.c
> @@ -1080,7 +1080,19 @@ jump_command (const char *arg, int from_tty)
>     std::vector<symtab_and_line> sals
>       = decode_line_with_last_displayed (arg, DECODE_LINE_FUNFIRSTLINE);
>     if (sals.size () != 1)
> -    error (_("Unreasonable jump request"));
> +    {
> +      /* If multiple sal-objects were found, try dropping those that aren't
> +	 from the current objectfile.  */
> +      sals.erase (std::remove_if (sals.begin (), sals.end (),
> +		  [] (symtab_and_line &sal)
> +		    {
> +		      struct symtab_and_line cursal
> +			  = get_current_source_symtab_and_line ();
> +		      return sal.symtab != cursal.symtab;
> +		    }), sals.end ());
> +      if (sals.size () != 1)
> +	error (_("Unreasonable jump request"));
> +    }
>   
>     symtab_and_line &sal = sals[0];
>   
> diff --git a/gdb/testsuite/gdb.base/jump2.c b/gdb/testsuite/gdb.base/jump2.c
> new file mode 100755
> index 00000000000..468838a9d1a
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/jump2.c
I think that a more descriptive name, like jump_multiple_objfiles, would 
be better.
> @@ -0,0 +1,29 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2021-2023 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 "jump2.h"
> +
> +extern int foo (int n);
> +
> +
> +int main ()

the coding guidelines ask that this be:

int

main ()

> +{
> +  int n = foo (1);
> +  bar (n);
> +
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/jump2.exp b/gdb/testsuite/gdb.base/jump2.exp
> new file mode 100755
> index 00000000000..f6bc29dfe1c
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/jump2.exp
> @@ -0,0 +1,59 @@
> +#   Copyright 2021-2023 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/>.  */
> +#
> +# Tests GDBs support for jump, when the source line is in multiple
> +# object files.
> +
> +
> +standard_testfile .c
> +set srcfile2 jump2_foo.c
> +set srcfile3 jump2.h
> +
> +
> +if { [prepare_for_testing "failed to prepare" $testfile \
> +      [list ${srcfile} ${srcfile2}]] } {
> +    return -1
> +}
> +
> +if { ![runto_main] } {
> +    perror "couldn't run to breakpoint"
> +    return -1
> +}
> +
> +
> +set bar_first_line [gdb_get_line_number "bar-first-line" ${srcfile3}]
> +set bar_middle_line [gdb_get_line_number "bar-middle-line" ${srcfile3}]
> +set bar_last_line [gdb_get_line_number "bar-last-line" ${srcfile3}]
> +
> +
> +# Set breakpoints in the function bar.  Executable has two object files,
> +# and both have a copy of the same source lines.  Therefore breakpoints
> +# will have two locations.
> +gdb_test "break ${srcfile3}:${bar_first_line}" \
> +    "Breakpoint.* at .*${srcfile3}:${bar_first_line}\\\. \\\(2 locations\\\)"
> +gdb_test "break ${srcfile3}:${bar_last_line}" \
> +    "Breakpoint.* at .*${srcfile3}:${bar_last_line}\\\. \\\(2 locations\\\)"

You can simplify this by using gdb_breakpoint, which is also more 
resilient that manually setting the breakpoint message.

I also tested locally and seen no regressions, but I'd like to see my 
comments changed before giving my tag

-- 
Cheers,
Bruno

> +
> +# Run to the breakpoint in bar.
> +gdb_continue_to_breakpoint "bar_first_line" \
> +    ".*${srcfile3}:${bar_first_line}.*"
> +
> +# Jump within the function.  Debugger shall be able to jump, even if the
> +# target line is in two different object files.  After jump, we will hit
> +# the breakpoint at the last line of bar.
> +gdb_test "jump ${bar_middle_line}"  [multi_line \
> +    "Continuing at ($hex).*" \
> +    "Breakpoint ${decimal}.* at .*${srcfile3}:${bar_last_line}.*"] \
> +    "Jump within the objectfile"
> diff --git a/gdb/testsuite/gdb.base/jump2.h b/gdb/testsuite/gdb.base/jump2.h
> new file mode 100755
> index 00000000000..5e3849cb3cb
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/jump2.h
> @@ -0,0 +1,30 @@
> +/* Copyright (C) 2021-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   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/>.  */
> +
> +#ifndef JUMP2_H
> +#define JUMP2_H
> +
> +static int
> +bar (int n)
> +{
> +  int retval = n;
> +  retval += 1;      /* bar-first-line */
> +  retval *= -1;     /* bar-middle-line */
> +  return retval;    /* bar-last-line */
> +}
> +
> +#endif /* JUMP2_H */
> diff --git a/gdb/testsuite/gdb.base/jump2_foo.c b/gdb/testsuite/gdb.base/jump2_foo.c
> new file mode 100755
> index 00000000000..667f2398551
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/jump2_foo.c
> @@ -0,0 +1,24 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2021-2023 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 "jump2.h"
> +
> +int
> +foo (int n)
> +{
> +  return bar (n);
> +}



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