From: Andrew Burgess <aburgess@redhat.com>
To: Simon Marchi <simark@simark.ca>, gdb-patches@sourceware.org
Cc: Bruno Larsen <blarsen@redhat.com>
Subject: Re: [PATCHv3] gdb/c++: fix handling of breakpoints on @plt symbols
Date: Sun, 12 Feb 2023 06:22:45 +0000 [thread overview]
Message-ID: <875yc7v1vu.fsf@redhat.com> (raw)
In-Reply-To: <c9315691-00e3-b84f-206e-891876db8fb7@simark.ca>
Simon Marchi <simark@simark.ca> writes:
>> diff --git a/gdb/testsuite/gdb.cp/breakpoint-shlib-func-lib.cc b/gdb/testsuite/gdb.cp/breakpoint-shlib-func-lib.cc
>> new file mode 100644
>> index 00000000000..7219f7c5a23
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.cp/breakpoint-shlib-func-lib.cc
>> @@ -0,0 +1,21 @@
>> +/* Copyright 2022-2023 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/>. */
>> +
>> +extern int foo ();
>
> I don't think this extern declaration is needed.
>
>> +# The breakpoint should now be showing in `foo` for real.
>> +gdb_test "info breakpoints" \
>> + "\r\n$decimal\\s+\[^\r\n\]+ in foo\\(\\) at \[^\r\n\]+\r\n.*" \
>> + "check breakpoints after starting the inferior"
>> +
>> +# Now we can delete the breakpoints.
>> +delete_breakpoints
>> +
>> +# And recreate the foo breakpoint, we should only get one location,
>> +# the actual location.
>> +gdb_test "break foo" "Breakpoint $decimal at \[^\r\n\]+" \
>> + "recreate foo breakpoint"
>> +
>> +# Check the breakpoint was recreated correctly.
>> +gdb_test "info breakpoints" \
>> + "\r\n$decimal\\s+\[^\r\n\]+ in foo\\(\\) at \[^\r\n\]+" \
>> + "check breakpoints after recreation"
>
> For completeness, you could maybe resume and confirm you are stopped at
> foo (and not foo@plt).
>
> Otherwise, it all LGTM:
I removed the 'extern' and added an extra check that we hit the expected
breakpoint, then pushed this patch.
Thanks,
Andrew
>
> Approved-By: Simon Marchi <simon.marchi@efficios.com>
>
>> diff --git a/gdb/utils.c b/gdb/utils.c
>> index 95adbe58e4a..76c0df36a80 100644
>> --- a/gdb/utils.c
>> +++ b/gdb/utils.c
>> @@ -2402,7 +2402,31 @@ strncmp_iw_with_mode (const char *string1, const char *string2,
>> return 0;
>> }
>> else
>> - return (*string1 != '\0' && *string1 != '(');
>> + {
>> + if (*string1 == '(')
>> + {
>> + int p_count = 0;
>> +
>> + do
>> + {
>> + if (*string1 == '(')
>> + ++p_count;
>> + else if (*string1 == ')')
>> + --p_count;
>> + ++string1;
>> + }
>> + while (*string1 != '\0' && p_count > 0);
>> +
>> + /* There maybe things like 'const' after the parameters,
>> + which we do want to ignore. However, if there's an '@'
>> + then this likely indicates something like '@plt' which we
>> + should not ignore. */
>> + return *string1 == '@';
>> + }
>> +
>> + return *string1 == '\0' ? 0 : 1;
>> + }
>
> Not really relevant for your patch but... just chatting. I don't know
> if it would be really inefficient, but reading this function, I dream of
> some util function that would parse a demangled C++ function symbol into
> some structured type (listing the namespaces, name, abi tags,
> parameters, whether it is const or not, etc). It would then be much
> easier to work on that, rather than doing everything string-based.
>
> Simon
next prev parent reply other threads:[~2023-02-12 6:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-20 13:55 [PATCH] " Andrew Burgess
2023-01-20 11:48 ` [PATCHv2] " Andrew Burgess
2023-01-30 15:13 ` Andrew Burgess
2023-02-08 9:36 ` Bruno Larsen
2023-02-10 19:09 ` Andrew Burgess
2023-02-13 9:31 ` Bruno Larsen
2023-02-08 22:22 ` Simon Marchi
2023-02-10 19:10 ` Andrew Burgess
2023-02-10 19:03 ` [PATCHv3] " Andrew Burgess
2023-02-10 20:51 ` Simon Marchi
2023-02-12 6:22 ` Andrew Burgess [this message]
2023-02-13 14:14 ` Tom Tromey
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