Use -qualified flag when setting temporary breakpoint in start command
Commit Message
On 2019-04-09 12:30 p.m., Pedro Alves wrote:
> On 4/9/19 5:19 PM, Simon Marchi wrote:
>
>> I had initially changed start.exp to test both C and C++, then decided to just
>> keep C++ for simplicity. But your point about coverage is good, so I've done
>> as you suggested.
>>
>
> Thanks.
>
>> gdb/ChangeLog:
>>
>> * infcmd.c (run_command_1): Pass -qualified to tbreak when usind
>> the "start" command.
>
> Typo "usind".
Damn, I noticed this comment just after pushing. I fixed it in a follow up commit.
>>
>> gdb/testsuite/ChangeLog:
>>
>> * gdb.base/start-cpp.exp: New file.
>> * gdb.base/start-cpp.cc: New file.
>
> Note start-cpp.cc wasn't included in this patch -- don't forget
> to git add it.
Ah, I think it's because I've renamed it from start-cpp.cpp at the last minute,
when I noticed your comment about the extension.
Here's what the definitive version I pushed (with start-cpp.cc included).
Thanks for the review.
Simon
From e242fd1249ae85a97f08f95d5c61f4cbe3b906e0 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@efficios.com>
Date: Tue, 9 Apr 2019 12:32:26 -0400
Subject: [PATCH] Use -qualified flag when setting temporary breakpoint in
start command
When using the "start" command, GDB puts a temporary breakpoint on the
"main" symbol (we literally invoke the tbreak command). However, since
it does wild matching by default, it also puts a breakpoint on any C++
method or "main" function in a namespace. For example, when debugging
GDB, it creates a total of 24 locations:
(gdb) start
Temporary breakpoint 1 at 0x198c1e9: main. (24 locations)
as there are a bunch of methods called main in the selftests, such as
selftests::string_view::capacity_1::main()
If such method was called in the constructor of a global object, or a
function marked with the attribute "constructor", then we would stop at
the wrong place. Also, this causes a few extra symtabs (those that
contain the "wrong" mains) to be expanded for nothing.
The dummiest, most straightforward solution is to add -qualified when
invoking tbreak. With this patch, "start" creates a single-location
breakpoint, as expected.
I copied the start.exp test to start-cpp.exp and made it use a C++ test
file, which contains two main functions. The new test verifies that the
output of "start" is the output we get when we set a single-location
breakpoint.
gdb/ChangeLog:
* infcmd.c (run_command_1): Pass -qualified to tbreak when usind
the "start" command.
gdb/testsuite/ChangeLog:
* gdb.base/start-cpp.exp: New file.
* gdb.base/start-cpp.cc: New file.
---
gdb/ChangeLog | 5 ++++
gdb/infcmd.c | 5 +++-
gdb/testsuite/ChangeLog | 5 ++++
gdb/testsuite/gdb.base/start-cpp.cc | 33 +++++++++++++++++++++++++
gdb/testsuite/gdb.base/start-cpp.exp | 37 ++++++++++++++++++++++++++++
5 files changed, 84 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.base/start-cpp.cc
create mode 100644 gdb/testsuite/gdb.base/start-cpp.exp
@@ -1,3 +1,8 @@
+2019-04-09 Simon Marchi <simon.marchi@efficios.com>
+
+ * infcmd.c (run_command_1): Pass -qualified to tbreak when usind
+ the "start" command.
+
2019-04-08 Kevin Buettner <kevinb@redhat.com>
* python/py-inferior.c (infpy_thread_from_thread_handle):
@@ -604,7 +604,10 @@ run_command_1 (const char *args, int from_tty, enum run_how run_how)
/* Insert temporary breakpoint in main function if requested. */
if (run_how == RUN_STOP_AT_MAIN)
- tbreak_command (main_name (), 0);
+ {
+ std::string arg = string_printf ("-qualified %s", main_name ());
+ tbreak_command (arg.c_str (), 0);
+ }
exec_file = get_exec_file (0);
@@ -1,3 +1,8 @@
+2019-04-09 Simon Marchi <simon.marchi@efficios.com>
+
+ * gdb.base/start-cpp.exp: New file.
+ * gdb.base/start-cpp.cc: New file.
+
2019-04-08 Kevin Buettner <kevinb@redhat.com>
* gdb.python/py-thrhandle.exp: Adjust tests to call
new file mode 100644
@@ -0,0 +1,33 @@
+/* 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/>. */
+
+namespace foo
+{
+
+int
+main ()
+{
+ return 1;
+}
+
+} /* namespace foo */
+
+int
+main ()
+{
+ return foo::main ();
+}
new file mode 100644
@@ -0,0 +1,37 @@
+# Copyright 2005-2019 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/>.
+
+standard_testfile .cc
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
+ return -1
+}
+
+# This is a testcase specifically for the `start' GDB command. For regular
+# stop-in-main goal in the testcases consider using `runto_main' instead.
+
+# In this C++ version of the test (as opposed to start.exp), we specifically
+# test that the temporary breakpoint created by the start command has a single
+# location, even if we have a function named "main" in a non-root namespace.
+
+# For C++ programs, "start" should stop in main().
+if { [gdb_start_cmd] < 0 } {
+ untested start
+ return -1
+}
+
+gdb_test "" \
+ "Temporary breakpoint $decimal at $hex: file.*main \\(\\) at .*start-cpp.cc:.*" \
+ "start"